Kite <:' ' ri- WiJ • ty1. i.; i ■ • if ft fcifSij. IK t.i.i!ur.t:uvvivi'i)iivtH)Ut)Ul!SM(iV fill rj>l' tin 1-10-16-10N NATIONAL LIBRARY OF MEDICINE Bethesda, Maryland Gift of The New York Academy of Medicine (o. The sy- ne Wti AN INTRODUCTION TO THE STUDY OF ORGANIC CHEMISTRY. BY ADOLPH PINNER, Ph.D., PROFESSOR OF CHEMISTBHT IN THE UNIVERSITY OF BERLIN. / TRANSLATED AND REVISED FROM THE FIFTH GERMAN EDITION BY PETER T. AUSTEN, Ph.D., F.C.S., PROFESSOR OF ANALYTICAL AND APPLIED CHEMISTRY IN RUTGERS COLLEGE, AND THE NEW JERSEY STATB. SCIENTIFIC SCHOOL. _" THE I SECOND REVISE© EDITION F MEDICINE P1 r JG18 )ND THOUSAND. / Q % % Ti. O . l& LIBRARY NEW YORK: JOHN WILEY & SONS. 1894. Copyright, 1882, Bt JOHN WILEY & SONS &$ PRESS OF J. J. LITTLE 1 CO., NOS. 10 TO 20 ASTOR PLACE, NEW YORK. PEEFACE TO THE AMERICAN EDITION. As a teacher of organic chemistry, I have felt the want of a small book on the subject. There is no lack of dictionaries and encyclopaedic works on organic chemistry, but they are too large for use in a college course. The few shorter English text-books are not, so far as my experience goes, well suited for teaching. The following work, which has met with remarkable suc- cess in Germany, and which the author, Prof. Pinner, has kindly given me permission to translate, is founded on the system of teaching developed by the distinguished chemist Prof. A. W. Hofmann, of Berlin, and in some cases follows his lectures quite closely. The intention has been to make this book not a dictionary of compounds, or a work of reference for an investigator, but a text-book which can be placed in the hands of college stu- dents. It is believed that a student who has carefully studied aud faithfully recited this book will be able to take up under- standing^ the larger works. The retrospects at the end of each group afford the lect- urer an opportunity of introducing a detailed recapitulation of the facts considered, as well as a survey of the typical reactions and theoretical relations of the various classes of substances. Coming in this place, such information is under- stood and appreciated by the student who has become ac- quainted with the compounds, and understanding the deriva- tion of the individual members from each other, is prepared iv PREFACE TO THE AMERICAN" EDITION. to take up generalizations. But to begin with broad generali- zations and the consideration of involved relations among groups of compounds with which the student is not acquainted, is hardly more rational than to undertake to teach the gram- mar of a language by lectures in that language to students who have not the slightest knowledge of its vocabulary or its inflections. The unfortunate manner in which the subject is so frequently taught, is probably the reason why organic chemistry is so often looked upon by students as a mere exer- cise for the memory, and a dry, unprofitable study. In no other science has there been such remarkable develop- ment as in Organic Chemistry—the chemistry of the carbon compounds. Not so many years ago, Organic Chemistry was studied by but a few, and had but little practical importance. In fact, it was but little more than a description of a number of disconnected compounds, most of which occurred in plants and animals. But within the last few decades, the increase of facts and compounds has been almost in a geometric ratio. It is no more a study of plant extracts or animal substances alone, but a science with fixed laws, and abounding in deductions and inductions, and including in its pursuit a remarkable disci- pline for the student's powers of reasoning as well as of com- parison and judgment. The applications of Organic Chem- istry form the foundation of some of the greatest manufac- tures existing, and its progress involves the prosperity of nations. Some of the greatest problems known to man are being slowly worked out by this science. Instead of having but a few followers, it is not unsafe to say that more are devoting time to the study of this science than to any other. It seems to be the foundation of many of the other branches of study. The explanation of the vital phenomena of animal and vegetable life—in fact, the whole subject of biology—the study of ferments and fermentation, the action of medicines, the PREFACE TO THE AMERICAN EDITION. V nature of the innumerable organic drugs, and the myriads of compounds whose effects have not yet been studied, make the study of this science a necessity to the druggist, physician, biologist and scientific man. In many branches of manufacture the development of Or- ganic Chemistry has been startling, and the field seems to be practically unlimited. The production of the brilliant aniline colors, alizarine and indigo, the fragrant oil of bitter almonds, and many valuable drugs from the waste tar of the gas works, seems to the uninitiated little short of the miraculous. There is something wonderfully fascinating in the endless variations and permutations of the carbon compounds, the way in which, with a few atoms, the most complicated struct- ures are built up or torn to pieces at the bidding of the chemist. There is hardly any other science, with perhaps the exception of electricity, that affords such a field for experi- mental investigation, invention and practical applications, and this, too, with the use of but little apparatus and at but a slight expense. In this book the endeavor has been to explain the subject systematically, so that, with but a slight knowledge of chemical science, the student is able to advance easily to the most com- plicated compounds, and can at any place trace out the rela- tionships of the particular compound to the simple ones from which it is derived. It is believed that this text-book will be found to be indispensable, not only to the professional chemist and student, but also to the physician, druggist and chemical manufacturer. In translating Prof. Pinner's book, I have preserved so far as possible the easy lecture-style which is characteristic of it, and have not hesitated to employ numerous expressions which have come into use in working laboratories, and which recom- mend themselves for brevity and clearness. So far as the limits of the book allow, I have introduced the more important recent discoveries in organic chemistry, Vi PREFACE TO THE AMERICAN EDITION. and have made free use of the literature and text-books at my disposal. In particular, I have to acknowledge my in- debtedness to " Watt's Dictionary of Chemistry," the "Hand- worterbuch der Chemie," the English edition of Wislicenus- Strecker, and the large work of Eoscoe and Schorlemmer. P. T. A. CONTENTS. PAGE Introduction.................. 1 Definition of Organic Chem- istry..................... 1 Elementary Analysis....... 2 Determination of the Atomic Relation...... .......... 3 Determination of the Molecu- lar Formula.............. 5 Substitution................ 6 Isomerism.................. 6 Hydrocarbons............. 12 Homologous Series.......... 13 Saturated and Unsaturated Compounds............... 13 Methane Compounds.......... 15 Methane................... 15 Methyl Chloride............ 16 Methyl Bromide............ 16 Methyl Iodide............ 17 Methylene Chloride......... 17 Methylene Bromide......... 17 Methylene Iodide___....... 17 Chloroform................ 18 Bromoform................ 19 Iodoform................... 19 Carbon Tetrachloride....... 20 General Reactions of the Alkyl- ogens.................... 20 Hvdroxyl Substitutions....... 22 'Methyl Alcohol............ 23 General Properties of the Al- cohols Carbinols)......... 24 Methyl Ether............... f~8 Methylaldehyde............ 29 Methylal ................. 29 Formic Acid............... 30 General Remarks on Organic Acids................... 31 Orthoformic Acid.......... 31 Orthocarbonic Methyl Ester. 34 PAGE Carbonic Acid.............. 35 Chlorcarbonous Oxide...... 35 Sulphosubstitution-Products of Methane................. 36 Methylsulphydrate.......... 36 Methyl Mercaptan.......... 36 Methyl Sulphaldehyde...... 36 Carbon Disulphide.......... 36 Carbon Oxysulphide........ 37 Sulphocarbonic Acids....... 37 Trisulphocarbonates......... 38 Disulphocarbonates........ 38 Xanthogenates............... 38 Monosulphocarbonates...... 38 Sulphocarbonyl Chloride___ 38 Methylsulphonic Acid....... 39 Methylenesulphonic Acid ... 39 Methylsulphone............ 39 Nitrogen Derivatives of Me- thane .................... 40 Amines..................... 41 Amides.................... 41 Amic Acids................ 42 Imides.................... 42 Nitriles.................... 43 Nitro-Compounds........... 44 Ammoniums............... 45 Methylamine............... 45 Dimethylamine............ 46 Trimethylamine............. 46 Behavior of Amine Nitrites.. 46 Nitroso-Compounds......... 46 Hydrazine-Com pounds...... 46 Tetramethylammonium Iod- ide..................... 47 Tetramethylammonium Hy- droxide................. 47 Formation of Amines....... 47 Amides and Amic Acids......48 Formamide............... 48 CONTENTS. TAGE Carbamic Acid............. 48 Urethanes................. 48 Methylurethane............ 48 Carbamide, Urea.......... 49 Atomic Migration.......... 49 Salts of Urea.............. 49 Decompositions of Urea..... 50 Ethylureas............... 51 Allophanic Acid........... 51 Biuret ................... 51 Sulphocarbamic Acid....... 51 Sulphocarbamide........... 52 Guanidine.................. 52 Cyanhydric Acid........... 53 Sodium Cyanide............ 54 Potassium Cyanide.......... 55 Silver Cyanide............. 55 Ammonium Cyanide........ 55 Mercury Cyanide........... 56 Ferrocyan, Prussian........ 56 Potassium Ferrocyanide..... 56 Potassium Ferrous Ferrocy- anide.................... 57 Potassium Nitroprusside.... 57 Hydroferrocyanic Acid...... 57 Ferric Ferrocyanide........ 58 Prussian Blue.............. 58 Cupric Ferrocyanide........ 58 Potassium Ferricyanide..... 68 Turnbull's Blue............ 58 Hydroferricyanic Acid...... 58 Potassium Manganocyanide . 58 Potassium Manganicyanide . 58 Potassium Chromicyanide... 59 Potassium Cobalticyanide... 59 Hydrocobalticyanic Acid___ 59 Chlorcyan................. 59 Trichlorcyan............... 59 Bromcyan................. 59 Iodocyan.................. 59 Cyanmethyl................ 60 Methyl Cyanurate.......... 60 Methyl Isocyanide ......... 60 Compounds of Cyanic Acid.. 62 Cyanic Acid................ 62 Cyanuric Acid............. 62 Cyamelid.................. 62 Potassium Cyanate........ 63 Potassium Isocyanate....... 63 Ammonium Cyanate........ 63 Methyl Cyanic Ether........ 63 PAGE Methyl Isocyanic Ether..... 63 Methyl Cyanuric Ether..... 63 Sulphocyanic Acid......... 64 Potassium Sulphocyanate... 64 Ammonium Sulphocyanate.. 64 Mustard-Oils............... 64 Methyl Sulphocyanic Ether.. 64 Methyl Mustard-Oil........ 64 Cyanogen.................. 65 Azulmic Acid ............. 65 Paracyan.................. 66 Cyanamide................ 66 Dicyandiamide............. 66 Dicyandiamidine, Param.... 66 Cyanuramide Melamine..... 66 Ammeline................. 66 Nitromethane.............. 66 Sodium Nitromethane....... 66 Bromnitrom ethane......... 66 Methylnitrolic Acid........ 66 Chlorpicrine, Nitrochloro- form.................... 66 Nitroform.................. 66 Tetranitromethane......... 67 Fulminic Acid............. 67 Mercuric Fulminate........ 67 Silver Fulminate........... 67 Fulminuric Acid.......... 67 Dinitrocyanmethane........ 67 Trinitrocyanmethane....... 67 Phosphorus Derivatives of Me- thane.................... 67 Phosphines................ 67 Phosphinic Acids........... 68 Methylphosphine........... 68 Methyl phosphonium Iodide. 68 Methyl phosphinic Acid..... 68 Dimethylphosphine......... 68 Dimethylphosphinic Acid. .. 68 Trimetnylphosphine........ 68 Tetramethy 1 phosphonium Iodide................... 69 Tetramethyl phosphon ium Hydroxide.............. 69 Methylhydrazin............. 69 Phosphorus Dimethyl....... 69 Silico-acetic Acid............ 70 Arsenic Derivatives of Me- thane ................... 70 Monomethyl-arsenic Dichlo- ride..................... 70 CONTENTS. PAGE Monomethyl-arsenic Tetra- chloride ................. 70 Dimethyl-arsenic Dichloride. 70 Dimethy I -arsenic Trichloride. 70 Trimethylarsine............ 70 Tetramethylarsonium Iodide. 70 Tetramethylarsonium Hydr- oxide.................... 71 Cacodyl, Arsenic Dimethyl.. 71 Cacodylic Oxide, Alcarsine.. 71 Cacodylic Acid, Dimethyl- arsenic Acid.............* 71 Methylarsinic Acid......... 71 Antimony Derivatives of Me- thane ................... 71 Trimethylstibine............ 71 Tetramethyl stibonium Iodide 71 Tetrametliylstibonium Hy- droxide .................. 71 Trimethylstibine Iodide..... 71 Trimethyl Bismuthine........ 71 Trimethyl Borine............. 71 Compounds of Methyl with Met- als .................... 72 Methyl Zinc Iodide......... 72 Zinc Methyl................ 72 Mercury Methyl Iodide...... 72 Mercury Methyl............ 72 Magnesium Methyl......... 72 Tetramethyl Silicium....... 72 Tin Tetramethyl........... 72 Lead Tetramethyl.......... 72 Methylsulphuric Acid......... 73 Methylsulphuric Ester........ 73 Methyl Nitric Ester........... 73 Methyl Boric Ester........... 73 Methyl Silicic Ester........... 74 Ethane Compounds........... 75 Ethane, Dimethyl........... 75 Ethylene................... 75 Ethylene Oxide............. 76 Acetylene.................. 76 Compounds of Acetylene.... 76 Halogen Substitutions of Ethane 77 Ethyl Chloride............. 77 Ethyl Bromide............. 77 Ethyl Iodide............. 77 Ethylene Chloride, Dutch Li- quid..................... 77 Ethylidene Chloride......... 77 Monochlorethvlidene........ 77 PAGB Monochlorethylene Chloride. 78 Monochiorethylidene Chloride 78 Dichlorethylene Chloride___ 78 Dichlorethylidene Chloride.. 78 Pentachlorethane........... 78 Perchlorethane............. 78 Ethylene Bromide.......... 78 Ethylidene Bromide........ 79 Ethylene Iodide........... 79 Monochlorethylene......... 79 Dichlorethylene............ 79 Trichlorethylene............ 79 Tetrachlorethylene.......... 79 Hydroxyl Substitutions of Eth- ane...................... 80 Ethyl Alcohol, Alcohol...... 80 Isethionic Acid............. 82 Taurine.................... 82 Amidoethylidene-sulphonic Acid..................... 82 Nitric Ethyl Ester.......... 83 Nitrous Ethyl Ester........ 83 Ether...................... 83 Monochlorether............. 84 Diehlorether............... 84 Tetrachlorether............. 84 Perchlorether.............. 84 Methylethylether........... 84 Aldehyde.................. 84 Characteristics of the Alde- hydes.................... 85 Aldehyde-Ammonia........ 86 Thialdine.................. 86 Aldehyde-Resin............ 86 Paraldehyde............... 86 Metaldehyde............... 86 Crotonic Aldehyde.......... 86 Aldol...................... 86 Acetal..................... 87 Monochloraldehyde......... 87 Dichloraldehvde............ 87 Trichloraldetiyde, Chloral... 87 Chloral Hydrate............ 87 Chloral Alcoholate.......... 87 Chloral Cyanhydrate........ 88 Bromal.................... 88 Bromal Hydrate............ 88 Acetic Acid, Vinegar........ 88 Ortho-acetic Acid........... 89 Volumetric Analysis........ 89 Potassium Acetate.......... 89 CONTENTS. Sodium Acetate............ 89 Zinc Acetate............... 89 Plumbic Acetate ........... 89 Basic Lead Acetate......... 9U Cupric Acetate............. 90 Silver Acetate.............. 90 Ethylacetic Ester........... 90 Characteristics of the Esters of the Organic Acids...... 90 Aeeto-acetic Ester.......... 91 Sodium Acetoacetic Ester... 91 Ethyl Acetoacetic Ester..... 92 Di-ethylacetoacetic Ester.... 92 Acetyl Chloride............ 93 Acetyl Cyanide............. 93 Acetamide................. 93 Di-acetamide............... 94 Tri-acetamide.............. 94 Acetic Anhydride.......... 94 Acetyl Superoxide.......... 94 Monochioracetic Acid....... 95 Dichloracetic Acid.......... 95 Ethyl Dichloracetic Ester... 95 Trichloracetic Acid......... 95 Acetosulphonic Acid........ 95 Glycols.................... 95 Ethylene Glycol............ 96 Glycolchlorhydrin.......... 96 Di-ethylene Glycol.......... 96 Tri-ethylene Glycol......... 96 Glycollic Acid.............. 97 Ethoxyglycollic Acid........ 97 Glycollic Chloride.......... 97 Glycolamide............... 98 Glycocoll................... 98 Copper Compound of Glyco- coll ..................... 98 Poly-glycollic Acid......... 98 Di-glycollic Acid........... 98 Glycollide................. 98 Glyoxal ................. 98 Glyoxalic Acid............. 98 Oxalic Acid................ 98 Potassium Hydrogen Oxalate 99 Ammonium Hydrogen Oxa- late..................... 99 Ammonium Oxalate ....___ 99 Calcium Oxalate .......... 99 Methyloxalic Acid.......... 100 Oxalic Methyl Ester........ 100 Ethyloxalic Acid........... 100 PAGE Oxalic Ethyl Ester......... 100 Oxamic Acid............. 100 Oxamide.................. 100 Di-ethyloxamide............ 101 Chloroxalmethyline......... 1°1 Chloroxalethyline.......... 101 Sulphosubstitutions of Ethane. 101 Ethylmercaptan............ 101 Ethyl Sulphide............. 102 Di-ethylsulphone........... 102 Tri-ethylsulphine Iodide.... 103 Ethyl Disulphide........... 103 Ethylsulphaldehyde........ i03 Thiacetic Acid............. 103 Thiacetic Anhydride........ 103 Ethylsulphonic Acid........ 103 Nitrogen Substitutes of Ethane 104 Ethylamine................ 104 Di-ethylamine.............104 Tri-ethylamine............. 104 Tetra-ethylammonium Iodide 104 Tetra-ethylammonium Hydr- oxide................... 104 Ethylene-diamine.......... 104 Di-ethylene-diamine........ 104 Tri-ethylene-diamine.......104 Trimethyloxethylammonium Chloride................. 104 Choline.................... 104 Trimethyloxethylammonium Hydroxide............... 104 Trimethyliodoethylammoni- um Iodide................ 105 Neurine................... 105 Betai'ne................... 105 Nitroethane................ 105 Ethylphosphine.............. 105 Di-ethylphosphine............ 105 Tri-ethylphosphine............ 105 Ethylphosphinic Acid........ 105 Di-ethylphosphinic Acid...... 105 Tri-ethylphosphinic Acid...... 105 Tri ethylarsine............... 105 Tri ethylstibine.............. 105 Zinc Ethyl................... 105 Mercury Ethyl............... 105 Ethyl Cyanide................ 105 Ethyl Isocyanide............. 106 Ethyl Cyanic Ether........... 106 Ethyl Cyanuric Ether......... 106 Ethyl Isocyanie Ether......... 106 CONTENTS. Ethyl Mustard-Oil............ 106 Ethyl Sulphocyanide.......... 106 Propane Compounds.......... 107 Propyl Compounds.......... 107 Isopropyl Compounds....... 107 Propane................... 107 Propylene................. 107 Allylene................... 108 Allylene Dibromide......... 108 Allylene Tetrabromide...... 108 Propyl Chloride............ 108 Isopropyl Chloride.......... 108 Propyl Bromide............ 108 Isopropyl Bromide.......... 108 Propyl Iodide.............. 108 Isopropyl Iodide............ 108 Propylene Chloride......... 108 Dichlorpropylene........... 108 Propyl Alcohol............. 108 Isopropyl Alcohol........... 109 Propionaldehyde........... 110 Dimethylketone............. 110 Acetone .................. 110 Monochloracetone.......... 11 Dichloracetone.............. 11 Trichloracetone............ 11 Tetrachloracetone.......... 11 Pentachloracetone..........11 Perchloracetone............ 11 Ketones................... 11 Mixed Ketones............. 112 Methylethylketone.......... 112 Di-ethylketone.............. 112 Pinacones.................. 113 Tertiary Methylbutylketone . 113 Pinacolines................. 113 Propionic Acid............. 113 Propyl Glycol.............. 114 Isopropyl Glycol........... 114 Propylglycollic Acid........ 114 Ethylene-glycol............ 114 Malonic Acid.............114 Acrylic Acid.............. 114 Lactic Acid................ 114 Lactide.................... 115 Magnesium Lactate......... 116 Zinc Lactate............... 116 Ferrous Lactate............ 116 Ethyl Lactic Acid........... 116 Ethyl Lactic Ester......... 116 Lactamic Acid............. 116 PAGE Lactamide................ 116 Sarcolactic Acid............ 116 Paralactic Acid............. 116 Malonic Acid............... 117 Malonic Ethyl Ester........ 117 Pyroracemic Acid........... 117 Glycerol................... 118 Monacetin................. 118 Di-acetin................... 118 Tri-acetin.................. 118 Monethylglycerol........... 118 Di-ethylglycerol............. 118 Tri-ethylglycerol............ 118 Nitroglycerine.............. 119 Dynamite.................. 119 Glyceryl Sulphuric Ester___ 119 Glyceryl Phosphoric Ester... 119 Lecithin................... 119 Monochlorhydrin........... 119 Dichlorhydrin.............. 119 Epichlorhydrin............. 120 Trichlorhydrin............. 120 Bromhydrins............... 120 Chlorbromhydrins.......... 120 Polyglycerols............... 120 Glyceric Acid.............. 120 Tartronic Acid............. 121 Glycolide.................. 121 Mesoxalic Acid............. 121 Allyl Iodide................ 122 Allyl Tribromide........... l'~2 Allyl Tricyanide............ 122 Allyltricarballylic Acid...... 122 Allyl Alcohol............... 122 Sodium Alloxide............ 122 Allyl Ether................ 122 Acrole'ine.................. 123 Disacryl................... 123 Acroleine Hydrochloride. .. 123 Acrylic Acid............... 123 Allyl Cyanide.............. 124 Allyl Isocyanide............ 124 Mustard-Oil................ 124 Thiosinamine............... 124 Sinapoline................. 124 Allyl Sulphocyanate........ 124 Allyl Sulphide............. 125 Propylamine............... 125 Isopropylamine............. 125 Alanine.................... 125 Butane Compounds........... 126 x.i CONTENTS. PAGE PAGE 126 Potassium Sodium Tartrate 137 1?6 137 126 137 136 137 127 138 Tertiary Butyl Chloride___ 1?,7 138 127 138 Secondary Butyl Iodide.... 187 138 127 Erythrol Nitric Ester...... 139 m 139 127 139 Secondary Butyl Alcohol... 127 139 198 139 189 139 129 14(1 130 140 131 140 130 Pentane Compounds......... 141 131 Normal Amyl Compounds... 141 131 141 132 141 132 141 139, Ordinary Amyl Alcohol___ 142 132 1451 13?, 14» 132 Secondary Butyl Carbinol... . 142 13?, Isopropylmethyl Carbinol... . 142 132 Propvlmethyl Carbinol. ... 142 Succinic Acid............. 133 14?, Suecinyl Chloride......... 133 Ethyldiinethyl Carbinol.... 143 Succinamide.............. 133 Normal Valeraldehyde..... 142 134 Ordinary Valeraldehyde.... 143 134 Normal Valerianic Acid.... 143 Dibromsuccinnic Acid..... 134 Ordinary Valerianic Acid... 143 134 Bismuth Valerianate....... 143 134 Zinc Valerianate.......... 143 Malic Acid................ 134 Trimethylacetic Acid...... 143 135 144 136 144 Isomalic Acid............. 136 Pyrotartaric Acid......... 144 '136 144 136 144 Ditartaric Acid........... 136 144 Tartrelic Acid............ 136 144 Pyroracemic Acid......... 136 145 Pyrotartaric Acid......... 136 Dimethylpropyl Carbinol... . 145 136 Normal Hexyl Alcohol..... 145 137 Secondary Hexyl Alcohol... . 145 Hydrogen Ammonium Tar Di-ethylmethyl Carbinol.... 145 137 145 137 , 145 CONTENTS. PAGE PAGE ... 152 ... 146 Hemp-Oil............... ... 152 Aconitic Acid.......... 146 ... 146 Poppy-Oil............... ... 152 Citraconic Acid........ Carbhydrates............. ....153 Itaconic Acid.......... ... 146 ... 154 Mesaconic Acid........ ... 146 ... 155 Paraconic Acid. ....... ... 146 Diastase................ .. 155 Calcium Citrate........ ... 147 ... 156 Magnesium Citrate..... ... 147 ... 147 Lactic Ferment......... ... 156 ... 147 Mucous Ferment........ .. 156 ... 147 Levulose................ ... 157 ... 147 .. 157 Dulcite................ ...148 Cane-Sugar............. ... 157 ...148 Caramel................. ... 158 ... 148 Inverted Sugar.......... .. 158 ... 148 .. 158 ... 148 .. 159 ... 148 .. 159 Normal Heptyl Alcohol... ... 148 Melizitose............... .. 159 .... 148 .. 159 ...148 .. 159 ...148 .. 160 ... 148 Inulin.................. .. 160 ... 148 Lichenin................ .. 160 Capric Acid............... ... 148 Paramylum............. .. 160 Saponification............. ... 149 Glycogen............... .. 160 ... 149 Dextrine................ .. 161 Myristic Acid............. ... 149 ... 161 ... 149 ... 161 ... 149 -. 162 ... 149 .. 162 ... 149 Mucilage............... .. 162 ... 150 Pectine Substances....... ... 163 ... 150 ... 163 ... 150 ... 163 ... 150 ... 163 ... 150 .. 163 ... 150 .. 164 ... 150 ... 164 ... 150 .. 165 ... 150 ... 167 ... 150 .. 167 Fats...................... ... 150 Dialuric Acid........... .. 167 ... 151 .. 168 Olive-Oil............... ... 152 .. 168 . 152 ... 152 .. 168 Palm-Oil............... .. 168 Almond-Oil............. ... 152 .. 168 ... 152 Dibrombarbituric Acid... .. 168 ... 152 .. 168 ENTS. xiv PAGE Dilituric Acid.............. 168 VioJuric Acid.............,. 168 Parabanic Acid............. 169 Oxaluric Acid.............. 169 Allanturic Acid............ 109 Hydanto'ine................ 169 Allantoine.................. 169 Hydantoie Acid............ 170 Xanthine..................... 170 Sarcine...................... 170 Carnine..................... 170 Theobromine.................170 Caffeine..................... 170 Theme...................... 170 Guanine..................... 171 Creatine...........,......... 171 Creatinine................... 172 Sarcosine..................... 172 Methyluramine...............172 Glycocyamine................ 172 Retrospect................... 174 Hydrocarbons.............. 174 Saturated Hydrocarbons.....177 Unsaturated Hydrocarbons.. 177 Halogen Derivatives......... 180 Hydroxyl Derivatives....... 182 Aldehydes................. 186 Ketones................... 187 Acids....................... 187 Aci-chlorides............... 189 Acid Anhydrides............ 189 Thio-acids.................. 189 Hydroxy-acids.............. 191 Esters..................... 191 Amine Bases............... 192 Cyanides................... 194 Isocyanides................ 194 Nitro-compounds........... 195 Sulphonic Acids ........... 195 Metallo-compounds.......... 195 Aromatic Compounds......... 196 Constitution................ 196 Isomerism of............... 197 Benzene..................... 202 Monochlorbenzene..........204 Diphenyl.................. 204 Dichlorbenzene............. 204 PAGE 2A5 205 905 205 205 205 Tribrom benzene........... 205 905 206 906 906 206 906 206 206 207 207 Zinc Benzene-sulphinate ... . 207 Benzene-disulphonic Acid.. . 207 Benzene-trisulphonic Acid. . 207 207 . 207 ?,09 209 , 209 2,09 909 909 9,09 2,09 210 Potassium Picrate......... 210 ?,1 n Monochlornitrophenol...... 210 . 210 Pheneto'il................. . 210 Phenyl Ether............. , 210 Phenol-sulphonic Acid.... ?11 Phenol-disulphonic Acid... . 211 Phenol-trisulphonic Acid... . 211 Phenyl Mercaptan......... . 211 Phenyl Sulphide........... 211 211 Catechol................. . 212 Resorcinol................ . 212 Trinitroresorcinol......... ?,1?, Quinol................... . 212 212 . 212 . 213 . ?13 CONTENTS. xv Pyrogallic Acid............. 214 Phlorglucin............... 214 Aniline..................... 215 Substitutions.............. 216 Methylaniline.............. 216 Dimethylaniline............ 216 Ethylaniline............... 216 Ethylenediphenyldiamine--- 217 Di-ethylenediphenyldiamine. 217 Ethylenephenylamine....... 217 Ethylidenediphenyldiamine . 217 Di-ethylidenediphenyldi- amine................... 218 Methenyldiphenyldiamine... 218 Ethenyldiphenyldiamine.... 218 Formanilide............... 218 Acetanilide................218 Sulphoearbanilamide....... 219 Carbanilic Acid............. 220 Carbanilide................ 220 Carbanilamide............. 220 Carbanile..................221 Sulphocarbanilide..........221 Diphenylguanidine......... 221 Triphenylguanidine.........221 Sulphocarbanile............ 222 Diphenylamine............. 222 Triphenylamine............ 222 Phenylenediamine.......... 222 Ethylenephenyleneamidine.. 223 Phenylenealdehydine....... 223 Triamidobenzene........... 223 Azoxybenzene.............. 224 Azobenzene................ 224 Hydrazobenzene............ 224 Benzidine.................224 Diazo-amido-benzenc........ 234 Diazobenzene Nitrate.......224 Hydrazine Compounds......226 Amido-azobenzene..........226 Diazo-di-amido-azobenzene... 226 Tri-amido-azobenzene....... 226 Chrysoi'dine................226 Diazo-colors............... 226 Benzonitrile................ 226 Isocyanbenzene............. 228 Phosphenyl Chloride..........228 Phenyl-hypophosphorous Acid.. 228 Phosphenyl Tetrachloride.....228 Phenyl Oxychloride........... 228 Phenylphosphinic Acid....... 228 Phenylphosphine.............228 Mercury Phenyl.............. 228 Toluene...................... 229 Monochlortoluene..........233 Benzyl Chloride............233 Dichlortoluene.............. 233 Monochlorbenzyl Chloride... 233 Benzal Chloride............. 233 Trichlortoluene.............234 Dichlorbenzyl Chloride.....234 Nitrotoluene............... 234 Cresol..................... 235 Benzyl Alcohol.............236 Benzyl Acetic Ester........237 Benzyl Benzoic Ester....... 237 Benzyl Cinnamic Ester...... 237 Benzaldehyde.............. 237 Benzoin...................238 Benzil.................... 238 Benzilic Acid.............. 238 Hydrobenzoin.............. 238 Desoxybenzoin............. 238 Isohydrobenzom............ 238 Amarine...................238 Lophine................... 238 Phenylglycollic Acid....... 238 Phenylamido-acetic Acid--- 239 Stilbene................... 239 Benzoic Acid............... 239 Benzophenone............. 241 Dinitrobenzophenone....... 241 Benzhydrol................ 241 Acetophenone.............. 241 Methylphenyl Carbinol...... 241 Benzoyl Chloride........... 241 Benzoyl Bromide........... 242 Benzoyl Iodide............. 242 Benzoyl Cyanide........... 242 Benzotrichloride........... 242 Benzoic Anhydride......... 242 Benzoyl-acetic Anhydride ... 242 Benzamide................. 242 Methyl Benzoic Ester....... 242 Ethylbenzoic Ester......... 242 Phenyl Benzoic Ester....... 243 Monochlorbenzoic Acid..... 243 Chlorsalylic Acid.......... 243 Chlorbenzoic Acid.......... 243 Chlordracylic Acid......... 243 Nitrobenzoic Acid ......... 244 Azoxybenzoic Acid.........244 XVI CONTENTS, PAGE Azobenzoic Acid........... 244 Hydrazobenzoic Acid.......244 Dinitrobenzoic Acid........ 244 Trinitrobenzoic Acid........ 244 Amidobenzoic Acid......... 244 Anthranilic Acid........... 244 Amidodracylic Acid........ 245 Sulphobenzoic Acid......... 246 Sulphobenzoyl Chloride.....246 Sulphobenzoyl Dichloride___ 246 Sulphobenzamic Acid....... 246 Sulphobenzamide........... 246 Benzylamine................ 247 Dibenzylamine............. 247 Tribenzylamine............ 247 Benzylphosphine............ 247 Dibenzylphosphine.........247 Tribenzylphosphine........247 Benzyl Cyanide............ 247 Alphatoluic Acid........... 247 Benzyl Sulphydrate......... 247 Benzyl Sulphide............ 247 Benzyl Disulphide.......... 247 Hippuric Acid............. 247 Benzoylglycollic Acid.......248 Ethyl Hippuric Ester....... 248 Hippuramide............... 248 Orcinol.................... 248 Archil.................... 248 Litmus.................... 248 Beta-orcinol...............250 Guaicol..................... 250 Creasote................... 250 Trichlortoluenequinone...... 250 Trichlortoluquinol.......... 250 Saligenin, Salicyl Alcohol.. . 251 Salicylic Aldehyde.......... 251 Salicylic Acid.............. 252 Nitrosalicylic Acid.........253 Amidosalicylic Acid........ 253 Salicylamide............... 253 Hydroxybenzoic Acid....... 253 Parahydroxybenzaldehyde .. 254 Parahydroxybenzoic Acid... 254 Anisyl Alcohol.........___254 Anisic Aldehyde........... 254 Anisic Acid................ 254 Hydroxysalicylie Acid...... 255 Parahydroxysalicylic Acid .. 355 Protocatechuic Acid....... 255 Veratric Acid.............. 255 Vanillin................... Coniferin................... Gentisin................... Gallic Acid................ Tannin..................... Toluidine...........:...... Aniline Colors............. Fuehsine................... Rosaniline................. Rosaniline Trihydrochloride Leucaniline............... Diphenyltolylmethane.. .... Methyl-Violet............. Ethyl-Violet............... Aniline-Blue.............. Iodine-Green.............. Chrysaniline............. Pentamethylrosanilino...... Penta-ethylrosaniline....... Triphenylrosaniline ....... Aniline-Black.............. Rosolic Acid............... Leucorosolic Acid........... Xylene....................... Derivatives............... Tolyl Alcohol.............. Toluic Acid................ Phenylglycollic Acid....... Phenylglyoxylic Acid....... Phthalic Acid.............. Phthalic Anhydride........ Isophthalic Acid............ Terephthalic Acid.......... Xylidine................... Phenolphthalei'n...... Phenol Phthalin............ Phenolphthalidin........... Fluorescin................. Eosin...................... Monoresorcinolphthalei'n___ Dibromresorcinol Phthale'in. Gallein..................... Gallem Anhydride.... Gallin....................[ Cumene...................... Trimethylbenzene........... Methylethylbenzene........ Propylbenzene.............. Pseudocumene............. Mesitylene................. Isopropylbenzene, Cumene .. 255 255 255 256 256 257 257 258 258 258 258 258 259 259 259 259 260 260 260 260 260 260 261 261 261 261 262 262 263 263 263 264 264 264 264 264 265 265 265 2G5 265 265 266 266 266 266 266 £66 266 266 267 CONTENTS. PAGE Xylic Acid................. 267 Paraxylic Acid............. 267 Xylidie Acid............... 267 Mesitylenic Acid............ 267 Uvitic Acid................ 268 Trimesic Acid.............. 268 Trimellitic Acid............ 268 Hemimellitic Acid.......... 268 Ethylbenzoic Acid..........268 Hydro-atropic Acid......... 268 Benzopropionic Acid........ 268 Cinnyl Alcohol............. 269 Cinnyl Ether............... 269 Cinnamic Chloride..........269 Cinnamine................. 269 Cinnamic Aldehyde......... 269 Cinnamic Acid............. 270 Phenylcrotonic Acid........ 270 Phenylangelic Acid......... 270 Cinnamyl Chloride......... 271 Cinnamyl Amide........... 271 Hydrocinnamic Acid........271 Cinnamic Anhydride........ 271 Styrolene.................. 271 Metastyrolene.............. 271 Distyrolene................ 271 Phenylacetylene............ 271 Cinnamein................ 272 Styarcin................... 272 Cumaric Acid..............272 Cumarin.................. 272 Melilotic Acid.............. 273 Hydrocumarin..............273 Caffetannic Acid............ 273 Caffeic Acid.....'........... 273 Hydrocaffeic Acid.......... 273 Umbelliferon...............273 Hydroiimbellic Acid........ 274 Daphnetin................. 274 Cymene....".................. 274 Durene.................... 274 Dimethy Jethylbenzene.......274 Di-ethylebenzene...........274 Butylbenzene.............. 275 Isobutylbenzene............ 275 Thymol....................275 Cymyl Alcohol............. 275 Cumic Aldehyde............ 275 Cumic Acid................ 275 Pyromellitic Acid...........275 PAGE Phrenitic Acid............. 275 Mellophanic Acid........... 275 Mellitic Acid...............275 Reduction of Benzene Deriva- tives.....................276 Trichlorphenose............277 Phenose .................. 277 Hydrophthalic Acid........278 Tetrahydrophthaiic Acid... 278 Hexahydrophthalic Acid___278 Hydrobenzoic Acid......... 278 Hydroterephthalic Acid.....278 Bromomalophthalic Acid.... 278 Tartrophthalic Acid........278 Hydropyromellitic Acid..... 276 Hydromellitic Acid.......279 Indigo-group................. 279 Indigo-Blue................ 280 Sulphopurpuric Acid........ 280 Indigo tindisulphonic Acid... 280 Indigo-White............... 281 Isatin......................281 Isatid...................... 281 Dioxindole................. 281 Oxindole..................282 Indole..................... 282 Indican....................282 Nitroso oxindole............ 282 Amido-oxindole............. 282 Isatinie Acid............... 283 Orthonitrophenylpropiolic Acid..................... 283 Isatogenic Ethyl Ester...... 283 Indoxylic Ethyl Ester........ 283 Ethoxyindoxylic Ethyl Ester 284 Indoxylic Acid.............284 Ethoxyindoxylic Acid....... 284 Ethoxynitroso-indoxylic Acid 284 Indoxyl...................285 Ethoxyindoxyl............. 285 Orthonitrophenylacetylene.. 285 Di-acetylenephenyl......... 285 Di-isatogen................ 285 Diphenol..................... 287 Paraleucaniline............... 288 Pararosaniline................ 288 Fluorcne..................... 288 Diphenylbenzene ............ 288 Carbazol..................... 288 Acridine..................... 288 xviii CONTENTS. Retrospect................... 289 Hydroxyl Derivatives....... 289 Carboxyl Derivatives........ 289 Hydrocarbons.............. 289 Naphthalene.................292 Isomeric Substitutions...... 293 Naphthalene Dichloride.....294 Naphthalene Tetrachloride.. 294 Monochlornaphthalene...... 295 Monochlornaphthalene Tetra- chloride .................. 295 Dichlornaphthalene.........295 Trichlornaphthalene........295 Tetrachlornaphthalene......295 Perch! ornaphthalene........295 Bromnaphthalene..........295 Dibroranaphthalene......... 295 Tribromnaphthalene........295 Tetrabromnaphthalene......295 Nitronaphthalene........... 295 Dinitronaphthalene......... 296 Trinitronaphthalene........ 296 Tetranitronaphthalene......296 Naphthalenesulphonic Acid.. 296 NaphthalenedisulphonicAcid 297 Naphthalenetetrasulphonic Acid....................297 Naphthol.................. 297 Dihydroxynaphthalene...... 297 Trihydroxynaphthalene.....298 Naphthoquinone........... 298 Dichlornaphthoquinone..... 298 Dichlornaphthoquinol....... 298 Chloroxynaphthalic Acid___ 298 Naphthazarin.............. 298 Pentachlornaphthalene...... 293 Cyannaphthalene........... 298 Dicyannaphthalene.........299 Naphthalenedi carboxyl ic Acid 299 Napththalidine............. 299 Di-amidonaphthalene....... 299 Triamidonaphthalene........ 299 Naphthene Alcohol......... 299 Methylnaphthalene......... 299 Dimethylnaphthalene....... 299 Phenanthrene................. 300 Chrysene.................... 300 Picene.......................301 Diphenic Acid................ 301 PA8B Anthracene.................. 301 Anthracene Dichloride.. ... 302 DibromanthraceneDibromide 302 Anthracene-carboxylic Acid. 302 Anthraquinone............. 302 Anthraquinone-disulphonic Acid.................... 302 Alizarin................... 302 Hydroalizarin.............. 303 Alizarin-Blue.............. 303 Purpurin.................. 303 Antnraflavic Acid.......... 304 Isanthraflavic Acid.........304 Franguline................ 304 Frangulic Acid............ 304 Quinazarin................. 304 Purpuroxanthin............ 304 Chrysazin.................. 304 Anthrapurpurin............ 304 Flavopurpurin............,. 304 Anthrachrysone............ 304 Rufiopin................... 304 Rufigallic Acid............. 304 Chrysophanic Acid......... 304 Chrysophan................ 304 Chrysene..................... 304 Chrysoquinone.............305 Chrysoquinol............... 305 Dichlorchrysoquinol........ 305 Perchlorchrysoquinone...... 305 Retene...................... 305 Fluoranthrene.............. 305 Pyrene...................... 305 Picene....................... 305 Camphor-Group.............. 305 Camphor.................. 306 Monobromcamphor......... 306 Campholic Acid............ 306 Camphoric Acid............ 306 Bo-neo-camphor........... 306 Cunric Phenol.............. 307 Peppermint-camphor.......308 Elecampane-camphor....... 308 Helenine................... 308 Camphor-Oil............... 308 Essential Oils................308 Turpentine-Oil............. 309 Terpin.................... 310 Terpene Dihydrochloride.... 310 Terpene Monohydrochloride. 310 Terebic Acid............... 310 CONTENTS. PAGE Terpene Dibromide.........310 Lemon-Oil................. 310 Valerian-Oil................ 310 Caraway-Oil...............310 Roman Caraway-Oil........310 Clove-Oil.................. 310 Eugenol................... 310 Coniferyl Alcohol.......... 310 Ferulic Acid...............311 Thyme-Oil.................311 Parsley-Oil................ 311 Wormwood-Oil.............311 Rose-Oil................... 311 Anise-Oil.................. 311 Fennel-Oil................. 311 Bitter Almond-Oil..........311 Cinnamon-Oil..............311 Mustard-Oil............... 311 Leek-Oil................... 311 Spoonwort-Oil............. 311 Resins....................... 311 Rosin...................... 312 Copaiba Balsam............ 312 Guaiacum Balsam..........312 Shellac.................... 312 Balsam of Peru............ 312 Storax.....................312 Balsam of Tolu............312 Benzoin Resin.............. 312 Aloes...................... 312 Jalap......................312 Mastic.....................312 Gum-Ammoniac............ 312 Gum-Galbanum.... .......312 Asafcetida.................. 312 Euphorbium............... 312 Gum-Elimi.................313 Frankincense.............. 313 Myrrh .................... 313 Caoutchouc................313 Gutta Percha............... 313 Asphalt................... 313 Pyridine Bases............... 313 Pyridine................... 314 Picoline................... 314 Collidine................... 314 Lutidine................... 314 Parvoline.................. 314 Quinoline.................. 315 Lepidine................... 315 Cryptidine................. 315 PAGE Pyrrole.................... 316 Pyrrole-Red................ 316 Pyromucic Acid............316 Tetrol..................... 317 Furfurole.................. 317 Alkaloids.................... 317 Conine...................318 Azoconhydrine............ 318 Conylene ................. 318 Paraconine................ 319 Nicotine................... 319 Sparteine.................. 320 Opium Bases............... 320 Morphine..................320 Apomorphine..............321 Codeine.................... 321 Narcotine.................. 322 Cotarnine..................322 Meconine.................. 322 Opianic Acid.............. 322 Hemipinic Acid............ 322 Meconic Acid.............. 322 Comenic Acid..............322 Pyromeconic Acid.......... 322 Cinchona Bases............. 323 Quinine................... 323 Salts of Quinine............323 Cinchonine................324 Quinidine.................. 324 Cinchonidine............... 324 Cusconine.................. 324 Arieine.................... 324 QuinicAcid................ 324 Chinovic Acid.............. 325 Chinovin.................. 325 Quinotannic Acid........... 325 Chinchona-Red............. 325 Strychnine................. 325 Brucine................... 325 Atropine................... 326 Tropine................... 326 Tropic Acid................ 326 Hyoscyamine............... 326 Aconitine.................. 327 Veratrine.................. 327 Jervine.. ................. 327 Berberine.................. 327 Hydroberberine............327 Pi'perine................... 327 Piperinic Acid.............327 Methylpiperidine.......... 328 XX CONTENTS. PAGE Ethylpiperidine............328 Benzoyl piperidine.......... 328 Eserine.................... 328 Sinapine................... 328 Lycine....................328 Curarine................... 328 Harmaline................. 328 Harmine................... 328 Cocaine.................... 328 Colchicine................. 329 Corydaline................. 329 Chelidonine................ 329 Emetine................... 329 Solanine................... 329 Solanidine.................329 Glucosides................... 329 Amygdalin................ 329 Salicin...............:.... 330 ^sculin.................. 330 JSsculetin................. 330 Daphnin................... 331 Phloretin.................. 331 Daphnetin................. 331 Phloridzin................. 331 Phloretin.................. 331 Phloretic Acid............. 331 Quercitrin................. 331 Quercetin.................. 331 Quercetinic Acid........... 331 Hesperidin................. 331 Hesperitin................. 331 Hesperitinic Acid..........331 Arbutin................... 331 Myronic Acid.............. 331 Myrosin................... 331 Convolvulin................ 332 Convolvulinol.............. 332 Jalapin....................332 Jalapinol................... 332 Saponin................... 332 Sapogenin................. 332 Helleborin................. 332 Helleborem................. 332 Helleboresin............... 332 Helleboretin................ 332 Glycyrrhizin............... 332 Glycyrrhetin............... 332 Digitalin................... 332 Digitalretin................ 332 Coloring Matters............. 332 Chromogenes...............333 PAGE Dyeing.....................333 Bleaching.................. 333 Lichen-Colors.............. 333 Orsellie Acid...............333 Orcein, Lichen-Red......... 333 Orsellinic Acid............. 334 Evernic Acid............... 334 Erverninic Acid............ 334 Usnic Acid................. 334 ErythricAcid............. 334 Picroerythrin..............334 Vulpinic Acid.............. 335 Haematoxylin............... 335 Haematein..................335 Santalin....................335 Brasilin................... 335 Brasilem.................. 335 Carthamin................. 335 Polychroit................. 335 Crocin..................... 336 Curcumin.................. 336 Carminic Acid.............. 336 Carmine-Red............... 336 Ruficoccin................. 336 Nitrococcusic Acid......... 336 Chlorophyll................ 337 Bitter Principles.............. 337 Aloin...................... 337 Chrysammic Acid........... 337 Alorcinic Acid.............. 337 Santonin................... 337 Santonic Acid.............. 337 Picrotoxin................. 337 Cetrarin................... 338 Quassiin................... 338 Absynthin................. 338 Cantharidin................ 338 Cossin..................... 338 Betulin.................... 338 Carotin....................338 Chrysin................... 338 Ostruthin.................. 339 Peucedanin................ 339 Oreoselon.................. 339 Cascarillin................. 339 Columbin.................. 339 Smilacin................... 339 Biliary Substances............339 Glycoeholic Acid........... 339 Dyslysin................... 340 Cholic Acid................ 340 CONTENTS. xxi PAGE PAGE ... 340 347 Hyoglycocholic Acid... ... 340 Oxyneurin................. 347 Hyotaurocholic Acid.... .... 340 Albuminoids............... 348 Hyocholic Acid........ ... 340 349 .... 341 Glue....................... 349 ... 341 Glutin..................... 349 .... 341 319 .... 341 Chondroglucose............. 849 .... 341 349 ... 341 Mucin..................... P49 ... 341 350 .... 342 Silk Fibrin................. 350 ...342 351 ... 342 Estimation of Carbon and Hy- .... 343 351 .... 344 355 ...344 Estimation of Chlorine, Bro- .... 344 357 ...344 Estimation of Sulphur and Phos- .... 344 357 .... 344 Determination of Vapor-den- .... 344 sity....................... 358 ...344 Analytic Method of Determin- ... 345 ing the Constitution of Corn- Fibrin................. .... 345 363 .... 345 Synthetic Method of Determin- ... 345 ing the Constitution of Com- .... 345 366 .... 345 372 .... 346 373 .... 346 Action of Reagents on Organic Vitellin................ .... 347 375 .... 347 380 INTRODUCTION. Ever since the composition of substances first began to be known, and to be used as a means of classification, compounds which contain carbon have been considered apart from those containing the other elements. This was partly because the number of the carbon compounds was so enormous, but chiefly because those which occur in nature were, with a few excep- tions, produced by the vital processes of vegetable and animal liie. All attempts to reproduce them from their elements failed. It was therefore supposed that it was impossible to pro- duce them artificially, and that they were formed in organic nature by the influence of some mysterious force, which was called vital force. Hence the name, organic chemistry. Since that time multitudes of such substances have been produced from their elements, and the assumption of a vital force has long ago been given up, but the name remains in use. It is termed more correctly the chemistry of the carbon compounds. The carbon compounds which occur in nature contain, be- sides carbon, only a few elements, viz., hydrogen, oxygen, and nitrogen. Some contain also sulphur and phosphorus. By chemical means, however, almost all the elements have been introduced into carbon compounds. To understand the naturo of a compound, it is necessary, first of all, to know of what elements it is composed, and in what relative amounts they are present. In studying or- ganic compounds, therefore, the first step is to make a quali- tative and quantitative analysis of them. As the methods 1 2 INTRODUCTION. of qualitative and quantitative testing are usually the same, only the latter will be noticed here. The details of the oper- ations will be given in the Appendix. Carbon and hydrogen are always determined in one operation. A weighed amount of the substance is heated with an oxygen compound which gives up its oxygen easily at a high temperature, as cupric oxide or plumbic chromate. The carbon is oxidized to carbonic acid, and the hydrogen to water. This operation is called combustion. The water is absorbed in an apparatus containing fused calcium chloride, the carbonic acid in one filled with a solution of potassium hydroxide. By weighing the pieces of apparatus before and after the combustion, the weights of the water and carbonic acid absorbed are ascertained, and from them the the amounts of hydrogen and carbon are calculated. Oxygen is not estimated directly, but is calculated as the difference between 100 per cent, and the sum of the per cents, of all the other con- stituents. Nitrogen is estimated in two ways. (1.) By decomposing the substance in such a way that the nitrogen is given off as a gas. The gas is collected over mercury, and from its volume its weight is calculated, allowance being made for the temperature and pressure. (2.) The de- composition is so conducted that the nitrogen is converted into ammonia, the amount of which is estimated. Chlorine, bromine, and iodine are combined with silver and estimated as silver chloride, bromide, or iodide, after destruction of the organic sub- stance by ignition with caustic lime, or by oxidation at a high tempera- ture with fuming nitric acid. Sulphur and phosphorus are converted into sulphuric and phosphoric acids by oxidation of the organic substance (ignition with a mixture of potassium nitrate and sodium carbonate, or digestion with fuming nitric acid). The sulphuric acid is estimated as barium sulphate, the phosphoric acid as ammonio-magnesium phosphate. When the relation of the amounts of all the constituents of an organic compound have been determined by the foregoing methods, the numbers representing the per cents, form the first step toward determining the chemical formula of the compound. If the number representing the per cent, of each element is divided by the atomic weight of the same, the re- lation of the elements to each other is obtained. INTRODUCTION. 3 Suppose, for instance, a substance composed of carbon, hydrogen, and oxygen is found on analysis to contain 40 per cent, of carbon, 6.6 per cent, of hydrogen, and 53.4 per cent. of oxygen. Dividing by the atomic weights we have °=§=" H = *« = 6.6 0 = ^ = 3.3 i.e., for every 3.3 atoms of carbon there are 6.6 atoms of hy- drogen and 3.3 atoms of oxygen. It is at once evident that the relation of carbon to hydrogen and oxygen is 1:2:1. Hence the compound contains for one atom of carbon two atoms of hydrogen and one atom of oxygen, or CH80. The formula thus obtained by no means expresses, in every case, the true chemical formula of the substance. It shows only the relation of the single atoms to each other. There is a great number of compounds in which the atomic ratio 1C : 2 H : 1 0 exists. One of them is a gas at ordinary tem- peratures, others are liquids, some are solids, and further, the liquids and solids differ greatly among themselves both in chemical and physical properties. But all of these compounds do not possess the same molecular weight, that is, all do not contain in a molecule only one atom of carbon, two atoms of hydrogen, and one atom of oxygen. In some cases a molecule contains two atoms of carbon, four atoms of hydrogen, and two atoms of oxygen, or double the simplest relation, in others treble, and so on. Hence it becomes the task of the chemist, as soon as he has found out the percentage composition of a compound, and thereby ascertained the relation of the atoms to each other, to determine the molecular weight. There are various methods for doing this. 4 INTRODUCTION. If the compound is a gas, or can by elevation of the tem- perature be brought into the state of a gas without decomposi- tion, it is only necessary to determine the v/eight of a certain volume of the gas to ascertain the molecular weight; for, as is well known, the weights of equal volumes of different gases at the same temperature and same barometric pressure are in the same relation as their molecular weights, because equal volumes of gases always contain an equal number of mole- cules, no matter how different the gases may be. If, then, the weight of a volume of hydrogen is equal to two (since the weight of a molecule of hydrogen equals two), the weight of a volume of chlorhydric acid gas will be 36.5 (H = 1 + CI = 35.5), or if we take a volume of hydrogen as equal to one, the 36 5 weight of an equal volume of chlorhydric acid gas will be —~ = 18.25. A volume of chlorhydric acid gas weighs, then, 18.25 times as much as an equal volume of hydrogen, weighed of course at the same temperature and pressure. Hence if we did not know what the molecular weight of chlorhydric acid was, but had found that it was 18.25 times heavier than hydrogen—in other words, we had estimated its weight by volume—it would only be necessary to multiply this volume-weight by two to obtain its molecular weight. The molecular weight of a sub- stance is always twice as great as its volume-weight referred to hydrogen as unity. If we had, then, a substance, the simplest formula of which, according to analysis, was CH20, and it was found that its volume-weight = 30, we would know that its molecular weight would be 30 x 2 = 60. But the weight of a substance whose formula is expressed by CH80 is C + 2 H + 0 = 12 + 2 + 16 = 30. Hence the weight of our substance must be twice as great as CH20, that is, 2C -f- 4H + 20 = C3H402. Let us assume we had found that a substance whose sim- plest formula was CH20, gave a volume-weight of 45. The INTRODUCTION. 5 molecular weight would be 45 x 2 = 90, or three times as great as the formula CH„0, that is 03H603. The methods of estimating the gaseous volume, or, as it is generally termed, the determination of the vapor density, of substances which are solid or liquid, at ordinary temperatures, will be described in the Ap- pendix. When the compound is a base or an acid, the molecular weight can be estimated by analyzing a salt of it and calcu- lating the ralation of the atoms to each other. Acetic acid, for instance, is a substance which has the atomic relation just mentioned, CH20. It is an acid and dissolves silver oxide, forming a crystalline compound, silver acetate, which con- tains Carbon = 14.4$ Oxygen = 19.1$ Hydrogen = 1.8$ Silver = 64.7$ If these numbers are divided by the atomic weights of the corresponding elements, we have 14.4 ° = TT We see at once that the relation of the silver to the carbon is as 1 :2, to the hydrogen as 1:3, and to the oxygen as 1 : 2. Hence in this compound, for one atom of silver there are two atoms of carbon, three atoms of hydrogen, and two atoms of oxygen, or AgC2H302. We know, however, that silver replaces one atom of hydrogen in acids. Keplacing the atom of silver by an atom of hydrogen, we have C2H402, which is the molecular formula of acetic acid. In a similar manner organic substances of a basic nature can be examined. Such bodies unite directly with acids, so that by determining the amount of acid with which they unite, the molecular weight of the compound can be calculated. If, on the other hand, the = 1.2 = 1.8 0 19.1 16 1.2 * = £ = « 6 INTRODUCTION. substance is neither basic nor acid, and cannot be brought into the gaseous state without suffering decomposition, then only an accurate study of its chemical metamorphoses will lead to the determination of its molecular weight. The formula which is deduced from the chemical composi- tion and the molecular weight does not so characterize a substance that confusion with others is impossible. There is a great number of compounds which possess the same com- position and molecular weight, but which differ greatly in chemical and physical properties. There are, for instance, five substances to whose composition and molecule the formula C3H60 corresponds. The differences between these five com- pounds can only arise from differences in their internal struct- ure, or constitution. Whenever their relations do not show beyond a doubt which of the five substances is meant, it becomes necessary to express the structure, or constitution, in the formula. In this way, what are called constitutional (graphic, glyptic, structural) formulas have come into use. To obtain a clear idea of constitutional or structural for- mulas, we must review certain laws which have already been mentioned in inorganic chemistry, but, owing to the simplicity of their relations in that branch of science, have not received the attention that they here require. SUBSTITUTION. Carbon is tetra-valent. Its tetra-valence and the replace- ment, or substitution, of the elements by each other in equi- valent amounts, form the foundation on which the most complicated compounds are built up. The mono-valent hydro- gen can be replaced atom by atom by the equally mono-valent chlorine, bromine, iodine, potassium, or silver. One atom of chlorine can take its position in the place of one atom of hv- drogen. It occupies the same position as its predecessor, and the equi-valence, or equilibrium, of the compound, which has INTRODUCTION. 7 been disturbed by the exit of the atom of hydrogen, is restored by the introduction of the atom of chlorine, which has the same binding power, or valence, as the atom of hydrogen, being equal to one. An atom of hydrogen can also be substituted by an equi-valent amount of oxygen; but since the atomic binding power of oxygen is twice as great as that of hydrogen, as seen in the compound H20, one atom of hydro- gen could be replaced by only half an atom of oxygen. Half an atom of oxygen, however, cannot be imagined and does not exist, so we must say, more logically, that an atom of hydrogen can be substituted by half the atomic binding power of an atom of oxygen, in which case the other half must be kept in equilibrium by some other energy equal to that of the hydro- gen, or one. To simplify matters, let us take up some illus- trations. To represent the degree of the atomic binding power, or valence, we shall use a small stroke near the symbol. One stroke expresses unity. H" "0" N -C- y. \ ' Mono-valent Di-valent Tri-valent Tetra-valent The simplest carbon compound is composed of one atom of carbon and four atoms of hydrogen : H H-C-H I H In this compound an atom of hydrogen can be substi- tuted by an atom of chlorine, bromine, iodine, potassium, etc. H H H H H-C-Cl; H-C-Br; H-C-I; H-C-K H H H H Again, an atom of hydrogen can be substituted by the half INTRODUCTION. of the atomic binding power of oxygen, the other half being satisfied by some other mono-valent atom, as H H H-C-O-K 1 H and H-C-O-H H We see then that the group ~0~K, or "OK, and ~0~H, or "OH, can substitute an atom of hydrogen in the same man- ner as a mono-valent atom. It is not remarkable, therefore, that in the group CH3 an unsatisfied bond, or valence, is free and active, and can only be rendered inactive by an equally great energy. H H-C- H It makes no difference if this energy is the entire attractive power of a single atom of a mono-valent element, or the re- mainder of all the active attractive energies of an atomic group, so long as its amount is equal to one. Proceeding in the same manner, an H can be substituted by the group NHa which is also mono-valent, or by the group CH3: H H HH H-C-N and H-C-C-H H XH HH The last formula CH3"CH3 brings us to a new carbon series, in which all the substitutions can be effected in the same manner as with the simple CH4. We shall, however continue with the first example, CH4. So far, only one atom of H, in the group CH4, has been sub- stituted by a mono-valent atom, or atomic group. In the same INTRODUCTION. 