CHAPTER XVIIINITRO DERIVATIVES OF AZO- AND HYDRAZO-BENZENES
NITRATION of azo compounds leads to mixtures of nitro derivatives of azo and
azoxy compounds (Werner and Stiasny [l]). Thus, by nitrating azobenzene with
98% nitric acid at a temperature not exceeding +6°C, these authors obtained
a mixture of p- nitroazobenzene, p,p'- dinitroazobenzene and p- nitroazoxybenzene.
With 98% nitric acid without cooling, mainly a mixture of the trinitroazoxybenzene
isomers was obtained.
HEXANITROAZOBENZENE
2,2’,4,4’,6,6’-Hexanitroazobenzene (m. p. 215-216°C) forms orange coloured
needles. It was prepared by Grandmougin and Leeman [2] by acting with hydra-
zine on picryl chloride. In a more recent method chlorodinitrobenzene is reacted
with hydrazine to yield tetranitrohydrazobenzene which is then further nitrated.
Simultaneously the oxidation of the hydrazo to an azo group takes place:
(1)