Phase boundary processes for preparing polycarbonates

US7847051B2 · kind B2 · utility

Assignee

• Bayer MaterialScience AG · DE

Inventors

• Wolfgang Ebert · Krefeld, DE
• Christian Kords · Krefeld, DE
• Rolf Bachmann · Busswil, CH
• Lars Obendorf
• Johan Vanden Eynde · Zwijnaarde, BE
• Bert Ruytinx · Halen, BE
• Johann Seeba · Leverkusen, DE

Key dates

• Filing date: Mar 5, 2009
• Grant date: Dec 7, 2010
• Expiry date: Mar 5, 2029

Classification

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

Abstract

Continuous processes for preparing polycarbonates having a weight average molecular weight Mw, of 15,000 to 200,000 g/mol, the processes comprising reacting a dihydroxydiarylalkane and phosgene in the presence of a catalyst in a phase boundary process comprising: continuously dispersing in a disperser an organic phase comprising at least a portion of the phosgene and a solvent suitable for the polycarbonate and an aqueous phase comprising the dihydroxydiarylalkane, water and an alkali solution present in an amount of 1.5 to 2.5 moles per mole of the dihydroxydiarylalkane, to form a mixture; reacting the mixture in a first reactor with a residence time of less than 0.5 seconds; further reacting the mixture in a second reactor with addition of further alkali solution and, optionally, a chain terminator; and effecting further condensation in a third reactor with addition of further alkali solution and, optionally, a chain terminator, in the presence of the catalyst.