物理化学学报 >> 2014, Vol. 30 >> Issue (12): 2210-2215.doi: 10.3866/PKU.WHXB201410151

热力学,动力学和结构化学 上一篇    下一篇

分子动力学模拟研究[Bmim][PF6]+水+醇三元体系的微观结构和分子间相互作用

梅清清, 侯民强, 宁汇, 马珺, 杨德重, 韩布兴   

  1. 中国科学院化学研究所, 中国科学院胶体界面与化学热力学重点实验室, 北京分子科学国家实验室, 北京 100190
  • 收稿日期:2014-08-16 修回日期:2014-10-15 发布日期:2014-11-27
  • 通讯作者: 侯民强, 韩布兴 E-mail:Houmq@iccas.ac.cn;hanbx@iccas.ac.cn
  • 基金资助:

    国家自然科学基金(21133009, U1232203)资助项目

Microstructure and Intermolecular Interactions of [Bmim][PF6]+Water+ Alcohol Systems: A Molecular Dynamics Simulation Study

MEI Qing-Qing, HOU Min-Qiang, NING Hui, MA Jun, YANG De-Zhong, HAN Bu-Xing   

  1. Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
  • Received:2014-08-16 Revised:2014-10-15 Published:2014-11-27
  • Contact: HOU Min-Qiang, HAN Bu-Xing E-mail:Houmq@iccas.ac.cn;hanbx@iccas.ac.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21133009, U1232203).

摘要:

研究离子液体体系的微观结构和分子间相互作用具有重要意义. 本文对1-丁基-3-甲基咪唑六氟磷酸盐([Bmim][PF6])+水+乙醇和[Bmim][PF6]+水+异丙醇三元体系进行了分子模拟研究, 计算了径向分布函数和不同组成的水-醇混合溶剂与离子液体阴阳离子间的相互作用能, 并将其分解为库仑相互作用能和Lennard-Jones(LJ)势能. 在此基础上, 研究了溶液体系的微观结构、分子间相互作用和相行为. 结果表明, 水倾向于与离子液体阴离子和阳离子极性部分作用, 醇倾向于与阴离子和阳离子非极性部分作用; 库仑力主导阴离子-溶剂相互作用, 色散力主导阳离子-溶剂相互作用, 阴阳离子的缔合状态对色散力影响较小, 对库仑力的影响非常显著.

关键词: 离子液体, 混合溶剂, 三元系, 库仑作用, Lennard-Jones作用, 分子动力学模拟

Abstract:

Studying the microstructure and intermolecular interactions of ionic liquid (IL) systems is of great importance. In this work, molecular dynamics (MD) simulations were performed on 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6])+water+ethanol and [Bmim][PF6]+water+isopropanol ternary systems. Radial distribution functions were calculated, and the interaction energies between ion pairs and mixed solvents of different compositions were decomposed into Coulombic interaction energies and Lennard-Jones (LJ) potentials. The microstructure and intermolecular interactions of the ternary systems were studied based on the results, and the phase behaviors of the systems were discussed. The results show that water tends to interact with the anion and polar part of the cation, while alcohols prefer to interact with the anion and nonpolar part of the cation. The Coulombic interaction dominates over the anion-solvent interaction, while the LJ interaction dominates over the cation-solvent interaction. The association state of the ion pair has a small effect on the LJ interaction, but a significant effect on the Coulombic interaction.

Key words: Ionic liquid, Mixed solvent, Ternary system, Coulombic interaction, Lennard-Jones interaction, Molecular dynamics simulation

MSC2000: 

  • O642