Densities (rho) and speed of sound (u) of the binary mixtures of tributyl phosphate (TBP) and alkanes (n-hexane, cyclohexane, and n-heptane) were measured at temperatures from (298.15 to 323.15) K over the entire composition range and at atmosphere pressure. Using these experimentally determined quantities, the excess molar volume (V-E), deviation in isentropic compressibility (Delta k(s)), internal pressure (pi), solubility parameter (delta) and excess cohesive energy of mixing (U-E) have been calculated. The excess molar volume and deviation in isentropic compressibility data have been fitted to a Redlich-Kister type polynomial equation. The positive or negative deviations shown by these quantities have been interpreted in terms of intermolecular interactions and structure of components. (C) 2012 Elsevier Ltd. All rights reserved.