manufacturing method of m- toluene diamine or m- toluene diisocyanate

摘要

Toluenediamine is produced and separated from by-products of the reaction by: a) hydrogenating dinitrotoluene in the presence of a catalyst, b) separating the catalyst, water and optionally solvent from the hydrogenation reaction mixture to give crude toluenediamine, and c) separating by distillation the crude toluenediamine in a separating wall column into at least four product streams P 1 , P 2 , P 3 and P 4 . The product stream P 1 is a stream containing low boilers. The product stream P 2 is a stream containing o-toluenediamine. The product stream P 3 is a stream containing m-toluenediamine. The product stream P 4 is a stream containing high boilers and m-toluenediamine.