高等学校化学学报Issue(10)：1945-1953,9.DOI:10.7503/cjcu20150327
碱金属阳离子对 Cu+Y 催化甲醇氧化羰基化性能影响的密度泛函理论研究
Density Functional Theory Investigation on the Effect of Alkali Metal Cations on the Catalytic Performance for Cu+Y Zeolites in Oxidative Carbonylation of Methanol†
摘要
Abstract
On the basis of density functional theory, influence of co-cations ( M = Li+, Na+, K+, Rb+ ) adjacenting active center Cu+ on the electronic properties and catalytic activity of Cu+ Y zeolites in oxidative carbonylation of methanol to dimethyl carbonate was investigated. CuMY stable configurations were construc-ted, CO insertion CH3 O species to CH3 OCO was used to evaluate the catalytic activity of CuY zeolites, due to the fact that it was the rate-limiting step of oxidative carbonylation of methanol. The calculation results indicate that Li+, Na+, K+ cations can locate site Ⅰ' in small cages of Y zeolites surrounding the active center Cu+, the adsorption energy of CH3 OH, CO, CH3 O and co-adsorbed CO/ CH3 O on CuMY zeolite increases gradually with increase of cation size, the stability of transition states for CO insert into CH3 O reaction comes to decrease, increases the activation barriers and the corresponding catalytic performance declines. Whereas, Rb+ and Cs+cations located Ⅱ* in the supercage as increase in cation size, decreases activation energy for CO insertion reaction, improves the stability of transition states and the catalytic activity of CuY zeolites. The order of catalytic activity of CuMY zeolites is CuLiY-Ⅰ'>CuCsY-Ⅱ*>CuNaY-Ⅰ'>CuRbY-Ⅱ*>CuKY-Ⅰ'>CuCuY-Ⅰ'. The CuLiY-Ⅰ' catalyst exhibits the best catalytic performance with a lowest rate-limiting reaction activation barrier of 52. 74 kJ/ mol.关键词
碱金属阳离子/密度泛函理论/CuY 分子筛/氧化羰基化/碳酸二甲酯Key words
Alkali metal cation/Density functional theory/CuY zeolite/Oxidative carbonylation/Dimethyl carbonate分类
化学化工引用本文复制引用
张艳青,郑华艳,章日光,李忠,王宝俊,赵秋勇..碱金属阳离子对 Cu+Y 催化甲醇氧化羰基化性能影响的密度泛函理论研究[J].高等学校化学学报,2015,(10):1945-1953,9.基金项目
国家自然科学基金(批准号:21276169)和山西省青年科技研究基金(批准号:2015021030)资助.? Supported by the National Natural Science Foundation of China(No.21276169) and the Natural Science Foundation for Young Scientists of Shanxi Province, China(No.2015021030) （批准号:21276169）
