公开(公告)号：DE2933601A1

公开(公告)日：1981-03-12

申请号：DE2933601

申请日：1979-08-18

Applicant: BASF AG

Inventor： KRUEGER SIEGFRIED ,  SCHMIDT RUDOLF DIPL ING DR ,  SAUER FRIEDRICH ,  STEEN JAAK VAN ,  PEE WILLY VAN DIPL CHEM DR ,  OHLINGER RAINER DIPL CHEM DR ,  BRANDTSTAEDTER HORST DR ,  ASTHMEIER HANS-JOACHIM DIPL CH

IPC: B01D3/10 ,  C07C20060101 ,  C07C265/12 ,  C07C119/048

Abstract: A process for the manufacture of 4,4'-diphenylmethane diisocyanate and a mixture of diphenylmethane diisocyanate isomers containing a controllable amount of uretdione and hydrolizable chlorine which comprises feeding crude MDI to an evaporator, condensing a head fraction in two stages in the presence of an inert gas, feeding the first stage condensate to a distillation column, producing a mixture of diphenylmethane diisocyanate isomers as an overhead, producing 4,4'-diphenylmethane diisocyanate as a side draw, and condensing each of the overhead and side draw in two stages in the presence of an inert gas.