Obtaining caprolactam by cleavage of molten polycaprolactam

US5455346A · kind A · utility

Assignee

• BASF SE

Inventors

• Michael Kopietz · Frankfurt, DE
• Ulrich Kalck · Schifferstadt, DE
• Simon Jones · Leimen, DE
• Peter Bassler · Viernheim, DE
• Claus-Ulrich Priester · Ludwigshafen, DE

Key dates

• Filing date: Dec 12, 1994
• Grant date: Oct 3, 1995
• Expiry date: Dec 12, 2014

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02W30/62
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Caprolactam is obtained from mixtures which contain polymers or thermoplastic molding materials having the repeating unit EQU --N(H)--(CH.sub.2).sub.5 --C(O)-- (a) by cleavage at elevated temperatures in the presence of a base under reduced pressure or (b) in the presence of water, by using a mixture essentially comprising PA1 from 50 to 99.9% by weight of a polymer or of a thermoplastic molding material having the repeating unit EQU --N(H)--(CH.sub.2).sub.5 --C(O)-- PA1 from 0.1 to 50% by weight of additives selected from the group consisting of inorganic fillers, organic and inorganic pigments and dyes, PA1 from 0 to 10% by weight of organic and/or inorganic additives, PA1 from 0 to 40% by weight of non-polyamide-containing polymers and PA1 from 0 to 20% by weight of polyamides, with the exception of polycaprolactam and copolyamides prepared from caprolactam, and carrying out the cleavage in the presence of a base under reduced pressure, the water content of the mixture used being not more than 0.01% by weight, or carrying out the cleavage in the presence of water without the addition of acid or base at from 270.degree. to 350.degree. C. and a weight ratio of water to polymer or …