甲醇氧化羰基化反应中CO和CH_3O在CuCl(111)表面上吸附作用的理论研究

Theoretical Studies on the Interaction of CO and CH_3O on CuCl( 111)Surface for Methanol Oxidative Carbonylation

基于密度泛函理论方法,采用广义梯度近似方法结合周期平板模型,对甲醇氧化羰基化反应中CuCl(111)表面上CO和CH3O的吸附、共吸附及CH3OCO的吸附进行了系统研究,探讨了CO和CH3O反应生成CH3OCO以及CH3OCO和CH3O反应生成碳酸二甲酯(DMC)的动力学特性.计算结果表明,在CuCl(111)表面的共吸附体系中,CO和CH3O之间的相互作用力比自由态的CO和CH3O之间的作用力大;CO和CH3O反应生成CH3OCO为整个甲醇氧化羰基化反应的速控步骤,活化能为113.19 kJ/mol,计算结果与实验结果一致.

Based on density functional theory method in the generalized gradient approximation, together with the periodic slab model, the single adsorption of CO and CH3 O, as well as the co-adsorption of CO and CH3 O on CuCl（111） surface involving in methanol oxidative carbonylation to dimethyl carbonate（ DMC） were sys-tematically investigated. The reaction mechanisms of CO interaction with CH3 O leading to CH3 OCO and CH3OCO interaction with CH3O to DMC on CuCl（111） surface were discussed. The calculated results indi-cate that the interaction between CO and CH3 O in the co-adsorption system is stronger than that between free CO and CH3 O in gas phase, CO insertion into adsorbed CH3 O on CuCl（111） surface to CH3 OCO species are the rate-limiting step for the oxidative carbonylation of methanol to DMC, and the corresponding activation bar-rier is 113. 19 kJ/mol, the calculated results are in accordance with the reported experimental facts.