None
M. 23, 64 ; C. 1902, I. 628 ; II. 19 ; 1903, I. 384). (5) Ammonia produces alkylene diamines. (6) Potassium cyanide converts them into the nitriles of monohalogen acids ?&nd of the dicarboxylic acids. These are classes of bodies whose connection with the .glycols is indicated by the dihalogen paraffins : CH2 CH2Br CH, VOL. I. CH2.OH CH2.OH CH2.CN CH2.COOH X, I €H2.CN Ethylene Cyanide. CH2.COOH Ethylene Succinic Acid. Y 322 ORGANIC CHEMISTRY (7) The alkylene dihalides react with magnesium in ethereal solution in part similarly to, and in part in a more complicated manner than, do the simple alkyl halides (p. 185). Ethylene bromide gives ethylene and magnesium bromide ; in the cold BrCH2CH2MgBr is also obtained. Trimethylene bromide forms trimethylene (CH2)3 (p. 321), and also BrMg[CH2]6MgBr, which with CO2 yields suberic acid, HO2C.[CH2]6- C02H. Pentamethylene bromide yields, as expected, BrMg[CH2]5MgBr, and also some BrMg[CH2]1()MgBr. The latter substance, with CO2, gives decane dicarboxylic acid ; the former, pentane dicarboxylic acid (pimelic acid) and hexamethylene ketone (B. 38, 1296 ; 40, 3049 ; C. 1907, II. 681). CO2 BrMg[CH2]6MgBr -> [CH2]6>CO. Pimelic Acid. Hexamethylene Ketone. Ethylene Halides — Ethylene Chloride, Elayl Chloride, Oil of the Dutch chemists, CH2C1.CH2C1, b.p. 84°, D4= 1*2808, can be prepared (A. 94, 245) by conducting ethylene into a gently heated mixture of 2 parts of manganese dioxide, 3 parts of sodium chloride, 4 parts of water and 5 parts of sulphuric acid. It is also prepared from ethylene diamine and NOC1 ; also from dibenzoyl ethylene diamine and PC15 (comp. p. 320). It is insoluble in water, has an agreeable odour, and sweet taste. Ethylene Bromide, CH2Br.CH2Br, m.p. 9°, b.p. 131°, is formed when ethylene is introduced into bromine, contained in a wide con- denser bent at right angles, which is covered with a layer of water (A. 168, 64). It is also produced when ethyl bromide, bromine and iron wire are heated to 100° (B. 24, 4249). Ethylene Iodide, CH2I.CH2I, m.p. 81°, is formed on conducting ethylene into a paste of iodine and ethyl alcohol (J. 1864, 345). History of the Alkylene Halides. — The four Dutch chemists, Deiman, Paets van Troostwyk, Bondt and Lauwerenburgh, while studying the action of chlorine on ethylene, first obtained ethylene chloride in 1795 as an oily reaction product. Hence they called ethylene " gaz huileux," oily gas, a name which Fourcroy altered to " gaz olefiant," " oil-forming gas " (see Roscoe and Schorlemmer, Org. Ch., i, 647). This phrase subsequently gave the name " olefines " to the series. Balard, the discoverer of bromine, obtained ethylene bromide in 1826 by allowing bromine to act on ethylene (A. chim. phys. [2] 32, 375). Faraday, in 1821, prepared ethylene iodide by acting on ethylene with iodine in sunlight. Propylene Halides, i,2-Dihalogen Propane, CH3CHX.CH2X, and Trimethylene Halides, t ,^-Dihalogen Propane, CH2X.CH2CH2X. The propylene halides result from the addition of halogens to propylene, and halogen acids to alkyl halides at 100°. Trimethylene bromide is prepared from ethyl bromide and hydrobromic acid at —20° and, accompanied by propylene bromide, from trimsthylene and bromine in hydrobromic acid (C. 1899, I. 731 ; 1900, II. 465). HgCl, and KI, change trimethylene bromide into the chloride and iodide. Propylene Chloride, b.p. 97°; Trimethylene Chloride, b.p. 119°. ,, Bromide, ,, 141° ; „• Bromide, ,, 165°. „ Iodide, decomposes ; „ Iodide, decomposes. Tetramethyl Ethylene Chloride, (CH8)2CC1.CC1(CH8)2, m.p. 159°, is prepared from pinacone and HC1 (C. 1900, II. 1061). Tetramethyl Ethylene Bromide, m.p. 149°, with decomposition, results from the action of sunlight on Tetramethyl Ethylene Nitrosobromide, (CH3)2CBr.- C(NO)(CH3)2. This substance is prepared from tetramethyl ethylene and NOBr (comp. p. 327) (B. 37, 545). It is a very volatile blue crystalline powder. ESTERS OF THE DIHYDRIC ALCOHOLS OR GLYCOLS 323 i,3-Dibromobutane, CH3CHBr.CH2CH2Br, b.p. 147°, is obtained from <f-butylene glycol (C. 1902, II. 1097). 2,4-Dibromopentane, CH3CHBr.CH2CHBrCH3, b.p.9 63° (C. 1904, I. 1327). Higher Homologues of the Polymethylene Halicle Series are mostly obtained by the general methods of preparation, Nos. 4 and 5 (p. 320) (J. pr. Ch. [2] 39, 542 ; B. 27, R. 735 ; 38, 2346 ; 39, 1112 ; C. 1903, I. 583 ; 1904. H. 429 ; 1905, I. 1698 ; 1906, I. 443). Tetramethylene Chloride, C1[CH2]4C1, b.p. 162° ; bromide, m.p. — 20°, b.p.ia 82° ; iodide, m.p. 5-8°. Pentamethylene Chloride, i,5?Dichloropentane, C1[CH2]BC1, b.p. 177°; bromide, b.p. 221° ; iodide, m.p. 9°, b.p.20 149°- Hexamethylene Chloride, C1[CH2]6C1, b.p. 204° ; iodide, m.p. 9-5°, b.p.17 163°. Heptamethylene Chloride, C1(CH2)7C1, b.p.28 126° ; iodide, m.p. o°, b.p.20 i78°- 2,5-Dibromohexane, CH3CHBr.CH2.CH2.CHBrCH3, is prepared from 2,5- hexylene glycol (p. 315), from A«-hexane-e-ol (butallyl methyl carbinol), or from diallyl (p. 190) by means of hydrobromic acid. A mixture of stereoisomeric forms is obtained, containing a racemic form, m.p. 38°, and the mesoform, a liquid, b.p. 20 100° (B. 34, 2569 ; 35, 1337). Sodium converts these compounds into cycloparaffins (Vol. II.), just as sodium and trimethylene bromide produce trimethylene. Sodium malonic esters, sodium acetoacetic esters, and polymethylene bromides produce cycloparaffm carboxylic esters (Vol. II.). Mixed, neutral halogen esters of the glycols, con- taining two different halogen atoms, are also known. (b) Esters of Mineral Acids containing Oxygen. Ethylene Nitrate, Glycol Dinitrate, C2H4(O.NO2)2, D8=i'483, is produced on heating ethylene iodide with silver nitrate in alcoholic solution, or by dis- solving glycol in a mixture of concentrated sulphuric and nitric acids : C2H4(OH)2+2HO.NO2=C2H4(O.NO2)2+2H2O. This reaction is characteristic of all hydroxyl compounds (polyhydric alcohols and polyhydric acids] ; the hydrogen of hydroxyl is replaced by the N0z-group. The nitrate is a yellowish liquid, insoluble in water. It explodes when heated (like nitroglycerine). Alkalis saponify the ester with formation of nitric acid and glycol. OH Glycol Sulphuric Acid, C2H4<Q SQ QH, is produced on heating glycol with sulphuric acid. It is perfectly similar to ethyl sulphuric acid (p. 139), and decomposes, when boiled with water or alkalis, into glycol and sulphuric acid. B. Esters of Carboxylic Acids. In studying the fatty acids the methods of forming esters with monohydric alcohols were described. The same methods serve for the production of esters of the fatty acids with dihydric alcohols or glycols : (1) from the haloid esters of the glycols : halogenhydrins and alkylene halides with fatty-acid salts : CH2OH CH2OH | +CH3CO2K=| +KC1; CH2C1 CH2OCOCH3 (2) from glycols by means of free acids, acid chlorides or acid anhydrides. (3) There also remains that type of ester formation resulting from the addition of acids and acid anhydrides to alkylene oxides, just as acid anhydrides add themselves to aldehydes : CH2, CH2OCOCH3 | >0 + (C2H30)20=| ; CH/ CH2OCOCH3 CH3CHO + (C2H3O)2O=CH3.CH(OCOCH3)8. Glycol Diformin, C2H4(O.CHO)2, b.p.25 89°, is prepared from glycol by a mixture of formic acid and acetic anhydride (C. 1900, II. 314). Glycol Monacetate, CH2(OH)CH2OCOCH?, b.p. 182°, is a liquid miscible with water. If hydrochloric acid gas be led into the warmed substance there is formed Glycol Chloracetin, Chlorethyl Acetate, CH2ClCH2.O.C2HaO, b.p. 144°. 