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NITRO DERIVATIVES OF AZO- AND HYDRAZO-BENZENES 575

The process is carried out in water suspension in the presence of agents to bind

the hydrogen chloride evolved.

Hexanitroazobenzene is a more powerful explosive than hexyl, being of the same

order as tetryl. Sensitivity to impact is also similar to that of tetryl.

HEXANITROHYDRAZOBENZENE

The compound (m. p. 210-202°C) was first obtained by Grandmougin and

Leeman [2] in 1908. They reacted picryl chloride with hydrazine. The product is

rather reactive: for example, its aci-form

readily forms salts with metals. It can also be oxidized to hexanitroazobenzene

and in the presence of aniline internal oxidation to a phenazine compound takes

place. That is why it has not been regarded as an explosive of any practical value.

The same holds for pentanitrohydrazobenzene C 6 H 3 (NO 2 ) 2 NH-NHC 6 H 2 (NO 2 ) 3 ,

which may be obtained by reacting picryl chloride with dinitrophenylhydrazine.

NITRO DERIVATIVES OF AZOXYBENZENE

Nitration of azoxybenzene may lead to the formation of various nitro deriva-

tives, differing in the number of nitro groups.

MONONITRO DERIVATIVES

Thus, when nitrated with nitric acid alone (sp. gr. 1.45) azoxybenzene yields

a mixture of 2- and 4-nitroazoxybenzenes (I) and (II) (Zinin [3] ; Werner and Stias-

ny [1]).
The 4-isomer has two crystalline forms IIa and IIb (Angeli and Alessandri [4];

Angeli and Valori [5]).

1

m. p. 49°C

II

m. p. 153°C (IIa)

149°C (IIb)