Solubility and transfer Gibbs free energetics of glycine, DL-alanine, DL-nor-valine and DL-serine in aqueous sodium fluoride and potassium fluoride solutions at 298.15 K

Abstract

The experimental saturated solubilities of glycine, DL-alanine, DL-nor-valine and DL-serine in aqueous mixtures of NaF and KF solutions at 298.15 K are measured by using an analytical ‘formol titrimetry’ method. Subsequently, the standard transfer Gibbs free energy, enthalpy for cavity formation, Gibbs free energy for cavity formation and Gibbs free energy for dipole-dipole interaction have been computed. The chemical contribution for the standard transfer Gibbs free energies for the experimental amino acids have been obtained by subtracting the cavity effects and dipole-dipole interaction effects from the total standard transfer Gibbs free energy (∆<img src='http://www.niscair.res.in/jinfo/ijcaequation4.gif' border=0> (i)). The stability of the studied amino acids in aqueous NaF and KF in terms of thermodynamic parameters are discussed and compared.