The Chemistry of Powder and Explosives - Sciencemadness Dot Org

158 AROMATIC NITRO COMPOUNDS
Germans used a mine explosive consisting of 56 per cent potassium
perchlorate, 32 per cent dinitrobenzene, and 12 per cent
dinitronaphthalene. 48 Their Tri-Trinal for small-caliber shells
was a compressed mixture of 2 parts of TNT (Tri) with 1 of
trinitronaphthalene (Trinal), and was used with a booster of
compressed picric acid.
Trinitronaphthalene appears to be a genuine stabilizer for
nitrocellulose, a true inhibitor of its spontaneous decomposition.
Marqueyrol found that a nitrocellulose powder containing 10 per
cent of trinitronaphthalene is as stable as one which contains 2
per cent of diphenylamine. The trinitronaphthalene has the further
effect of reducing both the hygroscopicity and the temperature
of combustion of the powder.
Hexanitrobiphenyl
2,2',4,4',6,6'-Hexanitrobiphenyl was first prepared by Ullmann
and Bielecki 49 by boiling picryl chloride in nitrobenzene solution
with copper powder for a short time. The solvent is necessary in
order to moderate the reaction, for picryl chloride and copper
powder explode when heated alone to about 127°. Ullmann and
Bielecki also secured good yields of hexanitrobiphenyl by working
in toluene solution, but found that a small quantity of trinitrobenzene
was formed (evidently in consequence of the presence
of moisture). Hexanitrobiphenyl crystallizes from toluene in
light-yellow thick crystals which contain y2 molecule of toluene
of crystallization. It is insoluble in water, and slightly soluble in
alcohol, acetone, benzene, and toluene, m.p. 263°. It gives a yellow
color with concentrated sulfuric acid, and a red with alcohol
to which a drop of ammonia water or aqueous caustic soda has
been added. It is neutral, of course, and chemically unreactive
toward metals, and is reported to be non-poisonous.
Hexanitrobiphenyl cannot 50 be prepared by the direct nitration
48 Naoum, "Schiess- und Sprengstoffe," Dresden and Leipzig, 1927, p. 62.
i9 Ber., 34, 2174 (1901).
60 The effect may be steric, although there is evidence that the dinitrophenyl
group has peculiar orienting and resonance effects. Rinkenbach and
Aaronson, J. Am. Chem. Soc, 52, 5040 (1930), report that sj/wi-diphenylethane
yields only very small amounts of hexanitrodiphenylethane under
the most favorable conditions of nitration.