Measurement and Correlation for Solubilities of Adipic Acid in Acetic Acid + ε-Caprolactone Mixtures and Cyclohexanone + ε-Caprolactone Mixtures

The solubilities of adipic acid in acetic acid + ε-caprolactone mixtures and in cyclohexanone + ε-caprolactone mixtures were measured by using the method of dynamic laser under atmospheric pressure. The experimental temperature ranged from 305.55 to 343.15 K, and the mass fraction of ε-caprolactone in the solvent mixtures ranged from 0.100 to 1.000, respectively. It was found that with the increasing of mass fraction of ε-caprolactone in solvent mixtures (0.100 to 1.000), the measured solubilities of adipic acid in acetic acid + ε-caprolactone mixtures decreased at the same temperature. However, in cyclohexanone + ε-caprolactone mixtures, the solubility showed an opposite trend with the increasing of mass fraction of ε-caprolactone in solvent mixtures. The experimental data were correlated by the modified NRTL activity coefficient model, and the values of the solubility calculated showed good agreement with the experimental observations.