Methyl guanidine had been known for a long time, under the name of methyl uramine, as a product of the action of mercuric oxide upon creatine and creatinine. It forms a colourless, crystalline, deliquescent mass of strongly alkaline reaction and caustic ammoniacal taste. It decomposes ammonic salts, precipitates metallic oxide from their salts, dissolves aluminic and ferric hydrates, and absorbs carbonic anhydride from the air. Its crystalline salts contain one equivalent of acid and react slightly alkaline. The hydrochloride yields with platinic chloride a double salt, crystallising in the monoclinic system and of the formula: N(CH3)H C-NH,HCI 2PtC16 NH2 On boiling with solution of baric hydrate it decomposes into carbonate, ammonia, and methylamine: N.CH3.H C-NH + Ba(OH)2 + H2O BaCO3 + 2NH3 + N.CH3.H2 NH2 = Disubstituted derivatives have not yet been prepared, but tri derivatives are known. N.C2H.H —N.C2H Triethyl guanidine, C-N.C2H5, is obtained from triethylic N.C2H5.H isocyanurate (§ 281) by heating with an alcoholic solution of sodic ethylate, and separates, in union with water, as a hydrate forming a strongly alkaline oil: It is also obtained by boiling an alcoholic solution of diethyl sulphurea containing much ethylamine with mercuric oxide: N.C2H,.H N.C2H.H N.C2H5.H N.C2H.H +HgO+N.C2H,.H, HgS+ C=N.C2H.H.OH = 2 It absorbs carbonic anhydride from the air, and yields salts with acids. The platino-chloride 2[CSN,(C2H5)3H2.HCl]2,PtCl crystallises in beautiful tables. On distilling hydrated triethyl guanidine, it decomposes into ethylamine and diethyl urea : 289. These compounds, isomeric with the alkylic nitrites (§ 213), are readily obtained by the action of alkylic iodides upon argentic nitrite, which, therefore, probably in great part, is not the salt Ag-O-NO, but Ag-NO2. The reaction goes on with great violence according to the equation: CnH2n+11+ AgNO2 = AgI + CnH2n+1.NO2. The nitro-paraffin is distilled from the argentic iodide and purified by fractionation. The nitro-paraffins are distinguished from the isomeric alcoholic nitrites by their much higher boiling points and greater stability. They do not explode on heating. A property peculiar to those poorer in carbon (it ceases with the butyl compounds) is their power of exchanging one atom of hydrogen for sodium, this occurring either by action of the metal on ethereal solution of the nitro-paraffin or by treatment with sodic hydrate in water or alcohol: 2CnH2n+1-NO2 + Na2 = H2+ 2CnH2nNa.NO2. 2 CnH2n+1.NO2 + NaOH = OH2 + CnH2nHa.NO2. This first reaction by employment of potassium becomes so energetic that the mixture inflames. In these compounds the alkali metal invariably attaches itself to that carbon atom to which the NO2 group is united : On heating the dry metallic compounds they explode violently. In water they are readily soluble, but then easily decompose; in alcohol the sodium compounds are insoluble, the potassium compounds soluble and readily changed. If the fresh aqueous solution of a sodium compound be acidulated, the nitro-paraffin separates unchanged as an oil; if mixed with salts of heavy metals, the latter replace the sodium. These resulting metallic nitro-paraffins are mostly insoluble precipitates. The silver compounds, for instance : CnH2Na(NO2) + AgO.NO2 = NaO.NO2 + C2H1⁄2nAg(NO)2, 2n are curdy precipitates, which rapidly blacken, owing to separation of silver. When the fresh aqueous solutions of sodium or potassium nitroparaffins (obtained by solution of nitro-paraffins in concentrated solutions of the respective hydrates) are slowly mixed with bromine, the brom-nitro-paraffins separate as distillable oils; e.g. There is invariably, however, some dibrom-nitro-ethane: obtained at the same time. CH3.CBr2NO, By treatment of a slightly heated alcoholic solution of a nitroparaffin with acetic acid and iron filings, reduction to the acetate of a primary amine occurs: (CnH2n+1)NO2 + 3Fe + 7HO.C2H30= 3Fe(O.C2H30)2 + 2H2O +(CnH2n+1)NH3.O.C2H2O, from which on distillation with an alkali the primary amine is obtained. 