物理化学学报 >> 2010, Vol. 26 >> Issue (06): 1463-1467.doi: 10.3866/PKU.WHXB20100534

热力学、热化学和溶液化学 上一篇    下一篇

咪唑基离子液体的物理化学性质估算及预测

刘青山, 杨淼, 谭志诚, WELZ-BIERMANN Urs   

  1. 中国科学院大连化学物理研究所, 中国离子液体实验室, 辽宁 大连 116023; 中国科学院大连化学物理研究所, 热化学实验室, 辽宁 大连 116023
  • 收稿日期:2009-11-09 修回日期:2010-02-02 发布日期:2010-05-28
  • 通讯作者: 谭志诚, WELZ-BIERMANN Urs E-mail:tzc@dicp.ac.cn; uwb@dicp.ac.cn

Estimation and Prediction of the Physicochemical Properties of Imidazolium-Based Ionic Liquids

LIU Qing-Shan, YANG Miao, TAN Zhi-Cheng, WELZ-BIERMANN Urs   

  1. China Ionic Liquid Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning Province, P. R. China; Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning Province, P. R. China
  • Received:2009-11-09 Revised:2010-02-02 Published:2010-05-28
  • Contact: TAN Zhi-Cheng, WELZ-BIERMANN Urs E-mail:tzc@dicp.ac.cn; uwb@dicp.ac.cn

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摘要：

根据经验和半经验方程及空隙模型理论, 可以估算及预测离子液体在298.15 K的物理化学性质. 本文讨论了离子液体的分子体积, 密度, 标准熵, 晶格能, 表面张力, 等张比容, 摩尔蒸发焓, 空隙体积, 空隙率和热膨胀系数. 通过实验测得的三种离子液体1-乙基-3-甲基咪唑硫酸乙酯([C2mim][EtSO4)]), 1-丁基-3-甲基咪唑硫酸辛酯([C4mim][OcSO4])和1-乙基-3-甲基咪唑双三氟甲磺酰亚胺盐([C2mim][NTf2])的密度和表面张力估算了它们的其它物理化学性质. 由这三种离子液体的分子体积及等张比容预测了同系列中其它离子液体[Cnmim][EtSO4], [Cnmim][OcSO4]和[Cnmim][NTf2](n=1-6)的分子体积及等张比容, 由此计算出它们的密度及表面张力. 进而预测了它们的物理化学性质. 将预测的离子液体[C4mim][NTf2]和[C2mim][OcSO4]的密度值与文献报导的实验值进行比较, 其偏差在实验误差范围内. 最后, 将由Kabo经验方程计算的七个离子液体[C2mim][EtSO4]、[C4mim][OcSO4]、[C2mim][NTf2]、[C4mim][NTf2]、丁基三甲基铵双三氟甲磺酰亚胺盐([N4111][NTf2])、甲基三辛基铵双三氟甲磺酰亚胺盐([N8881][NTf2])和1-辛基-3-甲基吡啶四氟硼酸盐([m3opy][BF4])的摩尔蒸发焓与由Verevkin简单规则预测的摩尔蒸发焓进行比较, 发现两者符合很好. 因此, 在缺乏密度和表面张力实验数据的情况下, 可以用Verevkin简单规则来预测离子液体的摩尔蒸发焓.

关键词: 离子液体, 密度, 表面张力, 等张比容, 蒸发焓, 分子体积

Abstract:

The physicochemical properties of ionic liquids (ILs) at 298.15 K could be estimated and predicted in terms of empirical and semi-empirical equations as well as by interstice model theory. In this paper, the molecular volume, density, standard molar entropy, lattice energy, surface tension, parachor, molar enthalpy of vaporization, interstice volume, interstice fraction, and thermal expansion coefficient are discussed. These properties were first estimated by experimentally determining the density and surface tension for 1-ethyl-3-methylimidazolium ethylsulfate ([C2mim][EtSO4]), 1-butyl-3-methylimidazolium octylsulfate ([C4mim][OcSO4]), and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][NTf2]). The molecular volume and parachor of the three homologues of the imidazolium-based ILs [Cnmim][EtSO4], [Cnmim][OcSO4], and [Cnmim][NTf2] (n=1-6) were predicted and their densities and surface tensions were obtained. Other properties were also calculated using the obtained density and surface tension values. The predicted density was compared to the experimental values for [C4mim][NTf2] and [C2mim][OcSO4], which shows that the deviation between experimental and predicted data are within experimental error. Finally, we compared the values for the molar enthalpy of vaporization estimated by Kabo's empirical equation with those predicted by Verevkin's simple rule for [C2mim][EtSO4], [C4mim][OcSO4], [C2mim][NTf2], [C4mim][NTf2], N-butyltrimethylammoniumbis (trifluoromethylsulfonyl)imide [N4111][NTf2], N-methyltrioctylammoniumbis(trifluoromethylsulfonyl)imide ([N8881][NTf2]), and N-octyl-3-methylpyridinium tetrafluoroborate ([m3opy][BF4]) and found that the values obtained by these two equations were in good agreement with each other. Therefore, we suggest that the molar enthalpy of vaporization of ILs can be predicted by Verevkin's simple rule when experimental data for density and surface tension are not available.

Key words: Ionic liquids, Density, Surface tension, Parachor, Enthalpy of vaporization, Molecular volume

MSC2000: 

  • O642