Ternary (liquid + liquid) equilibrium data are presented for mixtures of 1-hexyl-3-methylimidazolium (tetrafluoroborate or hexafluorophosphate) + benzene + (heptane or dodecane or hexadecane) at T = 298.2 K. The tie line compositions of the conjugate solutions were obtained by means of density measurements and a standard density calibration curve. Large regions of immiscibility (increasing in the order of hexadecane > dodecane > heptane) and favourable skewing of the tie lines towards the solvent axis provide indications of the favourable use of the ionic liquids in solvent extraction. Selectivity values computed from the experimental data confirm this. Correlation of the experimental tie lines was conducted through the use of the NTRL equation, which provides good correlation of the experimental data. (c) 2004 Elsevier Ltd. All rights reserved.