290. The following compounds have so far been obtained : H Nitro-methane, CH3.NO,H-C-H, a colourless mobile liquid 0=N=0 little soluble in water and which boils at 99°–101°. It is also obtained by heating a mixture of concentrated solutions of potassic monochlor acetate and nitrite : CH,Cl 2 | CO.OK + 2KNO2+ H2O = 2KCl + K2CO3 + CO2 + 2CH3.NO 2, the nitro-methane distilling over with the water vapour. If nitromethane be poured into an alcoholic solution of sodic hydrate, a colourless precipitate of sodium nitro-methane alcoholate : CH2.NaNO2,C2H6O, is obtained, which by long exposure over sulphuric acid in vacuo is converted into a light white amorphous powder of sodium nitromethane, CH,Na.NO2. Mercuric nitro-methane, probably (NO2)CH2.Hg.CH2(NO)2, prepared by adding mercuric chloride to the aqueous solution of sodium nitro-methane, when in the dry state, explodes with fearful violence if rubbed with a dry body. 291. Nitro-ethane, CH3.CH2.NO2, is a colourless, agreeable-smelling oil, of sp. gr. 1.0582 at 13° and boiling at 113°-114°. Sodium nitro-ethane, CH3.CHNa. NO2, explodes violently on heating. It deliquesces in moist air. The aqueous solution gives with mercuric chloride white needles of the formula: CH3 Hg-Cl NO2 By treatment of a solution of sodium nitro-ethane with bromine, an oil is obtained which is a mixture of CH3 brom-nitro-ethane, CHBr2 (boiling at 145°-148°); and NO2 dibrom-nitro-ethane, CBr, (boiling at 162°-164°). 292. Nitro-propane, CH3.CH2.CH,.NO2, and nitro-isopropane, CH3CH.NO, are colourless mobile liquids, insoluble in water. The first boils at 125°-127°, the latter at 112°-117°. Both yield with alcoholic solution of sodic hydrate precipitates: CH3.CH2.CHNA.NO, and which detonate at higher temperatures. CH3 CH3CH.CH.CH2.NO2, boils at 150°-160°, Nitro-isopentane, CH and, as already mentioned, does not yield metallic derivatives. PHOSPHORUS COMPOUNDS OF THE ALCOHOL RADICALS. 293. Similarly to the derivation of the amines from ammonia, phosphoretted hydrogen, PH3, yields alkylic phosphine bases. These latter show the property of uniting with acids only in a very diminished degree, the power of uniting with acids decreasing with increased replacement of hydrogen by alcohol radicals. The bodies belonging hereto form the following groups: Primary phosphines, P(CnH2n+1)H2, corresponding to N(CnH2n+1)H2. P(CnH2n+1)2H P(CnH2n+1)3 Secondary The trivalent phosphorus compounds are distinguished from the corresponding ammonia derivatives by their ready oxidisability, absorbing oxygen by mere exposure to air, often with spontaneous inflammation. The tertiary phosphines yield oxides of the formula P(CnH2n+1)30; the primary and secondary phosphines oxidising to phosphinic acids, P(CnH2n+1)2O.OH and P(CnH2n+1) 2n+1)O(OH)2. THE ALKYLIC PHOSPHINES. 294. Whilst by action of ammonia on alkylic iodides the main products of the reaction are primary amines, by passing PH, into heated alkylic iodides no primary or secondary phosphines are formed, but only tertiary and quaternary phosphonium iodides. The result is just the same in the reaction between phosphonic iodide, (PHI), and alkylic iodides. In order to obtain the primary and secondary phosphines, the reaction between the two last-mentioned bodies must take place in presence of zincic oxide. In order to prepare these bodies, two molecules of phosphonic iodide, one molecule of zincic oxide, and two molecules of the alkylic iodide are heated in sealed glass tubes to 150° for six to eight hours. The tube, when cold, contains a crystalline mass, which consists of the hydrides of the primary and secondary phosphines in union with zincic iodide. The reactions are expressed by the following equations: ZnO + 2PH,I + 2C2H2n+1I = ZnI2 + 2P(CnH2n+1)H3I + OH2, and ZnO + PH,I + 2CnH2n+1I= ZnI2 + P(CnH2n+1)2H2I + OH2. From this mixture the primary and secondary phosphine can be readily separated from one another, and obtained in the pure state by means of the decomposition of the primary phosphonic salt by water: P(CnH2n+1)H3I + xH2O = (HI + ≈H2O) + P(С2H2n+1)H2, in similar manner to: PH,I+ H,0 = (HI+ æH,O) + PHg. The secondary phosphonic salts are not altered by water, but are decomposed by alkaline hydrates. In consequence of the spontaneous inflammability of the phosphines the decomposition must be carried on in vessels filled with dry hydrogen. The products from several tubes are for this purpose placed in a flask A standing on a sand bath (fig. 18). The flask is provided with two tubes fixed into its neck, of which the under B, bent slightly |