The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 24, 2001
Filed:
Aug. 20, 1999
Raghunath Vitthal Chaudhari, Pune, IN;
Ashutosh Anant Kelkar, Schenectady, NY (US);
Sunil Purushottam Gupte, Pune, IN;
Bhalchandra Mahadeo Bhanage, Pune, IN;
Mohammed Shadbar Qureshi, Pune, IN;
Bahram Moasser, Schenectady, NY (US);
Eric James Pressman, East Greenbush, NY (US);
Swaminathan Sivaram, Pune, IN;
Chilukuri Ver Avadhani, Pune, IN;
Subbareddiar Kanagasabapathy, Pune, IN;
General Electric Company, Schenectady, NY (US);
Abstract
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.