198 Proceedings of the Royal Irish Academy. 



Experimental. 



A. — Action of Nitric Acid on Diphenylamine. 



1. To a solution of 2 grams of diphenylamine in 100 c.cs of glacial acetic 

 acid 07 c.c. (1 mol.) of nitric acid (sp. g. T43) was added, and the solution 

 was allowed to remain in a stoppered tlask at the laboratory temperature for 

 six weeks. The mixture developed a greenish-yellow colour during the first 

 ten days, and this, after gradually becoming green during the succeeding ten 

 days, then remained green without separation of any solid until the end of 

 the sixth week. 



The green solution was poured into 400 c.cs of water, and the mixture 

 was shaken in a Bask until the liquid above the precipitated solid was clear. 

 The h crystals, which were filtered, weighed very nearly 2 grams. 



When : ized from ale.. In. 1 in which they were very soluble, they 



melted at 53-54 C, were white in colour, and proved to be diphenylamine. 



2. A solution of diphenylamine, similar to the last, to which 1*4 ces (2 mols.) 

 of nitric acid had been added, developed a greenish-yellow colour in the first 

 week, and a green colour during the succeeding fortnight. Its colour then 

 changed very slowly through dark-green to red. the lal Lei colour beiug retained 

 until tin- end of tl speriment. 



The brown resinous solid which separated from the solution from the 



mteenth day onwards was filtered after eleven weeks, and reserved; the 

 filtrate was poured into three or four volumes of water. The yellow, oily solid 

 which was precipitated melted at 135 145 0., when purified several times 

 from alcohol and chloroform. We did not, however, succeed in separating it 

 into its components. 



•''. [n our nexl experiment we added an amouul (2-1 c.cs) of nitric acid, 

 corresponding to three molecular proportions ol the acid, to a diphenylamine 

 solution of the same concentration as the last, and observed changes in the 

 colour of the solution similar to those just i during the eleven weeks 



the experiment continued. 



The brown solid, which bad separated, was filtered, and the oily solid, 

 which separated from the filtrate on the addition of water, was filtered and 



med first with alcohol, afterwards with chloroform. The undissolved solid 



Was found alter el ystalli/at |n|i from acetone to be 2'4'8"] (I-/, I r,i iiitra-i li/ilii-ii ///- 



amine; but the more soluble substance which was contained in the chloroform 

 filtrate was not isolated in a pure condition. 



4. To another soltiti f 2 grams ol diphenylamine in 1 On c.cs of glacial 



acetic acid we added 2*8 c.cs 4 moh.) of nitric acid, and again allowed the 

 mixture to remain in a Btoppered tlask at the room temperature. 



