314 CHEMISTRY AND TECHNOLOGY OF EXPLOSIVES
Orlova [2a] also studied the change in rate of nitration of dinitrotoluene under
the action of stirring. The reaction was carried out with a nitrating mixture containing
16% HNO 3 , 81% H 2 SO 4 ; ratio nitrating mixture/dinitrotoluene = 1.5, tem-
perature 90°C, time 40 min. Orlova found that above a certain rate of stirring no
improvement of the yield was obtained (Fig. 67).
% H 2 SO 4FIG. 66. Influence of the concentration of
sulphuric acid on the rate of nitration in
homogeneous conditions (nitrating mixtures
with a high content of HNO 3 , Orlova [2a]).
FIG. 67. Influence of the rate of
stirring on the rate of nitration
of DNT (Orlova [2a]).FIG. 68. Solubility of DNT and its molten mixtures with TNT in sul-
phuric acid of various concentrations (Orlova [2a]).Another important factor governing the nitration of dinitrotoluene is the dis-
tribution of dinitrotoluene between the two phases: the organic phase consisting
of trinitrotoluene (and dinitrotoluene) and the acid phase. The solubility of
2,4-dinitrotoluene in concentrated sulphuric acid is considerably diminished when
20-30% of trinitrotoluene is dissolved in the dinitrotoluene. Further addition of
trinitrotoluene reduces the solubility to a lesser extent. This can be seen from Table
70 and Fig. 68.