9 manner, two atoms of H can be substituted by two mono- valent atoms, or atomic groups ; or by one di-valent atom, or atomic group. 1) 2 H's by two mono-valent atoms : H H H H H-C-Cl; H-C-Br; H-C-I; H-C-Br; I I I I CI Br I CI (CH2C12) (CH2Br2) (CH2I2) (CH2BrCl) 2) 2 H's by one di-valent atom : H H H-Cn ; H-C-n etc. Lo U (CH2=0) (CH2=S) 3) 2 H's by one di-valent atomic group : H H H-C-j ; H-Cn L-N-H Lq-H I H (CH8=NH) (CH2=CH2) Further, three atoms of H in the CH4 can be substituted by three mono-valent atoms, or atomic groups; or by one mono-valent and one di-valent atom, or atomic group ; or by one tri-valent atom, or group. H H H HH ci-c-ci 01—6=6 (W c=c i Cl (CHC13) (CHC10) (CHN) (H2Ca) Finally all four of the H's can be substituted by four mono- valent atoms, or groups; or by one di-valent and two mono- 10 INTRODUCTION. valent atoms, or groups ; or by two di-valent atoms, or groups; or by a tri-valent and a mono-valent atom, or group. CC14; COCl2; C02 5 CN CI. We shall meet later a great number of substitutions. Here, however, it is only necessary to keep in view the principle that only equi-valent amounts, or equal worths, of atoms can re- place each other. Let us consider one of the examples just noticed, viz., the substitution of one of the atoms of H in the group CH4 by the mono-valent group CH3, or, HH H-C-C-H I I HH or CH3"CH3, C2H6. In this compound, which is more complicated than the pre- ceding CH4, the same substitutions can be effected as in the group CH4. The number of the substitutions derived, how- ever, will be greater. We shall also meet with substances which have the same composition, but totally different prop- erties. If in the group CH3"CH3, an atom of H is substituted by a mono-valent atom, or atomic group (for the sake of simplic- ity we shall again choose chlorine), the compound CH3~CH2C1 is formed. There is but one such compound. It is im- material whether we write CH3"CH2C1 or CH2CrCH3, be- cause the various atoms of hydrogen in the group CH3~CH3 act in an entirely equal manner. t No matter where the atom of chlorine is substituted, it occupies the same position in relation to the carbon and hydrogen in space. Hence there is only one compound possible which has the composition C2H5C1 or CH3"CH2C1. It is different, however, when a second H is substituted by a chlorine atom. There are now two cases possible. The second chlorine atom replaces an atom of INTRODUCTION. 11 hydrogen belonging to the carbon atom which already possesses a chlorine atom, thus forming the compound CH3~CH Cl2, or it substitutes an atom of hydrogen belonging to the other carbon atom, and the compound CH2C1~CH2C1 arises. The relations are seen at once in the constitutional formulas: H H H H 01-6-6-01 H-6-6-C1 il ll H H H CI Here we have two compounds which have absolutely the same molecular weight, but yet must possess totally different properties because the different relative positions of the chlo- rine atoms influence the properties of the compound in a most marked manner. Such compounds, possessing the same composition and mole- cule, but presenting differences in properties, are called isomeric. The great number of isomeric compounds has compelled the chemist to examine deeply into the structure or constitution of them ; for, as has just been observed, in this case, only the dissimilarity of constitution can occasion differ- ences in properties. A similar case of isomerism presents itself when the group CH3"0H3 contains three chlorine atoms. It is seen at once that there are two modifications possible, CH2C1"CH Cl2 and CH3~C 013. A third compound is not possible. All the hydrogen atoms can successively be substituted by chlorine atoms or other elements, or atomic groups. The only other case that we shall examine, however, is the substitution of a hydrogen atom by the mono-valent atomic group CH3, by which the compound CH3"OH2"CH3 is obtained. If the same substitution be continued in this compound we shall obtain either CH3-CH2"CH2-CH3 or CH3"CH-CH3, both 6n, C4H10. They are isomeric because in the one case the car- 12 INTRODUCTION. bon atoms hang together like a chain, while in the other the three carbon atoms are bound to one : H HHH h-6-] H-C-C ^-H H I H —c—6- HHH H-C-C-C-H HHH By substitution of CH3 in these two compounds we obtain, 1) CH3-CH2-CH2-CH2"CH3 ; 2) CH3_CH2-CH-CH3 = C2HS"CH"CH3; CH3 6h3 CH3 3) CH3-6-CH3 CH3 All = C5H13. In this case there are three isomers. With the compound C6H14 the number will be much greater. With the increas- ing number of carbon atoms, the number of isomers increases with extraordinary rapidity according to the laws of permu- tations. These compounds consisting only of carbon and hydrogen are called hydrocarbons. Placing them in a series, it is at once noticeable that each member differs from the preceding one by an increment of CH2. If we represent the number of carbon atoms by n (n being any whole number from 1 on), then th» number of H atoms is 2n + 2. The series, there- fore, possesses the general formula CnH2„ + 2. If we start out from the compound CH2=CH2, that is, one in which the carbon atoms are held together by two bonds, and substi- tute in this, as before, an atom of hydrogen by the group CH3, we shall have CH2=CH"CH3, or C3H6. Continuing in the INTRODUCTION. 13 same manner, we can substitute another hydrogen atom by a CH3, obtaining CH2=CH_CH2~CH3 and CH2=C"CH3, both CH3 C4H8. Proceeding in this manner the following series is obtained : C2H4 ; C3H6 ; C4H8 ; C5H10. These compounds have the general formula C„H2n, in which n denotes any whole number from 2 on. A body CH2 is not known, and from the tetra-valence of carbon is not probable. Two carbon atoms held together by three bonds give CH^CH, or C2H2. By substitution of this we get CH=C"CH3 = C3H4, so that another series of hydrocarbons can be built up, C2H2; C3H4 ; C4H6, etc., which fall under the general formula CKH8»-2, the smallest value of n being again 2. Series of which each member is derived from the preceding member by the replacement of an H by a CH3, are called homologous. All compounds having the general formula C„H2„, C„H3n_2, etc., can be converted into those of the formula C„H2„ + 2; that is to say, by the addition of hydrogen the double and treble binding of the carbon atoms can be broken until only the single binding remains. Hydrocarbons which are capable of taking up more hydrogen are termed unsaturated, or unsatis- fied compounds. Those of the series CnH2nf2, not being able to take up any more hydrogen, are called saturated com- pounds. C2H4 = CH2=CH2 can take up two more atoms of hydro- gen, passing into C2H6 = CH3"CH3. In the same manner, C2H2 = CH=CH by combining with four atoms of hydrogen forms C2H6 = CH3"CH3. 14 INTRODUCTION. We shall now proceed to the study of the individual organic compounds, taking up first those which contain only one atom of carbon, or derivatives of the hydrocarbon CH4; then those containing two atoms of carbon linked together, or derivatives of the hydrocarbon C2H6 ; and after them the derivatives of 03H8, and so on. Ct GROUP. Methane Compounds. Methane, Methyl Hydride, Marsh Gas, Fire-Damp ; CH4. This compound, which is the simplest of the hydrocarbons, is found in marshes and coal mines (fire-damp). It is formed by the slow decomposition of organic substances in the absence of air. At some places it streams from the earth (at Baku); petroleum gases contain it. It is produced by the dry distil- lation of many organic substances, and forms an important constituent of illuminating gas. Methane is made by heating a mixture of sodium acetate with an excess of sodium hydroxide : C2H3Na02 -f NaOH = Na2C03 + CH4. Sodium acetate Sodium carbonate It can also be made synthetically by leading hydrogen sulphide and carbon disulphide over red-hot metallic copper : CS2+2H2S + 4Cu8 = CH4+4Cn2S. Carbon disnl- Cuprons sul- phide Phlde It is a colorless and odorless gas, which condenses to a liquid at a very low temperature and under a very great press- ure. The volume-weight of the gas = 8 {i.e., it is eight times heavier than hydrogen). Its molecular weight = 16. It is easily combustible, burning with a scarcely luminous flame to carbonic acid and water. When mixed with air or oxygen it forms an explosive mixture : 16 Ct GROUP.—METHANE COMPOUNDS. CH4 + 202 = C02 + 2H20. This mixture constitutes the dangerous " fire-damp" of the coal mines, and has caused many frightful explosions when ignited by the miners' lamps. The introduction of the Davy safety-lamp has, however, greatly reduced the danger of its presence. By exposing a mixture of equal volumes of methane and chlorine to diffused light, the first chlorine substitution of methane is obtained: CH4 + Cl2 = CH3C1 + HC1. Halogen Substitutions. I. One H of the Methane is substituted by a Halogen. (Alkyl-halogens, or Alkylogens.) Methyl Chloride, Ghlormethyl, Mono-chlor-methane, CH3C1, does not occur in nature. It is usually made by the action of nascent chlorhydric acid on methyl alcohol: CH40 + HC1 = CH3C1 + H20. Methyl alcohol Methyl chloride A mixture of methyl alcohol, salt, and sulphuric acid is heated, and the resulting product caught over water. Colorless gas with a pleasant odor and sweet taste. Con- denses in a freezing mixture to a liquid which boils at — 21°. Vol. wgt. = 25.25. Mol. wgt. = 50.5. Methyl Bromide, Brom-methyl, Mono-brom-methane, CH3Br, is obtained from methyl alcohol and gaseous or nascent bromhydric acid : CH40 + H Br = CH3Br + H20. METHYL IODIDE. 17 Bromine is allowed to drop into cooled methyl alcohol containing amorphous phosphorus.* Colorless liquid with a pleasant odor, boiling at 5°. Vol. wgt. = 47.5. Mol. wgt. = 95. Methyl Iodide, Iodomethyl, Mono-iodo-methane, CH3I. From methyl alcohol and gaseous or nascent iodohydric acid. CH40 + HI = CH3I + H20. A solution of iodine in methyl iodide is added gradually to boiling methyl alcohol containing phosphorus. Colorless liquid with a pleasant odor, boiling at 44°. Ex- posed to the light, it becomes yellow to red from a partial decomposition. Vol. wgt. = 71. Mol. wgt. = 142. II. Two H's of the Methane are substituted by Halogens. Methylene Chloride, Dichlor methane, CH 2 CI2. It is formed, together with CH3C1, by the action of chlorine on methane. Also from chlorine on methyl chloride. But little known. Methylene Bromide, Dibrom-methane, CH2Br2, and Methylene Iodide, Di-iodo-methane, CH2I2. As these three compounds are produced with difficulty, and have been as yet but little examined, they are only interesting as members of the series. * The compounds of phosphorus with chlorine, bromine, and iodine, PC13, PBr3, PI3, are decomposed by water into chlorhydric, bromhydric, and iodohydric acids. PC13 + 3 HOH = P(OH)3 + 3 HC1 PBr3 + 3 HOH = P(OH)3 + 3 HBr PI3 + 3 HOH = P(OH)3 + 3 HI. The alcohols act in exactly the same manner, except that the organic rests unite with the chlorine, bromine, or iodine. These reactions will be more fully considered later on. 2 18 C, GROUP.—METHANE COMPOUNDS. Methylene iodide is made from iodoform by the action of strong iodo- hydric acid in presence of phosphorus : CHI3 + HI = CHJ2 + I2. Iodohydric acid sometimes substitutes retrogressively, i.e., introduces hydrogen. Phosphorus is added to unite with the iodine as it becomes free, forming phosphorus tri-iodide, which, by decomposition with the water, yields fresh iodohydric acid. III. Three H's of the Methane are substituted by Halogens. (Forms.) Chloroform, Trichlormethane, CHC13, is also a product of the action of chlorine on methane : CH4 + 3 Cl2 = CHC13 + 3 HC1. It is made by the action of calcium hypochlorite (chloride of lime) on dilute alcohol. 1 part of chloride of lime, 4 parts of water, and ^ part of alcohol of 0.85 sp. gr., are heated quickly until the reaction begins, and the heat then removed. Chloroform distils over mixed with water, from which it is afterwards separated, dried, and redistilled. The reaction takes place in two steps. By the action of chlorine on alcohol, chloral is first formed, but is decomposed into chloroform by the lime. C2H„0 + 4C12 = C2HC130 + 5HC1. Alcohol Chloral 2C2HC130 + Ca(OH)2 = 2 CHC13 + Ca(CH02)a. Chloral Chloroform Calcium formate Chloroform is a colorless mobile liquid with a pleasant odor and sweet taste. Its specific gravity at 0° is 1.525, at 17°, 1.491. It boils at 62°. It burns difficultly, with a green-edged flame. It is very little soluble in water, but imparts its taste and odor to it. Easily soluble in alcohol and ether. When pure, it sinks in water without causing a troubling ; but if it contains alcohol, the water above remains troubled for a long time. By digestion with alcoholic potassium hydroxide it is decomposed into potassium formate and chloride : BROMOFORM. —IODOFORM. 1(J CHC13 + 4 KOH = CH02K + 3 KC1 + 2 H80. Potassium formate Ammonia, in presence of potassium hydroxide, converts it into potassium cyanide and chloride : CHC13 + NH3 + 4 KOH = KCN + 3 KC1 + 4 H20. Potassium cyanide It is used in medicine as an anaesthetic. For this purpose it must be perfectly pure and dry. It must be clear and transparent, not troubled (moisture). It must have the correct specific gravity and boiling point (contamination with alcohol and foreign chlorides). It must not redden litmus paper or cloud a silver nitrate solution (free chlorhydric acid), and should give no precipitate of potassium chloride with an alcoholic potassa solution (foreign chlorides). For the production of chloroform for medicinal purposes, only a pure alcohol, free from fusel oil, should be used. In the arts, chloroform is used as a solvent for bromine, iodine, alkaloids, phosphorus, rubber, resins, etc. Bromoform, Tri-brom-methane, CHBr3. Bromine is added to a solution of one part of potassium hydrate in one part of ethyl alcohol until a yellow color remains. The under layer of oil is bromoform. It is a colorless liquid with an odor similar to that of chloro- form. B. p. 152°. Sp. gr. at 12° = 2.9. Iodoform, Tri-iodo-methane, CHI3, two parts of sodium car- bonate are dissolved in ten parts of water, and one part of alcohol is added, the whole warmed to 60-80°, and one part of iodine gradually added. Yellow crystalline leaflets or tablets with an odor like saf- fron, fusing at 119°. It cannot be distilled in the dry state without partial decomposition. Quite easily soluble in alcohol and ether. Its use in medicine depends on its large content of iodine. It acts like iodine, but more mildly. 20 Cj GROUP.—METHANE COMPOUNDS. IV. Four H's of the Methane are substi- tuted by Halogens. . Carbon Tetrachloride, Tetra-chlor-methane, CC14. Tetrachlormethane is the final product of the action of chlo- rine on methane, methyl chloride, and chloroform. It is usually made from the latter. It is a colorless liquid with a pleasant odor, boiling at 78°. It is decomposed, by digestion with alcoholic potash, into potassium carbonate and chloride : CC14 + 6 KOH = K2C03 + 4 KC1 + 3 H20. All of these chlorides, etc., when treated with nascent hydrogen, suffer a retrograde substitution, and yield methane. Sodium amalgam is a compound of mercury and sodium, which decomposes water slowly, giving a continuous evolution of hydrogen. If the chlorides, etc., are treated with sodium amalgam and water, methane will be obtained as the final product. CH3C1 + H3 == CH4 + HC1 CH2C12 + 2 H3 = CH4 + 2 HC1 CHC13 + 3 H2 = CH4 + 3 HC1 CC14 + 4H2 = CH4 + 4HC1. General reactions of the Chlorides, Bro- mides, and Iodides of the Hydrocarbons. On account of the ease with which they exchange their halogen atoms for other mono-valent atoms, or atomic groups, the chlorides, bromides, and iodides of the hydrocarbons (alkylogens) serve as starting-out points for the production of other organic compounds. The study of them is hence very important. (1) By digestion with sodium or potassium hydroxide, the halogen is substituted by OH, hydroxyl : CH3I + KOH = CH3(OH) + KI. Methyl alcohol CARBON TETRACHLORIDE. 21 In the higher carbon series, potassic hydroxide generally splits out HC1, HBr, or HI from the alkylogens, and pro- duces a hydrocarbon, or a derivative of a hydrocarbon, of the series C„H2„. This decomposition takes place particularly when one or more hydrogen atoms are substituted by halogens : 1) CH3-CH2_CH2I + KOH = KI + H20 + CH3-CH=CH3 or CH3-CH.rCH2I = HI + CH3-CH=CH2 2) CH2Br_CH3Br + KOH = KBr + H20 + CHBr=CH3 CH2Br_CH2Br + 2 KOH = 2KBr + 2H20 + CH=CH. This procedure may be represented as taking place in two steps. In the first, the halogen is replaced by a hydroxyl group, CH3Br-CH2Br + KOH = CH2BrCH*(OH) +KBr, this then combines immediately with a hydrogen atom of the neighboring carbon atom, thus occasioning the double binding of the carbon atoms : CH2Br"CH2(OH) = CHBr=CH2 + H30. 2) With potassium sulphhydrate, the halogen is substituted by SH, sulphuryl : CH3I + KSH = CH3(SH) + KI. Methy l-mcrcapt an 3) Ammonia effects the substitution of NH2, amidogen, (amide, amine) for the halogen : CH3I + NH3 = CH3(NH2) + HI. Methylamine 4) With metallic zinc, the zinc compound of the hydro- carbon is formed : 2 CH J + 2Zn = SS'^Zn + ZllI8- L31 f OM1U. — QJT 1/ 5) With sodium alkoxide, the ethers are formed : CHJ + CH3ONa = CH3"0"CH3 + Nal. Sodium mcthoxide Mothyl-cther 22 C1 GROUP.—METHANE COMPOUNDS. 6) With the sodium or silver salts of the organic acids, the esters, compound ethers, or organic salts of the acids are pro- duced : CH3I + CH02Na= CH3CH02 + Nal. Sodium formate Formic methyl- ester 7) With potassium cyanide, the cyanides are formed : CH3I + KCN = CH3(CN) + KI. 8) With potassium sulphocyanide, the sulphocyanides are produced : CH3I + KSCN = CH3SCN + KI. There is still a great number of reactions of which the alkylogens are capable, but the consideration of them would lead us beyond the limits of this work. These reactions usually take place by treating the chlorides, etc., with potassium and silver compounds. The halogen and the metal unite, while the two rests combined to a new molecule. XC1 + YAg = AgCl 4- XY. The alkylogens are all very reactive, the order in activity being iodides, bromides, chlorides. Hydroxyl Substitutions. The hydroxyl substitutions of the hydrocarbons are the most important compounds in organic chemistry, because they are of the highest significance in the phenomena of life, and in the arts, and also yield the chemist the material from which all other derivatives are either directly or indirectly produced. If an H in a hydrocarbon is replaced by a hydroxyl group (OH), an alcohol, or carbinol, is produced. If 2 H's belonging to one carbon atom are replaced by 2 OH's, a molecule of H20 splits off, and the remaining atom of 0 fills the gap. METHYL ALCOHOL. 23 CH3(OH) H H-CTOH OH Such bodies are called aldehydes, or ketones (the difference between these two classes of compounds will be explained further on). If a third atom of H is substituted by OH, another molecule of water drops out, and a compound is formed having instead of three hydroxyls the group 0 (OH), as, for instance, CHO (OH). H H HO_CrOH = HO-C-, + H20. 6h lo Such compounds are called acids. The substitution of a fourth H by OH could only take place in the methyl group, as in all other series it is replaced by hydrocarbon rests. In the methane series, in this case, two molecules of water split off : C(OH)4 = C02 +2H30. Methyl Alcohol, Carbinol, Wood Spirit, Methylated Spirit, CH3(OH) = CH40.' Methyl alcohol is produced with acetic acid in the distillation of wood. It occurs in combination with salicylic acid in the oil of wintergreen (Gaultheria procumbens). It is obtained from the aqueous distillate of wood, or crude wood vinegar. The product, which has been separated from the tar, is distilled over burnt lime several times down to about 10 %. Fused calcium chloride is then added. The crystalline compound of methyl alcohol and calcium chloride, which is obtained, is freed from all oily matters by washing with ether. Finally, the mass is distilled with water, which decomposes the compound. The methyl alcohol which is obtained in this manner, is = CH20 + H20 H = H_C-| + H20. Lo 24 Cx GROUP.—METHANE COMPOUNDS. dehydrated by distillation over burnt lime, but is not chemically pure. For most purposes it is, however, sufficiently pure. To obtain it absolutely pure, it is transformed into the crystalline oxalic ester, which is purified by repeated crystallizations, and distilled with water, which decomposes the compound. The aqueous alcohol thus obtained is freed from water by burnt lime and anhydrous cupric sulphate. Methyl alcohol is a colorless, aqueous, mobile liquid, with an odor and taste like that of ordinary alcohol. B. p. = G5°. Sp. gr. at 0° = 0.798. Gas vol.-wgt. =16, molecular wgt. = 32. It is soluble in all proportions in water, alcohol, ether, acetic acid, etc. Essential oils and all salts which are solu- ble in alcohol dissolve in it. It burns like alcohol. In the arts it is used as a solvent (varnishes), in the manu- facture of aniline colors, and for denaturalizing alcohol. General Properties of the Alcohols (Car- bin ol s.) 1) The alcohols on oxidation are converted into their corre- sponding aldehydes and acids. The mechanism of the reaction is as follows : A second, and then a third atom of hydrogen belonging to the same atom of carbon which holds the OH, is replaced by an OH, and in each case a molecule of water drops out: CH3OH + 0 = CH3(OH)2 CH2(OH)2 = CH30 + H20 Aldehyde further CH3(OH) + 02 = CH(OH)3 CH(OH)3 = CHO(OH) + H20, or Acid CH20 + 0 = CHO(OH) Aldehyde Acid 2) All alcohols give with phosphorus trichloride, phosphorus tribromide, and phosphorus tri-iodide, the simple chlor- ides, bromides, and iodides of the hydrocarbons (alkylogens) and phosphorous acid. The reaction is the same as with water, and, in fact, the alcohols may be regarded as Avater in which METHYL ALCOHOL. 25 an H has been replaced by the mono-valent hydrocarbon rest. For example, methyl alcohol is methylated water : H(OH) CH3(OH) Water Methyl alcohol 3H(0H) + PC13 =3HC1 + P(OH)3 3 CH3(OH) + PC13 = 3 CH3C1 + P (OH)3. 3) Alcohols dissolve sodium and potassium, forming solid compounds, which are very reactive, i.e., the K or Na is easily exchanged for other mono-valent atoms, or groups. In this case, also, the alcohols act in the same manner as water : HOH + Na = HONa + H Sodium hydroxide CH3OH + Xa = CH3ONa + H Sodium methoxide 4) With acids, the alcohols give up a molecule of water and form esters, or compound ethers (organic salts).* When acids possess several atoms of hydrogen substitutable by metals, are, in other words, polybasic, the resulting compounds, in which one or more of these replaceable H's are still present, are termed ester-acids. CH3(OH) + (HO)N02 = CH3ON08 + H20 Nitric acid Methyl nitric ester CH3(OH) + gg>S02 = CH!}g>02 + H20 Sulphuric acid Methyl sulphuric acid CH3(OH) + HO\Qft _CH30\on , 2HO CH3(OH) + HO/SO* = CHj0/S0* + 2 H2° Methyl sulphuric ester HO\ CHsO\ ch3(oh) + ho-)po = ho-^po + h80 ho/ ho/ Phosphoric Methyl phosphoric acid acid * It is better to consider them simply as salts, e.g., methyl nitrate, etc. 2G Ct GROUP.—METHANE COMPOUNDS. nrr /^ttx HO\ CH30\ Dimethyl-phosphoric acid CH3(OH) H0X CH30\ CH OH) + HO>0 =CH3O^PO + 3H20 CH OH HO/ CH30/ Methyl-phosphoric ester With gaseous chlor- brom- or iodohydric acid, the alcohols yield, there- fore, the chlorides, bromides, or iodides (alkylogens), 2 CH3(OH) -f- HC1 = CH3C1 + H20. 5) By warming with sulphuric acid, the alcohols yield their corresponding ethers, 2CH3(OH) = g^\>o + H20. The term ether is given to those compounds which consist of two hydrocarbon rests united by an atom of oxygen, in other words, organic oxides. Nearly all the reactions of the alcohols are easily explicable, when we assume that they behave in the same manner as the metallic hydroxides. For instance, methyl alcohol resembles KOH, potassium hydroxide. 1) The alcohols unite with the acids with loss of water to form esters. According to our assumption, then, these esters correspond to salts: a) CH3HO + HON02 = CH3ON0.2 + H20, Methyl nitrate KHO + HON02 = KON02 + H20 ; Potassium nitrate b) CH3HO + HC1 = CILC1 + H20, KHO + HC1 = KC1 + H20 ; c) CHsHO + §q^S02 = CIJf q^S02 + H20, Primary methyl sulphate d)2CH3OH + ho)>S02 = CH30/^0a +2H*°- Secondary methyl sulphate METHYL ALCOHOL. 27 With the polybasic acids, the alcohols form several series of salts. It is only when all the substitutable hydrogen atoms are replaced by alcohol (alkyl) rests, in our case, methyl, that the salt becomes neutral ; in all other cases the salts are acid, i.e., they still contain hydrogen which can be substituted by a metal. The compound formed in equation c (primary methyl sulphate) is a monobasic acid, for it possesses one substitutable H which can be replaced by K, N/a, etc., or by methyl, or any other alcohol (alkyl) rest. In the esters, or compound ethers, as in the oxygen salts, the alkyl rest is bound by means of oxygen to the element forming the acid (linking function), in methyl nitrate with nitrogen, in methyl sulphate with the sulphur. 2) The alcohols pass into the ethers, that is, their oxides, exactly as the metallic hydroxides pass into the oxides : CH3OH + CH3OH = CH3"0-CH3 + H20 Methyl oxide AgOH +AgOH =Ag"0"Ag + H20 Argentic oxide It is by no means necessary that both of the affinities of oxygen should be neutralized by the same atomic group. The second bond may be satisfied by the atom of a metal as well as by any alkyl rest: CH^'OH + Na = CH3"0~Na + H analogous to Sodium mcthoxide K_OH + Na = K_0-Na + H Potassium so- dium oxide CH-TOH + C.HrOH = CH3_0-C2H5 + H20 Methyl-ethyl oxide From these reactions we see that methyl alcohol behaves as a mono- valent base. Later on we shall meet alcohols which deport themselves as di- and poly-valent bases. Methyl alcohol dissolves sodium with considerable evolution of heat. The sodium substitutes an H of the hydroxyl : CH3OH + Na = CH3ONa + H. The resulting compound, CH3ONa, sodium methoxide, is a solid. Water decomposes it into sodium hydroxide and methyl alcohol : CH3ONa + HOH = CH3OH + NaOH 28 Cj GROUP.—METHANE COMPOUNDS. It yields the ether and sodium chloride with the chlorides, etc., of the alcohols (alkylogens) : CH3ONa + CH3C1 = CH3-0_CH3 + NaCl. Methyl alcohol, when treated with concentrated sulphuric acid, becomes highly heated, and the primary methyl sulphate, or methyl-sulphuric acid is formed, CH3HS04. This acid forms salts with metals because it contains an atom of substi- tutable H. If the mixture of alcohol and acid is distilled, the neutral methyl sulphate, or methyl sulphuric ester is obtained, (CH3)2S04. If, however, there is not a great excess of sul- phuric acid present (e.g., when there is one part of alcohol to four of acid), Methyl Oxide, or Methyl Ether (CH3)20, is formed. At ordinary temperatures it is a gas with a pleasant ethereal odor, becoming solid at — 23°. It is very inflammable, and easily soluble in water. All the ethers can be made in the same way as the methyl ether, either by heating the alcohol with concentrated sul- phuric acid, whereby a molecule of water is removed. This amounts to the formation of an anhydride, 2 CH3OH = CH3_0"CH3 + H20. Or by treating an alkylogen with the sodium compound of the alcohol (metallic alkyloxide): CH3C1 + CH3ONa = CH3_0"CH:J + NaCl. Ethers with different hydrocarbon rests, or mixed ethers, can be produced by this later method. Oxidation of Methyl Alcohol. By leading the vapors of methyl alcohol mixed with air over a glowing platinum spiral, methyl aldehyde is formed. It is also produced by replacing both of the atoms of iodine in methylene iodide by an atom of oxygen. This is effected METHYLALDEHYDE. 29 by transforming the iodide into methylene acetate by treat- ment with silver acetate, and decomposing the acetate with potassic hydroxide, CH2I2 + 2 C.H.O.Ag = CH2(C2H302)2 + 2 Agl. Silver acetate Methylene acetate CH2(C2H302)2 + 2 KOH = CH20 + 2 C2H302K + H20. Methylaldehyde, H"CHO, or CH20. This aldehyde at ordi- nary temperatures is properly a gas. Its molecules possess the peculiar property, however, of uniting among themselves to form a complicated molecule, a body which, at ordinary tempera- tures, is solid, and fuses at 152° ; at a higher temperature it is converted into vapor. This substance is called methyl-met-al- dehyde. If it is brought into the gaseous state, it is decom- posed into ordinary gaseous aldehyde. Such a fusion of several molecules is termed polymerization. If the oxidation is effected by stronger agents, as, for in- stance, with manganic di-oxide and sulphuric acid, platinum black, or potassium dichromate and sulphuric acid, the tri- hydroxylated substitution-product is obtained : CH3(OH) + 02 = CH(OH)3 = CHO(OH) + H20. Formic acid The aldehyde, CH20, as above stated, is formed from methylene hydroxide, CH2(OH)a, by elimination of water (dehydration), since two hydroxyls cannot exist bound to the same carbon atom. If instead of hydroxyls, the group "0~CH3 (methoxyl) be introduced, then stable com- pounds can be obtained having two, or even three, of these groups bound to one carbon atom. Thus methylene iodide with potassium hydroxide gives (indirectfy) methyl-aldehyde : 1) CH2I2 + 2 KOH = CH2(OH)2 + 2 KI; 2) CH2(OH)2 = CH20 + H20. Treated with potassium or sodium methoxide, however, it yields Methylene Dimethoxide, or Methylal : CH2I2 + 2 KOCH3 = CH2(OCH3)2 + 2 KI. 30 Cj GROUP.—METHANE COMPOUNDS. Methylal can also be obtained by carefully oxidizing methyl alcohol with manganic di-oxide and sulphuric acid. It is a liquid with a pleasant odor, boiling at 42% and soluble in 3 parts of water. Formic Acid, HCO(OH), CH202, occurs in nature. It exists in ants, in the needles of many pines, in nettles, etc. It is also a product of the decomposition of sugar, starch, gums, etc. In the animal organism it is contained in very small amounts in the blood and urine. It is formed by the oxida- tion of methyl alcohol; it is produced in the form of its potassium salt by the decomposition of iodoform, chloroform, and bromoform by means of potassium hydroxide ; also from cyanhydric acid. Synthetically, it can be formed from car- bonous oxide and potassium hydroxide. Generally it is made by the decomposition of oxalic acid in the presence of glycerol. The oxalic acid falls into carbonic acid and formic acid: C2H204 = C02 + CH202. Oxalic acid Equal parts of oxalic acid, dried at 100% and glycerine are heated at 110° until the evolution of gas (carbonic acid) ceases; water is then added to the oily mass, and the whole distilled. In this way, a dilute acid is obtained. The pure acid is produced by the decomposition of its lead salt by hydrogen sulphide, plumbic sulphide and formio acid being obtained. Formic acid is a colorless liquid with a penetrating odor and a strongly acid taste. It produces blisters on the skin. At 1° it solidifies to glittering crystals, which fuse at 8.6°, and boil at 99°. It is soluble in all proportions in water and alcohol. Its vapor is combustible. Owing to its tendency to become more highly oxidized, i.e., to carbonic acid, it takes oxygen away from easily reducible substances, acting, there- fore, as a reducing agent: CH202 + 0=C02+H20. It reduces, for instance, solutions of silver and mercury FORMIC ACID. 31 salts. Concentrated sulphuric acid decomposes it into water and carbonous oxide : CH202 = CO + H20. When heated with water formic acid forms a hydrate, CH,02 + H20, or CH(OH)3, Orthoformic acid, which boils at about 106\ •General Remarks on the Organic Acids. Formic acid may be considered as the prototype of all or- ganic acids. When we examine its constitution we find that the four valences of the carbon are satisfied in the following manner: One valence by an H, Two valences by an 0, and One valence by the group OH; H 0=C"0"H. The atom of H, which is united to the carbon, can be sub- stituted by any mono-valent organic group. The group may be a very complicated one, the only condition being that it must possess one free valence. On the other hand, the group COOH, which in formic acid is bound to an atom of H, can enter an organic compound as a mono-valent group, and form an acid. The group COOH is called carboxyl, and acids formed by its introduction are known as carbozylic acids. The hydrogen of the carboxyl group acts as the hydrogen of inorganic acids, being easily substituted by metals. It is the so-called basic hydrogen. As the carboxyl group contains only one atom of replaceable hydrogen, it is monobasic. Organic acids which contain only one carboxyl group are there- fore monobasic acids. If an organic acid contains two carboxyl groups, it is dibasic, etc. The number of carboxyl groups determines the 32 Cj GROUP.—METHANE COMPOUNDS. degree of basicity. Two simple examples will serve to illus- trate this. If, in formic acid, the atom of hydrogen which is bound to the carbon atom is replaced by the methyl group, CH3, the compound CH3"COOH (or C2H402), acetic acid, is formed. Acetic acid is a monobasic acid because it contains but one carboxyl group. If, on the other hand, the same atom of hydrogen is replaced by a carboxyl group, the com- pound COOH i (or CoHoO.), oxalic acid, COOH V 2 2 4 is formed. Oxalic acid is a dibasic acid because it contains two carboxyl groups. On comparing the empirical composition of formic acid with that of methyl alcohol, it will be found that it contains two atoms of hydrogen less, and one atom of oxygen more, than methyl alcohol. All acids contain two atoms of hydrogen less, and one atom of oxygen more, than the alcohols from which they are derived. The laws of substitution which have been mentioned find application in the acids. 1) The hydrogen of the carboxyl can be substituted by a metal forming a salt, as H"COONa, sodium formate. 2) The hydrogen of the carboxyl can be substituted by alcohol (alkyl) rests, forming esters, compound ethers, or organic salts : H"COO-(CH3) Methyl-formic ester. 3) The hydrogen of the carboxyl can also be replaced by an acid rest. An acid rest is an acid less OH. The rest of formic acid is CHO : H_CO(OKt) + H~CO(OH) = PI'CO. O.HCO + H20. Compounds formed in this manner are called anhydrides. FORMIC ACID. 33 Their constitution is analogous to that of the inorganic acid anhydrides : N02(OH) + N02(OH) =N02-0-N02 + H20 Nitric acid Nitric anhydride CHO(OH) + CHO(OH) = CHO"0-CHO + H20. Formic acid Formic anhydiide As the anhydride of formic acid is not yet known, this class of com- pounds will be considered under the next acid, acetic acid. 4) The hydroxl of the carboxyl can be replaced by CI. This derivative of formic acid, which would have the formula H~COCl, has not yet been obtained, because it decomposes at once into CO and HC1, but the reaction takes place with almost all the other acids. The compounds thus obtained are called aci-chlorides. The chlorine in them is remarkably easy of substitution by other mono-valent atoms, or atomic groups. They are decomposed by water, the hydroxl taking the place of the chlorine : CH3-CO-Cl + H20 = CH3-CO"OH + HC1. Acetyl chloride Acetic acid Ammonia affects the substitution of the CI by NH2 : CH3-CO"Cl + NH3 = CH3-CO"NH, + HC1. 5) The hydroxyl of the carboxyl can be substituted by the group NH2, H_CO"NH2, Formamide. 6) By distillation of the salt of an organic acid with an excess of alkali, the carboxyl group is split off and replaced byH: H"COONa + NaOH = HH + Na2C03 Sodium formate Sodium carbonate CH,'COONa + NaOH = CH4 + Na2C03. Sodium acetate Methane 7) By the distillation of an organic salt by itself, a carbon- ate is also formed, two molecules of the acid acting on each other. But, in this case, the two acids rest unite. We shall 3 34 Cj GROUP.—METHANE COMPOUNDS. » examine this reaction more carefully later on. From formic acid, methyl aldehyde is produced : H~COONa + H-COONu = Na2C03 + CH20. Sodiu m formate Methyl al dehyde There are also various other reactions which we shall have occasion to study. Among the s a 11 s of formic acid which are worthy of notice are the sodium salt, HCOONa; the lead salt (HCOO)2Pb, from which the pure acid is obtained ; and the ammonium salt, HC00NH4, which by rapid heating falls into cyanhydric acid and water : HCOONH4 = HCN + 2 H20. Formic acid is properly an anhydride acid formed from CH(OH)3 by elimination of water. Although the salts of this acid, the orthoformic acid, have not been produced, its esters are known. By the action of sodium methoxide on chloroform, the orthoformic methyl ester is produced, while by the action of sodium hydroxide on chloroform, only the ordinary formic acid is formed : CHC13 + 3 NaOCH3 = CH(OCH3)3 + 3 NaCl, CHC13 + 3 NaOH = CH(OH)3 + 3 NaCl, CH(OH)3 = CHO(OH) + H20. The final hydroxyl substitution-product of methane, into which formic acid has such a tendency to pass, is C(OH)4. As soon as this body enters the free state, two molecules of water are eliminated, so that the compound C02 is formed. (CH404 — 2H20 = C02.) If, however, it does not pass into the free state, but at least one atom of hydrogen is replaced by a metal, or hydrocarbon rest, the molecule of water is not split off, and a derivative of the compound CO(OH)2 or CH203 is formed. The compound C(OCH3)4, Orthocarbonic Methylester, how- CARBONIC ACID. 35 ever, is stable, and can be obtained by the action of sodium methoxide on carbon tetrachloride : CC14 + 4NaOCH3 = C(OCH3)4 +4NaCl. By the action of sodium hydroxide on carbon tetrachloride, however, besides sodium chloride, only sodium carbonate is produced. Carbonic Acid, C02. This acid and its salts have already been studied in inorganic chemistry. Substitution products of carbonic acid. Both hydroxyls of the hypothetical carbonic acid, CO(OH)2, are replaced by chlorine. Chlorcarbonous oxide, phosgen, chlorcarbonyl, COCl2, is formed by the union of chlorine and carbonous oxide in sun- light. It is a colorless gas with an unpleasant odor, which condenses in a freezing mixture to a liquid boiling at 8°. With water it is decomposed into carbonic acid and chlor- hydric acid : COCl2 + H20 = C02 + 2 HC1. Chlorcarbonous oxide being the chloride of carbonic acid, is an aci-chloride, and possesses all the properties mentioned as belonging to that class of compounds. If chlorcarbonyl is conducted into an alcohol, the corresponding chlorcarbonic ester is obtained : COCl2 + CH3OH = HC1 + CO^011* Chlorcarbonic methylester The chlorcarbonic esters exchange their chlorine very easily for other atoms, or atomic groups, and are often used as a means of introducing the carboxyl group into compounds. 36 Ct GROUP.—METHANE COMPOUNDS, Sulpho-Substitution-Products of Methane. There are sulpho-derivatives containing sulphur in place of the oxygen, which correspond to most of the oxygen derivatives of methane. Methyl sulphydrate, or methyl mereaptan,CB.S^, corresponding to the methyl alcohol, CH3OH, is a colorless liquid with a most unpleasant odor, boiling at 21". The mercaptans give with mercuric oxide a white crystal- line compound, from which their name* is derived. They are produced by the action of potassium, or sodium sulphydrate, on the alkylogens. Methyl sulphide, (CH3)2S, corresponding to methyl ether, is a liquid with an unpleasant odor, boiling at 41°. Its production is analogous to that of the sulphydrates, but instead of the sulphydrate the sulphide is used. Methyl sulphaldehyde, CH2S, corresponding to methyl aldehyde. It polymerizes to three molecules, so (hat its proper formula is CaH«S.i. It is obtained by the reduction of carbon disulphide. Carbon Disulphide, CS2, corresponding to carbonic acid, C02. It is formed when sulphur vapors are led over glowing coals. A colorless liquid, very refractive, with an unpleasant odor and a sharp taste, boiling at 4G'J. Its sp. gr. is 1.27. It is easily inflammable, burning with a blue flame to carbonic and sulphurous anhydrides : CS2 + 3 02 =C02 +2S02. It is insoluble in water, and miscible with alcohol, ether, fatty and essential oils. It dissolves bromine, iodine, sulphur, phosphorus, fats, etc. In the arts is considerably used as a solvent (extraction of oils, fats, and sulphur). It is also used in medicine. Nascent hydrogen converts it into methyl sulphaldehyde : CS2 +2H2 = CH2S + H2S. Between carbon disulphide and carbonic acid there stands a * " Corpus Mercurio Aptiim." CARBON OXYSULPHIDE. 37 compound, COS, Carbon Oxysulphide. It is a colorless gas, and is produced by the action of very concentrated acids (sulphuric, acetic), on potassium sulphocyanide. It is easily inflammable and is converted gradually by water, quickly by bases, into carbonic acid and hydric sulphide : COS + H20 = C02 +H2S. Corresponding to the numerous salts (carbonates) and derivatives of carbonic acid, there are salts and derivatives of carbon disulphide. Carbonic acid in the free state appears always in the form of an anhydride, but considered in relation to its derivatives it has the formula CO(OH)2. In the same manner, the carbon disulphide must be considered as an anhydride when in the free state. There are deduced from the latter two series of compounds, depending on whether the primary type is CS Primary methyl sulphite, or methyl sulphurous acid, and is an ester, or compound ether, because the methyl is bound to the sulphur by means of oxygen. The other is SO,/^, methylsulphonic acid. In the latter, the hydroxyl group of sulphuric acid is re- placed by a hydrocarbon rest. They are produced by digesting the chlorides, bromides, or iodides of the hydrocarbons with neutral ammonium sul- phite : CH3I + (NH4)2S03 = CH3S03NH4 + NHJ, or by oxidizing the mercaptans with nitric acid, CH3SH + 03 = CH3S03H. Methylsulphonic acid, CH3S03H, and Methylene-sulphonic acid, CH2(S03H)2, are known in the pure state only in the form of their salts. By the oxidation of methyl sulphide, Methylsulphone, (CH3)2S02, is obtained. It has the constitution, OWCH3 o/\CH3 40 Cj GROUP.—METHANE COMPOUNDS. We shall examine the sulpho-acids more thoroughly when we come to the aromatic compounds, for their sulphonic acids are of much greater importance. Nitrogen Substitution Products of Methane. Next to the oxygen derivatives of the hydrocarbons, the nitrogen derivatives are the most important, even surpassing them in variety. Nitrogen as a tri-valent element can substi- tute three hydrogen atoms in one or more hydrocarbons ; in combination with H (as NH=), it can substitute two atoms of H in one or more hydrocarbons ; and, finally, in combination with two H's (NH2~), it can substitute one H atom in a hydrocarbon. It is evident that in these substituted hydrocarbons other substitutions may exist, hydroxyl in place of hydrogen, for instance ; as examples we have : 1) Substitution of 1 N for 3 H's in a hydrocarbon : a) CH=N; b) C(OH)=N ; 2) Substitution of NH for two H's : a) CH2=NH; b) CO=NH ; 3) Substitution of NH2 for II: a) CH3"NH2 ; b) CHO"NH2. This class of compounds is more easily understood when we look at them from another point of view, that is, as derived from ammonia. In ammonia the three H's can be successively substituted : 1) By mono-valent hydrocarbon rests (alkyl rests) : /H yCH3 /CH3 /CH3 NfH NfH NfCH3 NfCH \h \h \h \ch Ammonia Methylamine Dimethylamine Triniethylamine AMINES.—AMIDES. 41 These bodies are called amines, or amine bases. They re- semble ammonia in every way, possess basic properties, unite directly with acids, as, for instance, NH3HC1, ammonium chloride ; NH2(CH3)HC1, methylammonium chloride; NH(CH3)2HC1, dimethylammonium chloride ; N(CH3)3HC1, trimethylammonium chloride. It is even possible in these compounds to substitute the H of the acid by an alkyl rest, thus obtaining compounds such as N"(CH3)4C1, tetramethylammonium chloride. In this last compound the chlorine, or halogen, atom can be replaced by hydroxyl, forming the compound N(CH3)4OH, tetramethyl- ammonium hydroxide. Ammonia dissolved in water has also the formula NH4(OH), ammonium hydroxide, but such a compound cannot be isolated, because it falls at once into water and ammonia, NH4(OH) = NH3 + H20. If, however, the four H's of the ammonium hydroxide be substituted by alkyl rests (methyl), the compound becomes stable and can be isolated. 2) The hydrogen of the ammonia can be successively sub- stituted by mono-valent acid rests. The hydroxyl of formic acid, HCO(OH), can, for instance, be replaced by NH2: /H /CHO /CHO /CHO N^-H a) N^H b) N^CHO c) N^CHO \E \h \h \cho Ammonia Formamide Diformamide Triformamide These compounds are called amides. The last two have not yet been produced in the case of formic acid, but we shall meet them under acetic acid. The first amide still possesses weak basic properties ; for by the entrance of the acid rest the attraction of the ammonia for acids is almost neutralized. Amines are, then, substituted ammonias, in which the hydrogen is replaced by hydrocarbon rests, or, when we imagine the hydroxyl to be replaced by the amido-group, by alcohol rests. Amides are substituted ammonias in which the hydrogen is replaced by acid rests. 42 C, GROUP.—METHANE COMPOUNDS. CH3(OH) CH:,(NH2) Methyl alcohol Methylamine HCO(OH) HCO(NH2). Formic acid Formamide The group NH2 is known as amidogen, or the amido-group; NH, as imidogen, or the imido-group. If the organic rest combined with NH2 contains another carboxyl group, as is the case when in dicarboxylic acids only one of the carboxyl groups exchanges its hydroxyl for NH2, compounds arise which have a weak acid character; for the introduction of the NH2 has not the power to entirely overcome the acid properties. Such compounds are called amido-acids •7 T xi , CO(OH) or amic acids. In the compound i , oxalic acid, for CO(OH) instance, one or both of the hydroxyls may be substi- tuted by the NH2 group. In the first case an amido-acid CO-NH2 . . , ., CO-NH2 _ i is formed ; in the second, an amide i . In CO"OH CO"NH2 NH (suc- CHrCOOH CH2"CO/ cinimide), is derived. The imides may be considered as deduced from the amides by the subtraction of NH3: CO/IJ52 = CO=NH + NH3 v^112 Carbimide Carbamide CH2-CO"NH2 CH,-CO\ i = i >NH + NH3. CH2-CO"NH2 CH2~CO/ Succinamide Succinimide From the amic acids they are derived by the elimination of water : C0/JJ22=C0=NH+H20 \utl Carbimide Carbamic acid « CH2-CO"NH2 CH2"CO\ „ i = i >NH + H20. CH2_CO-OH CH2-CO/ Succinamic acid Succinimide 4) All three hydrogen atoms of the ammonia can be replaced by one tri-valent hydrocarbon rest: N^CH N=C(OH). Prussic acid Isocyanic acid (Formonitrile) (Carbouitrile) Compounds of this class are called nitrites. Besides the nitrogen derivatives of the carbon compounds in which the nitrogen is in direct union with the carbon, there are the esters of nitric and nitrous acids with alcohol rests. These have already been noticed. The nitrogen in them is bound to the carbon through oxygen. There is, however, a class of compounds derived from nitric acid, in which the nitrogen is bound directly to the carbon. The hydroxyl of nitric acid can be replaced by a hydrocar- bon rest in a manner analogous to the formation of sulphonic acids from sulphuric acid, (HO)N02, CH3~N02. 44 C, GROUP.—METHANE COMPOUNDS. Such compounds are called nitro-compounds. Their isom- erism with the nitrous esters is evident from the following formulas: CH3"0"NO, CH3N02, Nitrous-methyl ester, derived from HO. NO. CH3"N02, CH3N02, Nitromethane, derived from HO. N02. It is a characteristic property of all nitro-compounds that they are converted into amido-compounds by the action of reducing agents (nascent hydrogen): CH3"N02 + 3 H2 = CH3"NH3 -f- 2 H20, Nitromethane Methylamine while the isomeric nitrous esters are reduced to ammonia and alcohol : CH3_0"NO + 3 H2 = CH3OH + NH3 + H20. The nitro-compounds will be considered more at length under the aro- matic series. Amine s. a) Primary amines, those in which one H of the ammonia is substituted by a hydrocarbon rest. b) Secondary amines, those in which two H's of the ammonia are substituted by hydrocarbon rests. c) Tertiary amines, those in which all three of the H's of the ammonia are substituted by hydrocarbon rests. The primary amine bases resemble ammonia in every respect. They possess nearly the same odor, are strong bases, and their chlorhydric acid salts give with platinic chloride double salts difficultly soluble in water, viz., (CH3NH2 . HCl)2PtCl4. The secondary amine bases are very closely related to ammonia, and are also strong bases. They are less volatile than the primary amines, and their platinum chloride double salts are not so difficultly soluble. AMINES. 45 The tertiary amine bases diverge still more in their chemi- cal properties from ammonia. Their platinic chloride double salts are easily soluble, and their boiling points lie higher than those of the secondary amines. All three classes of amines, however, unite, like ammonia, directly with acids, viz., HCl, HBr, HI, HN03, H2S04. NH3 . HCl; CH3(NH2) . HBr ; (CH?)2NH . HI; Methylammonium bromide Dimethylammonium iodide (CH3)3N . HN03 ; CH3(NH2) . H2S04 ; Triniethylammonium Acid Methylammonium nitrate sulphate [(CH3)2NH]2 . H2S04. Neutral Dimethyl ammonium sulphate The amine is set free from these salts by an alkaline hydroxide : CH3(NH2). HBr + KHO = CH3NH2 + KBr + H20 (CH3)2NH.HI + KHO=(CH3)2NH + KI + H20 (CH3)3N . HN03 + KHO = (CH3)3N +KN03 + H20. If, however, the fourth replaceable hydrogen atom in an ammonium salt is substituted by a hydrocarbon rest, the sub- stituted ammonium compound is obtained, viz., (CH3)4NBr, tetramethylammonium bromide. Alkalis do not set the bases free from these salts. By treatment with silver oxide, however, a base, (CH3)4NOH, tetramethylammonium hy- droxide, is formed. This compound does not show the proper- ties of ammonia, but resembles potassium hydroxide completely in its behavior. It possesses basic properties of a marked character, and forms salts by substitution. We shall now pass to the individual description of the amines. Methylamine, CH3"NH2, or CH5N, is a gas which at a few degrees below zero condenses to a liquid. It has a strong ammoniacal odor, blues litmus paper, is very soluble in water, forms white clouds with chlorhydric acid gas, combines with acids to form crystallizable salts, and yields a difficultly soluble 46 Cj GROUP.—METHANE COMPOUNDS. platinum salt (CH5N . HCl)2PtCl4. It is inflammable and burns with a yellow flame. Dimethylamine, (CH3)2NH, or C2H,N, is a colorless liquid with the odor of ammonia. It boils at 8°. Trimethylamine, (CH3)3N, orC3H9N, is a liquid boiling at 9°. It forms salts with acids. In nature, it occurs in many plants, as the common pigweed, the flowers of the pear-tree, hawthorne, etc., and in the decomposition products of many animal and vegetable substances, viz., pickled herrings and yeast. The salts of these amine bases are almost all soluble in water and alcohol. The behavior of the nitrous salts of the amines is worthy of attention. It is well known that ammonium nitrite, by merely boiling its water solu- tion, is decomposed into nitrogen and water : NH4"N02 = N, + 2H20. The nitrites of the primary amine bases behave in an analogous man- ner, their aqueous solutions being also decomposed on boiling. Instead of the formation of two molecules of water, however, one molecule of water and one molecule of alcohol are produced: N(CH3)Ha~N02 = N2 + CH3OH + H20. In order to produce such a decomposition, it is only necessary to boil the solution of a salt of the amine with a solution of potassium nitrite. The secondary amine bases behave differently. If an aqueous solution of any of their salts is boiled with a potassium nitrite solution, a peculiar compound, the nitroso-derivative of the base is formed : N(CH3)2H2 ~N02 = H20 + N(CH3)2NO. Methylnitroso-amine /CH3 The constitution of this compound is N^CHa \N=0. The nitrites of the tertiary amines are decomposed with difficulty and yield finally the same nitroso-compounds as the secondary amines. The nitroso-amines yield on reduction with zinc dust and acetic acid the hydrazine compounds, viz., (CH3)2N*NO + 2 H2 = H20 -+- (CH3),N"NH2, dimethyl-hydrazine. AMINES. 47 Tetramethylammonium iodide, (CH3)4NI, forms white crys- tals very difficultly soluble in alcohol. By digestion with moist silver oxide, the compound Tetramethylammonium hydroxide, (CH3)4N"OH, is ob- tained. White deliquescent crystals, with strongly basic properties, forming finely crystallizable salts. Formation of the Amines. The primary amines are formed : 1) By boiling the cyanic ethers with an alkali hydroxide : CON"CH3 + 2 KHO = K2C03 + CH3"NH2. Methyl cyanic Methylamine ether 2) By reducing the nitro-compounds with nascent hydrogen : CH3-N/02 + 6 H = CH3"NH2 + 2 H20. 3) By reducing the cyan-compounds with nascent hydrogen : HCN + 4H = H3C"NH2. Cyauhydric acid 4) (In the form of the halogen salts.) By the action of alcoholic am- monia on the chlorides, bromides, and iodides of the hydrocarbons : CHJ + NH3 = CH3(NH2)HI. The secondary amines are formed by the action of the iodides (chlo- rides or bromides) of the hydrocarbons on the primary amines : CHJ + CH3" NH2 = (CH3)2NH . HI. The tertiary amines are formed by the action of the iodides, etc., on the secondary amines : CHJ + (CH3)2NH = (CH3)3N"-f-HI. The substituted ammonium bases are formed by the further action of the iodides, etc., on the tertiary amines : CHJ + (CH;;)3N = (CII3)*NI. It is hence possible to build up in this manner the completely substi- tuted amines from the primary amines. 48 Cj GROUP.—METHANE COMPOUNDS. By the action of ammonia on the iodides, etc., of the hydrocarbons, not only the primary amines are formed, but also both the others, as well as the substituted ammoniums. The reason of this is that all the different reactions take place at the same time. Amides and Amic Acids. When the hydroxyl group of a monobasic acid is replaced by the amido-group NH2, an amide is formed. Formic acid, HCOOH, gives formamide, HCO(NH2). It is produced by heating formic ester with gaseous ammonia : CHOOC2H5 + NH3 = CHO(NH2) + C2H5OH. Ethyl formic ester Formamide Alcohol Colorless liquid, easily soluble in water. Boils at 194°. Acids and bases convert it into formic acid and ammonia : CHO(NH2) + H20 = CHOOH + NH3. On distillation with anhydrous phosphoric acid, water is split off and the nitrile is produced : CHO(NH2) = CHN + H20. ccKnh(2°2H5) Ethylurea. ^N^Sh5?) ethylurea, COetc- Substituted ureas may be produced : 1) By heating urea with amine bases, aei-chlorides, and acid anhy- drides : 2) By boiling potassium cyanate with the sulphates of the amine bases : 3) By the action of carbon oxy-chloride on the amine bases. The following compounds are also derived from urea : Allophanicacid, CO<^ -kttt = C2H4N203, Biuret, . . . CO<^™^CO"NH2 = C2H5N303 (v. s.). The esters of allophanic acid are formed when cyanic acid gas is led into an alcohol : 2 CONH + CH,0 = C3H6N203 = CO^Jga-COOCH Sulphocarbamic acid, sulphocarbaminic acid, corresponding to carbamic acid, CO(SH)(NH2). The free acid is very 52 Ct GROUP.—METHANE COMPOUNDS. unstable. Its ammonium salt is obtained by the action of carbon disulphide on alcoholic ammonia. Sulphocarbamide, thiurea, ^S^^tt3, corresponding to urea, CO<^ tsttt2* is obtained from ammonium sulphocyanate. Its formation is entirely analogous to that of urea from ammonium cyanate: CON(NH4) = CO(NH2)a Am. cyan. Urea CSN(NH4) = CS(NH2)2. Am. sulphocyan. Sulpho-urea Dry ammonium sulphocyanate is heated for some time at 140°. Only a part of it, however, is converted into thiurea. Sulphocarbamide crystal- lizes in long, colorless needles or prisms, fusing at 140\ It combines with acids like urea. The representative of the following group can be derived from urea by the replacement of the oxygen by the di-valent ammonia rest, the imido-group, just as thiurea is derived from urea by the replacement of the oxygen by sulphur. coS02 gives Sulphuric acid CH3"N02 and CH3"0~N02 Nitromethane Metliylnitric ester CH3 HO S09 and CH30 HO soc Methylsulphonic acid CH. CH^ Methylsulphone °-\S09 and Metliylsulpburic acid CH30\so ch'o/^0* Methylsulphuric ester HO Ct GROUP.—METHANE COMPOUNDS. HO\ HO-^PO HO/ Phosphoric acid gives rcH3X HO^PO HO/ Methylphosphinic acid CHa\ CH3Os and HO^PO HO/ Methylphosphoric acid CH,0\ CH3-)PO and CH3O^PO HO/ HO/ Dimethy Iphosphoric acid Dimethylphosphinic acid CH3\ CH30\ CH3^PO and CH30-^PO CH3/ CH30/ Trimethylphos- Trimethylphosphoric phinic oxyd ester In the same manner, a hydroxyl of silicic acid can be replaced bj alkyl rests : g^SiO yields gJ^SiO. Silicic acid This compound, CH3SiOOH, on account of the tetra-valence of the silicon, has been considered as acetic acid in which the carbon of the carboxyl group has been replaced by a silicon atom, and it has hence been called silico-acetic acid. Arsenic Derivatives. The methyl- and dimethy 1-arsine derivatives of the tri- and penta-valent arsenic are not yet known. Analogous compounds have been produced, however, in which the hydrogen of the hydrogen arsenide is replaced by chlorine. Monomethyl-arsenic dichloride, CH3AsCl2, liquid boiling at 133\ With chlorine it unites to monomethyl-arsenic tetrachloride, CH3AsCl,. Dimethyl-arsenic chloride, (CH3)2AsCl, liquid boiling at about 100 \ By the action of chlorine it forms dimethyl-arsenic trichloride. (CH3)2AsCl3. Trimethyl-arsine, (CHs)3As. Colorless liquid with an offensive odor, boiling at 120°. It unites with chlorine, bromine, iodine, oxygen, sulphur, etc., in the same manner of trimethylphosphine. Tetramethyl-arsonium iodide, (CH3)4AsI. ANTIMONY DERIVATIVES. 71 Tetramethyl-arsonium hydroxide, (CH3)4AsOH. The most important arsenic compound of methyl is P FT \ /PIT Arsenic dimethyl, cacodyl, qlt3 \A.s-As<^QrT3, or (CH3)4As2. It is produced by the distillation of equal parts of dry potassium acetate and arsenous anhydride. It is a liquid with an extremely disagreeable odor, boiling at 170°. When exposed to the air it fumes and ignites. By the slow action of oxygen, cacodyl oxide and cacodylic acid are formed. Cacodylic oxide, alcarsine, p,,3\As-0~As^/-,TT3, is the chief pro- duct of the above distillation of potassium acetate and arsenous anhydride. It is an oil with an offensive odor, boiling at 150°. Exposed to the air it does not fume, but oxidizes slowly to Cacodylic acid, dimethyl-arsinic acid, qH3 \AsO(OH). Large, odor- less, deliquescent prisms, fusing at 200°. Its salts are crystalline. It cor- responds to the dimethylphosphinic acid. Methylarsinic acid, CH3AsO(OH)2, corresponding to methylphosphinic acid, is also known, and is produced by the action of silver oxide on methyl arsenic dichloride, CH3AsCl2. All of these arsenic derivatives are made from cacodyl. Antimony Derivatives. The compounds of methyl with tri- and penta-valent anti- mony possess still less basic character than the preceding derivatives. Trimethylstibine, (CH3)3Sb, obtained by the action of potassium anti- monidc on methyl iodide : K3Sb + 3 CH3I ■- 3 KI + (CH3)3Sb. Colorless liquid boiling at 86°. With methyl iodide it unites to Tetramethyl-stibonium iodide, (CH3)4SbI, a hard crystalline mass which yields with moist silver oxide. Tetramethyl-stibonium hydroxide, (CH3)4Sb"OH, white, deliquescent crystalline mass with strong basic properties. Trimethylstibine iodide, (CH3)3SbI2. Obtained by digestion of metallic antimony with methyl iodide. It crystallizes in needles or prisms. In a similar manner trimethyl bismuthine, (CH,)3Bi, is obtained by the action of methyl iodide on potassium bismuthide. The methyl com- 72 Ct GROUP.—METHANE COMPOUNDS. pound of boron, trimethyl borine, (CH3)3B, is also known. It is a color- less gas, with a sharp, peculiar odor. Compounds of Methyl with Metals. 1) By the digestion of finely granulated zinc with methyl iodide, methyl-zinc iodide, CH3ZnI, a crystalline compound, is obtained, which, by distillation, falls into zinc iodide and zinc methyl: 2 CH3ZnI = (CH3)2Zn + Znl2. Zinc methyl is a colorless liquid boiling at 46°. It has an unpleasant odor. When exposed to the air, it ignites and burns with a greenish-blue flame. Water decomposes it immediately into methane and zinc hydroxide: (CH3)2Zn + 2 H20 = 2 CH4 + Zn(0H)2. 2) By the action of methyl iodide on mercury, a crystalline compound, methyl-mercury iodide, CH3HgI, is obtained, while by the action of methyl iodide on mercury amalgam, mercury methyl, (CH3)2Hg, is formed: 2 CHJ + Na2Hg = (CH3)2Hg-f- 2 Nal. Colorless liquid insoluble in water, boiling at 95°, and easily combusti- ble. Its vapors are very poisonous. 3) Methyl iodide and magnesium filings give magnesium methyl, (CH3)2Mg, a liquid which has a strong odor and ignites on exposure to the air. 4) By the action of zinc methyl on silicium chloride, tetramethyl- silicium, (CH3)4Si, is produced: 2 (CH3)2 Zn + SiCl4 = (CH3)4Si + 2 ZnCl2. Colorless, easily combustible liquid, boiling at 30°. 5) Methyl iodide and an alloy of tin and sodium yield tin tetramethyl, Sn(CH3)4. It is a liquid with an ethereal odor, boiling at 78°. 