国产第四代Ziegler-Natta催化剂氢调敏感性的第一性原理计算

摘要/Abstract

摘要： 基于密度泛函理论（DFT），建立了Ziegler-Natta催化剂分子模型，模拟计算了催化剂表面的吸附情况和吸附机理，分析了影响催化剂氢调敏感性的吸附位点和优势内给电子体。结果表明：在完整的MgCl₂ 表面上Mg原子主要为五配位形式，没有多余的活性位点，不利于TiCl₄的化学吸附；TiCl₄在氯化镁β晶型(110)表面和β晶型(100)表面上的单氯原子缺陷处都存在化学吸附，前者的吸附能普遍比后者的高，电荷转移量更多，吸附更加稳定。对于β晶型(100)表面双氯原子缺陷虽然可以提供更多的活性吸附位点，但是表面对TiC1₄的吸附能力并没随之增加，TiC1₄在(100)表面更倾向于在单氯原子表面缺陷结构中吸附，形成双氯桥。在β晶型(110)表面，双氯原子缺陷的构型更有利于TiC1₄吸附，Ti-Cl键中的2个Cl原子被吸附在缺陷表面中的双Cl原子缺陷位置上，并与相邻的Mg原子形成新的Mg-Cl键，从而形成活性中心。内给电子体的计算结果表明，邻苯二甲酸二异丁酯在两个表面的吸附能均高于苯甲酸乙酯，更适合作为催化剂的内给电子体。

关键词: Ziegler-Natta催化剂, 氢调敏感性, 第一性原理, 表面吸附

Abstract: Based on the Density Fundtional Theory(DFT),a Ziegler-Natta catalyst molecular model was established,the adsorption on the catalyst surface was calculated, and the adsorption sites and dominant internal electron donors were studied that can improve the hydrogen modulation sensitivity of the catalyst by simulating the adsorption mechanism. The results show that the Mg atom on the complete MgCl₂ crystal plane is mainly composed of 5 coordinations, without redundant active sites, which is not conducive to the chemical adsorption of TiCl₄. TiCl₄ has chemical adsorption at the single atomic defects on the β crystal (110) crystal plane and the β crystal (100) crystal plane. Among them, the adsorption energy at the single atomic defects on the β crystal (110) surface is generally higher than that at the atomic defects on the β crystal (100) surface, with more charge transfer and more stable adsorption. Although the diatomic defects on the β-crystalline (100) surface can provide more active adsorption sites, the adsorption capacity of the surface for TiC1₄ does not increase accordingly. TiC1₄ is more inclined to adsorb in the single-atom surface defect structure on the (100) surface to form a dichloro bridge. On the β-crystalline (110) surface, the configuration of diatomic defects is more conducive to the adsorption of TiC1₄. The Cl atom in the Ti-Cl bond replaces the Cl atom position in the original complete surface to form a new Mg-Cl bond with the Mg atom, thereby forming an active center. The calculation results of the internal electron donor show that the adsorption energy of diisobutyl phthalate on both surfaces is higher than that of ethyl benzoate, making it more suitable as an internal electron donor for the catalyst.

Key words: Ziegler-Natta catalyst, hydrogen sensitivity, first principles, surface adsorption

张亚卓. 国产第四代Ziegler-Natta催化剂氢调敏感性的第一性原理计算[J]. 石油炼制与化工, 2025, 56(4): 132-139.

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