The Chemistry of Powder and Explosives - Sciencemadness Dot Org

TRINITROTOLUENE 141
not yet been developed. In dinitrochlorobenzene, however, the
chlorine is active. The substance yields dinitrophenol readily by
hydrolysis, dinitroaniline by reaction with ammonia, dinitromethylaniline
more readily yet by reaction with methylamine.
These and similar materials may be nitrated to explosives, and
the third nitro group may be introduced on the nucleus much
more readily, after the chlorine has been replaced by a more
strongly ortho-para orienting group, than it may be before the
chlorine has been so replaced. Dinitrochlorobenzene thus has a
definite advantage over picryl chloride. It has the advantage also
over phenol, aniline, etc. (from chlorobenzene by catalytic processes),
that explosives can be made from it which cannot be
made as simply or as economically from these materials. Tetryl
and hexanitrodiphenylamine are examples. The possibilities of
dinitrochlorobenzene in the explosives industry have not yet been
fully exploited.
Preparation of Dinitrochlorobenzene. One hundred grams of chlorobenzene
is added drop by drop to a mixture of 160 grams of nitric acid
{d. 1.50) and 340 grams of sulfuric acid (d. 1.84) while the mixture is
stirred mechanically. The temperature rises because of the heat of the
reaction, but is not allowed to go above 50-55°. After all the chlorobenzene
has been added, the temperature is raised slowly to 95° and is
kept there for 2 hours longer while the stirring is continued. The upper
layer of light yellow liquid solidifies when cold. It is removed, broken
up under water, and rinsed. The spent acid, on dilution with water,
precipitates an additional quantity of dinitrochlorobenzene. All the
product is brought together, washed with cold water, then several times
with hot water while it is melted, and finally once more with cold water
under which it is crushed. Then it is drained and allowed to dry at ordinary
temperature. The product, melting at about 50°, consists largely
of 2,4-dinitrochlorobenzene, m.p. 53.4°, along with a small quantity of
the 2,6-dinitro compound, m.p. 87-88°. The two substances are equally
suitable for the manufacture of explosives. They yield the same trinitro
compound, and the same final products by reaction with methylamine,
aniline, etc., and subsequent nitration of the materials which are first
formed. Dinitrochlorobenzene causes a severe itching of the skin, both
by contact with the solid material and by exposure to its vapors.
Trinitrotoluene (TNT, trotyl, tolite, triton, tritol, trilite, etc.)
When toluene is nitrated, about 96 per cent of the material
behaves in accordance with the rule of Crum Brown and Gibson.