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US 6,747,118 B2Granted
Storage of phosphonium phenolate catalysts and their use as interesterification catalysts
AssigneeBayer Aktiengesellschaft
InventorsMelanie Moethrath, Uwe Hucks, Silke Kratschmer, Johann Rechner
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Abstract
A process for preparing a melt transesterification catalyst is disclosed. The process entails (i) obtaining a phenol adduct of phosphonium phenolatein the form of crystalline solid and (ii) storing the solid phenol adductin a closed container at relative humidity of 30 to 70 % and at temperature of −30 to 50° C. The thus prepared catalyst is suitable in the production of polycarbonate in the melt transesterification process.
Claims4
A process for preparing a melt transesterification catalyst comprising:
- (i) obtaining a phenol adduct of phosphonium phenolate in the form of a crystalline solid and
- (ii) storing said solid in a closed container that includes a polyethylene liner, the container being sealed under nitrogen atmosphere, the containers thereafter being stored at a relative humidity of 30 to 70% and at a temperature of −30 to 50° C.,
- said melt transesterification being suitable for use in a process for the production of polycarbonate.
Dependencies are inferred from the claim text.