agent, and after long-continued action at ordinary temperatures the completion of the process assisted by heat. The solution is finally evaporated on a water bath, in order to expel all nitric acid, the residuary strongly acid liquid diluted with water and saturated with plumbic carbonate. From the filtered solution the crystalline lead salt (CnH2n+1.SO2.0),Pb can be obtained by evaporation, and is then decomposed in aqueous solution by sulphuretted hydrogen. The liquid, freed from plumbic sulphide by filtration, gives by evapo ration on a water bath the free sulphonic acid as a strongly acid syrup, which crystallises, under a desiccator, after a while. By neutralisation by metallic carbonates the metallic salts, which are mostly readily soluble, can be obtained. Another method of preparation consists in heating alkylic haloids with normal potassic sulphite: The alkylsulphonic acids are very stable compounds. They can be heated to pretty high temperatures without decomposition, are not altered by boiling with potassic hydrate, being only decomposed by fusion therewith, and are only oxidised with great difficulty by fuming nitric acid. With phosphoric pentachloride they yield in addition to phosphoric oxychloride and hydrochloric acid the insoluble alkylic sulphonic chlorides : 254. Methyl sulphonic acid, CH3.SO2.OH, can be prepared, by the general methods given above, from methylic mercaptan, methylic disulphide, methylic sulphocyanate, and methylic haloids, and in addition from carbonic disulphide. If this latter be heated with damp chlorine or with manganic dioxide and hydrochloric acid, it slowly forms colourless crystals, melting at 135° and boiling at 170°, of trichlormethyl sulphonic chloride: From its aqueous solution, by careful addition of sulphuric acid, the barium can be precipitated and trichlormethyl sulphonic acid obtained: On evaporation of the filtered solution trichlormethyl sulphonic acid crystallises in colourless, deliquescent, strongly acid prisms. The aqueous solution, acidulated with hydrochloric acid, is submitted to the action of a strong galvanic current, the electrodes being plates of amalgamated zinc; by this means the chlorine is completely replaced by hydrogen and methyl sulphonic acid is obtained : CC13 + 3HCI + 3Zn = 3ZnCl2 + CH3 SO2.OH Methyl sulphonic acid is a strongly acid syrupy liquid, which on heating commences to decompose at slightly above 130°, and is only oxidised by fuming nitric acid with great difficulty. Methyl sulphonic chloride, CH3.SO2C1, boils at 150°-153°, and is slowly decomposed by water into hydrochloric and methyl sulphonic acids. very deliquescent crystals; its salts are all easily soluble, and can be submitted to high temperatures without decomposition. Ethyl sulphonic chloride, C2H5.SO,Cl, boils at 171°. Butyl sulphonic acid, CH3.CH2.CH2.CH2.SO2.OH, yields a baric salt, (CH,.SO,O), Ba, H2O, which crystallises in efflorescent tables. Oxidation Products of the Dialkylic Sulphides. 255. Whilst dimethylic sulphide, when heated with nitric acid, is in most part converted into methyl sulphonic acid, with oxidation of one methyl group, diethylic sulphide combines with the oxygen of oxidising agents, and yields peculiar oxides. By evaporating it with dilute nitric acid a thick neutral liquid, which cannot be distilled unchanged, remains, diethyl sulphurous oxide or diethyl thionyl: 2HO.NO2 + H2O + зC2H5>S = x + 1H2O + N202 C2H5 Strong nitric acid converts diethylic sulphide or the preceding body into diethyl sulphone, (C2H5)2SO2: CH3.CH2 It crystallises in large colourless tables, which melt at 70° and distil unchanged at 248°; the substance can, however, be slowly sublimed below 100°. Nascent hydrogen, evolved from zinc and sulphuric acid, reduces diethyl sulphone to diethylic sulphide : (C2H5)2SO2 + 4H = 2H2O + (C2H3)2S. Dimethylic sulphide can be converted into dimethyl thionyl by heating its bromine compound with moist argentic oxide: (CH3)2SBr2+ Ag20 = 2AgBr + (C2H5)2SO. SELENIUM AND TELLURIUM COMPOUNDS OF THE ALCOHOL RADICALS. 