KINETICS AND MECHANISM OF THE OXIDATION OF L-ASCORBIC-ACID BY THE ,N'-ETHYLENEBIS(SALICYLIDENEIMINATO)MANGANESE(III) COMPLEX IN AQUEOUS-SOLUTION

The kinetics of oxidation of L-ascorbic acid by the N,N'-ethylenebis(s alicylideneiminato) manganese(III) complex have been studied over the 4.5-9.3 pH range. An intermediate ascorbate complex was formed which h ad an inhibiting effect on the rate of the redox reaction. The rapid f ormation of this intermediate was followed using the stopped-flow tech nique, whereas its slow decomposition was monitored using a convention al spectrophotometer. The formation of this intermediate was strongly pH dependent. Addition of sodium perchlorate and sodium dodecyl sulpha te (anionic surfactant) affected the reaction rate. A probable mechani sm comprising both the intermediate formation and the overall redox re action is discussed.