6) Lead chloride and zinc methyl give lead tetramethyl, Pb(CH3)4. This compound proves the tetra-valence of lead. In conclusion, we will consider briefly some of the organic salts, or esters, of methane. The method of producing methylsulphuric acid and methyl sulphuric ester have already received a passing notice. The methylsulphuric acid is formed by mixing carefully methyl alcohol and sulphuric acid. The excess of sulphuric acid is METHYLSULPHURIC ACID. 73 removed by adding barium carbonate to the mixture diluted with water. Barium sulphate is formed and separates, while the methylsulphuric acid is transformed into the easily soluble barium salt. The barium sulphate is removed by nitration, and the barium methylsulphate obtained by evaporation of the solution. From the latter the methylsulphuric acid is set free by sulphuric acid. In the free state it is but little known. It forms long,deliquescent needles, and its aqueous solution on heating breaks into methyl alcohol and sulphuric acid : CH,0\o^ . tt ^ HOx >/ Ho >S02 + H20 = JJg >S02 + CH3(OH). It is a monobasic acid, and forms with metals finely crystal- lizing salts, which are easily soluble. Its potassium and barium salts are frequently used instead of methyl iodide, bromide, or chloride for the production of other derivatives of methane, since the rest S04H is easily substituted. By distil- lation of potassium methylsulphate with potassium cyanide, for instance, methyl cyanide and potassium sulphate are formed : CIko)>so2 + KCN = CH3CN + KO^03 orK*S°4- CH 0\ Methyl Sulphuric Ester, nn'o/^s' ^s f°rme{^ Dy the distillation of a mixture of 1 part of methyl alcohol with 8 parts of sulphuric acid. It is a colorless liquid boiling at 188°, and has the odor of garlic. Methyl Nitric Ester, CH3ON02, is formed by the distilla- tion of nitre and methyl alcohol with sulphuric acid. It is a liquid with an ethereal odor, boiling at 66°, which at a higher temperature (150°) explodes violently. CH,0\ Methylboric ester, CH30—^Bo, is formed by the action of boron tri- CH30/ chloride on methyl alcohol: 74 Cj GROUP.—METHANE COMPOUNDS. BoCl3 + 3CHaOH = (CH30)3Bo + 3 HCl. Colorless liquid boiling at 72°. With water it breaks into boracic acid and methyl alcohol: (CH30)3Bo + 3H20 = 3 CH3OH + Bo^OH)3. Methyl silicic ester, (CH30)4Si, is produced from silicon chloride and methyl alcohol : 4CH3OH + SiCl4 = (CH30)4Si + 4 HCl. Colorless liquid with an ethereal odor, b. p. 124°. With water it decomposes after some time into silicic acid and methyl alcohol. The three esters of phosphoric acid with methyl have already been men- tioned : CH30\ CH30\ CH30\ HO-^PO, CH30-^PO, and CH3O^PO. HO/ HO/ CH.O/ Methylphosphoric Dimethylphosphoric Methylphosphoric acid acid ester The compounds which have thus far been considered contain only one atom of carbon, or contain several atoms of carbon which are not directly connected, as, for instance, methyl ether, H3C~N~CH3 ^ , , H3C 0"CH3, and tnmethylamme, ■ '. Only two CH3 compounds have been mentioned in which carbon is united to CN" carbon. These were cyan, i , and cyanmethane, or aceto- CH nitrile, i 3. These were considered in this group in order ' CN not to lose sight of their relation". We come now to the great classes of compounds which contain several atoms of carbon directly united. We can imagine a hydrogen atom of methane to be replaced by the methyl group, thus forming the compound, CH3~CH3, dimethyl, from which derivatives may be produced in the same manner as the methyl compounds from methane. C2 GROUP. Ethane Compounds. Hydrocarbons. 1) The two carbon atoms are united by a simple binding. Ethane, Dimethyl, CH3~CH3, C2H6, is formed by the action of water on zinc-ethyl: (C2H5)2Zn + 2H20 = 2 C2H6 + Zn(OH)2. Or by the electrolysis of acetic acid : 2 CH3"COOH = C2H6 + 2 C02 + H2. It is a colorless gas, burning with a faintly luminous flame. By the action of chlorine the hydrogens are substituted by it: CH3"CH3 + Cl2 = CH3-CH2C1 + HCl. Ethyl chloride 2) The two carbon atoms are united by a double binding. Ethylene, Olefiant Gas, CH2~CH2, C2H4. It is produced by heating 1 part of alcohol with 6 parts of concentrated sulphuric acid. The elements of a molecule of water are extracted from the alcohol, (predisposing affinity). CH3-CH2OH = CH2=CH2 + H20. It is a colorless, poisonous gas, with an unpleasant, suffocat- '75 76 C„ GROUP.—ETHANE COMPOUNDS. ing odor, burning with a luminous flame. It combines directly with chlorine, bromine, and iodine : CH2=CH2 + Cl2 =CH2CrCH2Cl. In the presence of platinum black it unites with hydrogen to ethane : CH2=CH2 + H2 = CH3_CH3. With oxygen it forms a compound, ethylene oxide, H2C~CH2, which is 0 isomeric with aldehyde, CH3 CHO. 3) The two carbon atoms are united by a triple binding. Acetylene, CH=CH, C2H2. It is formed directly from its elements, when electric sparks are passed between carbon poles in an atmosphere of hydrogen. It is also pro- duced when organic bodies are exposed to a high heat, e.g., when methane, alcohol, ether, etc., are passed through heated tubes, or when organic substances (ether, benzene,) are burnt with an insufficient supply of oxygen. It is present in small amounts in illuminating gas. It is made by boiling ethylene bromide with alcoholic potash : CvH.Br* + 2 KOH = C2H2 + 2KBr + 2H20. Or by passing ethylene chloride over heated lime. Acetylene is a colorless gas with a strongly offensive odor, burning with a luminous smoky flame. With nascent hydro- gen it unites to ethylene. It combines directly with the halo- gens, forming C2H2C12 and C2H2C14, etc. A characteristic property of this compound is its absorption by an ammoniacal solution of cuprous chloride, Cu2Cl2, or silver nitrate solu- tion, AgN03. In the former case a red precipitate, C2C'u.. -f- H20, is formed, while in the latter a brown substance, C2Ag2 + H20, is precipi- tated Both of these compounds explode by heating or percussion. By leading acetylene over melted potassium, hydrogen is evolved, and the compounds C2HK and C2K2 are formed. In the presence of platinum- black, acetylene unites with hydrogen to ethane. ETHYLIDINE CHLORIDE. 77 Halogen Substitutions of Ethane. Ethyl Chloride, Monochlorethane, CH3"CH2C1, or C2H5C1, is formed by the action of chlorine on ethane. It is made by the action of gaseous chlorhydric acid on ethyl alcohol. It is a colorless liquid with a pleasant odor, boiling at 12°. Chlo- rine acts on it, forming higher substitution products. As has already been explained in the Introduction (p. 10), the higher substituted halogen derivatives of ethane, owing to the distribution of the chlorine atoms, form two isomeric series. Ethyl Bromide, Monobromethane, CH3"CH2Br, or C2H5Br. It is produced by digesting ethyl alcohol with gaseous bromhydric acid, or by dropping bromine into alcohol containing melted phosphorus. It is a colorless liquid with a pleasant odor, boiling at 39°. Ethyl Iodide, Mono-iodo-ethane, CH3"CH2I, or C2H5I. To 1 part of amorphous phosphorus in 5 parts of alcohol, 10 parts of iodine are carefully added, the whole allowed to stand 24 hours and then distilled. It is a colorless liquid boiling at 72°. On exposure to the light it gradually turns brown. Ethylene Chloride, Ethene Chloride, Dichlorethane, Dutch Liquid, CH2CrCH2Cl. This substance is formed by expos- ing a mixture of chlorine and ethylene to sunlight. It is made by passing equal parts of chlorine and ethylene into boiling antimony pentachloride. It is a liquid with an odor resem- bling chloroform. It boils at 85°. With alcoholic potash it splits off HCl : CH2C1-CH2C1 + KHO = CH2=CHC1 + KC1 + H20. Isomeric with it is Ethylidene Chloride, Ethidene Chloride, Chlorethylidene, Chlo- rethidene, CH3-CHC12, or C2H4C12. It is obtained as the 78 C2 GROUP.—ETHANE COMPOUNDS. first product of the action of chlorine on ethyl chloride. Col- orless liquid with a pleasant odor, boiling at 57.5°. Mono-chlor-ethylene chloride, CH2C1=CHC12. Liquid boiling at 115°. With alcoholic potash, an HCl splits out: CH2C1=CHC12 + KOH = CHC1=CHC1 + KC1 + H20. Mono-chlor-ethylidene chloride, methyl chloroform, CH3~CC13, or C2HSC13. Boils at 75°. Alcoholic potash converts it into the acetate : CH3-CC13 + 4 KOH = CH3_COOK + 3 KC1 + 2 H20. Dichlorethylene chloride, dichlorethene chloride, CH2C12~CHC12, boils at 147°, and by the action of KOH is converted into Dichlorethylidene chloride, dichlorethidene chloride, CH2C1~CC13, or C2H2C14. Boils at 127.5°. By the action of alcoholic KOH, CHCrCCl2 is also formed. Pentachlorethane, CC13~CHC12. Boils at 158°. Perchlorethane, hexachlorethane, C2C16, is the final product of the action of chlorine on ethyl chloride. It crystallizes in well-formed rhombic crystals, which fuse at 185°, but boil at 184°, so that under the ordinary atmospheric pressure it sublimes without melting. By the action of weak reducing agents, as potassium sulphydrate, it falls into C2Cli and Cl2. We see from the foregoing that alcoholic potash converts the higher chlo- rine derivatives of ethane into chlorinated ethylenes with elimination of HCl. The following is a list of the chlorine derivatives of ethane : Ethyl chloride....... CHS0« + OH„COONa - CH.COOC.H, +1j|(£>S01 Ethylsulphuric acid ESTERS. 91 It is, however, not usually necessary to produce the acid sulphuric ester in the pure state. The alcohol is mixed with the sulphuric acid and the salt of the organic acid, and the whole distilled. The esters can also be produced by saturat- ing a mixture of the alcohol and the organic acid with chlor- hydric acid gas. In this case the chlorhydric acid acts most probably as a dehydrating agent: C2H402 + C2H60 = C2H302 ~ C2HS + H20. Acetic acid Alcohol Acetic ester The esters are decomposed into the alcohol and a salt of the acid by boiling with an alkali : CH3_COO " C2HS -f NaOH = CHH_COONa -f- C2HnOH. Acetic ester Sodium acetate Alcohol The ease with which a halogen substitution of a hydrocarbon and a salt of an organic acid yield the ester, and the facility with which the ester thus formed yields the alcohol by boiling with an alkali, affords us a most excellent method for producing alcohols from chlorides, bromides, etc. CH3-CH2Cl + CH3_COONa = CH3_COO~ CH2-CH3 + NaCl Ethyl chloride Sodium acetate Acetic ethyl ester CH3_COO-CH2-CH3 + KOH = CH3"COOK + CH3"CH2OH. Acetic ethyl ester Potassium acetate Alcohol With ammonia, the esters yield acid amides and alcohol : CH3_COOC2H5 + NH3 = CH3"CONH2 + C2H5OH. Metallic sodium acts on acetic ester substitutingly, liber- ating hydrogen and forming, besides sodium ethoxide, the sodium compound of a complicated compound ether, aceto- acetic ester : 2 CH3-COOC2H5 + Na2 = H2 + C2H5ONa + CH3-CO"CHNa-COOC8H5. In this compound, the sodium atom can be replaced by both alcohol and acid rests. 92 C2 GROUP.—ETHANE COMPOUNDS. The sodium aceto-acetic ester is easily decomposed by acids, yielding the aceto-acetic ester, CcHi0O3 = CH3~CO~CH2-COOC2Hr„ a colorless liquid boiling at 181°, which by the action of sodium is converted back into the sodium aceto-acetic ester. As the sodium atom can be replaced by means of the chlorides, bromides, and iodides of both alcohol and acid rests, and the compounds thus formed can be decomposed in a character- istic manner by potash, the aceto-acetic ester is used as the starting-out point for the production of a great number of compounds. By the action of ethyl iodide on sodium aceto-acetic ester, ethyl-aceto- acetic ester is formed, C8H1403 = CH3"CO"CH(C2H5)"C02C2H5, which by the action of sodium yields, with evolution of hydrogen, sodium ethyl- aceto-acetic ester. This by treatment with ethyl iodide yields diethyl- aceto-acetic ester, Ci0H18O3 = CH3~CO-C(C2H5)a~C02C2H5. Acetyl chloride and other aci-chloride's give with sodium aceto-acetic ester the corresponding aci-compounds, viz., CH3~CO~CH(C2H30)~C02C2H5. The decomposition of aceto-acetic ester and its derivatives takes place in two ways. (1) Out of each molecule, two acids are formed, one of which is always acetic acid : 1) CH3-CO-CH2-C02C2H5 + 2 H20 = CH3"C02H Aceto-acetic-ester Acetic acid + CH3-C02H + C2H60. Acetic acid 2) CH3-CO-CH(C2H5)-C02C2H5 + 2 H20= CH3"C02H Ethylaceto-acetic ester Acetic acid -f CH2(C2H5)-C02H + C2H60. Butyric acid 3) CH3-CO-C(C2H5)2-C02C2H5 -f 2 H20 = CH3"C02H Di-ethyl-aceto-acetic ester Acetic acid + CH(C2H5)2"C02H + C2H60. Di-ethylacetic acid (2) Carbonic acid and a ketone are formed : 1) CH3-CO-CH2-C02C2H5 + H20 = CH3-CO_CH3 Aceto-acetic ester Acetone + C02 -f C2H60. 2) CH3-CO-CH(C2H5)-C02C2H5+H20 = CH3-CO-CH2(C2H5) Ethylaceto-acetic ester Methylpropylketone + C02 + C2H60. 3) CH3-CO-C(C2H5)2-C02C2H5 + H20 = CH3-CO-CH(C2H5)a Diethylaceto-acetic ester Methylamylketone + C02 -f C2H60. ACETAMIDE. 93 In both cases the ester is saponified with the formation of alcohol. The esters homologous with acetic ester behave in the same manner. Acetic acid when treated with phosphorus trichloride ex- changes its OH for CI, forming Acetyl Chloride, CH3_CO"Cl, or C2H30C1 : 3 CH3"COOH + PC13 = 3 CH3"COCl + PH303. It is a colorless very mobile liquid with a penetrating odor. It boils at 55°, and fumes slightly in the air. Acetyl chloride is our first example of an aci-chloride. Aci- chlorides exchange their chlorine very easily for other elements or atomic groups. They are all decomposed by water with regeneration of the acid : CH2COCl + HHO = CH3COOH + HCl. Even the moisture of the air decomposes them gradually. With an alcohol, the ester is formed : CH3~COCl + CH3OH = CH3"CO"OCH3 + HCl. Methyl acetic ester With ammonia, the amide : CH3COCl + 2 NH3 = CH3"CONH2 + NH4C1. With salts of the organic acids, the anhydride : CH3"COCl + CH3"COONa = CH3~CO"0"CO"CH3 + NaCl. Acetic anhydride In a similar manner the acetyl bromide and acetyl iodide have been produced. Both are liquids, the former boiling at 81 % the latter at 108°. By action of silver cyanide, CH3~CO"CN, on acetyl chloride, acetyl cyanide is formed. It is a liquid boiling at 93°, and by the action of chlorhydric acid is converted into pyroracemic acid. Acetamide, CH3"CO"NH2, is obtained by the action of ammonia on acetic ester, and by the distillation of ammonium acetate : CH3"COO(NH4) = CH3"CO(NH2) + H20. 94 C2 GROUP.—ETHANE COMPOUNDS. Acetamide is also produced by heating acetic acid with potassium sul- phocyanide for several days. At first, potassium acetate and sulpho- cyanic acid are formed. The latter then acts on the free acetic acid: CH3"COOH + HSCN = CH3"CO " NH2 + COS. Acetamide Carbon oxysulphide Acetamide is a colorless, crystalline substance fusing at 78°, and boiling at 222°. It has a peculiar odor. Phosphoric an- hydride acts dehydratingly on it, forming acetonitrile (methyl cyanide) : CH3"CO"NH2 - H20 = CH3_CK CH3"CO\ By heating acetic acid with acetonitrile, diaeetamide, CH3~CO^N, H/ is formed, which is very similar to acetamide: CH3"CO\ CH3"CN + CH3-COOH = CH3"CO^N. H/ It fuses at 59° and boils at 210°-215°. ' By heating acetic anhydride (see below) with acetonitrile, triacetamide, CH3~CO\ CH3 CO—?N, is formed, which also resembles acetamide. It fuses at 78°. CH3"CO/ CH3-CN + kS3-nn >0 = CH3_CO^N. CH3 CO/ CH3-C0/ When acetyl chloride and sodium acetate are distilled together, there is formed, besides sodium chloride, CH ~C0\ Acetic Anhydride, njr3-rt(\ /O. A colorless liquid with an odor resembling acetic acid. It boils at 138°. It sinks in water, and is gradually decomposed by it into acetic acid : CH^CO/*0 + H2° = 2 CH-fCOOH. Barium peroxide converts acetic anhydride into acetyl superoxide, CH3_CO-0 „__i, or C4H0O4. It is a thick oil, which acts as a strong oxidizing CH3"CO"0 6 & agent, and, when heated, explodes. GLYCOLS. 95 By leading chlorine into acetic acid, the hydrogen of the methyl is replaced by chlorine, and the following compounds are obtained : 1) Monochloracelic acid, CH,Cl~COOH, a crystalline, deliquescent mass. It fuses at 62° and boils at 187°. It forms crystalline salts, and exchanges its chlorine atom for other mono-valent atomic groups. 2) Dichloracetic acid, CHCl2~COOH, is an easily fusible, crystalline substance boiling at 195°. Its ethyl ester, CHCl2~COOC2H5, is formed by the action of potassium cyanide on an alcoholic solution of chloral hydrate. It is a liquid boiling at 156°. 3) Trichloracetic acid, CCl3~COOH, is also obtained by the oxidation of chloral. It is a crystalline, deliquescent substance, boiling at 200". Potassium hydroxide decomposes it into chloroform and potassium carbonate : CClrCOOH + 2 KOH = CC13H + K2C03 + H20. By the action of sulphuric anhydride, acetic acid is converted into acetosulphonic acid, CH2(S03H)~C00H, a crystalline, easily soluble, dibasic acid. As yet we have considered only those oxygen derivatives of ethane in which the hydrogen atoms of the second CH3 remained intact, or, at most, were replaced by chlorine atoms. If, however, the hydrogen atoms of the second CH3 are replaced by hydroxyls, compounds are formed which are alco- hols, aldehydes, or acids, depending on the number of H's replaced by hydroxyl. If one H in each of the CH3-groups is replaced by an OH, the compound, CH2(OH)"CH2(OH), is formed. This naturally possesses alcoholic properties, as it is, in fact, a double alcohol. Similar compounds are also known in the C3, C4, and C5 series. They are called Glycols. The H of the hydroxyl groups can be replaced by hydrocar- CH2"OH . , . , bon rests, ethylene glycol, ' , yielding the mono-ethyl ether and di-ethyl ether : CH2(OC2H5) CH2(OC2H5) CH2(OH) an CH2(OC2H5) 96 C2 GROUP.—ETHANE COMPOUNDS. The mono-acetyl, di-acetyl, and nitric esters are also known : CH2(0"C2H30) CH2(OC2H30) CH2(ONO)2 CH2(OH) CH2(OC2H30)' CH2(ONO)2* Ethylene Glycol, Ethylene Alcohol, CH2(OH)~CH2(OH), or C2H602, contains one more 0 than ethyl alcohol. It is made from ethylene bromide : By digesting ethylene iodide with silver acetate, the di-acetyl glycol ester is obtained: CH2(C2H302) CHJ-CHJ + 2 AgC2H302 = AH H + 2 Agl, which, by boiling with potassium hydroxide, is converted into glycol: CH2(C2H302) KHO CH2(OH) C2H302K CH2(C2H302)+ KHO = CH2(OH) "*" CaH202K Ethylene acetaie Glycol Potassium acetate It is a colorless, odorless, viscous liquid, boiling at 197°. On digestion with chlorhydric acid, it is converted into CH2C1~CH2(0H), glycol-chlorhydrin, which by treatment with potassium hydroxide is decomposed into ethylene oxide: CH "CH2 Y CH2CrCH2OH + KOH = C2H40 + KC1 + H20. Ethylene oxide Polyglycols are formed with glycol. They are constituted as follows : Di-ethylene glycol, C4H10O3 = CH2(OH)-CH2"0"CH2_CH2(OH). Tri-ethylene glycol, C 6 H14 0 4 = CH2(OH)-CH2-0"CH2"CH2-0_CH2-CH2(OH), etc. GLYCOLLIC ACID. 97 These glycols stand in the same relation to glycol as ordinary ether to alcohol. As acetic acid is derived from alcohol, glycollic acid, CH2OH"COOH, is derived from glycol. It is produced by boiling monochloracetic acid with an alkali : CH2CFCOOH+ KOH = CH8(OH)"COOH + KC1. It can also be obtained by oxidizing glycol in the same man- ner that acetic acid is formed from alcohol. We see from the formula of glycollic acid that it must combine the properties of an alcohol and an acid. If the H of the carboxyl group be replaced by the ethyl group, CH2(OH)~COOC2H5 is formed, which is the ester of glycollic acid and analogous to acetic ester. If the H of the hydroxyl, however, is replaced by the same group, CH2(OC2H5)~COOH is obtained, which is a new acid, ethoxyglycollic acid, and which neutral- izes bases with the same power as glycollic acid. If the hydroxyl of glycollic acid be replaced by the amido-group, NH2, a neutral body, CH2(OH)~CONH2, glycol-amide, analogous to acetamide, is formed. The introduction of NH2 in place of the OH of the CH2OH, influences the compound but little, and the compound which is obtained, CH2(NH2)COOH, amido-acetic acid, or glycocoll, is a decided acid. We see hence that there are a great number of isomeric compounds depending on which carbon atom is involved in the substitution. The more important will be mentioned. Glycollic acid is a white, deliquescent, crystalline mass, fus- ing at 80°. It cannot be distilled without decomposition. In water and alcohol it is very soluble. It forms salts, esters, and ester acids. Phosphorus trichloride converts it into gly- collic chloride: 3 CH2(OH)"COOH + 2 PC13 = 3 CH2CrCOCl + 2 PH303, which is identical with monochloracetyl chloride. It is decomposed by water into monochloracetic acid and chlor- hydric acid : CH, crcoci + H20 = CH2CrCOOH + HCl. 7 98 C2 GROUP.—ETHANE COMPOUNDS. Of the other substitutions of glycollic acid we shall mention only glycolamide, CH2(OH)~CO(NH2), which forms color- less crystals easily soluble in water, and slightly in alcohol; and Glycocoll, Amido-acetic acid, Glycine, CH2(NH2)~COOH, which is formed by the decomposition of glue by sulphuric acid, and from many substances existing in the animal organism (bile acids, uric acid, hippuric acid). It is also formed by the action of monobromacetic acid on ammonia : CH2Br"COOH + NH3 = CH2(NH2)"COOH + HBr. Large, colorless, rhombohedral crystals, fusing at 170°. It is stable in the air, easily soluble in water, and insoluble in alcohol. Glycocoll is a weak acid, exchanging the H of its hydroxyl for bases. It also combines with acids, since it is both an amine- base as well as an acid. The copper compound, (C2H4N02)2Cu -I- H20, which is obtained by dissolving copper oxide in a hot solution of glycocoll, is a characteristic example of this class of salts. It crystallizes in deep blue needles. In the same manner that glycol forms poly-glycols, glycollic acid yields %)oly-glycollic acids. Di-glycollic acid, C4H605 = C02H"CH2"0"CH2"C02H, which is formed with glycollic acid, when the latter is made from mono-chloracetic acid, is an example of this class. Glycollic acid forms a peculiar anhydride, glycol lide : c^o., o) CO(NH2)^ It is a white powder almost insoluble in water. When heated with phosphoric anhydride, it yields cyanogen : CO(NH2) 60(NHl) = C'N- + 2H-0- OXALIC ACID. 101 Phosphoric anhydride acts as a dehydrating agent, because it has a strong tendency to pass into phosphoric acid. Cyanogen may be considered as the nitrile of oxalic acid in the same way that cyanhydric acid is the nitrile of formic acid, and methyl cyanide the nitrile of acetic acid. All nitriles are converted into their correspond- ing acids by the addition of the elements of water : HCN + 2 H20 = HC02H -f NH3 Cyanhydric Formic acid acid CHrCN + 2 H20 = CH3"C02H + NH3 Methyl cyanide Acetic acid CN C02H i +4H.O+ i +2NH3. CNT ^ C02H ^ Cyanogen Oxalic acid Since oxalic ethyl ester yields oxamide when treated with ammonia, it gives substituted oxamides when treated with substituted amines. With ethylamine, for example, di-ethyloxamide is produced. Phosphorus pentachloride converts oxamide into a very unstable com- _, CC12~NH2 . . . CC1=NH pound, i , from which HCl is eliminated, forming first i , ^ CC12"NH2 CC1=NH CEN CO"NHCH3 . and then 1 . If dimethyloxamide or diethyloxamide, 1 , is CEN CO-NHCH3 - taken instead of oxamide, the chlorine compound which is formed loses three molecules of HCl, forming the bases chloroxalmethyline, C4H5C1N2, and chloroxalethyline, C6H9C1N2. Sulpho-Siibstitutions of Ethane. The sulpho-substitutions of ethane are not as numerous as the oxygen derivatives, and on account of their lesser impor- tance only a few of the better known will be mentioned. Ethylmercaptan, CH3"CH2"SH, or C2H6S, corresponds to the ethyl alcohol. It is produced by the distillation of potassium ethylsulphate or ethyl chloride with potassium sulphydrate : C2H6(KS04) +KSH = C2H5(SH) + K2S04 C2H6(C1) +KSH = C2H6(SH) + KC1. 102 C2 GROUP.—ETHANE COMPOUNDS. It is a colorless liquid with a highly offensive odor. It boils at 36°, is but slightly soluble in water, and is miscible with alcohol and ether. The H of its SH is easily replaced by metals, forming mercaptides (C2H5SK). Fuming nitric acid oxidizes it into ethylsulphonic acid : C2H5SH + 03 = C2H5"S03H. By distilling potassium ethylsulphate with potassium sul- phide we obtain : Ethyl Sulphide, fixj3-r ?ieids el!:)80*- Dicithylsulphone In these compounds the sulphur is of course hexa-valent as in sul- phuric acid. Ethyl sulphide unites directly with ethyl iodide : (C,H,),S + CBHBI = (CtH6)sSI. C H \ The constitution of this compound is p2TT5 ^>S C2H5- ETHYL SULPHIDE. 103 The atom of iodine can be replaced by any acid rest or by hydroxyl. In the latter case, a strongly basic substance is formed, which attracts carbonic acid from the air. These peculiar compounds, which show sulphur to be a tetra-valent element occur in the other carbon series, and are called sul- phine compounds. This one in particular is tri-ethyl-sulphine iodide. If potassium ethylsulphate is distilled with K2S2, instead of K2S, we obtain : CH3 CH2 S Ethyl Disulphide, _ i ,orC4H10S2, to which there CH3 CH2 o is no corresponding oxygen compound. It is similar to ethyl sulphide in its properties and boils at 151°. Ethyl Sulphaldehyde, CH3~CHS, or C2H4S, corresponds to ethyl aldehyde. It is obtained by leading hydrogen sulphide through aldehyde. An oil is formed which is decomposed by acids, yielding sulphaldehyde, a white, crystalline body. It is properly the triple polymer 3 C2H4S = CGH12S3. The sim- ple aldehyde has not yet been obtained. Thiacetic acid, CH3~COSH, or C2H4SO, corresponding to acetic acid. It is formed by the action of phosphorus pentasulphide on acetic acid, or acetyl chloride on potassium sulphydrate : 5 CH3-COOH + P»S» = 5 CH3-COSH + P205 CH3-COCl + KHS = CHrCOSH + KC1. Colorless liquid with the odor of both acetic acid and hydrogen sul- phide. It boils at 93°, and forms salts and esters. CH -CO\ Thiacetic anhydride, njT3~CO/^' *s 'ormed ^y the action of P2S6 on acetic anhydride. It is a colorless liquid boiling at 121°. By the action of ethyl iodide on sodium or ammonium sulphite, ethyl- sulphonic acid, C2H5~ SOaH, is formed. Its salts are well known. It is identical with the acid obtained ,by the oxidation of ethyl mercaptan. 104 C2 GROUP.—ETHANE COMPOUNDS. Nitrogen Substitutions of Ethane. Ethylamine, C2H5~N"H2, or C2H,N, is made from ethyl iodide and ammonia, or from ethyl cyanic ether and potas- sium hydroxide. It is a colorless liquid with an ammoniacal odor, boiling at 18°. It yields crystalline salts with acids. Di-ethylamine, (C2Hg)2NH, or C4Htl]Sr, is made from ethyl iodide and ammonia. It boils at 57°. Tri-ethylamine, (C2HS)3N, or C6H15N, is made in the same manner. It boils at 96°. Tetra-ethylammonium iodide, (C2H5)4NI, is the final pro- duct of the reaction of ammonia on ethyl iodide. It is a white, crystalline mass. With silver iodide it yields : Tetra-ethylammonium hydroxide, (C3H6)4N~OH, which is a base resembling potassium hydroxide. By the action of ammonia on ethylene chloride, CH2CrCH2Cl, anal- ogous compounds are formed : CH — NH Ethylene-diamine, i , or C2H4(NHa)a. CH2 NH2 Di-ethylene-diamine, £2jj4\(NH)2. C2H4\ Tri-ethylene-diamine, C2H4==N2. C2H4/^ They are liquids of basic character. Glycolchlorhydrin unites with ammonia and amine bases, particularly with the tertiary amines, forming substituted ammonium compounds. CH2"OH The compound with trimethylamine is i _ __,._,., trimethyloxethyl- CH2 N(Cll3)3Cl CH2"OH . ammonium chloride. The hydroxide, i _XT/rrn. . Arr. exists in the bile. CH2 N(Cri3)3^Ii It can be produced by the action of alkalis on a substance occurring in white mustard seeds (sinapin), and is called choline. It is a strongly basic CH2"I body, and gives with iodohydric acid the compound CH_-N(CHx j» tn' NITRO-ETHANE. 105 methyliodoethylammonium iodide. This iodide when treated with moist CH2_0 silver oxide yields the oxide i _i_ , which is contained in the sub- CH2 Nr(CH3)3 stance of the brain, and is called neurine. By the oxidation of neurine or .CO "0 choline, oxyneunne, i i , is obtained. It exists in the sugar CH2 N(CH3)3 beet (beta vulgaris), and is called betame. It is formed by heating mono- chloracetic acid with trimethylamine. By the action of silver nitrite on ethyl iodide, Nitro-ethane, C2H5"N02, is formed (isomeric with ethyl nitrous ester). It is a liquid boiling at 112°. The only other compounds of the C2 series which we shall mention are the following. Their methods of preparation will be found under the corresponding substances of the Ct series. Ethylphosphine, C2H5PH2, boils at 25°. Di-ethylphosphine, (C2H5)2PH, boils at 85'. Tri-etkylphosphine, (C2HS)3P, boils at 127°. They are all obtained according to the methods given under the cor- responding compounds in the methane series. They are easily oxidized, the ethylphosphine to ethy(phosphinic acid, C2H5PO(OH)2, di-ethylphos- phine to di-elhylphosphinic acid, (C2H5)2PO(OH), tri-ethylphosphiDe to tri-ethylphosphinic oxide (C2H5)aPO. Tri-ethylarsine, (C2H5)3As, boils at 140°, fumes in the air, and on warming in the air takes fire. Tri-ethylstibine, (C2H5)3Sb, boils at 158°, fumes in the air, and takes fire. Zinc-ethyl, (C2H5)2Zn, boils at 118°, and takes fire at once when ex- posed to the air. Mercury-ethyl, (C2H5)2Hg, boils at 159°. It is extremely poisonous. These compounds are all obtained by reactions analogous to those of the corresponding methyl compounds. The following esters are worthy of notice. Ethyl cyanide, C2H5~CN, is produced from potassium ethylsulphate and potassium cyanide. It is a liquid with an ethereal odor, boiling at 98°. On boiling with alkalis, it is decomposed into ammonia and pro- pionic acid. It is therefore the stepping-stone from the Ca to the Cs series : 106 C2 GROUP.—ETHANE COMPOUNDS. CH4-CN + 2 11,0 = C2H,"C00H -\- NH:1. Propionic acid It is hence propionitrile. Ethyl isocyanide is prepared from silver cyanide and ethyl iodide. It is a liquid with an offensive bitter odor, and boils at 79°. Acids decom- pose it at once into ethylamine and formic acid : C2II,~NC + 2 H„0 = Cllr/NH,) + CH202. Ethyl-cyanic ether, CON~C2H.„ is obtained by the dry distillation of potassium cyanate with potassium ethylsulphate. It is a colorless liquid with a strong odor which irritates the eyes. It boils at 60°. With it there is formed Ethyl-cyannric ether, C30:)N3 . (C2H5)3, which forms large crystals fusing at 85° and boiling at 276°. Potassium hydroxide decomposes both the cyanic and cyanuric ether into ethylamine and potassium carbonate : CON~C2H5 + 2 KHO = K,C03 -f C.H5NH2. Ethyl-isocyanic ether, CNO~C2H0, is formed from chlorcyan and sodium ethoxide: CNC1 + NaOC*H» = CNOC2H5 + NaCl. It is a liquid insoluble in water, and not distillable without decom- position. With potassium hydroxide it breaks into potassium cyanate and alcohol ; CNO"C2H5 + KHO = CNOK + C2H5OH. Ethyl mustard oil, CSN~C2H5, is produced in a manner analogous to the methyl mustard oil. It is a colorless liquid with the odor of mustard oil, boiling at 134°. With nascent hydrogen it passes into ethylamine and methylsulphaldehyde : CSN"C2H5 + 2 H* = CH..S + C\II5(NH2). Ethyl sulphocyanide, C>H5~SCN, is obtained by digestion of potas- sium ethylsulphate with potassium sulphocyanide. It is a liquid with an unpleasant odor, boiling at 146°. With nascent hydrogen, it yields cyan- hydric acid and ethylmercaptan : CNS _C2H5 + H2 = CNH + C2H5SH. C3 GKOUP. Propane Compounds. All compounds that contain three carbon atoms bound to each other, are derived from the hydrocarbon CH3~CH2~CH3, Propane. The diversity of the derivatives and the number of the isomers in this series is naturally greater than in the ethane series. It will only be necessary to consider the more important members of this class, since most of the compounds not mentioned here can be produced according to the analo- gous reactions of the corresponding members of the methane and ethane series. The replacement of an atom of hydrogen by a mono-valent atom, or atomic group, can produce two isomeric substances, depending on whether an atom of the group CH3 or CH2 is substituted. Bodies formed by substitution in the CH3 group are called propyl compounds, while those arising from substitution in the CH2 group are known as isopropyl compounds. Propane is but little known. The first derivative of it is propylene, CH3~CH=CH2, which is formed from allyl iodide and iodohydric acid : C3H5I + HI = C3H64-I2. Also from isopropyl iodide and potassium hydroxide : C3H714- KOH = C3H„ + KI 4- H20. Propylene is a gas. It unites with iodohydric acid to form isopropyl- iodide: CaH„ 4- HI = C3HJ = CH3-CHI-CHa. 107 108" C3 GROUP.—PROPANE COMPOUNDS. There is also a hydrocarbon of the C3 series corresponding to acetylene, viz., Allylene, CH3~C=CH. It is formed by the action of propylene bromide on an alcoholic solution of potassium hydroxide : CH3"CHBr-CH2Br4-2KHO = CH3"CHCH+2 KBr4-2 H20. It is a colorless gas, which, like acetylene, gives explosive pre- cipitates with an alcoholic ammoniacal solution of cuprous chloride or silver nitrate. It unites with bromine, forming two compounds, allylene dibromide, CH3~CBr=CHBr, and allylene tetrabromide, CH3~CBr.,~CHBr2. Propyl Chloride, CH3"CH2"CH2C1, or C3H7C1, is a color- less liquid, boiling at 47°. It is obtained from normal propyl alcohol by the action of gaseous chlorhydric acid. Isopropyl Chloride, CH3~CHC1~CH3, or C3H,C1, obtained from isopropyl alcohol. It boils at 37°. Both have a pleasant odor and resemble ethyl chloride. Propyl bromide, CH3~CH2~CH2Br, or C3H,Br, boils at 71°. Isopropyl bromide, CH3~CHBr~CH3, or C3H,Br, boils at 61°. Both are obtained from the corresponding alcohols by the action of bromhydric acid. They resemble ethyl bromide very much. Propyl iodide, CH3"CH2-CH2I, or C3HJ, boils at 102°. Isopropyl iodide, CH3~CHI~CH3, or C3H7I, boils at 80°. Both are obtained from the corresponding alcohols by the action of gaseous iodohydric acid, and are liquids resembling ethyl iodide, being colorless and having pleasant odors. Propylene chloride, CH3~CHC1~CH2C1, or C3H6C12 is formed on the contact of propylene and chlorine. It boils at 97°. By continued action of chlorine, all the hydrogen is replaced by chlorine. The other dichlorpropylenes are (1) CH3_CHCrCH2Cl, boils at 97°. (3) CH2C1-CH2-CH2C1, boils at 117°. (3) CH3-CH2-CHC12, boils at Go°. (4) CH3-CC12-CH3, boils at 70°. AH four have the formula C3HeCl2. Propyl Alcohol, CH3"CH2"CH2(OH), or C3H80, is formed ISOPROPYL ALCOHOL. 109 in small amounts in the fermentation of sugar, and is hence present in crude spirit. It can be formed synthetically from ethyl cyanide. Ethyl cyanide is converted into propionic acid by boiling with potassium hydroxide : C2HrCN 4- 2 H20 = C2H5_COOH -f NH3. The propionic acid is transformed into its lime salt, which, after being well dried at 100°, is distilled with calcium formate : C2H5COO\Pa , HCOO\Pq _ C2H5_CHO , CaC03 C2H5COO/Oa + HCOO/ba ~ C2H5"CHO + CaC03- The propionic aldehyde which is thus obtained is converted into propyl alcohol by the action of nascent hydrogen (sodium amalgam) : C2H5_CH04-H2 = C2HrCH2(OH), or CH3-CH2-CH2(OH). Propyl alcohol is a liquid with a pleasant alcoholic odor. It boils at 98°. All the reactions of both propyl and isopropyl alcohols are analogous to those of methyl and ethyl alcohols. Their halogen substitutions, ethers, and esters are formed in the same manner as the corresponding derivatives of the C2 group from ethyl alcohol. Isopropyl Alcohol, CH3"CH(OH)"CH3, or C3H80, is also formed in small amounts in the alcoholic fermentation of sugar, and is hence present in crude spirits. It is usually made artificially either from glycerol or acetone. Glycerol when heated with iodohydric acid yields isopropyl iodide : C3Hb03 4- 5 HI = C3H7I + 212 4- 3 H20, which when boiled with plumbic hydroxide and water gives isopropyl alcohol: 2 C3H7I + Pb(OH)2 = 2 C3HB0 4- Pbla. It is formed from acetone by reduction with sodium amalgam : CH3-CO_CH3 + H2 = CH3-CH(0H)-CH3. It is a liquid resembling propyl alcohol. It boils at 83°. The normal propyl alcohol yields propionic aldehyde, 110 C3 GROUP.—PROPANE COMPOUNDS. CH3"CH2"CHO, and propionic acid, CH3"CH2"COOH, on oxidation. By oxidation of isopropyl alcohol, however, acetone, CH3~CO"CH3, is first formed. By further oxidation, the mole- cule splits, giving acetic and formic acids. Owing, however, to the easy oxidizability of formic acid, acetic acid and carbonic acid are the final products. The oxidation of the alcohol, affords, therefore, a method of ascertaining whether the OH is bound to the CH3 or the CH2. The first oxidation product of propyl alcohol is Propion- aldehyde, CH3"CH2"CHO, or C3H60. It can also be obtained by distilling a salt of propionic acid with a salt of formic acid. It is a colorless liquid, soluble in but not miscible with water. It boils at 49°, and has a suffocating aldehyde odor. On ex- posure to the air it oxidizes to propionic acid. The first oxidation product of isopropyl alcohol is Acetone, Dimethyl-ketone, CH3"CO"CH3, or C3H60. Acetone is formed by the dry distillation of many organic substances e.g., sugar, tartaric acid, etc. It is a constituent of wood-spirit. It is also formed by the action of zinc methyl on acetyl chloride : (CH3)2Zn + 2 CH3_COCl = 2 CH3_CO"CH3 + ZnCl2. The best method of producing it is to submit salts of acetic acid to dry distillation : CH3"COONa _ CH3\ro ATfl ro 4- CH3-COONa ~ CH3/>C0 + Nai°°s- It is a limpid liquid with a peculiar odor. It boils at 58°, and is miscible with water, alcohol, and ether. Acetone breaks on oxidation into formic (carbonic) and acetic acids. It is converted by reduction with sodium amal- gam in aqueous solution into isopropyl alcohol : CH3_CO"CH3 4-30 = CH3"COOH + CHOOH Acetic acid Formic acid CH3-CO_CH3 4- H2 = CH3-CH(OH)-CH3 isopropyl alcohol ACETONE. Ill It combines with acid alkali sulphites, forming crystalline compounds. Chlorine acts directly on acetone with substitution of the hydrogen : C3H60, Acetone. C3H5C10, Monochloracetone, colorless liquid. Boils at 119°. It causes weeping. C3H4C120, Dichloracetone,boils atl20°. Its constitution isCHCl2~CO"CH3' The compound isomeric with it, CH2C1~C0~CH2C1, forms colorless crystals, fusing at 43° and boiling at 172-174°. C3H3C130, Trichloracetone, CC13"C0"CH3, boils at 170-174°. C3H2CUO, 1'etrachlor acetone. C3HC150, Pentachloracetone, boils at 190°. C3C160, Perchlora-cetone, boils at 200°. They are liquids with powerful odors. The higher chlorinated acetones, as the trichloracetone, etc., combine with water, forming crystal- line hydrates. By the action of gaseous chlorhydric acid, or concentrated sulphuric acid, acetone is condensed, several molecules uniting to one molecule with the elimination of water. The most important of these are : Mesityloxide, C6H10O, colorless liquid boiling at 130°: 2C3H60-H20=:CCH1„0. Phorone, C9HM0, fuses at 28° and boils at 196° : 3C3H60-2H20 = CJH140. Mesitylene, C9Hi2 : 3C3H60-3H20 = C9H12. We shall consider these compounds in the aromatic series. We see from the name of acetone, " dimethy 1-ketone," that there are other similar bodies, or " ketones," which contain, instead of the methyls, other hydrocarbon rests. Acetone may be considered as a compound in which the two active valences of CO are satisfied by two CH3's : Acetone Urea Carbonyl chloride One of the methods of producing acetone can easily be 112 C3 GROUP.—PROPANE COMPOUNDS. varied so as to produce mixed ketones. Zinc methyl and acetyl chloride give acetone ; zinc ethyl and acetyl chloride yield methylethyl-ketone; zinc ethyl and propionyl chloride form di-ethyl-ketone, and so on. Mixed ketones, and especially those of a higher order, can also be produced in another way. In the same manner that the distillation of an acetate affords acetone, the distillation of the salts of higher acids produce ketones of a higher order. Thus a salt of propionic acid yields on distillation di-ethyl-ketone: C2Hs-COONa _ C2H5\ro , - ro + C2H5-COONa ~ c'h'/00 + Na2C03- By the distillation of a mixture of an acetate and a propionate, methyl- ethyl-ketone is obtained : CH3-COONa _ CH3\ro , ~ ro + C2H5_COONa ~ C2H5/CU + n&^v3. If instead of an acetate, a formate is taken, the aldehyde of the acid is obtained, one of the free valences of the CO being neutralized by an H, the other by a hydrocarbon rest: CHrCOONa 3-COONa _ CH3\ m , Na ro HCOONa ~ H/LU + ^a2UJ3. The compound CI^\C0, as is evident, is CH3"CHO, or C2H40, alde- hyde. The production of many aldehydes and alcohols of higher orders depends on this method. Ketones are therefore aldehydes in which the H of the CHO is replaced by a hydrocarbon rest. The relations are seen at once from the following formulas : Methyl aldehyde, CO/|j. Ethyl aldehyde, Co/^H . Methyl ketone, Co/{^. The ketones, like the aldehydes, are reduced by sodium amalgam. They always yield the secondary alcohols : CH3-CO-CH3 + H4 = CH3_ CH(OH)-CH,. PROPIONIC ACID. 113 An intermediate product is formed in the reduction, however, by two molecules of the ketone taking up two atoms of hydrogen forming pina- cones. 2 (CH3)2=CO 4- H2 = (CH3)2=C(OH)-C(OH)=(CH3)2 = C6H1402. The pinacones are, hence, glycols. They are characterized by their losing easily a molecule of water when treated with acids, forming pina- colines: C6H1402 - H20 = C6H120 = (CH3)3EC_COCH3. The pinacolines are ketones. The pinacoline obtained from acetone is the tertiary methyl-butyl-ketone. Ketones unite like the aldehydes with cyanhydric acid, forming cyan compounds: (CH3)2=CO + HON = (CH3)2=C<^§ Ketones break on oxidation into two acids of lower carbon series : CH3-CO-CH3 + 30 = CH3_COOH 4- HCOOH. In this reaction the CO-group remains in combination with the lesser hydrocarbon rest: C4H9-CO-C2H5 + 30 = C4HB02 + C2H5_COOH. Propionic Acid. CH3~CH2~COOH, or C3H602, is the sec- ond oxidation product of normal propyl alcohol, and can be obtained by the oxidation of it. It is also formed by boiling ethyl cyanide with potassium hydroxide : C2HS_CN + KOH + H80 = C2H5"COOK + NH3. In nature it occurs in the sweat, in the fluids of the stomach, and in the blossoms of the milfoil. It is a liquid with a sharp odor resembling that of acetic acid. It distils at 140°. It is miscible with water, but is separated as an oil floating on the surface by dissolving salts in its solution. Chlorine, bromine, etc., substitution-products, the anhy- C IT ~CO\ dride, n2jj5"CO/^' propionyl chloride, CgH6"CO"Cl, as 8 114 C3 GROUP.—PROPANE COMPOUNDS. well as many salts and esters have been produced. Their properties are easily deduced from the corresponding acetyl compounds. Propyl glycol. There are two isomeric propyl glycols : 1) CH2(OH) 2) CH3 CH2 CH(OH) CH2(OH) CH2(OH). The first is the normal propyl glycol, the second the iso-propyl glycol. Both are oily liquids, the former boiling at 216°, the latter at 186°. Their chlorhydrins, acetates, etc., are known. By oxidizing the normal propyl glycol, there is produced the normal Propyl-glycollic Acid, CH2(OH)"CH2"COOH, or C3H603. It is a syrup very much resembling lactic acid. Its salts are, however, different from those of lactic acid. It can be pro- duced synthetically. Ethylene-glycol, CH2(OH)~CH2(OH), is converted by chlorhydric acid into ethyleneglycol hydrochloride CH2(0H)"CH2C1 glycol-chlorhydrin), which, in turn, by the action of potassium cyanide passes into the cyanide, CH2(OH)~CH2(CN). The cyanide on boiling with potassium hydroxide yields propylglycollic acid: CH2(OH)-CH2-CN + KHO + H20 = CH2(OH)-CHrCOOK + NH3. Propylglycollic acid, being a glycollic acid, is both alcohol and acid. On oxidation, the alcoholic group CH2(OH) is con- verted into carboxyl, CO(OH), forming malonic acid: CO(OH)_CH2-CO(OH). On heating, water splits out, yielding acrylic acid, C3H402 : CH2(OH)-CH2_COOH = CH2=CH-COOH+ H20. By the oxidation of isopropylglycol we obtain Isopropyl-glycollic Acid, Lactic Acid, CH3~CH(OH)~COOH. LACTIC ACID. 115 Lactic acid occurs in sour milk and in many plant juices. It is formed from sugar by a peculiar fermentation known as the " lactic fermentation," and is found in many sour, fermented liquids (sauerkraut, etc.). It can be formed synthetically from aldehyde "and cyanhydric acid. If aldehyde and cyanhydric acid are treated with concentrated chlor- hydric acid, a compound is formed which contains the elements of both aldehyde and cyanhydric acid : CH3-CHO + CNH = CH3-CH(OH)"CN. As it is a cyanide, the N can be replaced by the group 0(0 H), thus form- ing lactic acid : CH3-CH(OH)"CN + 2H20 = CH3"CH(OH)-COOH + NH3. In the same manner, therefore, that propylglycollic acid is formed from ethylene glycol, lactic acid is produced from alde- hyde, i.e., from the hypothetical ethylidene glycol: CH,-CH0. CH2/ We may consider mesoxalic acid as the last oxidation product of gly- cerol : COOH i Mesoxalic acid, C(OH)2, or C3H405, is obtained by treating dibrom- COOH malonic acid, COOH~CBr2~COOH, with silver oxide. It crystallizes in colorless, deliquescent prisms containing water of crystallization. It is dibasic and very unstable, oxidizing easily to oxalic and carbonic acids : COOH i COOH „ ^ ',0H>'+° = i00H+H'a COOH A reaction of glycerol with phosphorus di-iodide has just been noticed, by which allyl iodide, CH2=CH"CH2I, or C3H5I, is produced. If the iodine in this iodide is replaced by hy- droxyl (which can be effected by the well-known method of converting the iodide into an ester and then decomposing it by an alkali), the representative of a new class of alcohols is obtained. They contain a pair of doubly bound carbon atoms, and hence have two atoms of hydrogen less than the ordinary alcohols. They behave with the various reagents in the same manner as the ordinary alcohols, suffer the same substitutions, etc. In the presence of nascent hydrogen they take up two molecules of hydrogen. They also combine with halogens, viz.: C3H5OH + Br2 = CH8Br-CHBr-CH2OH. This class of compounds is called unsaturated. Those be- longing to the C3 series are the more important, and are de- 122 C3 GROUP.—PROPANE COMPOUNDS. rived from propylene, CH2=CH"CH3. They bear the name allyl, because some of them occur in members of the allium family. Allyl Iodide, CH2=CH"CH2I, or C3H5I, is obtained by the action of phosphorus di-iodide on glycerol. It is a colorless liquid with the odor of leeks. It boils at 101°. When treated with chlorine or bromine, iodine separates, and allyl tri- chloride, C3H5C13 (trichlorhydrin), or allyl tribromide, C3H5Br3 (tribrom- hydrin), are formed. The latter gives with potassium cyanide allyl tri- cyanide, C3H5(CN)3, which when boiled with potassium hydroxide affords tricarballylic acid, C3H5 (COOH)3. By digestion with a silver salt (the oxalate is usually employed) silver iodide and allyl oxalic ester are formed. The latter is decomposed by ammonia into allyl alcohol and oxamide : CO(OC,H,) CO.NH.) H0H CO(OC3H5) CO(NH2) Allyl Alcohol, CH8=CH_CH8OH, or 03H6O. Allyl alcohol is isomeric with both propyl aldehyde and acetone. It is found among the products of the dry distillation of wood. It can be made, as just shown, from allyl iodide, or by heating gly- cerol with oxalic acid at 200°. In this case the formic ester of glycerol is formed, which at 200° breaks into carbonic acid and allyl alcohol, water being eliminated : C3H5(OH)2-0-CHO = C3H6OH + C02 + H20. Allyl alcohol is a colorless liquid with a peculiar and pene- trating odor. It boils at 97°, is combustible, and miscible with water. It dissolves sodium with evolution of hydrogen, forming sodium alloxide, C3HgOXa, which with allyl iodide gives the allyl ether, C3H5~0~C3H5. Allyl ether is a liquid boiling at 82°, and not miscible with water. Oxidizing agents convert allyl alcohol into the correspond- ing aldehyde (acroleine) and acid (acrylic acid). The oxida- tion of the alcohol is a method but poorly suited for the ALLYL ALCOHOL. 123 production of acroleine or acrylic acid, since the greater part of the allyl alcohol is completely decomposed, breaking into acetic and formic (carbonic) acids. Acroleine, Acrole, CH2=CH"CHO, or C3H40. Acroleine is made by heating glycerol to which glacial phosphoric acid or primary potassium sulphate has been added for the purpose of promoting the reaction. The glycerol loses two molecules of water : C3H803 = C3H40 + 2H20. It is a liquid boiling at 52°. Its odor is extremely unpleas- ant and attacks the mucous membranes very strongly. In water it is difficultly soluble, swimming like a layer of oil upon its surface. It changes gradually, when kept in closed vessels, into a polymeric body called disacryl, a white, flocculent sub- stance, the molecular weight of which is not known. It unites directly with chlorhydric acid, forming a body known as acro- leine hydrochloride, but which is really CH3~CHCl~CHO. With sodium amalgam it does not form allyl alcohol, but propyl alcohol : CH2=CH_CHO + 2H2 = CH3_CH2-CH2OH. As acroleine is an aldehyde, it gives all the characteristic reactions of aldehydes, taking up oxygen very easily and pass- ing into the corresponding acid. By boiling it with a silver salt a silver mirror is obtained, and also the silver salt of Acrylic Acid, CH2=CH"COOH, or C3H402. Acrylic acid is obtained in the free state by decomposing its silver salt with hydrogen sulphide. It is a liquid boiling at about 140°, with a piercing acid odor. It is a monobasic acid. Its salts are mostly crystalline. On oxidation, it breaks into acetic acid and formic or carbonic acids. Sodium amalgam reduces it to propionic acid : C3H402 + H2 = C3H602. 124 C3 GROUP.—PROPANE COMPOUNDS. It unites easily with bromine, forming dibrompropionic acid, and with iodohydric acid to mono-iodopropionic acid. By distilling allyl iodide with potassium cyanide we obtain Allyl cyanide, C3H5~CN. It occurs in commercial mustard-oil, and is a colorless liquid boiling at 118°. With potassium hydroxide it evolves ammonia and passes into crotonic acid: C3HrCN + KHO + H20 = C3HrCOOK + NH3. It is therefore called crotonic nitrile. By digesting allyl iodide with silver cyanide we obtain Allyl isocyanide, C3H5~NC, which is a liquid with an offensive odor, boiling at 106°. Acids decompose it into formic acid and allyl-amine : C3H5NC + 2 H20 = C3H6NH2 + CH202. Allyl Mustard-Oil, Mustard-Oil par excellence, Allyl Thio- carbyl-amine,C3H5~~N=CS. Mustard-oil does not exist ready formed in nature, but is produced by a peculiar fermentation when the seeds of the black mustard are moistened with water. After removing the oil from the black mustard seeds by pressing, they are moistened with water and allowed to remain moist several days, after which they are distilled with water. The mustard-oil can also be pro- duced from allyl iodide and potassium sulphocyanate. Mustard-oil is a colorless liquid boiling at 148°. It has a piercing odor which causes weeping. In water it is insoluble. It produces blisters on the skin. Ammonia converts it into allylsulpho-urea, or thiosinamine, CS< ,/NH-C3H5 '\NH2 By heating with lead oxide and water it yields di-allylurea, or sinapoline, 'NH-C3H5 co\nh"c!h!- Allyl sulphocyanate, C3Hft~SCN, is formed by the action of rotassium ALLYL SULPHIDE. 125 sulphocyanate on allyl iodide in the cold. It is a liquid with a peculiar odor, which on distillation is converted into mustard-oil. C TT \ Allyl Sulphide, Garlic Oil, pi3tt5 /S, is contained in the bulbs of the garlic {allium sativum), and is obtained by dis- tilling them with water. It can also be produced from allyl iodide and potassium sulphide, K2S : 2 C3H5I + K2S = (C3H5)2S + 2 KI. It is a colorless liquid with the odor of garlic. It boils at 140° and forms crystalline compounds with several metallic salts, as mercuric chloride. We shall only mention a few of the remaining compounds of the pro- pane series, since their formation and their more important properties can be deduced from the corresponding compounds of the ethane series. Propylamine, CH3~CH2"CH2(NH2), boiling at 50°. Isopropylamine, CH3~CH(NH2)~CH3, boils at 32°. Both are alkaline liquids with ammoniacal odors. They form well- characterized salts with acids. Amidopropionic acid, alanine, CH3-CH(NH2)~COOH, is obtained by boiling aldehyde-ammonia and cyanhydric acid with chlorhydric acid : CH3-CH(NH2)(OH) + HCN + H20 = CH3-CH(NH2)"COOH + NH3. Alanine crystallizes in rhombic prisms, which on heating decompose into ethylamine and carbonic acid : C3H7N02 = C2H,N + C02. Uric acid and its derivatives properly belong to the C3 group, as they do not contain more than three carbon atoms bound to each other, but a clearer understanding of this complicated class can be obtained by con- sidering them later on as a class by themselves. C4 GEOUP. Butane Compounds. In the butane group there are of course a greater number and variety of isomers than in the preceding groups. The base of the series itself, Butane, exists in two modifications, depending upon whether an Hof a CH3 or a CH2, of propane, CH3 CH2 CH3, is substituted by a CH3. We have, therefore : CH3"CH2"CH2_CH3, Butane, and CH3~CH~CH3, Isobutane. CH3 It is also evident that the result of a substitution of an H in the butanes by an element, or atomic complex, will depend on whether the substitution takes place in a CH3 or a CH2 of propane, or a CH3 or a CH in the isopropane. We see hence that in case of a monosubstitution of the butanes there are four isomers. The number of isomers increases rapidly when several hydrogen atoms are substituted. We have not space to note all the possible substitutions of this series, many of which have not yet actually been obtained, and must be con- tent, therefore, to consider only the more important ones. 1) Normal butyl chloride, CHrCH2-CH2-CH2Cl, or C4H9C1, is ob- tained from the corresponding alcohol by the action of gaseous chlorhy- dric acid gas. It boils at 78°. 2) Pseudobutyl chloride, or secondary butyl chloride, 126 BUTYL ALCOHOL. 127 CH3-CH2-CHC1-CH3, or C4H8C1. It boils at 66°. /CH3 3) Isobutyl chloride, CH^-CH3 , or C4H0C1. It boils at 69°. \CH2C1 /PIT 4) Tertiary butyl chloride, CCI^-ChI, or C«H,C1. It boils at 50-51°. \CH3 All four of them are colorless liquids with pleasant odors. 1) Normal butyl iodide, CH3~CH2~CH2~CH2I, obtained like the chlo- ride. Boils at 130°. 2) Secondary butyl iodide, CH3~CH2~CHI~CH3, boils at about 80°. /CH3 3) Isobutyl iodide, CH^—CH3 , boils at 121°. \CH2I /CH3 4) Tertiary butyl iodide, CI;—CH3, boils at 99°. \CH3 1) Normal butyl alcohol, propyl carbinol, CH3~CH2~CH2~CH2OH, C4H9OH, or C4Hi0O. It is obtained from the corresponding butyric acid by the method described under propyl alcohol. Calcium butyrate is mixed with calcium formate and submitted to dry distillation. The butyraldehyde is separated from the distillate and transformed into butyl alcohol by the action of nascent hydrogen. It can also be produced from glycerol by a peculiar fermentation. It is a colorless liquid with an odor partly like alcohol and partly like fusel oil. It boils at 116°, and is soluble in water, although not miscible with it in all proportions. Its properties are analogous to those of the preceding alcohols. On oxidation, it passes into butyraldehyde and nor- mal butyric acid. 2) Secondary butyl alcohol, ethyl-melhyl-carbinol, CH3_CH2-CH(OH)-CH3, C4H9OH, C4H10O. It is formed from erythrol by the action of iodohydric acid, by a re- action analogous to the formation of isopropyl alcohol from glycerol (compare p. 120): C4H,„04 + 7 HI = C4H.1 + 4 H20 + 6 I. Erythrol Sec. butyl iodide C4HJ + KOH = C4HuOH + KI. 128 C4 GROUP.—BUTANE COMPOUNDS. It is also made indirectly. Dichlorether, CH2CrCHCrO"C2H5, is converted, by treatment with zinc ethyl, into ethylmonochlorether, CH2CrCH(C2H5)-0-C2H,. This compound is then transformed into butyl iodide and ethyl iodide by treating with iodohydric acid : CH2Cl-CH(C2H5)-0-C2H5 + 4 HI = CHrCHrC2H5 + C2H3I + HCl + H20 + I2. The butyl iodide is then converted into the alcohol by the action of moist silver oxide : 2 C2H5-CHI-CH3 + Ag20 + H20 = 2 C2H5-CH(OH)"CH3 + 2 Agl. The formula C2H5"CHI"CH3 is CH3~CH2~CHI"CH3, or secondary butyl iodide, and the alcohol obtained from it is hence CH3~CH2-CH(OH)-CH3. Secondary butyl alcohol is a colorless liquid with a pleasant odor. It boils at 98°. It is soluble in water, but not miscible with it. It loses the elements of water easily and passes into butylene, C'H3~CH=CH-CH3. By oxidation it is transformed into the ketone: CH3-CH2-CO-CH3, or CO<^~CH3, methyl-ethyl ketone. By further oxidation it breaks into two molecules of acetic acid. 3) Isobutyl Alcohol, Isopropyl Carbinol, /CH3 CHf-CH3 , C4H9OH, C4H10O, \CH2OH is formed in small amounts in the alcoholic fermentation of sugar, and hence occurs in crude spirits. In the rectification of crude spirits, it goes over, after the ethyl alcohol has been distilled, with the fusel oil, from which it is separated by frac- tional distillation. It is a liquid which boils at 107°, and is soluble in, but not miscible with water. Its odor resembles that of fusel oil. By oxidation it is converted first into isobutyraldehyde and then into isobutyric acid. ALCOHOLS. 1.29 4) Tertiary butyl alcohol, trimethyl carbinol, /CW C(OH)A?H3, C4H0OH, C4H10O. \CH3 It is made from acetyl chloride and zinc methyl. By allowing the mixture to stand some time at a gentle heat, a com- pound of one molecule of acetyl chloride with two molecules of zinc methyl separates in crystals. Water decomposes this compound into tertiary butyl alcohol, zinc hydroxide, and methane : 2 rCH3-COCl+ 2 cH3^>Znl + 6 H20 = 2 CHrC(OH)/gg| -Acetyl chloride Zinc methyl J Tertiary butyl alcohol3 + 4 CH4 + 3 Zn(HO)2 + ZnCl2. The alcohol is an oily liquid solidifying at the ordinary temperature in crystals. It boils at 82°, and has a characteristic camphor-like odor. It breaks easily into pseudobutylene, CH^C^kS3, and water. On ox- idation it yields chiefly acetic and propionic acids besides carbonic acid, i.e., oxidized formic acid. We have now become familiar with three kinds of alcohols. The first are the proper, normal, or primary alcohols. They are characterized by containing the group CH2OH, and give on oxidation an aldehyde and an acid. As the OH replaces an H of the group CH3, there remain two H's which can be oxidized. To this class all the normal alcohols and also the isobutyl alcohol belong. The second group of alcohols is called secondary. They are characterized by the group CHOH. The hydroxyl replaces an H in a CH2, thus leaving only one oxidizable H. On oxidation they do not give an aldehyde and an acid, but yield a ketone, which by continued oxidation breaks into two acids of lower carbon content, the molecule breaking at the carbon atom which binds the hydroxyl: CH3-CH2_CH(OH)_CH3 yields acetic acid. Secondary butyl alcohol Isopropyl alcohol and the secondary butyl alcohol belong 9 130 C4 GROUP.—BUTANE COMPOUNDS. to this class. They lose the elements of water easily, yielding a hydrocarbon of the formula C„H2,1, e.g.: CH3-CH2_CH(OH)_CH3 = CH3_CH=CH-CH3 + H20. The third class of alcohols, which are known as the tertiary, is characterized by the group C~OH, formed by the replace- ment of an H in the group CH. The hydroxylated carbon does not bind any oxidizable hydrogen, and by oxidation they break at once into acids of lower carbon content: /CH3 C(OH)(—CH3 yields acetic and formic acids. \CH3 The tertiary alcohols have also the tendency to drop out the elements of water and pass into hydrocarbons of the formula CnH2„, e.g.: CH3_C(OH)"CH3=CH3"C=CH2 + H20. CH, CH, The most convenient method of naming the alcohols is to consider them as derivatives of methyl alcohol, or carbinol, viz. : H\ H^C. OH CH3 . OH Carbinol Methyl alcohol \ CH. ch;^c . OH hV C3H7.OH Isopropyl alcohol Dimethyl carbinol CH H -^C. OH H / C2H5 . OH Ethyl alcohol Methyl carbinol ;C.OH C3H7^ H H / C4H9.OH Butyl alcohol Propyl carbinol C2H5v H ^C. OH H / C3H7 . OH Propyl alcohol Ethyl carbinol C2H5\ CH3-^C. OH H V C4H9.OH, etc. Sec. mityl alcohol Methylethyl carbinol The other bonds of the hydroxylated carbon atom must, of course, be satisfied by hydrocarbon rests : BUTYRIC ACID. 131 ~CH2~OH binds one carbon atom, by one bond; =CH~OH binds two carbon atoms, each by one bond ; =C~OH binds three carbon atoms, each by one bond. Certain of the isomeric alcohols can be transformed into each other. The primary pass into the secondary, and these into the tertiary. In some cases a primary alcohol can be transformed into another isomeric primary alcohol. Among the four butyl alcohols described, there are only two which yield aldehydes. The normal butyl alcohol gives the normal b u tyraldehyde, CH3-CH2-CH2-CHO, or C4H,0, a liquid with an aldehyde-like odor, C(OH)-COOH. Both of the possible dicarboxylic acids of the C4 group are known: SUCCINIC ACID. 133 COOH CH2 /COOH i 8 and CHeCOOH CH2 \CH3 COOH The former is succinic acid, the latter isosuccinic acid. Succinic Acid, COOH"CH2"CH2-COOH, or C4H604. This acid exists in amber, in many plants, and in the animal or- ganism. It is formed in small amounts in the alcoholic fermentation of sugar, and also by the reduction of malic acid (p. 134) and tartaric acids by iodo- hydric acids : C4H605 + 2 HI = C4H604 + H20 +12 Malic acid C4H606 + 4 HI = C4H0O4 + 2 H20 + 212. Tartaric acid It can also be produced from ethylene cyanide, C2H4(CN)2 : CH2"CN CH2"COOH i 4-4H20 = i + 2NH3 CH2-CN^ CH2"COOH^ It is generally made by the distillation of amber. Succinic acid crystallizes in monoclinic prisms, which fuse at 180° and boil at 235°, with partial formation of the anhy- dride. It is soluble in water and hot alcohol. Its vapors are irritating, causing coughing. It is a dibasic acid, forming two series of salts. The succinates of the alkaline metals are easily soluble in water, while those of the other metals are difficultly soluble, or altogether insoluble. CH2-COCl With phosphorus pentachloride it gives succinyl chloride, i -CQC], an oily liquid boiling at 190°, which fumes in the air and is decomposed by water, and with ammonia yields succinamide. CH2"CO(NH2) Succinamide, ■ „ , crystallizes in white needles, which are CH2"CO(NH2) J 134 C4 GROUP.