324 ORGANIC CHEMISTRY Similarly, hydrobromic acid produces Glycol Bromacetate, b.p. 163°, which yields Glycol lodacetin, b.p.60 110°, when treated with Nal (C. 1901, I. 1356). Glycol Diacetate, C2H4(O.C2H3O)2, b.p. 186°, D0 = 1-128. It dissolves in 7 parts of water. Glycol Distearate, C2H4(OCOC17H35)2, m.p. 79°, b.p.0 241°. Glycol Dipalmitate, C2H4(OCOC16H31)2> m.p. 72°, b.p.0 226° (B. 36, 4340). a-Propylene Glycol Diacetate, CH3.C2H3(O.COCH8)2, b.p. 186° ; Trimethytene Glycol Diacetate, (CH2)8(OCOCH,)2, b.p. 210°. The formation of the acid esters is well suited for the detection and deter- mination of the number of hydroxyl groups in the polyhydric alcohols, the sugars and the phenols. Benzoic ester particularly is especially easy to prepare. It is only necessary to shake up the substance with benzoyl chloride and sodium hydroxide in order to benzoylize all the hydroxyls (B. 21, 2744 ; 22, R. 668, 817). The formation of the nitric acid ester is also well adapted for the purpose (see Glycol Dinitrate, p. 323) ; also the carbamic ester resulting from the action of the isocyanic ester (q.v.) ; and especially the phenyl isocyanic ester (q.v.). For carboxylic esters of unsaturated glycols, see p. 315. 3. THIO-COMPOUNDS OF ETHYLENE GLYCOLS Compare the sulphur derivatives of the monohydric alcohols (p. 142), the aldehydes (p. 208), and the ketones (p. 225). A. Mercaptans. The mercaptans corresponding with ethylene glycol are formed by treating monochlorhydrin and ethylene bromide with potassium hydrosulphide. The Monothio-ethylene Glycol, HSCH2.CH2OH, yields isethionic acid (p. 325) when treated with nitric acid. Dithioglycol, Ethylene Mercaptan, Ethylene Thiohydrate, C2H4<|**, b.p. 146°, D=si'i2, possesses an odour something like that of mercaptan. It is insoluble in water, and dissolves in alcohol and ether. It shows the reactions of a mercaptan (B. 20, 461). Trimethylene Mercaptan, HS(CH2)3SH, b.p. 169° (B. 32. 1370). B. Sulphides. (a) A Iky I Ethers of the Ethylene Mercaptans : Hydroxyethyl Ethyl Sulphide, CH,CHt.S.CH2CH2OH, b.p. 184°. Ethylene Dimethyl Sulphide, CH3S.CH,.- CHj.SCH,, b.p. 183°. Ethylene Diethyl Sulphide, b.p. 188°. (b) Vinyl-alkyl Ethers of Ethylene Mercaptan or Sulphurates : Vinyl Ethyl Ethylene Mercaptan, CH2:CH.SCH2CH2S.C2H6, b.p. 214°. For its formation, see the sulphine compounds, which are treated later on. (c) Thiodiglycol, HOCHjCHj.S.CHjCHjOH, corresponding with diglycol, is also known (B. 19, 3259). However, the simple ethylene sulphide, correspond- ing with ethylene oxide, is not known, whilst Diethylene Oxide Sulphone, 2' m-P- I3°°» corresponding with diethylene oxysulphide, as well as Diethylene Bisulphide, are known. PTT _ pur (d) Cyclic Sulphides: Diethylene Disulphide, s<cHl!cH >S' m'P' II2°' b.p. 200°, is formed from ethylene mercaptan, ethylene bromide, and sodium oxide. When ethylene bromide is digested with alcoholic sodium sulphide, a polymeric tthylene sulphide, (C2H4S)», m.p. 145°, is produced at first. This is a white, amorphous powder, insoluble in the ordinary solvents, which protracted boiling with phenol Changes to diethylene disulphide (A. 240, 305 ; B. 19, 3263 ; 20, 2967). Trimethylene Disulphide, CH,< 2- , m.p. 75° (B. 32, 1370). CH2S (e) Ethylene Mercaptals and Ethylene Mercaptols are similarly produced from ethvlene" mercaptan by the action of aldehydes, ketones, and HC1, just as the mercaptals (p. 209) and the mercaptols (p. 226) are obtained from mercaptans (B. 21, 1473). CH2SV Ethylene Dithioethylidene, \ >CH-CHs. b.p. 173*. CH,S/ THIO-COMPOUNDS OF THE ETHYLENE GLYCOLS 325 CHaS— SCH2 (/) Diethylene Tetrasulphide , \ \ , m.p. 150°? is produced by the CH2S— SCH2 action of the halogens, or sulphuryl chloride or hydroxylamine on ethylene mercaptan. It is a white, amorphous powder (B. 21, 1470). C. Sulphine Derivatives. Ethyl iodide and diethylene disulphide unite to form Diethylene Disulphide Sulphine Ethyl Iodide, S<^2^^2>S<f zH*. CJtlf.S«C|Hg Ethyl Sulphurane, | , is produced on distilling the above-mentioned CHa.S.C2H5 iodide with sodium hydroxide. The closed ring of diethylene disulphide is broken. The union of the derivatives of diethylene disulphide with the higher alkyl iodides yields homologous compounds known as sulphuranes. They are the alkyl vinyl thio-ethers of ethylene (B. 19, 3263 ; 20, 2967 ; A. 240, 305). D. Sulphones. The disulphones are produced when the open and the cyclic disulphides are oxidized by potassium permanganate. All sulphones, in which sulphone groups are attached to two adjacent carbon atoms, can be hydrolyzed (Stuffer's law, B. 26, 1125). CH2.S02.C2H6 (a) Open Sulphones : Ethylene Diethyl Sulphone, I , m.p. 137°, CH2.SO2.C2H5 has been obtained (i) from ethylene dithioethyl ; (2) from ethylene bromide by the action of sodium ethyl sulphinate, and (3) from sodium ethylene di- sulphinate by the action of ethyl bromide. The hexivalence of sulphur in the sulphones is thus proved (B. 21, R. 102). (6) Cyclic Sulphones (B. 26, 1124 ; 27, 3043) : Trimethylene Disulphone, m.p. 204-205°, results from the oxidation of methylene dithioethylene. Barium hydroxide solution decomposes this into Hydroxyethyl Sulphone Methylene Sul- phinic Acid. This, on boiling with water, forms first an internal anhydride, b.p. 164°, which then loses SO2 and turns into Hydroxymethylene Sulphone, m.p. 20°. CH2— SO2X CH2OH CH2O . SO CH2OH | >CH2 M M | — >\ ' CH2— SO/ CH2.S02CH2S02H CH2SO2.CH2 CH2SO2CHS Trimethylene Hydroxyethyl Sulphone Hydroxyethyl Sulphone. Methylene Sulphinic Acid. Methyl Sulphone. The sulphinic lactone gives, on oxidation, Hydroxyethyl Sulphone Methylene CH2— O— SO 2 Sulphone Lactone, \ \ CH2.S02.CHa CHa— S0a— CH8 Diethylene Disulphone, \ \ , results from the oxidation of diethy- CH2— Spa— CH2 lene disulphide, and decomposes similarly to trimethylene disulphone. E. Sulphonic Acid. Isethionic Acid, Ethylene Hydrinsulphonic Acid, Hydroxyethyl CH2.OH Sulphonic Acid, \ , is isomeric with ethyl sulphuric acid, CH2.SO3H C2H5O.SO3H, and is produced (i) by oxidizing monothioethylene glycol with HNO3 ; (2) by the action of nitrous acid on taurine or amidoisethionic acid (comp. formation of glycollic acid from glycocoll, p. 362) : HaN.CH2CH2S08H+HONO=HO.CH2CH2SO,H+N8+HtO. 326 ORGANIC CHEMISTRY (3) by heating glycol chlorhydrin with potassium sulphite ; (4) by boiling ethionic acid (p. 327) with water (B. 14, 64 ; A. 223, 198) ; (5) from ethylene oxide and potassium hydrogen sulphite. Isethionic acid is a thick liquid, which solidifies when allowed to stand over sulphuric acid. Its salts are very stable and crystallize well. Chromic acid oxidizes isethionic acid to sulpho-acetic acid. The barium salt is anhydrous ; ammonium salt forms plates, m.p. 135°, and at 210-220° it changes to the ammonium salt of di-isethionic acid, O(CH2.