Densities and refractive indices for (acetone + methanol + 2-butanol) and the enclosed binary systems (acetone + 2-butanol) and (methanol + 2-butanol) have been measured at T = 298.15 K and atmospheric pressure. Values of densities, refractive indices, excess molar volumes, and changes of refractive indices on mixing were compared with the results obtained by different estimation methods. Parameters of analytical expressions which represent the composition dependence of physical properties and excess values are reported. The binary mixtures described in this paper show positive deviations in the derived properties, as well as changes of refractive indices on mixing for the ternary mixture, while excess molar volumes show negative behaviour at low compositions of the heavy alcohol. Results of these measurements have been applied to calculate partial excess molar volumes and limiting partial excess molar volumes at infinite dilution in binary mixtures, which can be applied as a basis for understanding the molecular interactions in (alcohol + alcohol) and (alcohol + ketone) mixtures according to sign and trend. (C)1999 Academic Press.