THERMODYNAMICS OF THE HOMOGENEOUS OXIDATION OF L-ASCORBIC-ACID BY MOLECULAR-OXYGEN CATALYZED BY RUTHENIUM ION AND RUTHENIUM CHELATES

The homogeneous oxidation of ascorbic acid by molecular oxygen catalzed by RuCl//2(H//2O)//4** plus , Ru(III)-IMDA and Ru(III)-EDTA has been investigated in the temperature range 278-308 K, mu equals 0. 1 M KNO//3. The rate of oxidation of ascorbic acid in the presence of RuCl//2(H//2O)//4** plus was found to be first order in RuCl//2(H//2O)//4** plus and ascorbate concentrations and one-half order in molecular oxygen concentration. Based on the kinetic parameters, a mu -peroxoruthenium(IV)-ascorbate complex was suggested as an active intermediate in the RuCl//2(H//2O)//4** plus -catalyzed oxidation of ascorbic acid by molecular oxygen.