- CH2SO3NH4)2 (B. 14, 65). Ethyl Isethionate, b.p. 120° (see B. 15, 947). PC16 converts the acid into Chlorethyl Sulphonic Chloride, C1.CH2CH2SO2C1, b.p. 200°. It is also formed by heating ethane disulphochloride. When it is boiled with water it is converted into Chlorethyl Sulphonic Acid, CH2Cl.CHa,SO3H (A. 223, 212).. Taurine, Aminoisethionic Acid, Aminoethyl Sulphonic Acid, CH2NH, CH2.NH3 1 , or | | , m.p. about 240°, with decomposition, was CH2.S03H CH2.SO? discovered by Gmelin in 1824 > its sulphur content, which had previously been overlooked, was detected in 1846 by Redtenbacher. It is considered in this connection because of its intimate relationship to isethionic and chlorethylene sulphonic acids. It occurs as tauro- cholic acid, in combination with cholic acid, in the bile of oxen (hence the name — ravpos, ox) and many other animals, and also in the different animal secretions. It is formed when taurocholic acid is decomposed with hydro- chloric acid : CH2.NH(C24H3904) CH2SO3H Taurocholic Acid. HC1 H»0 CH2.NH2 ) +C24H400§. CH2.SO3H Taurine. Cholic Acid. It can be prepared artificially by heating chlorethyl sulphonic acid, CH2C1CH2SO3H, with aqueous ammonia (Kolbe, 1862, A. 122, 33). This synthesis presupposes that of ethylene or ethyl alcohol (p. in). Both substances combine with SO3 to give carbyl sulphate, a derivative of isethionic acid. The following diagram shows the course of the synthesis : CH2.OH 2S03 CH2.OS02X H20 CH2.O.S03H CH8 Alcohol. >0 CH2.S02 ' Carbyl Sulphate. CH2SO3H Ethionic Acid. CH2.OH .SO,H Isethionic Acid. CH2.C1 H2o CH2.C1 NH, CHj.NH, CH2SO2C1 Chlorethyl Sul- phonic Chloride. CH2.SO2OH Chlorethyl Sulphonic Acid. CH2.SQ,H. Taurine. Taurine also results when ethylenimine is evaporated together with sulphurous acid. Taurine crystallizes in large, monoclinic prisms, insoluble in alcohol, but readily dissolved by hot water. It contains the groups NH2 and SO3H, and is, therefore, both a base and a sulphonic acid, but as the NITROGEN DERIVATIVES OF THE GLYCOLS 327 two groups neutralize each other, the compound has a neutral reaction. It may, therefore, be considered as a cyclic ammonium salt, as indicated in the second constitutional formula. It can form salts with the alkalis. It separates unaltered from its solution in acids (see Glycocoll). Nitrous acid converts it into isethionic acid (p. 325). Boiling alkalis and acids do not affect it, but when fused with potassium hydroxide it breaks up according to the equation : CH2— NH Anhydrotaurine, \ \ , m.p. 88°, is formed by the action of ammonia CH2— SO 2 on chlorethane sulphochloride, or on ethane disulphochloride (C. 1898, I. 20). Taurine introduced into the animal economy reappears in the urine as Tauro- carbamic Acid, NH2CONH.CH2.CH2.SO8H. CH2 - N(CH,)3 Taurobetaine, \ , is prepared by methylating taurine, and is CH2— SO2O analogous to betai'we (q.v.). Ethionic Acid, C2H4<gQS^-3H. The constitution of this acid would indicate it to be both a sulphonic acid and primary sulphuric ester.. It is therefore dibasic, and on boiling with water readily yields sulphuric and isethionic acids. It results when carbyl sulphate takes up water. CH2— O— SO2X Carbyl Sulphate, \ )O, the anhydride of ethionic acid (A. 223, 210), CHa - SO/ is formed when the vapours of SO3 are passed through anhydrous alcohol. It is also produced by the direct union of ethylene with two molecules of SO3. CH2.S03H Ethylene Disulphinic Acid, Ethane Disulphonate, \ , m.p. 100°, may CH2.SO,H be prepared from glycol mercaptan and ethylene thiocyanate by means of con- centrated nitric acid ; by the action of fuming sulphuric acid on alcohol or ether ; or by boiling ethylene bromide with a concentrated solution of potassium sulphite. It is easily soluble in water. Reduction with zinc dust, see B. 38, 1071. Ethane Disulphochloride, SO2C1.CH2.CH2.SO2C1, m.p. 98°, by the action CH2SO2H of zinc dust, forms the zinc salt of Ethylene Disulphoinic A cid, \ . The CH2S02H disulphochloride, similarly to the homologous chloride of i,2-Propane Disulphonic Acid, CH3CH(SO2C1)CH2SO2C1, m.p. 48°, easily gives up SO2 (comp. p. 147, Anhydrotaurine, Vinyl, and Propenyl Sulphonic Acid) ; whilst the chloride of Trimethylene Disulphonic Acid, CH2(CH2SO2C1)2, is more stable (B. 34, 3467 ; 36, 3626), and behaves in accordance with Stuffer's rule (p. 325). 4. NITROGEN DERIVATIVES OF THE GLYCOLS A. Nitroso-eompounds. The addition-products of the defines with nitrosyl chloride belong to this group (comp. the Terpenes, Vol. II.). Tetramethyl Ethylene Nitrosyl Chloride, (CH3)2C(NO).CC1(CH3)2, m.p. 121°, is prepared by adding sodium nitrite to tetramethyl ethylene in an alcoholic solution of hydrochloric acid in the cold (B. 27, 455 ; R. 467). It has a blue colour, and a somewhat penetrating camphor-like odour. See also Trimethyl Ethylene Nitrosite, (CH3)aC(ONO).CH(NO)CH8, and Ni- trosate, (CH3)2C(ONO2).CH(NO)CH3 (p. 345). B. Nitro-compounds. Only one nitro-derivative of glycol — the primary body — is known. The mononitro- compounds can be looked on as being nitro-substitution products 328 ORGANIC CHEMISTRY of the paraffin alcohols, and are known under the name of nitro-alcohols. They are prepared by the interaction of the halohydrines and silver nitrite, and from the primary mononitro- paraffins by condensation with aldehydes by means of a dilute solution of potassium bicarbonate or alkali hydroxide (C. 1899, I. 1154). Nitroethyl Alcohol, Glycol Nitrohydrin, CH2(NO2).CH2.OH, b.p.3, 120°. is a heavy oil. 2-Nitropropyl Alcohol, CH3CH(NO2)CH2OH, b.p.2a 121°. Nitroisopropyl Alcohol, CH8.CH(OH)CH2NOa, b.p.80 112°, D18 = i-i9i (B. 28, R. 606) (see also Nitro-olefines, p. 151). $-Nitropropanol, HO.CH2.CH2.CH2NO2, b.p.M 139°. For nitro-alcohols containing 4,5, and 6 carbon atoms, see C. 1897, II. 337 ; 1898, 1. 193. ForDinitro- and Halogen-nitro-compounds, corresponding with the glycol series, see pp. 151, 155. C. Amines and Ammonium Compounds of the Glycols. There are two series of amines, derived from the glycols, and corresponding with the two series of glycollates, esters, mercaptans, etc. : HO.CH2CHa.OH, HO.CH2CH2.NH2, and NH2.CH2CH2.NHt. Glycol. Hydroxyethylamine. Bthylene Diamine. Therefore the amines of the glycols fall into two classes : (i) The hydroxyalkylamines and their derivatives ; (2) the alkylene diamines and their derivatives. (a) Hydroxyalkyl Bases, or Hydramines and their derivatives. — Methods of formation : (i) action of ammonia on the halohydrins ; (2) by the union of ammonia and alkylene oxides in the presence of water (B. 32, 729; C. 1900, II. 1009). In these two reactions the products are primary, secondary, and tertiary hydroxyalkyl bases, e.g. : CHX\ CHj.OH CH CH ;f\ CH2.OH >O+NH.