urbaf2

NITRO DERIVATIVES OF TOLUENE^327

136, 137] and their colleagues found that the η− isomer is also formed during the
nitration of m- nitrotoluene. Attempts to find the δ− and ε− somers in the products

of nitration of m- nitrotoluene were originally unsuccessful. These compounds were

obtained by an indirect method. Later de Beule [31] succeeded in obtaining all

isomers by nitrating m- nitrotoluene. His results are summarized in the dia-

gram (p. 328). The composition of crude TNT is according to de Beule: 95.1%

of α− isomer, 1.36% of β−, 2.69% of γ−, 0.002% of δ−, 0.29% of η− and 0.009%
of ε− isomer, and also unchanged 2,3-, 2,5- and 3,5-dinitrotoluenes in quantity

of 0.33, 0.15 and 0.06% respectively.

The nitration of m- nitrotoluene was also studied by Brady and his co-workers

[136-139] and by Drew [140].

PHYSICAL PROPERTIES

The physical properties of the unsymmetrical isomers of trinitrotoluene are

similar to those of α− trinitrotoluene. They are crystalline substances of a pale yellow

colour, soluble in most organic solvents, insoluble in water and non-hygroscopic.

Thermochemical properties...........................

Heat of crystallization. Garner and Abemethy [3] found the following values

for the heats of solidification of the β− and γ− isomers:

β− trinitrotoluene 5.0 kcal/mole

γ− trinitrotoluene 5.4 kcal/mole

Heat of combustion and heat of formation. The same authors give the following

values for unsymmetrical trinitro derivatives of toluene (Table 77).

TABLE 71

HEATS OF COMBUSTION AND FORMATION OF UNSYMMETRICAL ISOMERS OF

TRINITROTOLUENE

Heat of combustion

Isomer

(at constant volume)

with a correction for

nitric acid kcal/mole

β− trinitrotoluene 834.1

γ− trinitrotoluene 827.4

δ− trinitrotoluene 829.9

ε− trinitrotoluene 825.6

η− trinitrotoluene 827.1

Heat of formation

(for amorphous

carbon), kcal/mole

+16.9

+24.2

+21.7

+26.0

+24.5