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    • 8. 发明申请
    • METHOD FOR MAKING POLYCARBONATE
    • 制备聚碳酸酯的方法
    • WO2003014188A1
    • 2003-02-20
    • PCT/US2002/023175
    • 2002-07-19
    • GENERAL ELECTRIC COMPANY
    • MCCLOSKEY, Patrick, JosephNISOLI, AlbertoREILLY, Warren, William
    • C08G64/30
    • C08G64/307
    • Polycarbonates having a high level of endcapping and containing a low level of Fries rearrangement product are prepared from dihydroxy aromatic compounds, such as bisphenol A, and diaryl carbonates such as diphenyl carbonate in a two stage process involving a tetraalkyl phosphonium carboxylate catalyzed oligomerization of the reactants in a first reaction stage followed by the addition of an alkali metal hydroxide co-catalyst in the second stage of the polymerization reaction. The late addition of the co-catalyst provides improved polymerization reaction rates as judged by higher polycarbonate molecular weights. The amount of alkali metal hydroxide co-catalyst is small thus avoiding the formation of excessive amounts of Fries product. The method has been used to provide Fries product levels between 200 and 1000 parts per million in polycarbonates having M n values of at least 7,500 Daltons.
    • 具有高水平的封端并含有低含量的Fries重排产物的聚碳酸酯由二羟基芳族化合物如双酚A和碳酸二芳基酯如碳酸二苯酯在涉及四烷基鏻羧酸酯催化的反应物低聚的两步法中制备 在第一反应阶段,然后在聚合反应的第二阶段加入碱金属氢氧化物助催化剂。 通过较高的聚碳酸酯分子量判断,辅助催化剂的晚期添加提供了改进的聚合反应速率。 碱金属氢氧化物助催化剂的量很小,从而避免形成过量的油炸产品。 该方法已被用于在具有至少7,500道尔顿Mn值的聚碳酸酯中提供200至1000ppm之间的Fries产品水平。