Interactions in aqueous solutions of urea and monosaccharides. Excess enthalpies at 298.15 K

Abstract

The excess enthalpies of nine ternary solutions of urea and monosaccharides have been determined by microcalorimetry at 298.15 K. The coefficients of the virial expansions of the excess enthalpies have been compared with those reported in the literature for other hydroxylated non-electrolytes. By using empirical combining rules among the enthalpic cross- and self-interaction coefficients it is possible to show that, even in the presence of urea, the behaviour of saccharides and of cyclic or linear polyols are all different. The differences are also emphasized by the application of the group-additivity approach.