Patent ID: 6187917
Filing Date: 2001-02-13
Classification: C07D

Abstract:
A process for the preparation of purified caprolactam comprising the steps of:(a) depolymerizing polyamide-containing carpet in the presence of steam to obtain crude caprolactam and steam;(b) condensing or distilling said crude caprolactam and steam to form aqueous crude caprolactam comprising at least ten percent by weight water;(c) removing substantially all floating oil from said aqueous crude caprolactam so as to form a substantially floating oil-free aqueous crude caprolactam;(d) removing substantially all of said water from said substantially floating oil-free aqueous crude caprolactam;(e) distilling the resulting concentrated crude caprolactam at a pressure of less than about 8 mmHg and a temperature from about 110.degree. C. to about 145.degree. C. so as to form overheads and bottoms of said caprolactam; and(f) crystallizing said caprolactam overheads to obtain caprolactam crystals and mother liquor.