Abstract:

An all-atom model of the ionic liquid 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([bmim] [Tf₂N]) was established. Molecular dynamics simulations were carried out at five different temperatures and five different pressures. The simulation results of [bmim][Tf₂N] density were in good agreement with the experimental results, which verified the accuracy of the model. In addition, the interaction energy of [bmim][Tf₂N] changes with temperature and pressure is analyzed. The results show that the Coulomb energy, van der Waals energy and long-range energy in the ionic liquid increase with temperature and the time required for the system to reach equilibrium becomes shorter. Relative to temperature, pressure has less influence on the internal interaction energy of the ionic liquid. Among various interaction energies, van der Waals has maximum energy change varing with temperature and pressure. Temperature and pressure have no effect on the configuration of the ionic liquid.

Key words: ionic liquid, molecular simulation, kinetics, model, interaction energy

摘要：

建立了离子液体1-正丁基3-甲基咪唑双（三氟甲基磺酰基）酰亚胺（[bmim][Tf₂N]）的全原子模型，并分别在五种不同的温度和五种不同的压力下对其进行了分子动力学模拟。将[bmim][Tf₂N]密度的模拟结果与实验结果进行了比较，两者吻合良好，验证了模型准确性。此外，还对[bmim][Tf₂N]内部的相互作用能随温度和压力的变化规律进行了分析，结果表明：离子液体内部的库仑能、范德华能、长程作用能均随温度的升高而增加，系统达到平衡所需时间随之变短；相对温度而言，压力对离子液体内部相互作用能的影响较小；在各种相互作用能中，范德华能随温度和压力的变化最大；温度和压力对离子液体的构型不会产生影响。

关键词: 离子液体, 分子模拟, 动力学, 模型, 相互作用能