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

ABSTRACT

In this article the standard free energies (?Gt0(i)) and entropies (?St0(i)) of transfer of four homologous a-amino acids including glycine (Gly), dl-alanine (dl-Ala), dl-a-amino butyric acid (dl-Aba.) and dl-nor-valine (dl-n-Val) from ethylene glycol (EG) to nonaqueous mixtures of ethylene glycol and dimethyl sulfoxide (DMSO) at 298.15 K are reported. The Gibbs energies of solutions have been determined from solubility measurements of each amino acid at different temperatures, that is, from 288.15 to 308.15 K by formol titrimetry . The chemical parts of free energies (?Gt,ch0(i)) and entropies (T?St,ch0(i)) of transfer of the homologous a-amino acids have been computed by subtracting the cavity effects and dipole dipole interaction effects from the total transfer energies. The characteristics of the solvation thermodynamics of a-amino acids in EG-DMF and EG-ACN mixed solvent systems studied earlier are also discussed here for comparison.