Measurements and modeling of the phase equilibria for the n-hexane + ethanol + dibutyl ether ternary mixture and its dibutyl ether sub-binary mixtures at 94 kPa

Abstract

Experimental determinations and theoretical calculations of the phase equilibria for the n-hexane + ethanol + dibutyl ether ternary mixture and the n-hexane + dibutyl ether and ethanol + dibutyl ether binary mixtures are reported in this work at 94 kPa and over the isothermal range 332.3 K to 401.8 K. At the explored conditions, the phase equilibria are characterized by vapor liquid equilibria (VLE) which are measured in an all-glass dynamic VLE cell, whereas the theoretical modeling of the experimental VLE data are carried out by applying classical activity coefficients models (Wilson, and NRTL models), UNIQUAC method, and the molecular based statistical associating fluid theory with variable range using a Mie potential (SAFT-VR Mie) equation of state (EoS).Considering the experimental determinations, the VLE exhibits positive deviation from the Raoult’s law and a zeotropic behavior under the isobaric condition and the isothermal range. The thermodynamical trustworthiness of the measured VLE data is verified by standard consistency test for both binary and ternary mixtures. Based on the statistical evaluation of the dew and bubble points, the Wilson model displays the lower deviations for correlating the VLE of binary mixtures and also to predict the ternary mixture, but the SAFT-VR Mie EoS approach demonstrates a superior capability to model the phase equilibrium of the binary mixtures and to predict the ternary mixture. Finally, it is possible to state that the polarization contribution is not necessary for the mixtures explored in this work.