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Patent Searching and Data


Title:
PROCESS FOR PRODUCING POLYCARBONATE
Document Type and Number:
WIPO Patent Application WO/2000/052077
Kind Code:
A1
Abstract:
A process in which a recovered phenol compound obtained in polycarbonate production with a specific polycondensation catalyst is subjected as a starting material to transesterification and decarbonylation to produce a diaryl carbonate while avoiding various problems caused by impurities, and the diaryl carbonate is subjected to polycondensation to thereby industrially advantageously produce a polycarbonate. The process comprises: a first step in which a diaryl oxalate is synthesized by the transesterification of a dialkyl oxalate with a phenol compound; a second step in which a diaryl carbonate is obtained by the decarbonylation of the diaryl oxalate; a third step in which a polycarbonate is produced by the polycondensation of the diaryl carbonate with a polyhydroxy compound; and a fourth step in which the phenol compound yielded as a by-product in the polycondensation system is separated therefrom and the recovered phenol compound is purified to obtain a purified phenol compound in which the content of the impurities derived from the polycondensation has been reduced. The resultant purified phenol compound is circulated for use in the transesterification as the first step.

Inventors:
NISHIHIRA KEIGO DI
TANAKA SHUJI (JP)
YOSHIDA SHINICHI (JP)
Application Number:
PCT/JP2000/001279
Publication Date:
September 08, 2000
Filing Date:
March 03, 2000
Export Citation:
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Assignee:
UBE INDUSTRIES (JP)
NISHIHIRA TAMIKO HF (JP)
TANAKA SHUJI (JP)
YOSHIDA SHINICHI (JP)
International Classes:
C07C68/00; C08G64/30; (IPC1-7): C08G64/20; C07C68/00; C07C69/96
Foreign References:
EP0832910A21998-04-01
EP0737665A11996-10-16
EP0834495A11998-04-08
EP0834496A11998-04-08
JPH072736A1995-01-06
Other References:
See also references of EP 1081174A4
Attorney, Agent or Firm:
Yanagawa, Yasuo (Yotsuya Shinjuku-ku, Tokyo, JP)
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