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    • 14. 发明专利
    • PRODUCTION OF POLYCARBONATE
    • JPH0687954A
    • 1994-03-29
    • JP12568291
    • 1991-03-07
    • DAICEL CHEM
    • OSHINO YASUHIROSUGANO TATSUYA
    • C08G64/30C08G64/20
    • PURPOSE:To obtain a polycarbonate polymer having a high mol.wt. without employing toxic phosgene by melt-polycondensing a dihydric phenol with a carbonic diester in the presence of a catalyst such as a basic nitrogen compound and a catalyst such as (substituted)phenylacetic acid. CONSTITUTION:A dihydric phenol [e.g. 2,2-bis(4-hydroxyphenyl)propane] and a carbonic diester (e.g. diphenyl carbonate) are subjected to a melt- polycondensation reaction in the presence of a catalyst such as a nitrogen compound (e.g. 2-methylimidazole) and a catalyst such as a non-substituted or substituted phenylacetic acid of the formula (R1 is H, 1-5C alkoxy, nitro; R2, R3 are H, 1-5C alkyl, phenyl) (e.g. phenylacetic acid) to produce the objective high mol.wt. polycarbonate without using toxic phosgene, the melt- polycondensation reaction comprising stirring the raw materials at 180 deg.C in a nitrogen atmosphere for 1hr, subjecting the reaction product to the rise in temperature, while gradually lowering the pressure, and finally polycondensing the reaction product at 270 deg.C under 0.1Torr for 1hr, while distilling off the by-produced phenol.