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

ABSTRACT

In our experiment, a dynamic method was taken to measure the solubilities of the 2,4-dimethoxybenzoic acid under atmospheric pressure (p = 0.1 MPa) in ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and ethyl acetate as well as in the isopropanol + ethyl acetate mixtures from (288.15 to 323.15) K. The experiment results have proved that the rising temperature leads to increased solubility of the 2,4-dimethoxybenzoic acid in all selected solvents. The changing model parameters in each selected solvent was recorded and calculated, respectively, during the experiments and the solid liquid equilibrium data in pure and mixed solvents was correlated with a series equations, including the modified Apelblat equation, Wilson equation, UNIQUAC equation, and the Jouyban Acree. During the study, the computational values were in good agreement with the experimental results according to the calculations based on all selected equations, however the modified Apelblat equation stood out to be the most suitable with the most accuracy. In addition, some thermodynamic parameters of the solution of 2,4-dimethoxybenzoic acid including dissolution enthalpy (?Hsol), entropy (?Ssol) and the Gibbs energy (?Gsol) were obtained via the van t Hoff analysis. The positive values of?Hsol and?Gsol indicated that the dissolution process of dissolving 2,4-dimethoxybenzoic acid is endothermic.