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:
Aug. 19, 2003
Filed:
Oct. 25, 2001
John Patrick Lemmon, Delanson, NY (US);
Ronald James Wroczynski, Schenectady, NY (US);
General Electric Company, Niskayuna, NY (US);
Abstract
The present invention relates to a synthetic method in which one or more diaryl carbonates is reacted with one or more dihydroxy aromatic compounds in the presence of a transesterification catalyst under melt polymerization conditions to afford a product polycarbonate. The transesterifcation catalysts used according to the method of the present invention are alkali metal salts and alkaline earth metal salts of heterocyclic diols in combination with tetraalkylammonium or tetraalkylphosphonium compounds which serve as co-catalysts. The furan diol derivative dimethyl 3,4-dihydroxy-2,5-furandiacarboxylate disodium salt, structure IV, was shown to possess excellent activity as a transesterifcation catalyst for the preparation of polycarbonate under melt polymerization conditions. The catalysts employed according to the method of the present invention provide polycarbonates having substantial molecular weight (M ˜8000-10000 daltons) and reduced levels of Fries rearrangement product relative to conventionally prepared melt polycarbonate having a similar molecular weight.