General Electric Company

Subbareddiar Kanagasabapathy

Raghunath Vitthal Chaudhari

Ashutosh Anant Kelkar

Sunil Purushottam Gupte

Eric James Pressman

Swaminathan Sivaram

Bahram Moasser

Chilukuri Ver Avadhani

Bhalchandra Mahadeo Bhanage

Mohammed Shadbar Qureshi

Subramaniam Radhakrishnan

Polycarbonate oligomers are prepared by oxidative carbonylation of a dihydroxyaromatic compound such as bisphenol A in the presence of a catalyst comprising a Group VIII metal such as palladium, an inorganic and/or an organic co-catalyst, a halide source and an alcohol-free solvent comprising at least one liquid aromatic hydrocarbon, optionally in combination with a dipolar aprotic liquid such as N-methylpyrrolidinone. These oligomers may be further polymerized by melt polymerization to precursor polycarbonate oligomers which may be converted to high molecular weight polycarbonates by melt or solid state polymerization.

Method for preparing polycarbonates by oxidative carbonylation

Diaryl carbonates such as diphenyl carbonate are prepared by reaction of hydroxyaromatic compounds such as phenol with oxygen and carbon monoxide in the presence of a catalyst composition comprising a Group VIIIB metal such as palladium or a compound thereof, a bromide source such as a quaternary ammonium or hexaalkylguanidinium bromide and a polyaniline in partially oxidized and partially reduced form. The polyaniline is preferably halide-doped and in the form of a blend with a binder polymer containing ether or ester groups and a complex-forming salt.

Method for preparing diaryl carbonates with improved selectivity

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Pune, India

Subbareddiar Kanagasabapathy