850 RUHEMANN AND ELLIOTT THE LXXL-The Isonitrile of PhenylhydTazine. By S. RUHENANN Ph.D. and W. J. ELLIOTT. ISONITRILES derived from hydrazines have not been carefully ex-amined and as such an investigation seemed desirable me under-took their examination and now communicate to the Society tlie results of our experiments on the isonitrile of phenylhydrazine. For the preparation of this isonitrile phenylhydrsziiie is dissolved in alcoholic potash and chloroform is carefully added to the solution. After heating in a water-bath for half an hour the flask is cooled the product diluted with water and shaken with ether. The -Lulaltered phenylhydrazine is removed from the ethereal solution of the iso-nitrile by shaking with very dilute sulphuric acid. On craporating the ethereal solution a brown oil remains which has a penetrating odour of isonitrile and partially solidifies on cooling.The crystal-line mass thus obtained is dissolved in alcohol from -which spherical aggregations of pale-yellow needles devoid of odour separate. The alcoholic filtrate almost entirely loses the odour of isonitrile on stand-ing for a few days and on evaporating the greater part of the alcohol deposits a small quantity of the same crystals while the fjltrate from these contains an uncrystallisable resin. The crystals thus obtained become quite white on recrystallising several times from alcohol. The pure substance melts at lSO" is easily soluble in chloroform carbon bisulphide and acetic acid as well as in alcohol and in ether but is insoluble in water and is not T-olatile in steam.The results of analysis indicate the empirical formula C7HGNZ :-Fonnd. 7 Calculated f o r r-dL-CiIIGN,. I. 11. C 71-08 - 71.19 5-46 - H 5.08 N 2373 - 23.89 100*0 ISONITRILE OF PHENPLHYDRAZINE. 831 Hence this substance has the percentage composition required for the isonitrile of phenylhydrazine C6H,*NH*NC ; but it is shown not to have this composition by the absence of the characteristic odour of the isonitriles and by its chemical behaviour. It is very probable that the crystals which melt at 180" are the result of a change which the initially formed isonitrile undergoes ; for in some preparations crystals did not separate out from the oil immediately after evapora-tion of the ether but only OD. standing for some time.It is possible that the stable Compound consisted of the normal cyanide C6H5*NH*CN and in that case me should have had the molecular transformation of an isonitrile into a normal nitrile taking place at a lower temperature than the corresponding change of the isonitriles of aniline and its homologues. In order to determine whether the substance obtained from phenylhydrazine was the normal nitrile its behaviour with acids and particularly with hydrochloric acid was studied. The compound when heated at 200" with hydrochloric acid in a sealed tube is only slightly altered. The tube contains bluish crystals which are soluble in alcohol leaving behind a small quantity of a blue residue with metallic lustre. White needles are deposited from the alcoholic solution which were proved to be the original compound by their melting point and by a nitrogen determination, which gave 23.94 per cent.of N. The substance undergoes no change on heating at 100" with alcoholic potash. Hofmann ( B e y . 17 1914 ; 18 1825) failed to convert the cyanides of tetra- and penta-methylaniline into the corresponding acids. Hence the stability of this compound towards hydrochloric acid does not conclusively prove that it is not a cyanide. Further investiga-tion however showed that we are here dealing with the representa-tive of another class of substances. We next proceeded to find the molecular weight ol the compound. This cannot be done by a vapour-density determination because partial decomposition takes place at the high temperature required for vaporisation.In consequence we employed Raoult's method of de-termining molecular weights and used for the purpose hhe sirnplc apparatns described by Holleman (Ber 21 860) which gave very satisfactory results. The solvent used was glacial acetic acid the freezing point of which was 14.39". 0.2931 gram of the substance dissolved in 18.9784 grams of acetic acid depressed the freezing point by 0*25", which corresponds to the molecular weight 240. It follows from this determination that the empirical formula derived from directl analysis should he doubled. The formula C14EI12N4 thus obtained requires a molecular weight of 236. Furthe 852 THE ISONITRILE OF PHENYLHTDRAZINE. confirmamtion of this formula is furnished by the behaviour of the substance with nitric and sulphuric acids.When a solution of the compound in glacial acetic acid is treated with fuming nitric acid a lemon-yellow crystalline precipitate forms at once. This is insoluble in water but soluble in boiling glacial acetic acid from which it separates on cooling in microscopic needles which melt at a temperature lying above 300". A nitrogen determination shows the compound to have the formula C I * H ~ N ~ * N ~ ~ -Calculated for Cl,HllN,.NOz. Found. N . 25.10 24-91 When the substance formed from phenylhydrazine is heated with concentrated sulphuric acid it dissolves ; if the heating is continued till no precipitate is formed immediately on the addition of water to a drop of the solution and the cold solution is then poured into water, tufts of white needles crystallise out on long standing.These crystals which contain sulphur are insoluble in alcohol benzene and chloroform only sparingly soluble i n cold water. After cry stailisation from hot water they give on analysis numbers which correspond to the formula CIIHllN4.HSO3. Found. CtLlculated for +7 CI4Hi1N,*HSO,. I. 11. - N . 17.36 17.72 s - 10.20 10.126 This substance therefore is a sulphonic acid. It forms an am-monium salt and a barium salt not easily soluble in water. The molecular weight as determined by Raoult's method together with the formation of the nitro-compound CIIH1lNI*NOZ and the sulphonic acid Cl~Hl1N4*HSO3 prove that the compound obtained from phenylhydrazine i n the manner described above has the formula c 14 H,,N*.When we consider the mode of formation and the chemical behaviour of the compound CI4Hl2N4 there can be scarcely any doubt that its constitution is expressed by the formula-CGH,*NH*N:C C :N*NH*C,H,. The pentad nitrogen of the isonitrile passes into the triad condition by the union of two molecules of the isonitrile CGH,*NH*NC ; whereas in all aromatic isonitriles known up to the present time the corre-sponding change takes place by the molecular transformation of the isonitrile into the normal nitrile SILICOY COMPOUNDS AND THEIR DERIVATIVES. 853 Further experiments with secondary as well as primary hydrazines are in progress in order to determine whether they show the same behaviour as phenylhydrazine. It is a pleasant duty for one of 11s (S. R.) to express his best thanks to Mr. R. H. Adie for the valuable help received from him at the commencement of the research. Uwiu e rsity Laboratory , Cam6 ridge