PROCESS FOR THE SIMULTANEOUS PRODUCTION OF DIFFERENT MIXTURES OF DIISOCYANATE ISOMERS OF THE DIPHENYLMETHANE SERIES

摘要

Process for the simultaneous and continuous production of two different mixtures of predominantly 4,4'-MDI and 2,4'-MDI in a single-step suspension melt crystallisation process whereby a mixed diisocyanate feed stream [MIx] is used to produce simultaneously two mixed diisocyanate streams [MIy and MIz] wherein x = 80 to 92, y = 97 to 99 and z = 60 to 80 preferably x = 82 to 88, y = 97.2 to 98.5 and z = 63 to 70 where x, y and z are percentages by weight of the 4,4'-MDI isomer contained in the diisocyanate isomer mixture.