丙烯聚合用Ziegler-Natta催化剂的内给电子体研究进展

Research progress of internal donor in Ziegler-Natta catalyst for propylene polymerization

综述了丙烯聚合用Ziegler-Natta(Z-N)催化剂中内给电子体的研究进展,并对各类内给电子体的应用实例进行了评价。其中,以1,3-二醚、琥珀酸酯和1,3-二醇酯类化合物为内给电子体制备的Z-N催化剂具有活性高、立体定向性高,用该催化剂制备的聚丙烯具有特征相对分子质量分布等特点。分析具有代表性的内给电子体所制催化剂的活性中心模型发现,单酯体系的等规和无规活性中心在Lewis酸作用下存在可逆平衡,二醚体系中醚氧原子电子云的转移和二醚的空间结构影响钛活性中心的性能。

The authors summarized the research progress of internal electron donors（IDs） in Ziegler-Natta（Z-N） catalysts for propylene polymerization and evaluated the applications of the catalysts with different IDs. The Z-N catalysts with 1,3-diethers, succinates and 1,3-diol diesters compounds as IDs have high activity and stereospecificity. The resultant polypropylene has characteristic relative molecular mass distribution. Moreover, it is found by analyzing the active center models of the catalysts prepared with representative IDs that the isotactic and atactic active centers in monoester system under the influence of Lewis acid exist dynamic equilibrium, and the performance of Ti active centers in diether catalyst system is affected by the transfer of electron cloud from oxygen atoms of diether to Ti active centers and the spatial structure of diether.