= | Hydroxyethylamine or Aminoethyl Alcohol (p. 117). / CH2.NH2 V^nj| CHav CHt(OH).CH2\ 3 I >O+NHs=CH2(OH).rH AN Trihydroxyethylamine or Azoethyl Alcohol. CH/ CH2^OH).CH2/ These three bases are best separated by distillation under reduced pressure (B. 30, 909). They were discovered by Wtirtz and closely investigated by Knorr. (3) by reduction of nitro-alcohols (see above) hydroxyacid nitriles, amino-ketones or isonilroso-ketones (B. 33, 2829, 3169) ; (4) by the action of sulphuric acid on allylamine with addition of water (B. 16, 532) : (5) by the application of the phthalimide reaction (p. 159). Alky- lene halides are allowed to act on potassium phthalimide, the re- action-product being heated with sulphuric acid to 200-230° : On the course of the reaction of the alkaline decomposition of the bromalkyl phthalimides, see B. 38, 2404. (6) The dialkylated hydroxyethylamine bases are also known as alkamines, and their carboxylic esters as alkemes (such as tropeme) (B. 15, 1143). Alkamines are obtained from the halogen hydrines and NITROGEN DERIVATIVES OF THE GLYCOLS 329 secondary amines ; also from dialkyl amino-acetic esters and mag- nesium alkyl halides (B. 39, 810) : CaH6MgI (C2H6)2N.CH2.COOC2H5 - — > (C2H5)2N.CH2C(C2H6)2OH. Some are possessed of physiological action (comp. C. 1904, I. 1195 ; 1906, I. 1584). ydroxyethylamine bases are separated by fractional crystallization of 1 salts, or platinum double salts. They are thick, strongly alkaline The h their HC1 liquids, which decompose upon distillation. Hydroxyethylamine, Amino-ethyl Alcohol [Aminethane-2-ol] [Ethanolamine], CH2(OH)CH2NH2, b.p. 171°, and the homologous series of the Hydroxyethyl Alkylamines, CH2(OH).CH2(NHR) and CH2(OH)CH2(NR2), are best prepared by the addition of ammonia or the corresponding primary and secondary amines to ethylene oxide in aqueous solution (A. 315, 104; 316, 311). Hydroxyethyl Dimethylatnine, CH2(OH).CH2N(CH8)2, is also obtained by the breaking down of methyl morphimethin (Vol. II. : Alkaloids), (B. 27, 1144). Choline, Hydroxyethyl Trimethy I Ammonium Hydroxide, Bilineurine, Sincalin, HOCH2.CH2.N(CH3)3OH, is quite widely distributed in the animal organism, especially in the brain, and in the yolk of egg, in which it is present as lecithin, a compound of choline with glycero- phosphoric acid and fatty acids. It is present in hops, hence it occurs in beer. It has also been found in the plant Strophanthus. It is obtained, also, from sinapin (the alkaloid of Sinapis alba], when it is boiled with alkalis (hence the name sincaliri). It occurs, together with muscarine, (HO)2CHCH2N(CH3)3OH(?) (B. 27, 166), in fly agaric (Argaricus muscarius). History. — A. Strecker discovered this base (1862) in the bile of swine and oxen. He gave it the name choline, from x°^> bile. Liebreich obtained it from protagon, a constituent of the nerve substance, and at first named it nettrine, from vfvpov, nerve ; this he later changed to bilineurine, to distinguish it from the corresponding vinyl base, which continued to bear the name neurine. The constitution of choline was explained by Baeyer, and Wurtz showed how it might be synthetically prepared by the action of trimethylamine on a concentrated aqueous solution of ethylene oxide : CH2V CH2OH | >0+H20+N(CHS)8=| CH/ CH2N(CH3)3OH. Its hydrochloride is produced from ethylene chlorhydrin and trimethylamine. Ethylene bromide and trimethylamine at 110-120° produce bro methyl trimethyl ammonium bromide, which on heating with water at 160°, gives choline hydrobromide, HOCH2CH2N(CH)3Br (B. 36, 2901). Choline deliquesces in the air. It possesses a strong alkaline reaction and absorbs CO2. Its platinum double salt, (C5H14ONC1)2.- PtCl4, crystallizes in beautiful reddish-yellow plates, insoluble in alcohol. See B. 27, R. 738, for choline derivatives. Isocholine, CH3CH(OH)N(CH3)3OH, is obtained from aldehyde-ammonia (B. 16, 207). Homocholine, HOCH2CH2CH2CH2N(CH3)3OH (B. 22, 3331). Neurine, Vinyl Trimethyl Ammonium Hydroxide, CH2:CH.N(CH3)3OH, re- sembles choline, from which it is produced when choline undergoes putrescent decomposition or when boiled with barium hydroxide solution. It has also 330 ORGANIC CHEMISTRY been obtained from the brain substance. It occurs with the ptomaines— alkaloids of decay of proteins, particularly in animal bodies. It may be derived from the bromide corresponding with choline (obtained by treating ethylene bromide with trimethylamine), and the iodide (resulting from the action of HI on choline) when they are subjected to the action of moist silver oxide : CH2.OH aHl CH2I Ag2Q CHa CH2N(CH3)3OH CH2N(CH3)3I Hz° CHN(CH3)3OH. Choline. Neurine. Contrary to choline, which is harmless, neurine is exceedingly poisonous. CO O BetaYne, Trimethyl Glycocoll, Oxyneurine, Lycine, \ \ , is CH2— N(CH8)3 allied to choline and neurine, from which it is obtained by oxidation (Liebreich, B. 2, 13) : CH2OH 2o COOH _H20 CO-O CH2: CH2N(CH3)3OH CH2N(CH3)3OH CH2N(CH3),. Choline. Betaine. As it is a derivative of amino-acetic acid it will be more closely examined, in company with other betai'iies, with the amino-fatty acids. fi-Amino-ethyl Ether C2H5OCH2CH2NH2, b.p. 108°, is obtained from j8-chlor-or j8-brom-ethylamine by means of sodium alcoholate. p-Dimethylamine Ethyl Ether, C2H5OCH2.CH2N(CH3)2, b.p. 121°, occurs in the break-down products of various morphine bases (Vol. II. : Alkaloids) (B. 37, 3504 ; 38, 3150).. Dihydroxyethylamine, NH(CH2CH2OH)2, m.p. 28°, b.p.100 270°, is prepared from ethylene oxide and dibromodiethylamine. ft'Diaminoethyl Ether, O(CH2CH2NH2)2, b.p. 183-184°, is obtained by the break-down of its diphthalyl derivatives, which, in turn, are prepared from diido-ether and 2 molecules of potassium phthalimide (B. 38, 3411). PTT pf-T Diethyleneimide Oxide, Morpholine, O<£H2'£g2>NH, is produced when dihydroxyethylamine is heated to 160° with sulphuric acid, and distilled with potassium hydroxide; also, from diiodo-ether (pp. 129, 320) and toluene sulpho- namide (Vol. II.), and subsequent decomposition of the toluene sulphomorpholine formed (B. 34, 2606). See B. 22, 2081, for homologous morpholines. It is assumed that the same atomic grouping exists in morphine as in morpholine, hence the name. Trihydroxyethylamine, N(CH2CH2OH3), b.p. 278°, i-Amino-2-propanol, CH3CH(OH).CH2(NH2), b.p. 161°; i-Amino-2-butanol, CH3CH2CH(OH)CH2.NHt, b.p. 204°, 2-Amino-i-pentanol, CH3CH2CH(OH)CH(NH2)CH3, b.p. 174°, etc., are prepared by reduction from, the corresponding nitro-alcohols ; i-Amino-2- propanol and 2-Amino-^-butanol, CH3CH(OH)CH(NH2)CH3, also from the corresponding isonitroso-ketones ; i-Amino-2-butanol and 2-Amino-^-pentanol also from the corresponding amino-ketones (B. 32, 1905 ; 33, 3169 ; 37, 2480 ; C. 1902, I. 716, 717). i-Amino-4-butanol, CH2(OH).