Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Vapor-liquid equilibrium (VLE) data were measured for a ternary system containing ionic liquid (IL) water (1) + ethanol (2) + [hmim]Cl (3) at p = 100 kPa. While the mole fraction of ethanol on IL-free basis was fixed at, respectively 0.1, 0.2, 0.4, 0.6, 0.8, and 0.98, the measurements were performed in a way in which the IL mass fraction varied from 0.8 to 0.1, in an interval of 0.1. Complete T, x, y data were obtained for the six data sets. With the aim to model VLE behavior of the ternary system containing IL, the NRTL equation was used and correlations were performed and compared by use of different objective functions, different experimental data sets, and different binary parameters for water + ethanol available in the literature. As a result, it is generally recommended that VLE of a ternary system containing IL can be modeled by experimental measurement and correlation of two ternary data sets, each of which was measured at IL mass fractions from high to low, while the mole fraction of a volatile component calculated on IL-free basis is fixed at a value close to null for one set or unity for another. In the case of the ternary system in the present work, binary parameters were preferably obtained by correlation of the two data sets, in which the ethanol mole fraction on IL-free basis is respectively 0.1 and 0.98. Consequently, ternary VLE of the six data sets were reproduced, with root mean square deviations of 0.49 K and 0.0042 for, respectively, temperature and vapor-phase mole fraction. The calculated and experimental results were also compared graphically in terms of relative volatility, activity coefficient, and boiling temperature, showing good agreement.