Liquid-liquid equilibrium measurements and correlation for phase behaviors of alcohols + heptane + ILs ternary systems

Highlights: • Liquid-liquid equilibria data of heptane + alcohol + IL were measured. • Influence of alkyl chain length on the liquid-liquid equilibria was discussed. • The NRTL and UNIQUAC models were applied to correlate the studied system. • The UNIFAC model was used to predict these systems with reasonable accuracy. - Abstract: Liquid–liquid equilibrium (LLE) for ternary systems of heptane + alcohols (ethanol, 1-propanol and 2-propanol) + ionic liquids (ILs) were carried out at 298.15 K and atmospheric pressure. The values of distribution coefficient (β) and selectivity (S) were calculated for the systems to investigate the influence of ionic liquids' anion and length of the n-alkyl chain in alcohols on the LLE. The NRTL and UNIQUAC models were used to correlated the experimental data, and the results indicated that both the models fit the experimental systems. The UNIFAC model was used to predict the LLE behaviors of the studied systems and compare with experimental and correlated tie-lines.