摘要
大量实验表明,离子液体基于其良好的物理化学性质,可以在温和的条件下有效地将芳香烃从其与脂肪烃的混合物中分离出来,并表现出较高的选择性和溶质分配系数。本文应用密度泛函理论(DFT)探究1-丁基-3-甲基咪唑四氯化铁([BMIM][[FeCl_4])离子液体与正辛烷/对二甲苯分子间的相互作用,同时以[BMIM]Cl离子液体与溶剂相互作用作为对照。从计算结果可以看出,[BMIM][[FeCl_4]和[BMIM]Cl离子液体均能够有效地分离正辛烷和对二甲苯混合物。离子液体阳离子和阴离子之间存在的多重氢键,对离子对、离子液体-溶剂复合物的稳定性起决定性作用。其中,由于咪唑环上C2位置具有较强的路易斯酸性,因此C2-H···Cl具有最强的氢键作用。由于Cl-被[[FeCl_4]^-取代时,电荷被分散,导致[BMIM][[FeCl_4]^-正辛烷/对二甲苯的相互作用弱于[BMIM]Cl-正辛烷/对二甲苯。
It can be found among many reported studies that ILs can effectively separate aromatic compound from aromatic-aliphatic mixtures under mild conditions with higher selectivity and distribution coefficients. The hydrogen bonding behaviors between the ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate（Ⅲ） （[BMIM][FeCl4]） and octane/p-xylene have been investigated with density functional theory （DFT） calculations. The [BMIM]Cl-solutes interactions are also investigated for comparative study. The calculated results show that both [BMIM][FeCl4] and [BMIM]Cl have excellent effect of separating p-xylene with octane, Multiple hydrogen bonds existing between the cation and the anion play the dominant role in determining the stabilization of ion pairs and ion pair-solutes complexes, The hydrogen bond in C2-H…Cl has the strongest interaction due to the strongest acidity of FI atom. The interaction of [BMIM][FeCl4]-octane/p-xylene is weaker than [BMIM]Cl-octane/p-xylene because the charge is dispersed when the Cl- anion is replaced by [FeCl4].
出处
《计算机与应用化学》
CAS
2016年第2期139-146,共8页
Computers and Applied Chemistry
