Understanding the interactions between tris(pentafluoroethyl)-trifluorophosphate-based ionic liquid and small molecules from molecular dynamics simulation  

作　　者：ZHANG XiaoChun LIU ZhiPing LIU XiaoMin 

机构地区：[1]Beijing Key Laboratory of Ionic Liquids Clean Process,Key Laboratory of Green Process and Engineering,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China [2]Division of Molecular and Materials Simulation,State Key Laboratory of Organic-lnorganic Composites,Beijing University of Chemical Technology,Beijing 100029,China

出　　处：《Science China Chemistry》2012年第8期1557-1565,共9页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China (21106146, 20976004, 20903098 and 21073194)

摘　　要：Tris(pentafluoroethyl)trifluorophosphate ([FEP])-based ionic liquids have been widely applied in many fields. For better understanding the properties of [FEP]-based ionic liquids, the interactions between 1-hexyl-3-methylimidazolium ([hmim])[FEP] and small molecules were investigated by molecular dynamics simulations in this work. The small molecules are water, methanol and dimethyl ether. The united-atom (UA) force fields were proposed for methanol and dimethyl ether based on AMBER force field. The densities, enthalpies of vaporization, excess molar properties, and diffusion coefficients of the mixtures were calculated, as well as the microscopic structures characterized by radial distribution functions. Both of the results of the excess energies and microscopic properties show that the strongest interaction is between [hmim][FEP] and dimethyl ether, whereas the interaction between [hmim][FEP] and water is the weakest. Moreover, [hmim][FEP] is more hydrophobic than [hmim] hexafluorophosphate ([PF6]), and the three solutes are mainly distributed around [FEP] anion.Tris（pentafluoroethyl）trifluorophosphate （[FEP]）-based ionic liquids have been widely applied in many fields. For better un- derstanding the properties of [FEP]-based ionic liquids, the interactions between 1-hexyl-3-methylimidazolium （[hmim]）[FEP] and small molecules were investigated by molecular dynamics simulations in this work. The small molecules are water, meth- anol and dimethyl ether. The united-atom （UA） force fields were proposed for methanol and dimethyl ether based on AMBER force field. The densities, enthalpies of vaporization, excess molar properties, and diffusion coefficients of the mixtures were calculated, as well as the microscopic structures characterized by radial distribution functions. Both of the results of the excess energies and microscopic properties show that the strongest interaction is between [hmim][FEP] and dimethyl ether, whereas the interaction between [hmim][FEP] and water is the weakest. Moreover, [hmim][FEP] is more hydrophobic than [hmim] hexafluorophosphate （[PF6]）, and the three solutes are mainly distributed around [FEP] anion.

关 键 词：ionic liquid tris（pentafluoroethyl）trifluorophosphate small molecule interaction molecular dynamics simulations 

分 类 号：TQ245.12[化学工程—有机化工] TG111.4[金属学及工艺—物理冶金]