| abstract |
The present invention relates to a process for cleaning a crude mixture comprising dinitrotoluene, nitric acid, nitrogen oxides and sulfuric acid obtained by nitration of toluene after separation of the nitric acid, comprising two cleaning steps (WS-I) and (WS- II), wherein i) In a first rinse step (WS-I), the crude mixture is extracted with cleansing acid I comprising nitric acid, nitrogen oxides and sulfuric acid by a cleansing comprising at least one extraction step, wherein the first cleansing step (WS- The cleaning acid discharged from the first extraction stage (WS-I-1) of the present invention has a total acid content of 20 to 40% by weight, obtaining a premilled cleaned crude mixture, ii) In a second cleaning step (WS-II), the pre-cleaned crude mixture comprising dinitrotoluene is extracted with cleansing acid II in a wash comprising at least one extraction stage, wherein the second cleansing step (WS- (WS-II-1) of the present invention has a pH of 4 or less, and a mixture comprising dinitrotoluene substantially free of nitric acid, sulfuric acid and nitrogen oxides is obtained . |