The kinetics of oxidation of gallic acid with potassium bromate in the presence of vanadiurn(V) catalyst in aqueous acid medium has been studied under varying conditions. The active species of catalyst and oxidant in the reaction were understood to be HBrO, and VO,+The autocatalysis exhibited by one of the products, i e., Br-, was attributed to complex formation between bromide and vanadiurn(V) A composite scheme and rate law were possible, some reaction constants involved in the mechanism have been evaluated. 0 1996 john Wiley & Sons Inc