【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
【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.
其他文献
Prediction of the birefringence values of borate is very essential for developing new optical materials in UV range.In this paper,the birefringence values o
The development of frequency-conversion technology in the infrared region is in urgent need of new excellent infrared nonlinear optical(IR NLO)materials.How
The impurity effects of the transverse Ising spin model with a magnetic impurity are investigated via the correlation function and entanglement on the basis
Design and fabrication of functional carbon nanostructures is a challenging but meaningful mission for scientists to propel the development of nanotechnolog
The first mixed-anion transition metal(TM)fluoride with [MF6]x-(M = TM cation)anion group,Na3NH4(TiF6)(SO4)·H2O(NTS),was synthesized by a facile hydrotherm
A series of LiSr1-xPbxBO3(x = 0.138,0.285,0.320,0.379,0.417,0.5)crystals have been obtained by a high-temperature solution reaction with spontaneous nucleat
BRAF is a key intracellular cascade involved in the regulation of cellular proliferation,survival and differentiation.BRAF is easily activated by RAS and ha
A new family of noncentrosymmetric isostructural compounds,Na2Hg3M2S8(M = Si,Ge,and Sn),was successfully synthesized.They crystallize in the tetragonal spac
With the introduction of an alkali metal into the B- O framework,two new alkali metal borate crystals,Li5Cs2B7O14 and Li4CsB5O10,have been obtained for the
The single crystals of a new compound Pb2Ba3(BO3)3Br has been grown by the spontaneous crystallization method.It crystallizes in the noncentrosymmetric orth