甲醇羰基化制乙酸反应催化剂的分子设计
Molecular Designing of the Catalyst for Carbonylation of Methanol to Acetic Acid
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摘要: 采用HF从头算,有效核势能近似(ECP)方法,在LANL2DZ赝势基组水平下,研究了铑配合物系列催化剂,以及其同系物、同分异构体的几何结构和能量;同时,利用AIM2000电子密度拓扑软件,对每种配合物的中心Rh原子电子密度和主要原子间键鞍点电子密度的Laplacian量▽2ρ(r)进行了分析比较.研究结果表明,邻-乙酸-吡啶铑阳离子催化剂的Rh-O间共价作用最弱,并且由于其具有的不对称螯合物结构,使得Rh-O键易于断开,对于催化反应的决速步骤来说,该催化剂是最有利于降低活化能的Abstract: Pyridine carbonylic acid Rh catalyst(［MRh(CO)2+, M: pyridine carbonylic acid complexes) and its homolog, isomer were studied by using the ab initio method with the effective core potential(ECP) approximation in HF/LANL2DZ level. From the view of topological analysis of the electronic density, electronic density and Laplacian of all catalysts’ critical points were studied. The results indicated that the center metal (Rh) of ［MRh(CO)2+ catalyst and its homolog and isomer haven’t more effective charge when they employed asymmetric chelate ligand. The o-acetic aci-pyridine-Rh catalyst has the lowest reaction energy barrier and the weakest Rh-O covalence orbitals interreaction which tends to break.
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