—BUTANE COMPOUNDS. easily soluble in water. On heating, ammonia splits out, forming succini- CH2"CO^ mide, i /NH, which crystallizes in colorless needles, containing one molecule of H20. It fuses at 125°, and boils at 287°. Bromine reacts with succinic acid, replacing hydrogen. Monobromsucci- nicacid, C2H3Br(C02H)2, crystallizes in warty concretions. Dibromsucci- nic acid, C2H2Br2(C02H)2, is also a crystalline body. By repeated distillations, succinic acid is converted into CH -CO\ Succinic Anhydride, i >0, which forms colorless crys- 3 CH2~CO/ J tals fusing at 120° and boiling at 250°. On boiling with water it passes back into the acid : CH2_CO\ ^ „ ^ CH "COOH . 2 >0 + H20= . 2 CHa"CO/ 2 CH2_COOH Succinic acid is converted into normal butyric acid by reduction : CHrCOOH „ CHrCH H2 + 3H2 = . ~2 3 +2H90. CH2"COOH^ 8 CH2"COOH^ /pooh Isosuccinic acid, methylmalonic acid, CH3~CH<: pXXS, or C4H604. This acid is produced from cyanpropionic acid : CH3-CH^gJOH + 2 H20 = CH3-CH<^°°g + NH3. It forms crystals which fuse at 130", and are more easily soluble in water than ordinary succinic acid. At 150° it falls into propionic and carbonic acids. The hydrogen in both the CH2-groups of succinic acid can be replaced by hydroxyls, thus yielding a series of dicarboxylic acids containing more oxygen than succinic acid. CH(OH)"COOH Malic Acid, > -^^^^ • This acid occurs in many CtL2 COOH MALIC ACID. 135 sour fruits, as apples, gooseberries, mountain-ash berries, etc. It can be made from succinic acid by boiling bromsuccinic acid with silver oxide, and from tartaric acid by heating with iodohydric acid. It is usually obtained from the berries of the mountain ash. It is a difficultly crystallizable, solid mass, which is deli- quescent, easily soluble in water and alcohol, fuses at 100°, and decomposes at a higher temperature. It is dibasic, and forms two series of salts. It stands in the same relation to succinic acid as glycollic acid does to acetic acid. Iodohydric acid con- verts it into succinic acid. When digested with potassium chromate, carbonic acid is eliminated, and it passes into ma- lonic acid : CH(OH)_COOH ^ COOH i + 02 = i + C02 + H20. CH2"COOH 2 CH2"COOH r s ^ 2 It suffers a peculiar fermentation in contact with yeast, yielding succinic, acetic, and butyric acids. The malic acid occurring in nature polarizes to the left, while that made from succinic acid is optically inactive. These physical differences appear even more sharply defined in the case of tartaric acid. One of the amido-derivatives of malic acid is worthy of atten- CH2_CO(NH2) tion, viz., Asparagine, ■ or C.H8N20,. r CH(NH2)-COOH' 4 8 2 3 It occurs in asparagus, liquorice, and in the germs of many plants, and crystallizes in transparent prisms containing one molecule of water. It is soluble in water, and combines with both acids and bases. In contact with putrid cheese, it is reduced to succinic acid. Nitrous acid converts it into malic acid: CH2-CO(NH2) CH2_COOH CH(NH2)"COOH + 2 3 ~ CH(OH)_OOOH + H„0 + 2N 136 C4 GROUP.—BUTANE COMPOUNDS. By boiling with acids or alkalis, the amido-group is replaced by the hydroxyl-group, forming aspartic, or amidosuccinic acid: CH2"CO(NH2) CH,-CO(OH) i + H20 = i + NH3. CH(N/H2)-COOH CH(NH2)"COOH ^ Both asparagine and aspartic acid are optically active. From the isobromsuccinie acid, isomalic acid, CH3~C(OH)<^ nQ2jri has been obtained by the action of silver oxide. CH(OH)"COOH Tartaric Acid, i , or C,HfiOB. 'CH(OH)-COOH 4 6 6 Tartaric acid occurs in many fruits, particularly in grapes. It is formed by the oxidation of milk-sugar, and by boiling dibromsuccinic acid with silver oxide. Young wine on standing deposits a thick crust on the sides of the casks, which consists of the acid tartrates of potassium and calcium. Both of the salts were originally in solution in the must; but, as the wine becomes richer in alcohol, the salts which are insoluble in alcohol are precipitated. This deposit is called crude argot, and is the material from which tartaric acid is made. Tartaric acid crystallizes in monoclinic prisms, easily soluble in alcohol and water. It forms two series of salts. It tastes strongly acid. When heated in the air, it gives an odor of burnt sugar. It fuses at 135°, forming, on cooling, a gummy mass, meiatartaric acid. The salts of this acid are converted into salts of ordinary tartaric acid by boiling with water. On heating tartaric acid to 150°, water is eliminated, and ditartaric acid, C(,Hl0Oii, an amorphous deliquescent mass is formed. On further heating to 180° more water is eliminated, and tartrelic acid, or tartaric anhydride, CMH8Oi0, is produced. On being sub- mitted to dry distillation, it yields a large number of products, of which we shall only mention pyroracemic acid, C3H403, and pyrotartaric acid, C5H604. With nitric acid it forms a nitric ester, called nitrotartaric acid, CH(ON02)"COOH i , which decomposes on evaporation of its aqueous solu- tion into carbonic acid, nitrous anhydride, and tartronic acid, CsH408 (p. 121). TARTARIC ACID. 137 Tartaric acid on being heated with iodohydric acid is reduced to succinic acid : C4H606 + 2 HI = C4H605 + H20 + I2 C4H606 + 4 HI = C4H604 + 2 H20 + 2 I,. The most important tartrates are : Hydrogen Potassium. Tartrate, Argol, Cream of Tartar, C4H5KOfi. It is difficultly soluble in cold water. Its forma- tion is a characteristic test for tartaric acid. Hydrogen Ammonium Tartrate, C4H6(NH4)06, is also diffi- cultly soluble in cold water. The neutral salt is easily soluble. Potassium Tartrate, C4H4K206, forms crystals easily sol- uble in water. It is changed into the acid salt by boiling with water. Potassium Sodium Tartrate, Rochelle Salts, C4H4KNa06 4H20. This salt is formed by saturating bitartrate of potash with sodium carbonate. It forms large transparent rhombic columns, which are easily soluble in water. Calcium Tartrate, C4H4Ca04 + 4H20, is almost insoluble in cold water. It is soluble in cold potassium hydroxide solu- tion, and is precipitated by boiling. This behavior of the calcium salt is characteristic of tartaric acid, and is used to detect its presence. Potassium Antimony Basic Tartrate, Potassium Antimonyl Tartrate, Tartar Emetic, C4H4(SbO)K04 + \ H20. It is obtained by boiling potassium bitartrate with antimony oxide. Colorless rhombohedrons and octahedrons, which are quite soluble in cold water, and cause nausea. It loses a molecule of water at 200°, yielding the compound C4H2KSbOfi. In this salt, C4H4K(Sb0)06, one of the hydrogen atoms of the carboxyl is replaced by K, the other by the group SbO, antimonyl. There are four physically different modifications of tartaric acid, the chemical properties of which, however, are identical. 1) Inactive Tartaric Acid, which has no effect on the ray of polarized light. 138 C4 GROUP.—BUTANE COMPOUNDS. The tartaric acid obtained from dibromsuccinic acid belongs under this head. It is also formed by the oxidation of sorbine, and together with racemic acid by heating ordinary tartaric acid to 165°. On heating with water to 175°, it is partly converted into racemic acid. It is easily soluble in water. Its acid potassium salt is also easily soluble. 2) Racemic Acid, which does not act on the "polarized ray, but can be converted into optically active acids. If ammo- nium sodium racemate is allowed to crystallize, two sets of crystals are formed which are exactly the same, except that one is the reflected image of the other, the hemihedral faces being developed on opposite sides of the crystals. By separat- ing these crystals and converting them into the free acid, we find that one kind gives the 3) Dextrotartaric Acid, which turns the polarized ray to the right, and the other the 4) Levotartaric Acid, which turns the ray of polarized light the same number of degrees to the left. The ordinary tartaric acid is the dextrotartaric acid. Some- times racemic acid in the form of its potassium and calcium salts is also found in argol. Racemic acid is formed by the oxidation of mannite, dulcite, and mucic acid. Also by the action of cyanhydric acid and chlorhydric acid on glyoxal. An addition-product of glyoxal with cyanhydric acid is formed, which is decomposed by the chlorhydric acid : CHO-CHO + 2 HCN = CN"CH(OH)-CH(OH)-CN, CN-CH(OH)-CH(OH)-CN" + 4 H20 = C02H-CHOH-CHOH"C02H + 2NH3. It is also formed, together with inactive tartaric acid, by heating dextro- tartaric acid with water at 175°. It crystallizes in long, rhombic, efflores- cent crystals. Its salts differ but little from those of dextrotartaric acid. A trihydric alcohol, or butylic glycerol, is not known. A tetrahydric alcohol, which is the richest alcohol in oxygen in this series, is, however, known. ~ , , CH(OH)~CH2(OH) n TT ^ Erythrol, Erytlrite, fe 0H -j^ 0 ', or C,HlaO„ ERYTHROL. 139 occurs in nature. It is obtained from erythrin, a constituent of certain lichens. It forms large, transparent crystals, with a sweet taste, which fuse at 120°, and are easily soluble in water. With nitric acid it give a nitric ester, C4H6(ON02)4, analogous to nitroglycerol, and which is violently explosive. Iodohydric acid converts it into secondary butyl iodide (as glycerol into CH(OH)"COOH isopropvl iodide). It can be oxidized to erythric acid, i , F ^J CH(OH)"CH2(OH) which stands to it in the same relation as glyceric acid to glycerol. Although tartaric acid has not been produced from erythrol, it may be regarded as the dicarboxylic acid of it, and thus stands in the same rela- tion to it as oxalic acid to glycol. There are several oxygen derivatives of the C4-group which are un- saturated compounds, and which stand in the same relation to the corre- sponding butyl compounds as do the allyl compounds to the propyl derivatives. Crotonaldehyde, C4H60, is produced by the condensation of ethyl al- dehyde. Its constitution is CH3"CH=CH-CHO. CH3"CHO + CH3"CHO = CH3-CH=CH_CHO + H20. It is a liquid with a piercing odor, boiling at 105°. By oxidation it is converted into crotonic acid, CH3"CH=CH"COOH, which fuses at 72° and boils at 184°. This acid can also be obtained from allyl cyanide and potassium hydroxide. Besides the solid crotonic acid, there is the isocrotonic acid, CH2=CH-CH2_COOH, a liquid which boils at 172°, and which during distillation is partly de- composed into solid crotonic acid and methacrylic acid, CH2=C\COOH, which boils at 160° and solidifies at 16°. If malic acid is heated to 150°, water is eliminated and it is converted into CH-COOH Fumaric acid, !■„_„„„„ > or C4H404. CH COOH 140 C4 GROUP.—BUTANE COMPOUNDS. CH(OH)"COOH CH "COOH i ' =11 +H20. CH2_COOH CH"COOH Fumaric acid occurs in many plants, as Iceland moss, fumaria offici- nalis, etc. It crystallizes in small needles, which are difficultly soluble in cold water, easily in alcohol. It volatilizes at 200°, and is converted into the isomeric maleic acid. /CH2"C00H\ Maleic acid, ( i ). It fuses at 130°, and is easily soluble in \C"COOH / J water. It is converted back into fumaric acid when heated for some time at 130°. Both of these acids give succinic acid by reduction. They are both characterized by the small amount of hydrogen they contain. The constitution of this acid was formerly supposed to be CHg-C^coQ.jp hut the first formula better represents certain of its reactions. The existence of a di-valent or unsaturated carbon atom in the molecule, has, however, not yet been established with certainty. Of the remaining compounds of this group we shall mention only: Butylamine, CHVCH2-CH2-CH2(NH2), or C4H9(NH2), which boils at 75°, and Isobutylamine, CH3~CH^g3 or C4H9(NH2), which boils at 70°. Both are liquids with ammoniacal odors and basic proper- ties. They form crystalline salts. C6 GROUP. Pentane Compounds. The saturated hydrocarbon C5H12, which forms the base of the Pentane or Amyl series, exists in three isomeric modi- fications : CH3 CH2 CH2 CH2 CH3, OH,-OH,-CH<(g|j, CH3 and CH3-C_CH3. CH3 The number of isomeric substitutions in this series is hence much greater than in the preceding ones. Only a few of them are known, and the constitution of many of these has not been determined with certainty. There are eight possible alcohols, of which seven are known; three of them are primary, three secondary, and one tertiary. 1) Normal amyl alcohol, butyl-carbinol, CH3-CH2-CH2-CH2-CH2(OH), or C5H,,0, is made from normal valerianic acid. It is a colorless liquid with a suffocating odor. It boils at 137°. This alcohol yields a chloride, C5Hi iCl, which boils at 107°, a bromide (b. p. 129°), and an iodide (b. p. 155°). On oxidation, it is converted into normal valeraldehyde and normal valerianic acid. 141 142 C5 GROUP.—PENTANE COMPOUNDS. 2) Ordinary Amyl Alcohol, Isobutyl-Carbinol, ^°^>CirCH2-CH2(OH), or C5H120. This alcohol is the chief constituent of fusel oil. It is formed during the alcoholic fermentation of sugar, and is separated from the crude spirit by distillation. It is a colorless liquid boiling at 131.4°. Its odor is disagreeable and causes cough- ing. The chloride produced from it, CgHjjCl, boils at 99°, the iodide at 147°. Nearly all derivatives have been produced from this alcohol which have been obtained from ethyl alcohol. We shail omit the description of them, since their chief properties will appear on comparison with the cor- responding compounds of the ethane series. By oxidation it is converted into valeraldehyde and valeri- anic acid, the properties of which are of course different from those of the normal aldehyde and acid. 3) Secondary butyl-carbinol. Fusel oil contains a second amyl alcohol which differs from the preceding chiefly in its polarizing to the left. It has the constitution, CH3-CH2-Ch/q^oh, and boils at 127°. 4) Isopropylmethyl-carbinol, CH3_CH(OH)-Ch/^, orC5H120, is a secondary alcohol. It is formed by the reduction of isopropylmethyl-ketone, and is a liquid difficultly soluble in water, boiling at 113°. 5) Propylmethyl-carbinol, CH3-CH2-CH2_CH(OH)_CH3, or C5H120, boils at 119°. 6) Diethyl-carbinol, C2H5_CH(OH)-C2H5, or C5H120, boils at 117°. 7) Ethyldimethyl-carbinol, amylene hydrate, CH3~CH2~C(QH)~CH3, CH3 or C5H120, boils at 103°. This alcohol yields only acetic acid on oxidation. The following aldehydes are known : 1) Normal Valeraldehyde, CH3(CH2)3_CHO, or C5Hl0O, boiling at 102°, and ORDINARY VALERIANIC ACID. 143 2) Ordinary Valeraldehyde, (CH3)2CH"CH2"CHO, or C5H10O, boiling at 92°. Both of these aldehydes are liquids possessing the charac- teristic suffocating odor of ordinary aldehyde. Three of the four possible acids are known. 1) Normal Valerianic Acid, CH3"CH2"CHs"CH2°COOH, orC6H10O2. This acid is produced by boiling butyl cyanide with al- coholic potassium hydroxide. It is somewhat soluble in water, boils at 185°, and has an odor resembling butyric acid. The properties of both the acid and its salts differ from those of the following acids and salts. 2) Ordinary Valerianic Acid, ggs^oH-CHg-COOH, orC5H10O2. This acid occurs in the root of the valerian, and, together with butyric acid, in putrid cheese. It is made either from the valerian root, or by oxidation of ordinary amyl alcohol. It is a liquid boiling at 175°, and is lighter than water. Its odor resembles that of putrid cheese. The hydrated acid con- tains one molecule of water and boils at about 165°. It forms crystalline salts. The more important salts of valerianic acid are the following : Bismuth valerianate, Bi(OH)2C5H302 (a basic salt constituted analo- gously to the basic bismuth nitrate). It is a white powder insoluble in water, and has the odor of valerianic acid. Zinc valerianate, Zn(C5H,02)„ is made by dissolving zinc carbonate in valerianic acid. It forms white crystals difficultly soluble in cold water. They have a sweet taste and an odor of valerianic acid. 3) Methyl-ethyl-acetic acid. The secondary butylcarbinol gives an acid on oxidation which differs from the above valerianic acid in polarizing OFT \ strongly to the right. Its constitution is probably q ^ ^CH~COOH, methylethylacetic acid. 144 C6 GROUP.—PENTANE COMPOUNDS. CH3\ 4) Tri-methyl-acetic acid, CH3^C"COOH, or C5H10O2, is obtained by CH,/ digestion of tertiary butyl iodide with potassium cyanide, and decomposi- tion of the cyanide, which is formed, by potassium hydroxide : CH3-CI-CH3 + KCN = CH3-C(CN)-CH3 + KI CH3 v CH3 CH3_C(CN)-CH3 + KHO + H20 = CH3-C(COOK)-CH3 + NH3. CH3 CH3 It is a solid mass fusing at 34° and boiling at 161°. There are a number of glycols and glycollic acids known in this series. Three dicarboxylic acids of the formula, C5H„04, have been obtained: 1) Glutaric acid, C02H-CH2-CH2_CH2-C02H, is formed by the decomposition of the normal propylene cyanide : cn-ch2-ch2-Ch2-cn. It forms large, easily soluble crystals which fuse at 97°. 2) Pyrotartaric acid, CH3~Ch/S2 -qq jj' is produced by the de- composition of the ordinary propylene cyanide, CH3~CH(CN)"CH2(CN), and also by the dry distillation of tartaric acid. It forms small trans- parent crystals fusing at 112°. C0 >C0 \nh-c---nh/ i.e., two urea rests bound together by the group C \ It is easily -or/ to be understood that the group C30 is converted into mesoxalic acid by oxidation, and finally into oxalic and carbonic acids. Alloxan, CO<^Jg-{$£>CO, or CCH(OH)- Dialuric acid contains, together with the rest of urea, the rest of tartronic acid, COOH"CH(OH)"COOH, and is hence tartronylurea, just as alloxan is mesoxylurea, and parabanic acid, oxalurea. Dialuric acid crystallizes in light yellow prisms, and is a monobasic acid. On mixing dialuric acid and a solution of alloxan, alloxantine is formed : C4H4N204 + C4H2N204 = C8H4N407 4 H20. Dialuric acid Alloxan The constitution of alloxantine is, therefore, rf./NH-CO\r-p/CO-NH\co CO\NH-CO/^\CO-NH/LU- 0 Alloxantine, on boiling with a solution of ammonium chloride, breaks into alloxan and dialuramide : C»H4N40, + NH4C1 = C4H2N204 4 C4H5N303 + HCl. Alloxantine Alloxan Dialuramide 168 URIC ACID AND ITS DERIVATIVES. Dialuramide, or uramile, is also formed by the reduction of nitro- or nitrosobarbituric acid, and has the constitution co<££:co>CHch"nh'cn- By the oxidation of dialuramide, murexide, the ammonium salt of pur- puric acid, is obtained. Purpuric acid stands to dialuramide in the same relation as alloxantine to dialuric acid. It is, therefore, alloxantinimide : 2 C4HsN:t03 4 0 = C,H,.Nr,06 + H20. Dialuramide Murexide C,H,N„0. = C,H*NsO, . NH3. Murexide Purpuric acid Murexide forms golden-greenish leaflets which are difficultly soluble in water, but which impart to it an intense purple color. It is soluble in potassa with an indigo-blue color which is destroyed on boiling, with the evolution of ammonia. Acids decompose it on boiling into alloxan and dialuramide. Murexide is used as a red dye for fabrics. On heating dialuric acid with glycerol, we obtain Hydurilic acid, CsHeN.Oe: 2 C4H4N204 = CeH6N403 4 H20 4 0, co<^:^>cH-CHco which crystallizes in small prisms containing 2 H20, and difficultly solu- ble in water and alcohol. From this is obtained Barbituric acid, C4H4N203, which crystallizes in large prisms. Bro- mine converts it into dibrombarbituric acid, C4H2Br2N203, fuming nitric acid into nitrobarbituric acid, or dilituric acid, C4H3(N02)N03. Ni- trous acid transforms it into nitrosobarbituric acid, or violuric acid, C4H3(NO)N203. Barbituric acid, CO<^tt-£q\CH2, *s malonylurea, and on boiling with dilute potassa falls into malonic acid and urea : PARABANIC ACID. 169 coch> + 2 h2o = co<£g: 4 CH Thus far we have considered 'NH"CO COOH CH2 . COOH Malonylurea, or barbituric acid, CO^^S-SqNcH,, Tartronylurea, or dialuric acid, Co/^g-S9\cH(OH), Mesoxylurea, or alloxan, C0^NH~CO^C0, , or CO<^ _ i . This body \NH-CH2 is obtained by the digestion of allantolne, C4H0N4O.j, a compound occur- ring in the urine of calves and of the foetal calf, with iodohydric acid : C4H„N403 4 2 HI = CH4N20 4 C3H4N202 -f I2. Allantolne Urea Hydantoine Allantolne is formed by the oxidation of uric acid in alkaline solu- tion, and also by heating glyoxylic acid (CHO-COOH) with urea. It crystallizes in glittering prisms, which are difficultly soluble in cold water and are decomposed by boiling with alkalis. 170 URIC ACID AND ITS DERIVATIVES. Hydantolne forms needles fusing at 206°. On boiling with baryta water they give Hydantoic acid, C3H6N03, or C02<^g-CH. "COOH' an acid crys" tallizing in large prisms. It can be produced by heating glycocoll with urea. We have thus three bodies which can be derived from each other by oxidation (or inversely by reduction): „ /NH"CO Glycolylurea, or hydantolne, CO^ _ i \NH CH2 /NH"CO Glyoxylurea, or allanturic acid, CO< i \NH"CH(OH) n /NH"CO Oxalylurea, or parabanic acid, CO< i J F \nh-co. To conclude, we shall take up several bodies and their decomposition-products, which occur in the animal organism. Xanthine, C5H4N"403, is a normal constituent of many animal tissues. It is an amorphous powder, very difficultly soluble in water. It combines with both acids and. bases. Sarcine, or Hypoxanthine, C5H4N40, occurs in the juice of the muscles, in the spleen, liver, kidneys, brain, etc. It is a crystalline powder, difficultly soluble in cold, water, more easily in hot. It possesses basic properties, and. decomposes at 150°. Its ammoniacal solution gives a precipitate with silver nitrate: C5H2Ag8N40 4-H20. The flesh of muscles contains, besides sarcine, Carnine, C7H8N403 4- H2O, which is a colorless powder, difficultly soluble in water. Nitric acid converts it into hy- poxanthine. If the above compounds are compared with uric acid, it will be noticed that they form a series, the members of which increase by an atom of oxygen. They are similar in their chemical relations, and probably have an analogous consti- tution. GUANINE. 171 Sarcine........C5H4N40 Xanthine......C5H4N408 Uric acid .....CsH4N403 Theobromine, C,H8N402, and Caffeine, C8HI0N4O3, are homologous with xanthine, and have a similar constitution. Theobromine exists in the cocoa-nuts. It is difficultly soluble in water, and forms crystalline salts with acids. Caffeine, The'ine,or Methyltheobromine, C8Hj 0N4O34-H2O, is contained in coffee and tea. It forms fine needles, which lose their water of crystallization at 120°, and fuse at 234°. They are diffi- cultly soluble in water, and sublime at a higher temperature unchanged. It possesses weak basic properties. When taken internally, it causes trembling and palpitation of the heart. Theobromine is dimethylxanthine,C7H„N402 = C5H2(CH3)2N402; and caffeine is trimethylxanthine, C8Hi0N4Oa = C5H(CH3)3N402. Their constitution is probably : NH-CH CH7N—CH CH7N—CH CO C-NH\ CO C"N-CHa CO C^'CH, I I >CO I I >CO I I >CO NH"C=N / KH"C=N CHrN ~C=N Xanthine Theobromine Caffeine Guanine, creatine, and creatinine are closely related to this group. Guanine, C5H5K50, we may imagine to be derived from xanthine by the replacement of an 0 by NH. It is converted into xanthine by the action of nitrous acid. It is the chief constituent of the excrement of spiders, and occurs in small amounts in guano. It is a white powder which unites both with acids and bases. It is decomposed by oxidation into guanidine, parabanic acid, and carbonic acid : C5H6N50 + 304- H20 = CH?N3 4- C3H2N203 4- C02. Guanidine Parabanic acid While the rest of urea, Co/jJjj-, is common to the group of sarcine, xanthine, and uric acid, the rest of the guanidine molecule, C(NH)<^NH-, 172 URIC ACID AND ITS DERIVATIVES. is characteristic of guanine. This rest, C(NH) CH3 CH3 5) CH3_CH2"C"CH3 CH,. We shall stop with hexane, as the number of isomers increases extraordinarily in the higher series, according to the law of permutations. Of heptane, C,H16, there are 9 isom- ers ; of octane, C8H18, 35 ;of nonane, C9H30, 155, etc. Only a few of these isomers are known, but new ones are being continually obtained. These hydrocarbons are formed by the decomposition of coal, the first member, methane, being contained in illumi- nating gas, while the others exist in petroleum. They can be produced artificially in the following manner : 1) By the dry distillation of a salt of a* monobasic acid of the next higher series with an alkali: CH3"COO]Sa 4- NaHO = CH4 + Na2C03 Sodium acetate C2H5"COONa 4- NaHO = C2H6 4- Na2C03. Sodium propionate 2) By the electrolysis of the corresponding monobasic acid : 2 CH3"COOH = CH3"CH3 + 2 C02 + H2. 3) By treatment of the zinc compound with water : (CH3)2Zn 4- 2 H20 = 2 CH4 4- Zn(OH)2. 176 RETROSPECT. 4) By treatment of the iodo-compound with sodium, a hydrocarbon of a higher series being formed : CH3I CH3 3 + Na2 == i 3 4- 2 Nal. CH3I 2 CH3 The lower members of this series, up to butane, are gaseous at ordinary temperatures. Pentane is a liquid boiling at a low temperature. The boiling points of the higher members, as for instance of those which are contained in petroleum, rise above 360°. The boiling points of the different isomers of a carbon series are, of course, different. The saturated hydrocarbons are characterized by the diffi- culty with which they are attacked by reagents, i.e., yield sub- stitution-products. Chlorine reacts with a few in the sun- light, but with the majority the reaction takes place only at a high temperature : 08H18 + C1, = C8H17C1 + H01. From their stability as regards substituting agents, these hydrocarbons are called paraffines (from para affinis, without affinity). Their general formula is CnH2n+ 2. Hydrocarbons (and all organic compounds) having a similar constitution, and which are derived from each other by the replacement of an H by a CH3, are called homologous. Thus all saturated hydro- carbons are homologous with methane, but pentane No. 3, and butane No. 1 are not homologous. Those hydrocarbons in which each carbon atom is bound with at most two other carbon atoms, so that each carbon atom consequently binds at least two hydrogen atoms, are called normal. In the series just given, the normal hydrocarbons are placed first. The general rule for the hydrocarbons of the series CMH2nf 2, is that each carbon atom is bound by only one bond to another carbon atom. UNSATURATED HYDROCARBONS. 177 Unsaturated Hydrocarbons. The carbon atoms of the unsaturated hydrocarbons are bound together by more than on'e bond. The simplest case is of two carbon atoms bound together each by two bonds, while the other carbons are bound as in the saturated hydrocar- bons. In this manner, compounds of the type C„H2„ are formed. C2H4 = CH2_CH2 C3H6 = 1) CH3 CH~CH2 C4H8 = 1) CH3_CH2-CH=CH2 2) CH3"CH=CH"CH3 3) CH3_C=CH2 CH3 C6H10=1) CH3"CH2"CH2"CH=CH2 2) CH3-CH2-CH=CH-CH3 . 3) CH3_CH=C"CH3 CH3 4) CH3_CH2-C=CH2 CH3 These hydrocarbons are formed by the decomposition of many organic compounds at a high temperature; by the action of dehydrating agents (cone. H2S04, P305, etc.) on mono- hydric alcohols ; and by treatment of their chlorides, bromides, or iodides, with potassium hydroxide : C3H,I + KOH = C3H6 4- KI 4- H20. The secondary and tertiary alcohols and their halogen de- rivatives break very easily into unsaturated hydrocarbons : CH3"CH2OH - H20 = CH2=CH2. Ethyl alcohol Ethylene The first members of this series, as ethylene, propylene, 12 Ethylene, Propylene, Butylene, Amylene, (Pentylene). 178 RETROSPECT. butylene, etc., are gaseous at ordinary temperatures. The higher ones are liquids or solids. They unite easily with the halogens : CH2=CH2 + Br2 = CH2Br"CH2Br, Ethylene bromide and with the halogen-hydric acids : CH2=CH2 4- HI = CH3_CH2I, Ethyl iodide also with sulphuric acid : CH2=CH3 4- H2S04 = CH3"CH2. HS04, Ethylsulphuric acid forming derivatives of the saturated hydrocarbons. The double binding is hence easily dissolved. They are also easily polymerized by substances having an attraction for water (sul- phuric acid, etc.). They are called olefines. There are, however, unsaturated hydrocarbons which con- tain carbon atoms fcound with more than two bonds, or in which there are more than two carbon atoms bound by two bonds. 1) C„H2„_2 series. C2H2 = CH=CH Acetylene, C3H4 = 1) CH=C-CH3 ) 2) CH2=CZCH0 ) Allylene, or propylene, C4H6 = 1) CH=C_CH2-CH3 2) CH3_C=C"CH3 3) CH2=C=CH-CH2 4) CH2=CH-CH=CHS C5H8, Pentylene, C6H10, Hexylene, etc. The hydrocarbons of the series, C„H2„_2, are formed by the action of alcoholic potassa on the compounds of the C„H2nBr2 series : CH2Br~CH2Br + 2 KHO = CH=CH 4- 2 KBr 4- 2 H20, or C2H4Br2 - 2 HBr = C2H2. - Crotonylene, or butylene, UNSATURATED HYDROCARBONS. 179 These hydrocarbons unite easily with two and four atoms of a halogen : C3H4 4- Cl2 = C2H4Cla C3H4 4- Cl4 = C3H4C14. 2) CBH2n_4 series. Only the higher members are known: C5H6, valylene, a large number of the compounds of the formula C10H16 (the terpenes), and the majority of the essential oils, of which the more important will be considered later on, belong to this series. It is easy to see that the number of isomers of the composition, Ct oHj 6, will be large. 3) CnH2n_6 series. The remarkably large number, and the great importance of the compounds of this particular class (the aromatic series), have led chemists from an early date to treat them as a separate class. We shall soon have an oppor- tunity of studying them. The hydrocarbons which contain still less hydrogen will also be taken up later on. The substances called petroleum and paraffine, which are met with in commerce, are mixtures of numerous hydrocarbons belonging to the CH2n + 2 and C„H2n series. As the hydrocarbons of the lower series (CH.,, C2H6, C2H4, etc.), are gaseous at ordinary temperature, while those of the higher series (C6H14, C6H12, C3H1C, etc.), are liquid, and the still more complicated ones (C20H42, etc.), are solid, the difference between petroleum and paraffine lies chiefly in the former consisting for the greater part of hydrocarbons under C20, while paraffine is composed chiefly of those from C20 to C27. Petroleum occurs in many places, but particularly in the United States. It is formed by the slow decomposition of organized bodies (plants and animals). Crude petroleum, as it issues from the earth, contains also the lower hydrocarbons, the greater part of which are evolved in a gaseous state, although a part of them remain in solution. On account of the gaseous and low boiling hydrocarbons which it contains, petroleum begins to boil at a low temperature, and as it ignites very easily, has given rise to many accidents. It has, therefore, to be rectified, i.e., distilled. The portions going over between 150° and 200° constitute the petroleum of commerce (kerosene). 180 RETROSPECT. The portion distilling under 150° is also utilized. That which goes over under 100° is known as petroleum-ether, cymogen, rigolene, etc., while that between 100° and 150° constitues the article known as benzine, or ligroine, which is used as a solvent for fats, resins, caoutchouc, etc., and for making gas. On account of its inflammability, it has to be handled with great care. Petroleum also contains paraffine, i.e., the liquid hydrocarbons hold solid ones in solution. Paraffine is also obtained by the dry distillation of wood, peat, and bituminous shales. It is a white, fatty substance resembling wax. It fuses at about 40° and boils over 300°. Halogen Derivatives of the Hydrocarbons. Both the saturated and unsaturated hydrocarbons yield sub- stitution-derivatives in which one or more atoms of hydrogen are replaced by chlorine, bromine, or iodine. The number of isomeric derivatives is greater than the number of the hydrocarbons. Ethane, C2H6, for instance, yields two isomeric dichlor-derivatives, CH2Ci~CH2Cl, ethylene chlo- ride, and CH3"CHC12, ethylidene chloride. Butane, C3H8, or CH3~CH2~CH3, yields two monochlor-derivatives, CH3-CH2_CH2C1 and CH3"CHCrCH3. The monochlorides, bromides, and iodides are generally made from the monohydric alcohols, either by digesting with gaseous chlorhydric acid, or by treating them with phos- phorus chloride, bromide, or iodide : C2Hs(OH) + HCl = C2H5C1 + H20, 3 C2H5(OH) 4- PBr3 = 3 C2H5Br + PH303. They are also formed by the action of chlorine and bromine on the saturated hydrocarbons, and by the addition of the halogen-hydric acids to the unsaturated hydrocarbons. In the latter case the halogen unites with the carbon atom which holds the least hydrogen : HALOGEN DERIVATIVES. 181 CH3-CH=CH3 + HI = CH3-CHrCH3 CH3-C=CH2 + HI = CH3"CrCH3 CH3 CH3 The dichlorides, dibromides, and di-iodides are produced by leading chlorine, bromine, or iodine, into either the hydro- carbons of the series C„H2„, in which case the two halogens take up with two different carbon atoms ; or into the mono- chlorides, bromides, or iodides, in which case both the halo- gens unite with the same carbon atom : CH2=CH2 4- Cl8 = CH2C1"CH2C1 CH3CH2C1 + Cl2 = CH3~CHC12 4- HCl. The other chlorides, etc., are formed by the continued action of chlorine, etc., on the alkylogens. On treatment with moist silver oxide, the halogens are replaced by hydroxyl, forming alcohols, glycols, aldehydes, etc.: 2 CH3"CH2C14- Ag20 4- H20 = 2 CH3"CH2(OH) + 2 AgCl CH2CrCH2Cl 4- Ag20 4- H20 = CH2(OH)_CH2(OH) 4- 2 AgCl CH3"CHC12 4-Ag20 = CH3"CHO + 2 AgCl. On digestion with a silver salt, an ester (compound ether) is obtained : C2H5C1 4- C2H302Ag = C2H5-C2H302 + AgCl. Acetic ester C2H4C12 + 2 C2H302Ag = C2H4=(C2H3C2)2 4- AgCl. On digestion with potassium salts, the halogen is replaced by the rest in combination with potassium : C2H5C1 + KCN = C2H5"CN C2H5C1 + KSCN = C2H5_SCN, etc. 182 RETROSPECT. Nascent hydrogen converts the halogen derivatives back into the hydrocarbons.* Hydroxyl Derivatives. 1) Alcohols. a) Monohydric alcohols, C„H2n + 1OH : CH40 = CH3OH Methyl alcohol, B.p. 65° C2H60 = CH3"CH2OH Ethyl alcohol, B. p. 79° ( CH3"CH2"CH2OH Propyl alcohol, B. p. 97° C3H80= •! CH3_CH(OH)-CH3 Isopropyl alcohol, ( B. p. 83° f CH3"CH2_CH2-CH2(OH) Butyl alcohol, B. p. 117° CH3_CH2-CH(OH)-CH3 hoi, CH3-CH_CH2(OH) C4H10O-( CH, Secondary butyl alco- B. p. 980° Isobutyl-alcohol, B. p. 108° Trimethyl-carbinol, B. p. 82c CH3-C(OH)~CH3 CH3 C CH3_CH2-CH2-CH2-CH2(OH) Normal amyl al- cohol, B. p. 137° CH3-CH2-CH2_CH(OH)-CH3 Propyl-methyl- carbinol, B. p. 119° (C2He)-CH(OH)-C2H6 Di-ethyl-carbinol, B. p. 117° C6H120 <( CH3-CH_CH2-CH2(OH) Ordinary amyl alcohol, CH3 B. p. 130° CH3~OH(OH)-CH-CH3 Isopropyl-methyl-carbi- CH3 nol, B. p. 108° CH3-CH2"C(OH)-CH3 Ethyl-dimethyl-carbinol, CH, B. p. 97° *The action of iodohydric acid is both substituting and reducing. Glycerol and HI yield isopropyl iodide : HYDROXYL DERIVATIVES. 183 C6H140H« + H,0 Ethyl alcohol Sulphuric acid Ethyl sulphuric acid C6H6 4- SO,^g| = SO.^gj*1' 4- H20 Benzene Sulphuric acid Benzene sulphonic acid 2 O.H.OH + SO^gg = SO,<^gg«g« + 2 H20 Ethyl sulphuric ester NITRO COMPOUNDS.—SULPHONIC ACIDS. 199 2 C6H6 4- S02/gg = SO/gogs + 2 H20 g Sulphobenzide C2H5OH 4- N02OH = N02-0~C2H5 4- H20 Ethyl nitric ester C6H6 + N02OH = N02"C6H5 4- H20. Nitrobenzene The difference between the nitro- and sulphonic acid compounds, and the nitrous and sulphurous esters isomeric with them, appears plainly in the products which are formed by their reduction with nascent hydrogen. N"CH3 isomeric with 0=N-CTCH3. Both are CH3N02. /^%s Methyl nitrous q q ester Nitromethane HO-S-CH3 isomeric with CH3"0_S-H. Both are CH4S03. A A Methylsulphonic acid Methyl sulphurous ester When the nitrogen and sulphur are bound directly to carbon, as is the case with the nitro- and sulphonic acid compounds, these elements re- main bound to the carbon on reduction, and the oxygen which was in combination with them is replaced by hydrogen : N_CH3 gives H2N"CH3 + 2 H20, Methylamine A HO-S-CH3 gives HS-CH3 + 3 H20 ; Methyl mer- captan. D C< /H \C1 H\l J, L /H Cl/( CI H \C1 Benzene hexachloride * The term " benzine" is now used to designate the distillates of petroleum going over between 70°-100°, and which consist of a mixture of hydrocarbons of the C„H2n+2, and CnH2a series, principally of C„HI4, CeHi2, C7H18, C7H14, etc. 204 AROMATIC COMPOUNDS. former case, chlorine tri-iodide is formed, which causes the substitution; in the latter case the molybdenum chloride gives up a part of its chlorine to the benzene, and is regenerated by the chlorine, which is being continually introduced. The first substitution product is Monochlorbenzene, CCH5C1. This product is obtained when the action of the chlorine has not been of too great duration. Chlorbenzene can also be obtained by the action of phos- phorus chloride on the hydroxyl-derivative of benzene (phenol): 3 C6H5(OH) + PC13 = 3 C6H5C14- P(OH)3. It is a colorless liquid boiling at 132°. Like most of the chlorides of the aromatic compounds, it differs from the chlo- rides of the fatty compounds in its chlorine being very strongly bound, and hence not easily substituted. Neither alcoholic potassa, silver salts, nor ammonia react with it. Nascent hydrogen converts it back into benzene. A mixture of chlor- benzene and methyl iodide, treated with sodium, yields methyl- benzene : C6H6C1 4- CH3I 4- Na2 = C6H6"CH3 + NaCl + Nal. In the same manner chlorbenzene when digested with sodium gives diphenyl: * C6H5C1 4- C6HSC1 + Na2 = C6H5"C6H5 + 2 NaCl. We shall meet this reaction frequently. Diphenyl, C6H5"C6H5, or C12H,„, crystallizes in colorless leaflets fus- ing at 70° and distilling at 254°. Like benzene, it is the starting-out point for a vast number of derivatives. Dichlorbenzene, C6H4C12. All three are known. Two of them, the para-compound (1. 4) principally, and the ortho- The benzene rest, C6H6~, is called phenyl. CHLOR- AND BROMBENZENES. 205 compound in lesser amounts, are formed by the continued action of chlorine on benzene in the presence of iodine. o C6H4CL boils at 179°; m C6H4C12 boils at 172°; p C6H4C12 is solid, and fuses at 54° and boils at 173°. Trichlorbenzene, C6H3C13, is also known in all three mod- ifications. The orthopara (1.2.4) is formed by the continued action of chlorine on benzene. It fuses at 17° and boils at 213°. The second, metameta (1.3. 5), is obtained by the decomposition of trichloraniline. It fuses at 63° and boils at 208°. The third, orthometa (1.2. 3), fuses at 53°, and boils at 218°. Tetrachlorbenzene, C6H2C14, is known in its three modifi- cations. 1) (1. 2. 4 . 5) is produced by the action of chlorine on benzene. Crys- tals fusing at 138° and boiling at 246°. 2) (1.2.4.6) needles fusing at 51° and boiling at 246°. 3) (1.2.3.4) crystals fusing at 46° and boiling at 254°. Pentachlorbenzene, C6HC1S. Needles fusing at 85° and boiling at 270°. Per chlorbenzene, C6C16, is the final product of the action of chlorine on benzene. It fuses at 226° and boils at 332°. Monobrombenzene, C6H5Br, is formed when bromine is al- lowed to act on benzene for some time (14 days). It is a liquid boiling at 154°. At a higher temperature substitution-products richer in bromine are formed. Most of them are solid. All three of the dibrombenzenes, C6H4Br2, are known. Two of them (1. 2, b. p. 224°, and 1. 3, b. p. 219°), are liquids. The third (1.4) is solid, fusing at 89° and boiling at 219°. Tribrombenzenes, C6H3Br3. 1) 1. 2 .4 fuses at 44° and boils at 276°. 2) 1. 2 . 3 fuses at 87°. 3) 1.3.5 fuses at 119° and boils at 278°. Tetrabrombenzenes, C;H2Br4. 1)1.2.3.5 fuses at 99°. 2) 1. 2. 4. 5 fuses at 140c. 206 AROMATIC COMPOUNDS. Pentabrombenzene, CcHBr5, fuses above 240°. Hexabrombenzene, C6Br6, fuses above 300°. Mono-iodobenzene, C6H5I, and substitution-products richer in iodine are formed when iodine is allowed to act on benzene in the presence of iodicacid. C6H5I isliquid (b. p. 185°). The others are solid. Chlorbrombenzenes, C0H4ClBr, etc., are also known. Nitrobenzene, C6Hs"N02. If benzene is added to fuming nitric acid as long as it dissolves, and the solution then poured into water, nitrobenzene is precipitated in the form of a heavy, light-yellow oil. It has a pleasant odor, resembling that of bitter almonds. It boils at 205°, and is insoluble in v/ater and soluble in alcohol and ether. It is used in perfumery under the name of "oil of mirbane," and also for the pro- duction of aniline. Reducing agents convert the nitro-group into the amido- group. Nitrobenzene is thereby converted into amidobenzene, or aniline. C6H5~N02 + 3 II2 = C6H5"NH2 + 2 H20. Dinitrobenzene, C6H4(N02)2, is formed, when benzene is added to a mixture of nitric and sulphuric acids. The ortho-compound fuses at 118°, the meta- at 90% and the para- at 172°. Reducing agents convert it first into nitro-amidobenzene, or nitraniline, C6H4(N02)NH2, and then into the di-amido- benzene, C6H4(NH2)2. Substitution products which contain chlorine, bromine, and the nitro- group are also known. Benzenesulphonic acid, C 6 H 5 SO 3 H, is produced by digesting benzene with concentrated sulphuric acid: C?H6 + H2S04 - C6H5"S03H 4- H20. PHENOL. 207 It forms deliquescent crystals containing l-2- molecules of water. It is a monobasic acid, and forms crystalline salts with bases. Nitric acid nitrates it. Phosphorus pentachlorido converts it into benzenesulphochloride, C6H5~S03C1, which, by the ac- tion of ammonia, is converted into benzenesulphamide, CGH5"S03(NH2), (f. p. 153°), by the action of zinc dust, into zinc benzenesulphinate, Zn(C0H5~SO2)2, and by zinc and HCl into C6H5~SH, phenolsulphydrate, corrresponding to the mercaptan of the fatty series. As we have already seen (p. 199), the sulphur in sulphonic acids is bound directly to the carbon. Hence the reduction takes place in a man- ner analogous to that of the nitro-compounds : C0H5_NO2 is reduced to C(;H5"NH2 CoHrSO.H " " CoHrSH On heating benzene with fuming sulphuric acid, there is formed, Benzene-disulphonic Acid, C6I14(S03II)2. It is a dibasic acid. The three modifications are known. Benzenetrisulphonic acid has also been obtained. By heating benzene with sulphuric anhydride, we obtain Sulphobenzide, Diphenylsulphone, C6H5"S02"C6H5, which fuses at 128°. It is no longer an acid, as both of the hydrox- yls of the sulphuric acid are replaced by the group C6H5. Phenol, Carbolic Acid, Hydroxylbcnzene, C6H5~OH. Phenol is the chief constituent of heavy coal-tar, and is produced on a large scale. It crystallizes in long colorless needles fusing at 42° and boiling at 182°. It possesses an unpleasant and cling- ing odor, and a burning caustic taste. Its sp. gr. is 1.065. On exposure to the air it gradually turns red. A small amount of water prevents it from crystallizing. It is soluble in 15 parts of water. It is very poisonous, coagulates albumen, and produces blisters on the skin. Solutions of ferric salts are 208 AROMATIC COMPOUNDS. colored intensely violet by it. A slip of pine-wood moistened with chlorhydric acid, and then dipped in phenol and exposed to the sunlight, becomes blue. Bromine produces, even in dilute solutions, a white precipitate of tribromphenol. It is used in medicine, and as a disinfecting and antiseptic agent, and also in the production of numerous colors. The hydroxyl-derivatives of the benzene series are called phenols, as they differ considerably from the alcohols of the fat series, although they are really a class of tertiary alcohols. They possess quite strong acid properties, and unite easily with metals to form species of salts. Phenol dissolves in sodium hydroxide solution, forming sodium phenoxide or phenylate, C6H5ONa. It dissolves lead oxide, producing lead phenoxide, (C6H50)2Pb. If CI, Br, I, or N02, ispresent besides the OH, the resulting compounds have completely acid properties and act as true acids. By treating phenols with phosphorus chloride, or bromide, the OH is replaced by CI, Br, etc. They are not oxidized to aldehydes, ketones, or acids, since outside of the OH there is no hydrogen united to the carbon atom (tertiary alcohols). They unite with acid rests, forming compounds which corre- spond to the esters. On heating with zinc dust, the phenols are converted back into hydrocarbons by inverse substitution: CGH5OH 4- Zn = C6H6 + ZnO. Phenol can be produced from benzene in two ways. 1) By converting the benzene into benzenesulphonic acid, C6H5_S03H, and fusing this with potassium hydroxide : C6HrS03H + 2 KOH = C6H5(OH) + K2S03 -f H20. 2) By converting the benzene into nitrobenzene, reducing this to amido- benzene, CBH5"NH2, and the amidobenzene into the so-called diazoben- zene, which is decomposed by water into phenol. The hydrogen atoms of phenol can be substituted in the same manner as those of benzene. PICRIC ACID. 209 There are obtained by the action of chlorine : Monochlorphenol, CCH4C10H (1. 2. b. p. 176° ; 1. 3, b. p. 214°; 1. 4, b. p. 217°). Dichlorphenol, C,iH3Cl2OH (1. 2 . 4, f. p. 43°, b. p. 214°). Trichlorphenol, C6H2C130H (f. p. 68°, b. p. 244°). By leading chlorine through phenol in the presence of iodine, i.e. by the action of iodine chloride, we obtain perchlorphenol, C8C150H, fusing at 187°. Bromine and iodine act in a similar manner. By the action of nitric acid, nitro-derivatives are obtained from phenol up to the third substitution : C6H4(N02)OH, Mononitrophenol, all three modifications are known. C6H3(N02)2OH, Dinitrophenol, four modifications are known. C6H2(N02)3OH, Trinitrophenol, two modifications are known. Nitrophenols, C6H4(N02)OH. 1. 2, yellow prisms fusing at 45° and boiling at 214°. 1. 3, colorless crystals fusing at 96°. 1. 4, colorless needles fusing at 115°. Dinitrophenols, Cr,H3(N02)2OH : a, leaflets fusing at 114°; /3, needles fusing at 64° ; y, bright yellow needles fusing at 104°; 8, colorless prisms fusing at 141°. Trinitrophenol, Picric Acid, C6H2(N02)3OH. (1.2.4. 6).* Picric acid is formed by the action of nitric acid on various organic compounds (indigo, Peruvian balsam, silk, wool, etc.), most easily, however, from phenol. It crystallizes in light yellow, glittering, odorless leaflets, which taste intensely bit- ter. They are soluble in water, fuse at 122°, and explode on rapid heating. Weak reducing agents (ammonium sulphide) convert it into dinitroamidophenol, or picramic acid, stronger * Substitution-derivatives of benzene and its analogues are termed symmetrical when the intervals between the substituting elements or groups are equal. The following derivatives are symmetrical: 1. 4 ; 1.3. 5; 2.4.6, etc. 14 210 AROMATIC COMPOUNDS. reducing agents (tin and chlorhydric acid), into triamidophe- nol, or pier amine. Potassium picrate, C6H2(N02)3OK, crystallizes in yellow needles, which explode violently by heating or percussion. Picric acid is used as a yellow dye for silk and wool. When heated with potassium cyanide, picric acid gives a deep violet-red liquid, which contains the potassium salt of isopurpuric acid, CsHsNsOo: C.H4(N04)sOH 4 3 KCN -f 3H20 = C\H4KN606 -f C02 + NH3 -f 2 KHO. Picric acid Potassium isopurpurate Isopicric acid, C6H2(N02)30H, (1. 3 . 4. 5) is formed by the action of fuming nitric acid on m-nitrophenol. Bright yellow prisms fusing at 170°. There are also derivatives of phenol which contain chlorine, bromine, or iodine and the nitro-group, e. g., Monochlornitrophenol, C6H3C1(N02)(0H). Phenolmethyl Ether, Aniso'll, C6Hs~0~CH3, is formed by the action of methyl iodide on potassium phenoxide : C6H5OK + CH3I = C6H50"CH3 4- KI, or by the distillation of potassium phenoxide with potassium methylsulphate : C6H5OK + CH3"KS04 = C6HsO"CH3 -f K2S04. Both of the reactions are analogous to those of the formation of the ethers of the fat-compounds. It is a colorless liquid with a pleasant odor, boiling at 152°, and insoluble in water. The benzene nucleus is chlorinated, etc., by the action of chlorine, bromine, or iodine. Nitric acid nitrates it. Mono-, di-, and tribromanisoil, and mono-, di-, and trinitroanisoi'l are known. Phenylethyl Ether, Pheneto'll, C6H5~0~C2H5,is produced in an analogous manner. It boils at 172°. Phenyl Ether, C6Hs"0~C6H5, is formed by the dry dis- PHENYL MERCAPTAN. 211 tillation of copper benzoate. It is a solid mass with a pleas- ant odor, fusing at 28° and boiling at 246°. Phenol-sulphonic Acid, C6H4(OH)S03H, is formed in two modifications (1. 2 and 1. 4) by mixing phenol with concen- trated sulphuric acid. Both are monobasic acids and yield finely crystallizable salts. One of the principal salts is the zinc phenolsulphonate : (C.H»S04).Zn 4- 7 H20, which is obtained by dissolving zinc oxide in the acid. It crystallizes in colorless, rhombic columns, easily soluble in water and alcohol. It is used as a caustic and disinfectant. If phenol is heated with fuming sulphuric acid, phenol- disulphonic acid, C6H3(OH)(S03H)2, is produced. It is a dibasic acid. If the action takes place under pressure, phenol-trisulphonic acid, C6H2(OH)(S03H)3, is obtained. It is a tribasic acid. By digesting phenol with phosphorus pentasulphide, we obtain Phenylsulphydrate, Phenyl Mercaptan, C6H5"SH : 5 C6H5"OH + P2S5 = 5 C6H5"SH 4- P205. It is a colorless oil with a repulsive odor, boiling at 166°, and insoluble in water. It can also be obtained by the reduc- tion of benzenesulphonic acid. The oxygen of the air oxi- dizes it into phenyl disulphide, (C6HS)2S2. 2 C6H5(SH) + 0 = (C6H5)2S2 4- H20. Phenylsulphide, (CCH5)2S, is also known. The analogous bodies of the fat-series have already been mentioned : Ethyl mercaptan, C2H5~SH, Ethyl sulphide, C2HrS-C2Hs, Ethyl disulphide, CaH5"S"S~CsH„ Phenyl sulphydrate, Cr,H5~SH Phenyl sulphide, CnH.rS-C0H5, Phenyl disulphide, C,H4-S-S-C.H». (See p. 102.) 212 AROMATIC COMPOUNDS. All three of the hydroxyl derivatives of benzene are known. They are called catechol, resorcinol and quinol. Catechol, Pyrocatechin, C6H4(OH)2 (ortho-compound), is produced by heating catechu rapidly. It forms quadratic columns fusing at 104°, and boiling at 245°. Ferric chloride colors its aqueous solution green. A monomethyl-ether of catechol, guaiacol, C6H4(OH)(OCH3), is formed by the dry distillation of guaiacum resin, and exists in beech-wood tar. It is a colorless liquid boiling at 200°. Resorcinol, Resorcin, C6H4(OH)2 (meta-compound), is ob- tained by fusing galbanum-resin with potassium hydroxide. It crystallizes in tablets fusing at 118° and boiling at 276.5°. On exposure to the air it turns red. Ferric chloride solution colors it deep-violet. Eesorcinol yields a trinitro-derivative, which stands in the same relation to resorcinol as picric acid to phenol. Trinitroresorcinol, Styphnic Acid, C6H(N02)3(OH)2. It is produced by the nitrition of resorcinol, and also by the action of cold nitric acid on numerous resins (galbanum, gum- ammoniac, etc.). It crystallizes in yellow prisms fusing at 176° and exploding by rapid heating. It is difficultly soluble in water, and behaves like a strong dibasic acid. It is used as a yellow dye. Quinol, Hydroquinone, C6H4(OH)2 (para-compound). It is made by leading sulphurous acid through quinone, C6H402 : C6H402 4- H2 = C6H602 = C6H4(OH)2. Rhombic columns soluble in water. It fuses at 169° and sublimes by careful heating. It is converted into quinone by the oxygen of the air and by all oxidizing agents. Quinone, C0H4O2. The two following formulas have been proposed for quinone : QUINONE. 213 /CH=CH\ ^CH"CHv C=0 0=C and Cf-0---0-%C. \CH=CH/ \CH=CH/ In the former case they would be double ketones. Quinone is formed by the oxidation of quinol and all bodies which contain quinol. It is made by the oxidation of aniline with chromic acid. It forms golden-yellow crystals fusing at 116°, and possessing a piercing odor which irri- tates the eyes, and causes weeping. It is slightly soluble in cold water, easily in hot, and is volatile with steam. It is poisonous, and colors the skin brown. Oxidizing agents de- compose it entirely forming oxalic acid. Reducing agents convert it into quinol. Chlorine converts it into chlorinated quinones. The following are known : Monochlorquinone, C6H3C102, Dichlorquinone, C6H2C1202, Trichlorquinone, C6HC1302, Tetrachlorquinone, CfiCl402. Tetrachlorquinone, or Chloranile, C6C1402, is formed by the action of KC103, on various aromatic compounds. It is usually made from phenol. It forms yellow scales soluble in water, difficultly soluble in alcohol, and which fuse at a high temperature. Sulphurous acid converts all chlorinated qui- nones into chlorinated quinols. Two atoms of chlorine in chloranile can be replaced by hydroxyls and amido-groups. Chloranilic acid, Cf,Cl2(OH)202, or C6H2C1204, is formed when chlor- anile is warmed with potassa. C0C1402 + 2 KOH = CcCl2(OH)202 4 2 KC1. It forms red crystals, and is dibasic. Chloranilamide, C6C12(NH2),0, or Cr,H4Cl2N202, is formed by the action of alcoholic ammonia on chloranile : C6C1402 + 4NH3 = C6C12(NH2),02 4 2 NH4C1. 214 AROMATIC COMPOUNDS. Reddish-brown needles which yield ammonia and chloranilic acid when treated with potassa. Bromine substitutions of quinone have also been obtained. They resemble the chlorinated quinones. Quinone unites with quinol to form an intermediate product known as green hydroquinone or quinhydrol : C6H402 4- C6H602 It forms glittering needles which can be converted into either quinone or quinol. Only two of the three possible trihydroxyl derivatives of benzene are known, viz., pyrogallic acid and phloroglucinol. Pyrogallic Acid, or Pyrogallol, C6H3(OH)3, or C6H603, (1.2. 4), is formed by heating gallic acid : C6H2(OH)3"COOH = C6H3(OH)3 4- C02. It forms white, glittering leaflets with a bitter taste, fusing at 115°. Although it unites with metals to form a species of salts, it has no true acid properties. It is a trihydric ter- tiary alcohol. Water dissolves it easily. Its aqueous solution absorbs oxygen from the air with avidity, especially when an alkali is present. It acts, therefore, strongly reducing. The final products which are formed from it by the assumptiou of oxygen, are oxalic and acetic acids. It colors ferrous salts dark blue, and ferric salts red. On heating with zinc dust it is converted into benzene : C6H3(OH)3 4- 3 Zn = C6H6 + 3 ZnO. A solution of pyrogallol containing potassium hydroxide is used in gas analysis to remove oxygen from mixtures of gases (eudiometric analy- sis). Pyrogallol is also used in photography. Phloroglucinol, or Phlorglucin, C6H3(OH)3, or C6H603, is obtained by the decomposition of complicated bodies. It forms large, colorless crystals with a sweet taste, which con- tain two molecules of water. It fuses at 220° and reduces ANILINE. 215 alkaline cupric solutions like dextrose. A bromine and nitro- derivative of it are known. There are no further hydroxyl substitutions of benzene known. Among the amido-derivatives of benzene, amidobenzene is the most important, partly because an enormous number of compounds are derived from it, and partly because it serves as the starting-out point for the production of a series of dyes which are commercially very important. Amidobenzene, Aniline, C6H5~NH2, or C6H,N. Like all amido-derivatives of the aromatic series, aniline is formed by the reduction of a corresponding nitro-compound. The re- ducing agents which are generally used for the reduction of nitro-compounds, and nitro-benzene in particular, are : 1). Alcoholic ammonium sulphide, in which the hydrogen sul- phide is the reducing agent, and sulphur is set free. 2). Zinc and chlorhydric acid. 3). Tin and chlorhydric acid. 4). Iron filings and acetic acid. 5). And, finally, zinc dust and water. The last four act by setting free hydrogen. Aniline is formed also by the dry distillation of many aro- matic compounds (indigo) and also by the ignition of bones and coal (it exists in coal tar). Aniline is made commercially by the reduction of nitrobenzene with iron filings and acetic acid, or zinc dust and water : C6H5"N02 + 3 H2 = C6H5"NH2 + 2 H20. Aniline cannot be obtained by the digestion of chlorbenzene with alco- holic ammonia, as ethylamine is formed from ethyl chloride. Aniline is a light-yellow, strongly refractive liquid with a peculiar odor. It is somewhat heavier than water (sp. gr. 1.02) and boils at 185°. On long standing it becomes colored brown by the action of the air and light. The minutest trace of aniline can be detected by the deep violet color which is produced when it is brought into contact 216 AROMATIC COMPOUNDS. with calcium hypochlorite (chloride of lime). The color passes quickly into a dirty red. The aniline colors will be mentioned later on. Aniline has basic properties and unites with acids to form salts, of which the hydrochloride, oxalate and nitrate are the most important, e.g., C6H5"NH2.HC1. It unites also with many salts to form peculiar double compounds, viz.: ZnCl2.2C6H,N. Aniline yields three kinds of derivatives depending on whether the substitution takes place in the hydrogen of the benzene nucleus, the hydrogen of the amido-group, or in both. Chlorine, bromine and iodine form chlor-, brom-, and iodo- anilines, concentrated sulphuric acid gives a sulphonic acid, and nitric acid a nitro-derivative. All of these substitutions take place in the benzene nucleus. The chlorine, etc., derivatives of the fatty compounds pro- duce derivatives of aniline in which the substitution occurs in the amido-group. If aniline is digested with methyl iodide, ethyl iodide, etc., we obtain methylaniline, dimethylaniline, ethylaniline, di- ethylaniline (secondary and tertiary anilines). C6H5"NH2 + CH3I = C6H5'NH(CH3).HI. C6H5-NH(CH3) + CH3I = C6H5-N(CH3)2.HI. The ammonium compounds are also known, viz.: C6H6-N(CH3)3I and C6H5-N(CH3)3OH. As the alcohols react on aniline hydrochloride at an elevated tempera- ture, they may be used instead of the iodides to produce the methylated, etc., anilines. C6HrNH2. HCl + CH3OH = C6H5NH(CH3). HCl + H20 CaH6_NH2. HCl -f 2 CH3OH = C6HaN(CH3)2. HCl 4- 2 H20. SUBSTITUTED ANILINES. 217 The anilines in which one or both of the amido-hydrogen atoms are replaced by hydrocarbon rests, are liquids resembling aniline, and, as they possess basic properties, form crystalline salts with acids. If the secondary and tertiary anilines are heated for some time in closed vessels at 300°, they are converted into primary bases by atomic migration, the methyl of the amido-group ex- changing with a hydrogen atom of the benzene nucleus : C6H5NHCH3 gives C6H4(CH3)NH2 Methylaniline Toluidine CeH5N(CH3)2 gives C6H3(CH3)2NH2. Dimethy laniline Xylidine In this manner all the hydrogen atoms in aniline have been succes- sively replaced by hydrocarbon rests. In the same manner that both H's of the amido-group of aniline can be successively replaced by mono-valent hydrocarbon rests, the substitu- tions can be effected by di-valent hydrocarbon rests. In this case, how- ever, the di valent rest may replace one H in two molecules of the amide, or two H's in one molecule. fnfi§5-Snl>C2H4 or ^-f^-nV Bthylenediphenyldiamine, (C6H5 JNM)/ CH2 NH C6H5 (C„H5)2) jx or CH2-N(CfiH5)-CH2 enyldiamine, and (C2H4)2P2 CH2-N(C„H3)-CH2 ' PIT \ Cr,H5-N=(C2H4) or i 2 \n~C6H5 Ethylenephenylamine. CH2/ In the first case two H's in two aniline molecules are replaced by one ethylene, in the second case, four H's in two aniline molecules are re- placed by two ethylenes, in the third case, two H's in one molecule of aniline are replaced by one ethylene. They are all formed by the action of ethylene bromide on aniline. The group CH3_CH=, ethylidene, which is isomeric with ethylene CH2=CH2, can also be introduced into aniline, producing : ( C2H4[N2 or CH3-CH/^I^g65 Ethylidenediphenyldiamine. H2 ) 218 AROMATIC COMPOUNDS. Slllt^ or CH3-CH<£g£)>CH-CH3 Di-ethylidene-diphenyldiamine. They are formed by the action of aldehyde on aniline. The isomerism between these two series is clearly shown by the constitutional formulas. In the ethylene compound, both of the two carbon atoms of the ethylene are united to N, while in the other series, only one carbon atom is in combination with the N. Tri-valent hydrocarbon rests can also be introduced into aniline, as for instance, CH=, which may be introduced into aniline by the action of chloroform. We have, for example : PH 1 (C6H5)2 [ N2 or CH^j^j?!