八角石
环加成
沸石
化学
催化作用
吸附
乙烯
密度泛函理论
环氧化物
二价
环氧乙烷
无机化学
过渡金属
活化能
戒指(化学)
金属
物理化学
计算化学
有机化学
聚合物
共聚物
作者
Winyoo Sangthong,Jakkapan Sirijaraensre
标识
DOI:10.1016/j.jmgm.2022.108321
摘要
Epoxide ring opening and cycloaddition with CO2 is one of the promising routes to convert CO2 to more valuable industrial chemicals. In this work, density functional theory calculations with the M06-L/6-31G(d,p) level of theory have been employed to study the cycloaddition of ethylene oxide (EO) with CO2 over M(II)-faujasite zeolite (M = Ni, Cu, and Zn) in the absence of a co-catalyst. The influence of the exchanged metals strongly dominates the adsorption of EO. The binding energies of EO on the active site are -39.9 (Ni-FAU), -24.2 (Cu-FAU), and -35.0 (Zn-FAU) kcal/mol, respectively. The reaction mechanism is proposed to occur via the concerted mechanism, in which the metals initiate the EO ring opening and the formation of two new C-O bonds between the adsorbed EO and CO2 proceed in a single step. The activation energy of the reaction catalyzed by Cu-FAU is 24.2 kcal/mol whereas that of Ni and Zn-FAU is found to be 31.1 and 31.4 kcal/mol, respectively. Moderate adsorption of EO and a larger electron transfer at the transition state are the important keys that reduce the activation energy for the Cu-FAU lower than in the other systems.
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