AN EXPERIMENTAL-METHOD FOR DETERMINING THE HILDEBRAND SOLUBILITY PARAMETER OF ORGANIC NONELECTROLYTES

A three-solvent system was used to determine the Hildebrand solubility parameters of organic nonelectrolytes. The experimental Hildebrand solubility parameter represents a weighted average of the mole fraction solubilities of the solute in these three individual solvents (ethyl acetate, 1-propanol, and 1,2-propanediol). The solvent system estimated the Hildebrand solubility parameters of solutes within a range from 8.9 to 14.8 (cal/cm3)1(2). Deviations ranged from 0.8 to 12.9%, with the highest value at the extreme and well within 10% at the median. Estimation of the Hildebrand solubility parameters of solutes within a wider range and with somewhat better accuracy was made with a five-solvent system (hexane, ethyl acetate, 1-propanol, 1,2-propanediol, and water).