Tie line data have been determined at 323.15, 348.15 and 373.15 K for the ternary liquid-liquid equilibria (LLE) of alkane (C10/C12/C14)+ 1,4-diisopropylbenzene + sulfolane systems. The addition of 1,4-diisopropylbenzene to sulfofane is found to increase the solubility of alkanes in the order of n-decane > n-dodecane > n-tetradecane and the relative mutual solubility of 1,4-diisopropylbenzene is higher in n-decane + sulfolane than in n-dodecane + sulfolane or n-tetradecane + sulfolane mixtures. The tie line data were correlated with the well-known UNIQUAC and NRTL models. The calculated equilibrium mole fractions based on the UNIQUAC model are better than those based on the NRTL model. The values of selectivity and distribution coefficient were derived from the equilibrium data.