Thermodynamics of the interaction of HCl with D-arabinose in water at 278.15-318.15 K

The thermodynamic parameters of interaction of HCl with D-arabinose in wate r were determined from electromotive force measurements from 278.15 to 318. 15 K. The standard Gibbs free energies of transfer of HCl from water to aqu eous solutions of 5, 10, and 15 wt.% of D-arabinose were evaluated. The gro up interaction Gibbs free-energy parameters (G(HCl-CH2), G(HCl-OH), G(HCl-e -OH), G(HCl-a-OH), and G(HCl-O)) for the HCl-sugar (or alcohol)-water syste ms were evaluated and discussed in terms of the Savage-Wood group additivit y principle and the stereochemistry of sugars, where -OH, -e-OH and -a-OH s tand respectively for alcohol-, equatorial- and axial-hydroxyl groups. Of t he five group interactions, the HCl-e-OH interaction contributes a large po sitive value to the pair interaction Gibbs free-energy parameters of HCl wi th sugars, whereas the contributions of the HCl-a-OH and HCl-O interactions are very small. (C) 1999 Elsevier Science Ltd. All rights reserved.