Solubility predictions for solid nitriles and tertiary amides based on the mobile order theory.

The solubilities of hexadecanenitrile, octadecanenitrile, N,N-diphenyl capramide, and N,N-diphenyl lauramide are predicted in common organic nonelectrolyte solvents using the solubility equation derived from the mobile order theory. In the framework of this theory, the formation of hydrogen bonds is treated on the basis of stability constants. Two values characterizing the nitrile-alcohol and the tertiary amide-alcohol hydrogen bonds, 175 and 600 cm3 mol-1, respectively, are determined. Although the formation of solute-solvent specific molecular interactions brings about a net increase in the solubility, the solubilities of the nitriles and amides in alcohols remain lower than those measured in nonassociated solvents because of the large negative hydrophobic effect of the alcohol molecules.