The Chemistry of Powder and Explosives - Sciencemadness Dot Org

TRIXITROXYLENE 153
Dautriche found the density of powdered and compressed TNT
to be as follows:
PRESSURE: KILOS PER SQUARE CENTIMETER
275
685
1375
2060
2750
3435
4125
DENSITY
1.320
1.456
1.558
1.584
1.599
1.602
1.610
Trinitrotoluene was prepared by Wilbrand 39 in 1863 by the
nitration of toluene with mixed acid, and in 1870 by Beilstein
and Kuhlberg 40 by the nitration of o- and p-nitrotoluene, and by
Tiemann 41 by the nitration of 2,4-dinitrotoluene. In 1891 Haus-
^ermann 42 with the Griesheim Chem. Fabrik undertook its manufacture
on an industrial scale. After 1901 its use as a military
explosive soon became general among the great nations. In the
fir.«t World War all of them were using it.
Trinitroxylene (TNX)
In m-xylene the two methyl groups agree in activating the
same positions, and this is the only one of the three isomeric
xylenes which can be nitrated satisfactorily to yield a trinitro
derivative. Since the three isomers occur in the same fraction of
coal tar and cannot readily be separated by distillation, it is
necessary to separate them by chemical means. When the mixed
xylenes are treated with about their own weight of 93 per cent
sulfuric acid for 5 hours at 50°, the o-xylene (b.p. 144°) and the
m-xylene (b.p. 138.8°) are converted into water-soluble sulfonic
acids, while the p-xylene (b.p. 138.5°) is unaffected. The aqueous
phase is removed, diluted with water to about 52 per cent acidity
calculated as sulfuric acid, and then heated in an autoclave at
130° for 4 hours. The m-xylene sulfonic acid is converted to
m-xylene, which is removed. The o-xylene sulfonic acid, which
remains in solution, may be converted into o-xylene by autoclaving
at a higher temperature. The nitration of m-xylene is conveniently
carried out in three steps. The effect of the two methyl
39 Ann., 128, 178 (1863).
w Ber., 3,202 (1870).
41 Ber., 3, 217 (1870).
42 Z. angew. Chem., 1891, p. 508; J. Soc. Chem. Ind., 1891, p. 1028.