Process for cleaving polycarbonates into bisphenols and diaryl carbonates

US5391802A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Hans-Josef Buysch · Krefeld, DE
• Norbert Schon · Krefeld, DE
• Steffen Kuhling · Meerbusch, DE

Key dates

• Filing date: Jun 14, 1993
• Grant date: Feb 21, 1995
• Expiry date: Jun 14, 2013

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C68/06
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process is disclosed for cleaving polycarbonates into bisphenols and diaryl carbonates by transesterifying with phenols in the presence of catalysts. The process entails isolating bisphenols from the product of the transesterification, and subjecting the remaining mixture which contains phenols and diaryl carbonates to flash distillation. The phenols and diaryl carbonates are distilled off and separated, and the diaryl carbonates are recovered.