Original Article
S.Roy, K.Mahali, B.K.Dolui
Abstract
Standard transfer Gibbs energies, ïΓβΓΒΓβΓβG0 t(i) of a series of homologous á-amino acids(i) like glycine (gly), dl-alanine (ala), dl - ïΓβΓΒ¡-amino butyric acid (aba) and dl -nor- valine (n-val) from water to aqueous mixture of protic ethylene glycol (EG) with 0, 20, 40, 60, 80 and 100 wt%EGcompositions have been determined by measuring solubility of these amino acids at 250C using ÂΓβΓβformal titrimetryÂΓβΓβ. The chemical effects of the transferGibbs energies of the á-amino acids(i), ïΓβΓΒΓβΓβG0 t,ch(i) have been obtained by subtracting the cavity effects, ïΓβΓΒΓβΓβG0 t,cav(i),estimated by the scaled particle theory and dipole-dipole interaction effects, ïΓβΓΒΓβΓβG0 t,d-d(i) calculated by means of the Keesom orientation expression. ïΓβΓΒΓβΓβG0 t,ch(i) are dictated by decreased hydrophobic hydration(HbH) and the superimposed increased acidity and increased dispersion effects of EG-water mixtures as compared to that in water.