Bayer Aktiengesellschaft

Andreas Chrisochoou

Johan Vanden Eynde

Kaspar Hallenberger

Steffen K&uuml;hling

Dieter Heinz

Nikolaus Janke

Werner B&auml;cker

Reinhard Pech

A two stage interfacial polycondensation process for the production of carbonic acid diaryl ester is disclosed. The invention concerns an improvement to the process that entails forming in a first stage a reaction mixture that contains an inert solvent, at least one monophenol, phosgene, and aqueous alkali hydroxide solution, passing said reaction mixture to a second stage through at least one constriction at a velocity of 3 to 15 m/s under conditions designed to expose the mixture to a pressure drop of 0.1 to 2.5 bar, and in said second stage passing said mixture through at least one dispersing element at a velocity of 2 to 10 m/s under conditions designed to expose the mixture to a pressure drop of 0.1 to 0.5 bar. The resulting product is characterized by its purity and suitability for the manufacture of polycarbonates in the melt transesterification process.

Continuous process for producing carbonic acid diaryl ester

The present invention relates to a process for preparing phosphoric acid esters, in particular monomeric bisaryl diphosphates, or bridged phosphates.

Process for preparing phosphoric acid esters

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Kö'ln, Germany

Andreas Chrisochoou