Thermodynamic Behavior of the Phase Equilibrium of Ethyl Acetate + Ethanol + Water Systems at Atmospheric Pressure: Experiment and Modeling

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.