Aqueous solutions containing amino acids and peptides. Part 5.—Gibbs free energy of interaction of glycine with some alkali metal chlorides at 298.15 K

Abstract

Cells with transference have been used to investigate the free energy of interaction of glycine with LiCl, NaCl and CsCl in aqueous solutions at 298.15 K. The experimental data were analysed to give the Lewis–Randall free energy coefficients which represent pairwise interactions between the salt ions and the amino acid. The Lewis–Randall coefficients were transformed to the McMillan–Mayer scale and these were then deconvoluted in an approximate manner to give the contributions arising from excluded volume (hard-sphere), electrostatic (Kirkwood) and solvent reorganisation effects. The excluded volume and solvent reorganisation contributions are found to be approximately equal in magnitude but opposite in sign, so that the frequently used Kirkwood electrostatic model represents the nett interactions well.