Patent ID: 7851661
Filing Date: 2010-12-14
Classification: C07C

Abstract:
1. A process for preparing dinitrotoluene, comprising: a) reacting toluene with nitric acid in the presence of sulfuric acid to give a mononitrotoluene reaction mixture; b) separating the mononitrotoluene reaction mixture from a) in a dynamic separator into an organic phase comprising mononitrotoluene and an aqueous phase comprising sulfuric acid; c) reacting the organic phase comprising mononitrotoluene with nitric acid in the presence of sulfuric acid to give a dinitrotoluene reaction mixture; and d) separating the dinitrotoluene reaction mixture from c) into an organic phase comprising dinitrotoluene and an aqueous phase comprising sulfuric acid; wherein the mononitrotoluene reaction mixture from a) has a content of toluene of 3.5 to 8% by weight, based on the organic phase, and a content of nitric acid of from 0.1 to 1.2% by weight, based on the aqueous phase, and the phase separation in b) is effected in such a way that further reaction of the toluene with the nitric acid is prevented.