Copolymerization Mechanisms of Propylene and Norbornadiene Catalyzed by Zirconocene Complexes: A Density Functional Theory Study

Bulletin of the Korean Chemical Society

ShuYuan Yu¹ 

[1] Department of Chemistry and Material Science Langfang Teachers University Langfang 065000 China

关键词: Polypropylene functionalization;    Copolymerization;    Chain transfer mechanism;    Metallocene catalysts;    Density functional theory calculations;   

DOI  :  10.1002/bkcs.11399

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

Copolymerization mechanisms of norbornadiene (NBD) and propylene, catalyzed by three zirconocene catalysts (namely, rac‐Me2Si(2‐Me‐4‐Ph‐Ind)2ZrCl2/MAO (catA), rac‐Me2Si(Ind)2ZrCl2/MAO (catB), and rac‐CH2CH2(Ind)2ZrCl2/MAO(catC)), have been studied, using density functional theory computations. It has been found that the barrier (28.5 kcal mol−1) for the insertion of propylene to the [Zr]A‐NBD‐PP1 (the NBD insertion product) is significantly higher than those to [Zr]B‐NBD‐PP1 (22.9 kcal mol−1) and [Zr]C‐NBD‐PP1 (20.5 kcal mol−1), rationalizing the experimental observation that addition of NBD deactivated catA system but only lowered the catalytic activity of catB and catC systems. However, [Zr]A‐NBD‐PP1 can react with H2 easily, which displaces NBD−PP1 chain and gives active [Zr]A−H species to continue copolymerization, which is why the introduction of H2 could recover the catalytic activity of catA system.

【 授权许可】

Unknown