The experimental densities of sulfolane (TMS) + 1, 5-pentanediol at 293.15–313.15 K and refractive index at 298.15–308.15 K were reported and expressed by mole fraction of 1, 5-pentanediol. The experimental data of density were used to calculate the excess molar volume, partial molar volume, excess partial molar volume, apparent molar volume, partial molar volumes at infinite dilution, apparent molar volumes at infinite dilution, coefficient of thermal expansion, and excess coefficient of thermal expansion. The deviations in refractive index data were calculated by the Reis equation. Also, the deviations in refractive index and the excess molar volume were fitted using the Redlich-Kister polynomial equation to derive the binary adjustable parameters and standard errors. To probe the interactions and to correlate the excess molar volumes of the examined mixtures, the Prigogine−Flory−Patterson (PFP) theory has been used. The experimental values of refractive indiceswere examined with two semi-empirical equations of Heller and Edward models. To evaluate the validity of the proposed equations, comparisonswere made among the experimental and predicted data. The results are discussed in terms of the intermolecular interactions.
