Under atmospheric pressure, the solubilities of adipic acid, glutaric acid, and succinic acid in acetic acid + cyclohexanone mixtures were measured respectively by using the laser dynamic method in which the temperature ranged from 298.55 to 340.85 K and the mass fraction of cyclohexanone in the binary solvent mixtures ranged from 0.0 to 1.0. The results showed that the solubilities of adipic acid, glutaric acid, and succinic acid in acetic acid + cyclohexanone solvent mixtures all increased with decreasing of the mass fraction of cyclohexanone in the solvent mixtures at the constant temperature, and with the gradually increasing of temperature the measured solubilities of adipic acid, glutaric acid and succinic acid in acetic acid + cyclohexanone solvent mixtures would increase at the constant proportion solvent mixtures. The λh equation and the nonrandom two liquid (NRTL) activity coefficient model were used to correlate the experimental solubilities, and the average relative deviation was lesser than 2% respectively. It was found that the solubilities calculated by these models showed a good agreement with the experimental observations. In addition, the λh equation with a small number of adjustable parameters is very suitable for engineers so that they could use directly. Compared with the λh equation, the NRTL equation has a wider range of applications due to the stronger theory.

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.