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.

公开(公告)号：DE2914671A1

公开(公告)日：1980-10-23

申请号：DE2914671

申请日：1979-04-11

Applicant: BASF AG

Inventor： WOLF DIETER DIPL ING DR ,  SCHMIDT RUDOLF DIPL ING DR ,  BLOCK ULRICH DIPL ING DR ,  SCHOENMAKERS HARTMUT DIPL PHYS ,  BOTT KASPAR DIPL CHEM DR ,  KAIBEL GERN DIPL ING

IPC: C07C53/02 ,  C07C27/02 ,  C07C51/00 ,  C07C51/09 ,  C07C51/42 ,  C07C51/44 ,  C07C51/48 ,  C07C67/00

Abstract: Anhydrous or substantially anhydrous formic acid is obtained by hydrolysis of methyl formate, in a process wherein (a) methyl formate is hydrolyzed, (b) the methanol and excess methyl formate are distilled from the hydrolysis mixture obtained, (c) the bottom product of distillation (b), consisting of formic acid and water, is extracted, in a liquid-liquid extraction, with an extractant which in the main takes up the formic acid, (d) the resulting extract phase, consisting of formic acid, the extractant and a part of the water, is subjected to distillation, (e) the top product obtained from this distillation and consisting of all or part of the water introduced into the distillation, and part of the formic acid, is recycled, as vapor, into the lower part of the distillation column of stage (b), (f) the bottom product of distillation stage (d), consisting of the extractant, with or without part of the water, and the greater part of the formic acid, is separated by distillation into anhydrous or substantially anhydrous formic acid and the extractant, and (g) the extractant leaving stage (f) is recycled to the process.