Measurement and correlation of liquid-liquid equilibria at different temperatures in water + 1-propanol + 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ternary systems

In order to reduce the environmental impact and the economical costs of the separation of 1-propanol from aqueous mixtures, which enables the recycling of the alcohol, the experimental liquid-liquid equilibria (LLE) data of water (1) + 1-propanol (2) + 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) (3) and water (1) + 1-propanol (2) + 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([hmim][Tf2N]) (3) systems were measured in this work at different temperatures: 283.2, 303.2 and 323.2 K at atmospheric pressure. The results were correlated by non-random two-liquid (NRTL) and universal quasichemical (UNIQUAC) models with good results in both cases (the maximum root-mean-square deviation was 0.57%). Finally, the capability of the two ILs to extract 1-propanol from aqueous solutions was studied and compared with another IL from the literature.