Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (12): 2210-2215.doi: 10.3866/PKU.WHXB201410151


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;
  • Supported by:

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


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


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