urbaf2

NITRO DERIVATIVES OF TOLUENE 305

of the induction period (i.e. the period of time elapsing between the application

of heat to the sample and the moment of explosion), brought about by the addition
of foreign matter to trinitrotoluene (Table 68).

TABLE 68

INFLUENCE OF ADMIXTURES ON THE INDUCTION PERIOD OF THERMAL

DECOMPOSITION OF α− TRINITROTOLUENE

Admixture

Temperature

°C

Diminution of the

induction period, t,

by sec

1.9% of Fe 2 O 3

11% of ferro-a-nitroso-

p- naphthol complex

9% of diphenylamine

(^297) 3.9
276 45
287 14
The induction period for pure trinitrotoluene at 275°C is 12 min and at 328°C-
50 sec.
As T. Urbanski and Pillich [93] found, the addition of sulphur to TNT causes
the initiation temperature to fall. This can be seen from the following data:
Sulphur content, % Initiation temperature, °C
Pure TNT 333
5 304
10 294
20 284
30 275
The explosion caused by heating TNT to which 5-10% of sulphur has been
added is more violent than the explosion of pure TNT.
Investigations on the influence of metals on TNT are of special importance.
Extensive studies on the effect of lead, aluminium and iron on TNT in the presence
of nitric acid were carried out by Kovache and Thibon [94] as early as in 1918.
These investigators found, that when heating TNT with chips of lead, aluminium
or iron in the presence of nitric acid diluted with water to a concentration of about
13% of HNO 3 , a product was formed which contained a considerable proportion
of the metal, and which was insoluble in toluene, inflammable and sensitive to
friction and impact. The products of the reactions of TNT with lead and iron were
particularly sensitive. They also could be ignited when heated with nitric acid or
with mixtures of nitric and sulphuric acids.
The constitution of these products has not been determined. It is possible that
they arc mixtures of complex compounds of various composition. The lead content
in the product obtained in the reaction with lead provides evidence of variable com-