Kinetics and mechanism of oxidation reaction of lactose by N-bromophthalimide: Micelles used as a catalyst

The kinetics and mechanism of the oxidation of lactose by N-bromophthalimide in the absence and presence of cetyltrimethylammonium bromide and sodium dodecyl sulfate micelles was investigated in the presence of sulfuric acid medium. Under pseudo-first-order conditions reaction rate agreed with a first-, fractional- and negative fractional-order kinetics in N-bromophthalimide, lactose and sulfuric acid, respectively. In the presence of additives, the critical micellar concentration values were lower than those given in the literature. The catalytic role of cationic micelles was explained by the Berezin model. The anionic micelles showed slightly inhibitory effect. The influence of salts, phthalimide and mercuric acetate on the reaction rate was also studied. Using the kinetic data, the rate constant, binding constants, and corresponding activation parameters were evaluated. A possible reaction mechanism, which is based on the kinetic results and the product analysis, is proposed.