196 Proceedings of the Royal Irish Academy. 



probably a small amount of 2-nitro-diphenylnitrosamine. When larger 

 amounts of nitric acid were employed, we found that the acetic acid solution 

 contained 2-4*8-10-tetranitro-diphenylaniine and 4 , 10-dinitro-diphenylamine 

 with other polynitro compounds, which we have uot been able to separate in 

 a pure condition. 



The dinitro-diphenylnitrosamine was decomposed with evolution of nitric 

 oxide when its solution in xylene was boiled under a reflux condenser, and 

 the chief product obtained by distillation of the xylene was 2-10-dinitro- 

 diphenylamine. 



0. X. Witt's dinitro-diphenylnitrosamine was a mixture of 2-10- and 

 4'10-dinitro-diphenylnitrosami] 



A cording to Juillard (loc. dt.) 2'10-dinitro-diphenylnitrosamine consists 

 of light rose-coloured leaves, melting with decomposition at 1 G0-1G2, while 

 4'10-dinitro-diphenylnitrosainine i-lnly orange-yellow 



prisms, melting with decomposition at 150 G. 



II. Wieland and II. Lecher (Liebigs Annalen cccxcii (1912), p. 107) state 

 thai 4 - 10-diuitro-diphenylnitrosamine is a yellow crystalline Bolid, melting 

 with decomposition at 159 . and showed thai when heated in boiling xylene 

 it Bplita oil' nitric oxide, forming 4'10-dinitro- and 2 , 4 - 10-triuitro-diphenyl- 

 ainines, with some tarry matter. It bad already been shown that the 



mpositiou of dinitro-diphenylnitrosaminefi d by heating 



witli aniline of alcoholic potash (0. N. Witt, Ber. d. I>tsch. Chem. lies, xi 



with alcohol and hydrochloric acid (Nietzki and Witt.. 



Ber. I. Dtsch. Chem Qes. xii (1>7'.'i p 1400), or with alcohol alone 



(.Itiillai 



In this laboratory, three apparently different diuitro-diphenylnitrosamines 

 11 of which are light-yellow in colour, melt with decom- 

 position, and mixtures of which, in pairs, mell several degrees lower than 

 either of ile- constituents. They all lose nitric oxide when heated, a property 

 the . hieh will pro a interest in connexion with the 



ibilised by addition of diphenyl- 

 ainine. 



experiments indicate that in the tbsence "i nitrous acid the diphenyl- 

 aiiiine is fin to its nitrate ind that so long as the amount of 



niti. equivalent to the diphenylamine, the colour 



ii'".' _ a. With tw [uivalents of nitric acid 



the colour cl b slowly from yellowish-green through dark green, and 



black-brown to red, and with larger amounts of the- acid the sane- col ■- 



chang lined more rapidly without the appearance al any time of the 



orange-yellow intermediate colour which has apparently ben observed. In 



