A model for the interaction between hydrophilic and hydrophobic solutes. A calorimetric study of the aqueous solutions containing alkylureas and urea at 298.15 K.

The heats of dilution of ternary aqueous solutions of urea and alkylureas and of ternary aqueous solution of mono, di and tetra alkylureas have been determined calorimetrically at 298.15 K. Pairwise cross interaction coefficients of the virial expansion of the excess enthalpies were determined. The behaviour of these systems was interpreted in terms of preferential interactions between hydrophilic domains and of repulsive interactions between hydrophobic and hydrophilic domains.