Mechanism of oxidation of aldoses by chloramine T

Abstract

The kinetics of the oxidation of four aldoses, xylose, arabinose, mannose, and galactose have been investigated in highly alkaline media. The reactions show a brief initial induction period after which first-order dependence on both chloramine T, and the aldose follows. The order in hydroxide ions has been found to be second but shows a slight decrease at high concentration of alkali. The energies of activation have been obtained as 22–23·8 and 28–30 kcal mol^–1 for the oxidation of pentoses and hexoses respectively. A mechanism involving a termolecular rate-determining reaction among hypochlorite ion, hydroxide ion, and the anion derived from the β-anomer of aldose is suggested. The oxidation rates follow the order xylose > arabinose > galactose > mannose.