【摘要】 用密度泛函理论(DFT)在B3LYP/6鄄31G(d,p)的计算水平上研究了离子液中1鄄乙基鄄3鄄甲基咪唑阳离子(EMIM+)的4鄄H和5鄄H原子催化丁烯双键异构反应的可能途径,优化了反应体系的平衡态和过渡态的几何构型,分析了反应过程中键参数的变化,通过振动分析对平衡态和过渡态进行了验证.计算结果表明,离子液中的EMIM+首先通过4鄄H和5鄄H原子吸附丁烯,进而催化丁烯的双键异构反应,EMIM+的4鄄H和5鄄H催化1鄄丁烯异构为2鄄丁烯的正反应活化能分别为204.2和207.3kJ·mol-1,逆反应活化能约为220.9和223.8kJ·mol-1,反应为基元反应.更多还原

【Abstract】 The possible reaction paths of butene isomerization catalyzed by 4-H and 5-H of 1-ethyl-3-methyl-imidazolium (EMIM+) have been studied by using density functional theory (DFT) at B3LYP/6-31G** levels. The geometries of the reactants, transition states and products are fully optimized by energy gradient technology and the equilibrium states and transition states are verified according to the number of imaginary frequency obtained through vibrational analysis. The computed results indicate that the butene molecule approaches to 4-H or 5-H of EMIM+ at the first and then forms a supermolecule due to physical adsorption. Whereafter the isomerization of butene double bond is catalytically performed. The forward energy barriers of the rearrangement reaction catalyzedby 4-H and 5-H atom of EMIM+ are 204.2 and 207.3 kJ·mol-1, and the reverse energy barriers are 220.9 and 223.8 kJ·mol-1, respectively. The isomerization of butene catalyzed by the proton of the imidazolium ring may proceed through multi-channel at one-step process.更多还原