铑阳离子配合物催化甲醇羰基化反应的理论计算及设计  

Theoretic Study and Design of Catalysts of Rhodium Cationic Coordination Compound for Carbonylation of Methanol to Acetic Acid

作　　者：王丽琼[1] 李艳萍[2] 

机构地区：[1]宁夏大学宁夏能源化工重点实验室,银川750021 [2]宁夏大学化学化工学院,银川750021

出　　处：《武汉理工大学学报》2013年第2期21-25,共5页Journal of Wuhan University of Technology

基　　金：宁夏自然科学基金资助项目(NZ12137);宁夏大学科学研究基金(ZR1150)

摘　　要：采用自然键轨道理论(NBO)分析了吡啶甲酸铑阳离子催化剂([LRh(CO)2]+,L:吡啶甲酸配体)的结构和成键,结合前期研究工作结论,对催化剂从结构上进行了改进,设计了吡啶乙酸铑阳离子催化剂([LCH2-Rh(CO)2]+,LCH2:吡啶乙酸配体),采用从头算HF方法,在LANL2DZ基组下,优化得到了[LCH2-Rh(CO)2]+催化甲醇羰基化制备乙酸反应的决速步骤(CH3I氧化加成)反应物、产物、中间体、过渡态的构型,对反应每一驻点作了零点能(zero-pointenergy,ZPE)校正,计算了反应位垒(130.02kJ/mol),对比[LRh(CO)2]+催化剂,从构型、电荷分布、前线轨道等方面,探讨了吡啶乙酸铑阳离子催化剂具有高活性的本质原因,结果表明[LCH2-Rh(CO)2]+比[LRh(CO)2]+反应活性更高,共轭结构的破坏和六元环的引入使[LCH2-Rh(CO)2]+能够协同CH3I氧化加成,一定程度上降低了反应位垒。The geometry and bond of pyridine carbonylic acid rhodium cation（[LRh（CO）2]＋ ,L.. pyridine carbonylic acid ligand） have been analyzed for carbonylation of methanol to acetic acid through Nature Bond Orbit（NBO） theory. A- bove previous research, the geometry of [LRh（CO）2 ] ＋ has been improved on and designed in molecule level. Next,densi- ty functional theory （DFT） and ab initio Hartree-Fock （HF） have been performed on rate-determining step of earbonyla- tion of methanol which is catalyzed by [LCH2-Rh（CO） z ] ＋. All structural geometries of reactant, intermediates, transi- tion states and product,respectively, are optimized at in the HF/LANL2DZ level. The energy of station points are im- proved by zero-point-energy（ZPE） correction, and the reaction activation barrier is 87. 92 kJ/mol. Finally, by analyzing molecule obit, Mulliken atom charge and geometry, the substantial reasons of higher activity of [LCH2-Rh（CO）2 ]＋ cata- lyst have been researched. The results indicate that [LCH2-Rh（CO）2 ] ＋ is better catalytic active than [-LRh（CO）2 ] ＋ ,and the breakage of delocalization n bond and the characteristic of the 6-membered ring are reasons in nature.

关 键 词：HF 铑 催化剂 构型 

分 类 号：O643[理学—物理化学]