Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Densities of glycine, l-alanine, and l-serine in aqueous solutions of N-methylformamide (NMF) were measured at 298.15 K. The standard partial molar volumes (Vdeg ), standard partial molar volumes of transfer (?trVdeg ) and hydration numbers for the amino acids were also determined. It is shown that hydrophilic-hydrophilic interactions between charged groups of amino acids and the -CONH- group of NMF are predominant in the case of glycine and l-serine. For l-alanine, however, in NMF solutions with m less than 1.5 mol*kg-1, the interaction between the alanine -CH3 group and NMF weakens the interaction between its charged group and the hydrophilic group of NMF, while for NMF solutions with m greater than 1.5 mol*kg-1, the hydrophilic-hydrophilic interactions increase with the increasing concentration of NMF. The results are interpreted in terms of a cosphere overlap model.