Physical Properties of Binary Liquid Systems: Ethanoic Acid/Propanoic Acid/Butanoic Acid with Cresols

Density, viscosity and surface tension of nine binary liquid systems: ethanoic acid, propanoic acid and butanoic acid with o-cresol, m-cresol and p-cresol have been determined at 298.15, 308.15 and 318.15 K over the complete compositional range. From the experimental results the excess values of molar volume (V-E), viscosity (eta(E)), Gibbs free energy for the activation of flow (Delta G(E)) and surface tension (sigma(E)) were evaluated. The excess values were fitted to the Redlich-Kister type equation using a nonlinear regression technique. The Grunberg-Nissan parameter, d, was also calculated. From the sign and magnitude of the V-E, eta(E), Delta G(E), sigma(E), and d values, it is concluded that specific interactions are present in all of the nine binary mixtures under study. V-E is negative for carboxylic acid-cresol mixtures at all temperatures and over the entire composition range. The values of eta(E), Delta G(E) and sigma(E) are positive over the whole range of composition and increase with increasing temperature at a constant mole fraction of the carboxylic acid, confirming the existence of specific interactions in these binary mixtures. Further, the viscosity data of the binary systems were fitted to various theoretical/empirical models. The binary viscosity data is well represented by the Auslander model. Surface tension data were fitted to various theoretical/empirical models. The binary mixture surface tension data are well represented by the model given by Zihao and Jufu.