【摘 要】
：
基于密度泛函理论方法构建并优化了CuMY(M为碱金属阳离子)分子筛的稳定构型,采用速控步骤CO插入CH3O形成CH3OCO反应,研究了碱金属阳离子对Cu+Y分子筛中活性中心周围电子环境
【机 构】
：
太原理工大学煤科学与技术教育部和山西省重点实验室,太原030024;化学化工学院,太原030024太原理工大学煤科学与技术教育部和山西省重点实验室,太原030024化学化工学院,太原030024
【出 处】
：
第八届国际分子模拟与信息技术应用学术会议
论文部分内容阅读
基于密度泛函理论方法构建并优化了CuMY(M为碱金属阳离子)分子筛的稳定构型,采用速控步骤CO插入CH3O形成CH3OCO反应,研究了碱金属阳离子对Cu+Y分子筛中活性中心周围电子环境及催化甲醇氧化羰基化合成碳酸二甲酯性能的影响.计算结果表明,Li+,Na+和K+稳定落位于Y分子筛小笼中,且随着金属离子半径的增大,CH3OH,CO,CH3O在CuMY上的吸附能和CO/CH3O的共吸附能均逐渐增加,CO插入CH3O反应的过渡态结构稳定性逐渐降低,活化能逐渐上升,相应的反应活性逐渐下降.而落位在超笼中Ⅱ*位的Rb+与Cs+则随着离子半径的增大,反应过渡态的结构稳定性提高,克服的活化能降低,反应活性升高.不同CuMY分子筛上催化活性顺序为CuLiY-Ⅰ＞CuCsY-Ⅱ*＞CuNaY-Ⅰ＞CuRbY-Ⅱ*＞CuKY-Ⅰ＞CuCuY-Ⅰ,其中CuLiY-Ⅰ分子筛克服速控反应的活化能垒(52.74kJ/mol)最低.
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