VERFAHREN ZUR HERSTELLUNG VON POLYCARBONAT

• Main Authors: TANAKA, SHUJI, NISHIHIRA, KEIGO, YOSHIDA, SHINICHI
• Format: Patent
• Language: German
• Published: 15.05.2005
• Edition: 7
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; COMPOSITIONS BASED THEREON; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; METALLURGY; ORGANIC CHEMISTRY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

A process for preparing polycarbonate is composed of the steps of transesterifying a dialkyl oxalate and a phenolic compound to give a diaryl oxalate; decarbonylating the diaryl oxalate to give a diaryl carbonate; reacting the diaryl carbonate with a polyvalent hydroxyl compound in the presence of a catalyst containing an amine compound or an ammonium compound to give the polycarbonate, removing a phenolic by-product/amine by-product mixture; collecting the mixture; purifying the mixture so that the amount of the amine by-product in the mixture is reduced to give a phenolic by-product mixture not containing the amine by-product in an amount of more than 600 ppm; and, utilizing thus purified phenolic mixture as a whole or a part of the phenolic compound in the first step.