Ryan and Ryan — Action of Acids on Diphenylamine. 195 



From 2-nitro-diphenylnitrosaniine and nitric acid 1'. Juillard (loc. cit.) 

 obtained a mixture of 2"8- and 2"10-(liiiitro-diphenylnitrosaniines, and the 

 same chemist, by heating 2-nitro-diphenylnitrosainine with acetic acid, 

 prepared 2 - 8- and 2-10-dinitro-diphenylamines. 



By further nitration of 210-dinitro-diphenylamine Juillard obtained 

 24-8-trinitro-diphenylamine and 2"4"10-trinitro-diphenylamine. while Norton 

 and Allen (Ber. d. Dtsch. Cheni. Ges. xviii 1885), p. 1997), by boiling acetyl- 

 diphenylamine with diluted nitric acid, prepared a trinitro-dipbenylamine 

 melting at 135° C, which is probably a mixture of polynitro-diphenyl- 

 amines. 



No tetranitro-diphenylamine has been hitherto obtained by the direct 

 nitration of diphenylamine. Gnehm and Wys (Ber. d. Dtsch. Chem. Ges. x 

 (1877), p. 1319), by the action of nitric acid on a hot acetic acid solution of 

 diphenylnitrosamine, obtained a "tetranitro-diphenylamine "melting at 192°C., 

 which we have found to be somewhat impure, 2 , 4 - 8 - 10-tetranitro-diphenyl- 

 amine. 



Pure 2-4'S'lO-tetranitro-diphenylaniine was obtained by Ame Pictet and 

 E. Klein Arch. d. Sciences phys. et nat., Geneve (4) xvi (1903), pp. 191-212) 

 by the action of diacetyl-nitric acid on acetyl-diphenylamine, and by 

 P. Juillard (loc. cit.) by the nitration of 4'10-dhritro- and 24'10-trinitro- 

 diphenylamines in the presence of diphenyl-nitrosamine. 



Gnehm (loc. cit. ; cf. Mertens (Ber. d. Dtsch. Chem. Ges. xi (1878), p. 845) 

 by warming diphenylamine with nitric acid, prepared 2 - 4 , 6"8 , 10 - 12-hexanitro- 

 diphenylamine. 



In our experiments, which were all carried out at the laboratory tempe- 

 rature and at low concentrations, we have found that prolonged action of 

 equivalent amounts of diphenylamine and nitric acid forms only the nitrate 

 of the base, and that when more than one equivalent of the acid is taken, one 

 portion of the amine is converted into a brown resinous solid, and another 

 portion into nitro-derivatives of diphenylamine, amongst which we have, up 

 to the present, been able to identify 210-dinitro-diphenylamine, 410-dinitro- 

 diphenylamine, and 2 - 4 - ST0-tetranitro-diphenylamine. In one experiment (4) 

 a trace of 2T0-dinitro-diphenylnitrosamine was obtained. 



Under the same conditions the nitration of diphenylnitrosamine proceeded 

 in an entirely different manner. The colour of the solution changed slowly 

 from orange to orange-yellow, or yellow with separation of the sparingly 

 soluble 2-10-dinitro-diphenylnitiosamine, in the case of all solutions containing 

 two or more equivalents of nitric acid to one of diphenylnitrosamine. The 

 dinitro-nitrosamine was not formed when only one equivalent of acid was 

 employed, the products in this case being 4-nitro-diphenyluitrosamine with 



