Process for working up side products of the dinitrotoluene production

摘要

Organic secondary components formed during nitration of toluene to dinitrotoluene are removed by combining acidic and alkaline wastewater resulting from a washing step of a nitration process, and an aqueous distillate from a sulfuric acid concentration step such that the resultant mixture has a pH below 5; separating the resultant aqueous and organic phases by phase separation; and recycling the organic phase into the nitration process. Removal of organic secondary components formed during nitration of toluene to dinitrotoluene includes combining acidic and alkaline wastewater resulting from a washing step of a nitration process, and an aqueous distillate from a sulfuric acid concentration step such that the resultant mixture has a pH below 5; separating the resultant aqueous and organic phases by phase separation; and recycling the organic phase from the separating step into the nitration process. The organic secondary components are present in the acidic and alkaline wastewater from the dinitrotoluene washing step and in the aqueous distillate from the sulfuric acid concentration step, together with small amounts of mononitrotoluene and dinitrotoluene.