Instituto de Tecnología Química e Biológica, UNL, Av. República 127, 2780-901 Oeiras, Portugal.
J Phys Chem B. 2010 Dec 9;114(48):15925-34. doi: 10.1021/jp1093788. Epub 2010 Nov 15.
Despite many previous important contributions to the characterization of the liquid-liquid phase behavior of ionic liquids (ILs) plus water systems, a gap still exists as far as the effect of isomers (of ILs) is concerned. Therefore, in this work, a comprehensive study of the liquid-liquid equilibria between water and isomeric pyridinium-based ionic liquids has been performed. Atmospheric pressure mutual solubilities between water and pyridinium-based ionic liquids combined with the common anion bis[(trifluoromethyl)sulfonyl]imide were experimentally determined between (288.15 and 318.15) K. The main goal of this work is to study the isomeric effects on the pyridinium-based cation, namely, the structural and positional isomerism, as well as the alkyl side chain length. To the best of our knowledge, the influence of both structural and positional isomerism on the liquid-liquid behavior in ionic-liquid-water-containing systems is an unexplored field and is here assessed for the first time. Moreover, from the experimental solubility data, several infinite dilution molar thermodynamic functions of solution, namely, the Gibbs energy, the enthalpy, and the entropy, were estimated and discussed. In addition, aiming at gathering a broader picture of the underlying thermodynamic solvation phenomenon, molecular dynamics simulations were also carried out for the same experimental systems.
尽管之前有许多关于离子液体 (ILs) 加水电相行为特性的重要贡献，但在异构体 (ILs) 的影响方面仍存在差距。因此，在这项工作中，我们对水和具有异构体的吡啶基离子液体之间的液-液相平衡进行了全面研究。常压下，水和吡啶基离子液体与常见阴离子双 (三氟甲基磺酰基) 亚胺之间的互溶性在 (288.15 和 318.15) K 之间进行了实验测定。这项工作的主要目的是研究吡啶基阳离子的异构体效应，即结构和位置异构以及烷基侧链长度。据我们所知，结构和位置异构对含离子液体-水体系的液-液行为的影响是一个尚未探索的领域，我们首次对此进行了评估。此外，从实验溶解度数据中，我们还估算并讨论了几个无限稀释摩尔热力学函数，即吉布斯能、焓和熵。此外，为了更全面地了解潜在的热力学溶剂化现象，我们还对相同的实验体系进行了分子动力学模拟。
