The role of hydrophilic interactions in determining preferential configurations in aqueous solution: alkan-1-ols, alkan-1,2-diols, alkan-α,ω-diols, and α-aminoacids interacting with glycine and its oligomers at 298.15 K

Abstract

Enthalpies of dilution of ternary aqueous solutions containing glycine, diglycine or triglycine and alkan-1-ols, alkan-1,2-diols, alkan-α,ω-diols, and α-aminoacids have been determined by microcalorimetry at 298.15 K. Pairwise cross interaction coefficients of the virial expansion of the excess enthalpies were evaluated. The values of these coefficients are positive, depending in a very complex manner on the number and position of the hydroxyl groups. The behaviour of these systems seems to be determined by a balance between favourable hydrophilic—hydrophilic and repulsive hydrophilic—hydrophobic interactions. The chaotropic agents employed play a major role: they are more complex than other purely hydrophilic substances, such as urea or biuret, because of the presence of hydrophobic domains on their molecules.