Solubilities of Benzoic Acid in Binary Methylbenzene + Benzyl Alcohol and Methylbenzene + Benzaldehyde Solvent Mixtures

Abstract

By using the synthetic method, the solubilities of benzoic acid in binary methylbenzene + benzyl alcohol solvent mixtures at (301.05 to 355.65) K and in binary methylbenzene + benzaldehyde solvent mixtures at (301.05 to 354.45) K were determined at atmospheric pressure. The studied mass fractions of benzyl alcohol and benzaldehyde in the corresponding binary solvent mixtures range from 0.0 to 1.0. It was found that the measured solubilities increase with the increase of temperature at constant solvent composition. For the ternary system benzoic acid + methylbenzene + benzyl alcohol, the results show that the binary methylbenzene + benzyl alcohol solvent mixture with the mass fraction of benzyl alcohol at 0.80 has the best dissolving capacity for benzoic acid at constant temperature. However, for the ternary system benzoic acid + methylbenzene + benzaldehyde, the results show that the binary methylbenzene + benzaldehyde solvent mixture with the mass fraction of benzaldehyde of 0.20 has the best dissolving capacity for benzoic acid at constant temperature. The experimental data were correlated by both the nonrandom two-liquid (NRTL) and the Apelblat equations, and the correlated solubilities agree satisfactorily with the experimental observations. By coupling the Apelblat equation with the Clark and Glew equation, the thermodynamic functions for the two studied solid−liquid equilibrium systems, including dissolution enthalpy, entropy, Gibbs energy, and isobaric heat capacity, were calculated and discussed.

Solubility determination and thermodynamic models for dehydroepiandrosterone acetate in mixed solvents of (ethyl acetate + methanol), (ethyl acetate + ethanol) and (ethyl acetate + isopropanol)

“…However there are large deviations between the determined solubility of the benzoic acid in toluene in this work and those reported in Ref. [25]. The deviations may be caused by the experimental apparatus and experimental method.…”

“…1, and they are tabulated in Table 2 together with the relative deviations of our determined solubility with the values taken from the Refs. [23][24][25][26]. Fig.…”

“…The experimental results together with the data in the literature [23][24][25][26] are shown graphically in Fig. 1, and they are tabulated in Table 2 together with the relative deviations of our determined solubility with the values taken from the Refs.…”

“…In Ref. [25], the solubility of benzoic acid in toluene was determined by using the synthetic method; and in this work, they are determined with the isothermal dissolution equilibrium method [11,12].…”

“…RD 1 %, RD 2 %, RD 3 % and RD 4 % are the relative deviations of our determined solubility with the data taken from the Refs. [23][24][25][26], respectively. RD = x e Àx lit x lit , where x e and x lit denote the mole fraction solubility determined in this work and taken from literatures, respectively.…”