This study reports experimental data and modeling results for the partitioning of 2,5-hexanediol and 2,5-hexanedione - two structurally similar biomolecules - on coexisting liquid phases of the high-pressure vapor-liquid-liquid equilibrium in the ternary system (ethene + water + 2-propanol) at 293 and 333 K and at pressures LIP to 17 MPa. The experiments were performed with an analytical view cell at very low solute concentrations (about 2 g dm(-3)), so that the phase equilibrium of the ternary system remained practically unaffected by the fourth compound and the results for the partition ratio of the solute are at nearly infinite dilution. The new experimental results are correlated using the modification of Melhem et al. for the Peng-Robinson equation of state with two different mixing rules and estimated pure component parameters of the solutes. 0 2006 Elsevier B.V. All rights reserved.