非均相TiCl4/MgCl2型Ziegler-Natta催化剂催化烯烃配位聚合机理研究进展

Progress on coordination polymerization mechanism of olefins catalyzed by heterogeneous TiCl4/MgCl2 type Ziegler-Natta catalyst

非均相TiCl4/MgCl2型Ziegler-Natta催化剂(负载型Ziegler-Natta催化剂)因其高聚合活性、高立构选择性及低制备成本,是目前聚烯烃领域重要的工业催化剂.本文综述了负载型Ziegler-Natta催化剂催化α-烯烃(乙烯、丙烯)和共轭二烯烃(丁二烯、异戊二烯)配位聚合机理的研究进展,包括TiCl4在MgCl2表面的吸附、钛的烷基化与还原、烷基铝的作用、活性中心数目、活性中心价态、活性中心模型、可能活性中心结构及催化机理、给电子体作用等.最后,展望了负载型Ziegler-Natta催化剂催化烯烃聚合的机遇与挑战.

Heterogeneous TiCl4/MgCl2 type Ziegler-Natta catalysts(supported type Ziegler-Natta catalysts) have been the most important industrial catalysts in polyolefin field due to the high polymerization activity, high stereoselectivity and low preparation cost. This paper reviewed the recent progress on the coordination polymerization mechanism of α-olefins(ethylene, propylene) and conjugated dienes(isoprene, butadiene) including the absorption of TiCl4 on MgCl2 surface, the alkylation and reduction of Ti, the number, valence, structure, model of active centers, the effect of electron donor and alkylaluminum on catalytic mechanism etc. The opportunities and challenges of olefins polymerization catalysed by supported type Ziegler-Natta catalysts were proposed.