Abstract Since ionic liquids are increasingly employed as separation media in separation technologies, the development of thermodynamic model for design and optimization of the corresponding separation operations is very urgent. At present, the widely used thermodynamic models treat ionic liquid as a non-electrolyte or strong electrolyte. Although the calculation results are close to the experimental results, the treatment of ionic liquid does not consistent with the physical fact that ionic liquids ionize in solution, even in pure ionic liquid. In this work, we proposed a modified model for the calculation of the phase behavior of ionic liquid containing systems. The model combines a term of the modified Debye-Huckel type with a UNIQUAC equation and treats ionic liquid as a weak electrolyte, using an empirical expression to describe the ionization of ionic liquid. The new model has been utilized to correlate the vapor-liquid equilibrium, liquid-liquid equilibrium, solid-liquid equilibrium data as well as infinite dilution activity coefficient for ionic liquid containing systems with high accuracy. Besides, the model can be used to quantitatively describe the ionization behavior of ionic liquid.

中文翻译：

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一种用于计算含离子液体系统相平衡的修正 UNIQUAC 模型

摘要 由于离子液体在分离技术中越来越多地用作分离介质，因此开发用于设计和优化相应分离操作的热力学模型非常紧迫。目前，广泛使用的热力学模型将离子液体视为非电解质或强电解质。虽然计算结果与实验结果接近，但离子液体的处理与离子液体在溶液中电离的物理事实不一致，即使在纯离子液体中也是如此。在这项工作中，我们提出了一种用于计算含有离子液体的系统的相行为的修正模型。该模型将修正的 Debye-Huckel 型项与 UNIQUAC 方程相结合，并将离子液体视为弱电解质，使用经验表达式来描述离子液体的电离。新模型已用于高精度关联含离子液体系统的气液平衡、液液平衡、固液平衡数据以及无限稀释活度系数。此外，该模型可用于定量描述离子液体的电离行为。