KINETIC AND MECHANISTIC STUDY OF BR(V) OXIDATION OF GLYCOLIC ACID-CATALYZED BY AQUOCHLORORUTHENIUM(III) COMPLEX AT DIFFERENT ACID STRENGTHS- EVALUATION OF INDIVIDUAL RATE CONSTANTS AND THERMODYNAMIC PARAMETERS

Oxidation of glycolic acid (GA) by bromate in the presence of perchlor ic acid at moderate and low concentrations is catalysed by aquochloror uthenium(III) complex. The reactions at moderate and low acid strength s exhibit different kinetic behaviour on account of existence of catal yst in different forms. In moderate acid solutions, the mechanism prop osed involves the oxidation of Ru(III) to Ru(V) by the oxidant which i n turn forms a reversible complex with substrate in the ratio of 1:2. The decomposition of the complex thus formed, into products is the slo w rate determining step. At lower [acid], the mechanism is visualised as the formation of reversible complex between GA and catalyst precedi ng the formation of an intermediate with the oxidant in a slow-step. T he decomposition of the intermediate into products is assumed to be th e fast step. The rate constants involved in all individual steps of th e reactions are evaluated along with their activation parameters and d iscussed.