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

摘要

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 Na2SO4 resulted in decrease in rate constant value,suggesting involvement of oppositely charged species in the rate determining step.The overall stoichio-metry of the reaction has been found to be 2AO~+ + 3ClO_2~-+ 3H~+ + 6H2O = 2P + 2(CH3)2NH+OH + CH3CH2OH + 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.