Kinetic study of oxidation of galactose by N-bromo phthalimide in the presence of cationic micelle in acidic medium

摘要

The kinetics of micellar catalyzed oxidation of galactose by N-bromophthalimide was studied in the presence of acidic medium at 308 K. The oxidation reaction exhibits first-order kinetics with respect to oxidant (N-bromophthalimide), fractional order with respect to substrate (galactose) and positive fractional order with respect to HClO_4 on the rate of reaction. The rate of the reaction increased with decreasing the dielectric constant of the medium. With a progressive increase in the concentration of CTAB, the rate of reaction increased and after reaching peak k_(obs), decreased at higher concentrations of CTAB. There catalytic roles are best explained by Berezin’s model. The influence of salts on the reaction rate was also studied. The various activation parameters have been calculated. The rate constant and binding constant with the surfactant have also been evaluated. A suitable mechanism consistent with the experimental findings has been proposed.