^ Methenyldiphenyldiamine, also CHI (C6H6)2 t N2 or CH3_c/^H(i6^^5 Ethenyldiphenyldiamine, etc. As these bodies contain one or more aniline rests, they are capable of combining with one or more molecules of acid to form salts. The amido-hydrogen of aniline can also be substituted by acid rests forming bodies called anilides. Formanilide, C6H5~NH(CHO). CHO is the mono-valent rest of formic acid. The compound is produced by heating aniline oxalate : (C6H5NH2)2C2H204 = C6H5NH(CHO) + C6H5NH2 +C02 4- H20. Acetanilide, CGH5~NH(C2H30), is formed by the action of acetyl chloride on aniline, or by boiling aniline with glacial acetic acid, or acetic anhydride. It fuses at 112° and boils at 295°. The substitution of an acid rest may also be effected by the di-valent acid rest of a di-basic acid, e.g. the rest of the hypo- thetical carbonic acid, C0^OH by the rest C(K SULPOCARBANILIDE. 219 P6tt5t^tt/CO Carbanilide 6 M /CO Carbanilamide. Both of the compounds are ureas in which one or two H's are replaced by the benzene rest. We have already seen (p. 51) that one or more hydrogen atoms in urea may be replaced by hydrocarbon rests : C0/^g°3H5 Ethylurea CO Oarbanilic acid. OH We shall have occasion to study many other anilides. They are all formed either by heating the corresponding aniline salt, or by elimination of the elements of water, or hydrogen sulphide : C6H5NH2.C2H40 = C6H5NH"(C2H30) + H20. Aniline acetate Acetanilide The anilides are converted back into the aniline salts by taking up the elements of water. Several of them are produced by particular methods which will be mentioned when we come to consider the compounds individually. C H -NH\ Carbanilide (Diphenylurea), c^'NH/^0' ^' p' 235°)> C TT -NTT\ and Carbanilamide (Monophenylurea), 6 5-^H ">CO, (f. p. 144°), are formed when aniline is heated with urea : O.H.NH, + fll)CO = C»\^>CO + NH3, or when potassium cyanate is boiled with aniline sulphate : CARBANILIDE. !421 2 KC0N4- (C6H5-NH2)2"H2S04 = 2 Co/™"C6Hs + KS04. 2 KCON 4- 2 [(C6H5-NH2)2-H2SOJ = 2 CO Diphenylguanidine. If, however, sulphocarbanilide is digested with aniline (substituted ammonia) and litharge, the sulphur is replaced by the di-valent-group, C6H5N: cIHsNH/^06115)' Triphenylguanidine. 222 AROMATIC COMPOUNDS. Sulphocarbanile, Phenyl-mustard-oil, C6H6"N=CS, is a colorless liquid with an odor resembling that of mustard-oil. It boils at 222°, and its reactions are analogous to those of the other mustard-oils. In the same manner, anilides have been obtained containing the rests of oxalic, succinic, malic, tartaric, and other acids. The amido-hydrogen of aniline can also be replaced by the benzene rest. Thus by heating aniline with aniline hydro- chloride, we obtain : C6H6v C6H5—)N Diphenylamine, H/ which fuses at 54° and boils at 310°. It possesses basic prop- erties, and unites with acids to form salts. The triphenyla- mine (C6H5)3N, fusing at 127°, is also known. The hydrogen of the benzene nucleus in aniline can, of course, be easily substituted by any element, or atomic-group, which substitutes the hydrogen of benzene. A number of isomers are met with here, depending on whether the substi- tuting atom, or group, is separated from the NH2-group by one or two hydrogen atoms. There are known, for instance, chlor-, brom-, iodo-, and nitranilines, aniline-sulphonic acid, di- and trichlor-, brom-, etc., anilines. Most of them exist in numerous modifications. The amido-hydrogen of the substituted anilides can also be substituted, viz., chloracetanilide, etc. If two hydrogen atoms of benzene be substituted by amido-groups, three isomeric compounds are formed. They are called Di-amidobenzenes, or Phenylenediamine, C6H4(NH2)2. They are all known. They possess basic properties, and unite with two molecules of a monobasic acid, or one molecule of a AZ0-C0MP0UNDS. 223 dibasic acid, to form salts. As in aniline, both the amido- hydrogen and the hydrogen of benzene-nucleus may be sub- stituted. a) 1 . 2, fuses at 102° and boils at 252°; /?) 1.3, fuses at 63° and boils at 287° ;y) 1.4, fuses at 147° and boils at 267°. The ortho-diamido derivatives of the hydrocarbons, on heating with organic acids, eliminate water, forming amidines, while with aldehydes they yield aldehydines, viz. : C6H4(NH2)2 + CH3"COOH = C6H4<^JH^C-CH3, Ethylenephenyl- enamidine. C6H4(NH2)2 4- 2 CH3-CHO = CeRi<(^yCR-CR3)i,Phenylenaldehydine. Triamidobenzene, C6H3(NH2)3, is obtained by the reduction of dinitran- iline. It fuses at 103° and boils at 33°. Between nitrobenzene and amidobenzene, stands a series of bodies which are formed either by the partial reduction of nitrobenzene or by the oxidation of amidobenzene. Starting out from nitrobenzene we have Nitrobenzene, C6HSNQ2 C6H5N02 ( C H _N\ \ 6 5 1 >0 Azoxybenzene, (c6h5-n/ h (C6H5"N A z < n Azobenzene, (CCH5"N (C6H5"NH (C6H5"NH CgHg^NHj C6H5-NH2 Hydr'azobenzene, A m idobenzene, A niline, These intermediate compounds are called Azo-compounds.* * Nitrogen was called azote by Lavoisier. From this word, the prefix "azo" is derived. 224 AROMATIC COMPOUNDS. The azo-compounds contain two benzene rests united to a pair of linked nitrogen atoms. C6H ~N\ Azoxybcnzene, _■ \0, or C12H10N2O, is formed by C6H5 N/ boiling nitrobenzene with alcoholic potassa. It crystallizes in yellow, glittering needles, fusing at 36°. Nitric acid converts it into nitro-compounds, which by reduction yield azobenzene and hydrazobenzene. Azobenzene, C6H5"N=N~C6H5, orC12H10N2, is produced by the distillation of nitrobenzene with alcoholic potassa. It crystallizes in large yellowish leaflets, fusing at 66°. With nitric acid it forms nitro-derivatives. Hydrazobenzene, C6H5"NH"NH"C6H5, or C12H12N2, is formed by the action of ammonium sulphide on azobenzene. It crystallizes in colorless tablets fusing at 131°. Oxidizing agents convert it back into azobenzene, reducing agents trans- form it into aniline. Acids convert it at once into an isomeric compound, benzidi ne, i6 4 2, which is also obtained from C6H4-NH2' dinitrodiphenyl, i6 4 2, by reduction with ammonium 1 y C6H4"N02' J sulphide. It crystallizes in glittering, silvery leaflets, which fuse at 118°, and have strong basic properties. There is a large class of bodies whose constitution is simi- lar to that of azobenzene, and in which the benzene rest, C6H5, is united to a pair of doubly-bound nitrogen atoms, C6II5~N-N~. They are called diazo-compounds. Azobenzene may be considered as a particular case in this class of com- pounds, in which the free bond of the nitrogen is satisfied by a benzene rest. If nitrous acid is passed into an alcoholic solution of aniline, diazobenzene-anilide, or diazo-amido-benzene, CfiHrN=N-NH-CnHK, DIAZ0-C0MP0UNDS. 225 is formed at first. By continued action, or by the use of aniline nitrate, diazobenzene nitrate is produced : C6H5N=N-N03, 2 C6H5NH2 -f- HN02 = C6H5-N=N"NHC6H5 + 2 H20 C6HSNH2 . HN03 + HN02 = C6H5-N=N_N03 + 2 H20. We see, therefore, that by the action of nitrous acid both of the atoms of amido-hydrogen in aniline are replaced by an atom of nitrogen, the third bond of which remains free. The substituted anilines, such as chloraniline, etc., also form diazo-compounds with nitrous acid. The diazo-compounds are unstable, exploding violently on heating, or by percussion. On heating with water, nitrogen is eliminated and a phenol is produced : C6H5N2"N03 + H20 = C6H5OH + N2 + HNOs. On boiling with absolute alcohol, both of the nitrogen atoms are replaced by hydrogen : C6H5N,-X03+C.,H5OH = C6H64-N., 4-CoH40 " + HN03, Or by boiling with chlor-, brom-, or iodohydric acids, both of the hydrogen atoms are replaced by an atom of chlorine, bro- mine, or iodine : CGH5N2_N03 + HCl = C6H5C1 + HNOs + N2. By means of the diazo-compounds, therefore, the nitro-group can easily be replaced by hydroxyl, chlorine, bromine, etc. The conversion of aniline (and all aromatic amides) into diazo- compounds, and the easy decomposition of the latter, attended by evolu- tion of nitrogen, is a phenomenon which we have already seen to be characteristic of ammonia. In the case of ammonia, however, both of these reactions take place at once. Ammonium nitrite (i.e., ammonia-(- nitrous acid) breaks on heating into nitrogen and water : NH3 -f- HN02 = N2 + 2 H20. Compare also the action of nitrous acid on amines (p. 46). 226 AROMATIC COMPOUNDS. If diazobenzene nitrate is heated with hydrogen potassium sulphite, a compound, C6H5N2H3S03K, is obtained, in which the group S03K can be replaced by H. The resulting body is the first member of a series of compounds having the constitution, C6H5~NH~NH2, and which are derivatives of the unknown compound, NH2~NH2. They possess strong basic properties, and unite directly with acids. They are called hydrazine compounds (compare p. 46). Certain derivatives of diazobenzene have of late become very important as dyes. Diazo-amidobenzene, CgHs-N=N~NH~C6H5, in the presence of alcohol and an aniline salt, passes after a time into the isomeric amido- azobenzene: Cf,H5-N=N-C6H5(NH2), or aniline-yellow. By the action of nitrous acid on meta-di-amidobenzene, diazo-di-amido-azobenzene : (NH2)CJirN=N-NH-C6H4(NH2), which is formed, passes into the isomeric triamido-azobenzene: (NH2)C6H4-N=N_C6H3(NH2)2, or Bismarck-brown. The compound intermediate between aniline-yellow and Bismarck-brown, is called chrysoidine. It is an orange dye. Its salts form superb crystals, having a beetle-green, metallic sheen. It is made by the action of diazobenzene chloride on metadiamidobenzene : C,H»-N=N-C1 4 C.H4(NH8), = C0H5-N=N-C6H3(NH2).i 4 HCl. In a similar manner, a multitude of new colors have been produced by allowing negative derivatives of diazobenzene to react on primary and secondary monamines, phenols, and phenol-sulphonic acids. Diazosulph- anilic acid and dimethylaniline yield an orange dye : (HS03)CcH4-N=N-C6H4-N(CH3)2. Diazocumene chloride and /J-naphthol-disulphonic acid give a scarlet: CfiH2(CH3)3-N=N-C10H4(OH)(HSO3)2. These colors are remarkable for their brilliancy and fastness, as well as for their great tinctorial powers. A more complicated class of compounds, having greater tinctorial BENZONITRILE. 227 powers than the preceding, is obtained by diazotizing the amido-group of amido-azobenzene, and carrying out, with the substance thus produced, reactions similar to those just mentioned : C6HrN=N-C6H4(NH2)+ HN02 + HC1 Amido-azobenzene = c6h5-n=n-c6h4-n=n-ci 4 2 H20, Diazoazo-benzene chloride Prom the chloride and /2-naphthol-disulphonic acid, the scarlet, C6HrN=N-C6H4-N=N-C1„H4(0H)(HS03)2, is obtained. In the same manner that the amido-derivatives are produced from nitrated benzenes by reduction, the nitrated phenols can be converted into the corresponding amido-compounds. Mononitrophenol, C6H4(N02)OH, into Amidophenol, C6H4(NH2)OH, Dinitrophenol, C6H3(N02)2OH, into Amidonitrophenol, CGH3(N02)(NH2)OH, and Diamidophenol, C6H3(NH2)2OH, Trinitrophenol, C6H2(N02)3OH, into Dinitroamidophenol, C6H2(N02)2(NH2)OH, Triamidophenol, C6H2(NH2)3OH. Corresponding to the two cyanides which exist in the fat- series, and which depend on the existence of the two isomeric cyan-groups, ~C=N and ~N=C, there are two cyan-derivatives of benzene, cyanbenzene, or benzonitrile, C6H5~CN, and isocyanbenzene, C6H5~NC. Cyanbenzene is produced by the distillation of benzamide (see p. 242) with phosphoric anhy- dride, and is hence called benzonitrile: C6H5-CO_NH2 = C6H5_CN + H20. It is also formed by heating benzoic acid with potassium sulphocyanate: 1) CBH5-COOH + KSCN = CfiH.rCOOK 4- HSCN, Benzoic acid Potassium Potassium Sulphocyanic sulphocyanate benzoate acid 2) C6HrCOOH 4- HSCN = C6H5-CN + H„S -f- C02. Benzonitrile 228 AROMATIC COMPOUNDS. On heating with alkalis, it takes up the elements of water, and is converted into carboxylbenzene (benzoic acid) and ammonia : C6H5_CN 4- 2 H20 = C6H5"COOH 4- NH3. It is a colorless liquid with the odor of bitter almonds, boil- ing at 191. Nitric acid nitrates it. Isocyanbenzene, C6H5~NC, is obtained by digesting aniline with chloroform and potassium hydroxide : C6H5"NH2 + CHC13 + KOH = C6H5-NC + KC14- H20 + 2 HCL The action of the potassa is only to accelerate the reaction. Acids decompose it into aniline and formic acid with the addi- tion of the elements of water ; CgH5"NC -f 2 H,0 = C6H5"NH2 4- CH202. It is a colorless liquid with a highly offensive odor, boiling at 160° with partial decomposition. (Compare p. 106.) By the action of PCi5 on benzene at a high temperature, HCl is elimv nated, and the compound, C6H5~PC12, phosphenyl chloride, is formed. II is oxidized by water to phenyl-hypo-phosphorous acid, C6H5P(OH)2. It unites directly with chlorine to form phosphenyl-telrachloride, CoH5~PCl4, which is decomposed by a small amount of water into phenyl-oxychloride, C6H5~P0C12, and by an excess of water into phenylphosphinic acid C6H6~PO(OH2). Phenylphosphinic acid corresponds to methylphosphinic, acid (p. 68), and phosphenyl chloride to methylphosphine, except that the hydrogen of the latter is replaced by chlorine. Phenylphospldne, C6H5~PH2, is obtained by the action of iodohydric acid gas on phosphenyl chloride. Among the metallo-derivatives of benzene, mercury-phenyl, Hg( C 6 H 5) 2, is worthy of notice. It is produced by the action of sodium amalgam on brombenzene. It fuses at 120°, and its mercury atom is easily replaced by other groups. TOLUENE. 229 Toluene. So far, we have considered only those derivatives of benzene in which the hydrogen of the benzene nucleus has been replaced by halogens, or by atomic groups containing oxygen, sulphur, or nitrogen. We come finally to a kind of substitution of benzene by which series of aromatic compounds are built up in the same manner as in the fatty series, viz., by the substitution of the hydrogen of the benzene by hydrocarbon-rests, as methyl, or mono-valent derivatives of methane. Let us take up the first two cases, viz., C6H5~CH3, and CGH5~C2H5. The two great divisions of organic bodies, the fatty and the aromatic compounds, are both represented at the same time in these substances. The derivatives which are formed by the substitution of hydrogen in the benzene nucleus possess all the characteristics of the aromatic compounds, and are, in fact, true homologues of the corresponding benzene derivatives. On the other hand, the derivatives which are formed by the substitution of the hydrogen of the methyl, or ethyl, possess all the characteristic properties of the fatty compounds, and are only aromatic compounds in so far that they contain the benzene rest with its easily substitutive hydrogen atoms. By the action of chlorine on methylben- zene, a monochlorinated substitution-product is formed, in which the chlorine enters into the benzene nucleus, C6H4C1~CH3, (we shall not take into account the three possible isomeric modifications of this compound). Such a chlorine derivative has all the characteristic properties of an iiromatic compound; the chlorine is hardly capable cf direct replacement; neither potassium hydroxide nor silver oxide transpose it into hydroxyl; nor does ammonia replace it with the amido-group. On the other hand, the compound, C6H5~CH2C1, has also the properties of a chloride of the fatty series. The chlorine is directly replaced with ease, for 230 AROMATIC COMPOUNDS. instance by hydroxyl, when potassium hydroxide, or silver oxide, acts on it, or by the amido-group when treated with ammonia. If an atom of hydrogen in the benzene nucleus is replaced by hydroxyl, a phenol, CGH4(OH)~CH3, is pro- duced, while, if the replacement takes place in the methyl- group, an alcohol is formed, C6H5~CH2(OH). The benzene rest, is called the nucleus, and the methyl-group, the side-chain. Benzene-derivatives which contain side-chains, are, there- fore, divided into two sharply separated groups, viz., those in which the hydrogen of the benzene nucleus has been substituted, and those in which the hydrogen of the side-chain has been substituted. By the substitution of hydrogen rests for the hydrogen of the benzene nucleus, the following compounds are obtained : Methylbenzene, C6H5"CH3 = C7H8 j Dimethylbenzene, (3 isomers) C6H4(CH3)2 i _ q jj (Ethylbenzene, C6H5"C2H5 J" 8 10 {Trimethylbenzene, (3 isomers) C6H3(CH3)3>j Methylethylbenzene, (3 isomers) C6H4 ] q j| Y = ^9^12 Propylbenzene,* (2 isomers) C6H5"C3H,J f Tetramethylbenzene, (3 isomers) C6H2(CH3)4 ' Dimethylethylbenzene, (3 isomers) C6H3(C2H5)(CH3)2 -j Di-ethylbenzene, (3 isomers) C6H4(C2H6)2 j-=C10H14 Methylpropylbenzene, (6 isomers) C6H4(CH3)(C3H,) Butylbenzene,f (4 isomers) C6H5"C4H9 *CflH5"CH2"CH2"CH3, and CeH5~CH/^, propylbenzene and iso- >pylbenzene. fl) C0HrCH2-CH2-CH2-CH3 3) C6HrCH<^g* /PIT 2) CcHrCH2-CH<^gg^ 4) CeH5-C^CH3 TOLUENE. 231 There is only one hydrocarbon of the formula C,H8. But of the formula C8H10 there are four; of C9H12, eight; and of C10H14, nineteen. The number of isomers increases very rapidly with the rising content of carbon. The number of cases of isomerism is also very great when the hydrogen of a highly constituted hydrocarbon is substituted by chlorine, hydroxyl, etc. But relatively few of the vast number of compounds which we see in perspective are known, and this is particularly the case in the higher series. Methylbenzene, Toluene, Toluol, C6H5~CH3, or C,H8. Toluene with other methylated benzenes, as dimethyl-and tri- methylbenzene, is formed, together with benzene, by exposing many organic compounds to a very high temperature. These methylated benzenes arc separated from benzene and from each other by fractional distillation. In its physical properties, toluene resembles benzene com- pletely. It is a colorless oil with nearly the same odor as benzene. It boils at 111°, but does not become solid under 0°. It can be made from benzene artificially, by digesting a mix- ture of monobrombenzene and methyl iodide with sodium : CGH5Br + CH3I + Na2 = C6H5-CH3 4- NaBr + Nal. This reaction is adapted to the production of any higher aromatic hydrocarbon from benzene. To produce ethylben- zene, ethyl iodide is used, and so on. Toluene can also be converted into monobromtoluene, which with methyl iodide yields dimethylbenzene. The methyl-group of toluene is converted by oxidizing agents into carboxyl, COOH. This is the case not only when the group is methyl, but also when it is a methyl derivative of higher carbon content. Methylbenzene, C6H6"CH3, and ethyl- benzene, C6H5~C2H5, both yield the same carboxylbenzene, C6H5~COOH (benzoic acid). The oxidation of aromatic hydrocarbons affords, therefore, a reliable method of deter- 232 AROMATIC COMPOUNDS. mining how many atoms of hydrogen in benzene are substituted by hydrocarbon rests. If C8H10, for instance, yields CcH5COOII on oxidation, it must be ethylbenzene, while if CcH4(COOH)2 h formed, it is proved to be dimethylbenzcnc. When chlorine acts on toluene in the cold, the hydrogen of the benzene nucleus is substituted (C6H4C1~CH3), but if the action takes place in heated toluene, the hydrogen of the side- chain is substituted, C6H5~CH2C1. The following chlorine derivatives of toluene are known : CKH.C1 CH- Monoch lortoluene C6H3C12' Dichlortoluene •CH, C0H2C13 CH3 Trichlortoluene CgHCl4 CH3 Tetrachlortoluene CgCl5 CH3 Pentachlortoluene CCII5_CH2C1 Benzyl chloride C6H2C13 CH2C1 Trichlorbenzyl chloride CgHg CHC12 Benzyl dichloride C0H2C13"CHC12 Trichlorbenzyl dichloride C 6 H g C CI 3 Phenylchloroform C?H4CrCH2Cl Chlorbenzyl chloride C6HC14_CH2C1 Tetrachlorbenzyl chloride C6H4CrCHCl2 Monochlorbenzyl dichloride CgHCl4_CHCl2 Tetrachlorbenzyl dichloride ccH4crcci3 Monoclilorphenylchloroform C?H3C12"CH2C1 Dichlorbenzyl chloride C6C15"CH2C1 Pentachlorbenzyl chloride "CHC12 Dichlorbenzyl dichloride C6C15~CHC12 Pent.iclilorbenz) 1 dichloride Cg.ti.jd2 CCl., Dichlorphenylchloroform CBH3C1C C6H2C13"CC13 Trichlorphenylchloroform CBHC14"CC13 Tetrachlorphenylchloroform Almost every one of these compounds exists in several iso- meric modifications, e.g., there are three isomeric monochlor- tolucnes. We see hence that the number of isomeric derivatives is enormous. If chlorine is led into cooled toluene, chlorinated derivatives are obtained in which the hydrogen of the benzene nucleus is replaced. But if the toluene is boiling, the hydrogen of the methyl-group is substituted, and the substitution thus takes place in the side-chain. The extent of substi- tution (mono-, di-, tri-chlortoluene, etc.), depends on the duration of the action. If, however, chlorine is passed through toluene which contains iodine, so that it is really exposed to the action of IC1:), the substitution takes place in the benzene nucleus, even when boiling. BENZYL CHLORIDES. 2h"3 1. a). Monochlortoluene, CCH4C1 CH3. All three isomers are known. The ortho- and meta-compounds boil at 156°, the para at 160°. 1. b). Benzyl Chloride, CCHS~CH2C1, is formed by lead- ing chlorine through boiling toluene, or by the action of HCl on benzyl alcohol, C6H5"CH2OH. It is a colorless liquid boiling at 176°. On oxidation it passes into benzoic acid, C6H5"COOH (p. 239). If a mixture of benzyl chloride and benzene is warmed with aluminum chloride, HCl is evolved and benzylbenzene, or diphenylmethane, C6H5"CH2"CgH5, is obtained. It forms needles fusing at 26° and boiling at 261°. On oxidation it is converted into benzophenone, CgH5~CO"~C6H5. This reaction is applicable to all chlorides of the fatty compounds and those chlorides of the aromatic compounds in which the chlorine is in the side-chain. If a chloride of this kind is mixed with an aromatic hydro- carbon and treated with aluminum chloride, chlorhydric acid is elimin- ated, and a compound of the two organic bodies is formed, although the aluminum chloride does not take part in the reaction. Methyl chloride and benzene with the addition of aluminum chloride, give toluene and also dimethylbenzene, trimethylbenzene, etc. CH.C1 + Cf,H6 = CH3"C6H5 4- HCl ; 2 CH.C1 -f C6H6 = C.H4(CH,)a 4 2 HCl, etc. Chlorine gives under the same conditions with benzene, triphenylme- thane, C6H3(CH3)3. Acetyl chloride gives with benzene, acetophenone, (methylphenylketone), C6H5~CO~CH3. 2. a). Dichlortoluene, C6H3C12"CH3, is formed by leading chlorine into toluene containing iodine. It boils at 196°, and on treatment with oxidizing agents is converted into dichlordracylic acid, C6H3Cl2"COOH. 2. b). Monochlorbenzyl chloride, CoH.CrCH.Cl, is obtained by leading chlorine into benzyl chloride containing iodine, or by the action of chlo- rine on boiling toluene. It boils at 214°. On oxidation it is converted into chlordracylic acid. 2. c). Benzol chloride, C0H5-CHC12, is produced either by the action of chlorine on boiling toluene, or phosphorus pentachloride on benzyl al- dehyde (bitter almond-oil), C.HrCHO. It boils at 207°, and by oxida- tion is converted into benzoic acid, C6,H,~COOH. 234 AROMATIC COMPOUNDS. 3. a). Trichlortoluene, C6H2C13~CH3, is formed by leading chlorine into toluene containing iodine. It boils at 235°, and is converted by ox- idation into trichlordracylic acid, C6H2Cl3~COOH. 3. b\ Dichlorbenzyl chloride, C6H3C12~CHC12, is obtained by leading chlorine into benzyl chloride containing iodine, or by leading chlorine into boiling dichlortoluene. It boils at 241°, and on oxidation passes into dichlordracylic acid, C6H3Cl2~COOH. We shall not proceed farther with the description of the chlorinated toluenes, as we have now learned the methods by which all the remaining derivatives can be produced. According to the duration of the action of chlorine on boiling toluene, we obtain, C6H5_CH2C1, CCH5-CHC12, or C6H«"CC13. If a chlorin- ated toluene is employed instead of toluene, further chlorinated deriva- tives are produced. If monochlortoluene, C6H4C1~CH3, is used we ob- tain, C6H4CrCH2Cl, C6H4CrCHCl2, and C6H4CrCCl3 ; dichlortoluene, C6H3CirCH3, yields C„H3C12-CH2C1, C6H3CirCHCl2, C6H3C12-CC13, etc. The chlorine can hence be introduced into the side-chain at will. The chlorine can be introduced into the benzene nucleus with the same ease by either cooling the toluene, or adding iodine. In this way we can obtain from toluene : C.H4CrCH,; C0H3C12_CH3; C.HaCl,"CH, etc. From benzyl chloride, CBH5~CH2C1, we have : C0H4CrCH2Cl; C6H3C12-CH2C1 ; C.HsCirCH9Cl, etc. From benzal chloride, C6H5"CHC12, C„H4CrCHCl2 ; C0H3C12-CHC12; C.HsCirCHCla, etc. Bromine and iodine act similarly to chlorine. As the nu- merous bromine and iodine derivatives resemble the chlorine compounds, we shall omit them. The nitro-derivatives are, however, worthy of attention. According to the theory, three mononitrotoluenes are possible. All three are known. Two of them are formed by the action of nitric acid on toluene. One of them is a liquid (liquid nitrotoluene), and has the constitution, CCH4 -j g CH2. It boils at 223°, and is completely destroyed by boiling with chromic acid solution. Boiling dilute nitric acid, however, NITR0T0LUENES. 235 converts it into orthonitrobenzoic acid, C6H4 •] ~ pioArp The other is solid at ordinary temperatures, fuses at 54° and boils at 236°. It has the constitution, C6H4 -j . nrr2, and yields on oxidation nitrodracylic acid C6H4 -j . pi^AxT. The third nitrotoluene is not obtained directly by the action of nitric acid on toluene, but by an indirect method from nitroamidotoluene. (By conversion into the diazo-compound and then into the nitrotoluene). It is liquid at ordinary tem- peratures, solidifies when cooled, and fuses then at 16°. It boils at 231°, and has the constitution, C6H4 -j o nu2- On oxidation it yields nitrobenzoic acid, C6H4 •] o poOH" The fourth nitro-derivative of toluene, in which the nitro-group is in the side-chain, C6H5-CH2-N02, has not yet been obtained. All four hydroxyl-derivatives of toluene have been pro- duced. Those which contain the OH in the benzene nucleus are called cresols. When it is in the side chain, they are known as benzyl alcohols. Benzyl alcohol is a true primary alcohol, and yields benzyl- aldehyde and benzylic or benzoic acid on oxidation : C6H4 | gg Cresol. C6H5 CH2OH Benzyl alcohol (like CH3CH2OH) C6H5CHO Benzaldehyde (like CH3CHO) C6HgCOOH Benzoic acid (like CH3COOH). The cresols are phenols. Two of them, the ortho- and paracresol, occur in coal-tar. The properties of all three of them resemble those of phenol. Orthocresol fuses at 31° and boils at 185° ; metacresol is liquid and boils at 201° ; para- cresol fuses at 36° and boils at 199°. By the action of oxidiz- 236 AROMATIC COMPOUNDS. ing agents on them, or rather on their methyl ethers, or acetic esters, the CH3 is converted into carboxyl, while the hydroxyl remains unchanged. A body is thus obtained of the com- position C6H4 -j nrvnrp These compounds have the same relation to the phenols as the glycollic acids to the alcohols, and are at once both phenols and acids. They are called hydroxybenzoic acids. Benzyl Alcohol, C6H5"CH2(OH), or C7H80, is formed from benzyl chloride (which is produced by leading chlorine into boiling toluene) by digesting with potassium hydroxide : C6H5~CH2C1 + KOH = C6H5-CH2(OH) 4- KOI, and by the reduction of benzyl aldehyde : C6H5_CHO 4- H2 = C6H5_CH2OH, or by boiling benzaldehyde with alcoholic potassa: 2 C6H5_CHO + KHO = CgH5_COOK + C6H5-CH2OH. Potassium benzoate All of these methods of formation show very distinctly the constitu- tion of benzyl alcohol. Chlortoluene does not yield a cresol on diges- tion with potassium hydroxide, because the chlorine which is in the benzene nucleus is not easily substituted. On the other hand, benzyl chloride acts like a chloride of the fatty series. The conversion of benz- aldehyde into benzyl alcohol by reduction is exactly analogous to the general property of the reduction of aldehydes to alcohols mentioned on page 85. Benzyl alcohol is a colorless liquid with an aromatic odor, boiling at 207°, and insoluble in water. It is oxidized by nitric acid into benzaldehyde (bitter almond-oil). Boric an- hydride converts it into benzyl ether : 2 o,h,-oh,oh = 0;!;-gg;>o + h8o. By treating benzyl alcohol with gaseous chlorhydric acid, it is converted into benzyl chloride, C6H5~CH2C1. BENZALDEHYDE. 237 The principal esters of benzyl alcohol are : Benzyl Acetic Ester, C6H5"CH2"0"C2H30, (b. p. 210°). Benzyl Benzoic Ester, C6H5"CH2"0"C7H50. Benzyl Cinnamic Ester, CgH5"CH2"O"C0H,O (see later). Benzyl-benzoic ester and benzyl-cinnamic ester occur in balsams of Peru and Tolu. (OTT Besides the three cresols, C6H4 -j ^.tt , and benzyl alcohol, C0H5~CH2OH, we have already met another body of the formula, C7H„0, viz.: anisoil, C6HrO"CH3, the methyl ether of phenol (p. 210). Benzaldehyde, Bitter Almond-Oil, C6H5~CHO, or C,H60. Bitter almond-oil does not occur in the free state in nature, but is formed by a peculiar fermentation of a glucoside, amyg- dalin, existing in bitter almonds, by which it breaks into dex- trose, cyanhydric acid and benzaldehyde : C20H27NO11 + 2H20 = 2 C6H120g 4- CNH + C7H60. Bitter almond-oil is obtained by distilling bitter almonds with water. It distils over with cyanhydric acid and steam, and separates as a heavy oil in the distillate. It is also formed by the decomposition of benzr! chloride with sulphuric acid, and further by heating benzyl chloride with lead nitrate. It is a colorless, strongly refractive liquid with the odor of bitter almonds. It has a burning taste, boils at 180°, and is difficultly soluble in water. It is not poisonous, although the crude bitter almond-oil, on account of its containing cyan- hydric acid, is poisonous. Benzaldehyde has all the charac- teristic properties of an aldehyde; it unites with acid alkali sulphites to form crystalline compounds ; oxidizing agents convert it into benzoic acid; hydrogen sulphide converts it into benzsulphaldehyde, C6H5"CHS. Phosphorus penta- chloride transforms it into benzal chloride, C6HS~CHC12, i.e., its oxygen is replaced by 2 CI. It is nitrated by fuming nitric acid, forming nitrobenzaldehyde, C6H4(N02)~CHO. 238 AROMATIC COMPOUNDS. When mixed with potassium cyanide and allowed to stand some time, it is converted into a polymeric body, benzoin, C14H1202 = 2C,H60, which crystallizes in colorless, odor- less prisms insoluble in water, from which chlorine abstracts two H's, forming benzil, C1 iH1002. Benzil is converted back into benzoin by the action of hydrogen. Alcoholic potassa changes it into benzilic acid, C14H1203 : 014H100,4-KOH = 014H11K08. Potassium benzilate The constitution of these bodies is probably : C6H5-CO_CH(OH)-C6Hs C6HrCO-CO-C8H6 Benzoin Benzil (C6H5)2=C(OHfC02H. Benzilic acid Benzaldehyde is converted into its pinacone (p. 113), by reduction with sodium amalgam, or zinc and chlorhydric acid, the formula of this body is : C14H1402 = CoH5~CH(OH)-CH(OH)-C„H5, hydrobenzoln. It forms tablets fusing at 134°. On oxidation, it is converted into benzoin and benzil, and finally into benzoic acid. Like all pinacones, hydrobenzoin splits out water easily and passes into the pinacoline, C14Hi20 (f. p. 131°). On the other hand, benzoin forms by reduction with zinc and chlorhydric acid a compound, Ci4H120, desoxybenzoln (phenylbenzylketone) • C6H5-CO-CH2-C6H5. There is also formed by the reduction of benzaldehyde an isomeric compound, Ci4Hi402, isohydrobenzoln, which also splits out water easily and is converted into Ci4Hi20, (f. p. 102°). Benzaldehyde is converted by the action of ammonia into hydrobenza- mide, C2iHi8N2, which forms octahedrons fusing at 110°. This body, on boiling with alkalis, falls into isomeric and strongly basic amarine (prisms fusing at 100°), and by distillation, into another isomeric compound, lophine, C2iHieN2, which forms needles fusing at 270°. Benzaldehyde also unites with cyanhydric acid forming the nitrile of phenylglycollie acid, C6H5~CH(OH)-CN, which with ammonia yields easily the nitrile of phenylamidoacetic acid, CCH5-CH(NH2)~CN. The nitriles are easily converted into phenylglycollie acid: C6HrCH(OH)-COOH, BENZOIC ACID. 239 and phenylamidoacetic acid, C6H5"CH(NH2)COOH, by boiling with chlor- hydric acid. Sodium eliminates the oxygen from benzaldehyde, and the two rests free from oxygen unite, forming stilbene : C14H12 = C6H5-CH=CH-C6H5, which is a molecule of ethylene in which two H's are replaced by two benzene rests (diphenylethylene). The same compound is obtained by the distillation of benzyl sulphide, (C6H5CH2)2S. It crystallizes in thin, colorless leaflets fusing at 120°. Benzoic Acid, Phenylformic Acid,G6H5~COOH, or C,H602. Benzoic acid is the first aromatic carboxylic acid that we have met. We have seen that the phenols* exhibit acid properties when containing nitro-groups, but we shall meet with a large number of true carboxylic acids among the aromatic com- pounds. These acids behave in the same manner as the acids of the fatty series. The hydrogen of the carboxyl is easily replaceable by metals. An aromatic acid, therefore, which contains one carboxyl- group as a side-chain is monobasic. When two carboxyls are present, it is dibasic, etc. The hydroxyl of the carboxyl of the aromatic carboxylic acids can be replaced by chlorine, bromine, or iodine (aci- chlorides) by ammonia (amides) and by acid rests (anhy- drides). By distillation with a formate, they can be converted into their aldehydes, and with the salt of another organic acid, into the corresponding ketones. As they are aromatic acids, chlorine, bromine, iodine, the nitro-group, and the amido-group can be easily introduced into the benzene nu- cleus, yielding an immense number of derivatives, many of which are, of course, isomeric. * The H of the EC~OH group, in a tertiary alcohol resembles somewhat the H of the carboxyl group, 0=C"OH, in being replaceable by metals. i The phenols are tertiary alcohols. 240 AROMATIC COMPOUNDS. Benzoic acid occurs in gum-benzoin and other gums. It is formed by the oxidation of toluene and benzaldehyde, and also by the simultaneous action of carbonic acid and sodium on brombenzene : C6H5Br 4- Na8 4- C02 = C6Hs_COONa 4- NaBr. It is usually made by heating gum-benzoin, which sublimes the benzoic acid, or by the decomposition of hippuric acid (see later), which occurs in the urine of herbivora, by boiling with chlorhydric acid, which de- composes the hippuric acid into glycocoll and benzoic acid, or finally by heating phenylchloroform, C6H5"CC13, with water. Benzoic acid forms thin, colorless, glittering leaflets with a weak aromatic odor, which fuse at 120° and boil at 249°, although it sublimes under 100°. It is difficultly soluble in cold water, more easily in hot, and very soluble in alcohol and ether. It is a monobasic acid, and forms salts with bases, which are mostly easily soluble in water. If a benzoate is submitted to dry distillation with an excess of alkali, benzene and a car- bonate are formed. This reaction is analogous to the forma- tion of methane from acetic acid (p. 15) : CH3"COONa + NaHO = CH4 + Na2C03 Sodium acetate Methane C6H5"COONa + NaHO = C6H6 4- Na2C03. Sodium benzoate Benzene If, however, a benzoate is submitted to dry distillation by itself, a ketone, benzophenone, CgH5"CO"C6H5, is produced, in the same manner that acetone is obtained from an acetate : CH3COONa CHs\pft,m rA CH3COONa = CH3/00 + Na*C03- Acetone £•§■3™*' = ?'5'>0 + Na!COs. C6H5 COONa C6H5/ Benzophenone BENZOYL CHLORIDE. 241 The aromatic ketones are also formed when an acid and a hydrocarbon, both of which belong to the aromatic series, are heated with phosphoric anhydride, which acts as a de- hydrating agent: C6H5COOH + C6H6 = C6H5-CO-C6H5 4 H20. Benzoic acid Benzene Benzophenone Benzophenone, C13H10O, crystallizes in prisms fusing at 49° and boiling at 295°. Fuming nitric acid converts it into dinitrobenzophenone ; nascent hydrogen into benzhydrol: o:I:>oh(oh>> (as acetone is converted into isopropyl alcohol). Benzhydrol is a secondary alcohol containing two benzene rests together with the group CH(OH) (just as isopropyl alcohol contains two methyl groups). By the dry distillation of a mixture of a benzoate and a salt of another organic acid, mixed ketones are obtained, e. g., from an acetate and a benzoate we get methylphenylketone, CH \ or acetophenone, p A yCO, etc. Sodium amalgam converts this compound into the secondary alcohol, C6H5-CH(OH)-CH3. By treating benzoic acid with phosphorus pentachloride, we obtain Benzoyl Cliloride, C6H5C0C1, which corresponds to acetyl chloride CH3"COCl (p. 93). C6H5COOH + PC15 = C6H5C0C14- HCl + POCl3. It is a colorless liquid with a pungent odor which causes violent weeping. It boils at 199°. It decomposes gradually with water into benzoic and chlorhydric acids : C6H5C0C1 + H20 = C6H6COOH 4- HCl. 16 242 AROMATIC COMPOUNDS. The chlorine of benzoyl chloride is easily replaced by other atoms, or groups. With potassium bromide it yields benzoyl bromide, C6H5~COBr; with potassium iodide, benzoyl iodide, C6H5~COI; with potassium cyan- ide, benzoyl cyanide, CGH5~COCN; with phosphorus pentachloride at a high temperature (200°), its oxygen is replaced by two chlorine atoms, forming benzotrichloride: c6h5-coci 4- PC15 = c6h5-cci3 4 POCl3. Benzoyl chloride forms with sodium benzoate Benzoic Anhydride, rj6H5~CO/^ : C6H5C0C14- CgH5_COONa = NaCl + c6H5"c(x)a Benzoic anhydride forms colorless, prismatic crystals, fusing at 42° and boiling at 350°, insoluble in water, and easily solu- ble in alcohol and ether. If, instead of sodium benzoate, benzoyl chloride is mixed with the sodium salt of another acid, mixed anhydrides are obtained. Sodium acetate for instance, gives C TT —PO\ Benzoylacetic Anhydride, q^-qqyO: C6H6-C0C14- CH3-COONa = NaCl 4- ch36-CO^°- Benzoyl reacts with ammonia, forming Benzamide: C6H5-C0C1 4- NH3 = C6H5-CONH2 + HCl. Benzamide crystallizes in leaflets, fusing at 125° and boiling at 288°. It is soluble in hot water, easily in alcohol and ether. It possesses weak basic properties. The hydrogen of the carboxyl of benzoic acid can also be sub- stitued by hydrocarbon rests, forming esters, e.g., methyl benzoic ester, C6H5"COOCH3, ethyl benzoic ester, C6H6"COOC2H5, etc. These esters are made by dissolving benzoic acid in the SUBSTITUTED BENZOIC ACIDS. 243 proper alcohol, and leading chlorhydric acid gas through the solution. The esters Can also be easily made by acting on the alcohols with benzoyl chloride. Benzoyl chloride reacts with water, forming benzoic acid and chlorhydric acid : C6H5-C0C1 + HOH = C6H5-COOH 4- HCl. If instead of water, an alcohol (substituted water) is taken, an ester and chlorhydric acid are produced : C6H5-C0C1 4- CH3OH = C6H5-COOH3 + HCl. In this manner phenyl benzoic ester, C6H5~COOCgH5, is obtained. It crystallizes in colorless prisms, which fuse at 66°, and are volatile without decomposition. The derivatives which we have thus far considered have been produced by substitutions in the carboxyl. We shall now take up those in which the substitution takes place in the benzene nucleus. Monochlorbenzoic acid, C6H4C1~C00H. There are three compounds of this composition, which bear different names. ( 1 CI 1) Chlorsalylic Acid, C6H4 \ ~ COOH' *s Pr°duced by the action of phosphorus chloride on sodium salicylate (see later). It forms colorless crystals fusing at 137°, which are converted into benzoic acid by the action of nascent hydrogen, and into salicylous acid by fusing potassium hydroxide. C6H4CrC02H + KHO = C6H4(OH)C02H + KC1. Chlorsalylic acid Salylic acid (1 CI 2) Chlorbenzoic Acid, C8H4 -j „ (wym is obtained directly from ben- zoic acid by the action of chlorine. Colorless needles fusing at 152°. 3) Chlordracylic Acid, C6H4 -j . COOH' *s Pr°duced by the oxidation of monochlortoluene (1. 4). Colorless scales fusing at 237°. The three brombenzoic acids, the three iodobenzoic acids, and the three nitrobenzoic acids are also known. 244 AROMATIC COMPOUNDS. Nitroberizoic Acid, CsH4 X02)~COOH, is formed by the action of fuming nitric acid on benzoic acid. The metanitrobenzoic acid is the chief product, the other two being obtained in lesser amounts. The metanitrobenzoic acid forms needles fusing at 141°. The ortho-compound is also formed by oxidation of orthonitrotoluene. It forms prisms fusing at 14?:. The para-compound, which is also obtained by the oxidation of nitrotoluene, forms leaflets fusing at 238J. They are changed by reduction into amido-acids, which under the proper conditions yield azoxy-, azo-, and hydrazo-compounds. The nitrobenzoic acids yield, when boiled with alcoholic potassa, C6H4(C02H)-X\ Azoxybenzoic Acids, ^CO^/0' Sodium amalgam, converts the nitrobenzoic acids into azobenzoic acids, C,H4(COOH)-X , n . • **,,.• ii which by further reduction pass into hydrazobenzoic C6H4(COOH)-N' C6H4 COOH)"XH M ., ., , , acids i . which by the action of silver oxide are converted ' C6H4(COOH)"XH' J back into the azo-compounds. There are also four dinitrobenzoic acids, C6H3(N02)2COOH, and one trinitrobenzoic acid, C6H2(X02)3COOH, known. AmidobenzoicAcids,C6H4(XH,)C00H. Theamidobenzoic acids correspond to the nitrobenzoic acids. All three of the monamidobenzoic acids are known. They possess basic prop- erties and unite with acids to form salts, but since they contain the carboxyl group, the hydrogen of which can easily be sub- stituted by metals, they also possess acid properties. This compound may be compared to glycocoll (p. 98). CH2(XH2)~C00H Glycocoll, C6H4(NH2)"C00H Amidobenzoic acid. The aromatic compounds, however, exhibit some characteristic differences. The three amidobenzoic acids have also different names : Anthranilic Acid, C6H4 jg COOH' is formed b7 heatiDS indigo-blue with potassium hydroxide and manganese di-oxide. It crystallizes in glittering yellow leaflets, difficultly soluble in cold water, and easily in AMIDOBENZOIC ACIDS. 245 hot. It fuses at 144°, and sublimes without decomposition. It unites with both bases and acids, forming finely crystallizable compounds. On rapid heating, it breaks into aniline and carbonic acid : C6H5(NH2)COOH = C6H5-NH2 + C02. Amidobenzoic Acid, C6H4 \ „ COOTI' *s obtained from the correspond- ing nitrobenzoic acid by reduction with ammonium sulphydrate. Color- less prisms fusing at 173°, subliming without decomposition, difficultly solu- ble in cold water, easily in hot. It forms salts with both acids and bases. Its ethyl ester, CoH4(NH2)COOC2H5, and amide, C6H4(NH2)CO(NH2), are worthy of notice. Amidodracylic Acid, C6H4 -j . POOH' *s Pr°duced °y the reduction of nitrodracylic acid with ammonium sulphydrate. It forms colorless rhombohedrons fusing at 186°, and otherwise resembles amidobenzoic acid. Nitrous acid converts the amidobenzoic acids into diazo-compounds. The diazo-compounds of amidobenzoic acid have been the more thoroughly examined. If nitrous acid is passed into an alcoholic solution of amidobenzoic acid, small orange crystals separate, which are the amidobenzoic compound of diazobenzoic acid : 2 C6H4(C02H)NH, 4. HN02 = CeH4(C02H)-N=N-NH(C02H)C6H4 4- 2H20. If nitrous acid is conducted through an aqueous solution of amidoben- zoic acid, however, diazobenzoic acid nitrate is obtained : C6H4(C02H)XH2. HN03 + HN02 = C6H4(C02H)-N=N-X03 + 2 H20. The nitric acid rest, X03, of diazobenzoic acid nitrate can be replaced by CI, HS04, etc., in which case the chloride, sulphate, etc., of diazoben- zoic acid are formed. On boiling with water, the diazobenzoic acid com- pound is decomposed, and at the same time, also, the diazobenzene, the double atom of nitrogen being eliminated and hydroxyl taking its place : C.H«(CO,H)-N=N-NO, 4 H20 = C6H4(C02H)OH + N2 4 HN03. An hydroxybenzoic acid is thus obtained. Of the higher amidated benzoic acids, we shall mention only the diamidobenzoic acid, C6H3(NH2)2COOH, which is obtained by the reduc- 246 AEOMATIC COMPOUNDS. tion of dinitrobenzoic acid, C6H3(N02)2COOH. It is difficultly crystalliz- able, owing to its remarkable solubility. As the amido-groups predomi- nate, it does not possess acid properties, i.e. does not unite with bases, but forms salts with two molecules of acid. Since an H of benzene can be replaced by the group S03H, forming benzenesulphonic acid, C6H5~S03H, an H of the benzene nucleus of benzoic acid can also be substituted by S03H, yielding sulphobenzoic acid. Benzoic acid and sulphuric anhydride yield sulphobenzoic acid, l OA XT C6H4 ]nQ3jj, a deliquescent, easily decomposable compound, which is dibasic, and forms two series of salts, of which the beautifully crystalliz- able acid barium salt is worthy of mention. Sulphobenzoic acid can be nitrated. One or both of the hydroxyls can be replaced by CI, forming C6H4 j cobl ' su^ptiobenzoyl chloride, and C6H4 -j qqcj . sulphobenzoyl dichloride. With ammonia, these compounds exchange their CI for NH, yielding CCH4 j cONH2' sulPhobenzamic acid, and C„H4 \ qo(NH )' sulphobenzamide. Benzoic acid and benzaldehyde have been shown to be de- rivatives of benzyl alcohol, which is a true alcohol, and has also the characteristic properties of an alcohol of the fatty series. We shall take up next the consideration of some of its derivatives. As we have already seen (p. 233), benzyl chlo- ride is formed by leading gaseous chlorhydric acid through benzyl alcohol, in the same manner that ethyl chloride is formed from ethyl alcohol : C6H5CH2OH + HCl = C2H5CH2C1 + H20. As benzyl chloride behaves as a fatty compound, its chlo- rine is easily replaceable. On boiling benzyl chloride with water, benzyl alcohol is regenerated: C6H5CH2C1 + HOH = C6H5CH2OH + HCl. BENZYLPHOSPHINE. 247 By digestion with alcoholic ammonia, benzyl chloride is converted into the hydrochlorides of benzylamine: C6H5 CH2!N"H2, dibenzylamine, (C6H5~NH2)2NH, and tribenzylamine : (C6H5"CH2)3N. Benzylamine, C6H5"CH2"NH2, is a liquid boiling at 133°, miscible with water, and possessing strong basic properties. Dibenzylamine, (C6HS"NH2)2NH, is a liquid insoluble in water. Tribenzylamine, (C6H5~CH2)3N, is a crystalline body fusing at 91°, and insoluble in water. With phosphuretted hydrogen (phosphine) benzyl chlo- ride forms the corresponding phosphines, benzylphosphine, C6H5"CH2"PH2, dibenzylphosphine, (C6H5"CH2)2PH, and tribenzylphosphine, (C6H5~CH2)3P. Chlorbenzyl forms with potassium cyanide, benzyl cyanide, C6H5"CH2C]Sr, which on boiling with potassa yields an acid homologous with benzoic acid, C6H5~CH2~COOH, alphatol- uic acid, or phenylacetic acid: C6H5CH2C¥ + 2H20 = C6H5CH2COOH + NH3. By boiling chlorbenzyl with potassium sulphydrate, the sulphur compound corresponding to benzyl alcohol is pro- duced. It is the mercaptan of the benzyl series, and is called benzylsulphydrate: C6H6CH2C1 + KHS = C6HSCH2SH + KC1. It is a colorless liquid with an offensive odor. Its properties resemble those of ethylmercaptan. The benzyl sulphide, (C6H5~CH2)2S, and benzyl disulphide, (C6H5_CH2)2S2, have also been produced. There is a body derived from benzoic acid, which occurs in the animal organism and is called benzoylglycocoll, or hippuric acid, C9H9N03 : 248 AROMATIC COMPOUNDS. CH'COOH Glycocoll = C2H,SN02 = . 2 J 2 5 2 NH^ • ., ^ TT ™ CH2"COOH Hippuric acid = CqH9J\0, = i ^ 993 NH-CO"C6H5 Hippuric acid occurs as calcium and sodium salts in the urine of the herbivora, and owes its origin to benzoic acid ; for, after eating substances containing benzoic acid, hippuric acid is always found in the urine. In fact, the whole amount of benzoic acid taken into the system is thrown off in the urine as hippuric acid. It crystallizes in thick needles, which fuse on heating and decompose by further heating. It is difficultly soluble in water, and forms soluble salts. It is monobasic. On boiling with acids, or alkalis, it breaks into glycocoll and benzoic acid, taking up the elements of water : PIT "COOTT . 2 4-H20 = CH2(NH2)COOH + C6H5COOH. NH-CO"C6H, 2 2V 2y ^<>5 It can be made artificially by the action of benzoyl chloride on silver- glycocoll : r, xx ™™ CH2"C00H CH2"COOH C6H5C0C1 +i =i 4- AgCl. NHAg NH-COC0H5 The di-valent rest, NH, is replaced by 0 by the action of nitrous acid, forming CHTCOOH Benzoylglycollic acid, i _ _ , or C9H804, which is glycollic acid in which the alcoholic hydrogen is replaced by benzoyl. CH2_COOC2H5 Ethyl hippuric ester, i , and its derivative, hippuramide, NH CO~C6H5 CH2"CONH2 i , are also easily produced. NH-CO_C6H6 We shall pass over a large number of the benzyl derivatives, as they are produced in an exactly analogous manner to their corresponding de« rivatives in the ethyl series. 0RCIN0L. 249 There are nine dihydroxyl derivatives of toluene possible according to the theory, six having the constitution : C6H3(CH3)(OH)2, and three the constitution, C0H4(OH)CH2(OH). The first six correspond to the dihydroxyl derivatives of benzene, and resemble quinol, catechol, etc., while the latter three possess both alcoholic and phenol characteristics. Only a few of these possible compounds are known. Orcinol, or orcin, C,H802, belongs to the first six. Orcinol: C6H3->OH OH OH CH, is a decomposition-product of many coloring matters derived from lichens (rocella and lecanor). It is also formed by heat- ing potassium monochlortoluene-sulphonate with potassium hydroxide : (CI (OH C6H3 \ S03K + 2 KOH = C6H3 1 OH 4- KC1 + KoS03. (CH3 (CH3 It crystallizes in prisms fusing at 86° and boiling at 290°. Ferric chloride colors it dark violet. On exposure to the air, it takes on a red color owing to partial oxidation. If ammonia is also present, a red coloring matter called orcein is formed, which is a weak acid and dissolves in alkalis with a purple color, and is precipitated again as a red powder by acids. Orcein is the principal constituent of the coloring matter known as archil. If sodium carbonate is added to an ammoniacal solution of orcein, and the mixture exposed to the air, a bluish-violet liquid is obtained, from which acids precipitate a red powder called litmus. 250 AROMATIC COMPOUNDS. ( OH A methyl .ether of orcinol is known, C6H3 -j OCH3, oi ( CH3 C8H10O2, beta-orcinol. It is also a product of the decom- position of many lichen coloring matters. We know also another ether of a dihydroxyl-toluene, viz., (OH cresol, C6H3 \ OCH3, or C8H10O2. (CH3 Cresol occurs in beech-wood tar, together with the mono- methyl ether of catechol, guaiacol, C6H4 < qtt 3. Both beta- orcinol and cresol are oils which give precipitates with most of the metallic solutions. They yield, when treated with potassium chlorate and chlorhydric acid, compounds homologous with chloranil, as: C7II8C1408 and C8H4C1402. There are two compounds met with in commerce under the name of creasote which are essentially different : 1) Coal-tar creasote, which consists principally of phenol with small amounts of cresol, guaiacol, catechol, and phlorol. The so-called crystal- lized cresote is phenol. 2) Beech-tar creasote, consisting chiefly of cresol and guaiacol. Chlorinated quinones and quinones of toluene can be pro- duced in the same manner as the chlorinated quinones of benzene. Trichlortoluenequinone, C6C13 -] pfj- , and trichlor- ( O TT toluquinol, C6C13(CH3) < ^tt, and their derivatives have been obtained. Only one member of the second class of dihydroxyl-deriv- atives of toluene, which are partly phenols and partly alco- hols, has been obtained, viz., salicyl alcohol, or saligenin, CCH4 \ ^ CHo0H' the aldenyde> ceH4 | CHO' and tllc aci(*5 SALICYLOUS ACID. 251 (OH C6H4 j QQQTT, derived from it are also known. The methyl ether of an isomeric salicyl alcohol is also known, viz., anisyl alcohol, C6H4 -J . prx ^tt, as well as the ( OCH corresponding aldehyde, C6H4 -j Xtjq3, and acid, fl TT ( OCH3 U6l±4 I COOH' The three acids corresponding to the three alcohols are all known. They are salicylic acid, C6H4 -j 2 p^ tt, hydroxy- benzoic acid, C6H4 -j o pr\ it, and parahydroxybenzoic acid, 0«H4|1° 4CO,H' Salicylous Alcohol, or Saligenin, C,H8.02, is produced by the action of a ferment on salicin : C13H180, + H20 = C6H1206 + C7H802. Salicin Sugar Saligenin Saligenin crystallizes in mother-of-pearl tablets, fusing at 82°. It is difficultly soluble in water, is colored blue by ferric chloride, and by oxidation is converted into salicylous aldehyde and salicylous acid. Dilute acids change it into a resin, saliretin, C, 4Hj 4 0 3. Salicylic Aldehyde, or Salicylous Acid: C,H602, C6H4(OH)CHO, occurs in the Spirea ulmaria. It is formed from salicin by the action of oxidizing agents, and, together with parahydr- oxybenzoic acid, by the action of chloroform on an alkaline solution of phenol : CHC13 + C6H5(OH) + NaHO = C6H4(ONa)CHO + 3 NaCl + 3 H20. 252 AROMATIC COMPOUNDS. By the action of sodium hydroxide on chloroform, formic acid is formed: CHC13 + 3 NaHO = CHOOH 4- H20, Which in the nascent state unites with phenol, water being eliminated : CcH6(OH) 4 CHOOH = C6H4(0H)-CH0 + H20. This reaction corresponds exactly to the action of carbonic acid on sodium phenoxide (see under salicylic acid), except that in the one case the aldehyde, in the other the acid, is formed. It is a liquid with the odor of bitter almonds, boiling at 196°. It is slightly soluble in water, easily in alcohol. It possesses weak acid properties, and, since it is an aldehyde, unites with acid sulphites. Ferric chloride colors it violet-red. Chlorine, bromine, and nitric acid convert it into substitu- tion-products. Salicylous acid is isomeric with benzoic acid. Salicylic Acid, C7H603, CcH4(0H)C00H. The methyl ester of salicylic acid forms the chief constituent of winter- green oil (Gaultheria procumbens). Salicylic acid is formed by fusing salicin, or curmarin, with potassium hydroxide. It crystallizes in prisms fusing at 156°, and is difficultly soluble in cold water, easily in hot. It is properly a monobasic acid, but as it is also a phenol it unites with two molecules of strong bases, such as the alkalis and alkaline earths. Ferric chlo- ride produces a violet color with its salts. On distillation with lime, it breaks into phenol and carbonic acid : C6H4(OH)C02H = C6H5(OH) + C02. It can be produced synthetically by adding small pieces of sodium to hot phenol and passing carbonic acid through the mixture. In this way, sodium salicylate is obtained : C6H5OH + 2 Na + C02 = C6H4(ONa)C02Na + 2 H. Sodium salicylate is also formed when sodium phenox- SALICYLIC ACID. 253 ide, which is formed from phenol and sodium hydroxide, is heated to 180°, and exposed to a stream of carbonic acid. In this reaction, half of the phenol is regenerated : 2C6H50Na + C02 = C6H4(0Na)C02Na + C6H5OH. This method is used to produce salicylic acid commercially. Salicylic acid has no odor. Its taste is powerfully astringent. It has marked antiseptic properties, and is largely used in the arts as an antiseptic for preserving fruits, wines, etc., and in medicine also as an antiseptic, and in the treatment of many diseases (diphtheria, rheumatism, etc.). It yields substitution products with chlorine, bromide, iodine, and nitric acid. Its anhydride, CeH4 j ^q \ has also been produced. Nitrosalicylic Acid, C6H3(N02)OH . COOH, which is obtained by acting on salicin with nitric acid, yields on reduction amidosalicylic acid, C6H3(NH2)OH. COOH. It possesses acid properties. By the action of ammonia on wintergreen-oil, salicylamide, C0H4(OH)CO(NH2), is obtained: C°Ri \ COOCII. + NHa = CeH4 | CONH2 + CH4°- Salicylamide crystallizes in leaflets fusing at 132°, and boiling at 290° with decomposition, a molecule of water being eliminated, forming sali- cylimide : i OH /NH C«R* icONH2 = CeH4\C0 +H2°' Which is insoluble in water, alcohol, and ether. Hydroxbenzoic Acid, Oxybenzoic Acid, C6H4 j „ qq jt, or C7H603. As we have already seen, nitrous acid converts amidobenzoic acid into diazobenzoic acid nitrate, which decomposes with water into hydroxybenzoic acid. Metahydroxybenzoic acid is also formed by fusing metasulphobenzoic acid with potassium hydroxide. Hydroxybenzoic acid forms small, colorless, indistinct crystals fusing at 200°, and slightly soluble in water. It is a 254 AROMATIC COMPOUNDS. monobasic acid, and yields easily substitution products. Its salts are not colored by ferric chloride. Parahydroxybenzaldehyde, Paroxybenzaldehyde, C6H4 \ ^ CHO' *s formed, besides salicylaldehyde, by the action of chloroform on phenol. It is separated from the latter by distilling the acidified liquid with water, the salicylic aldehyde distilling over with the steam, while the parahy- droxybenzaldehyde remains behind, and on cooling crystallizes from the liquid. It forms needles fusing at 115-116°. It is difficultly soluble in water, and its aqueous solution is colored a dirty violet by ferric chloride. Parahydroxybenzoic Acid, Paroxybenzoic Acid, C6H4 | 4 qq u> or Ct,H603, Is formed in the same manner from amidodracylic acid, as hydroxybenzoic acid from amidobenzoic acid. It is also obtained by passing carbonic acid over potassium phenoxide. Heated to 200°-210°, in the same manner as salicylic acid, it crystallizes in colorless prisms fusing at 210°. Its reactions are analogous to those of its isomeric acids. ( 1 OCIT Anisyl Alcohol, C6H4 -J . Xjx Att, is the methyl ether of the alcohol derived from parahydroxybenzoic acid. It is made from anisyl aldehyde, and forms colorless needles fusing at 25° and boiling at 258°. ( OCH Anisyl Aldehyde, C6H4 -j pxrr)3? is obtained from anise-oil or fennel-oil by heating with dilute nitric acid. It is a color- less liquid boiling at 248°, with a spicy odor. It forms crys- talline compounds with acid alkali sulphites, and is oxidized by the oxygen of the air into anisic acid. Anisic Acid, C6H4 -j qq A, is made from anise-oil, or di- rectly from anisyl aldehyde. It is also obtained artifically by DIHYDROXYBENZOIC ACIDS. 255 methylating parahydroxybenzoic acid. Colorless needles fus- ing at 185°. It is a monobasic acid. The carboxyl derivatives are the only other hydroxyl deriva- tives of toluene which are known. 1) The principal representatives of the six theoretically possible acids, C6H3 \ ^L jj, are hydroxy salicylic acid (1.2. 5), parahydroxysalicyiic acid, and protocatechuic acid (1.3. 4). Hydroxysalicylic and parahydroxysalicyiic acids are formed from the corresponding amides of salicylic acid, by conversion into the diazo-compounds, and then into .the hydroxyl-com- pounds. Protocatechuic acid is a decomposition-product of many tannic acids (catechin, etc.). It crystallizes in color- less needles containing a molecule of water, which fuse at 199° and then break into carbonic acid and catechol. The dimethyl ether of protocatechuic acid, C6H3 -j qqqjj ' is known as veratric acid, and exists in sabadilla-seeds. It forms needles fusing at 180°. The methyl ether of the aldehyde of protocatechuic acid, ( OCH3 CBH3 \ OH , is intimately related to protocatechuic acid. (CHO It occurs in the vanilla bean and is called vanillin. Vanillin is formed by the oxidation of a substance, G10Hj 203, obtained from coniferin (see later). It crystallizes in needles, fusing at 80°, and possesses an intense odor of vanilla. The decomposition-product, Ci0Hi2O3, which is obtained directly from (OCH3 coniferin, has probably the constitution, CnH3 -CH-CcH4CH3, DiphenyUolylmethane, of which it is the triamido derivative : NH2"C6H4\ pH_r H /CH3 NH2-C„H4/CH UH3\NH2* ROSANILINE. 259 Rosaniline hydrate, C20H2iN3O, however, is the hydroxyl derivative of leucaniline, and has the constitution : (NH.rCGH4)2=C(OH)-C6H3<^£. The compound, C2oHi0N3, the salts of which constitute fuchsine, is a peculiar condensation-product of rosaniline, formed by the elimination of water : NH2"CCH4\ /C6H3-CH3 nh2-c6h4/ \NH The salts of leucaniline yield fuchsine again by oxidation. It is easy to see that compounds similar to fuchsine will be formed when instead of toluidine higher methylated anilines are heated with weak oxidizing agents. The atoms of hydrogen which are in combination with the nitrogen can easily be replaced by hydrocarbon rests. By heating rosaniline with methyl iodide, or chloride, methyl violet is obtained. It can also be produced by heating di- methylaniline with cupric nitrate and salt. It has the com- position, C20H14(CH3)5]Sr3 . HCl. The ethyl violet corre- sponds with it in every way. On heating rosaniline with aniline at 180°, a blue coloring matter, aniline blue, is ob- tained, which is a triphenylrosaniline : C20Hi«(C6H5)3N3. HCl. Methyl violet in the dry state is golden yellow. Aniline blue is a bluish-brown powder with a coppery luster. Iodine green has the composition : C20H14(CH3)5N3.CH3Cl + H2O, and crystallizes in prisms with a superb cantharides-green metallic luster. It is formed by heating rosaniline acetate with methyl chloride and methyl alcohol. Besides fuchsine, there is formed by the action of arsenic acid, etc., on aniline containing toluidine, the salt of another 260 AROMATIC COMPOUNDS. base, which on account of its yellow color is called chrysani- line, Cg0H17N3. Crysaniline unites with one and two molecules of acids to form salts. We have, then : Chrysaniline, C20H11N3 Eosaniline, C20H19N3 Leucaniline, C20H21N3 And from rosaniline : Pentamethylrosaniline, C20H14(CH3)5N3 ) yielding aniline Penta-ethylrosaniline, C20H14(C2H5)5N3 f violets. Triphenylrosaniline, C20H16(C6H5)3N3 | ^[ding aniline Under the name of mauve, a violet dye is met with in the arts, which is the hydrochloride of mauveine, C21H24N4. Mauveine is formed by the action of strong oxidizing agents, e.g., potassium chromate, on aniline containing toluidine. Its constitution is not known. If a solution of aniline in chlorhydric acid is treated with cupric chloride and potassium chlorate, a green precipitate is formed which becomes still more highly oxidized by the air, forming a black. It is called aniline-black. Its composition is not known. Rosolic Acid, C20H16O3, stands in intimate relation with rosaniline. Its constitution is either : C6H3(CH3)(OHK /C6H4 C6H4(OH)_____/ \6 C6H4(OHK /C6H3"CH3 C6H4(OH)/ \6 It is formed by heating phenol with oxalic acid and sul- phuric acid at 150°. It forms glittering red prisms with a XYLENE. 