Thermodynamics of alcohols and monosaccharides in aqueous solutions of thiourea at 25°C

The excess enthalpies of 12 ternary aq. solns. of alcs. or monosaccharides contg. thiourea were detd. by flow microcalorimetry at 25°. The coeffs. of the virial expansion of the excess enthalpies are compared with those reported in the literature for the same ternary solns. contg. urea in place of thiourea. The cross-interaction coeffs. are pos. for the thiourea-alc. systems and depend on the length and branching of the alkyl chain of the alcs. They are neg. for the thiourea-monosaccharide systems. Thus, thiourea can be used as a probe to reveal differences in the behavior of families of solutes characterized by the same functional groups. The results can be interpreted in terms of the relative stabilities of hydration cospheres of hydrophobic or hydrophilic solutes toward a chaotropic agent such as thiourea. [on SciFinder(R)]