Hydrophobic interactions in the aqueous solutions of alkane-1,2-diols. Calorimetric and spectroscopic studies at 298.15 K.

Enthalpies of diln. in water were detd. for ternary aq. solns. contg. two of the following alkane-1,2-diols: ethane-1,2-diol, propane-1,2-diol, butane-1,2-diol, pentane-1,2-diol and hexane-1,2-diol. The derived enthalpic interaction coeffs. are interpreted in terms of the interaction of two hydrated mols. through a preferential orientation, side on, stabilized by the prefered interaction between the hydroxyl groups. Other effects are considered, which lead to a unifying rationalization, common to alkanols and other isomeric diols. Further evidence for a side on orientation is given by nuclear relaxation time studies on the binary and ternary aq. solns. of propane-1,2-diol and hexane-1,2-diol.