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

Abstract

The thermodynamic parameters of interaction of HCl with d-arabinose in water 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 aqueous solutions of 5, 10, and 15 wt.% of d-arabinose were evaluated. The group interaction Gibbs free-energy parameters ( G HCl–CH 2 , G HCl–OH, G HCl– e-OH , G HCl– a-OH , and G HCl–O) for the HCl–sugar (or alcohol)–water systems were evaluated and discussed in terms of the Savage–Wood group additivity principle and the stereochemistry of sugars, where –OH, – e-OH and – a-OH stand respectively for alcohol-, equatorial- and axial-hydroxyl groups. Of the five group interactions, the HCl– e-OH interaction contributes a large positive value to the pair interaction Gibbs free-energy parameters of HCl with sugars, whereas the contributions of the HCl– a-OH and HCl–O interactions are very small.