NITRO DERIVATIVES OF TOLUENE 339Sapoihnikov (according to Gorst [2]) established that the losses of nitric acid
during the nitration of DNT to TNT amount to 70-75% due to oxidation processes,
the rest (25-30%) being due to evaporation of nitric acid.
Complete decomposition resulting from a vigorous nitration (with the loss of
ca. 5% of toluene) may lead to the formation of the products: NH 3 , CO, CO 2 ,
etc. [158] (p 76).
Reduction products of nitric acid, such as nitrogen and nitrogen oxides can also
be formed as the result of oxidation processes. Niederer [148] found that N 2 and NO
were not formed in the nitration of nitro- to dinitrotoluene, while they were present
in the nitration products of di- to tri-nitrotoluene. In addition to nitrogen and nitro-
gen oxide, carbon mono- and dioxide were formed in the last stage of nitration.
Their amount and the CO to CO 2 ratio increased with temperature.
According to Eastman [158] the percentage of CO may be sometimes so
high as to cause a gas explosion in the nitrator.
The break-down of the molecule, and the loss of the methyl group, may lead
to the formation of tetranitromethane during the nitration process. This substance
is always encountered in TNT as an impurity, and its presence can be established
by its characteristic smell reminiscent of that of nitrogen oxides.
It has been suggested that tetranitromethane increases the sensitiveness of TNT
to impact, friction and high temperature. That is, why the removal of this impurity
is very advisable, the more so because in the course of time it transforms into
nitroform, CH(NO 2 ) 3 , an acid substance readily yielding salts which are sensitive
to thermal and mechanical stimuli. The simplest way of removing tetranitromethane
consists in treating it with sodium sulphite, which reacts in the following way:C(NO 2 ) 4 + Na 2 SO 3 -> C(NO 2 ) 3 SO 3 Na + NaNO 2 (33)The sodium salt of trinitromethanesulphonic acid is readily soluble in water.
It is unstable and, according to Muraour [103], undergoes further hydrolysis:
C(NO 2 ) 3 SO 3 Na + H 2 O -> CH(NO 2 ) 3 + NaHSO 4 (34)According to Kostevitch [159] tetranitromethane can be responsible for the
formation of “tarry matters“.
TETRANITROTOLUENE
m.p. 136.5°C