COMPILATION AND CORRELATION OF LIMITING ACTIVITY-COEFFICIENTS OF NONELECTROLYTES IN WATER

The phase equilibria of dilute aqueous solutions are treated separatel y from those of dilute organic systems due to water's unique structure and hydrogen-bonding characteristics. As a result, traditional predic tive methods (UNIFAC, ASOG, etc.) tend to be only moderately successfu l. In addition to inverse solubility measurements, we describe new dir ect and indirect techniques for precisely measuring these values which are more accurate. A database is compiled from data measured by using these techniques. The data were evaluated and suspect points removed. The data were correlated linearly with the solute solvatochromic alph a, beta, and pi, solute and solvent molar volume, solute vapor pressu re, and the solute gas-liquid partition coefficient between hexadecane and an inert gas phase, log L(16). The correlation fits the data to w ithin an average absolute deviation of 0.294 In units. The correlation provides a direct and relatively accurate method for estimating Henry 's constants and thus limiting activity coefficients of nonelectrolyte s in water.