Process for the preparation of polycarbonate

US8173762B2 · kind B2 · utility

Assignee

• Bayer MaterialScience AG · DE

Inventors

• Pieter Ooms · Krefeld, DE
• Andreas Bulan · Langenfeld, DE
• Johann Rechner · Krefeld, DE
• Rainer Weber · Leverkusen, DE
• Marc Buts · Duffel, BE
• Johan Vanden Eynde · Zwijnaarde, BE

Key dates

• Filing date: Jul 2, 2010
• Grant date: May 8, 2012
• Expiry date: Aug 3, 2030

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C68/02
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A combined process for the preparation of polycarbonate from bisphenols and diaryl carbonates, the monophenol liberated being reacted again for the preparation of the diaryl carbonate and the alkali metal halide forming in the preparation of the diaryl carbonate being converted by electrochemical oxidation, optionally over a gas diffusion electrode, into chlorine and alkali hydroxide solution, the chlorine being recycled into the preparation of the phosgene and the alkali hydroxide solution being recycled into the preparation of the diaryl carbonate.