Hexanitrodiphenylamine preparation

A,A -Bis(3-aminopicryl)-l,2-ethanediamine (108) (m.p. 275 °C) is prepared from the reaction of ethylenediamine with two equivalents of 3-chloro-2,4,6-trinitroaniline. " The same chemists reported 3,3 -diamino-2,2 4,4, 6,6 -hexanitrodiphenylamine (109), a heat resistant explosive (m.p. 232-237 °C) prepared from the reaction of l,3-dichloro-4,6-dinitrobenzene with 3-chloroaniline followed by mixed acid nitration and subsequent chloro group displacement with ammonia. The potassium salt of 3,3 -diamino-2,2, 4,4, 6,6 -hexanitrodiphenylamine shows very high thermal stability. " ... 

Chemical properties. A chlorine atom ortho or para to a nitro group is especially reactive and is readily substituted. Numerous examples of such reactions, utilized in the preparation of explosives, are given later in the descriptions of preparation methods for dinitrophenol, dinitroanisole, hexanitrodiphenylamine, hexanitro-diphenyl sulphone, dinitroaniline, tetryl, etc. Chlorodinitrobenzene reacts with sodium sulphide and sulphur to yield sulphur dyes. The action of sodium disulphide results in the formation of tetranitrodiphenyl sulphide (p. 554). 

Gnehm [22] prepared hexanitrodiphenylamine by the nitration of diphenyl-amine with nitric acid, while Mertens [23] used a mixture of anhydrous nitric acid with concentrated sulphuric acid for the purpose. This method was applied in 1910 for the commercial preparation of hexyl. Since the yields obtained were too low (some 60% of the theoretical), during World War I a method patented in 1895 by the Griesheim Works was introduced, the starting materials being chlorodi-nitrobenzene and aniline. The method consists in the preparation of dinitrodi-phenylamine (m. p. 156-167°C) which is then nitrated in two stages, to obtain first tetranitrodiphenylamine (m. p. 199°C) and then hexyl ... 

This compound can be prepared from dinitrochlorobenzene and hydrazine. The tetranitrohydrazobenzene, which is obtained as an intermediate product, is treated with mixed acid, yielding hexanitroazobenzene by simultaneous oxidation and nitration. It is a more powerful explosive than hexanitrodiphenylamine. 

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