[CH2]2CH2(NH2), b.p. 206°, is produced from y-cyanopropyl alcohol by sodium and alcohol (B. 33, 3170); methyl ether (B. 32, 948). Diacetone Alkamine, (CH3)2C(NH2).CH2CH(OH)CH3, b.p. 175°, results on reducing diacetonamine (p. 230) (A. 183, 290 ; B. 30, 1318). For homologous alkamines, see also B. 14, 1876, 2406; 15, 1143 ; 28, 3111 ; 29, 1420, etc. (b) Halogen Alkylamines, or Haloid Esters of the Hydroxyalkylamines.— In NITROGEN DERIVATIVES OF THE CLYCOLS 331 the free state these bodies are soluble in water and not very stable. They easily change to salts of the cyclic imines, e.g. chloramylamine, C1CH2(CH2)4NH2, becomes pentamethyleneimide or piperidine hydrochloride, CH2.(CH2)4NH.HC1. On the transformation of tert.-/J- and y-chloralkylamine into piperazonium bromide, see p. 337. Methods of Formation: (i) The addition of a halogen acid to unsaturated amines, like vinyl- or allylamine, p. 166 (B. 21, 1055 ; 24, 2627, 3220 ; 30, 1124). (2) By the action of halogen acids on hydroxyalkylamines. (20) By mixing the nitriles of the halogen substituted acids with sodium phenolate, reducing and heating with a halogen acid (B. 24, 3221 ; 25, 415) : Cl.CH2CH2CH2CN+NaOC,H6=C,H5O.CH2CH2CHaCN+NaCl 4H aHCl CeH5OCH2[CH2]2CN - X:6H6.OCH2[CH2]2CH2NH2 - X2CH8[CHJ8NHa.HCl. (3) From imidochlorides, which result from the action of PC16 on the alkylene dibenzoyl diamines (p. 321), by distillation under reduced pressure (B. 88, (4) When the halogen alkyl phthalimides are heated with halogen acids (B. 21, 2665 ; 22, 2220 ; 23, 90), e.g. : Bromethyl Phthalimides. o-Phthalic Acid. The following are known : Chlor-, brom-, iodo-ethylamine, ICH2CH2NH2; transformation of bromethyl- amine into ethylene imide, see p. 355. f$-Chlor ethyl Dimethylamine, C1CH2CH2N.- (CH3)2, b.p. 110°, is an oil. Its aqueous solution changes on keeping or evapora- tion into tetramethyl piperazonium chloride (p. 336) (B. 37, 3507). fi-Bromo- propylamine, CH3CHBrCH2NH2, results from boiling allyl mustard oil with hydrobromic acid, and is obtained as a hydrobromide (B. 32, 367). y-Chloro- propyl Dimethylamine, C1CH2CH2CH2N(CH3)2, b.p. 135° (B. 39, 1420). y-Bromo- propylamine, BrCH2CH2CH2NH2. fi-Bromobutylamine, CH3CH2CHBrCH2- NH2. y-Chlorobutylamine, CH3CHC1.CH2CH2NH2 (B. 28, 3111). 8-Chloro- butylamine, C1CH2[CH2]2.NH2. c-Chloroamylamine, C1CH2[CH2]4NH2. B- M ethyl- c-chloro-n-amylamine, CH2C1[CH2] 2CH(CH3)CH2NH2. B-n-Propyl-c- chloro-n-amylamine, CH2C1[CH2]2CH(C3H7)CH2NH2 (B. 27, 3509; 28, 1197). The four last compounds lose HC1 and form tetramethylene imine and pentamethylene imine (p. 336) ; or piperidine, pipecoline, and jS-propyl piperidine. 6-Chlorohexylamine, C1[CH2]6NH2, and 'j -Chlor oheptylamine, C1[CH2]7NH2, with 5-chloroamylamine, are obtained from the alkylene dibenzimide chlorides (method above), and, like it, yield a cyclic imide (p. 334). Dibromodiethylamine, NH(CH2CH2Br)2 (B. 30, 809). (c) Sulphur derivatives of Hydroxyethylamine. Aminoethyl Mercaptan Hydro- chloride, HC1.NH2.CH2CH2SH, m.p. 71°. Thiodiethylamine, (NH2CH2CH2)2S, b.p. 232° (comp. Ethylene Imine, p. 335). Diaminoethyl Bisulphide Hydro- chloride, (NH2CH2CH2S).2HC1, m.p. 253°. Diaminodiethyl Sulphone, (NH2CH2- CH2)2SO2, and Diaminosulphonal, (NH2.CH2CH2SO2)2C(CH3)2, m.p. 85°, are prepared from bromethyl phthalimide (B. 22, 1138; 24, 1112, 2132, 3101; 35, 1372). Taurine, Aminoisethionic Acid, NH2CH2CH2SO3H, has already been discussed under isethionic acid (p. 325). II. Alkylene Diamines. — The di-, like the monovalent alkyls, can replace two hydrogen atoms in two ammonia molecules and produce primary, secondary, and tertiary diamines. These are di-acid bases, and are capable of forming salts by direct union with two equivalents of acids. Some of them have been detected with the ptomaines or alkaloids of decay (B. 20, R. 68) and are therefore worthy of note, e.g. tetramethylene diamine, and pentamethylene diamine or cadaver ine. 332 ORGANIC CHEMISTRY Formation : (i) They are prepared by heating the alkylene bromides with alcoholic ammonia to 100° (p. 157) in sealed tubes : BrCH2.CH2Br+2NH3=C2H4<^2.2HBr Ethylene Bromide. Ethylene Diamine. Diethylene Diamine. Iv ^2A1.4 , V,H/ Triethylene Diamine. To liberate the diamines, the mixture of their hydrobromides is distilled with KOH and the product is then fractionated. (2) Another very convenient method for the preparation of diamines is the reduction of (a) alkylene dicyanides or nitriles of dicarboxylic acids (q.v.) with metallic sodium and absolute alcohol (see p. 158 and B. 20, 2215) : CN CH2NH2 CH2.CN CH2.CH2.NHa I +8H=| ; | +8H=| CN CH2NH2 CH2.CN CH2.CH2.NH2. Dicyanogen. Ethylene Ethylene Tetramethylcne Diamine. Cyanide. Diamine. (b) By the reduction of the oximes, (c) of the hydrazones of the dialdehydes and diketones, and (d) of the dinitroparamns. In some of these reductions cyclic imines have been observed ; thus, in the reduction of ethylene cyanide in the presence of tetramethylene diamine, tetra- methylene imine is formed. (3) From dicarboxylic amides, bromine and alkali hydroxide (B. 27, 511) (P- 159). (4) From dicarboxylic azides (J. pr. Ch. [2], 82, 189). (5) From alkylene diphthalimides on heating with HC1: p TJ /(•OCOx.Arrru n •Nr<r'CO(i)%ir TJ . ^ 2CgH4(CO2H)j, • 4Wo \PO^ L^-LA2J3-1-N ^PO^--^ I 6 4 TT .. r PTP1 "MW PW PW PM "NTTT TTP1 ^2)v>vJ L-L/^2jj * 4.H2O rlV^l.JNJrl jUli2UrljjL/ii2-W Jrl2.ilL/l Trimethylene Diphthalimide. Trimethylene Diamine Hydrochloride. (6) From diamino- mono- and -di- carboxylic acid, by dry distillation (C. 1905, 11.463): CH2.CH2.CH(NH2)COOH CH2CH2CH2NH8 | +2COr ;H2.CH2.CH(NH2)COOH CH2CH2CH2NH2 Properties. — The alkylene diamines are liquids or low melting solids of peculiar odour, which, in the case of those that are volatile, resembles that of ammonia, and recalls that of piperidine. They fume slightly in the air, and absorb carbon dioxide. It is found that the melting points of the homologous series are not regular in their increase, but those of members containing an even number of C atoms are higher than of those containing an uneven number. The boiling points, on the other hand, show a regular increase (J. pr. Ch. [2] 62, 192 ; C. 1901, I. 610). Reactions. — Alcohol and acid radicals can be introduced into the amino- groups of the diamines in the same manner as in the amino-groups of the mon- amines (Action of formaldehyde, see B. 36, 35). The production of the dibenzoyl derivatives, e.g. C2H4(NHCOC6H5)2, upon shaking with benzoyl chloride and sodium hydroxide, and the formation