Corchero R, Marcilla A, Olaya M M, Carbonell-Hermida P, Soto A
Cretus Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela E-15782 Santiago de Compostela Spain
Chemical Engineering Department, University of Alicante 03080 Alicante Spain.
RSC Adv. 2019 Dec 23;9(72):42524-42532. doi: 10.1039/c9ra09283h. eCollection 2019 Dec 18.
Ionic liquids are being proposed for the improvement of many refinery-related applications where water and oil coexist. However, the lack of relevant thermodynamic data on equilibrium processes involving water, oil and an ionic liquid is a stumbling block. Phase diagrams of these systems are complex, with many different regions, especially when the ionic liquid is solid at room conditions. This greatly complicates modelling, which is usually neglected or carried out only partially. In this work, for the first time, the simultaneous correlation not only of liquid-liquid and liquid-liquid-liquid but also solid-liquid equilibrium data for ternary systems involving ionic liquids has been carried out. To that end, the ionic liquid 1-hexyl-3-methylpyridinium trifluoromethanesulfonate, with an alkyl chain length that favours nano-segregation, was selected. Phase diagrams with water and different representative oils (octane, toluene and cyclohexane) have been determined at various temperatures and atmospheric pressure. The great capacity of the NRTL model, a powerful tool used in all chemical process simulators, was shown by simultaneously correlating data from all the equilibrium regions. However, adequate equilibrium equations and pivotal strategies were required. Low deviations and a good representation of phase diagrams was achieved. A topological analysis based on the Gibbs common tangent criterion and a stability test allowed validation of the proposed correlation parameters.
离子液体被提议用于改善许多水和油共存的炼油相关应用。然而，缺乏关于涉及水、油和离子液体的平衡过程的相关热力学数据是一个绊脚石。这些系统的相图很复杂，有许多不同的区域，特别是当离子液体在室温条件下为固体时。这使得建模变得非常复杂，建模通常被忽略或只进行部分建模。在这项工作中，首次对涉及离子液体的三元体系的液 - 液、液 - 液 - 液以及固 - 液平衡数据进行了同时关联。为此，选择了具有有利于纳米分离的烷基链长度的离子液体1 - 己基 - 3 - 甲基吡啶三氟甲磺酸盐。在不同温度和大气压下测定了与水和不同代表性油（辛烷、甲苯和环己烷）的相图。通过同时关联来自所有平衡区域的数据，展示了所有化学过程模拟器中使用的强大工具NRTL模型的强大能力。然而，需要适当的平衡方程和关键策略。实现了低偏差和相图的良好表示。基于吉布斯公切线准则的拓扑分析和稳定性测试验证了所提出的关联参数。
