Melt crystallization process for preparing high trans, trans-isomer containing 4,4'-diisocyanato dicyclohexylmethane.

摘要

The present invention is directed for preparing a 4,4'-diisocyanato dicyclohexylmethane which contain a relatively high amount of the trans,trans-isomer. The process broadly comprises (a) melting a mixture of 4,4'-diisocyanato dicyclohexylmethane isomers, (b) cooling the melted mixture to form: (1) a liquid phase and (2) a solid phase , (c) removing said liquid phase, which is a commercially viable product itself, (d) heating the solid phase and removing that portion of the solid phase which has melted, and (e) recovering that portion of said solid phase which has not melted by heating the remaining portion. d