Solubility of Isophthalic Acid and M-Toluic Acid in Eight Monobasic Alcohols: Experimental Measurements and Thermodynamic Modeling

In this study, the solubility of isophthalic acid (IPA)and m-toluic acid (m-TA) in eightmonobasicalcohols, methanol, ethanol, 1-propanol, iso-propanol, 1-butanol,iso-butanol, tert-butanol, and 2-butanol is measured under 101.3 kPaby the method of laser dynamics. The experimental temperature rangeis 294.35-360.75 K. The measured data showed that the solubilityof IPA and m-toluic acid increased with the increaseof temperature in the measured temperature range. At the same temperature,the solubility of m-toluic acid in the same puresolvent is higher than that of IPA. The solubility of IPA and m-toluic acid in eight solvents decreased with the increaseof the number of carbon atoms of the solvent. At the same temperature,the solubility ratio of m-toluic acid to IPA in iso-butanolis the highest in the same solvent, and the ratio was greater than70, making it the best solvent for separating IPA and m-toluic acid. The Apelblat model, the Buchowski-Ksiazczak & lambda;h model, and the modified nonrandom two-liquid activity coefficientmodel were used to correlate the experimental data, and the calculatedsolubility was in good agreement with the measured result. The calculatedsolubilities were in good fit with the measured results. The thermodynamicproperties were calculated, and the main contributor of the standardmolar Gibbs energy of IPA and m-toluic acid in eightalcohols is enthalpy, about 55.40 to 82.86%.