WATER-ENHANCED SOLVATION OF ORGANIC SOLUTES IN KETONE AND ESTER SOLVENTS

Previous research has shown that the solubilities of dicarboxylic acids in certain electron-donor solvents are substantially increased in the presence of water. Information on solubilities, liquid-liquid equilibria and maximum-boiling ternary azeotropes was screened so as to identify other systems where codissolved water appears to enhance solvation of organic solutes in solvents. Several carboxylic acids, an alcohol, diols, and phenols were selected for examination as solutes in ketone and ester solvents. Effects of water upon solute solubilities and volatilities were measured. Results showed that water-enhanced solvation is greatest for carboxylic acids. Solute activity coefficients decreased by factors of 2-3,6-8, and 7-10 due to the presence of water for mono-, di- and tricarboxylic acids, respectively. Activity coefficients decreased by a factor of about 1.5 for ethanol and 1,2-propanediol as solutes. Water-enhanced solvation of phenols is small, when existent.