新型非对称二醚给电子体丙烯聚合催化剂研究

1，3－丙二醚类化合物为给电子体合成的新一类复相Ziegler－Natta催化剂（Z-N催化剂），其用于丙烯聚合时，在无需外加给电子体的情况下，可得到高活性的催化剂和高等规度的聚丙烯，催化剂的活性是以邻苯二甲酸二丁酯为内给电子体合成的Z-N催化剂的2～3倍，且得到聚丙烯的等规度大于95％1-4]．由于1，3－丙二醚类化合物与载体的配位作用较强，不易与AlR3反应，因此在丙烯聚合时无需外给电子体，并能降低反应体系的复杂性，有利于研究活性中心结构和聚合机理［5-7]．以往研究均采用对称结构的 1，3－丙二醚类化合物作内给电子体［2-7]，其结构如 Scheme 1 所示．本文采用一种新的

Studies on Catalyst Containing Novel Asymmetric Diether for Propene Polymerization

Abstract MgCl2 supported Ziegler-Natta catalyst containing a novel asymmetric diether as internal donor was prepared for polymerization of propene. The effects of polymerization temperature and the n(Al)/ n(Ti) ratio on the catalytic activity and the molecular weight, the isotacticity and the melting point of polypropene were investigated. In comparison with the symmetric diether catalysts, the catalytic activity and the isotacticity of polypropene were much lower. The stereosequence distributions were analyzed by means of 13C NMR and the results obtained indicate that isotactic, syndiotactic and iso-syndiotactic block polypropenes were produced. The stereo effect of MBF and the polymerization mechanism were discussed.