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

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.

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

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.