261 blue or green reflex. It fuses with decomposition over 220°. Reducing agents convert it into leucorosolic acid, C20H18O3, which crystallizes from glacial acetic acid in thick, colorless prisms. Leucorosolic acid is the trihydroxyl-derivative of diphenyltolyme- thane, and rosolic acid is the oxidation product of it. Xylene. Only the more important of the benzene derivatives which contain more hydrocarbon rests than one methyl, will be con- sidered. When two H's of benzene are substituted by methyl- groups, three isomeric dimethylbenzenes are obtained : C6H4(CH3)2, or C8H10, which are also isomeric with ethylbenzene : C6H5~C2H5, or C8HI0. The dimethylbenzenes can be produced artificially. They occur, to- gether with benzene and toluene, in coal-tar, and are called xylenes. Ethylbenzene can only be obtained artificially. Dimethylbenzenes are formed from the corresponding chlor- or bromtoluenes by the action of methyl iodide and sodium; ethylbenzene from chlorbenzene, ethyl iodide and sodium. The xylenes boil at about 140°, ethyl benzene at 134°. They resemble benzene and toluene in their properties. Chlor-, brom-, and iodo-derivatives of them are known. The phenols of xylene and ethylbenzene are partly known. They pos- sess the characteristic properties of phenols, and are so little different from ordinary phenol, that they may be omitted. For similar reasons (PIT the alcohol derived from dimethylbenzene, C6H4 -j qxi3qtj) tolyl alcohol, will not be further considered. The acids derived from xylene and ethylbenzene, however, possess a greater interest: C«H^C023H' C«HKc02H and C6H5-CH2-C02H. 262 AROMATIC COMPOUNDS. If a dimethylbenzene is treated with oxidizing agents, the methyl is oxidized into carboxyl, and there is produced, ac- cording to the energy of the oxidation : [ CTT CCH4 j qqqjp Toluic acid, or C6H4 j riQQjrj Phthalic acid. By oxidation of ethylbenzene, however, the carbon atom which is united to the benzene-nucleus is oxidized so that carbonic acid and benzoic acids are obtained : C6H5"CH2-CH3 + 3 02 = C6H5COOH + C02 + 2 H20. There is, however, an acid known which is isomeric with the three toluic acids, and which is a derivative of ethylbenzene, viz., phenylacetic acid, or alphatoluic acid: C6H5"CH2"COOH. There are hence three toluic acids and three phthalic acids, and, in addition, the alphatoluic acid. Orthotoluic acid, C8H802, forms long fine needles fusing at 102°, metatoluic acid, needles fusing at 109°, and paratoluic acid, colorless needles fusing at 178°. Alphatoluic Acid is obtained by boiling benzyl cyanide with potassa, and forms leaflets resembling benzoic acid, which fuse at 76.5° and boil without decomposition at 261-262°. By oxidation with potassium chromate and sulphuric acid, the three toluic acids are converted into the three correspond- ing phthalic acids, while the alphatoluic acid is transformed into benzoic acid. Phenylglycollie, or Mandelic Acid, C6H5"CH(OH)~COOH, is a derivative of alphatoluic acid, or phenylacetic acid, and stands in the same relation to phenylacetic acid as glycollic acid to acetic acid : PHTHALIC ACID. 263 C6H5-CH2-COOH C6H5-CH(OH)-COOH Benzoic acid Phenylglycollie acid H"CH2-COOH H"CH(OH)"COOH. Acetic acid Glycollic acid Mandelic acid is formed by boiling a mixture of benzalde- hyde and cyanhydric acid with chlorhydric acid : C6H5"CHO + Cmi + 2 H20 = C6H5_CH(OH)-COOH + NH3, the reaction being analogous to the formation of lactic acid from acetaldehyde. It crystallizes in tablets or prisms fusing at 115°. It is converted into phenylglyoxylic acid by oxidation with dilute nitric acid. On further oxidation it passes into benzaldehyde and car- bonic acid, and finally into benzoic acid. Iodohydric acid reduces it to alphatoluic acid. Phenylglyoxylic acid, C6H5~C0~C00H, can also be obtained by the decomposition of benzoyl cyanide. It forms crystals fusing at 66°. When the toluic acids are treated with oxidizing agents, the second methyl group is, as we have seen, also oxidized to car- 0. Numerous chlorine and nitro-substitutions of it are known. Phthalic anhydride forms long, glittering needles fusing at 127° and boiling at 277°. 264 AROMATIC COMPOUNDS. (1 COOTT 2) Isophthalic Acid, C6H4 j i COOH' is usuall7 made by the oxidation of the xylene contained in coal-tar. It crystal- lizes in fine needles fusing over 300°, and is difficultly soluble in hot water. (1COOH 3) Terephthalic Acid, C6H4 -j . nr)OH' ^s Gained, besides isophthalic acid, by the oxidation of the xylene from coal-tar. It is an amorphous powder which sublimes at a high tem- perature without fusing. All three of the phthalic acids yield benzene by distillation with lime: C6H4(COOH)2 = C6H6+2C02. Of the numerous other derivatives of the hydrocarbon, C8H10, we shall only mention the amido-compounds. The mixture of dimethylbenzenes and xylenes, which are contained in coal-tar are converted by the action of nitric acid into nitro- xylenes, and these by reduction into amidoxylenes. These amidoxylenes, form a mixture of extremely similar bodies which have not yet been separated, and hence bear the com- mon name of xylidine. Xylidine is an oily liquid boiling at 216°, and resembling aniline very much. With reagents, it yields derivatives analogous to those of aniline. Like aniline, xylidine possesses basic properties. By treating phthalic anhydride with phenol and concentrated sul- phuric acid, phenolphthaleln is formed : c tt n — CBH4(OH)\ p/CeH4\pn L20H14O4 - c6H4(OH)/°\0___/C0- It is a yellowish-white powder which is soluble in alkalis with a red color. On boiling its alkaline solution with zinc dust, it takes up two atoms of hydrogen, yielding phenolphthalin: C tt o _CbH4(OH)\p/C,H4-COOH, 02„U16U4 _ c6H4(OH)/°\H FLUORESCEIN. 265 which crystallizes in small needles, and is easily oxidized into phenol- phthalein. It is soluble in concentrated sulphuric acid, with a reddish yellow color. From this solution, water precipitates phenolphthalidin, C2oHi403 : C.H4(OH)-7C C„H3(OH)—C(OH)/CsH4' as a yellowish-green precipitate. Phthalidin is converted by oxidizing agents into phenolphlhalideln, C20Hl4O4, which is isomeric with the phthalein. The various hydroxyl derivatives of benzene, as catechol, resorcinol, quinol, orcinol, pyrogallol, etc., behave like phenol. The following compounds are of importance : Resorcinol-phthaleln-anhydride, fluorescein: c. tt n — C6H3(OH)2\p /C6H4\pn C20H12O5 - c6H3(OH)2/°\0__/°0' which is formed by heating phthalic anhydride with resorcinol at 200°. It is a yellowish-red powder which is easily soluble in alkalis and alka- line carbonates, and in dilute solution possesses a beautiful yellowish- green fluorescence. Bromine converts it into tetrabromfluorescew, eosin, CjoHbB^Os, which crystallizes from alcohol in flesh-colored crystals. It is quite a strong dibasic acid and yields beautifully crystallizable salts. Its alcoholic solution, on the smallest addition of an alkali, assumes a beautiful yellowish-green fluorescence. The potassium salt, C20HBBr4O5K2, crystallizes with varying amounts of water, and is a valuable dye. On evaporating fluorescein with an excess of sodium hydroxide solu- tion, one molecule of resorcinol splits out, and mono-resorcinol-phthaleln, Ci4H)0O5, is produced. On treating eosin in the same manner, dibrom- resordnolphthaleln: P jj /CO-C6HBr,(OH)2 u±±4\COOH is obtained. On heating pyrogallol with phthalic anhydride at 200°, gallein, k2oHi4Oo: °>. is formed. It is a brownish-red powder which dissolves in potassium and sodium hydroxide solutions with a blue color, and in ammonia with a 266 AEOMATIC COMPOUNDS. violet color. It loses the elements of water at 180°, and is converted into galleln anhydride, C20Hi2O7. Nascent hydrogen converts it into gallin, C2oHi8Ot. We see from the above, that phthale'in is a derivative of triphenyl- methane : C6H5\ p /CeHs C6H5/°\H ' and stands in intimate relation to rosolic acid, and hence also to rosani- line. Cumene. The derivatives of benzene which contain nine carbon atoms are represented by three trimethylbenzenes : C6H3(CH3)3, three methylethylbenzenes, C6H4(CH3)(C2H5), and two pro- pylbenzenes, C6H5~C3H1. All of them have the general formula, C9H12. A mixture of two trimethylbenzenes ^ occurs in coal-tar. One is pseudocumene, (1.3. 4). The other, which can also be obtained by treating acetone with dehydrating agents, is called mesitylene: 3 CH3"CO"CH3 = C6H3(CH3)3 + 3 H20. This peculiar condensation of acetone takes place in the following manner. The oxygen of each molecule of acetone unites with two hydro- gen atoms of another molecule, forming a double binding between each of the molecules. The trimethylbenzene thus produced contains the methyls in the 1.3.5 position. These hydrocarbons are distinguished chiefly by the differ- ences in the properties of their nitro-compounds. Two of the methylethylbenzenes are known. They are made by ethyl- ating toluene. CUMENE. 267 Isopropylbenzene, or Cumene, is obtained by distilling cumic acid with lime, and also from brombenzene and propyl bro- mide. According to the energy of the oxidation, the trimethylbenzenes yield three oxidation-products : /CH3 /CH3 /COOH C6H3^-CH3 , C6H3^COOH, C6H3^COOH. \COOH \COOH \COOH Methylethylbenzene, however, c H /C2H5 r R /CH3 p jr /COOH U6±l4\COOH' °6±i4\COOH' C,iH4\COOH' as the ethyl group is oxidized into carboxyl. Propylbenzene yields only benzoic acid. The three trimethylbenzenes boil between 163-165°; methyl- ethylbenzenes from 159-162°; propylbenzene at 157°, and cu- mene at 151°. The pseudocumene, which occurs in coal-tar, yields the following pro- ducts on oxidation. (1CH3 Xylic acid, C6H3 <3 CH3 , or C0H10O2, which crystallizes in prisms (4 COOH fusing at 126°. (1COOH Paraxylic acid, C6H3 ^3 CH3 , or C9H10O2, crystallizing in prisms (4CH3 fusing at 163°. (1COOH Xylidic acid, C6H3 43 CH3 , or C9H804, amorphous and fusing at (4 COOH 282°. (1CH3 The mesitylene, C6H3 •< 3 CH3, which is obtained from acetone, yields (5CH3 on oxidation with dilute nitric acid : (1CH, Mesitylenic acid, C6H3 <3 CH3 , or C9H,0O2, crystallizing in needles (5 COOH fusing at 166°. 268 AROMATIC COMPOUNDS. (1CH3 Uvitic acid, C6H3 \% COOH, or C9H604, needles fusing at 288°. (5 COOH (1 COOH Trimesic acid, C6H3 \ 3 COOH, or C9H606, which crystallizes in prisms (5 COOH soluble in water, fuses at above 300° and sublimes without decomposi- tion. The two other tricarboxylic acids, C9H606, isomeric with trimesic acid, are also known. They are produced from mellitic acid (see later), and are called trimellitic acid (1.2. 4), and hemimellitic acid (1.2. 3). The third trimethylbenzene has not yet been examined. There remains still to be mentioned an acid which is derived from paramethylethylbenzene. It is not directly obtainable from it, but from di-ethylbenzene. It is ethylbenzoic acid, ( C TT and its formula is, C6H4 -j rjQfm. ^ crystallizes in small prisms fusing at 110°. From isopropylbenzene is derived hydro-alropic acid : CoH5-CH/( COOH' which is formed by the reduction of atropic acid (see later). It is a liquid boiling at 265°. Benzopropionic acid, or hydrocinnamic acid: C6HrCH2-CH2-COOH, is a derivative of propylbenzene, although it cannot be directly produced from it. It is formed by the action of nascent hydrogen on cinnamic acid, and crystallizes in leaflets fusing at 47°. It is easily soluble in hot water, and is converted by oxidation into benzaldehyde and benzoic acid. Both of these acids are isomeric with xylic, paraxylic, mesitylenic, and ethylbenzoic acids. From propylbenzene there is also a group of compounds derived which occur in nature, and which stand in the same relation to propylbenzene as allyl alcohol to its aldehyde, viz., cinnyl alcohol, cinnamic aldehyde, and cinnamic acid: CINNYL ALCOHOL. 269 HCH2-CH2-CH3 C6H5-CH2-CH2-CH3 Propane Cumene HCH=CH-CH2(OH) C6H5-CH=CH-CH2(OH) Allyl alcohol Cinnyl alcohol HCH=CH_CHO C6H5-CH=CH-CHO Acrolein Cinnamic aldehyde HCH=CH_COOH C6H5_CH=CH-COOH Acrylic acid Cinnamic acid Liquid storax-balsam contains a body which, when purified by boiling the storax with sodium carbonate and crystallizing from a mixture of alcohol and ether, forms odorless and taste- less needles, fusing at 44°. It is called styracin, and is the cinnyl ester of cinnamic acid, C9H90~C9H,0. On boiling with potassa, styracin is decomposed into cinnyl alcohol and cinnamic acid: C9H90-C9H,0 + H20 = C.H, 00 + C9H802. Cinnyl Alcohol, C6H5_CH=CH_CH2(OH), or C9H10O, is phenyl-allyl alcohol; it is obtained by boiling styracin with potassa, and distils over with the steam, forming a colorless oil swimming on water. On standing, this oil solidifies to long, glittering needles, which have an odor of hyacinths. It fuses at 33° and distils unchanged at 250°. Cinnyl alcohol is but slightly soluble in water, easily in alcohol and ether. On heating with boric anhydride, it is converted into cinnyl ether, C9H9"0"C9H9, which is a liquid insoluble in water. When cinnyl alcohol is digested with gaseous chlorhydric acid, cin- namic chloride, or styrylic chloride, C6HS~CH=CH CH2C1 = C9H9C1, is formed. It is an oil insoluble in water, and converted by alcoholic ammonia into cinnamine, C9H9(NH2). Cinnyl alcohol is converted by oxidation into cinnamic alde- hyde. Cinnamic Aldehyde, C6H5"CH=CH"CHO, or C9H80, is formed by the oxidation of cinnyl alcohol, and also by heating 270 AROMATIC COMPOUNDS. a mixture of benzaldehyde and aldehyde with chlorhydric acid : C6H5"CHO + CH3"CHO = C6H5_CH=CH-CHO + H20. We have already had examples, under ordinary aldehyde, of this con- densation of two aldehydes with elimination of water. On digesting ordinary aldehyde with chlorhydric acid, water is eliminated, and two molecules of aldehyde unite, forming crotonic aldehyde (p. 139): CH3-CHO + CH3-CHO = CH3-CH=CH_CHO + H20. Cinnamaldehyde occurs in nature as the chief constituent of cinnamon-oil, from which it is usually made. It is a color- less liquid, insoluble in water and sinking therein. It has the odor of cinnamon, and, as it is an aldehyde, it unites with acid alkali sulphites, and is oxidized (by the oxygen of the air) to cinnamic acid. Cinnamic Acid, C6H5"CH=CH"COOH, or C9H802, is obtained, besides cinnyl alcohol, from styracin. It is present, together with styracin, in liquid storax, and is separated from it by treatment with sodium carbonate. The cinnamic acid drives out the carbonic acid and forms sodium cinnamate, which is soluble in water. Chlorhydric acid precipitates the free cinnamic acid from this solution. It also occurs in old cinnamon-oil, the cinnamic aldehyde having gradually become oxidized into the acid. It can be made synthetically by heating benzaldehyde with acetic anhydride and dry sodium acetate, in which case the latter acts as a dehydrating agent: 2 C6H5-CHO + (CH3_CO)20 = 2 C6H5-CH=CH-COOH + H20. The homologues of cinnamic acid can also be obtained by this method. Benzaldehyde and propionic anhydride give phenylisocrotonic acid, C6H,-CH=CH-CH2-COOH. Benzaldehyde and butyric anhydride, phenylangelic acid, etc. It forms prismatic crystals fusing at 133° and boiling at STYROLENE. 271 290°. It is difficultly soluble in cold water, easily in hot. With chlorine, bromine, iodine, and nitric acid, it yields sub- stitution-products. Its carboxyl-hydrogen is easily replaced by metals and hydrocarbon rests, forming salts and esters. Phosphorus pentachloride converts it into cinnamyl chloride, C9H,OCl, an oil, which with water decomposes into cinnamic m acid, Avith ammonia into cinnamyl amide, C9H,ONH2. On oxidation, it passes into benzaldehyde and benzoic acid. Nascent hydrogen converts it into hydrocinnamic, or phenyl- propionic acid, C,H ~CH~CH2"COOH. Sodium cinnamate C H 0\ and cinnamyl chloride yield cinnamic anhydride, ^^ q^O, a colorless, crystalline mass fusing at 127°, which also forms numerous substitution-products. When cinnamic acid is heated with lime, it breaks, analo- gously to benzoic acid, into carbonic acid and a hydrocarbon, styrolene, orphenylethylene, C8H8 : C9H802=C8H8+C02. Styrolene, Styrol, or Cinnamene, C6H5"CH=CH2, orC8H8, occurs in liquid storax, and is a colorless, strongly refractive liquid with an odor resembling that of benzene. It boils at 146° and is insoluble in water. When heated to 200° in closed vessels, it is converted into a solid and odorless mass, which is an isomeric styrolene, known as metastyrolene. Its formula is probably 3 C8H8. At 320°, it is transformed back into ordi- nary styrolene. When styrolene is heated to 170° with chlor- hydric acid, it is converted into an oily liquid, which is prob- ably 2 C8H8 distyrolene. Nitric acid converts styrolene into nitro-compounds. Bromine yields two addition-compounds, C H Br„, which, on heating with alcoholic potassa, are con- verted into bromstyrolene, C8H,Br, and then into phenyl- acetylene, C8H8 = C6H5"C=CH, an oil which boils at 140°. There are two esters of cinnamic acid which occur in nature, viz. : 272 AROMATIC COMPOUNDS. 1) Benzylcinnamic Ester, or Cinnamein, C9H,02 " C\H7. It occurs in balsams of Peru and Tolu. It forms small, glit- tering prisms with a pleasant odor and a sharp, spicy taste, which fuse at 39°. 2) Cinnamyl Cinnamic Ester, or Styracin, C9H702 ~C9H9, is also contained in liquid storax. It forms small, colorless needles without taste or smell, fusing at 44°. Cumaric Acid, Hydroxy cinnamic Acid, CQHaOo = CCH \l * ] 2 CH=CH_COOH' stands in intimate relation to cinnamic acid. It is obtained from cumarin (see later) and crystallizes in colorless needles fusing at 195°, and soluble in hot water. On fusion with potassium hydroxide, it yields acetic and salicylic acids : C6H4<^2 CH=CH-C02H + 3 KH0 = °6H4 \ 2 C02K + CH3-C02K + H2. Cumaric Anhydride, or Cumarin, C6H4 •] pfr=TH~f;Vv oc- curs in many plants (Asperula odorata), and especially in the tonka-bean. It is produced synthetically from the sodium compound of salicylic aldehyde and acetic anhydride. The acetyl compound of salicyl aldehyde, together with sodium acetate are first formed : p tt /ONa , CH3CO\n r w /0"CO-CH3 l\CHO + CH3"C02Na. The former compound splits out a molecule of water at a high temperature, forming cumarin : * * We have already had occasion to notice this elimination of water in aldehydes in the case of the artificial production of cinnamaldehyde. It occurs with aromatic compounds only when there are two side-chains in the ortho-position present. HTDROCUMARIC ACID. 273 r n /0"CO-CH3 _ P n j O'CO-CH , „ n 6 4\CHO ~" 6 4 (CH ===== + sU' Cumarin Cumarin, C9H602, forms colorless columnar crystals, fusing at 67° and boiling at 290°. It possesses a strong odor, which in the dilute state resembles that of the woodward. When boiled with potassa, it takes up water and is converted into cumaric acid. By the action of nascent hydrogen, it takes up a molecule of hydrogen and a molecule of water, and is changed into meli- lotic acid, C 9 H x 0 0 3, C9H6O2 + H2O+H2 = C9H10O3. Melilotic, or Hydrocumaric A cid stands in the same relation to cumaric acid as hydrocinnamic acid to cinnamic acid. It occurs with cumarin in sweet clover, from which it is obtained. It forms long colorless needles fusing at 82°, which are some- what soluble in water. On distillation, it splits out water forming the anhydride : C6H4-]pTT -qtt -Xq Hydrocumarin. Since cumarin can be produced artificially from sodium salicyl aldehyde and acetic anhydride, the homologues of cuma- rin can also be obtained by taking instead of acetic anhydride, propionic anhydride, butyric anhydride, etc. From a glucoside (see later) which occurs in coffee, and is called caffetannic acid, there is obtained an acid, C9H804 = C6H3(OH)2CH=CH"COOH, caffeic acid, or dihydroxycin- namic acid. It crystallizes in yellow leaflets, which are colored grass-green by ferric chloride. Fusing potassium hydroxide converts it into protocatechuic acid, C6H3(OH)2COOH, and acetic acid. By the action of nascent hydrogen, it is trans- formed into hydrocaffeic acid, C9H10O4. Umbelliferon, C9H603, contains one more atom of oxygen than cumarin. It exists ready formed in spurge-laurel, and 18 274 AROMATIC COMPOUNDS. can be obtained by the distillation of the resins obtained from the umbellifers (gum asafcetida, galbanum, etc.). Its con- X)H_____ stitution is C6H,^-0 | , and its relation to cumarin \CH=CH-CO is the same as that of hydroxybenzoic acid to benzoic acid. It forms prisms fusing at 240° which, when fused with potassium hydroxide, yield resorcinol, C6H4(OH)2, and are converted by nascent hydrogen into hydro-umbellic acid, C9H10O4 = C6H3(OH)2CH2CH2COOH, an isomer of hydrocaffeic acid : C9H603 + H20 + H2 = C9H10O4. Daphnetin, C9H604, which is formed from daphnin, and aesculetin, C9H604,from aesculin, are also to be considered as dioxycumarins. (Com- pare glucosides.) Cymene. There are only a few of the theoretically possible hydrocar- bons with ten atoms of carbon known. 1) Tetramethylbenzene, C6H2(CH3)4, durene, is formed from mono- brompseudocumene and methyl iodide. It fuses at 79' and boils at 190°. 2) Dimethyl-ethyl-benzene, C6H3(CH3)2(C2H6), is obtained from mono- bromxylene and ethyl iodide. It boils at 184°. 3) Di-ethyl-benzene, Cf,H4(C2H5)2, is produced from monobromethyl- benzene and ethyl iodide. It boils at 178°. 4) Methylpropyl-benzene, Cymene, C6H4 j o II ' CioHn> occurs in nature. It is contained in many essential oils, and is formed when essential oils of the formula C10H16, are heated with iodine, or when their dibromides are treated with alcoholic potassa. It is also formed by heating camphor with phosphorus sulphide. It is a liquid boiling at 175°, which yields on oxidation paratoluic and terephthalic acids. MELLITIC ACID. 275 5) Butylbenzene and Isobutylbenzene, C which on reduc- tion, affords amido-oxindole, C6H4 \ ^,^/ATXt -.-X^. Amido- ( Cri(JNli2) (j(J oxindole yields on oxidation with ferric chloride, cupric chlo- ride, etc., isatin, C6H4 J ^j-\ which by treatment with phosphorus pentachloride gives C6H4 i ^^_\ „, . This com- pound immediately splits out a molecule of HCl, forming : ORTHONITROPHENYLPROPIOLIC ACID. 283 uen4 -JCO-CCP which gives indigo-blue on reduction. From isatin there are also derived isatinic acid,C6Hi \ nQ-nQ tt , and dioxindole : r t. j NH-----f ^^ jcH(OH)-CO* Indole is probably C6H4 -j p^^xr. By treating orthonitrocinnamic acid with bromine, the di- bromide, C6H4^CH^r-CHBr-C0 H, is produced, which with sodium hydroxide yields orthonitrophenylpropiolic acid, C6H4<^£,^q2-qq tt. By the action of a weak reducing agent (grape-sugar) on this acid indigo-blue is formed : 2 C9H5N04 + 2 H2 = Gt .H, 0N2O2 + 2 H20 + 2 C02, By the action of sodium hydroxide alone, isatin is formed. By treating orthonitrophenylpropiolic ethyl ester with con- centrated sulphuric acid, it is converted into the isomeric isatogenic ethyl ester: C6H4^E0C2"C0^C^Hs = C6H4<^|^>C-C02C2H6. Owing to its instability the free acid has not been obtained. Isatogenic ester on reduction is converted into indoxylic ethyl ester: OH c; ? C6H4< | >C-C02C2H6, thick, colorless prisms fusing at 120-121°. When heated with 284 AROMATIC COMPOUNDS. concentrated sulphuric acid, it passes into indigo-sulphonic acid. The ethoxyindoxylic ethyl ester: OC2Hs C H C6H4/ | \CTC02C2H5, has been obtained in the form of large colorless crystals fusing at 98°. On saponifying indoxylic ethyl ester, indoxylic acid: OH C ? C6H4/ | \c~COOH, fusing at 122-123°, is formed. By the action of acid oxidizing agents, it is converted into indigo-blue. By boiling the ester with alcoholic baryta and acidifying, glittering leaflets of ethoxyindoxylic acid: OC2H5 A H c6h4/ | Nctcooh, \~vr/ fusing at 160°, are obtained. On warming with a solution of ferric chloride and HCl, it loses its ethyl group and is con- verted into indigo-blue. The ethoxyindoxylic acid behaves with nitrous acid like oxindole, yielding ethoxy-nitroso-indox- ylic acid: OC2H5 c6h4/ | Vtcooh, N NO in the form of golden-yellow needles. On reduction, it yields, DIACETYLENEPHENYL. 285 like oxindol, an amido-compound which gives on oxidation, isatin. Indoxylic acid when heated to fusion evolves C02, and affords an oil which is probably indoxyl: OH A C6H4< | >CH2 Ethoxyindoxylic acid, however, also evolves C02 on fusion, and yields an oil possessing the odor of indol, which is ethoxy- indoxyl: OC2H5 C6H4<' | ">CH2. Orthonitrophenylpropiolic acid is converted by boiling with water into orthonitrophenylacetylene. By exposing the latter in the form of its cuprous oxide compound to the action of an alkaline solution of potassium ferricyanide, it is changed into orthodinitrodiphenyldiacetylene: C6H4<^N"0g N0^C6H4, which is the dinitro-derivative of the hydrocarbon from which indoxyl is derived, viz., diacetylenephenyl: C6H5-C=C-C=C-C6H5. The dinitro-compound is converted by the action of cone. sulphuric acid into diisatogen, C]6H8N204, which by the action of reducing agents is changed into indigo-blue : C16H8N204 - 02 + H2 = C16H]0N2O2. The formation of indigo-blue from orthonitrophenylpro- 286 AROMATIC COMPOUNDS. piolic acid is, then, dependent on the formation of the inter- mediate compound, indoxyl : n tt /CEC_COOH °<>H±\N02 Orthonitrophenylpropiolic acid OH i C6H 4>-Indoxyl OH OH i C6H 4>,cfcHc'H'-1 Indigo-white -1-1 C6H /_02~\ The formation of indigo-blue from diisatogen is probably as follows : /0202N^ C6H4<( | >C-C CH-CH< | >C6H4. The constitution of the blue is more apparent when ex- pressed : N---CH'CH---N /\/ \/\ C6H4-C-0-0-C--C6H4. SUBSTITUTIONS OF BENZENE. 287 Attention has frequently been drawn to the easy substituti- bility of the hydrogen of benzene and its derivatives, by other elements and atomic groups. The ease with which the hy- drogen of benzene is replaced gives rise to a series of reactions which as yet have not received particular attention. On pass- ing benzene through a red-hot tube, diphenyl, C6H6~C6H6, (p. 204) is formed, i.e., an H of the benzene, is replaced by another benzene rest while hydrogen is set free. Phenol on C6H4_OH fusion with notassium hydroxide yields diphenol, \ : C6H4 OH 2 C6H5OH = C6H4(OH)-C6H4(OH) + H2, and hydrazobenzene, C6H5"NH"]SrH"C6H5, is converted by C H "NH acids into benzidine, ■ *■ 4 2 (p. 224). By the action of C6H4 NH2 methyl chloride, etc., on benzene in presence of aluminum chloride, chlorhydric acid is evolved, the chlorine of the methyl chloride unites with the hydrogen of the benzene, and methylbenzene, dimethylbenzene, etc., up to hexamethyl- benzene are formed (p. 275). When sulphuric acid is allowed to act on a mixture of ben- zene, phenol, etc., with an aldehyde, the oxygen of the alde- hyde unites with the hydrogen of the benzene, forming water and condensation products : CH3-CHO + 2 C6H6 = H20 + OH,-OH^g«g». Diphenyiethylid'ene Acid anhydrides also react on benzene arid its derivatives in presence of sulphuric acid, forming condensation products : CA° + 2 C«H*0H = C6H4^C0\0 (C6H4OH)8 Phenol phthale'in The phthaleins are produced by this method. The most 288 AROMATIC COMPOUNDS. interesting of these reactions is the condensation of a mixture of aniline and ortho- or paratoluidine or its homologues. Two hydrogen atoms of the methyl and 2 H's of the two benzene rests are oxidized to water, and a triamidoderivative of tri- phenylmethane is formed : O.H.NH, , 0 H //NH2_C6H4(NH2J\C<^>h, or its salts, pararosaniline (p. 259). This condensation and the consequent union of several ben- zene rests, either directly to each other or indirectly by means of methyl or ethyl rests, also takes place, as we have seen, by exposing benzene and its derivatives to a high heat. It is from this reason that diphenyl and other hydrocarbons which will be mentioned later, as naphthalene, anthracene, phenan- threne, chrysene, etc., exist in coal-tar. Among the condensation products which have not yet been mentioned C TT \ are fluorene, or diphenylenemethane, i 4 \CH2, which is found in coal- C6H4/ tar, and has also been produced synthetically. Itfuses at 113° and boils at 295°. Diphenylbenzene, CeHs'CeH^CeHs, which is formed by leading a mixture of benzene and phenol through a heated tube (f. p. 205°), and C H \ carbazol, i" ' J>NH, which is found in coal-tar. Lastly acridine, C6H4/ Cj2H9N, which is isomeric with carbazol. Retrospect. In reviewing the compounds derived from benzene, we are struck by the abundance of isomers which the higher substi- tuted benzenes yield, and also by the differences in the char- acteristic properties which exist between the substitution- products of the aromatic bodies and those of the fatty series. The aromatic chlorides, bromides, and iodides (so long as the halogen is not in the side-chain), are far more stable than their analogues in the fatty series. The hydroxyl derivatives are more stable than the alcohols, and in many relations re- semble acids. Sulphuric and nitric acids convert the aro- matic compounds with great ease into sulphonic acids (substi- tutions of the rest S02OH) or sulphones (the rest S02) and nitro-compounds (substitutions of the rest N02). The following is a list of the more important derivatives of benzene arranged in series. Hydroxyl Derivatives. 1. Monohydroxyl derivatives : C6H5(OH), Phenol. 2. Dihydroxyl derivatives : C6H4(OH)2, Resorcinol, Catechol, Quinol. 3. Trihydroxyl derivatives : C6H3(OH)3, Pyrogallol, Phloroglucinol. The third is not known, nor have any higher hydroxyl de- rivatives been obtained. 19 289 290 RETROSPECT. Carboxyl Derivatives. 1. Monocarboxylic acids : C6H5"C02H, Benzoic acid. 2. Dicarboxylic acids: i\ n tt i 1 C02H l) u6±i4 -j3 002H' n\ p n j 1 C02H A) ^6^4 | 3 C02H' 3) C6H4|4C0^H, Phthalic acid. Isophthalic acid. Terephthalic acid. 3. Tricarboxylic acids : C6H3(C02H)3 : 1) 1.2.3. Hemimellitic acid. 2) 1.2.4. Trimellitic acid. 3) 1.3.5. Trimesinic acid. 4. Tetracarboxylic acids : C6H2(C02H)4 : 1) Pyromellitic acid. 2) Phrenitic acid. 3) Mellophanic acid. 5. Pentacarboxylic acids : (unknown). 6. Hexacarboxylic acids : C6(C02H)6, Mellitic acid. In other series are : 1. Phenylformic acid.: C6H5 C02H, Benzoic acid. 2. Phenylacetic acid : C6Hg~CH2C02H, Alphatoluic acid. 3. Phenylglycollie acid : C6H5"CH(OH)C02H, Mandelic acid. HYDROCARBONS. 291 4. Phenylpropionic acid : ®g^5 CH2 CH2~C02H, Hydrocinnamic acid. 5. Phenylacrylic acid: C6H5~CH=CH~C02H, Cinnamic acid. Hydrocarbons. 1. 2. 3. Benzene, CftH, B. '•I ■I 9 10. 11. 12. 13. 14. •I Methylbenzene, toluene, C6HgCH3 = C,H8, Ethylbenzene, C6H5"C2H5 = C8H10, Propylbenzene, C6H5"C3H, = C9H12, Isopropylbenzene, cumene, C6H5"C3H,, Butylbenzene, C6H5"C4H9 = C10H14, Isobutylbenzene, C6H5~C4H9, Amylbenzene, C6H5~G51L11 = G11H16, Dimethylbenzene, xylene, C6H4(CH3)2 = C8H10, Methylethylbenzene, C6H5(C2H5)(CH3), Methylpropylbenzene, cymene, C6H4(CH3)(C3H,) = C9H12, Diethylbenzene, C6H4(C2HS)2 = C10H14, Methylamylbenzene, C6H4(CH3)(C5H11) = C12H18, Trimethylbenzene,* C6H3(CH3)3 = C9H12, Dimethylethylbenzene, ethylxylene, C6H3(CH3)2(C2Hg) = C10H14, Dimethylamylbenzene, amylxylene, C6H3(CH3)2C5H11 =C13H20, 82°. 111°. 134°. 157°. 151°. 180°. 167°. 193°. 140°. 160°. 175°. 178°. 213°. 166°. 184°. 233°. * Mesitylene and the pseudocumene of coal-tar. Naphthalene. There is found in coal-tar, besides benzene and its methyl- substitutions, a very large amount of another hydrocarbon which is always formed when organic substances, even of the simplest constitution, as alcohol, acetic acid, etc., are exposed to a red heat in the absence of air. This body is naphthalene, C10H8, a derivative of benzene, and of the following con- stitution : CH=CH_C~CH=CH CH=CH"C"CH=CH It is a benzene nucleus in which two adjacent hydrogen atoms are replaced by the divalent hydrocarbon rest, C4H4, or -CH=CH_CH=CH". This hydrocarbon rest is a part of a benzene ring which, when attached to another benzene ring, produces a double ring. The formula of naphthalene is represented by a double benzene nucleus, or it might be said by two benzene rings welded together. We see at once that naphthalene is capable of yielding an immense number of substitutions, and that the number of isomeric derivatives must be greater than in the case of benzene. We shall only take up a few of the more important derivatives. Naphthalene yields two series of mono-substitutions depend- 292 H H HC C CH HC 0 CH No/No' H H SUBSTITUTIONS OF NAPHTHALENE. 293 ing on whether the hydrogen atom which is replaced is ad- jacent or not to the carbon atoms which do not bind hydrogen. If the substituting element be represented by X, the constitu- tion of the two isomers will be : H X H H >C6H4. Chlorine converts anthracene into anthracene dichloride, Ci4HioCl2. With bromine a compound is formed which is both an addition- and sub- stitution-product, dibromanthracene-tetrabromide, Ci4H»Br2. Br4. With carbonyl chloride, COCl2 (p. 35), anthracene yields anthracene-carboxylic acid, C14H0CO2H. C]4H10 + COCl2 + H20 = C14H9(C02H) -f 2 HCl. The quinone of anthracene, anthraquinone. and its derivatives, are the most important compounds of the anthracene series. When anthracene is heated with nitric acid, anthraquinone : Lerl4<( y-,Q ^CeH4, is produced. It forms crystals fusing at 277°. Anthraquinone forms, when treated with sulphuric acid, anthraqui- nondisulphonic acid, Ci4H702(S03H). The potassium or sodium salt of this acid yields, when fused with potassium hydroxide, dioxyanthraqui- none, or alizarin, Ci4H6(OH)202 = C14Hc04. The same reaction takes place with the dibromanthraquinone. Alizarin, C14H804, like indigo-blue, is a coloring matter which does not occur already formed in plants, but is produced from a glucoside contained in them by a species of fermenta- tion. In the root of the madder (Rubia tinctorium) a sub- stance occurs which is called ruberythric acid, C26H28014. By the action of ferments, or by boiling with dilute acids or alkalis, it falls into glucose and alizarin : C26H88014 + 2 H20 = 2 C6H1206 + C14H804. Alizarin crystallizes in yellowish-red prisms containing ALIZARIN. 303 3 H20. At 100°, it loses its water of crystallization, turning red, and at a stronger heat, sublimes in red needles. It is .insoluble in water, and difficultly in alcohol and ether, with a yellow color. It is easily soluble in alkalis, with a purplish red color, the solution showing a fine fluorescence. Concen- trated sulphuric acid dissolves it without change, forming a red solution which is precipitated by water. Nascent hydro- gen converts it into hydroalizarin, C14H1004, and nitric acid into a nitro-derivative. Alizarin has decided acid properties, and unites with bases. To this property it owes its solubility in alkalis. Its com- pounds with the alkaline earths, alumina and iron oxides, are insoluble. Alizarin, is therefore, precipitated from its solu- tion in alkalis by these substances. In turkey-red dyeing, the alumina compound of alizarin is formed by passing the cloth saturated (mordanted) with an alum solution through a solu- tion of alizarin, the insoluble compound being thus produced directly on the fibre. On heating with zinc dust, alizarin is reduced to anthra- cene. On heating nitroalizarin with glycerol and sulphuric acid, a peculiar reduction takes place with the formation of "alizarin-blue. " C14H,04(N02) + C3Hb03 = C17HION04 + 3 H20 + 03. The constitution of this compound is : Cfl==CH CH=CH-C-CO-C-C=C-N=CH CH=CH-C-CO-C-C=C_OH OH Besides alizarin, madder roots contain an oxidized alizarin which has been gradually formed from the alizarin by the action of the oxygen of the air. It is called purpurin: C14H6(OH3)302 = C14H805. 504 CHRYSENE. It is also produced as a side-product in the manufacture of artificial alizarin. Purpurin is soluble in water and alkalis. Its alumina compound is also soluble. It dyes wool, etc., a color resembling that given by alizarin. In the artificial production of alizarin, there are also two acids obtained which are isomeric with alizarin, viz., anthra- fiavic acid, forming yellow silky needles fusing; above 330°, and isanthraflavic acid, also forming yellow needles fusing at 330°, but crystallizing with one molecule of H20. From the bark of a species of alder (Rhamnus frangula) a glucoside, frangulin, C20H20O10, is obtained, which on boil- ing with acids breaks into dextrose and Frangulic acid, C14H804, which is isomeric with alizarin. It forms crystalline needles containing \ molecule H20, and fuses at 252°. Besides the above mentioned dioxyanthraquinones, there are quinazarin, yellowish-red leaflets fusing at 195°, purpur- oxanthin, yellowish-red needles fusing at 262°, and chrysazin, leaflets fusing at 191°. Compounds isomeric with purpurin are also known, viz., anthrapurpurin, C14H805, orange leaflets fusing over 330°, and flavopurpurin, long, golden-yellow needles. Higher hydroxylated anthraquinones are also known. An- thrachrysone, C14H806, golden-yellow, fine needles; rufiopin, C14H806, golden-yellow needles ; rufigallic acid: C14H808 + 2H20, small, glittering, brownish-red needles. The roots of the rhubarb contain a yellow dye-stuff called chrysophanic acid, C15H10O4. It does not exist already formed in the plant, but is produced by a species of fermen- tation from a glucoside, chrysophan, C2,H30O14, which breaks into dextrose and the coloring matter. Chrysene, Ct 8HX 2 (p. 300), exists in coal tar, from which it CAMPHOR GROUP. 305 distils at a red heat. It crystallizes in colorless leaflets, fusing at 250°. It is usually more or less yellow. Chlorine, bro- mine, and nitric acid convert it into substitution products. Chromic acid oxidizes it to chrysoquinone, C18H10O2, which can be converted into chrysoquinol, C18H10(OH)2, dichlor- chrysoquinone, C18H8C1202, and per chlor chrysoquinone, C18C11002. Another hydrocarbon, retene, C18H18, is also found in coal-tar. It forms mother-of-pearl leaflets fusing at 98°. Among the other constituents of coal-tar, arefluoranthrene, C15H10, leaflets fusing at 109°, andpyrene, C16H10. Both of them yield chlorine, bromine and nitro-derivatives, as well as the quinones and their derivatives. The constitution of fluoranthrene is probably : /C6H~CH CH2< 3 i. , , 2\C6H3-CH' and that of pyrene : CH"C6H3"CH CH"C6H3"CH ' In lignite coal-tar, a hydrocarbon, picene, C22H14, has been found, which crystallizes in colorless leaflets. Following the compounds which we have so far considered, there are several groups of bodies, the constitution of which has either not yet been determined, or does not allow of their consideration in the groups already treated of, without sepa- rating bodies which are really closely related. Camphor Group. In the cavities in old stems of a species of trees growing on the islands of Sumatra and Borneo {Dryobalanops camphora), 20 306 CAMPHOR. a body is found, which is known as Borneo-camphor, or Borneol, C10H18O. It is crystalline, fuses at 198°, and boils at 212°. It has a burning taste and the peculiar odor of camphor. It is insoluble in water, and turns the plane of polarized light to the right. With chlorhydric acid, it yields a chloride, C]0H]7C1, and Avith other acids, ether-like derivatives are formed. Nitric acid converts it into ordinary camphor. Camphor, Cj 0Hj 60, is found in the camphor-tree, which is indigenous to China and Japan. It forms white, translucent masses Avith a peculiar odor and a burning taste. It fuses at 175° and boils at 205°. It can be cut with a knife, but is difficult to pulverize. This is accomplished more easily, Iioav- ever, when moistened with alcohol. It is insoluble in Avater, and soluble in alcohol, ether, acetic acid, concentrated sul- phuric and chlorhydric acids. Small particles of it when thrown on water swim on the surface with a rotary motion. It burns, on heating, with a smoky flame. Its alcoholic solu- tion turns the plane of polarized light to the right. It unites with bromine, forming an addition-product, Cj 0Hj 6Br20, which on distillation loses bromine, and is con- verted into monobromcamphor. Dehydrating agents, as phos- phoric anhydride, zinc chloride, etc., convert it into cymene, (methylpropylbenzene), attacking it, however, more vitally and forming at the same time methylbenzene (toluene), dimethyl- benzene (xylene), and trimethylbenzene (pseudocumene). On digestion with potassa at 300°, it is changed into cam- pholic acid, Gli)Tl1802 : °i 0Hi 60 + HgO = Ct oil, 802. By boiling a considerable time with nitric acid, it is converted into camphoric acid, Gt 0Hj 604. By the action of sodium, it is changed into Borneo-camphor, C10H18O. The sodium compound of both Borneo-camphor and ordinary camphor is first formed : CAMPHOR. 307 2 C, 0H, 60 + Na2 = C, 0Ht ,NaO + C, 0H, 5NaO. The former being converted by the action of carbonic acid and water into Borneo-camphor. C, 0H, ,NaO + C02 + H20 = C10Ht 80 + NaHC03. Calcium camphorate, on distillation, is converted into a compound isomeric with phoron, C9H,40 (see later), which by oxidation breaks into acetic acid, C2H402, adipinic acid, C0Hi„O4, and carbonic acid : CaH140 + 70 = C2H402 + C6H1004 + C02. By heating Avith iodine, camphor is converted into cumic phenol : C10H13-OH = C6H4(C3H,)-CH2OH, a thick oil isomeric with thymol. Prom the above facts the constitution of camphor and its derivatives is most probably as follows : Camphor contains a reduced benzene nucleus with a methyl and a propyl group : C3H7 I CH H2C CH2 HC CO Y CH3 Prom which are derived : C3H7 C3H7 C3H7 CH CH CH H2CCH2 H2C CH3 H2C COOH HC CH(OH) HC COOH , H(i COOH Y Y Y CH3 CH3 CH3 Borneo-camphor Campholic acid Camphoric acid 308 ESSENTIAL OILS. Several bodies are known which are isomeric with camphor. There are also a large number of substances resembling camphor, of which we shall only mention the following : Peppermint-camphor, or menthol, Ci0H20O, separates from peppermint- oil. It fuses at 42° and boils at 212°, and has the odor and taste of pep- permint-oil. Elecampane-camphor, Ci0H16O, is contained in the roots of the Inula helenium. It fuses at 64°. Helenine, Ci2Hi602, occurs with it forming needles fusing at 110°. The young stems of the dryabalanops, from which Borneo-camphor is obtained, yield also a hydrocarbon, C,0Hi6, camphor-oil, from which Borneo-camphor seems to be formed after a time. Essential Oils, There are a very large number of substances which have the composition C10H16. They are called essential oils, and occur in plants, being obtained by distilling them with steam. We shall only mention the more important ones. Their con- stitution is not known with certainty. In general we understand under essential oils, a number of plant-prin- ciples which boil without decomposition, are all indifferent, possess strong odors and burning tastes, are nearly insoluble in water, are mostly liquid and seldom solid at ordinary temperatures, and differ from the fatty oils (glycerides) by their volatility and odors. They are divided into 1) Essential oils free from oxygen. These are the essential oils proper. They nearly all possess the composition Gt 0H16 (or a multiple of it), are lighter than Avater, turn the plane of polarized light, and are converted into terephthalic acid by oxidizing agents. In this class belong turpentine-oil, lemon-oil, orange-peel-oil, cubeb-oil, cardamon-oil, savin-oil, bergamot-oil, cajeput-oil, lavender-oil, rosemary-oil, and amber-oil. 2) Essential oils containing oxygen. TURPEN TINE-OIL. 309 a) Mixtures of oils containing oxygen with oils free from oxygen : Valerian-oil, flag-oil, caraway-oil, nutmeg-oil, clove- oil, thyme-oil, parsley-oil, ivormioood-oil, rue-oil, curled- mint-oil, peppermint-oil, and rose-oil. b) Oils containing oxygen : Bitter almond-oil, cinnamon-oil, anise-oil, fennel-oil, marjo- ram-oil, camomile-oil, sage-oil, and tansy-oil. 3) Oils containing sulphur : Mustard-oil, spoonwort-oil, and leek-oil. Turpentine-Oil, Ci0Hi6. Turpentine-oil is the representative of all of the essential oils free from oxygen. Most of its reactions resemble those of the other essential oils of this class. When incisions are made in the bark of trees belonging to the abietinem family, a thick sap flows out, which is called turpentine, and is a mixture of rosin and turpentine-oil. By distilling with steam, this product yields turpentine-oil. It is a colorless liquid with a peculiar and disagreeable odor. It boils at 160°, and is lighter than water (sp. gr. 0.86). It is insoluble in water, although it imparts its odor to it. In alcohol, ether, and acetic acid it is soluble. Phosphorus, sul- phur, resins, and caoutchouc dissolve in it, and it is hence used in the preparation of resin and oil varnishes. It turns the plane of polarized light, the various kinds having different powers of rotation, by which they can be distinguished. The German oil, from Pinus sylvestris and Abies excelsa, the French oil, from Pinus maritima, and the Venetian oil, from Larix Europe, polarize to the left, the English oil, from Pinus australis polarizes to the right. Concentrated sulphuric acid converts all the different kinds of turpentine-oil into inactive turpentine, or camphene. Turpentine-oil takes up oxygen from the air, and becomes thick and resinous. The oxygen absorbed shows all the prop- erties of ozone. With strong oxidizing agents, as fuming nitric acid, the oil ignites. On standing some time Avith water, it takes up two mole- 310 TERPENE DIBROMIDE. cules, and changes into a crystalline substance, terpin, C10H20O2, which crystallizes with one molecule of water, becomes anhydrous at 100°, fuses at 103°, and sublimes in needles. By leading chlorhydric acid gas into an alcoholic solution of turpentine-oil, they unite, the latter taking up two molecules of HCl, and forming the compound Gi qHj ,C12, terpene dihydro- chloride. When the chlorhydric acid is passed into dry turpen- tine-oil, the compound C10H17C1, terpene monohydrochloride, is produced. This is isomeric with borneol chloride, and exists in a liquid and a solid modification. On boiling Avith dilute nitric acid, it is Aritally decomposed, with the formation of cyanhydric, formic, acetic, propionic, butyric, terephthalic, and terebic acids. Terebic Acid, C,H10O, has probably the constitution : j<23^>CH-CH-C00H 6—CO Terpene Dibromide, C10H16Br2, which is formed by the action of bromine, loses 2 HBr on heating, yielding cymene (methylpropylbenzene). The production of terephthalic acid and cymene proves that terpene contains the benzene nucleus. By repeated distillations, as well as by treatment with various acids, turpentine-oil is converted into the inactive camphene, CioHio, which is a crystalline mass, fusing at 58° and boiling at 160°. Lemon-oil, Ci0Hi6, is obtained by pressing lemon-skins. It is lighter than water, boils at 175°, and has the odor of lemons. It unites with 2 HCl. Among the oils containing oxygen we shall mention Valerian-oil, which is obtained from the roots of the valerian. It is a mixture of valerianic acid, C6Hi002, valerene, Ci0Hi6, and valerianic est- ers ; its components can be separated by fractional distillation. Caraway-oil, is contained in the seeds of the Carum ca/rui. It contains a hydrocarbon, Ci0Hi6, and carvol, Ci0Hi4O. Soman caraway-oil is produced from the Cuminum cyminium. It is mixture of cymene, CioHn, with cumic aldehyde, Ci0Hi4O. Clove-oil is obtained from cloves by distillation with steam. It is a RESINS. 311 mixture of a solid hydrocarbon, C2oH32, which boils at 254°, vrith eugenol, CioHi202. Eugenol is an oily liquid boiling at 247°, which by fusion with potassium hydroxide is decomposed into protocatechuic and acetic acids. (OH Its constitution is, C6H3 \ OCH3. Eugenol is the monomethyl ether of (C3H5 allylpyrocatechol, and stands in intimate relation to coniferyl alcohol, (OH C6H3 \ OCH3 (compare glucosides), and to ferulic acid, ( C3H4"OH (OH C„H3 \ OCH3 ( C3H2C02H which exists in asafcetida. Thyme-oil, from Thymus vulgaris, consists of a hydrocarbon, Ci0H16, thymene, and thymol, the phenol of a-cymene. Parsley-oil, contains a hydrocarbon, Ci0Hi6, and the so-called parsley- camphor, Ci2Hi40. Wormwood-oil, from Artemesia absynthium, is a dark-green oil, which contains a hydrocarbon, CioHie, a body isomeric with camphor, doHi60, and a blue hydrocarbon, probably C20H42, boiling at about 290°. Rose oil is a mixture of solid hydrocarbons, Ci6H34, with an oxygenated substance which has not been fully examined. Anise-oil and Fennel-oil contain anethol, Ci0Hi2O, as their chief con- stituent. It fuses at 21° and boils at 232°, and by oxidation is converted into anise-aldehyde and anisic acid. Its constitution is C0H4 ] r; tt 3. Bitter Almond-oil contains benzaldehyde, C6H5-CHO, and cyanhydric acid. Cinnamon-oil, consists of cinnamic aldehyde, C6H5~CH=CH~CHO. Wo have already met with a representative of the sulphuretted oils in mustard oil, C3H6NCS, and leek-oil (allyl sulphide) (C3H6)S2. Spoon- wort-oil is the mustard-oil of the secondary butyl alcohol, C4H9NCS. Resins. The resins are obtained, together with the essential oils, from plants. They are either dissohred in the essential oils, in which case they are called balsams, or are mixed with gum, being then known as resins. As the essential oils take up 312 RESINS. —B A LSAMS. oxygen on standing, becoming more consistent, the balsams on exposure gradually become hard. The resins are mostly amorphous, brittle bodies, which are insoluble in water and soluble in alcohol, ether, fatty, and essential oils. They are fusible, but decompose at a higher temperature. They exhibit acid properties. Turpentine contains, besides turpentine-oil, a resin called colophony, rosin, or ordinary resin, which consists chiefly of sylvic acid, C44H6405, and an isomeric amorphous acid, pinic acid. Copaiba balsam contains copaiba-resin, which consists chiefly of copaibic acid, C20H30O2. It forms trans- parent, colorless crystals. Quaiacum resin, from guaiacum officinalis, forms reddish-brown spherical masses which, when exposed to the air, or treated with chlorhydric acid, are col- ored green. Its alcoholic solution is colored dark-blue by nitrous acid and ozone. Shellac is easily soluble in alcohol and alkalis, and is used in the preparation of varnishes and sealing-wax. Balsam of Peru contains, besides the resin, cin- namic acid, cinnamein (cinnamic benzyl ester, p. 272), and styracin (cinnamic cinnyl ester, p. 272). Storax contains, be- sides a resin, styracin as chief constituent, and also cinnamic acid and styrene, C8H8. Balsam of Tolu contains various resins, benzoic acid, and an essential oil boiling at 170°. Benzoin resin, serves as the source of benzoic acid, containing 18 io of it. Aloes, from A loe capensis is a deep brown, or when made from Aloe succotrina, a reddish-brown amorphous mass, which on treatment with water yields aloi'n (see later). Jalap is a yellowish-brown mass. Mastic forms bright-yellow grains with a balsamic odor and taste. Gum Ammoniac is the dried milky sap of the Dorema am- moniacum, and forms yellow to yellowish-brown grains, which on fusion Avith potassium hydroxide yield, besides volatile fat acids and oxalic acid, resorcinol. Gum galbanum is the dried milky sap of the Ferula erubescens. Asafcetida is the dried milky sap of the Scorodosma fcetidum, and is an offensively PYRIDINE BASES. 313 smelling brownish resin, which owes its odor to a sulphuretted oil, C12H22S2, boiling at 135°. On fusion with potassium hydroxide, it yields, besides volatile fatty acids, protocatechuic acid and resorcinol. Euphorbium is obtained from Euphorbia resinifera. Its active constituent is euphorbon, which is the anhydride of an acid not yet thoroughly examined. Among the remaining gums are gum-elimi, frankincense, and myrrh. Caoutchouc is intimately related to the resins. Many trees, especially those of the euphorbiaceaz, yield a juice, when incisions are made in them, that gradually hardens in the air to an elastic mass. Its composition corresponds to the formula CgHj 4. When caoutchouc is heated with sulphur, it becomes " vulcanized," and is then much more elastic and does not be- come brittle when cold. On heating higher, it is converted into a peculiar substance known as "vulcanite," or hard rubber. A substance very similar to caoutchouc occurs in the East Indies, which is known as gutta percha, and has the composi- tion C10H16. It is produced by a tree belonging to the sapodilla family, and is obtained in the same way as caout- chouc. To conclude, we shall mention the fossil resins, amber and asphalt. The former is found on the coast of the Baltic Sea, contains a resin, amber oil, and succinic acid. The latter has probably been formed from petroleum, and is a black mass fusing about 100°. Pyridine Bases. There are several nitrogeneous substances which have the same composition as aniline and its homologues, but which are different from them. They do not contain the benzene nucleus, and the lowest member of the series has less than six carbon atoms. They occur in coal-tar and in animal oil (Dip- 314 PYRIDINE BASES. pel's oil), and are formed by the decomposition of the alka- loids. Some of them have been produced artifically. The nitrogen in them is bound to the carbon by three bonds, so that they may be considered as nitrile-bases, while aniline and its homologues are amido-bases. At present there are known Pyridine, C5HeN Picoline, C6H,N Methylpyridine, (isomeric with aniline) Lutidine, C,H9N Dimethypyridine, (isomeric with toluidine) Collidine, C8H^N Trimethylpyridine, (isomeric with xylidine) Parvoline, C9H13N Tetramethylpyridinc, (isomeric with cumidine) Picoline and collidine have been produced artificially. Picoline is formed by heating the comnound of aerole'in-ammonia, 2 C3H40 . NH3: C6HB02. NH3 = C„H7N + 2 H20. Picoline is also obtained by heating allyl tribromide, C3H5Br3, with ammonia : 2 C^Br-, + NH3 = C6H7N + 6 HBr. The reaction takes place in two steps. At first, dibromallylamine, C3H4Br) C3H4Br >-N, is formed, which then yields picoline by the elimination of H ) 2 HBr. We can therefore easily understand the constitution of picoline. C3H4Br) C3H4\ C3H4Br [ N, gives . >N, or H) C3H4/ CH=CH_CH CH=C_N CH3 Pyridine is, hence, constituted analogously to benzene PYRIDINE BASES. 315 A 11 i HC CH w i.e. it is a benzene-ring in which a CH-group is replaced by an N. The other bases of this series are homologues of pyridine, picoline being methylpyridine, etc. Ethylidene chloride and ammonia yield collidine : 4 CH3-CHC12 + NH3 = C8H16N + 8 HCl. All of these substances are liquid, and have a peculiar and penetrating odor and a bitter taste. They are volatile without decomposition, and possess basic properties, i.e. they unite like ammonia directly with acids to form salts. The lower mem- bers are miscible with water, the higher ones are soluble in it. The isomeric relations which exist in the benzene derivatives, also appear in the pyridine derivatives. From the formula of pyridine we see that there are three methylpyri- dines (picolines) possible (they are all three known). The number of isomers in the higher homologues is, of course, greater. The pyridine bases have lately acquired a greater interest, as they have been found to constitute the basis of the more important alkaloids. By oxidation of pyridine as well as of the alkaloids, pyridine-carboxylic acids, C5H4N"C02H, C5H3N(C02H)2, etc., are formed. There are a number of other bases found in coal-tar, which are related to the pyridine bases, viz. : Quinoline, G 9 H, N Lepidine, G10 H 9 N Cryptidine, G11H11N. They are obtained by the decomposition of quinine, strych- 316 PYRIDINE BASES. nine, etc. Quinoline stands to pyridine in the same relation as naphthalene to benzene : Pyridine : Quinoline: H H H HC CH HC C CH HC CH HC C CH H We see from the above figure that in the quinoline bases the nitrogen has no replaceable hydrogen. They are oils insoluble in water. Quinoline is produced synthetically when nitrobenzene or aniline is heated with glycerol and sulphuric acid : C6H5N02+C3H803 = C9H,N + H20 + 02 C6H5NH2 + C3H803 = C9H7N + H20 + H2. A similar constitution may be ascribed to another class of bodies whose chief representative is pyrrole, C4H6N, which is obtained by the dry dis- tillation of nitrogenous substances (coal, bones, etc.). Pyrrole is a color- less liquid with an odor like chloroform. It is insoluble in water and soluble in acids. It is, however, not properly a base, for it can be entirely removed from its solution in an acid by boiling. It colors a splinter of pine, moistened with chlorhydric acid, purplish-red, and may be thus detected. Pyrrole acquires easily a brown color, and an amorphous red substance separates, which is called pyrrole-red, Ci2Hi4N30, The constitution of pyrrole is probably CH=CH\ CH=CH >NH. It is also formed by the distillation of ammonium mucate : CBH90B-NII., = C,Hr,N + 2 C02 + 4 H20. By the distillation of mucic acid by itself, pyromucic acid, C5H403, is ALKALOIDS. 317 obtained. This acid is also formed by boiling furfurole with moist silver oxide. It is a monobasic acid. Its ammonium salt yields pyrrole on heating. Its constitution is perhaps : COOH CH"C\ ii i >0 CH"C/ i H On distilling pyromucic acid with an excess of soda-lime, carbonic acid splits off, and tetrol, or tetraphenol, C4H40, is obtained. It is a colorless liquid boiling at 32°, and has a peculiar odor. The aldehyde of pyromucic acid is known under the name furfurole, C5H40. It is obtained by the distillation of clover, meal, sawdust, etc. with dilute sulphuric acid. It unites with the acid sulphites of the alkalis, and, on boiling with silver oxide, is converted into pyromucic acid. Its constitution is hence : CHO CH=C\ i >0 CH=C/ i H Alkaloids. We now come to a large class of very important nitrogenous substances which occur in many plants, and which, on ac- count of their energetic action on the organism, have numerous uses. They all possess basic properties, and are hence called in a limited sense, organic bases, or alkaloids. Their consti- tution is in most cases not yet understood, but the majority of them seem to be derivatives of the pyridine bases. The alkaloids are all practically insoluble in water, but give soluble salts with acids. They are set free from the solutions of their salts by alkalis' and alkaline carbonates, being precipi- tated as free alkaloids. Tartaric acid hinders the precipita- tion of the alkaloids with the exception of strychnine, narco- 318 ALKALOIDS. tine and cinchonine. They are all soluble in alcohol, but not all in ether. They are precipitated from solutions of their salts by tannic acid, potassium mercuric iodide, potassium cadmium iodide, phosphomolybdic acid, phosphotungstic acid, and metatungstic acid. They are obtained by extracting the pulverized plants with acidified water, and when the alkaloid is volatile, distilling, after the addition of an alkali. If the base is not volatile, which is generally the case, the base is precipitated with an alkali. The precipitated alkaloid is purified by again dissolving in an acid, recrystallizing the salt, and reprecipitation by an alkali. Some alkaloids contain only carbon, hydrogen, and nitrogen, while others also contain oxygen. The former are liquid at ordinary temperatures, the others mostly solid and crystal- line. Conine, C8Ht 5N, exists already formed in the hemlock (Co- nium maculatum), and is obtained from the seeds by distilla- tion with Avater. It is a colorless liquid with a stupefying odor, boiling at 168°. It possesses extremely poisonous prop- erties. It dissolves in 100 parts of water, and in the cold dissolves some Avater, but not when warm. Moist conine for this reason becomes turbid when warmed, even the warmth of the hand affecting it. Its aqueous solution reacts strongly alkaline, and completely neutralizes strong acids. It becomes brown and thick when exposed to the light, decomposing with evolution of ammonia. Oxidizing agents convert it into butyric acid, C4H802. It coagulates a solution of albumin. Dry chlorhydric acid gas colors it at first purplish-red and then deep blue. It absorbs nitrous acid gas. Conine saturated with nitrous acid gas, when treated with water, yields azoconhydrine, C8Hi0N2O, which separates as a bright-yellow oil, and by the action of phosphoric anhydride is converted into water, nitrogen, and conylene, CHH14. Conine has not yet been produced artificially, but a com- NICOTINE. 