Abstract An ion-specific electrolyte perturbed-chain statistical associating fluid theory (ePC-SAFT) has been developed to describe the thermodynamic and transport properties of ionic liquids (ILs) for developing IL-based technologies to separate CO2 from gas mixtures. However, as it has been pointed out previously, SAFT-based models can lead to a pitfall, manifesting as an additional fictitious liquid-liquid critical line connected to an additional mechanically stable critical point when modeling pure substances. In this work, a method for detecting a pitfall in ILs was developed, where an expression with ionic term for calculating the critical point with ePC-SAFT was derived and an algorithm for detecting the additional fictitious phase equilibrium for ILs was proposed. The pitfall occurrence for an extended set ILs taken from our previous work was investigated. It shows that a pitfall occurs only for one single IL among all 96 ILs in the temperature and pressure range of interest. For [C8mpy][BF4], at 290.27–291.78 K, a pitfall may occur at the pressures of interest; at 273.15–290.20 K, it may occur at any given pressure. The ion-specific ePC-SAFT parameters for [C8mpy]+ may therefore need to be modified in the future when more reliable experimental results are available for parameter fitting.

中文翻译：

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如何检测 ePC-SAFT 建模中可能存在的缺陷：离子液体的扩展

摘要 离子特定电解质扰动链统计缔合流体理论 (ePC-SAFT) 已被开发用于描述离子液体 (IL) 的热力学和传输特性，以开发基于 IL 的技术以从气体混合物中分离 CO2。然而，正如之前所指出的，基于 SAFT 的模型可能会导致一个陷阱，表现为在模拟纯物质时连接到一个额外的机械稳定临界点的额外虚构的液-液临界线。在这项工作中，开发了一种检测 ILs 陷阱的方法，其中推导出了用于计算 ePC-SAFT 临界点的离子项表达式，并提出了一种检测 ILs 额外虚拟相平衡的算法。调查了从我们以前的工作中获取的扩展集 IL 的陷阱发生。它表明，在感兴趣的温度和压力范围内，所有 96 个 IL 中仅一个 IL 出现了缺陷。对于 [C8mpy][BF4]，在 290.27-291.78 K，在感兴趣的压力下可能会出现陷阱；在 273.15–290.20 K，它可能在任何给定的压力下发生。因此，当有更可靠的实验结果可用于参数拟合时，[C8mpy]+ 的离子特定 ePC-SAFT 参数可能需要在未来进行修改。