Ziegler–Natta (ZN) catalysts recognized as mainstream and efficient polymerization reaction catalysts are widely used for the polymerization of monolefins and diolefins due to their excellent properties. The addition of electron donors to the catalyst can effectively improve its regularity. In this article, the chelate coordination of the internal electron donors 2,3-dimethyl diethylsuccinate (DES), 2,3-diisopropyl diethylsuccinate (DIS), 2,2-dimethyl-1,3-dimethoxypropane (DMMP), and 2,2-diisopropyl-1,3-dimethoxypropane (DIMP) on the catalyst support was investigated by the density functional theory (DFT). By calculating the activation energy of the reaction before and after the addition of the internal electron donor, the effect of the internal electron donor on the stereoselectivity of the polymerization reaction was analyzed. The results indicate that all four internal electron donors can be stably adsorbed onto the support, forming closer interactions with adjacent active centers. In the butadiene insertion process, the si configuration is more favorable than the re configuration. With the addition of DES, DIS, DMMP, and DIMP, the stereoselectivity of the polymerization reaction increased from 0.7 kcal/mol on the bare active center model to 0.9, 1.2, 0.8, and 1.5 kcal/mol, respectively. Particularly noteworthy is the fact that the addition of DIMP showed the most pronounced improvement in reaction stereoselectivity.

中文翻译：

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内部电子供体对TiCl4/MgCl2 Ziegler-Natta催化剂催化的丁二烯聚合的影响


齐格勒-纳塔 （ZN） 催化剂是公认的主流高效聚合反应催化剂，由于其优异的性能，被广泛用于单烯烃和二烯烃的聚合。在催化剂中加入电子供体可以有效提高其规则性。本文采用密度泛函理论 （DFT） 研究了内部电子供体 2,3-二甲基二乙基琥珀酸酯 （DES）、2,3-二异丙基二乙基琥珀酸酯 （DIS）、2,2-二甲基-1,3-二甲氧基丙烷 （DMMP） 和 2,2-二异丙基-1,3-二甲氧基丙烷 （DIMP） 在催化剂载体上的螯合配位。通过计算添加内电子供体前后反应的活化能，分析了内电子供体对聚合反应立体选择性的影响。结果表明，所有四个内部电子供体都可以稳定吸附到载体上，与相邻的活性中心形成更紧密的相互作用。在丁二烯插入过程中，si 构型比 re 构型更有利。随着 DES、DIS、DMMP 和 DIMP 的加入，聚合反应的立体选择性从裸活性中心模型的 0.7 kcal/mol 分别增加到 0.9、1.2、0.8 和 1.5 kcal/mol。特别值得注意的是，添加 DIMP 显示出反应立体选择性的最显着改善。