卤代烃对Ziegler-Natta催化剂催化乙烯聚合的影响

Effects of Halohydrocarbons on Ziegler-Natta Catalyst in Ethylene Polymerization

综述了以卤代烃为促进剂对Ziegler-Natta催化剂催化乙烯聚合的影响。介绍了两种卤代烃的加入方式,分别为在催化剂制备过程中加入和在乙烯聚合过程中加入。在催化剂制备过程中加入卤代烃时,对于不同的催化体系,需根据不同的应用选择不同的卤代烃种类及用量。分析了在乙烯聚合过程中加入卤代烃时,卤代烃种类、卤代烃与钛的摩尔比等因素对催化活性、聚乙烯相对分子质量及其分布、聚合母液中蜡含量和聚乙烯粉料中细粉含量的影响。卤代烃在具体应用时需结合催化剂及聚合工艺的特点进行筛选,以使其适用性达到最佳。

The effects of halohydrocarbons as promoters on ethylene polymerization catalyzed by Ziegler-Natta catalyst were reviewed. Two methods for adding the halohydrocarbons, namely addition in the catalyst preparation and addition in the polymerization, were introduced. For different catalyst systems and different applications, appropriate types and amount of the halohydrocarbons should be chosen. The effects of the halohydrocarbon types and molar ratio of halohydrocarbon to titanium on the catalyst activity in the ethylene polymerization, relative molecular mass of the polyethylene product and its distribution, wax content in the polymerization mother liquid and fine powder content in the polyethylene product were discussed when the halohydrocarbons were added in the course of the ethylene polymerization.