Depelopment of supported catalysts for living polymerization of olefins and its application to gas-phse polymerization

因此，活性聚合引起了人们的广泛关注，已有多篇文献报道了丙烯均相催化活性聚合。然而，有几个例子，丙烯的活性聚合的负载单中心催化体系，这应该是非常重要的，从实用的角度来看。我们以前发现，在庚烷中，在0℃下，用易溶于烃类的无三烷基铝的改性甲基铝氧烷（dMMAO）活化的螯合（二酰胺）二甲基钛配合物（1）可以进行丙烯的活性聚合。氧化铝和氧化镁的载体和dMMAO在庚烷中的反应，并与1进行丙烯聚合，以澄清负载效果干燥的MMAO。对于干燥的MMAO，无论金属氧化物如何，负载体系在0℃下都能进行丙烯的活性聚合，没有任何诱导期。这些体系的增长速率常数（k_p）和聚合物的分子量分布（M_w/M_n）取决于所用的金属氧化物。Kp值随载体上MMAO的刘易斯酸性的增加而增大，而Mw/Mn的展宽则归因于载体上催化剂的非均匀性引起的刘易斯酸性的分布。我们还用柄型芴基氨基二甲基钛（2）代替1进行丙烯聚合，当用dMMAO活化时，柄型芴基氨基二甲基钛（2）进行丙烯的活性聚合。虽然硅胶和氧化铝的2-负载dMMAO体系表现出非常高的初始活性，但体系失活并且也发生链转移。结果表明，配合物与负载型催化剂的结合对负载型催化体系的活性聚合是非常重要的。

The living polymerization, therefore, has attracted much attention and several papers have reported on the living polymerization of propene by homogeneous catalytic systems. There are, however, few examples for living polymerization of propene by supported single-site catalytic systems, which should be very important from the practical point of view. We have previously found that living polymerization of propene proceeded in heptane at 0℃ by a chelating (diamide) dimethyltitaniumcomplex (1) activated with trialkylaluminum-free modified methylaluminoxane (dMMAO), which is easily soluble in hydrocarbons.We prepared supported dMMAOs using silica gel, alumina and magnesia by the reaction of the support and dMMAO in heptane and conducted propene polymerization with 1 to clarify the supporting effects of dried MMAO. The supported systems conducted living polymerization of propene at 0℃ without any induction period regardless of the metal oxides for dried MMAO. The propagation rate constants (k_p) of these systems and the molecular weight distribution (M_w/M_n) of the produced polymer depended on the metal oxide employed. The k_p value increased with the increase in Lewis acidity of MMAO on the support and the broadening (M_w/M_n) was ascribed to the distribution of Lewis acidity caused by the heterogeneity of the supported cocatalyst. The systems gave atactic polypropylene regardless of the metal oxides for dried MMAO.We also conducted propene polymerization with ansa-fluorenylamidodimethyltitanium (2), which conducts living polymerization of propene when activated with dMMAO, in place of 1. Although the 2-supported dMMAO systems of silica-gel and alumina showed very high initial activity, the system deactivated and chain transfer also occurred. The results indicated that the combination of the complex and the supported activator was very important for the living polymerization with supported catalytic systems.