| 摘要 |
FIELD: chemistry.SUBSTANCE: invention relates to a method for simultaneous and continuous production of two different mixtures of predominantly 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate. The method includes a step of separating a mixed diphenylmethane diisocyanate isomer feed stream [MIx] by a single-step suspension melt crystallisation process into two mixed isomer diphenylmethane diisocyanate streams [Miy and Miz] wherein x ranges from 60 to 80, y ranges from 80 to 95 and z ranges from 48 to 54, where x, y and z are percentages by weight of the 4,4'-diphenylmethane diisocyanate isomer contained in the diphenylmethane diisocyanate mixture. Temperature of the suspension exiting the crystallisation section is kept on a level from about 18°C to 20°C.EFFECT: method enables to obtain streams of diisocyanates of the diphenylmethane series of a defined composition.2 cl, 11 dwg, 4 ex |
