Patent ID: 7217818
Filing Date: 2007-05-15
Classification: C07D

Abstract:
1. A process for removing high boilers from crude caprolactam which comprises high boilers and caprolactam, and which has been obtained by a) reacting 6-aminocapronitrile with water to give a reaction mixture, b) removing ammonia and unconverted water from the reaction mixture to obtain crude caprolactam, and c) feeding the crude caprolactam to a distillation apparatus to obtain a first substream via the top containing caprolactam product and a second substream via the bottom by setting the pressure in the distillation such that the bottom temperature does not go below 170° C., and adjusting the second substream such that the caprolactam content of the second substream is not less than 75% by weight, based on the entire second substream.