| 摘要 |
Provided are a method for producing polycarbonates through melt transesterification, wherein is used a polymerization catalyst comprising a phosphorus-containing basic compound and a quaternary phosphonium salt having a specific structure; and a method for producing polycarbonates, which comprises pre-polymerization to prepare polycarbonate prepolymers followed by final polymerization of said prepolymers in a solid phase or in a swollen solid phase to produce the products, polycarbonates, and in which (1) a catalyst comprising a phosphorus-containing basic compound and a quaternary phosphonium salt having a specific structure is used in the pre-polymerization and in the final polymerization, or (2) a catalyst of a tri-valent or penta-valent phosphorus compound or a nitrogen-containing organic basic compound is used in the final polymerization, or (3) the final polymerization is effected in a vapor-phase atmosphere having an oxygen concentration of not larger than 2 ppm. In those methods, high-quality polycarbonates having good appearance, high heat resistance and high hydrolysis resistance are produced extremely efficiently.
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