344 



Dr. Hofmann's Researches on the 



[June 16, 



The preceding analyses appear to estabUsh beyond a doubt the com- 

 position of aniline-blue ; and I do not hesitate to maintain the formula 

 originally established by me as the true expression of the constitution of 

 this compound. 



The resumption of this inquiry has led me to some observations which 

 afford an additional support of the composition of aniline-blue. 



Rosanilinej when submitted to dry distillation, undergoes an irregular 

 decomposition. Ammonia is evolved, a large amount of hquid bases (from 

 40 to 50 per cent.) passes over, and a porous mass of charcoal remains in 

 the retort. The principal constituent of the liquid product is aniline. 



Ethyl-rosaniliney the commercial aniline- violet, already manufactured 

 on a large scale by Messrs. Simpson, Maule, and Nicholson, when distilled, 

 exhibits similar phenomena. There is no difficulty in separating from the 

 liquid product an appreciable amount of ethylaniline, the presence of which 

 has %een established by the examination of the platinum^salt. 



The relation existing between aniline -violet, obtained by the action of 

 iodide of ethyl, and aniline-red, cannot possibly be doubtful. Now, since 

 analysis points out similar relations between aniline-blue and aniline-red, it 

 became perfectly legitimate to anticipate, among the products of distilla- 

 tion of aniline-blue, i. e. of phenylated rosaniline, the presence of pheny- 

 lated aniline^ or diphenylamine^ a substance which chemists had often, but 

 vainly, endeavoured to prepare. Experiment has verified this anticipa- 

 tion. 



Some weeks ago my friend, M. Charles Girard, Director of the "Works 

 of the Fuchsine Company at Lyons, had the kindness to transmit to me 

 for examination some basic oils of high boiling-point which he had obtained 

 by the destructive distillation of a considerable quantity of anilirie-blue. 

 The product of distillation which he forwarded to me was brown and viscid. 

 When rectified, it furnished a slightly coloured liquid ; at 300° the thermo- 

 meter indicated the distillation of a definite compound. 



The distillate which had passed between 280° and 300° soHdified on 

 addition of hydrochloric acid, a chloride difficultly soluble (more especially 

 in concentrated hydrochloric acid) being formed. By washing with alcohol, 

 and ultimately by crystallization from this liquid, the chloride was obtained 

 in a state of purity. When treated with ammonia, it furnished colourless 

 oily drops, which, after a few moments, solidified to a white crystaUine 

 mass. 



The crystals thus obtained possess a peculiar flower-like odour ; their 

 taste is aromatic, and afterwards burning. At 45° they fuse to a yellowish 

 oil, distilling constantly, and without alteration, at 312° (corr.). They are 

 almost insoluble in water, easily soluble in alcohol and ether. Neither in 

 aqueous nor in alcoholic solution has the substance any alkaline reaction. 

 When brought into contact with concentrated acids, the crystals are converted 

 into the corresponding salts, which are remarkable for their instability. On 

 the addition of water, the base separates in oily drops, rapidly solidifying to 