of phenyl ureas, (CH2)OT(NHCOC€H6)2, by the action of phenyl cyanate, is well adapted for the detection of the diamines (B. 21, 2744 ; C. 1905, I. 274). On the conversion of the alkylene dibenzoyl diamines into chloralkylamines and alkylene dichlorides, see p. 320. Nitrous acid converts them into glycols, at the same time unsaturated alcohols and unsaturated hydrocarbons arise (B. 27, R. 197). Further, the diamines unite directly with water, forming very stable ammonium NITROGEN DERIVATIVES OF THE GLYCOLS 333 oxides, which only give up water again when they are distilled over potassium hydroxide (comp. Pentamethylene Diamine) : CH,NH2 CH2NH3 v +H20=| CH2NH2 +H2O= I >O, Ethylene Diamine Hydroxide. CH2.NH/ By loss of ammonia they pass into cyclic imines. Ethylene Diamine, C2H4<^2, m.p. 8-5°, b.p. 116-5°, combines with water to form Ethylene Diamine Hydroxide, m.p. 10°, and b.p. 118°. It reacts strongly alkaline, and has an ammoniacal odour. Nitrous acid converts it into ethylene oxide. Ethylene Dinitramine, NO2NHCH2.CH2NHNO2 (B. 22, R. 295). Thionyl Ethylene Diamine, SO : N.CH2.- CH2.N : SO, m.p. 5°, b.p.26 100° (B. 30, 1009). Ethylene diamine and a/J-propylene diamine, like the orthodiamines of the benzene series, combine with orthodiketones, e.g. phenanthraquinone and benzil, to form pyrazine derivatives, similar in structure to the quinoxalines. They also unite with the benzaldehydes and benzoketones (B. 20, 276 ; 21, 2358). The action on ethylene diamine of CSC12 (B. 27, 1663), and of aldehydes (C. 1899, I. 594; B. 40, 881). Diacetyl Ethylene Diamine, m.p. 172°, consists of colourless needles. When this compound is heated beyond its melting point, water splits off, and there follows an inner condensation that leads to the formation of a cyclic amidine base, closely allied to the glyoxalines. It is ethylene ethenyl amidine or methyl glyoxalidine, which under the name Lysidine, m.p. 105°, b.p. 223°, has been recommended as a solvent for uric acid (B. 28, 1176). The corresponding propylene and trimethylene diamine derivatives react similarly (B. 36, 338) : CH2NHCOCH3 CH2.NH\ \CCH3+CH3CO,H. CH2NHCOCH3 C Diacetyl Diethylene Ethylene Etheny Diamine. Amidine. CH3.CH.NH2 Propylene Diamine, | , b.p. 119-120° (B. 21, 2359), has been CH2.NH2 resolved into optically active components by means of d-tartaric acid. 1-Propylene Diamine, [a]D=— 19-1 1°, forms a d-tartrate, which is sparingly soluble (B. 28, 1180). Trimethylene Diamine, CH2<*.NH2 bp I35_I36<> (B 2670), has been prepared by general methods i, 3, and 4 (from glutaric diazide), and (2d) by reduction of 1,3-dinitropropane (p. 155). ay-Trimethyl Trimethylene Diamine pd-Diamino-p-methylpentane, (CH3)2C- (NH2)CH2CH(NH2)CH3, is obtained from diacetone amino-oxime (p. 230) by reduction with sodium amalgam (M. 23, 9) ; also by reduction of acetyl acetone dioxime with sodium and alcohol. By the second method a labile a-diamino- pentane, b.p.20 47°, is produced which is converted into the stable /8-diamino- pentane, b.p.j2 44°, by prolonged boiling with alkalis. Both bases yield cyclic ethenyl amidines when heated with acetic acid (see above) (B. 32, 1191). Tetramethylene Diamine, i,^-Diaminobutane, NH2[CH2]4NH2, m.p. 27°, is obtained from ethylene cyanide by general methods 2a and 26 from succin- aldehyde dioxime (p. 355) (B. 22, 1970 ; 40, 3872). It is found during cystinuria in the urine and faeces. With regard to its identity with putresceine (which is produced during putrescence), see B. 40, 3875. Tetramethyl Tetra- methylene Diamine, (CH3)2N.[CH2]4.N(CH3)2, b.p. 169°, occurs in Hyocyamus, Henbane (B. 40, 3869). i,4-Diaminopentane, CH8CH(NH2)CH2CH2CH2NH2, b.p. 172°, is formed from the nitrile of pyroracemic acid according to method of formation za. 2,5-Diaminohexane, CH3CH(NH2)CH2.CH2CH(NH2)CH3, b.p. 175°, is formed from the diphenylhydrazone of acetonyl acetone (p. 356) according to method of formation 2c. It exists in two forms which are characterized by their dibenzoyl derivatives : o-derivative, m.p. 238° ; /J-derivative, m.p. 183-185°. 334 ORGANIC CHEMISTRY They bear a relation to each other similar to that shown by racemic acid and mesotartaric acid (B. 28, 379). i,4-Diamino-2-methyl P£wtaw0,CH3CH(NH2)CH2.CH(CH3)CH2NHa, b.p. 175°, is obtained from a-methyl laevulindialdoxime (p. 355) according to method of formation zb (B. 23, 1790). Penlamethylene Diamine, Cadaverine, i.s-Diaminopentane, NH2CH2.CHa.- CH2.CH2CH2NH2, b.p. 178-179°, is obtained by the reduction of trimethylene cyanide (method of formation 2.0) (B. 18, 2956 ; 19, 780) ; also from penta- methylene diphthalimide (by method of formation 5) (Preparation, see B. 37, 3583) ; and further, from lysine (i,5-diaminocaproic acid) (mode of formation 6, p. 332). It forms a hydrate containing 2H2O (B. 27, R. 580). It is identical with cadaverine, a ptomaine isolated from decaying corpses (B. 20, 2216, and R. 69). Neuridine, C6H14N2 (B. 18, 86), formed by the decay of fish and meat, is isomeric with pentamethylene diamine. Hexamethylene Diamine, i,6-Diaminohexane, NH2[CH2]6NH2, m.p. 42°, b.p. 20 i°o°» is formed in the hydrolysis of Hexamethylene Diethyl Urethane, [CH2]8(NHCOaC2H6)2, m.p. 84°, which results upon boiling the suberic acid azide with alcohol (J. pr. Ch. [2] 62, 206). Also from i,6-diaminosuberic acid ' by distillation (mode of formation 6, p. 332) ; further, by reduction and hydrolysis of e-benzoylaminocaproic acid nitrile, C6H5CONH[CH2]5CN (B. 38, 2204). Heptamethylene Diamine, NH2(CH2]7NH2, m.p. 29°, b.p. 224°, is prepared from azelaic amide and KBrO, and from pimelic nitrile by reduction (B. 38, 2204). i,8-Diamino-octane, CH2NH2[CH2]6CH2NH2, m.p. 51°, b.p. 226°, is obtained from the amide or azide of sebacic acid (method of formation 3 or 4) (J. pr. Ch. [2] 62, 227); and from i,8-diaminosebacic acid (method of formation 6, p. 332). Its hydrochloride gives a-butyl pyrrolidine on heating (C. 1906, II. 527). i,g-Diamino-nonane, m.p. 37°, b.p. 258°, is obtained from azelaic nitrile (q.v.) (C. 1897, H. 849). i,io-Dekamethylene Diamine, NH2CH2(CH2)8CH2.NH2, m.p. 61-5°, b.p.lt 140°, results from the nitrile of sebacic acid (method of formation 2.0] (B. 25, 2253). Cyclic Alkylene Imines. Two classes of these substances are known — the alkylene monimines, which contain one imino-group, and the dialkylene diimines, which contain two alkylene residues and two imino-groups. I. Alkylene Monimines. To this group belong compounds corresponding with the alkylene oxides : >— /^j.j.a\ CH2 — CH2>. /CH2 — CHa\ NH CH/ >NH | >NH CH/ >NH. v,x,2 XCH/ CH2— CH/ \CH2— CH/ Dimethylene Imine Trimethylene Tetramethylene Pentamethylene Ethylene Imine. Imine. Imine. Imine. Methods of Formation. — (i) Upon heating the diamine hydrochlorides, when ammonia splits  Diamine Hydrochloride. Pentamethylene Imide, Piperidine. (2) By the splitting-off of