The separation of propylbenzene from dodecane or tetradecane using different ionic liquids (ILs) based on the methylsulfate anion (CH3SO4-) was studied at two temperatures (313 and 333)K and atmospheric pressure. The ionic liquids, 1, 3-dimethylimidazolium methylsulfate [(mmim)(CH3SO4)] and 1-ethyl-3-methylimidazolium methylsulfate [(emim)(CH3SO4)], were evaluated as solvents for the extraction process. Four ternary systems were formed by {dodecane or tetradecane + propylbenzene + [(mmim)(CH3SO4)] or [(emim)(CH3SO4)]}. The degree of quality of the experimental data was ascertained using the Othmer-Tobias correlation. A comparison of the phase behaviour of the systems studied has allowed us to investigate the effect of ILs cation, alkane chain length, temperature and solvent-to-feed ratio upon solubility, percent aromatic removal, distribution ratio, and selectivity. Finally, the experimental LLE data was correlated using the UNIQUAC and the NRTL models. (C) 2013 Elsevier B.V. All rights reserved.