(Liquid + liquid) equilibrium (LLE) data of the solubility curves and tie-line end compositions are presented for mixtures of {water (1) + levulinic acid (2) + methylcyclohexanol, or cyclohexanone, or cyclohexyl acetate (3)} at T = 298.2 K and P = (101.3 +/- 0.7) kPa. Among the studied C6 ring-containing cyclic solvents, methylcyclohexanol and cyclohexyl acetate give the largest distribution ratio and separation factors for extraction of levulinic acid. A solvation energy relation (SERLAS) has been used to estimate the (liquid + liquid) equilibria of associated systems containing components capable of a physical interaction through hydrogen bonding. The tie-lines were also predicted using the UNIFAC-original model. The reliability of both models has been analyzed against the LLE data with respect to the distribution ratio and separation factor. SERLAS matches LLE data quite accurately, yielding a mean error of 3.6% for all the systems considered. (c) 2005 Elsevier Ltd. All rights reserved.