Iron(III) reduction by D-galacturonic acid. Part I. Influence of Copper(II) complexes formation

The addition of copper(II) ions to the system iron(III)-D-galacturonic acid strongly enhances the yield of the reduction of iron(III) to iron(II). In a copper(II)-iron(III)-D-galacturonic acid system with initial quantities in 4:1:5 relative ratios, iron reduction occurs almost quantitatively. The results found are explained by the formation of stable copper(II)-D-galacturonate complexes that leads to opening of the sugar molecule ring, with consequent formation of reducing aldehydic functional groups.