halogen acid from the halogen alkyl amines — e.g. when the hydrochloride is heated, or when it is digested with dilute potassium hydroxide (B. 24, 3231 ; 25, 415) : ClCHaCH2CH2CH2CH2NH2 = CH2CH2CHaCH2CH2NH.HCl. «-Chloramylamine. Piperidine Hydrochloride. (3) They are produced, together with the diamines, in the reduction of alkylene dicyanides. NITROGEN DERIVATIVES OF THE GLYCOLS 335 The tendency to form imino-rings and the stability of such rings towards reagents producing cleavage, depends on the number of members taking part in their structure, as has been seen to be the case among the ethylene oxides (P- 317)- Whilst ethylene imine is easily decomposed (see below), the tetra- and penta- methylene imines are very stable, and special methods are required to break them open. Such are : (i ) the iodomethylate method, which breaks the quaternary ammonium iodides into olefine dialkyl amines by means of alkali ; (2) oxidation of the benzoyl imines , which produces benzoyl amino-fatty acids ; (3) heating benzoyl amines with phosphoric halides, forming dihalogen paraffins and benzo- nitrile (comp. p. 321). These methods will be discussed under Heterocyclic Compounds (Vol. II.). The investigation of the hexa-, hepta, and deca-methylene imines leaves it rather doubtful as to whether these ring-systems can exist ; it appears, however, that the hydrochloride of octomethylene diamine can be prepared by heating decamethylene diamine, with the partial atomic rearrangement to form a-alkyl pyrrolidine (see below) (comp. B. 39, 2193, 4110 ; C. 1906, II. 527). CH2v Ethylene Imine, Dimethylene Imine, \ yNH, b.p. 55°, D20 =0-8321, is CH2 obtained from bromethylamine by means of Ag2O or potassium hydroxide solu- tion. It is a water-clear liquid, which smells strongly of ammonia, dissolves in water, and acts corrosively on the skin. It is stable against permanganate and bromine, which shows that the above formula is correct rather than the earlier vinyl formula which was assigned to it. With benzene sulphochloride (Vol. II.) and alkali, it forms a sulphamide, insoluble in alkali. It combines with hydro- bromic acid in the cold to form bromethylamine, with H2S to thiodiethylamine, CH2X and with sulphurous acid to taurine. n-M ethyl Ethylene Imine, \ >NCH3, 2X ne, \ J> CH2 b.p. 28°, is prepared from chlorethyl methylamine, C1CH2CH2NHCH3, and alkali. Similarly to ethylene imine, it is converted by iodomethane into iodo-ethyl trimethyl ammonium iodide, ICH2CH2N(CH3)2I (B. 34, 3544). Trimethylene Imine, CH3<^2>NH, b.p. 63°, D20 =0-8436. If trimethylene bromide and alkali react on ^-toluol sulphamide, p-toluol sulphotrimethylene imide is produced ; and when this is hydrolyzed by sodium in amyl alcohol solution, trimethylene imide is produced. It is easily decomposed by acids, as is ethylene imine (B. 32, 2031). C"H2'C/H2\ Tetramethylene Imine, Tetrahydropyrrole, Pyrrolidine, \ /NH, b.p. 87°, CH2.CH/ is obtained from tetramethylene diamine (method of formation i) ; from 8-chlorbutylamine and potassium hydroxide (method 2) (B. 24, 3231), and by the reduction of pyrroline, the first reaction-product of pyrrole (B. 18, 2079), and of succinimide (see Succinic Acid) (B. 32, 951) : CH=CHV 2H CH.CH2X 2H CH2.CH2V | >NH -- > || >NH - > | >NH. CH=CHX CH-CH/ CH2.CH/ Pyrrole. Pyrroline. Pyrrolidine, Tetramethylene Imide. Tetramethylene imide has an odour resembling that of piperidine. Tetra- methylene Nitrosamine, C4H8NNO, b.p. 214° (B. 21, 290). n-Methyl Pyrrolidine, (CH2)4NCH3, b.p. 82°, is produced by distillation of tetramethyl tetramethylene diamine dichloromethylate (p. 333). CH2.CH(CH3 1- or a-M ethyl Pyrrolidine, \ ^^>NH, b.p. 79°, is obtained from " y-valerolactam (q.v.), 2- or ft- Methyl Pyrrolidine, b.p. 103° (B. 20, 1654). i, ^-Dimethyl Pyrrolidine, b.p. 107° (B. 22, 1859). 1,^-Tetramethyl Pyrrolidine (C. 1905, II. 830). 336 ORGANIC CHEMISTRY Pentamethylene Imine, Piper idine, Hexahydropyndine, b.p. 106°, is obtained according to methods I, 2 (B. 25, 415) and 3 (p. 334) ; also from pipeline (Vol. II.), and by the reduction of pyridine, into which it passes when it is oxidized : 6H .y^-.— V—-.V f y^/ilj.V-'.rij'V CH^ >N 3° CH2< >NH. XCH=CH/ < N:H2.CH/ Pyridine. Piperidine. Piperidine bears the same relation to pyridine that is sustained by pyrrohdine to pyrrole. Therefore, tetramethylene imide and penta- methylene imide link the pyrrole and pyridine groups to the simple aliphatic substances, the diamines, and their parent bodies, the glycols. The pyrrole and pyridine derivatives will be discussed later in connection with the heterocyclic ring systems, together with alh'ed bodies, and pyrrolidine and piperidine will again be referred to. II. Dialkylene Diimines. This class embraces those compounds corresponding with diethylene oxide . 316), diethylene disulphide (p. 324), and diethylene imido-oxide or morpholine Diethylene Diimine, Piperazine, Hexahydropyrazine, . CH m.p. 104°, b.p. 145°, was first prepared by the action of ammonia on ethylene chloride. It is produced by heating ethylenediamine hydrochloride (B. 21, 758), and by the reduction of pyrazine, N<^CH^CH^N (B- 26' ?24)' li is tecnnicallY made from diphenyl diethylene diamine, the reaction-product of aniline and ethylene bromide, when it is converted into the p-dinitroso-compound, and the latter then broken down into p-dinitrosophenol and diethylene diamine : Diethylene diamine, or piperazine, is a strong base, soluble in water, which upon distillation with zinc dust, changes to pyrazine (Vol. II.) (B. 26, R. 441). It is important that piperazine unites with uric acid to form a salt even more readily soluble than the lithium salt. Hence its strongly alkaline, dilute solution has been recommended as a solvent for uric acid (B. 24, 241). For piperazine derivatives, see B. 30, 1584. Quaternary Piperazonium Halides are obtained by the action of iodo-alkyls on piperazine (B. 36, 145) ; and also by spontaneous change of /?-chlor- or brom- ethyl dialkylamines (p. 331) whereby the oily bases are converted into solid neutral salts : 2ClCHaCH2N(CH,), -- > C1N(CH,)2<™^^>N(CH,)SC1. Chlorethyl Dimethylamine. Tetramethyl Piperazonium Bichloride. Alkali produces ethylene methylimine and the polymeric n-dimethyl piperazine, whilst chlor- and brom-ethylamine yield only ethyleneimine. ALDEHYDE-ALCOHOLS 337 Dipiperidyl Piperazonium Bromide, obtained, analogously to the above, from j8-bromethyl piperidine, (CH2)6NCH2- CHaBr. It is also prepared from piperazine and two molecules of dibromo- pentane. These quaternary piperazonium halides are decomposed by alkalis partly into acetylene and tetra-alkyl ethylene diamines : and partly into hydroxethyl dialkylamines. Dry distillation decomposes tetramethyl piperazonium chloride into chloro- methane and n-dimethyl piperazine (B. 37, 3507 ; 38, 3136 ; 40, 2936). Trimethylene Ethylene Diimine, NH<™2~™222^f7?NH, b.p. 169°, is prepared from trimethylene ethylene p-toluene sulphimide, and HC1 (B. 32, 2041 ; 33, 761). Bis-Trimethylene Diimine, NH<™2£^2™a>NH, m.p. 15°, b.p. 187-, is obtained from its p-toluene sulphimide, which is the product of reaction between trimethylene bromide and the di-sodium salt of di-p- toluene sulpho- trimethylene diamide, CH3C.H4SO2NNa.CH2CH2CH2.NNaSO2C6H4CH, (B. 32, 2038). The spontaneous change of y-chloropropyl dimethylamine, C1CH2CH2CH2N» (CH,)2, produces Bis-trimethylene Tetramethyl Diimonium Chloride, C1(CH3)2N- [CH2CH2CH2]2N(CH3)2C1 (comp. above, piperazonium bromide; and B. 39, 1420). 