Liquid–Liquid Phase Equilibrium for the Ternary System (Water–Ethanol–Ethyl Caprate): Experimental and Modeling

Abstract

The liquid−liquid equilibrium (LLE) of the ternary system (water− ethanol−ethyl caprate) was examined in this study at T = (293.15, 308.15, and 323.15) K and atmospheric pressure. The tie-line data for the studied system at each temperature were determined using the equilibrium still, and the two-phase composition was obtained by gas chromatography. The effect of temperature on the solubility of the ternary system was explored. The ternary phase diagram of the system revealed Treybal's type I phase diagram, where the immiscible zone decreased with increasing temperature. The consistency of the experimental data was assessed by using the Othmer−Tobias and Hand correlation equations. Using the NRTL and UNIQUAC models, the ternary system LLE data at each temperature were correlated. Two models were used to estimate the LLE data, and for both models, the root-mean-square deviations between the experimental and modeled values were less than 0.0164. This suggests that the phase behavior of the ternary systems of water, ethanol, and ethyl decanoate can be well correlated by both models. Moreover, the UNIQUAC model demonstrates better system suitability compared with the NRTL model. The distribution coefficients (D) and separation factors (S) were calculated.