Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The solubility of benzoic acid in (acetic acid + water) and (acetic acid + toluene) binary mixtures has been investigated by gravimetric method. The study was carried out at different mass fractions of acetic acid ranging from 0.1 to 0.8 at 299.15 K. The results indicated that the solubility of benzoic acid in both the binary mixtures exhibits an increasing trend with increase in the mass fraction of acetic acid. The solubility of benzoic acid with respect to acetic acid is less in (acetic acid + water) mixture as compared to that of (acetic acid + toluene) mixture. Furthermore, the refractive indices, nD, and densities, n, have been measured for (acetic acid + water) and (acetic acid + toluene) binary mixtures as well as mixtures saturated with benzoic acid salt at different temperatures over the entire composition range and the same have been reported. The molar refractivity, Rm, was estimated using refractive index, nD and molar volume, Vm employing Lorentz-Lorenz equation. The excess properties, namely deviations in molar refractivity, AR, excess molar volumes, , were calculated for both the binary mixtures. The deviations in molar refractivity resulted in negative values for both the binary mixtures whereas the excess molar volumes gave negative values for (acetic acid + water) mixture and positive values for (acetic acid + toluene) mixtures. The results obtained in the present study have been discussed in terms of structural packing and interactions present among the mixing components and are fitted to the Redlich-Kister third order polynomial equation. Different mixing rules were also employed to predict the refractive index and compared with experimental values.