The knowledge of liquid-liquid equilibria (LLE) of the ternary systems (hexane or heptane + ethanol + 1-ethyl-3-methylimidazolium ethylsulfate (EMIM EtSO4)) is essential for the separation of alkanes from their azeotropic mixtures with ethanol. The experimental LLE have been determined at 298.15 K and atmospheric pressure. Experimental LLE are correlated using NRTL equation. The solvent capacity of the IL is compared with others aiming to analyze the efficiency of these molten salts used as entrainers. The extraction processes with this IL are simulated using conventional software. A comparison of the alkylsulfate-based IL's ability for the extraction process, determined from the simulation results, is enclosed. (C) 2009 Elsevier B.V. All rights reserved.