CHAPTER XVIINITRO DERIVATIVES OF ANILINE
APART from tetryl, which is discussed in the chapter on nitramines (Vol. III),
the only aniline nitro derivative that has gained any considerable importance as
an explosive is hexanitrodiphenylamine, or hexyl. None of the other nitro deriv-
atives has proved of greater interest: though some achieved temporary importance
(as for example tetranitroaniline) or aroused a theoretical interest.
The introduction of nitro groups to a compound containing a NH 2 group
presents some difficulties, because of the high reactivity of this group and because
of the readiness of such compounds to undergo oxidation. Therefore, a nitro group
should be introduced into aniline or its homologues (other than N-substituted)
only after the amino groups had been protected by acylation, for example to ace-
tanilide.
A more modem method of preparation of nitroaniline derivatives consists in
using chlorodinitrobenzene as starting material. Advantage is taken of the reactiv-
ity of its chlorine atom which can be substituted by an amino group.MONONITRO DERIVATIVES OF ANILINE
Three isomeric nitroanilines: ortho- (m. p. 71.5°C), meta- (m. p. 114°C) and
para- (m. p. 148°C) are known.
Para-nitroaniline was obtained by A. W. Hofmann [1] who nitrated acetanilide
to p- nitroacetanilide which was then hydrolysed with a sodium hydroxide solution.
Khmer [2] found that acetanilide when nitrated also yields o- nitroacetanilide,
from which o- nitroaniline may be obtained by hydrolysis. The nitration of acetanilide