Solubility Measurement and Thermodynamic Modeling of Benzoic Acid in Monosolvents and Binary Mixtures

The solid–liquid equilibrium of benzoic acid has been determined in six monosolvents—tributyl phosphate, diacetone alcohol, methyl-n-propyl ketone, methyl acetate, amyl acetate, and isooctane—at temperatures from 283.15 to 328.15 K and five binary systems—ethanol + hexane (288.15–328.15 K), isopropyl alcohol + hexane and chloroform + hexane (288.15–323.15 K), acetone + hexane (288.15–318.15 K), and acetone + water (288.15–318.15 K)—at atmospheric pressure with varying mole fraction of the binary mixture. The solubility was estimated by three different methods—titrimetry, gravimetry, and high-pressure liquid chromatography methods. The solubility of benzoic acid was found to increase with an increase in temperature and mole fraction. Experimental solubility data was correlated with various thermodynamic models such as the Buchowski equation, the NRTL model, and the modified Apelblat–Jouyban–Acree model. The mathematical models demonstrated that the calculated and experimental solubilities of benzoic acid i...