Abstract
The kinetics of the redox reaction between colloidal manganese dioxide and L-tryptophan in TX-100 micellar medium was analysed by using visible spectrophotometery. The rate of the reaction decreased with increase in concentration of TX-100 not only above, but also even below the critical micelle concentration (CMC). The reaction followed first order with respect to [MnO2], but fractional order with respect to [HClO4]. The first order kinetics with respect to [L-tryptophan] at low concentrations shifted to zero order at higher concentrations. A mechanism in agreement with the observed kinetic results was proposed and discussed. Different activation parameters (E-a, Delta H*, Delta S*, and Delta G*) were evaluated by using the Arrhenius and Eyring equations.