319 pound isomeric with it and resembling it very much, paraco- nine, is obtained by the action of ammonia on butylaldehyde. Normal butyl aldehyde unites with two molecules of ammonia, form- ing C4HbO . NH3 and CeH, c02. NH3. The latter yields on dry distillation paraconine, water being eliminated : CBH10O2. NH3 = C„H15N -f 2 H20. The compound, C8Hi602. NH3, dibutyraldine, possesses the constitu- tion : ch3-ch2-ch2-ch/oh >NH. ch3-ch2-ch2-ch/oh The constitution of paraconine is probably : CH3-CH2-CII=CH\M CHrcHrcHrcH/^- Conine is an amido-base. The H of the NH-group can be replaced by hydrocarbon rests (CH3, C2H5, etc.) and the re- sulting bases unite with acids, forming salts, and with chlo- rides, bromides, etc., producing ammonium compounds. Standing between conine and dibutyraldine, is conhydrine, C8H17NO, which is also contained in the seeds of the hem- lock. It crystallizes in mother-of-pearl leaflets fusing at 121° and boiling at 240°. It possesses weak basic properties. Nicotine, C10Hl4N2. This base is found in the leaves of the tobacco, and is obtained from them by extraction with dilute sulphuric acid. The different kinds of tobacco con- tain varying amounts of nicotine, ordinary tobacco containing from 7-8$, while the finest Havana tobacco contains less than 2$. Nicotine is a colorless liquid with a penetrating odor of tobacco and a burning taste. It boils at 250° with partial decomposition. It is easily soluble in water, alcohol, and ether. On exposure to the air it turns brown. It is very poisonous. It is a di-valent tertiary base, its nitrogen con- taining, therefore, no substitutable hydrogen. 320 ALKALOIDS. On oxidation it is converted" into nicotinic acid (pyridm- carboxylic acid), C6H5N02 = C6H4N"COOH. This acid fuses at 224°, and crystallizes in needles. Its constitution is unknown. Sparteine, C, 5H2 6N2, occurs in Spartium scoparium. It is a thick, colorless oil with a bitter taste, and boils at 288°. It is a di-valent tertiary base. The constitutions of the alkaloids containing oxygen are very complicated, and have been still less investigated than the preceding. In a few, it has been proved that the oxygen exists in the form of hydroxyl or CO. Opium Bases. By making incisions in the green seed-cap- sules of the poppy (Papaver somniferum) a white, milky sap is obtained, which, when dried, constitutes opium. Opium con- tains a large number of alkaloids, of which we can consider but a few of the more prominent. The most important alkaloid in opium is morphine, and the value of the opium is estimated by the amount of this base that it contains. Opium bases : Morphine CnHi9N03 Codeine C18H21N03 Codamine C20H23NO4 Laudanine C20H25NO4 Pseudomorphine CnH,9N04 Thebaine ^Mn^ isomeric Thebenine C19H21N03j Protopine C20H,9NO5 Papaverine C2iH2iN04 Deuteropine C2oH2,N05 Cryptopine C2iH23N05 Meconidine C21H23N04 Laudanosine C2)H27N04 Rhoeadine C21H21NO«,) isomeric Rhoeagenine (J21H 21JN U6) Narcotine C22H23N07 Narceine C23H29N09 [rine 7) Lanthopine C23H25N04 (homologous-with papave- Morphine, Gt ,11,9N03. On boiling opium with water, the OPIUM BASES. 321 morphine goes into solution in combination with certain acids (particularly meconic acid). From this solution, it is pre- cipitated, after neutralizing a part of the acids Avith milk of lime, by ammonium chloride. Morphine is precipitated by a solution of lime, but is redissolved by an excess. It behaves in the same manner with alkalis. In ammonia, how- ever it is insoluble. In cold Avater and ether it is almost insoluble. It dissolves in 500 parts of boiling water and in 40 parts of alcohol. It crystallizes in glittering, colorless, rhombic crystals containing a molecule of water, which it loses on fusion. On stronger heating, it carbonizes. A solution of morphine turns the ray of polarized light to the left. It is a strong base, and its salts are soluble in alcohol and water. The hydrochloride, 0, 7H, 9N03 . HCl + 3 H20, ace- tate, C17H19N03C2 . H402 -f-H20, and sulphate, (C17H19N03)2.H2S04 + 5H20, are worthy of mention. They all crystallize in fine needles. Morphine salts, when treated Avith nitric acid, turn first red and then yellow. Ferric chloride colors them deep blue. A solution of morphine in a little concentrated sulphuric acid is colored violet on the addition of sulphuric acid containing nitric acid. The nitrogen in morphine does not bind any substitutable hydrogen. It is hence a nitrile base. By heating morphine a considerable time with fuming chlor- hydric acid, it is converted into apomorphine, C17H17N02. Apomorphine is a white powder which, on exposure to the air, becomes quickly colored green. It is a powerful emetic. Codeine, C18H21N03, is homologous with morphine. It crystallizes with one molecule of water, is somewhat soluble in 21 322 ALKALOIDS. water, and fuses at 150°. At a higher temperature it is decomposed. Chlorine, bromine, and iodine yield substitu- tion products. It is also a nitrile base. Narcotine, C22H2-3N07, crystallizes in rhombic prisms fus- ing at 176°. It is almost insoluble in water, easily soluble in alcohol and ether. It is a weak base, its salts being decom- posed by boiling with water. On heating with chlor-, or iodohydric acid, narcotine loses successively three methyl-groups. On heating with water, it breaks into cotarnine, Ci2H,3N03, and meconine, CinHi0O4, and by heating with dilute nitric acid, into cotarnine, opianic acid, Ci0Hi0O5, and hemipinic acid, CioHioOa : C22H23N07 = C12H13N03 + C10Hio04, C„HMNOT + O = C,2H13N03 + CioH,„05, etc. Hemipinic acid is decomposed by iodohydric acid into methyl iodide, carbonic acid, and protocatechuic acid, C7H604 : C,oH,00« + 2 HI = 2 CHJ + C02 + C7H„04. The constitution of hemipinic- acid is, C0H2(CO2H)2(OCH3)2. -f H,0, is formed by the neutralization of an alcoholic quinine solution, with valerianic acid. Col- orless crystals with a bitter taste and the odor of valerianic acid. Quinine Tannate, is a yellow amorphous precipitate produced by adding a solution of tannic acid to solutions of quinine salts. It has a peculiar odor and a bitter astringent taste. It is almost insoluble in water and vary difficultly in alcohol. Quinine is a nitrile base. It polarizes to the left. When heated with potassa-lye it yields quinoline and its homologues, 324 ALKALOIDS. which are isomeric, but not identical, with those obtained from coal-tar and Dippel's-oil. By oxidation with potassium permanganate, pyridin-tricar- boxylic acid is obtained, C8H5N06 = CsH2N(C02H)3, which on heating breaks into carbonic acid and pyridin-dicarboxylic acid, C7H3N04, fusing at 254°. Quinine is used in medicine as an antifebrile agent. The green color which it forms with ammonia and chlorine Avater is characteristic of it. In most cinchona barks, there is found besides quinine, Cinchonine, Ci9H22N20, which has properties similar to those of quinine, although it is not so strong an antifebrile. It forms white, glittering, odorless prisms, with a bitter taste, which at first is hardly perceptible. It is difficultly soluble in water. On oxidation, it yields cinchoninic acid (quinoline-car- boxylic acid), C8N5H06, and pyridine-tricarboxylic acid, C8N5N06. The following salt is worthy of mention : Cinchonine Sulphate, (C19H22N20)2 . H2S04 -f 2 H20, forms white glittering crystals, somewhat soluble in Avater. Many quinine barks contain also quinidine and cinchonidine. Quinidine, C20H24N2O2, crystallizes with 2H20, and polar- izes to the right. It is also a nitrile base. Cinchonidine, Cj 9H22N20, forms anhydrous crystals. It solutions polarize to the left. It is also used as an antifebrile. Two alkaloids occur in the cusco chinchona-barks, viz., Cus- conine and Aricine, both having the formula, C23H26N204. The sulphate of the former is a characteristic salt, forming a gelatinous precipitate almost insoluble in water. The acid oxalate of aricine is also characteristic. It crystallizes in white prisms which after a short time change into rhombohe- drons very difficultly soluble in water. Both alkaloids polar- ize to the left. In the cinchona barks an acid, quinic acid, C7H]2On, occurs, which is combined partly with the alkaloids and partly with calcium. It is mono- basic, and hence contains only one carboxyl group, and belongs to the STRYCHNINE. 325 aromatic series. It is derived from a completely reduced benzene mole- cule (CCH12), U6H7(OH)4COOH. It forms colorless rhombic prisms easily soluble in water, and polarizing to the left. On oxidation it yields quinone, and on reduction benzoic acid. On fusion with potassium hy- droxide, it affords protocatechuic acid, C7HB04. The cinchona barks (and the tormentillo root) contain besides chinovic acid, C24H3b04, a glucoside, chinovin, C30H4BO&, which is decomposed by acids into a sugar, CcHi206, and chinovic acid. In them is also found a peculiar tannic acid called, quinotannic acid, which gives a green pre- cipitate with ferric salts, and is converted by the oxygen of the air into a red coloring matter, cinchona-red. Strychnine and brucine are found in the seeds of the Strychnos nux vomica, the beans of the St. Ignatius-bean, {Strychnos ignatii) and in snake-wood (roots of the Strychnos colubria). Strychnine, C21H22N202, is obtained by extracting theBar- badoes-nuts, or Ignatius-beans with boiling alcohol, and after throwing down the impurities with lead oxide, precipitating the strychnine and brucine with magnesia, and separating the strychnine by cold alcohol, in which the brucine is alone solu- ble. Strychnine crystallizes in colorless, rhombic columns which taste Aery bitter, are almost insoluble in water, absolute alcohol, and ether, but are easily soluble in ordinary alcohol. It is colored violet-blue by potassium chromate and sul- phuric acid. Nitric acid does not color it when free from brucine. It is a nitrile base, and unites with acids to form salts. It is extremely poisonous, causing tetanus even in small doses. It is used in medicine. Strychnine Nitrate, C21H22N202. HN03, forms colorless, silky needles with an extremely bitter taste, but little soluble in water and cold alcohol, more easily in hot alcohol. Brucine, C23H26N204, crystallizes with four molecules of water in four-sided prisms which effloresce when exposed to the air. It tastes very bitter, is difficultly soluble in water, 326 ALKALOIDS. insoluble in ether, but easily in alcohol. Nitric acid colors it red, giving a solution from which stannous chloride precipi- tates a violet substance. Its physiological action is less violent than that of strych- nine. It is converted into strychnine by oxidation with dilute nitric acid : C23H26N204 +40 = C21H22N202 + 2 C02 + 2 H20. Atropine, C17H23N03, is found in the berries of the deadly nightshade {Atropa belladonna) and in the thorn-apple {Datura stramonium). It crystallizes in thin needles which are easily soluble in alcohol, very difficultly in water and ether. It fuses at 115°, and is decomposed at a high temper- ature. It tastes intensely bitter, is very poisonous, and passes unchanged into the urine. It possesses the peculiar property of dilating the pupil very strongly, and is hence used in treat- ment of the eye. Its salts do not crystallize. On boiling with strong bases or acids, it is decomposed into tropine, C8H15NO, and tropic acid, C9H10O3 : C17H23N03 + H20 = C8H15NO + C9H10O3. On the other hand, tropine and tropic acid, when heated for a considerable time with very dilute chlorhydric acid at 100°, are converted into atropine. Atropine sulphate, (C,7H33N03)2. H2S04, is a white, bitter powder, very easily soluble in water and alcohol. Hyoscyamine, C]7H23N03, is the active principle of hen- bane {Hyoscyamus niger). It crystallizes in soft, silky needles soluble in alcohol, water, and ether. It fuses at 90°, and dilates the pupils. It possesses a sharp, offensive taste. When pure, it is odorless, but when impure has a strong offensive and stupefying odor. On boiling with acids or strong bases, it breaks into tropine, CeIIiSNO, VERATRINE. 327 and tropic acid, CaH,„03, yielding the same decomposition-products as atropine. Aconitine, C30H47NO7, exists in the purple monk's-hood {Aconitwn napellus) and forms a colorless powder without odor and with a bitter taste, causing a roughness in the throat. It is difficultly soluble in water, easily in alcohol. Veratrine, C32H49N09(?), is found in the seeds of the saba- dilla {Veratrum sabadilla) and, within; me, in the roots of the white hellebore ( Veratrum album). It is extracted with dilute chlorhydric acid. It crystallizes in rhombic prisms which effloresce in the air, fuse at 205°, are insoluble in water and easily soluble in alcohol and ether. It is very poisonous; the smallest amount brought in the nose, causes the most violent sneezing. Concentrated sulphuric acid colors it first yellow and then carmine-red. With concentrated nitric acid, it yields a dark violet solution on the surface of which drops of oil are formed. It forms crystalline salts. Jervine, C30H46N2O3 + 2 H20, is found, together with veratrine, in the roots of the white hellebore. It forms color- less prisms insoluble in water. With acids, it forms salts, most of which are very difficultly crystallizable. Berberine, C20H17NO4, exists in the roots of the Berberis vulgaris. It crystallizes with five molecules of water in fine yellow needles which lose their hydrate-water at 100°, fuse at 120° and decompose at a higher temperature. It is insoluble in water. Nascent hydrogen converts it into hydroberberine, C20H21N04. Piperine,'Gx 7Hj 9N03, is extracted from pepper by boiling with alcohol. Alkalis decompose it into piperinic acid, C12H10O4, andpiperidine, Cgl^N. C]7H19N03 + H20 = C12H10O4 + C5HnK Piperine forms colorless columns fusing at 100°, insoluble in water, easily soluble in alcohol and ether. Piperinic acid, 328 ALKALOIDS. ^12Hi 0C4J a bright-yellow, crystalline substance insoluble in water, yielding protocatechuic acid, C7H604, on fusion with potassium hydroxide. Piperidine, C5HMN, is a colorless, strongly alkaline liquid boiling at 106°, and forming well crystallizing salts. The nitrogen of piperidine binds a sub- stitutable atom of hydrogen, showing it to be an imido-base. Methylpiperidine, C6H10N"CH3, ethylpiperidine, benzoylpi- peridine, etc., have also been obtained. On heating with bromine, dibromoxypyridine, C5H3NBr20, is formed. The constitution of piperine is C6Hi0-N-CO-C4H4-C6H3/jT>CH2, and of piperidine chh' It is hence hexahydropyridin. Besides the alkaloids which have been mentioned above, there is a great number of others, of which we shall only men- tion the following. Eserine, or physostigmine, C15H21N302, occurs in the Calabar-bean, and is an intensely poisonous substance. It causes a contraction of the pupils. It is easily soluble in alcohol and ether, its solution decomposing very easily when exposed to the air. Sinapine, G1 cH23N06, exists as sulphocyanate in the seeds of the white mustard. The free base, owing to its instability, has not been obtained. The sulphocyanate forms fine needles fusing at 130°. On boiling Avith an alkali, it is decomposed into neurine, C5H16N02, and sinapic acid, Gii~H-1205. Lycine, C8HnN02, is found in the leaves of Lycium barbarum. Curarine, C10H15N, exists in curare, the Indian arrow poison. Harmaline, 013H14N20 > intheseedso{Peganumharmaia, Harnnne, C13H12N20) Cocaine, C, 7H21N04, in the leaves of the cocoa. GLUCOSIDES. 329 Colchicine, C17H19N05, is obtained from the seeds of the Colchicum autumnale, and is an amorphous powder which acts as a powerful emetic. Corydaline, C18H19N04, is contained in the seeds of the Bulbocapnus cavus. Chelidonine, C19H17N04, is extracted from the roots of the Chelidonium majus. Emetine, C30H46N2O7, exists in the ipecacuanha root {Radix ipecacuanha). It is a white, easily decomposable powder, fusing at 70°. It is a strong emetic. Solanine, C43H71N016, is contained in the germs of the potato. It forms colorless needles with a bitter taste, diffi- cultly soluble in water, and fusing at 235°. By boiling with dilute acids, it splits into sugar and solanidine, C25H41NO, which forms fine, silky needles, fusing at over 200°. It yields difficultly soluble, finely crystallizable salts. Glucosides. It has already been stated (p. 163) that the glucosides are substances occurring in plants, and are compounds of a sugar (usually dextrose) with other bodies, and are decom- posed by the action of ferments, acids, and alkalis into their constituents. Since plants generally contain these ferments, this decomposition of the glucosides takes place when the plants are allowed to remain for a length of time in contact with water. We have already met with a number of gluco- sides, e.g. indican, which is a compound of indigo with dex- trose, ruberythic acid, a compound of dextrose with alizarine, franguline, etc. Amygdalin, C20H27NOlt, occurs in the bitter almonds, the leaves of the laurel, and the kernels of cherries, apricots, peaches, etc. It is obtained from bitter almonds (previously freed from fat), by boiling with alcohol. It forms small, glit- tering scales, which are odorless, and possess a weak, bitter 330 GLUCOSIDES. taste. It is converted by dilute acids, or by the ferment, Emul- sin, which is contained in the almond, into dextrose, cyan- hydric acid, and benzaldehyde : C20H27NO11+2H2O = 2C6H12O6+HCN+C7H6O. On boiling with alkalis, it evolves ammonia and is decomposed into amygdalic acid, C20H28O13, the CN-group being con- verted into COOH. Salicin, Gx 3Hj 807, occurs in the bark of the willow and of numerous poplars. It forms small, glittering, bitter prisms, fusing at 198°, and difficultly soluble in cold water, but easily in hot. Ferments, e.g. emulsin, decompose it into dextrose and salicylic alcohol (saligenin). By the action of dilute acids, it breaks into dextrose and saleritin, a resinous substance arising from the decomposition of saligenin : Ca3H1807 + H20 = C6H1206 +C7H802. Coniferin, C16H2208+2 H20, exists in the cambial sap of the coniferce, and separates on concentration to \ of its volume. It forms glittering, efflorescent needles, fusing at 185°, and difficultly soluble in cold water, more easily in hot water and alcohol. It is decomposed by ferments into sugar and coniferyl alcohol, Cj 0Hj 203, and by oxidation into sucro- vanillic acid, C14H809 + H20, just as coniferyl alcohol is oxidized into vanillin, C8H803, and vanillic acid, C8H804 (methylprotocatechuic aldehyde and methylprotocatechuic acid). JEsculin, C15H1609 -f- 2 H20, occurs in the horse-chestnut, and forms fine, slightly bitter prisms, difficultly soluble in cold water and alcohol. Its solutions possess a blue fluorescence. It is decomposed by dilute acids into sugar and aesculetin, C9H604. ^Esculetin, C9H604 + H20, forms colorless needles, very difficultly soluble in water and alcohol. On boil- ing Avith potassa-lye, it is decomposed into oxalic, formic, and protocatechuic acids. QUERCITRIN. 331 Daphnin, which occurs in the barks of Ararious species of daphnia, has the same composition as sesculin. With fer- ments and dilute acids, it yields daphnetin, an isomer of cesculetin. Phloridzin, C21H24O10-{-2H2O, exists in the bark of the roots of the apple, pear, cherry, and plum trees. It forms fine, white, silky, glittering, bitter prisms, which are easily soluble in hot water and alcohol. On decomposition, it yields besides sugar, phloretin, C15H1405, which crystallizes in small leaflets, and is decomposed by alkalis into phloroglucin, CcH603, andphloretic acid, C9H10O3. Quercitrin, C36H38O20, occurs in the bark of the Quercus tinctoria, and is a yellow powder difficultly soluble in water. With acids, it yields isodulcite and quercetin, C24H16011. The latter exists in tea and in the bark of the apple-tree and other plants. It is a yellow powder subliming in yellow needles. It is but little soluble in water, easily in alcohol. By fusing with potassium hydroxide, it is decomposed into phloroglucin and quercetinic acid, C18H1209, which crystal- lizes in small prisms, and is converted into several other acids by continued action of potassium hydroxide. Hesper idin, C22H26012, exists in unripe oranges. It forms fine needles fusing at 245°. Acids break it into sugar and hesperitin, Gt 6H1406, which fuses at 223°, and is decomposed by potassa-lye into phloroglucin and hesperetinic acid, Ci0H1004. Arbutin, C25H34014, exists in the leaves of the arbutus. It crystallizes in needles fusing at 170°. It is decomposed by emulsin into sugar, quinol, and methylquinol. Myronic acid, C4 jHj 9NS20j 0, exists as a potassium salt in the seeds of the black mustard. It forms small, silky, glitter- ing needles. It is decomposed by myrosin, a ferment exist- ing in the seeds of the mustard, into sugar, mustard-oil, and potassium hydrogen sulphate : 0, ,H,8KNS204 0 = O.H, 2O0 + C3H5"NCS + KHS04. 332 COLORING MATTERS. Convolvulin, C31H50O16, is found in jalap-root. It is an amorphous mass fusing at 150°. Ferments convert it into sugar and convolvulinol, C13H2403 + ^ H20. ■ Jalapin, C34H56016, is found with convolvulin in the same root. It breaks into sugar and jalapinol, C16H30O3 + £H20. Saponin, C32H54018, occurs in numerous plants, particu- larly the soap-root. It is a white powder, the dust of which causes the most violent sneezing. Its solution foams like a soap solution, even when greatly diluted. It breaks into sugar and Sapogenin, G14H2 2 0 2. Helleborin, C36H4206, exists in Helleborus viridis, and hellebore'in, C26H44015, in Helleborus niger. They both crystallize in needles, and act as narcotics. The former de- composes into sugar and Helleboresin, C30H38O4, the latter into sugar and helleboretin, C14H20O3. Glycyrrhizin, exists in the liquorice-root. It is a white powder, which is decomposed by acids into dextrose and gly- cyrrhetin, a resinous body. Digatalin, is the active principle of Digitalis purpurea. It forms small colorless crystals very slightly soluble in water, easily in hot alcohol and chloroform. Dilute acids decom- pose it into sugar and digitalretin, an amorphous substance. On warming with concentrated chlorhydric or phosphoric acid, it assumes a beautiful green color. Coloring Matters. Some of the more important coloring matters occurring in nature, the constitution of which is accurately known, as well as some of those which have been produced synthetically, have already been mentioned, e.g., indigo-blue and alizarine. Color- ing matters are of both vegetable and animal origin. In the former case, they do not usually exist already formed, but united with sugar as ethers, and are set free by fermentation, COLORING MATTERS. 333 and by the action of dilute acids and alkalis. The substances occurring in plants are, hence, glucosides, and are called, when the substance united with the sugar is a coloring matter, chromogenes. The coloring matters all belong to the aromatic series. They possess in general weak acid properties, are soluble in alkalis with a peculiar color which is not usually that of the free coloring matter, and form insoluble compounds with metallic oxides, particularly with the oxides of lead, tin, iron, and alumina, as well as with animal, and occasionally vege- table fibres. Dyeing depends on the animal or vegetable fabric, either by itself or impregnated with a solution of alumiuum acetate, lead oxide, etc., attracting the dissolved coloring matter and forming with it an insoluble compound. When the dye deposited on the fibres is insoluble in acids and alkalis it is called "fast," but when acted on, it is desig- nated "not fast," or "fugitive." Owing to the different degrees of solubility of the coloring matters, this classification is naturally very imperfect. Coloring matters are decomposed by oxidizing agents. The ozone and hydrogen peroxide of the air, or, better still, chlo- rine, decompose almost all coloring matters, or as it is ex- pressed, "bleach" them (chlorine-bleach, grass-bleach). Sulphurous acid bleaches many coloring matters, particu- larly those of animal origin, forming with them colorless compounds, which, however, are decomposed by strong acids (sulphuric acid) with regeneration of the color. A great number of coloring matters which occur in nature have been produced by artificial means, e.g., the aniline colors, eosine, naphthalene-yelloAv, etc. A series of homologous compounds, which are anhydride compounds of- acids, occur in the lichens. Most of them yield on decomposition orcinol, C7Hb02 (see p. 249), which with ammonia, forms lichen-red, or orcein. The Rocella tinctoria contains orsellic acid, CiGHi4Or, the salts 334 COLORING MATTERS. of which when boiled with water yield orsellinic acid, CeHe04. Orsellinic acid decomposes into orcinol C7H„02, and carbonic acid. As the constitution of orcinol is C6n3 j j^9' orsellinic acid is : ((OH), CeH2 •< CH3 , (COOH and orsellic acid is the anhydride of orsellinic acid : n/C6H2(C02H)(CH3)OH U\C0H2(CO2H)(CH3)OH- Evernic acid, Ci7Hi607, occurs in the Everniaprunastri. On boiling with alkalis, it breaks into everninic acid, CaHi0O4, and orsellinic acid, CsH804 : Ci7Hi607 + H20 = C9H10O4 + C«H804. OH Everninic acid has the constitution, C6H2 \ PTt 3. Evernic acid is CH COOH hence : n/C6H2(COOH)(CH3)(OCH3) u\C6H2(COOH)(CH3)(OH) " TJsnic acid, Hi9Ci607, exists in numerous lichens (cladonia, evernia, parmelia and usnea). Its last decomposition-product is betaorcinol, C«H10O2. Betaorcinol is probably, C7H5 -j ^L ^a. Usinic acid is hence : n/C7H4(C02HXCH3)(OH) u\C7H4(C02H)(CH3)(OH)- The Rocella fuciformis contains erythric acid, C20H22Oi0, which, on boiling with alkalis, splits into orsellinic acid, C„H804, and picroerythrin, Ci2Hi607. The latter on continued boiling with alkalis, is decomposed into carbonic acid, orcinol, CGH3 -j ppj , and erythrol, (p. 138), C4Hi0O4. Picroerythric acid is hence the erythrol compound of orsellinic acid : (C02H 1 PIT C6H2 -j qjj3 , and erythric acid is therefore : ( 0"C4H903 LOG-WOOD. 335 n /CeH2(C02H)(CH3)(0-C4H!, 03) u\C6H2(C02HXCH3)(OH) All of the lichen-acids (orsellic, evernic, usnic, and erythric), except evernic acid, are crystaUine compounds. They are colored red by calcium hypochlorite, or on exposure to the air in presence of ammonia. Orcinol is the final product of the action of alkalis on all of them. Vulpinic acid, Ci9H1405, exists in Cetraria vulpina. On boiling with barium hydroxide, it is resolved into alphatoluic acid, CoH5~CHa"C02H (p. 262), methyl alcohol and oxalic acid : C19H1405 + 4 H20 = 2 C8Hs02 + C2H204 + CH40. Alphatoluic Oxalic acid acid It forms with alkalis and alkaline earths, yellow or orange-colored salts which are soluble in water. Log-wood {Hoematoxylon campechianum) contains hematoxylin: C16Hi406 + 3 H20, which can be extracted with water. It forms yellow, transparent prisms with a sweet taste, and soluble in alkalis with a purplish-red color. Its solution in ammonia oxidizes rapidly in the air, being converted into the ammonium salt of a red coloring matter, haimate'in, CiGHi0O5. The solution becomes continually darker red. The haematein can be precipitated by acetic acid. Santalin, Ci5H1405, exists in sandal-wood. It forms microscopic red crystals, which dissolve in alkalis with a violet color. Brasilin, Ci6Hi405, exists in Brazil-wood. When pure it forms al- most colorless prisms, which become first yellow and finally carmine-red when exposed to the air. It dissolves in dilute sodium hydroxide lye with a beautiful carmine-red color. The alkaline solution is bleached by acids. It is oxidized by nitric acid to trinitroresorcinol, and on dry dis- tillation it yields resorcinol abundantly. In alkaline solution, it is oxidized when exposed to the air into brasilevi, Ci6Hi20r„ which forms silvery, glittering leaflets dissolving in alkalis with a purplish-red color. Safflor (flowers of the Carthamus tinctorius) contains both a yellow and a red coloring matter. The latter, carthamin, Ci4H,607, is a dark-red powder with a green reflex, soluble in alkalis with a yellowish-red color, and in this solution not stable. When fused with potassium hydroxide, it yields protocatechuic acid, CGH3(C02H)(OH)2. Polychro'it, C48HG0Oi8, exists in saffron (Crocus sativus). It is an 336 COLORING MATTERS. orange-red substance which is resolved by acids into sugar, an oxygenated oil, Ci0Hi4O, and a red body, crocin, Ci6Hib06 : C46H6oOie + H20 = 2 CiGH1806 + CioHi40 + C6Hi20G. In tumeric, a yellow coloring matter called curcumin, Ci4Hi404, occurs. On oxidation with potassium dichromate and sulphuric acid, it yields acetic and carbonic acids, while by incomplete oxidation with potassium permanganate, vanillin (methyl ester of protocatechuic aldehyde) is pro- duced. Di-ethylcurcumin affords ethylvanillin. Curcumin is hence : (1 CH(C5H6)C00H C6H3 \ 3 OCHs (4 OH It forms stout needles fusing at 178°, and soluble in alkalis and alkaline carbonates with a brownish-red color. Paper colored yellow with curcu- min is turned brownish-red by alkaline liquids, and on drying becomes violet. Acids turn it yellow again. When tumeric paper is moistened with a solution of boracic acid and dried, it turns orange-red. This color is not affected by acids, but is turned blue by alkalis. In the cochineal, the female of an insect (Coccus cacti) and in the flowers of the Monarda didyma, a red coloring matter, carminic acid, Ci7H16Oi0, occurs. On boiling with dilute acids, it breaks into carmine- red, CiiH]207, and a species of sugar, C6Hio06. On heating with con- centrated sulphuric acid at 150°, it evolves carbonic acid, and is oxidized into ruficoccin, CiGH1206 : Ci,H,sO10 + 0 = C16H1206 + C02 + 3 H20. Boiled with nitric acid, it is converted into nitrococcussic acid: C8H5(N02)303. Nitrococcussic acid is a tri-nitro-cresotic acid, C8H803, and its constitu- tion is hence : C6(N02)3(CH3)(OH)(C02H). The constitution of ruficoccin is probably : ((CH3)2 C,4Hi2-UOH)4 , (o2 i.e., the tetra-hydroxylated quinone of dimethylanthracene. BITTER PRINCIPLES. 337 The most widely distributed coloring matter is the green matter of leaves, and is called chlorophyll. But little is as yet known about it. lb appears to be a mixture of a yellow and a blue coloring matter. In au- tumn, the blue substance disappears, and, as the leaves contain then only the yellow coloring matter, they appear yellow. Bitter Principles. The so-called bitter principles are closely related to the col- oring matters and lichen-substances. They have an intensely bitter taste. A number of glucosides are sometimes placed in this class. The bitter substances are the active principles of many important medicinal plants. Aldin, C15H1607, is the active constituent of aloes. It forms small colorless crystals with a sweetish, bitter taste, and varying percentage of water. It easily becomes amorphous. On warming with nitric acid, it yields chrysammic acid (tetra- nitro-chrysazin, p. 304), C14H2(N~03)402(OH)2, which crys- tallizes in golden-yellow, difficultly soluble leaflets, decompos- ing by fusion with potassium hydroxide into oxalic acid, orcinol, panoxybenzoic acid, and alorcinic acid, C9H10O3 -f H20 (fine needles fusing at 115°). Santonin, C15H1803, exists in worm-seed, and forms col- orless, pearly, glittering leaflets very difficultly soluble in water, quite easily soluble in alcohol, and fusing at 170°. It is the anhydride of santonic acid, C, 5H20O4, into which it is very easily converted by bases. Sodium santonate, C15H19Na04+3H20, forms colorless rhombic crystals. Acids decompose it, setting free santonic acid. The acid passes very easily into santonin. Both santonin and sodium santonate, turn yellow on standing exposed to the light. Picrotoxin, C21H1405, is contained in the seed of the 22 338 BITTER PRINCIPLES. Menispermus cocculus. It crystallizes in glittering needles, somewhat soluble in water. It reduces alkaline cupric solu- tions and is poisonous. Cetrarin, Gt 8B.t 608, which occurs in Iceland moss, crystal- lizes in needles insoluble in water, easily soluble in alcohol. It dissolves in alkalis and alkaline carbonates with a yellow color. Quassiin, C10H12O3, is the bitter principle of quassia- wood. It forms colorless leaflets with an extremely bitter taste. It is but little soluble in water, easily soluble in alcohol. Absynthin (C20H28O4 ?), is produced from worm-wood, Artemisia absynthium. It is a very bitter substance with the odor of worm-wood. A large number of the substances of this class have been al- ready mentioned under glucosides. The following acrid principles are intimately related to the bitter principles. Cantharidin, C10H13O4, is the active principle of the Spanish-fly. It crystallizes in colorless columns, and when pure is insoluble in water. It produces blisters on the skin. Cossin, C26H3205, is the active principle of the cosso. It is yellow powder with a peculiar odor and a bitter, harsh taste. It is difficultly soluble in water, easily in alcohol, ether, and alkalis. Betulin, C36H60O3, exists in the bark of the birch. It crystallizes in large, thin prisma fusing at 251°, insoluble in water and difficultly in alcohol und ether. Carotin, C18H240, is found in minute crystals in the cells of the yellow carrot. The carrot owes its color to the pres- ence of this substance. It crystallizes in reddish-brown cubes, fusing at 168°, is insoluble in water, difficultly in alcohol, and possesses a fragrant odor. Chrysin, Gt 6H, 0O4, is contained in the buds of the poplar. BILIARY SUBSTANCES. 339 It forms bright-yellow tablets fusing at 275°, insoluble in water, difficultly soluble in alcohol and ether, and more easily in alkalis, forming with the latter an intense yellow solution. Ostruthin, C28H3404, is found in the roots of the Impera- toria ostruthium. It crystallizes in colorless needles fusing at 115°. Its alcoholic solution exhibits a blue fluorescence. Alkalis dissolve it with a yellow color. Peucedanin, C10H16O4, occurs in the roots of the Peucedanum officinale, and forms colorless prisms fusing at 76°. Alcoholic potassa, or concentrated chlorhydric acid, de- composes it into oreoselon, C14H1204, which crystallizes in needles fusing at 177°. Cascarillin, C12H1804, is found in cascarilla-bark. It crystallizes in colorless, bitter prisms fusing at 205°, diffi- cultly soluble in water and easily in hot alcohol. Columbin, C21H2 20„ occurs in the columbo-root, and forms colorless, bitter prisms. Smilacin, G18H3 0O6, exists in sarsaparilla. It crystallizes in colorless prisms, which are slightly soluble in hot water, form- ing a strongly foaming solution with an offensive taste. Biliary Substances. Before passing to the description of the more important parts of the animal organism, we shall take up the properties and metamorphoses of several compounds which occur in them. The chief constituents of the bile are the potassium and sodium salts of two acids, viz., glycocholic and taurocholic acids. Glycocholic acid, G2 6H4 3N06, forms fine needles, almost in- soluble in water, easily soluble in alcohol, and possessing a sweet taste and an acid reaction. It is a monobasic acid. When mixed with a solution of sugar, and then treated with concen- 340 BILIARY SUBSTANCES. trated sulphuric acid, it yields a deep purplish-red solution. On boiling with dilute acids, it is resolved into glycocoll, C2H5N02 (p. 98), and dyslysin, C24H3603 : C26H43N06 - O.H.NO, + C34H3603 + H20. Dyslysin is an amorphous body, insoluble in water. When glycocholic acid is boiled with alkalis, it splits into glycocoll and cholic acid, C24H40O5 : C26H43N06 + H20 = C2H6N02 + C24H4908. Cholic acid crystallizes with 2£H20, in colorless, glassy octahedrons which are insoluble in water. Taurocholic acid, C26H45NS07, forms colorless needles easily soluble in water and alcohol. Its solution turns the plane of polarized light to the right. On boiling with water, or more quickly with dilute acids or alkalis, it is decomposed into cholic acid, C24H40O5, and taurin, C2H,NS03 (p. 82): C26H45NSO, + H20 = C24H40O5 + C2H7N03S. Both glycocholic and taurocholic acids exist in varying pro- portions in the bile of almost all animals. To this the bile of the pig is an exception, as it contains two other acids, the hyoglycocholic and hyotaurocholic acids. Hyoglycocholic Acid, C27H43N05, is a colorless amorphous mass, which is insoluble in water and easily soluble in alcohol. Its salts taste bitter. Its alkali salts are soluble in water, its others insoluble. It is resolved by boiling with dilute acids or alkalis, into glycocoll, C2H5N02, and hyocholic acid, C25H4004 : C27H43N05 + H20 = C2H5N02 + C26H40O4. Hyocholic acid forms warty crystals insoluble in water. Hyotaurocholic Acid, C27H45NOs, exists in only very small amounts in the bile of the pig. It breaks on treatment with alkalis, into taurin, C2H7NS03, and hyocholic acid, C2SH40O4. PROTEIN SUBSTANCES. 341 The bile contains, besides the two acids mentioned, another constituent, viz., cholesterin. Cholesterin, C26H440, exists also in the blood, brain, and yolks of eggs. It occasionally occurs in such amounts in the bile that it separates, forming what are known as "gall-stones." It is the chief constituent of the fat of wool. It has been proved to exist also in plants. It crystallizes in colorless, glittering leaflets or silky needles, with one molecule H20, fusing at 145°, boiling at 360°. In- soluble in water, and soluble in alcohol. It is an alcohol, and forms a chloride, C26H43C1, ether, etc. The bile contains certain coloring matters to which it owes its peculiar color, golden-yellow in man and grass-green in herbivora. Bilirubin, Ci6H,hN203, is a bright-red powder which changes to brown on exposure to the air. It is insoluble in water and alcohol, but in alkalis it is very easily soluble, with an orange-red color, which on very great dilution is yellow. In the disease known as icterus, it causes the yellow color of the skin. It absorbs oxygen and becomes green, which accounts for the golden-yellow color of bile turning to green when exposed to the air. The bilirubin is hereby changed into biliverdin, C,6Hi8N204, a blackish-green powder, insoluble in water and soluble in alcohol. It is colored yellow by sulphurous acid. Both bilirubin and biliverdin, when treated in al- kaline solution with ordinary nitric acid, which always contains nitrous acid, give characteristic color-reactions. The solution becomes green, and passes through blue, violet, ruby-red into a dirty-yellow. Gall-stones, contain a small amount of bilifuscin, CiBHo0N204, a brit- tle, glittering almost black mass. The following coloring matters are also found in bile, but in small amounts. Biliprasin, Cl6H22N206, a glittering, almost black mass. Bilihumin, a blackish-brown powder which is formed from the other biliary coloring matters on exposure of their alkaline solutions to the air. Protein Substances. A number of very highly constituted substances, some solid and some in solution, occur in animal and vegetable organ- isms. They are very intimately related to each other, and 342 PROTEIN SUBSTANCES. are called protein, proteids, albuminous substances, and albu- minoids. They all contain carbon, hydrogen, oxygen, nitro- gen, and sulphur. The various kinds show small differences in composition from each other, but our methods of analysis are not delicate enough to enable us to assign them even an empirical formula. In plants, the protein bodies are contained in far less amounts than the carbhydrates, but in the animal kingdom they form the chief part of the organic constituents. They are formed, however, only in the plant, and are introduced into the animal organism through plant-food, being only assimilated and further changed by the animal. They exist either in solution (vegetable and animal liquids) or undis- solved, in a soft, moist state, as organized structures, or amorphous, as the coagulum in liquids. Their being in solution in plants and animal structures is owing to the presence of small amounts of bases, acids, or salts. They can be precipitated from these solutions by boiling, or by alkalis, acids, and various salts. Precipitated in this manner, they form usually an amorphous, flocculent, soft, odorless and tasteless mass, which when dried is transparent and brittle. It is insoluble in pure water, but soluble in dilute alkalis. They are very unstable, being slightly decomposed even by precipitating from a solution and redissolv- ing. When kept in a moist state, they decompose quickly, becoming putrid, and yielding a great number of less highly constituted bodies (carbonic acid, volatile fatty acids, fats, lactic acid, ammonia, amine bases, ammonium sulphide, leucine, tyrosine, etc.). Putrefying albu- minous substances impart their chemical activity to many other sub- stances, thus acting as ferments, or starting fermentation. They are resolved by reduction with stannous chloride and chlorhydric acid into leucine, CGHi3N02, tyrosine, C9Hi;N03, asparaginic acid, C4H7N04, and an acid homologous with asparaginic acid, glutamic acid, C5H9N04. Tyrosine, Hydroxyphenylamidopropionic Acid : C9HuN03 = C0H4(OH)-C2H3(NH2)COOH, is a decomposition-product of albuminous substances, and is hence found in putrefying animal liquids, rotten cheese, etc. It is a white, crystalline powder, very difficultly soluble in cold water, but more easily in hot. It is an amic acid, and unites with both acids and bases. It is hence easily soluble in alkalis and dilute acids. It yields a nitro-product with nitric acid, and with sulphuric acid, a sulphonic acid. ALBUMINS. 343 Albumin is recognized by the following reactions : On warming with concentrated nitric acid, it becomes yellow (xantho- protei'n reaction). On boiling with a solution of mercuric nitrate and then adding a trace of nitrous acid, it becomes red (Millon's reaction). Treated with concentrated sulphuric acid and then with a solution of sugar, it becomes red and then violet-red. On boiling for some time with concentrated chlorhydric acid, in which it dissolves on heating, it affords an intense violet-red solution. All of the albumins go into solution when digested with the acid juice of the stomach at 30-40°, producing the so- called peptones, which are really a mixture of leucine, tyrosine, etc., and no longer albuminous substances. There are four classes of albuminous bodies, the differences between which, however, are very slight. 1) Albumin, Egg-albumin, Serum-albumin, Vegetable-albu- min, and Globulin. They are precipitated (coagulated) by warming their solutions to 60-70°. 2) Casein, Animal-casein, and Plant-casein {Legumin). They are coagulated by the mucous membrane of the stomach of the calf (rennet). 3) Fibrin, Blood-fibrin, Muscle-fibrin {Myosin), and Glu- ten. They become insoluble as soon as they have left the organism. 4) Proteids, Hemoglobin, and Vitellin. They are resolved by various agents into albumin and other substances. Albumins. The albumins occur in the juices of plants, and can be extracted from the dried plants with cold water. They also occur in the whites of birds' eggs, in the milk of animals, in the plasma of the blood, chyle, lymph, in the serous liquids, juices of the muscles, animal semen, and in the nu- tritive liquids. In all cases, it is held in solution by the salts 344 ALBUMINS. contained in the liquids, and can always be precipitated by dilution with a large amount of water. Solutions of albumin become turbid at 60°, and at 75° the whole of the albumin separates in white flocks (coagulation). If only a small amount of salts or acids is present, a lower tempera- ture is sufficient to precipitate the albumin. But if small amount of alkalis is present, a higher temperature is required for coagulation. Strongly alkaline or acid solutions of albumin are not precipitated by heating. Hydrogen sulphide is set free during the coagulation of albumin. Coalgulated albumin is insoluble in water. A solution of albumin which has been strongly acidified ie.g. with chlorhydric acid of 0.2$), loses its property of coagulating, but coagulates on neutralization with a base. The solution contains the so-called acid-albumin. When coagulated albumin is treated with concentrated po- tassa, a solid elastic jelly is obtained, which on washing loses alkali until a constant composition has been attained. This albumin is called alkali-albumin, and is insoluble in cold water, soluble in hot, its solution remaining clear after cool- ing. The animal and plant organisms contain many albumins in the form of alkali-albumins. A peculiar modification of albumin exists in the crystalline lens of the eye, and is called Crystallin. It also occurs in small amounts in the white of egg, chyle, etc., and is termed Globulin. It is precipitated from its solution by carbonic acid as a white powder. Among the substances resembling albumin, are Paralbumin, which exists in dropsical ovaries, is only partly precipitated by boiling, and is soluble in water ; Pancreatin, which is contained in the juice of the pancreas ; Ptyalin, which exists in the saliva ; Diastase, which is found in germinating barley. The last three convert starch into sugar. FIBRIN. 345 Casein. The caseins are alkali-albumins which are precipi- tated by alcohol, metallic salts, and acids. The pure solutions do not coagulate on boiling, except after addition of calcium chloride, calcium sulphate, magnesium sulphate, etc. The natural solutions (milk) coagulate (curdle) slowly on exposure to the air, because lactic acid is formed from the milk-sugar. They are also coagulated by calf-rennet, probably owing to the presence of a ferment in it. The animal casein exists chiefly in milk. The vegetable casein (legumin) occurs principally in the almonds and leguminosse. Fibrin is found in the blood, chyle, lymph, and in many serous exudations. TI13 blood coagulates (clots) after removal from the animal organism, the coagulum, or clot, being the fibrin. By beating the blood with a glass rod, it can be obtained in a fibrous state. It forms a white, tough, amor- phous mass. Fibrin does not exist as such in blood, but is formed by the union of paraglobulin and fibrinogen. The paraglobulin is contained in the red- blood corpuscles and diffuses out of them into the liquid of the blood (plasma), being found, after the coagulation of the blood, in the remain- ing serum, as it is present in large amounts. It is precipitated from its solutions by carbonic acid, and resembles globulin very much. The muscles contain a liquid (muscle-protoplasm) which after death coagulates and becomes solid {rigor mortis). The insoluble body thus separated, is called myosin, or flesh-fibrin. The vegetable substance analogous to fibrin is known as gluten. It can be obtained by kneading wheat-flour on a sieve with water. The starch is washed through, and the gluten remains. It is a mixture of various substances, gluten- fibrin, gluten-casein, mucedin, and gliadin. Protei'ds. The red color of the blood is due to the presence of a red coloring-matter. This substance can be obtained in 340 PROTEIDS. microscopic, but beautifully formed crystals, and is called Haemoglobin. It crystallizes with hydrate-water, which it gradually loses on exposure to the air, and dissolves in water to a red liquid. On boiling this solution with alcohol, a rusty colored precipitate separates, which, after washing out with acidified alcohol, becomes colorless, and is albumin. The coloring matter, which is soluble in acidified alcohol, is called haematin. Haematin contains iron. On heating it is decomposed, and on igniting in the air it leaves a residue of pure ferric oxide. Its composition is C34H34N405Fe. The haemoglobin effects the absorption of gases by the blood. It absorbs oxygen with avidity, and gives it up again as soon as another gas {e.g. carbonic acid) is passed through it to saturation. It takes up ozone from substances containing it, and gives it up again as oxygen. On taking up oxygen, its color becomes brighter red, while with carbonic acid it becomes dark red. Hence blood containing oxygen (arterial blood) is bright-red, while blood containing carbonic acid (venous blood), is dark. It unites with carbonous oxide, forming a crystalline bluish- red compound, which is more stable than oxygenated haemo- globin. With nitrogen di-oxide and cyanhydric acid it forms compounds which are more stable than with carbonous oxide. The three compounds just mentioned, CO, NO, and HON, are hence powerful poisons, and produce death because they render the haemoglobin incapable of taking up oxygen. Hoematin, which is the decomposition-product of haemo- globin, is a bluish-black powder, insoluble in water, alcohol, and ether, and soluble in alkalis, ammonia, and dilute acids. It forms with chlorhydric acid, a crystalline compound, which is used as a characteristic test for the presence of blood. If a fragment of dried blood is placed on the object-glass of a micro- scope, a grain of salt added, then covered with a glass plate, the powder NEURIN. 347 moistened with a drop of glacial acetic acid and warmed till the acetic acid begins to evolve bubbles, and then allowed to cool, the field will be found to be filled with minute black crystals of haematin. The spectrum of a haemoglobin solution shows two absorption- bands, which have, however, different positions, depending on whether the haemoglobin is saturated with oxygen, nitric oxide, or carbonous oxide. In the yolks of eggs, there is a substance which, besides the elements common to albumins (C, H, N, 0, and S), contains phosphorus, viz., Vitellin. It is decomposed by warm alco- hol with the separation of albumin, while another substance, Lecithin, which contains all the phosphorus of the vitellin re-> mains in solution. Lecithin, C42H84lSrP09, is a peculiar glyceride. It forms a crystalline mass easily soluble in alcohol, which, on boiling with dilute acids, or alkalis, is resolved into oleic acid, C18H3402, palmitic acid, C16H3202, neurin, C5H15N"02, and glycerylphosphoric acid, C3H102. H2P04 (see p. 119). Neurin, which can be produced artificially by heating tri- methylamine, (CH3)3N, with glycolchlorhydrin, CH2(0H)-CH2C1, has the constitution: CH2(OH)"CH2N(CH3)3OH. It is an ammonium base, the nitrogen of which is united with three methyl-groups, one hydroxyl-group and the di-valent rest of glycol (glycol minus OH). It crystallizes in deliques- cent needles which possess strong basic properties, attract car- bonic acid from the air, and on boiling, break into tri-methyl- amine arid glycol. It forms finely crystallizable salts with acids. On oxidation, it is converted into oxyneurin, CsHt 3N03, which occurs in the red-beet {Beta vulgaris). It is made 318 ALBUMINOIDS. artificially by the action of tri methylamine on monochloracetic acid, CH2C1~C02H. Its constitution is hence, COOH-CH2_N(CH3)3OH. It forms large deliquescent crystals with basic properties. From the above-mentioned facts, it is possible to derive the constitution of lecithin. It is glycerol in which 2 H's are replaced by the rest of oleic and palmitic acids, and a third H by the rest of phosphoric acid, while an H of the phosphoric acid rest is replaced by the rest of neurin : CH2-0-C,,JI330 CH-0-C1GH310 CH2_0"PO\0-CH2-OH2-N(CH3)3OH. As has already been stated, the composition of the various proteids can only be expressed in percentages, and not by chemical formulas. The fol- lowing will serve as examples : Egg-albumin Blood-albumin VegeUble-albnmin Blood-fibrin Vegetable-fibrin C = 53.4 $ 53.0 $ 53.4$ 52.6$ 53.4 H= 7.0$ 7.1$ 7.1$ 7.0$ 7.1 N = 15.6$ r>.6$ 15.6$ 17.4$ 15.6 0 = 22.4 $ 23.1$ 23.0$ 21.8$ 22.8 S = 1.6$ 1.2$ 0.9$ 1.2$ 1.1 Milk-casein Legumin-case'in Almond-casein Haemoglobin C = 53.6$ 51.5$ 50.8$ 53.8$ H = 7.1 $ 7.0$ 6.7$ 7.3$ N = 15.7 $ 16.8$ 18.4$ 16.1$ 0 = 22.6 $ 24.3$ 23.7$ 21.9$ S = 1.0$ 0.4$ 0.4$ Fe 0.5$ = 0.4$. We come now to a series of nitrogenous bodies which are intimately related to the protein substances proper, and which are derived from them, but which differ from them in con- taining much less carbon. Tliey possess the general name of Albuminoids. In many pathological conditions, the cells and tissues suffer a peculiar change and assume a waxy consistency. A sub- GLUE. 349 stance is hereby formed which is colored reddish-brown by iodine, and green or blue when first moistened with concen- trated sulphuric acid. As these reactions resemble those of starch (amylum), this substance is called amyloid. It is a colorless, crumbly mass, insoluble in water, alcohol, and ether. It passes with difficulty into putrefaction. Animal connective tissues, on continued boiling with water, form a clear solution, which, when cool, solidifies to a soft elastic mass. This gelatinizing substance is called glue. There are two species of glue, viz.: glutin and chondrin. Glut in is obtained by boiling bones, tendons, skins, etc., with water. It forms, when dry, a colorless, transparent, brittle mass, which swells up in water, and at 40° absorbs water without dissolving. It forms a thin solution when boiled with water, which gelatinizes on cooling. It loses the property of gelatinizing, if boiled repeatedly with water, more quickly when boiled with dilute acids, or by heating to 140° with water in closed vessels. It is precipitated from its solution by alcohol and tannic acid. Concentrated sulphuric acid decomposes it, forming, besides other products of decomposition, chiefly glycocoll and leucine. In the moist state, it passes easily into putrefaction. Chondrin is prepared by boiling young bones, which are still soft, and cartilage with water. It resembles glutin very much, and is only distinguishable by its being precipitated from its aqueous solution by dilute acids and the salts of iron, copper, lead, and silver. It is not precipitated by mercuric chloride. By the action of sulphuric acid, leucine only and no glycocoll is produced. It is also decomposed by concentrated chlorhydric acid, a fermentable sugar, chondroglucose, being produced among other substances. The horny tissues, e.g., hair, wool, feathers, nails, claws, talons, hoofs, horns, epidermis, epithelium, etc., contain as a chief constituent, keratrin. Keratrin does not form a glue 350 ALBUMINOIDS. with water, but dissolves when digested with it at 150°, yield- ing a clear solution which does not gelatinize on cooling. Hair and wool contain considerable sulphur (about 5$), a part of which is so loosely combined, that it will unite with lead or silver. This explains the blackening of the hair when combed with a lead or silver comb. Mucin exists in the saliva, mucus, bile, synovia, urine, semen, excrement, and glands. It is a colorless, opaque, flocculent mass, which, on drying, becomes brittle and horny. It is insoluble in water, but swells up in it. It is soluble in a dilute salt solution. Its solution is glairy and ropy, and foams on shaking. It does not contain sulphur. Elastin is the basis of the elastic tissues. In a moist state, it is very elastic, insoluble in water, dilute acids and alkalis. When dry, it is hard and brittle, but swells up when placed in water. On boiling with sulphuric acid, it yields leucine, but no tyrosine. Silk-fibrin is an albuminoid, and the chief constituent of silk. It is a white, glittering mass, insoluble in water, and soluble in alkalis and concentrated acids. On boiling with dilute sulphuric acid, it yields.leucine, tyrosine, glycocoll, and sugar. The important difference between vegetable and animal life consists in the former producing highly constituted com- pounds from simpler substances; as carbonic acid, ammonia, water, etc., which are taken up from the earth and atmos- phere. Animals, on the other hand, consume the compounds built up by plants, and decompose them into the original simple compounds. Plant life is a synthetic and reduction process (plants principally inhale carbonic acid and exhale oxygen), while animal life is an analytical and oxidation proc- ess (animals inhale oxygen and exhale carbonic acid). Appendix. There are two methods by which the constitution of a compound can be determined. Both of them are usually employed. Complicated substances are decomposed by simple reactions into simpler bodies, the constitution of which is known, or more complicated compounds are produced from simple substances of known structure. The former method is the analytic, the latter the synthetic. Both of the meth- ods will be described, but it is first necessary to explain the methods for the determination of the percentage composi- tion and molecular weight of compounds. Determination of the Composition of Organic Substances. Estimation of Carbon and Hydrogen.—Carbon and hydrogen are always estimated in a single operation. As it has already been stated in the introduction, the carbon is oxidized to car- bonic acid and the hydrogen to water. Two substances rich in oxygen are used as oxidizing agents, viz., cupric oxide, CuO, and plumbic chromate, PbCr04, or a mixture of both. The combustion is effected in a tube of difficultly fusible glass GO-70 cm. long (Fig. 1). The glass tube is drawn out at one end into a narrow tube turned up at an obtuse angle and the end closed by fusing. The tube is half filled with freshly ignited, perfectly dry cupric oxide, or plumbic chromate (to b), and a weighed amount of the substance mixed in by means of a brass rod which is bent at the end in the form of a cork- screw. The remainder of the tube is then filled with cupric 351 352 APPENDIX. oxide and closed with a tightly fitting cork through which passes a U-tube filled with calcium chloride {d) ; the calcium. chloride absorbs the water formed by the combustion. Con- nected with this tube, is a peculiar bulb-apparatus (e) (Lie- big-bulb), which serves to absorb the carbonic acid. It is filled with a concentrated solution of potassium hydroxide, and connected with a small U-tube (/) which is filled with small pieces of potassium hydroxide, which absorb the last traces of carbonic acid, and also take up any moisture which may be carried from the potassa solution by the stream of gas. Fig. 1. By gently tapping the tube, a canal is formed for the evo- lution of the gaseous products of combustion. The tube is then placed in the combustion furnace and heated. Figure 1 represents the combustion tube filled and ready for analysis. Fig. 2 shows the whole apparatus. Up to a is pure cupric oxide ; a-b is the mixture of the substance and cupric oxide ; b-c is again pure cupric oxide ; d is the calcium chloride tube ; e is the bulb-apparatus filled with potassium hydroxide solution ; / is the tube filled with solid potassium hydroxide. Both the calcium chloride tube and the potash-bulbs are weighed before the combustion. The tube is gradually heated to a red heat, beginning at c and advancing slowly, till the whole tube is heated. The operation is observed by the passage of the bubbles through e. When the combustion is ended, the potassa solution rises in the bulb nearest the calcium chloride 3 354 APPENDIX. tube. The flames are then extinguished, the point of the tube broken, and air, which has been freed from carbonic acid and moisture by passing through a solution of potassium hydroxide and over calcium chloride, is drawn through the tube in order to remove the last traces of moisture and carbonic acid remaining in it. The calcium chloride tube and the potash-bulbs are then again weighed, and the differences be- tween the first and last weights give the amounts of moisture and carbonic acid which have been formed by the combustion of the hydrogen and carbon in the substance. The weight of water obtained is to the weight of hydrogen in the substance as H20 : H2, or as 18 : 2, or as 9 : 1, i.e., the weight of the hydrogen is \ of the weight of water found. The relation between the carbonic acid and the carbon is as C02 : C, or as 44 : 12, or as 11 : 3. The weight of the car- bon is hence T3T of the weight of the carbonic acid found. If the substance to be analyzed is a liquid, it is introduced into a small glass bulb, Fig. 3, by placing the point under the surface of the liquid and warming the bulb. On cool- „. ing, the liquid rises and fills the bulb. The point is then fused. The combustion tube is filled to a with cupric oxide, the bulb thrown in with such force that it is broken, the remainder of the tube then filled with cupric oxide, and the operation carried out as in the preceding case. If the substance contains, besides carbon and hydro- gen, nitrogen, a part of the oxygen of the cupric oxide unites with the nitrogen, forming NO, which is absorbed with the carbonic acid, by the potassa, thus rendering the determination of the carbonic acid valueless. In this case, a layer of metallic copper is placed in the A front part of the tube. Copper possesses the property of decomposing NO at a red heat, setting free the nitrogen and uniting with the oxygen. The layer of metal should fill about 10 cm., and should, ESTIMATION OF NITKOGEN. 