Study of liquid-liquid extraction of ethanol + water azeotropic mixtures using two imidazolium-based ionic liquids

The present work was focused on the study of two imidazolium-based ionic liquids (ILs) as solvents in liquid-liquid extraction of ethanol from aqueous mixtures. With this aim, the experimental liquid-liquid equilibria (LLE) data of water (1) + ethanol (2) + 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) (3) and water (1) + ethanol (2) + 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([hmim][Tf2N]) (4) systems were obtained at different temperatures: 283.2, 303.2, and 323.2 K, in order to check the influence of temperature. The results were correlated by non-random two-liquid (NRTL) and universal quasichemical (UNIQUAC) models with good concordance in both cases. Finally, the ability of the two ILs to act as solvents was studied by evaluating the coefficient distribution and the selectivity of ternary systems and compared with another IL from the literature.