The Chemistry of Powder and Explosives - Sciencemadness Dot Org

146 AROMATIC NITRO COMPOUNDS
which are readily soluble in water. After the reaction, the purified
material is washed with water until the washings are colorless.
Muraour 24 believes the sulfite process for the purification of
TNT to be an American invention. At any rate, the story of its
discovery presents an interesting example of the consequences of
working rightly with a wrong hypothesis. The nitro group in the
m-position in /3- and y-TNT is ortho, or ortho and para, to two
other nitro groups, and accordingly is active chemically. It is
replaced by an amino group by the action of alcoholic ammonia
both, in the hot 23 and in the cold, 26 and undergoes similar reactions
with hydrazine and with phenylhydrazine. It was hoped
that it would be reduced more readily than the unactivated nitro
groups of a- or symmetrical TNT, and that the reduction products
could be washed away with warm water. Sodium polysulfide was
tried and did indeed raise the melting point, but the treated
material contained finely divided sulfur from which it could not
easily be freed, and the polysulfide was judged to be unsuitable.
In seeking for another reducing agent, the chemist bethought
himself of sodium sulfite, which, however, does not act in this
case as a reducing agent, and succeeded perfectly in removing
the /3- and y-TNT.
The reaction consists in the replacement of the nitro by a
sodium sulfonatc group:
CH3
NO,
CH3
•^N-NO,
+ NaNO,
, J-SO2—ONa
NO2
and
CH3
|
J-NO, -
CH,
|
L J-SO2—ONa
NO,
NO2
"Bull. soc. chim., IV, 35, 367 (1924); Army Ordnance, 5, 507 (1924).
25
Hepp, Ann., 215, 364 (1882).
26
Giua, Alti accad. Lincei, 23, II, 484 (1914); Gazz. chim. ital., 45, I,
345 (1915).