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560 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVES

(1)

Ib

Acidification of I regenerates picramide.
If instead of ammonia a primary amine NH 2 R is used N-substituted picra-

mides are formed through an intermediate IIa or IIb:

IIa IIb

TETRANITROANILINE

2,3,4,6-Tetranitroaniline (m. p. 215°C, decomposition) is a yellowish crystalline

substance, difficult to dissolve in most of organic solvents but soluble in acetone

(17 parts in the boiling solvent) and o- nitrotoluene (some 33 parts at 140°C).

Tetranitroaniline was first obtained by Flürscheim [19, 19a], who proposed

its use as an explosive because its properties were similar to those of tetryl. For the

preparation of tetranitroaniline Flürscheim nitrated m- nitroaniline with a mixture

of concentrated acids at 70-80°C. The yield was 64-69% of the theoretical (from

100 kg of m- nitroaniline only 130-140 kg instead of 204 kg could be obtained).

Tetranitroaniline is a rather unstable compound. Thus, when boiled with water

its meta- nitro group undergoes hydrolysis to a phenolic group (II), while on boiling

with methyl- or ethyl alcohol it yields an anisole- (III) or phenetole derivative (IV),

which with ammonia may form trinitro-m-phenylenediamine (V):