【摘要】 本文测定丁二烯在La、Nd、Sm、Gd、Dy、Ho和Y七种稀土氯化物与两种烷基铝分别所组成的催化剂之烷基铝链转移速度常数k_a,结果表明,不同稀土催化剂k_a的变化趋势与链增长速度常数相似。动力学方法证明钐催化剂失活按双基终止进行。本文对稀土催化剂失活机理作了初步探讨。更多还原

【Abstract】 The rate constants of chain transfer in the polymerization of butadiene with LnCl3-C2H5OH-AlR3 catalysts (Ln=La, Nd, Sm, Gd, Dy, Ho or Y; AlR3 =AT(C2H5)3 or Al(i-C4H9)3) Were evaluated. Analogous to the propagation rate constants described in the early paper these rate constants varies also with the rare earth element used in the catalysts and decreases in the same order. The kinetic study showed that the deactivation of active center initiated with Sm-catalyst was second order. Besides, the mechanism of deaetivation of active center has been proposed for the present polymerization system.更多还原