2. ALDEHYDE-ALCOHOLS These contain both an alcoholic hydroxyl group and the aldehyde group CHO, hence their properties are both those of alcohols and aldehydes (p. 191). The addition of 2 H-atoms changes them to glycols, whilst by oxidation they yield the hydroxy acids, containing a like number of carbon atoms. The most important representatives of this group are the j3-hydroxyaldehydes or aldols, which result from the aldol condensation of the simple aldehydes. Glyeollic Aldehyde, [Ethanolal], CH2(OH)CHO, m.p. 95-98°, is the first aldehyde of glycol, and can be obtained from it by oxidation with hydrogen peroxide in the presence of ferrous salts. It is also prepared from bromacetalde- hyde and barium hydroxide solution, and from chloracetal by treatment with alkali followed by acid (C. 1903, I. 1427). Further, it is very easily produced from dihydroxymaleic acid (an oxidation product of tartaric acid) by heating it with water at 50-60°. A noteworthy formation, although only in small quantities, is that by condensation of formaldehyde by means of CaCOs (B. 39, 50). Glyeollic aldehyde remains behind, when its solution evaporates, as a slightly sweet syrup ; this can be distilled under reduced pressure, when it solidifies ; on melting it undergoes condensation very easily. Bromine water oxidizes it to glycollic acid (p. 362), whilst it is condensed by sodium hydroxide solution to tetrose (q.v.), and by sodium carbonate solution to acrose (q.v.) (B. 25, 2552, 2984 ; C. 1899, II. 88 ; 1900, I. 285). Hydroxylamine gives rise to an oily oxime (C. 1900, II. 312), and phenylhydrazine and acetic acid produce glyoxal osazone (p. 356). The following derivatives of glycol aldehyde have already been discussed : CHO CH(OC2H6)2 CHC1, CHC1. II II CH2Cl(Br,I), CHaCl(Br) CH2OH CH2C1 Monochlor- (brom-, iodo-) Monochlor-(brom- Dichlorethyl i,2-Trichlorethane acetaldehyde (p. 203). acetal (p. 205). Alcohol (p. 117). (p. 95). Glycol Acetal, CH,OH.CH(O.C2H6)2, b.p. 167°, is obtained from bromacetal (B. 5, 10). VOL. I. Z 338 ORGANIC CHEMISTRY Glycol Dimethyl Acetal, CH2OH.CH(OCH3)2, b.p. 158°, is produced from glycol aldehyde by hydrochloric acid in methyl alcoholic solution (B. 39, 3053). Ethoxyacetal, C2H5O.CH2CH(OC2H5)2J b.p. 168°, is prepared from i,2-dichlor- ether (p. 129), or from chlor- or brom-acetal and sodium alcoholate. Greatly diluted sulphuric acid or a molecular proportion of water in acetone solution produces Ethoxyacetaldehyde, CaH6O.CH2CHO, b.p. 71-73° (B. 39, 2644 ; C. 1905, I. 1219 ; 1907, I. 706). Phenoxy acetal, C6H6O.CHa.CH(OC2H6)2, b.p. 257° (B. 28, R. 295)- a-Hydroxypropionaldehyde, CH8CH(OH)CHO, is unknown. a-Acetoxypro- pionaldehyde, b.p.i5 52-55°, is formed when a-iodopropionaldehyde and silver acetate react. Heated with water to 100°, acetol (Hydroxyacetone, p. i) is formed. It is also obtained when o-bromopropionaldehyde is heated with potassium formate and methyl alcohol, instead of the expected a-hydroxypro- pionaldehyde (A. 335, 266). Dichlorisopropyl Alcohol, C12CHCH(OH)CH3, b.p. 147°, can be looked on as. a derivative of a-hydroxypropionaldehyde. It is prepared from dichloraldehyde and CH3MgBr (B. 40, 27). a-Hydroxybutyl Aldehyde, (CH8)2C(OH).CHO, b.p. 137°, is prepared from a-Bromoisobutyl Aldehyde, b.p. 113°, and water. It is an easily polymerizable liquid. Sodium hydroxide solution converts it into isobutylene glycol (p. 313) and a-hydroxybutyric acid, a reaction which other aldehydes undergo (M. 21, 1122). fi-Hydroxypropionaldehyde, Hydracrylic Aldehyde, HOCH2.CH2CHO, b.p.18 90°, is produced when acrolein is heated with water to 100° : semicarbazone, m.p. 114°, regenerates acrolein when treated with bisulphate. It easily poly- merizes. Alkali partially converts it to crotonaldehyde (A. 335, 219). J3- Hydroxypropionacetal, OHCH2.CH2.CH(OC2H6)2, b.p.to 98°, is prepared by prolonged boiling of dilute sodium hydroxide solution at 115° with fi-Chloro- propionacetal, b.p.20 74°, the addition product of acrolein acetal (p. 213) and HC1 (B. 33, 2760). Isotriethylin, CH3CH(OC2H6)CH(OC2H5)2, or possibly CH2(OC2H6).CH(OC2H5)2, b.p.18 81°, results when acrolein and alcohol are heated together at 50° for several days ; and also by the action of orthoformic ether on acrolein (B. 31, 1014). Aldol, p-Hydroxybutyraldehyde, CH3.CH(OH).CH2.CHO, b.p.12 60-70°, D0=i*i20, was discovered by Wurtz in 1872. It is obtained by the condensation of acetaldehyde by means of dilute cold hydro- chloric acid, and other condensation agents, e.g. K2CO3 (B. 14, 2069 ; 24, R. 89 ; 25, R. 732 ; M. 22, 59 ; C. 1907, 1. 1400). Aldol freshly prepared is a colourless, odourless liquid, and is miscible with water. It distils under atmospheric pressure, partially reforming acetaldehyde, but it mainly becomes converted into croton- aldehyde and water. As an aldehyde it will reduce an ammoniacal silver nitrate solution. Heated with silver oxide and water it yields j8-hydroxybutyric acid, CH3.CH(OH).CH2.C02H. After prolonged standing aldol polymerizes, becoming viscous, sometimes depositing crystals of Paraldol, (C4H8O2)2, m.p. 80-90° (M. 21, 80). If, during the preparation of aldol, the mixture of aldehyde and hydrochloric acid be left undisturbed, the aldol condenses with loss of water to Dialdan, C8H14O3, m.p. *39°» a crystalline body which reduces ammoniacal silver solution. Tetraldan, C18H2,Og, is formed simultaneous with dialdan, and does not reduce silver from its ammoniacal solution (C. 1900, II. 838). Diethyl Acetal of fi-Ethoxybutyric Aldehyde, CH3.CH(OC2H6)CH2.CH(OC2H6)2, b.p.14 73° (B. 31, 1014). The aldol condensation is characteristic for this class of substance and occurs among the higher members of the series when a free hydrogen atom exists next to the aldehyde group. Thus, a series of jS-hydroxyaldehydes or aldols can be prepared. A mixture of two aldehydes yields mixed aldols. The condensing agent mostly employed is potassium carbonate : 2CH3.CH2CHO = CH3CH2CH(OH)CH(CH8)CHO CH.O + fCHj^CHCHO = CH,(OH)C(CH,),CHO,. NITROGEN-CONTAINING DERIVATIVES 339 Like aldol itself, the homologous aldols are easily converted into a./J-olefine aldehydes when a hydrogen atom in the a-position is free, and are stable bodies. 