KINETIC AND MECHANISTIC STUDY OF ELECTRON-TRANSFER FROM L-ASCORBIC-ACID AND DIOLS TO FE(III) CHELATES IN AQUEOUS H2SO4 ACID AND MICELLAR MEDIA

A detailed kinetic study of oxidation of L-ascorbic acid and other rel ated diols has been undertaken by two types of Fe(III) chelates viz., blue complexes and Blau's yellow complexes. Application of Marcus theo ry substantiated an inner sphere electron transfer from L-ascorbic aci d (or diol) to Fe(III) chelates (Blau's yellow complexes), while an ou ter sphere mechanism was operative in the case of blue complexes. Reac tions were found to be catalysed by both anionic and cationic micelles (SDS and CTAB respectively). Catalysis was explained due to the stabi lisation of transition state due to electrostatic interactions operati ng between cationic form of Fe(III) chelates and anionic CTAB respecti vely. Mechanism of micellar path could be explained by binding model.