The fluid phase behavior of liquid–liquid equilibrium (LLE) is an important piece of the separation processes in chemical engineering, mainly for solvent extraction or liquid–liquid extraction. In this work, experimental studies were carried out in the LLE of a ternary system composed of water, ethanol, and ethyl acetate at four different temperatures at atmospheric pressure. A two-step procedure was done for each temperature in the experimental stage. First, the construction of the binodal curve of the ternary system, and second, the determination of the tie-lines (LLE). For the tie-lines, because the configuration of the binodal curve and the refractive index of the liquid phases at equilibrium were known, their compositions were determined. The LLE experimental data were evaluated through the method developed by Marcilla and collaborators. The gamma–gamma approach was used for the modeling, by using the analytical solutions of groups (ASOG), the nonrandom two-liquids (NRTL), and the universal quasichemical (UNIQUAC) models. Results of the thermodynamic modeling were compared with the experimental values, and the deviations of the compositions of the lighter phase were very low for the thermodynamic models used.

中文翻译：

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乙酸乙酯+乙醇+水系统在大气压下的相平衡热力学行为：实验和建模

液-液平衡（LLE）的液相行为是化学工程分离过程中的重要部分，主要用于溶剂萃取或液-液萃取。在这项工作中，在由水，乙醇和乙酸乙酯组成的三元体系的LLE中，在大气压下的四个不同温度下进行了实验研究。在实验阶段对每个温度进行了两步操作。首先，建立三元系统的二元曲线，其次，确定联络线（LLE）。对于联络线，由于已知二倍体曲线的构型和处于平衡状态的液相的折射率，因此确定了它们的组成。LLE实验数据通过Marcilla和合作者开发的方法进行评估。通过使用组的解析解决方案（ASOG），非随机两种液体（NRTL）和通用拟化学（UNIQUAC）模型，将gamma-gamma方法用于建模。将热力学模型的结果与实验值进行了比较，对于所使用的热力学模型，较轻相的组成偏差非常小。