Efficiency of hydroxyl groups in promoting hydrophobic interactions. A calorimetric study of ternary aqueous solutions of alkan-1-ols and alkane-m,n-diols.

Heats of dilution of ternary aqueous solutions containing alkan-1-ols and alkane-1,2-diols or alkane-alpha,omega -diols have been determined at 298.15 K by flow microcalorimetry. The pairwise interaction coefficients of the virial expansion of the excess enthalpies were evaluated and compared to those formerly obtained for binary aqueous solutions of alkan-m-ols or alkane-m,n-diols. The results were interpreted using the "preferential configuration" model, namely in terms of preferential interactions between hydrophilic domains and of repulsive interactions between hydrophobic and hydrophilic domains. Hydroxyl groups present a different efficiency in promoting hydrophobic interactions in dependence of their number and position in the interacting molecules. (C) 2000 Elsevier Science B.V. All rights reserved.