Solubility of Benzoic Acid in Six Alcohols within (288.15 to 336.15 K) and Thermodynamic Properties in the Dissolution Process

Abstract

The solubility of benzoic acid was determined in six alcohols (isobutanol, n-pentanol, isoamylol, 2-pentanol, tert-amyl alcohol and n-hexanol) from (288.15 to 336.15 K) by the dynamic method. The value of solubility rises with the increase of temperature and the order of solvents is tert-amyl alcohol > 2-pentanol > n-hexanol > n-pentanol > isoamylol > isobutanol. The modified Apelblat equation, λh model, NRTL model and Wilson model were adopted to correlate the experimental data of benzoic acid. The results show the solubilities calculated by the models are consistent with the experimental ones and the modified Apelblat equation gives the best correlation results with the overall relative average deviation 0.60%. Meanwhile, the changes of thermodynamic properties of the solution, standard molar enthalpy △_disH°, standard molar entropy △_disS° and standard molar Gibbs energy △_disG°  were calculated with the NRTL model. According to the results, the dissolution of benzoic acid in six alcohols is endothermic and entropy-driven.