The solubilities of glutaric acid in binary cyclohexane + cyclohexanol solvent mixtures at 298.05− 343.65 K, in binary cyclohexane + cyclohexanone solvent mixtures at 299.10−340.65 K, in binary cyclohexanone + cyclohexanol solvent mixtures at 299.75−343.65 K, and in ternary cyclohexanol + cyclohexanone + cyclohexane solvent mixtures at 298.15−330.95 K were studied by the dynamic method. The results show that the solubility of glutaric acid increases as temperature increases at constant solvent composition in three determined binary solvent systems. For binary cyclohexane + cyclohexanol and cyclohexane + cyclohexanone solvent mixtures, solubilities of glutaric acid decrease monotonically with the increasing mass fraction of cyclohexane in solvent mixtures at constant temperature. However, for binary cyclohexanone + cyclohexanol solvent mixtures, cyclohexanone with a mass fraction at 0.6 in solvent mixtures has the best dissolving capacity for glutaric acid at constant temperature. The experimental solubility data of three determined binary solvent systems were correlated by the Apelblat equation and nonrandom two-liquid (NRTL) activity coefficient model, and the correlated solubilities data were in good accord with the experimental data. The obtained binary interaction parameters for the NRTL model were used to calculate the solubilities of glutaric acid in the ternary cyclohexanol + cyclohexanone + cyclohexane solvent mixtures, which were compared with the experimental solubilities data.

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The solubilities of phthalic acid and o-toluic acid in binary acetic acid (HAc) + water and HAc + o-xylene solvent mixtures were measured by a dissolution temperature method at atmospheric pressure. The mole fractions of HAc in the corresponding solvent mixtures range from 0.00 to 1.00. The measured data show that, within the temperature range studied, the solubilities of phthalic acid and o-toluic acid increase with the increasing temperature at constant solvent composition and initially decrease with the decreasing mole fraction of HAc in HAc + o-xylene and HAc + water solvent mixtures at constant temperature, respectively. It also shows that, within the solvent composition range studied, the HAc + water solvent mixtures with the mole fraction of HAc at 0.5467 has the highest dissolving capacity for phthalic acid at constant temperature, and the highest solubility of o-toluic acid is obtained in HAc + o-xylene solvent mixtures with the mole fraction of HAc of 0.5408 at constant temperature. The experimental solubilities were correlated by both the nonrandom two-liquid (NRTL) and Apelblat equations, and the calculated solubilities within ±11.9% relative deviation agree satisfactorily with the measured results.

Mononitro-substituted products derived from the nitration of m-toluic acid are 3-methyl-4-nitrobenzoic acid, 3-methyl-2-nitrobenzoic acid, and 5-methyl-2-nitrobenzoic acid, which are all crucial intermediates of pesticides and medicines. The solubilities of 3-methyl-4-nitrobenzoic acid, 3-methyl-2-nitrobenzoic acid, and 5-methyl-2-nitrobenzoic acid in water, methanol, ethanol, n-propanol, formic acid, acetic acid, and propanoic acid were measured at different temperatures (297.65−351.75 K) and under atmospheric pressure. As expected, the same solute has different solubilities in different solvents, and the dissolved amounts of these three solutes are also diverse in the same solvent. Subsequently the experimental solubility data of three mononitro-substituted products of m-toluic acid nitration in several solvents were correlated with the modified Apelblat equation and the NRTL activity coefficient model, and the calculated values are in excellent agreement with known experimental data in the temperature range studied.