SULFATE FREE RADICALS –A KINETIC APPROACH FOR OXIDATION OF L-ASCORBIC ACID IN AQUEOUS ACID MEDIUM
N. K. Soni, Riya Sailani, Anita Meena, Vinita K. Gupta, C. L. Khandelwal, P. D. Sharma.
The kinetics of oxidation of L-ascorbic acid in absence and presence of silver(I) as catalyst has been studied in aqueous acid medium. The
stoichiometry corresponds to the reaction as represented by eqn: S2O8
2- + C6H8O6 → 2SO4
2- + C6H6O6 + 2H+
. The order with respect to
ascorbic acid is unity in uncatalyzed reaction where as it is zero order in silver (I) catalyzed reaction. The reaction mechanism has been
suggested in both the conditions delineating the role of sulfate radical ion.
Key words: sulfate free radicals; ascorbic acid; peroxodisulfate; radical kinetics; acid aqueous medium