355 previously to its use, be ignited and cooled in a stream of dry hydrogen. When the substance contains chlorine, bromine, iodine, sulphur, or phosphorus, it cannot be burnt with cupric oxide. In this case, plumbic chromate must be used, and the first three or four flames must be kept low, so that the end of the tube next to the calcium chloride tube does not become heated to a full red. Estimation of Nitrogen.—In most cases the nitrogen in organic substances can be converted into ammonia (the excep- tions are nitro-compounds and certain organic amides). The substance is heated with soda-lime (a mixture of equal parts of caustic soda and lime), in a tube of difficultly fusible glass, the operation being carried out as in the ordinary combus- tion. Ammonia is evolved and absorbed by leading into dilute chlorhydric acid, and determining the ammonium chloride formed by conversion into platinic ammonium chloride, (NH4Cl)2PtCl4. The ammonia can also be absorbed by a measured amount of a standard acid, and the amount neu- tralized determined by titration with a standard alkali. If the nitrogen is in the form of a nitro-group, it is estimated in the following manner : The substance is burnt, as just described, with cupric oxide and metallic copper, but in the end of the tube, a layer of about 5 cm. of magnesium carbonate is placed. After this follow the layer of cupric oxide, the mixture of the substance with cupric oxide, another layer of cupric oxide, and finally the spirals of metallic copper. The open end of the tube is then closed with a cork through which passes a tube bent as shown in Fig. 4, which passes under the surface of the mercury contained in the bath, and under the end of the eudiometer, or graduated glass tube. On top of the column of mercury in the eudiometer, a layer of a solution of potassium hydroxide is placed. The magnesium carbonate is first heated carefully, till carbonic acid is freely evolved and all the air is expelled from the tube. This is shown by the complete absorption of the bub- 356 APPENDIX. bles by a solution of potassium hydroxide, which is con- veniently contained in a test-tube inverted over the delivery tube. When the bubbles are completely absorbed, the tube is heated, beginning at the delivery-end and proceeding carefully toward the closed end. The gas evolved is received in the eudiometer. When no more gas is given off, the layer of magnesium carbonate is again heated till the bubbles are com- pletely absorbed by the potassium hydroxide soluticn. The gas contained in the eudiometer is pure nitrogen. The eudi- ometer is then placed in a tall vessel filled with water, and after standing some time, the volume of the gas is noted. From the volume of gas thus obtained, its weight is calculated, due observance being made for the temperature, content of moisture, and the pressure of the atmosphere. The formula for calculating the weight of a given volume of nitrogen is P = 0.001256 x V x (B-f) 760 x (1 + 0.003677)^ ESTIMATION OF HALOGENS. obi P denotes the weight of nitrogen sought; V denotes the observed volume of the gas in cubic centimeters ; B denotes the barometric pressure ; / denotes the tension of the vapor of water at the temperature t; t denotes the temperature at the time of the observation ; 0.001256 is the weight of 1 c.c. of nitrogen at 0° C. and 700 mm. baro- metric pressure ; 760 is the normal barometric pressure ; 0.00367 is the coefficient of expansion for a gas for one degree Centt- grade. Chlorine, Bromine, and Iodine are estimated by two methods. 1) The substance is mixed with pure caustic lime and ignited in a short combustion tube. The mass, after cooling, is diffused in water and dissolved in nitric acid, the solution filtered, and the halogen precipitated and weighed in the form of its corresponding silver salt. 2) The substance is heated with twenty to thirty times its volume of concentrated nitric acid and some solid silver nitrate, in a closed tube at 100°- 300° for several hours. The hydrogen and oxygen of the substance are completely oxidized into car- bonic acid and water, while the halogen unites with the silver. After cooling, the tube is opened carefully, the contents washed out with water, filtered, and the insoluble silver chlo- ride, etc., weighed as usual. Sulphur and Phosphorus are also estimated in two ways. 1) The substance is ignited with a mixture of four parts of sodium carbonate, and one part of potassium nitrate. The sulphur and phosphorus are oxidized, forming sodium sul- phate and phosphate. The sulphuric acid of the sulphate is precipitated as barium sulphate with barium chloride, and the phosphoric acid as ammonium magnesium phosphate with magnesium chloride and ammonia. 2) The substance is heated in a closed tube at 100° to 300° with 20-30 times its volume of concentrated nitric acid. The sulphur and phosphorus are oxidized into sulphuric and phos- phoric acids, and are estimated by the usual methods. 358 APPENDIX. The other constituents of organic compounds are estimated, after the destruction of the organic substance, by the usual methods of analytical chemistry. Fig. 5. It has been stated in the introduction that the simplest way to determine the molecular weight of ^. „ a substance, is to compare the weight of a certain volume of its gas with the same volume of air or hydrogen. As the atomic weight of hydrogen is taken as unity, it is more advisable to com- pare the volume-weights of all substan- ces with it, for the molecular weight is then obtained by_ simply doubling the number found. As pressure and temperature, however, exercise an important influence on the |s expansion of gases, it is necessary to reduce the volume found to 0° and the normal atmos- pheric pressure (760 mm.), and to compare it with hydrogen measured under the same con- ditions. One c.c. of hydrogen at 0° and under 760 mm. pressure weighs 0.0000896 gm. The specific weight of a body is estimated by two methods, viz.: either by determining the volume of a known weight of a substance, or by determining the weight of a known volume of the substance. The first method is carried out in two ways. (1) The ap- paratus consists of a flask c (Fig. 5), in which is placed the tube b of a capacity of about 100 c.c. and about 200 mm. high, which terminates in a glass tube 600 mm. Fig. 7. ESTIMATION OF VAPOR-DENSITY. 359 long and about 6 mm. in diameter, ending in a stopper-neck. About 100 mm. from the end, a tube, a, is fused on. A weighed amount of the substance, sufficient to give not more than 50 c. c. of vapor, is placed in the small tube b, and dropped into the main tube by means of the device shown in Fig. 6. On pressing the wire/ of the support, Hc^h. Gallic acid has the composition, C7H605. By elimination of carbonic acid, pyrogallic acid, C6H603, or C6H3(OH)3, is obtained. Hence gallic acid has the constitution: C H I 1?H)3 U(5±l2 (C02H- This method for the elimination of carbonic acid affords also a method of producing new compounds. All the com- pounds which bear the name of "pyro" have been formed from other substances by elimination of carbonic acid, viz.: pyromucic acid, pyromellitic acid, pyroracemic acid, pyro- catechol, etc. Oxidation frequently affords an insight into the constitution of a substance, and constitutes a second analytical method. The oxidation of an alcohol shows whether it is primary, secondary, or tertiary; for the primary alcohols yield on oxi- dation, aldehydes; the secondary, ketones; and the tertiary are decomposed into acids of lower carbon content. In the same way, the constitution of the ketones can often be ascertained. Ketones are decomposed by oxidation into OXIDATION. 365 acids of lower orders (p. 113), the CO-group remaining with the lesser hydrocarbon rest. Mcthyl-butylketone, CH3~CO~C4H9, yields acetic and bu- tyric acids on oxidation : CH3-CO-C4H9 +30 = CH3-OOOH + C4H80,. Methylbutylketone Acetic acid Butyric acid While the isomeric ketone, ethyl-propylketone, yields only propionic acid : C8H.-C0"C3H, +30 = C2H5"COOH + C3H602. Ethylpropylketone Propionic acid. The aromatic hydrocarbons homologous with benzene, i.e., containing side-chains, are, as a rule, easily oxidized. The whole side-chain breaks off, leaving one carboxyl united with the benzene nucleus. The atom of carbon of the side-chain, which is united to the benzene nucleus, is oxidized to car- boxyl, while the other atoms of the side-chain are oxidized to acids of the fatty series (see p. 231). C6H5"CH3 +30 = C6H5-C02H + H80 Toluene Benzoic acid C6H5"CH2-CH3 +60 = C6H5"C02H + C02 + 2 H20 Ethylbenzene Benzoic acid C6H5-CH2-CH2-CH3 + 50 = C6H5_C02H + CH3_C02H Propylbenzene Benzoic acid Acetic acid + H20. All homologues of benzene having only one side-chain yield benzoic acid on oxidation. In the same way, all homo- logues of benzene having two side-chains give dicarboxylic acids (one of the three phthalic acids) on oxidation. Dimethylbenzene Phthalic acid c«H« I oi:cHs+9 °=°«H* 188:5+co*+3 H*°' Methylethylbenzene Phthalic acid 366 APPENDIX. G«R* \ C2H55 + 12 ° = °6H* | 003H + 3 C08 + 4 H20. Diethylbenzene Phthalic acia The products obtained by the oxidation show clearly, there- fore, the number and nature of the side-chains. The constitution of a substance can often be determined in exactly the opposite way, viz.: by reduction. In this way the sulphonic acids are distinguished from the isomeric alkyl- sulphurous acids. The former yield with nascent hydrogen, mercaptan ; the latter, alcohols and hydrogen sulphide : CH3"S02OH + 6 H = CH3SH + 3 H20 Methylsulphonic acid Methylmer- captan CH3-0_S02H + 6H = CH3OH + 2H20 + H2S. Methyl sulphurous acid Methyl alcohol In a similar manner, the nitro-compounds are easily dis- tinguished by reduction, from the isomeric nitrous esters. The former give amido-compounds, the latter, alcohols : CH3N02 + 6 H = CH3NH2 + 2 H20 Nitromethane Methylamine CH3-0"NO + 6 H = CH3OH + NH3 + H20. Methyl nitrous Methyl alcohol ester There are no other general methods for the determination of the constitution of substances analytically. The constitu- tion of many compounds can, however, be ascertained by con- version into simpler compounds of known constitution. As examples, we may recall uric acid (p. 167), creatine (p. 171), the glucosides (p. 329), the lichen principles (p. 333), etc. The synthetic method for the examination of the molecular structure of compounds consists in starting out from simple compounds of known constitution, and building up from them more complicated substances in such a manner that the reactions can be accurately followed, and the constitution of the bodies formed determined. DETERMINATION OF CONSTITUTION. 367 The synthesis of organic compounds, from their elements, constitutes here a particular class. By passing the vapor of ammonium carbonate, which is easily sublimable, over fused potassium, potassium cyanide is formed. Potassium cyanide is converted by oxidizing agents (minium), into potassium cyanate. Potassium cyanate, on boiling with a solution of ammonium sulphate, is transposed into urea. Ammonium cyanate is first formed and then converted into urea by atomic migration. 2 KCNO + (NH4)2S04 = K2S04 + 2 NH4"CNO. N"H4"CNO = C0/^g8 Urea. Hydrogen sulphide and carbon disulphide, when passed over heated copper form methane : 2H2S + CS2 + 4Cu2 = 4Cu2S+ CH4. By the action of chlorine on methane, methyl-chloride, CH3C1, is formed, from which all the derivatives of methane can be obtained ; from it, also, compounds of higher carbon content can be built up. When electric sparks are passed between poles of carbon in an atmosphere of hydrogen, acetylene is formed. Acetylene, C2H2, treated with nascent hydrogen yields ethylene, C2H4, and ethane, C2H6, from which all the derivatives of ethane can be obtained. By leading acetylene through a red-hot tube, benzene is formed : 3 C2H2 = C6H6, from which an infinity of aromatic compounds can be pro- duced. Synthesis, in its broadest sense, means the artificial produc- tion of an organic compound from another. We shall have occasion later on, under the action of reagents on organic sub- stances, to mention the methods by which it can be effected. 368 APPENDIX. In a stricter sense, we understand by synthesis, the joining together of hydrocarbon rests by means of their carbon atoms. Strictly speaking, the production of ether is not a synthetic process, because the binding of the two rests is effected by oxygen : CH3OH + CH3OH = CH3-0_CH3 + H20. The formation of methyl cyanide from methyl iodide, is, on the other hand, a true synthesis : CH3I + CNK = CH3-CN + KI. The principal methods for the production of compounds rich in carbon from those poor in carbon are the following : 1. The sodium compound of an organic substance is treated with the halogen compound (alkylogen, i.e. chloride, bromide, or iodide), sodium chloride, etc., being formed, and the two rests uniting : CH3Na + CH3Br = CH3-CH3 + NaBr Ethane C2H5Na + CH3Br = C2H6"CH3 + NaBr. Propane A very large number of organic compounds have been pro- duced by this method. By acting with sodium on an ester (compound ether), hydro- gen is set free, and a sodium compound is formed, in which the sodium is united to the carbon atom. The compound thus obtained, when treated with an alkylogen, yields the ester of an acid richer in carbon : 2CH3-COOC2H5 + 2Na = CH3-CO-CHNa-COOC2H5 + C2H5ONa + H2. Ethyl sodiumaceto-acetic ester CH3-CO-CHNarCOOC2H5 + C2H5Br = NaBr + CH3-CO_CH-COOC2H6. C2H5 Aceto-ethylacetic ethylester SYNTHESIS. 369 Potassium hydroxide not only saponifies the acetoacetic , ethylester, but decomposes it according to another reaction. In one reaction, acetic acid and a second acid are formed, while in the other, carbonic acid and a ketone are formed : a) CH3-CO_CH-COOC2H5 + 2 KOH C2HS = CH3"COOK + C2H5-CH2-COOK + C2H6OH. Potassium butyrate b) CH3-CO_CH-COOC2H5 + KOH C2H5 = OHs-CO-CH3-C8H, + C02 + C2H5OH. Methyl-propy 1 -ketone Instead of ethyl bromide, the chloride or iodide of any hydrocarbon, aci-chlorides, bromides, etc., and chlorinated, brominated, etc., esters can be used, so that an almost un- limited series of acids and ketones can be produced. In many cases it is not necessary to make the sodium com- pound, in order to eliminate the halogen and join the rests together, it being sufficient to treat two chlorides, bromides, or iodides with sodium : CH3I + CH3I + Na2 = CH2_CH3 + 2 Nal Ethane CH3I + C2HsBr + Na2 = CH3_C2HS + NaBr + Nal Propane C6HsBr + CH3I + Na8 = C6H5_CH3 + NaBr + Nal Methylbenzene C6H5Br + C2H6Br + Xa2 = CBH5_C2H5 + 2 NaBr Ethylbenzene C6HsBr + C6H5Br + Na2 = C6H5_C6H5 + 2 NaBr. Diphenyl Many hydrocarbons, particularly of the aromatic series, have been obtained in this way. 24 370 APPENDIX. 2. By leading carbonic acid through the sodium compound of a hydrocarbon, the carboxylic acid of the next higher series is formed : CH3Na + C02 = C2H3Na02 = CH3"C02Na. Sodium aaetate By leading carbonic acid over the sodium salt of a phenol, the corresponding acid of the next higher carbon series is obtained : 2C6H5ONa + C02 = C6H4 j gggNa + C6H5OH. Sodium phenoxide Sodium salicylate Analogous to this reaction, is the formation of the corre- sponding aldehyde of a higher carbon scries by digesting the alkaline solution of a phenol with chloroform, the chloroform acting as formic acid in statu nascendi: C6H5OH + CHC13 + 3 NaOH = C6H4(ONa)_CHO + 3 NaCl + 2 H20. Sodium salicylaldehyde In this case, also, it is frequently only necessary to pass the carbonic acid through the bromide or iodide of the hydro- carbon in presence of sodium : C6H5Br + Na2 + C02 = C6H5"OOONa + NaBr. Sodium benzoate 3. The halogen derivatives of the hydrocarbons of the fatty series, or the sulphonic acids of the aromatic series, when dis- tilled with potassium cyanide, yield the cyanide of the hydro- carbon. In this case also, the union is through carbon. These cyanides, on boiling with potassium hydroxide, are converted into the acids, the CN-group passing into the COOH-group : CH3I 4- KCN = CH3~CN + KI. CH3"CN + 2H20 = CH3-008H + NH3. Acetic acid SYNTHESIS. 371 CH3Br ft^MT CH2"CN • * + 2KCN=. 3 +2KBr. CH2Br CH2"CN Ethylene bromide Ethylene cyanide CH2"CN ,TT^ CH2"C02H ft>TTT ■ 2 +4H20=. 2 2 +2NH3. CH2"CN 8 CH2-C02H 3 Ethylene cyanide Succinic acid 4. The action of the zinc compounds of the hydrocarbons on the alkylogens is analogous to that of the sodium com- pounds : COCl2 + Zn<^3 _ ZnCl2 + COy ? Ac CH or 2 COCl2 + Zn^gga _ ZnCl3 + 2 COCrCH, Phosgen Zinc methyl Acetyl chloride /OZnCH3 also a) CH3_COCl + Zn(CH3)2 = CH3_C^CH3 /OZnCH3 b) CH3"C^CH3 + Zn(CH3)2 \ci OZnCH3 Not! = CH3_C(-CH3 + ZnCH3Cl '3 /OZnCH3 c) CH3"C^CH3 +2H20 \CH = CH3-C(OH)<^^» + Zn(OH)2 + CH4 Trimethylcarbinol 5. In the presence of aluminic chloride, the aromatic hydro- carbons unite with the chlorides derived from the alcohols with evolution of chlorhydric acid, forming new hydrocarbons : 372 APPENDIX. C6H6 + CH3C1 = HCl + C6H5CH3 C6H6 + 2 CH3Cl = 2 HCl + C6H4(CH3)2 C6H6 + 3 CH3C1 = 3 HCl + C6H3(CH3)3 etc. 6. Aromatic compounds unite with aldehydes in the pres- ence of concentrated sulphuric acid, forming substances richer in carbon : 2 C6H6 + CH3_CHO = H20 + CH3_CH(C6H5)8, etc. % Diphenylethane 7. Salts of organic acids (the lime salts are best) when sub- mitted to dry distillation, either alone or with the salts of other organic acids, afford ketones richer in carbon : 2CH3C02Na=gg3\cO + Na2C03. Sodium acetate Acetone CH3_C02Na + C2H5_C02Na = °^ \cO + Na2C03. Sodium acetate Sodium propionate * Methyl-ethyl ketone As a peculiar kind of synthesis, condensation may be men- tioned. Condensation is the union of two or more molecules of one or more substances by means of their carbon atoms, accompanied by the elimination of water. Aldehydes and ketones, in particular, exhibit this reaction. Aldehyde, C2H40, when treated with weak dehydrating agents {e.g., chlorhydric acid), is converted into Crotonic aldehyde, C4H60 : 2C2H40 = C4H60 = CH3-CH=CH_CHO + H20. Benzaldehyde, C6H5~CHO, and aldehyde, in a similar man- ner pass into cinnamic aldehyde, C9H80 : C7HcO + C2H40 .= C9H80 = C6H5_CH=CH-CHO + H20. The formation of collidine, OgHjjN, from ethylidene CONDENSATION. 373 chloride and ammonia, also belongs here, although the nascent chlorhydric acid eliminates ammonia : 4 CH3-CHC12 + 4 NH3 = 4 CH3-CH=NH + 8 HCl. Hypothetical body 4 CH3"CH=NH = CgH, ,N + 3 NH3. Collidine Acetone yields with chlorhydric acid the condensation-pro- ducts, mesityl oxide, C6H]0O, and phorone, C9H140 : 2C3H60= CpH10O + H2O. Acetone Mesityl oxide C3H60 + C6H10O = C9H140 + H20. Acetone Mesityl oxide Phorone Phorone does not yield further condensation products by an elimination of water ; the hydrocarbon, mesitylene, C9H12, is formed (p. 266). The formation of rosolic acid by the oxidation of a mixture of phenol and salicyl aldehyde, rosanilines by the oxidation of a mixture of aniline and toluidine, and the phthaleines (p. 264) by the action of phthalic anhydride on phenols at an elevated temperature, or in presence of sulphuric acid, belong to this class. Polymerization, although not properly a form of synthesis, should be mentioned under the head of condensation. It con- sists usually in three molecules of a simply constituted body uniting to one molecule. When the carbon atom of a com- pound is united by more than one bond to a polyvalent atom, this binding can be dissolved to a simple one, and the molecules thus having free attractive energies, unite among themselves to one molecule. Aldehydes, cyanic acid, CONH, and its derivatives, and cyan chloride yield, in particular, polymerization-products. Methaldehyde, CH20, (p. 29) passes into methyl metalde- hyde (C6H1206?), the constitution of which is probably : 374 APPENDIX. H gives H2C"0"CH2"0"CH2 H"C=0 6 6 Methyl aldehyde H^O-CH^O"^. Methyl metaldehyde Ethyl aldehyde yields the trimolecular paraldehyde, and probably also the hexamolecular metaldehyde. The constitu- tion of metaldehyde is the same as that of methyl metaldehyde, except that in one an H of a CH2 is replaced, by a CH3. The constitution of paraldehyde is : CH "CHO gives H2C"CH"0"CH"CH3 Aldehyde ■ ■ O'CH-0 CH3 Paraldehyde Cyanic acid passes into the trimolecular cyanuric acid : CONH gives HN=C_0-C=NH Cyanic acid i ' 0_C"0 II NH Cyanuric acid Liquid cyan chloride yields solid cyan chloride: C=NC1 gives CrC=N-C_Cl Cyan chloride I >l (liquid) N=C"N CI Solid cyan chloride Two molecules, probably, of cyanamide polymerize to di- eyanamide : N=C"NH2 gives HN=c/^T>C=NH. Cyanamide Dicyanamide The polymerization of three molecules, forms melamine, C,H«Nfi : ACTION OF REAGENTS. 375 C=N NH0-C=N"C"NH, NH2 Cyanamide N=C"N NH2 Melamine The constitution of the isomeric cyanuric acid may be analogous to that of melamine: HO-C=N-(TOH i u N=C"N OH It has not been ascertained whether the cyanuric acid known has this formula, or whether its nitrogen binds single molecules together. If we accept this formula, we can deduce a number of compounds which stand between cyanuric acid and melamine, and which can be supposed to be derived from each other by substitutions of the OH by NH2, viz., cyanuric acid, C3H3N303, melanuric acid, C3H4N402, ammeline, C3H5N5O, and melamine, C3H6N6. H0"C=N N CTOH 11 11 HO-CTN Cyanuric acid HO"C=N N C-NH3 11 11 H2N-(TN Ammeline HO"C=N N CTNH, 11 11 HO-C"N Melanuric acid H2N"C=N N C"NHa 11 11 H2N"C-N Melamine Action of Reagents on Organic Compounds. As the ordinary reagents usually act on organic com- pounds in a characteristic manner, it is possible to establish certain rules for their action. 1) Chlorine, Bromine and Iodine, act substitutingly: CH4 + CI. = CHSC1 + HCl CRH6 + Br2 = C6H5Br + HBr. 376 APPENDIX. It is necessary, however, in the case of iodine, to destroy at once the iodohydric acid which is formed, else it will cause an inverse substitution, and thus prevent the substitution by the iodine. It is therefore necessary in cases where iodine is to be introduced directly, to add nitric acid, or iodic acid, if the former disturbs the reaction, in order to at once decom- pose the iodohydric acid, which is formed, into iodine: HI03 + 5 HI = 3 I2 + 3 H20. In unsaturated compounds, i.e., in those which contain at least two carbon atoms united by a double binding, the halo- gens dissolve the double binding before substitution takes place. They add on to the molecule : C2H4 + Cl2 = C2H4C12, i. e.: CH2=CH2 + Cl2 = CH2CrCH2Cl 0,H,+8Cl1=0,He01, (p. 203). In the presence of water, the halogens exert an oxidizing action (chlorine, naturally, being the strongest), as they de- compose the water, setting free the oxygen, which acts on the organic compound: H20 + C12 = 2HCl + 0. 2) Chlor- and Bromhydric Acids replace alcoholic hydroxyls by chlorine or bromine : C2H6(OH) + HCl = C2H5C1 + H20 CH3-CH(OH)-COOH + HBr = CH3_CHBr-COOH + H20 Lactic acid Brompropionic acid OT%H:>°+aHoi=c$$+H*0- Ether They often dissolve the double binding of unsaturated compounds : CH2=CH2 + HCl = CH3_CH2C1. ACTION OF REAGENTS. 377 Iodohydric Acid acts in the same manner, but at an elevated temperature it substitutes inversely, i. e., replaces the substi- tuted haloid by hydrogen : CH2I_COOH + HI = CH3"COOH + I2 Iodoacetic acid Acetic acid It acts particularly in this way on oxygen compounds con- taining hydroxyl, i.e., it reduces them. At a sufficiently high temperature, it produces the saturated hydrocarbon, or it breaks the molecule into molecules of methane : C3H803 = CH2(OH)-CH(OH)_CH2(OH) + 5 HI Glycerol = CH3"CHI"CH3 -h 3 H20 + 2 I2 C.H.oO, + 7 HI = C4H,I + 4H20 + 3 I2 Erythrol Sec. butyl iodide CgH, 20 + 10 HI = 5 CH4 + H20 + 5 I2. Amy) alcohol As the free iodine in this reaction always acts as a weak oxidizer, it must be at once removed. This is effected by the addition of phosphorus, which unites with the iodine to phosphorus iodide, which is at once de- composed by the water into iodohydric acid (acting again) and phosphorous acid. 3) Sulphuric Acid replaces the hydroxyl of the fatty alco- hols by HS04 ; and the hydrogen of the aromatic hydrocarbons by HS03 : C2H6(OH) + HHS04 = C2H5"HS04 + H20. Alcohol Ethylsulphuric acid CfiH5H 4- H(S03)OH = C6H5'SO,H + H20. D ° Benzosulphonic acid Water is always formed during the reaction. It is produced, either from the hydroxyl of the organic compound and the substitutable hydro- gen of the acid, or from the hydrogen of the organic compound and the hydroxyl of the acid. 378 APPENDIX. Sulphuric acid can also substitute both hydroxyls of an alcohol, or two H's of an aromatic compound : 2C2H5OH + H2S04= (C2H5)2S04 + 2H20 Ethyl sulphate 2C6H5H + S02(OH)3 = C6H5-S02"C6H5 + 2H20. Sulphobenzid 4) Nitric Acid forms esters with the alcohols of the fatty series : C2H5OH + N02(OH) = C2HgON02 + H20 Ethyl nitric ester C3H5(OH)3 + 3 N02(OH) = C3H5(ON02)3 + 3H20. Glycerol Glycerol nitric ester With the aromatic compounds it forms substitution-products : C6H5H + N02(OH) = C6H "N02 + H20. Nitrobenzene It acts in the same manner as sulphuric acid, but the differ- ent behavior of the two series is here more apparent. With the alcohols of the fatty series, the S02 and N02 are linked to the hydrocarbon rest by means of oxygen, while with the hydrocarbons of the aromatic series, the binding takes place directly between the nitrogen, or sulphur, and the carbon. Nitric acid, HO"N02 Sulphuric acid, HO"S02"OH Nitric ethyl ester, C2H5"0"N02 Ethylsulphuric acid, C2H5"0"S02"OH Ethyl sulphate, C2Hg"0"S02"0"C2H5 Nitrobenzene, C6H5~N02 Benzenesulphonic acid, C6H5~S02~OH Sulphonezid, C6H5"S02"C6H5. Compounds in which the nitrogen of the NO2-group is bound directly to the carbon are also known in the fatty series, and some of them have been described (p. 105). They ACTION OF EEAGENTS. 379 , are usually formed by the action of silver nitrite on alkylogens. Sulphonic acids of the fatty series are also known, and are obtained by the action of sulphites on the corresponding haloid derivatives (p. 103). 5) Potassium and Sodium Hydroxide decompose the esters when in alcoholic solution : C2H50_C2H30 + KOH = C2H5OH+C2H6K02, Acetic ester Alcohol Potassium acetate and change the alkylogens into hydroxyl derivatives : C2H5C1 + KOH = C2HsOH + KC1. When fused in the solid state with organic bodies, they act as oxidizing agents, substituting oxygen for hydrogen and setting the latter free : C2H5OH + KOH = C8H302K + 2H2. Potassium and sodium hydroxides act at a high temperature as very strong bases, producing acids and uniting with them to salts. They con- vert the aldehydes of the aromatic series into the corresponding alcohols : 2 C6H5-C3H30 -f KOH = C6H5-C3H2K02 + C6H5"C2H50. Cinnamic aldehyde Cinnamic acid Cinnamic alcohol They often effect the resolution of a complicated molecule into several molecules of simple acids : C6H, 206 -f- 6 NaOH = 3 C2Na204 +18 H. Sugar The acids derived from hydrocarbons of the CnH2n series, are decom- posed by NaOH and KOH, the molecule breaking at the point where two carbon atoms are united by a double binding : CH3-CH=CH-COOK + KHO + H20= CH3-COOK+ CH3"COOK + H2. Potassium crotonate Potassium acetate 6) Phosphorus Trichloride, PC13, and Phosphorus Tribrom- ide, PBr3, as well as Phosphorus Oxychloride, POCl3, and Bromide, POBr3, substitute OH by CI or Br : 380 APPENDIX. 3 C2H5OH + PC13 = 3 C2HgCl + PH30 3 C2H5(OH) + POBr3 = 3 C2H5Br + PH304. 7) Phosphorus Pentachloride, PC15, and Bromide, PB;r6, substitute oxygen by Cl2 or Br2, acting like free chlorine : C2H40 + PC15 = C2H,C12 + POCl3. Aldehyde Ethylidene chloride Phosphorus Pentasulphide, P2S5, replaces the oxygen of hydroxyl by sulphur : 5 C2H6OH + P2S5 = 5 C2H5SH + P206 5 CH3"COOH + P2S5 = 5 CH3_COSH + P206. In conclusion we shall mention a phenomenon for which no satisfactory explanation has as yet been Offered, viz., the conversion of organic bodies into isomeric ones by atomic migration. The formation of urea from ammonium cyanate has been mentioned several times. In ammonium cyanate, the carbon is united to the di-valent oxygen forming the rest CO. The two bonds of the CO are satisfied by the two valences of the N, whose third bond is satisfied by NH4 : 0=C=N_NH4. On boiling with water, the double binding of the N to the C is dissolved to a simple one, and the unsaturated group, 0=C~N=, is formed at the moment. In this group, the C i has one free bond, and the nitrogen two. One valence of the C takes the N of the NH4, while two H's of the latter rest sat- isfy the two bonds of the N which is united to the C, forming the compound, 0=C<^-xttt2> carbamide, or urea. When glycerol is treated with chlorhydric acid, two bodies ATOMIC MIGRATION. 381 are formed, dichlorhydrins of glycerol, in which two OH's are replaced by Cl's : CH2OH"CHOH-CH2OH Glycerol CH2CrCHCrCH2OH ) tv ,, , CH2C1-CH(0H)-CH2C1 f Dlchlorhyd™« Both of them yield allyl alcohol with sodium : CH2CrCHCrCH2(OH) + Na2 = CH2=CH-CH2OH -f- 2 NaCl. Hence a shifting, or migration, of the hydroxyl from the middle carbon atom to one of the end carbon atoms must have taken place. 3) Hydrazobenzene, C6H5~NH=NH"C6H5, is easily trans- formed by acids into the isomeric benzidine : C6H4"NH2 C6H4"NH2 Here, again, a rearrangement of the atoms has taken place. The two benzene nuclei have each lost an atom of hydrogen and united with each other, while the binding of the nitrogen atoms has been broken, and the NH has passed into NH2. 4) By elimination of water the glycol, CH2(OH)_CH2(OH), PIT \ should pass into ethlylene oxide, /-,tt2 yO, but, on the con- trary, aldehyde, CH3~CHO, is formed. Hence an 0 has become bound by both its valences to a carbon atom, while an H has shifted to another carbon atom. The secondary and tertiary anilines (methylaniline, dime- thylaniline) on heating to 300° are converted into primary bases, toluidine and xylidine : C6H5NH"CH3, is converted into C6H4(CH3)NH2 C6H6N(CH3)a " « " C6H3(CH3)2NH2. 382 APPENDIX. Hence the methyl-group and a hydrogen of the benzene change places. Mellitic acid C(C02H)6 is converted into hydromellitic acid, C6H6(C02H)6, by the action of nascent hydrogen. This latter compound by heating with chlorhydric acid, passes into isohydromellitic acid. In this case, also, it is only possible to explain the reaction by supposing that the atoms, or atomic groups, wander from one carbon atom to another. There are a great number of bodies which are converted into isomeric compounds at an elevated temperature, but we have not space to mention them. INDEX. Abstnthin, 338. Acetal, 87. Acetaldehyde, 84. Acetamide, 93. Acetanilde, 218, 220. Acetic Acid, 32, 88, 101, 187,190, 263. " Propyl Ester, 192. " Ether, 90. " Benzvl Ester, 237. " Methyl Ester, 192. " Ethyl Ester, 90, 192. " Anhydride, 93, 94. Acetins, 118. Acetoacetic Ester, 92. " " Decomposition of, 92. Acetone, 92, 109. 110, 111, 187, 240. " Condensation of, 266. Acetonic acid. 1S2. Acetonitrile, 60, 94,194. Acetophenone, 233, 241. Acetosulphonic Acid, 95. Acetylacetoacetic Ester, 92. *' Bromide, 93. " Chloride, 93. " Cyanide, 93. " Iodide, 93. " Superoxide, 94. " Urea, 51. Acetylene, 76, 178. " Compounds of, 76. Aci Chlorides, 32, 33, 93, 189, 239. Acid-Albumin, 344. Acids, 23, 24. " Amic, 48. " Basicity of, 239. " Dibasic, 191, -239. " Dibasic, with Alcoholic Hydroxyl, 191. " Distillation of, with Lime, 364. " Monobasic, Dry Distillation of Salts of, 175. " Monobasic, Electrolysis of, 175. " Formation of, 188. " Organic. General Remarks on, 31. " Laws of Substitution in Relation to, 32. " Monobasic, 31, 187, 239. " Oil, 190. " Properties of, 188. " Sulphonic, 195. " Sulphonic, Difference between, and Sulphurous Esters, 199. " Sulphonic, Formation of, 195. " " Reduction of, 207. Acids, Tribasic, 191. " Unsaturated, 190. Aconitine, 327. Acridine, 288. Acrol, 151. Acrole, 123. Acrolein-Ammonia, 31, 54. Acroleine, 123, 269. Acroleine Hydrochloride. 123. Acrylic Acid, 114, 123, 190, 269. Adipic Acid, 191. ^Esculetin, 274, 330. ^Esculin, 330. Alanine, 116.125. Alanturic Acid, 169, 170. Albumin, 343. Acid, 344. " Alkali, 314. Blood, 348. " Coagulation of, 344. Egg, 343, 348. " Reactions of, 343. " Serum, 343. Vegetable, 343, 348. Albuminoids, 342, 348. Albuminous Substances, 342. Alcarsine, 71. Alcohols, 24, 32, 80, 91, 182. " Classification of, 185. " Formation, 181. " General Properties of, 24. " Metallic Derivatives of, 25, 27. " Normal, 129. " Oxidation of, 364. " Primary, 129, 185. " Production of, 184. Secondary, 112, 129, 185 " Tertiary, 129, 185. Aldehyde-resin, 84. Aldehydes, 23, 24, 84, 112, 185. " Characteristics of, 84. " Characteristic Reactions of, 186. " Compounds with Acid Sulphites, S4. " Compounds with Ammonia and Sulphurous Acid, 82. " Condensation of, 186. " Elimination of Water from, 272. Formation, 181,186. " Formation from Acids, 191. " Polymerization of, 186. Syntheses of, 270. Aldehydines, 223. 383 384 INDEX. Aldol, 86. Alizarin, 298, 302. -Blue, 303. Alkali-Albumin, 344. Alkaloids, 317. Alkyl-Halogens, 16. Alkylogens, 24. '' Order of Activity of, 22. Allantoine, 165, 169. Allantoxanic Acid, 165. Al anturic Acid, 169, 170. Allophanic Acid, 51. Alloxan, 165, 166, 167. Alloxanic Acid 165, 166, 167. Alloxantinamide, 168. Alloxantine, 167. Allylacetic Acid, 144. Allyl Compounds, 122. " Alcohol, 184, 269. " Cyanide, 124. " Ether, 122. " Iodide, 120,122. " Isocyanide, 124. " Mustard-Oil, 124. " Sulphide, 311, 125. " Sulphide, Metallic Compounds of, 125. " Sulphocyanate, 124. " -Sulpho-Urea, 124. " Phenyl Alcohol, 269. " Pyrocatechol Monomethylether, 311. " Thiocarbylamine, 124. " Tribromide, 122, 314. " Trichloride, 122. " Tricyanide, 122. Allylene, 108, 178. Dibromide, 108. " Tribromide, 108. Almond-Casein. 348. " -Oil, 152. Aloes, 312. Alo'in, 337. Alorcinic Acid, 337. Alphatoluic Acid, 247,262, 263, 290. Aluminium Chloride, Action on Fatty Chlo- rides, etc., 233. " " Syntheses by Means of, 287, 371. Amarine, 23S. Amber, 1&3. Amber-Oil, 308. Amic Acids, 42, 48. Amides, 41, 48, 91, 93, 239. Amidiu, 159. Amidines, 223. Amido-Acetic Acid, 97, 98. " -Acids, 42. " -Azobenzene, 226, 227. " -Benzene, 215, 223. " -Benzoic Acids, 244. " -Benzoic Amide, 245. " -Benzoic Ethyl Ester, 245. " -Dracylic Acid, 245, 254. " -Ethylsulphuric Acid, 82. " -Group, 42. " -Naphthalene, 296, 299. " -Nitrophenol, 227. " -Oxindole, 282. Amido-Phenol, 227. " -Phenylacetic Anhydride, 282. " -Propionic Acid, 125. " -Salicylic Acid, 253. " -Substitutions of Oxalic Acid, 100. " -Succinic Acid, 136. " .-Toluenes, 257. Amidogen, 42. Amine Bases, 41, 192. Amines, 41, 44. '• Behavior of the Salts of. 46. " Derivation from Acids, 194. " Determination of Degree of, 193. " Primary, 44. " Primary, Formation of, 47. " Secondary, 44. " " Formation of, 47. " Tertiary, 44. " " Formation of, 47. Ammeline, 66. Ammonia, Compounds with Aldehyde and Sulphurous Acid, 82. Ammonium Bases, 193. " " Decomposition on Dis- tillation, 193. " " Formation of Substi- tuted, 47. " Cyanate, 63. " Derivatives, 41. " Formate, 34. " Hydrogen Oxalate, 99. " Hydrogen Tartrate, 137. " Mucatc, 316. " Sulphocyanate, 64. Amygdalic Acid, 330. Amygdalin, 329. Amyl Alcohol, normal, 141, 182. ordinary, 142,182. " -Amine, 193. " -Benzene, 291. " Bromide, normal, 141. " Chloride, normal, 141. " Chloride, ordinary, 142. " Dimethylbenzene, 291. " Glycerol, 184. " Glycol, 184. " Iodide, normal, 141. " Iodide, ordinary, 142. " Methylbenzene, 291. " Series, 141. " Xylene, 291. Amylene, 177. Hydrate, 142. Amyloid, 162, 349. Anethol, 311. Angelic Acid, 144, 190. Angelica-Root, 144. Anhydrides, 32, 93, 188, 239. Anilides, 222. Aniline, 215, 223, 280, 281. " Acetate, 220. " Action of Alkylogens on, 216. " Action of Reagents on, 216. " Alkyl Derivatives, 216. " Ammonium Compounds of, 216. -Black, 260. " -Blue, 259, 260. INDEX. 385 Aniline Colors, 257. " Derivatives of, 216. " Double Salts, 216. " Hydrochloride, 216. " Nitrate, 216. " Oxalate, 216. Oxidation of, 213. " -Sulphonic Acid, 222. Test for, 215. " -Violets, 260. " -Yellow, 226. Anilines, Action of Alcohols on, 216. " Secondary, 217. " Substituted, Atomic Migration in, 217. " Tertiary, 217. Animal Casein, 343. Life, 30, 350. Anise-Aldehyde, 311. Anise-Oil, 254, 309, 311. Anisic Acid, 251, 254, 311. Anisoil, 210, 237. Anisyl Alcohol, 251, 254. Aldehyde, 254, 257. Anthracene, 301, 303. " Carboxylic Acid, 302. " Dichloride, 302. Anthraflavic Acid, 304. Anthranilic Acid, 244, 280. Anthrapurpurin, 304. Anthraquinone, 302. " Disulphonic Acid, 302. Anthrachrysone, 304. Antimony Derivatives of Methane, 71. " Potassium Basic Tartrate, 137. Antimonyl, 137. " Potassium Tartrate, 137. Apomorphine, 320. Arabic Acid, 161. Arabinose, 163. Arachidic Acid, 188. Arbutin, 331. Archil, 249. Argol, 136, 137. Aricine, 324. Aromatic Compounds, 195. " " Difference from Fatty, 197. Arrow-root Starch, 160. Arsenic Derivatives of Methane, 70. Dimethyl, 71. Asafoetida, 312. Asparagine, 135. Asparaginic Acid, 342. Aspartic Acid, 136. Asphalt. 313. Atomic Migration, 49, 52, 380. Atropic Acid, 268. Atropine, 326. Sulphate, 326. Azo-Compounds, 223. " -Benzene, 223, 224. " -Benzoic Acids, 244. " -Conhydrine, 318. " -Naphthalenes, 296. " -Prefix, 223. " -Benzene, 223, 224. Azoxybenzoic Acids, 224. 25 Balsam of Peru, 272, 312. " " Tolu, 272, 312. Balsams, 311. Barbituric Acid, 168. Bases, Amine. 192. " Cinchona, 323. " Opium, 320. " Organic, 317. " Pyridine, 313. Basic Hydrogen, 31. '' Lead Acetate, 90. Beeswax, 150. Behenic Acid, 188. Benzal Chloride, 233, 237. Benzaldehyde, 233, 235, 237, 263, 311. Benzamide, 242. Benzene, 196, 202, 240, 264, 287, 291. " Carboxyl Derivatives of, 290. " Derivatives, Isomerism between, 202. " " Reduction of, 275. " Dicarboxylic Acids of, 290. " Direct Replacement of Hydrogen in, 198. " Disubstitutions of, 200. " -Disulphonic Acid, 207. " Hexacarboxylic Acids of, 290. " Hexa-chloride, 203, 277. " Hydroxyl Derivatives of, 212. " Monocarboxyl Derivatives of, 290. " Monoderivatives of, 197. " Monohydroxyl Derivatives of, 298. " Nucleus, 230. " Pentacarboxylic Acids of, 290. " -Sulphamide, 207. " -Sulphochloride, 207. " -Sulphonic Acid, 206. " Symmetrical Substitutions of, 209, " Tetracarboxylic Acids of, 290. " Tetra-substitutions of, 202. " Tricarboxylic Acids, 290. " Trihydroxyl Derivatives of, 289. " Tri-substitutions of, 201. " -Trisulphonic Acid, 207. Benzhydrol, 241. Benzidine, 224, 287. Benzil, 238. Benzilic Acid, 238. Benzine, 180, 203. Benzoic Acid. 233, 235, 239, 243. 262- 263, 290. Anhydride, 242. Benzyl Ester, 237. Ethyl Ester, 243. Methyl Ester, 243. Phenyl Ester, 243. Benzoin, 238. Benzoin Resin, 312. Benzonitrile, 227. " Phenone, 233,240, 241. " Propionic Acid, 268. " Trichloride, 240, 242. Benzoyl-Piperidine, 328. '• -Acetic Anhydride, 242. " Bromide, 242. " Chloride, 241. " Cyanide, 247. 386 INDEX. Benzoyl-Glycocoll, 247. " -Glycollic Acid, 248. " Iodide, 242. Benzsulphaldehyde, 237. Benzyl Acetic Ester, 237. " Alcohol, 233, 235, 236, 246. " Alcohol, Derivatives of, 246. " -Aldehyde, 236. " -Amine, 257. " -Amine Hydrochloride, 247. " Benzoic Ester, 237. •' Chloride, 232, 236. " Cinnamic Ester, 237,272. " Cyanide, 247. " Dichloride, 232. " Disulphide, 247. " Ether, 236. " -Phenyl Ketone, 238. " -Phosphine, 247. " -Pinacoline, 238. " Sulphhydrate, 247. " Sulphide, 239, 247. Berberine, 327. Bergamot-Oil, 308. Betaine, 105. Betaorcinol, 250, 334. Betulin, 338. Bile, 339. Biliary Substances, 339* Bilif uscin, 341. Bilihumin, 341. Biliprasin, 341. Bilirubin, 341. Biliverdin, 341. Binoxalate of Potash, 99. Birch-Bark, 338. Bismuth Valerianate, 143. Bitter Almond-Oil, 237, 309,311. Bitter Principles, 337. Biuret, 50, 51. Bleaching, 333. Blood-Albumin, 348. " -Fibrin, 348. " Test for, 346. Borneo-Camphor, 306. Borneol, 306. Borneol Chloride, 306. Brasilein, 335. Brasilin, 335. Brnzil-Wood, 335. Bromal, 88. Hydrate, 88. Bromanilines, 222. Brom-Benzoic Acids, 244. " -Cyan, 59. " -Hydric Acid, action of on organic compounds, 376. " -Hydrin, 120. " -Malic Acid, 278. " -Meth}'l, 16. " -Naphthalene, 295. " -Nitromethane, 66. " -Malophtlialic Acid, 278. " -Styrolene, 271. Bromine, action of on organic compounds, 375. " Compound with Ether, 84. " Estimation, 357. Bromides of the Hydrocarbons, general re- actions of, 20. Bromoform, 18, 19. Brucine, 325, 326. Butane, 126,174. " Compounds, 126. Butter, 150, 151. Butyl Alcohol, 127, 128, 130, 182. Iso, 128. " " Mustard-Oil of the Second- ary, 311. Secondary, 128, 129, 130, 182. " " Tertiary, 129. " -Aldehyde, normal, 319. " -Amine, 140, 193. " -Benzene, 230, 275, 291. " -Carbinol, 141. " " Secondary, 142. " Chloride, Iso-, 127. " " Normal, 126. " " Pseudo, 126. " " Secondary, 126. " " Tertiary, 127. " Cyanide, 194. " Ethyl Ether, 184. " Glycols, 132,184. " -Glycollic Acids, 132. " -Glycerol, 138. " Iodide, Iso-, 127. " Normal, 127. " " Secondary, 127,128. " " Tertiary, 127. " Isocyanide, 194. " -Lactic Acids, 190. " -Methyl Carbinol, 183. " -Methylketone, 113. Butylene, 177, 178. Butyraldehyde, 186. Iso, 131. " Normal, 131. Butyric Acid, 92, 131, 134, 187,190. ,{ -Methyl Ester, 192. Butyrin, 131. Butyronitrile, 194. Cacodyl, 71. Cacodylic Acid, 71. Oxide, 71. CaffeTc Acid, 273. Caffeine, 171. Caffetannic Acid, 273. Cajeput-Oil, 308. Calcium Butyrate, 132. " Camphorate, 307. Citrate, 147. Isobutyrate, 132. " Oxalate, 99. Tartrate, 137. Camomile-Oil, 309. " " ' Roman, 144. Camphene, 309. '• Inactive, 310. Campholic Acid, 306, 307. Camphor, 3<>6. " Group, 305. " -Oil, 308. INDEX. 387 Camphoric Acid, 306, 307. Camphors, Constitution of, 307 Candles, Stearine, 149. Cane-Sugar, 157. Cantharidin, 338. Caoutchouc, 313. Capric Acid, 149,188. Caproic Acid, Normal, 187, 190. Aldehyde, 186. Capronic Acid, 145. Capryl Alcohol, 148. Caprylic Acid, 148, 188. Caraway Oil, 309, 310. " " Roman, 310. Caramel, 154, 158. Carbamic Acid, 48. Carbamide, 49. Carbaminic Acid, 48. Carbanilamide, 219, 220. Carbanile, 220. 221. Carbanilic Acid, 220. Carbanilide, 219, 220. Carbazol, 288. Carbhydrates, 145, 153. Carbimide, 62. Carbinois, 22, 23,130. " General Properties of, 24 Carbolic Acid, 207. Carbon Disulphide, 36. " Estimation, 2, 351. " Oxysulpbide, 37. " Sulphochloride, 38. " Tetrachloride, 20. Carbonic Acid, 35. " " Hypothetical, 48. " " Substitution-products of, 35. Carboxyl, 31. " Introduction by means of Chlor- carbonic Methyl Ester, 35, 38. Carboxylic Acids, 31. " " Syntheses of, 36,370. Cardamom-Oil, 308. Carminic Acid, 336. Carmine-Red, 336. Carnine, 170. Carotin, 338. Carrots, 338. Carthamin, 335. Carvolj 310. Cascarillin, 339. Casein, 343, 345. " Almond-, 348. " Animal-, 343. Fibrin-, 345. " Legumin-, 348. " Milk-, 348. Castor-Oil, 152. Catechin, 255. Catechol, 212, 289. " Monomethyl Ether of, 212. Cellulose, 161. Cerotic Acid, 150, 188. Cerotic Ceryl Ester, 150. Cerotyl Alcohol, 184. Ceryl Alcohol, 150. " Cerotic Ester, 150. Cetrarin, 338. Cetyl Alcohol, 150, 184. Cheese, Putrid, 143. Chelidonine, 329. Chinese Wax, 150. Chinovic Acid, 325. Chinovin, 325. Chlor-Acetanilide, 222. " -Anilamide, 213. " -Anile, 213. " -Anilic Acid, 213. " -Anilines, 222. " -Benzoic Acid, 243. " -Brombenzene, 206. " -Bromhydrins, 120. " -Carbonic Methyl Ester, 35. " -Carbonous Oxide, 35. " -Carbonyl, 35. " -Cyan, 59. " -Dracylic Acid, 243. " -Ethidene, 77. " -Ethylidene, 77. " -Hydric Acid, Action of, on Organic Compounds, 376. " -Methyl, 16. " -Oxalethyline, 101. " -Oxynaphthalinic Acid, 298. " -Picrine, 66. " -Salicylic Acid, 243. " -Toluenes, 234, 236. " -Toluenes, Action of Chlorine on, 234. Chloral, 86. " Alcoholate, 87. '• -Cyanhydrate, 88. " Hydrate, 87. Chloroform, 18, 95. Chlorophyll, 337. Chlorides of the Hydrocarbons, General Reactions of, 20. Chlorine, Action of ,on Organic Compounds, 375. " Bleach, 333. " Derivatives of Oxamide, 101. " Estimation, 2, 357. Cholesterin, 341. Cholic Acid, 340. Choline, 104. Chondrin, 349. Chondroglucose, 349. Chromogenes, 333. Chrysene, 300. Chrysammic Acid, 337. Chrysaniline, 260. Chrysazin, 304. Chrysene, 304. Chrysin, 338. Chrysoidine, 226. Chrysophan, 304. Chrysophanic Acid, 304. Chrysoquinol, 305. Chrysoquinone, 305. Cinchona Bases, 323. Red, 325. Cinchonidine, 323, 324. Cinchonine, 323, 324. " Sulphate, 324. Cinchoninic Acid, 324. 388 INDEX. Cinnamein, 272, 312. Cinnamene, 271. Cinnamic Acid, 268, 269, 270, 291, 312. Aldehyde, 269, 311. " Anhydride, 271. " Benzyl Ester, 237, 272, 312. " Chloride, 269. " Cinnamyl Ester, 272. " Cinnyl Ester, 269, 312. Cinnamine, 269. Citmamon-Oilj 270, 309, 311. Cinnamyl Amide, 271. Chloride, 271. " Cinnamic Ester, 272. Cinnyl Alcohol, 269. " Cinnamic Ester, 269. " Ether, 269. Citraconic Acid, 146. Citric Acid, 145,191. Clove-Oil, 309, 310. Cocaine, 328. Coccin, 338. Cochineal, 336. Cocoa-nut Oil, 152. Codamine, 320. Codeine, 320, 321. Colchicine, 329. Collidine, 314, 315. Collodion, 162. Colophony, 312. Coloring Matters, 332. Colors, Diazo-, 226. Colubin, 339. Combustion, 351. Comenic Acid, 322. Composition of Organic Substances, Deter- mination of, 351. Compound Ethers, 32. Condensation, 372. Conhydrine, 319. Coniferin, 255, 330. Coniferyl Alcohol, 311. Conine, 318. Constitution, 6. " Analytical Method for Deter- mination of, 363. " Synthetic Method for Deter- mination of, 366. Convolvulin, 332. Convolvulinol, 332. Conylene, 318. Copaiba Balsam, 312. Copaibic Acid, 312. Corydaline, 329. Cotarnine, 322. Cream of Tartar, 137. Creasote, Beech-Wood, 250. " Coal-Tar, 250. Creatine, 171, 173. Creatinine, 172. " Compound with Zinc Chloride, 172. Cresols, 235, 250. Crocin, 356. Crotonic Acid, 124, 139 190. Aldehyde, 86, 139, 270. " Nitrile, 124. Croton-Oil, 144, 152. Crotonylene, 178. Cryptidine, 315. Cryptopine, 320. Crystallin, 344. Cubeb-Oil, 308. Cumaric Acid, 272. " Anhydride, 272. Cumarin, 272. " Homologues of, 273. Cumene, 266, 267, 291. Cumic Acid, 275. " Aldehyde, 275, 310. " Phenol, 306. Cumol, 275. Cupric Acetate, 90. " Ferrocyanide, 58. Curarine, 328. Curcumin, 336. Curled Mint-Oil, 309. Cusconine, 324. Cyan, 65. " -Acetic Acid, 117. " -Ammelide, 66. " -Benzene, 227. " -Butyric Acid, 144. " -Group, 53. " " Isomerism of, 60. " -Hydric Acid, 53, 101. " " " Addition-Product with Glyoxal, 138. " -Hydroxyi, 62. " -Methyl, 60. " -Napththalenes, 298, 299. " -Uramide, 66. " -Uric Acid, 50, 162.. Cyanates, 195. Cyanelid, 62. Cyanic Acid, 62. " " Compounds of, 62. Cyanides, 22, 194. " Formation of, 194. " Reactions with Acids and Alkalis, 62. " Syntheses of, 370. Cyanogen, 65,100,101. Chloride, 59. Cymene, 269, 274, 291, 306, 310. Cymogen, 180. Cymyl Alcohol, 275. Daphnetin, 274, 331. Daphnin, 331. Decatyl Alcohol, 183. Desoxybenzoin. 238. Deuteropine, 320. Dextrine, 159, 161. Dextrose, 154. Dextrotartaric Acid, 138. Di-Acetamide, 94. "-Acetin, 118. "-Aceteylencphenyl, 285. " -Allyliirea, 124. " -Amido-Benzenes, 206, 222. " " -Benzoic Acid, 246. " " -Napththalenes, 299. " " -Phenol, 227. " -Amylamine, 193. INDEX. 389 Di-Basic Acids, 239. " -Benzyl-Amine, 247. " " -Phosphine, 247. " -Brom-Allylamine, 314. " " -Anisoil, 210. " " -Anthracene Tetrabromide, 302. " " -Barbituric Acid, 168. " " -Benzene, 205. " -Methane, 17. " " -Napthalene. 295. •• " -Orthonitrocinnamic Acid, 283. " " -Oxypiperidine, 328. " " ^-Propionic Acid, 124. ■' " -Succinic Acid, 134. "-Butyraldine, 319. " -Carboxylic Acid, of the Butane Series, 132. " Chlor-Acetic Acid, 95. ...... Ethyl Ester, 95. '* -Acetone, 111, 146. " " -Acetonic Acid, 146. " " -Aldehyde, 87. ■• " -Benzene, 204. " " -Benzyl Chloride, 232, 234. .. " " Dichloride, 232. " " -Chrysoquinone, 305. •• " -Dracylic Acid, 233, 334. <« " -Ethene Chloride, 78. » " -Ether, 84. 127. » " -Ethidene Chloride, 78. ■« " -Ethylene, 79. " '* -Ethylene Chloride, 78. " «■ -Ethylidene Chloride, 78. » " -Hydrin. 119. » " -Methane, 17. '• " -Napthalene, 295. » " -Naphthoquinone, 298. « " -Phenol, 209. » •' -Phenylchloroform, 232. » " -Propylene, 108. " " -Quinone, 213. " " -Toluene, 232. 233. " Cyan-Acetonic Acid, 146. " '• -Diamide, 66. " " -Diamidine, 66. " " -Naphthalenes, 299. » " -Ethylacetic Acid, 92. " -Ethyl Aceto-acetic Ester, 92,93. '< " -Amine, 192. » » -Aniline, 216. __ " -Benzene, 230, 268, 274, 291. » « -Carbinol, 142, 182. » " -Urea, 51, 219. " Ethylene-Diamine, 104, 193. _ » >• -Diphenylenediamine, 217. -Glycol, 96. " " -Glycerol, 118. " " -Ketone, 112,187. " " -Oxamide, 101. u " -Phosphine, 105. >> » -Phosphinic Acid, 105. u " -Propyl Carbinol, 183. •i » -Methylcarbinol, 145, 183. ■ t » -Snlphone, 102. « » -Toluidine, 282. _ " -Ethylidenediphenylenediamine, 218 " -Gallic Acid, 256. " -Glycollic Acid, 98. Di-Hydroxy Cinnamic Acid, 273. " " -Ethylidene, 87. " " -Ethylidene Acetic Ester, 87. " " -Naphthalene, 297. " -Iodomethane, 17. " -Isatogen, 285, 286. " -Isopropyl Carbinol, 183. " -Methyl, 75. '• " -Amine, 46, 192. " " -Amylbenzene, 291. " " -Aniline, 216,217. , " " -Anthracene, Tetrahyaroxylated Quinone of, 336. " " -Arsinic Acid, 71. " -Benzene, 230, 233, 261, 279, 287. 291. '• " -Carbinol, 130. " " -Ethylbenzene, 230, 274, 291. " " -Ethyl Carbinol, 142, 182. " " -Hydrazine, 46. " " -Isopropyl Carbinol, 145,183. " " -Ketone, 110. " " -Malonic Acid, 191. " " -Napthalene, 299. " " -Phosphine, 68. " " -Phosphinic Acid, 68. " " -Propyl Carbinol, 145, 183. " " -Pyridine, 314. » " -Urea, 51. " -Xanthine, 171,173. " -Nitro-Amidophenol, 209, 227. " " -Anisoil, 210. " " -Benzene, 206. " " -Benzoic Acid, 244, 246. " " -Benzophenone, 241. " " -Cyanmethane, 67. " " -Diphenyl, 224. " " -Naphthalene, 296. « " -Naphthol, 298. " " -Phenol, 209,227. » « -Oxindole, 281,283. " -Oxy-Anthraquinone, 302. " " -Cumarin s, 274. " -Phenic Acid, 301. " -Phenol, 287. " -Phenyl, 204, 287. " " -Amine, 222. " " -Benzene, 288. " " -Dicarboxylic Acid, 301. " » -Ethylene, 239. " " -Ethylidene, 287. " " -Guanidine, 221. " " -Methane, 288. " " -Thiurea, 219. " " -Tolylmethane, 258. " -Urea, 219, 220. " -Propyl Carbinol, 183. " -Styrolene, 271. " -Sulphocarbonic Acid, 37, 38. " -Tartaric Acid, 136. Dialuramide, 168. Dialuric Acid, 167. Diastase, 155, 344. Diazo-Amido-Benzene, 224, 226. " " -Benzoic Acid, 245. " -Benzene-Anilide, 224. « -Benzene Chloride, 226,227. " -Benzene Nitrate, 225. 390 INDEX. Diazo -Benzoic Acid Nitrate, 245. " -Benzoic Acid Sulphate, 245. " -Benzoic Chloride, 245. " -Colors, 226. " -Compounds, 224. " -Cumene Chloride, 226. " -Diamido-Azobenzene, 226. " -Sulphanilic Acid, 226. Digitalin, 332. Digitalretin, 332. Dilituric Acid, 168. Disacryl, 123. Distilled Verdigris, 90. Drying-Oils, 151. Dulcite, 148. Dulcol, 184. Dutch Liquid, 77. Dyeing, 333. Dynamite, 119. Dyslysin, 340. EGG-Albumin, 343, 348. Elastin, 350. Elaidic Acid, 149. Elecampane-Camphor, 308. Emetine, 329. Emulsin, 150, 330. Eosin, 265. Epichlorhydrin, 120. Ergot of Rye, 159. Erucic Acid, 190. Erythric Acid, 334. Erythrin, 139. Erythrite, 138. Erythrol, 127,138, 184, 334. Erythrol Nitric Ester, 139. Eserine, 328. Essential Oils, 308. Esters, 22, 25, 26, 27, 93, 191. " Action of Alkalis on, 192. " Action of Ammonia on, 192. " Formation, 181,192. " Isomers of, 192. " of Organic Acids, characteristics and formation of, 90. Esters, Sodium Compounds of, 91. Ethaldehyde, 186. Ethoxy-Glycollic Acid, 97. " -Indoxyl, 285. " -Indoxylic Acid, 284. " -Indoxylic Ethyl Ester, 284. " -Nitroso-indoxylic Acid, 284. Ethane, 75, 174. " Derivation from Methane, 74. " Halogen Derivatives of, 77. " Hydroxyl Substitutions of, 80. " Nitrogen Substitutions of, 104. " Sulpho-Substitutions of, 101. Ethene Chloride, 77. Ether, Acetic, 90. " Chlorine Derivatives of, 61. " Compound with Bromine, 84. " Sulphuric, 83. Ethers, 21, 83. Compound, 25, 32,191. " Formation of, 28. " Production of, 185. Ethidine Bromide, 79. Ethol, Pentamethyl, 183. Ethyl Acetate, 90. " -Acetic Ester, 90,116,192. " -Aceto-acetic Ester, 92. " Alcohol, 130, 182. » " Oxidation of, 28, 29. " -Amine, 104, 106, 192. " -Amidobenzoic Ester, 245. " -Aniline, 216. " -Benzene, 230. 261, 291. " -Benzene, Acids derived from, 261. " -Benzene, Phenols of, 261. " -Benzoic Acid, 268. " -Benzoic Ester, 243. " -Bromide, 77. " -Butyl Ether, 184. " -Carbinol, 130. " Chloride, 77. " -Crotonic Acid, 190. " Cj'anic Ether, 106. " Cyanide, 105,194. " Cyanuric Ether, 106. " Dichloracetic Ester, 95. " -Dimethylbenzene, 274, 291. " -Dimethyl Carbinol, 142, 182. " -Diphenyldiamine, 218. " Disulphide, 103, 211. " Ether, 184. " Formic Ester, 48,192. " -Glycol, 184. " -Glycollic Ester, 97. " -Hippuric Ester, 248. " Iodide, 77. " Isocyanide, 106,194. " Isocyanic Ether, 106. " -Lactic Acid; 116. " -Malonic Acid, 144,191. " -Malonic Ester, 117. " Mercaptan, 101, 106, 211. " -Methylacetic Acid, 143. " " Acetamine, 192. " " -Benzenes, 266,291. " " -Carbinol, 127, 130. " " Ether, 84, 1S4. " " -Ketone, 112, 128,131,187. " -Monochlorether, 127. " Mustard-oil, 106. " Nitrate, 83. " Nitric Ester, 83. " Nitrite, 83. " Nitrous Ester, 83. " -Oxalic Acid, 100. " Oxide, 83. " -Phenyl Ether, 210. " -Phosphine, 105. " -Piperidine, 328. " Propionic Ester, 192. " -Propyl Carbinol, 183. " Sulphaldehyde, 103. " Triple Polymer of, 103. " Sulphide, 102, 211. " Sulphocyanate, 106. " -Sulphonic Acid, 102,103,195. " -Urea, 51, 219. " -Vanillin, 336. " -Violet, 259. " -Xylene, 291. INDEX. 391 Ethylene, 75, 177. " Bromide, 78. " Chloride, 77. " Cyanide, 1&3. " Diamine, 104, 193. " -Diphenylenediamine, 217. " -Glycol, 95, 96. " -Glycol Hydrochloride, 114. " Iodide, 76, 79. " Oxide, 76, 96. " -Phenyleneamidine, 223. " -Phenyleneamine, 217. Ethylidene Bromide, 79. Chloride, 77. " -Diphenyldiamine, 217. " Glycol, 115. Eucalin, 159. Eugenol, 311. Euphorbium, 313. Euphorbon, 313. Evernic Acid, 334. Everninic Acid, 334. Fats, 118, 150, 156. " Rancidity of, 151. Fast Dyes, 333. Fecula, 159. Fennel-Oil, 254. 309, 311. Fermentation, 155. Ferments, 155. Ferric Citrate, 147. Ferric Ferrocyanide, 58. Ferrocyan, 55. Ferrous Lactate, 116. Ferulic Acid, 311. Fibriue, 343, 345. Blood, 343, 348. Flesh-, 345. " Gluten-, 345. " Muscle-, 343. Silk-, 350. " Vegetable-, 348. Fibrinogen. 345. Fire-Damp, 15. Flag-Oil, 309. Flavopurpurin, 304. Flesh-Fibrin, 345. Fluoranthrene, 305. Fluorene, 288. Fluorescein, 265. Formanilide, 218. Formamide, 48. Formic Acid, 30, 101, 187. Salts of, 34. " Ethyl Ester, 48. " Isobutyl Ester, 192. " Methyl Ester, 191. Propyl Ester, 192. Formula. Chemical, Derivation of by An- alysis, 3, 5. Frankincense, 313. Frangulic Acid, 304. Franguline, 304. Frn it-Sugar, 157. Fuchsine, 258. Fugitive Dyes, 333. Fulminic Acid, 67. Fulminuric Acid, 67. Fumaric Acid, 139. Furfurole, 317. Fusel Oil, 142, 156. Galactose, 158. Galletn, 265. " Anhydride, 266. Gallic Acid, 214, 256. Gall-Stones, 341. Garlic-Oil, 125. Gentisin, 255. Gliadin, 345. Globulin, 343, 344. Glucosan, 154. Glucose, 154. Glucosides, 155, 163, 329. Glue, 349. " Precipitation by Tannic Acid, 349. Glutamic Acid, 342. Glutaric Acid, 144,191. Gluten, 343, 345. " Casein-, 345. " Fibrin-, 345. Glutin, 349. Glyceric Acid, 120. Glycerides, 149,150. Glycerine, 118. Glycerol, 118, 184. " Nitric Ester, 119. " Oxalic Ester, 118. " Propionic Ester, 119. " Sulphuric Ester, 119. Glycerylphosphoric Acid, 347. Glycine, 98. Glycocholic Acid, 339. Giycocyamidine, 173. Glycocyamine, 172. Glycocyamine-Ilydrochloride, 173. Glycocoll, 97, 98, 164, 244, 248. '• Copper Compound of, 98. Glycogen, 160. Glycollic Acid, 97, 173, 190, 263. " Chloride, 97. Glycolide, 98, 121. Glycol Amide, 97,98. " -Chlorhydrin, 96, 114. " Di-acetyl Ester, 96. " Di-ethyl Ether, 95. " Mono-acetyl Ester, 96. " Monomethyl Ether, 95. " Nitric Ester, 96. Glycols, 95, 184. " Formation, 181. " of the Butane Series, 132. Glycolylurea, 169, 170. Glycvrrhetin, &32. Glycyrrhizin, 332. Glyoxal, 98. " Addition-Product with Cyanhy- dric Acid, 138. Glyoxalic Acid, 98. Glyoxylic Acid, 169. Glyoxylurea, 169, 170. Grape-Sugar, 154. Grass-Bleach, 3:83. Grease-Spot, 150. 392 INDEX. Green Hydroquinone, 214. Guaiacol, 212, 250. Guaiacum Resin, 312. Guanidine, 52,173. Guanine, 171. Gums, 161. Gum-Ammoniac, 312. " -Arabic, 161. " -Benzoin, 240. " -Elimi, 313. " -Galbannm, 312. Gun-Cotton, 162. ' Gutta Percha, 313. H^matein, 335. Haematin, 346. Hematoxylin, 335. Haemoglobin, 343, 346, 348. Halogen Derivatives of Ethane, 77. " " " the Hydrocarbons, 180. Harmaline, 328. Harmine, 328. Helenine, 308. Helleboretn, 332. Helleboresin, 332. Helleboretin, 332. Helleborin, 332. Hemi-Mellitic Acid, 268, 290. " Pinic Acid, 322. Hemp-Oil, 152. Heptane, 175. Heptyl Alcohol, normal, 148,183. Heptylic Acid, 190. Hesperidin, 331. Hesperitin, 331. Hesperitinic Acid, 331. Hexa-Chlorethane, 78. " -Brombenzene, 206." " -Hydrophthalic Acid, 278, 279. " -Hydropyridin, 328. " -Methyl-Benzene, 275, 287. " " Carbinol, 183. Hexane, 175. " Compounds, 145. Hexyl Alcohol, 145. " " Normal, 183. " Butyric Ester, 145. " Iodide, Secondary, 147. Hexylene, 178. Hippuramide, 248. Hippuric Acid, 247, 248. Homologous Hydrocarbons, 176. " Series, 13. Hysenic Acid, 188. Hydantoic Acid, 170. Hydantoine, 169, 170. Hydrazine Compounds, 46, 226. Hydrazo-Benzene, 223, 224, 287. " Benzoic Acids, 244. Hydro-Alizarin, 303. " -Atropic Acid, 268. " -Benzamide, 238. " -Benzoic Acid, 278. " -Benzoin, 238. " -Berberine, 327. " -Caffei'c Acid, 273. Hydro-Cinnamic Acid, 268, 271,291. " -Cobalticyanic Acid, 59. " -Cumaric Acid, 273. " -Cumarin, 273. '« -Cyanic Acid, 53. " -Ferricyanic Acid, 58. " -Ferrocyanic Acid, 57. " -Mellitic Acid, 279. " -Phthalic Acid, 278. " -Pyromellitic Acid, 278. " -Quinone, 212. " " Green, 214, " -Sorbic Acid, 190. " -Terephthalic Acid, 278. " -Umbellie Acid, 274. Hydrocarbons, 12, 20, 174. Action of Chlorine on, 176. Action of Sodium on the Iodo-Compcunds of, 176. Aromatic, Direct Replace- ment of Hydrogen in, 198. Aromatic, Isomers of, 231. Fatty, Direct Replacement of Hydrogen in, 198. Formation from Acids, 33. Formation of, 175. General Reactions of the Chlorides, etc., 20. Halogen Derivatives of, 180. Homologous, 176. Hydroxyl-Substitutions of, 22. Metallo-Componnds of, 195. Metallo-Compoundsof,For- mation of, 195. Normal, 176. Saturated, Formation from Unsaturated, 178. Syntheses of, 369. Union of Unsaturated with Halogens, 178. Unsaturated, 177. Unsaturated, Formation of, 177. Unsaturated, Polymeriza- tion of, 178. Unsaturated, Union with Halogen-Hydric Acids, 178. Unsaturated, Union with Sulphuric Acid, 178. Hydrogen Ammonium Tartrate, 137. " Basic, 31. " Estimation, 2, 351. " Potassium Tartrate, 137. Hydroxybenzoic Acids, 236, 253. " -Butyric Acid, 132. " -Cinnamic Acid, 272. " -Ethylsulphuric Acid, 82. " -Benzene, 207. " -Phenylamido-propionic Acid,342. " -Salicylic Acid, 255,256. Hydroxy], 20. " Derivatives of the Fatty Series, 182. " Substitutions of Ethane, 80. " Hydrocarbons, 22. INDEX. 393 Hydurilic Acid, 168. Hyocholic Acid, 32, 340. " Glycocholic Acid, 340. " Taurocholic Acid, 340. Hyoscyamine. 326. Hypogieic Acid, 190. Hypoxanthine, 170. Icelanb Moss, 338. Icterus, 341. Imides, 42. Imido-Group, 42. Imido-urea, 52. Indican, 279, 282. Indigo, 279. " -Bine, 280, 282, 285, 286. " -Group, 279. " -White, 279, 280, 281, 286. Indigotindisulphonic Acid, 280. Indole, 282, 283. Indoxyl, 285, 286. " Sulphuric Acid, 282. Indoxolic Acid, 284. Indoxylic Ethyl Ester, 283. Inosite, 163. Inverse Substitution, 376. Inverted Sugar, 158. Inulin, 160. Iodides of the Hydrocarbons, General Re- actions of. 20. Iodine, Action of, on Organic Compounds, 375. " Estimation, 2, 357. " Green, 259. Iodo-Anilines, 222. " -Cyan. 59 " -Form, 19. " -Hydric Acid, Action of, 182. ■" -Hydric Acid, Action of, on Organic Compounds, 377. " -Methyl, 17. Isanthraflavic Acid, 304. Isatid, 281. Isatin. 281, 282. Isatinic Acid, 281, 283. Isatogenic Ethyl Ester, 283. Isethionic Acid, 82. Isobutane, 126. Isobutyl Alcohol, 128, 182. " -Amine, 140. -Benzene, 275, 291. " Carbinol, 142. Chloride, 127. " -Dimethyl Carbinol, 183. " Formic Ester, 192. " Iodide, 127. Aldehyde, 128, 131. 186. Iso-Butyric Acid, 128, 131, 132, 187. " -Caproic Acid, 187. " -Crotonic Acid, 139, 190. " -Cyanbenzene, 227, 228. " -Cyanides, 194. " " Formation of, 194. " Disulphocarbonic Acid, 37. " Hydrobenzoln, 238. " -Malic Acid, 136. " -Phthalic Acid, 264, 290. Iso-Picric Acid, 210. " -Propyl Alcohol, 109, 120, 130, 182. " " -Amine, 125, 192. " " -Benzene, 230, 267, 291. " " Bromide, 108. " " Carbinol, 128. " " Chloride, 108. " " Compounds, 107. " " -Dimethyl Carbinol, 145, 183. " " -Glycol, 114, 184. " " -Glycollic Acid, 114. " " Iodide, 107, 108, 120. " " -Methyl Carbinol, 142,182. " " -Methyl-Ketone, 142,187. " -Purpuric Acid, 210. " -Succinic Acid, 133, 134, 191. Isomerism, 9. " between Disubstitutions of Benzene, 200. Itaconic Acid, 146. Jalap, 312. Jalapin, a32. Jalapinol, 332. Jervine, 327. Keratrine, 349. Kerosene, 179. Ketones, 112, 113, 187, 239, 323. " Aromatic, 241. " Condensation of, 187. " Formation of, 187. " Formation of, from Acids, 191. " Mixed, 112. " Oxidation of, 187, 364. " Syntheses of, 372. Koumis, 159. Kyanmethyl, 60. 1