256. The compounds of the alcohol radicals with selenium and tellurium are completely analogous to those already described with sulphur. Ethylic seleno-mercaptan, C2H.SeH, is obtained, together with diethylic selenide, (CH),Se, by distillation of potassic seleno-hydrate with potassic ethylic sulphate. The first boils below 100°, and possesses a most unpleasant smell; it readily exchanges its non-radical hydrogen for mercury. Diethylic selenide is a heavy oil, boiling at 107°-108°, which unites with halogens; e.g. (C2H5)2SC12. Ethylic perselenide, C2H-Se, has also been prepared; it boils at 186°. C2H5-Se Diethylic selenide is converted by treatment with nitric acid into diethyl selenious oxide, (C2H5)2SeO, which yields, with excess of nitric acid, a salt of the formula (C2H5),Se(ONO2)2, or Dimethylic selenide is converted by oxidation with nitric acid into methyl selenic acid, CH3.SeO2.OH, which forms prisms, melting at 120°. By mixing dialkylic selenides with alkylic iodides trialkylic selenious iodides, (CnH2n+1)3Sel, are formed, in all respects similar to the trialkylic sulphine iodides. 257. The tellurium compounds possess some further interest; derivatives corresponding to mercaptan have not yet been obtained. Dimethylic telluride, (CH3)2Te, is a liquid boiling at 80°-82°; on exposure to air it is oxidised to dimethyl tellurous oxide, (CH3)2TeO. By heating dimethylic telluride with nitric acid it yields dimethyl tellurous nitrate, (CH3)2Te(O.NO2)2, from whose solution hydrochloric acid precipitates dimethyl tellurous dichloride, (CH3)2TeCl2, as a crystalline body. By treatment with argentic oxide it is converted into dimethyl tellurous oxide. This latter is crystalline, deliquescent, and strongly alkaline; it absorbs carbonic anhydride from the air, and decomposes ammonic salts with evolution of ammonia. With methylic iodide dimethylic telluride yields trimethyl tellurous iodide, (CH3)3Tel, which when treated with freshly precipitated argentic oxide is converted into the highly alkaline and very soluble trimethyl tellurous hydrate, (CH3)3Te.OH. N NITROGEN COMPOUNDS OF THE ALCOHOL RADICALS. 258. The most numerous class of nitrogen compounds of the alcohols correspond to ammonia and its derivations in structure and in properties; in addition the group of compounds of NO, with the alcohol radicals, the nitro-ethanes have been lately added. Alkylamines. 259. The simplest nitrogen compounds of the first group are the alkylamines, i.e. ammonia in which one, two, or all three hydrogen atoms have been replaced by the same number of alcohol radicals. They may be classified into : As the alcohol radicals replacing the hydrogen in the secondary and tertiary amines may be either alike or different, the number of bodies of this kind that can be prepared is very great. 260. Formation from Alcoholic Haloids and Ammonia.-On bringing ammonia together with alkylic haloid, best in alcoholic solution and at a high temperature, direct union occurs. Similarly to the formation of ammonic chloride from hydrochloric acid and ammonia, there is formed by this reaction-but not with the same ease and energy-mon-alkylammonium haloid : or H H CnH2n+1 I NH+CnH2n+1I = NH NH3 + CnH2n+1Cl = N(CnH2n+1)H3Cl. Every ammonic salt, as is well known, is decomposed by alkalies into alkaline salt, water, and ammonia, the hydroxyl group of the metallic hydrate oxidising and removing one of the four hydrogen atoms from the nitrogen compound. Alkalies act in entirely similar manner on the hydrogen of the salts of the amines. If, therefore, the salt obtained in the above reaction be boiled with potassic hydrate, there are formed potassic chloride, water, and a primary amine, which is volatile at the temperature employed: If the primary amine so obtained be again mixed with an alkylic haloid, a secondary ammonic haloid is obtained: which on warming with an alkaline hydrate yields a secondary amine : H H NC2H2n+1 + KOH = KI + HOH + NC2H 2n+1 Cn CnH2n+1 CnH2n+1 The secondary amines further unite with alcoholic iodides, yielding trialkylammonic compounds : H CnH2n+1 H NC2H2n+1 + CnH2n+1I = N CH2+| -CnH2n+1 CnH2n+1 CnH2n+1 I which with alkalies similarly yield potassic iodide, water, and tertiary amines : H CnH2n+1 CnH2n+1 CnH2n+1 NCnH2n+1 + KOH = KI + HOH + N←C2H2n+1 CnH2n+1 These processes are, however, not so simple as above represented; even in the first reaction between ammonia and the alkylic haloid complications occur which render the obtaining of pure products extremely difficult. So soon as some primary ammonic salt has been formed, a portion of it reacts with the other substances present, so as to lead to a real substituting reaction, with formation of some dialkylammonic salt: N(CnH2n+1)HCl + CnH2n+1.Cl + NH, NH,Cl and this latter is then, though only partly, converted into a tertiary ammonic chloride by a similar reaction; |