Solubilities of 1,3,5-Benzenetricarboxylic Acid and 1,3-Benzenedicarboxylic Acid in Acetic Acid + Water Solvent Mixtures

Abstract

Using the static analytical method, the solubilities of 1,3,5-benzenetricarboxylic acid and 1,3-benzenedicarboxylic acid in binary acetic acid (2) + water (3) solvent mixtures have been measured. The experimental temperature ranged from (303.2 to 363.2) K, and the mole fraction of acetic acid in the solvent mixtures ranged from (0.411 to 1.000) for 1,3,5-benzenetricarboxylic acid and x2 = (0.310 to 1.000) for 1,3-benzenedicarboxylic acid. The experimental results showed that, within the temperature range of the measurements, the solubilities of 1,3,5-benzenetricarboxylic acid and 1,3-benzenedicarboxylic acid in all the mixtures showed an increasing trend as the temperature increased. The solubility of 1,3,5-benzenetricarboxylic acid increased with the increasing mole fraction of water. Below 323.2 K, as the mole fraction of water increased in the aqueous acetic acid solution, the solubility of 1,3-benzenedicarboxylic acid decreased within the range of measurements. However, above 323.2 K, the aqueous acetic acid solution, of which the mole fraction of acetic acid was 0.544, was the best solvent for 1,3-benzenedicarboxylic acid. A simple explanation was given for this “maximum-solubility effect”. The present results were compared with the data obtained from our previous work. The experimental solubilities had been correlated with the Buchowski equation, and the calculated results showed good agreement with the experimental solubilities.