Catalytic effect of pre-micellar aggregates on oxidative degradation of acridine orange by acidic chlorite

Abstract

Study of catalytic effect of pre-micellar aggregates on oxidative degradation of acridine orange by acidic chlorite has been investigated. With excess of other reactants, both un-catalyzed and catalyzed reactions follow pseudo-first order kinetics with respect to [AO + ]. The un-catalyzed reaction follows fractional order kinetics in oxidant. Role of acid has been found to be complex. Increase in ionic strength by the addition of Na 2 SO 4 resulted in decrease in rate constant value, suggesting involvement of oppositely charged species in the rate determining step. The overall stoichiometry of the reaction has been found to be 2AO+ 3ClO 2 - + 3H + + 6H 2 O = 2P + 2(CH 3 ) 2 NH+OH + CH 3 CH 2 OH + 3HCl P=7-dimethylaminoquinoline-2,3-dicarboxylic acid. The lowest catalytic concentration for C 16 TAB is found to be 1.0 x 10 -5 mol dm- 3 which is much less than it's CMC. The pre-micellar catalytic kinetic data has been rationalized in the light of various prominent models like Menger-Porteny's, Piszkiewicz's and Raghavan-Shrinivasan's to understand the catalyzed mechanistic aspect of surfactant catalysis. The positive cooperative index (n = 1.15) has also been computed. On the basis of observed results and product characterization most plausible mechanisms for un-catalyzed and catalyzed reactions have been envisaged.