Process for the production of polycarbonate

US5258484A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Reinhard Schomacker · Leverkusen, DE
• Uwe Hucks · Alpen, DE
• Gunther Weymans · Leverkusen, DE
• Wolfgang Herrig · Bensberg, DE
• Jurgen Kirsch · Cologne, DE

Key dates

• Filing date: Jun 19, 1992
• Grant date: Nov 2, 1993
• Expiry date: Jun 19, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G64/24
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for the continuous production of a thermoplastic aromatic polycarbonate is disclosed. Accordingly, in a reactor system which includes a tube reactor and a tank equipped with a stirrer, there are reacted a preheated dialkali diphenolate aqueous solution with gaseous phosgene in CH.sub.2 Cl.sub.2 and/or in chlorobenzene solution containing excess phosgene, in a mixer to form a mixed emulsion. The emulsion is then transported at least partly against the force of gravity into the tube reactor to facilitate a polycondensation reaction and in which after a residence time of at least 10 seconds and without dissipation of the heat of reaction there is added a chain terminator. The heat of reaction is dissipated in said tank and aqueous sodium hydroxide and catalyst are added to complete the reaction. The process according to the invention leads to high yields of phosgene.