KINETIC AND MECHANISTIC STUDY OF RUTHENIUM(III) CATALYZED AND UNCATALYZED OXIDATION OF OXALIC-ACID BY ACID BROMATE

Acid bromate-oxalic acid reaction in the presence of mercury(II)-a bro mide ion scavenger, is slow and exhibits first order each in [oxidant] , [oxalic acid] and [mineral acid]. The: proposed mechanism assumes a slow rate determining formation of an oxalyl-bromate ester, followed b y the fast decomposition to products. The same reaction in the presenc e of Ru(III) is accelerated and exhibits fractional order each in [sub strate], [catalyst] and [acid] and first order in [bromate]. The Propo sed mechanism for catalysed reaction assumes a complex formation betwe en oxalic acid and Ru(III), which subsequently undergoes decarboxylati on after interacting with bromate. The mechanisms, for over all, catal ysed and uncatalysed reactions are critically examined and values of r ate constants of each reaction are evaluated. Activation parameters fo r all the reactions are also evaluated and discussed.