Process for the purification of caprolactam obtained from the depolymerization of polyamide-containing carpet

摘要

The present invention provides 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) removing substantially all of said water from said crude caprolactam and steam (c) distilling the resulting concentrated crude caprolactam at a pressure of less than about 8 mmHg and a temperature from about 110 DEG C. to about 145 DEG C. so as to form overheads and bottoms of the caprolactam; and (d) crystallizing the caprolactam overheads to obtain caprolactam crystals and mother liquor. The resulting purified caprolactam may then be used to make polycaprolactam which may then be used in engineered materials or spun into fiber.