BCM催化剂催化乙烯-丙烯共聚行为的研究

Gas-Phase Copolymerization of Propylene/Ethylene Catalyzed by BCM Catalyst

采用BCM催化剂催化乙烯-丙烯气相共聚,研究了不同外给电子体及反应条件对共聚反应速率的影响,引入半衰期概念评价了共聚反应的衰减情况。实验结果表明,通过测定聚合稳定后反应釜内的乙烯与丙烯的摩尔比即可快速判断不同催化体系中乙烯和丙烯聚合速率的差异。外给电子体对r1/r2(r1:乙烯竟聚率;r2:丙烯竟聚率)的影响从大到小的顺序为:四乙氧基硅烷(T-donor)>二异丁基二甲氧基硅烷(B-donor)>二异丙基二甲氧基硅烷(P-donor)>甲基环己基二甲氧基硅烷(C-donor)>二环戊基二甲氧基硅烷(D-donor)。共聚反应衰减速率的大小顺序为:B-donor>T-donor>C-donor>D-donor>Pdonor。采用C-donor时,适宜的反应温度为80℃,随反应压力的增大,乙烯的竟聚率增大。

The gas-phase copolymerization of ethylene and propylene with the BCM catalyst was studied. The effects of different external electron donors and reaction conditions on the copolymerization reaction rate were investigated, and the decay of the copolymerization reaction were evaluated with the half-life（difference between the time when the copolymerization rate reached half of the maximum and the time when the copolymerization rate reached the maximum）. The results indicated that the copolymerization rate with different catalyst systems could quickly be determined by measuring the ratio of ethylene/propylene in the reaction kettle. The sequence of the effects of the electron donors on r1/r2（r1 ： reactivity ratio of ethylene; r2： reactivity ratio of propylene）was： tetraethyl siloxane（T-donor）〉diisobutyl dimethyl silane（B-donor）〉diisopropyl dimethyl silane（P-donor）〉methyl cyclohexyldimethoxysilane（C-donor）〉dicyclopentanyl dimethyl oxygen radical silane（D-donor）. The sequence of the decay rate of the copolymerization with the external electron donors was： B-donor〉T-donor〉C-donor〉D-donor〉P-donor. When C-donor was used, the optimum reaction temperature was 80 ℃.