Phase equilibria and interfacial tensions in the systems ethanol + 2-methoxy-2-methylbutane + hexane

Abstract

Isobaric vapor–liquid equilibrium data have been measured for the ternary system ethanol+2-methoxy-2-methylbutane+hexane at 94kPa and in the temperature range 331–350K. Equilibrium determinations were performed in a vapor–liquid equilibrium still with circulation of both phases. The dependence of interfacial tensions of the ternary mixture on concentration was also experimentally determined at atmospheric pressure and 303.15K, using the maximum differential bubble pressure technique.From the experimental results, it follows that the ternary mixture exhibits positive deviation from ideal behavior. The application of a model-free data treatment approach allows concluding about the reliability of the present vapor–liquid equilibrium data. Furthermore, the determined interfacial tensions exhibit both positive and negative deviations from linear the behavior, and double aneotropy is observed.The vapor–liquid equilibrium data of the ternary mixture were well-predicted by the NRTL, Wilson and UNIQUAC activity coefficient models using binary parameters only. The interfacial tensions were smoothed using the Myers–Scott expansion, showing a significant contribution of parameters that describe three-body interactions, thus suggesting that the ternary IFT data cannot be directly predicted from the binary contributions.