OXIDATION OF ETHYLENEDIAMINE TETRAACETIC ACID BY AROMATIC N-BROMAMINES IN ALKALINE-MEDIUM WITH OSO4 AS CATALYST - A KINETIC AND MECHANISTIC STUDY

Kinetics of oxidation of disodium ethylenediamine-tetraacetic acid (EDTA) by bromamine-B (BAB) and bromamine-T (BAT) have been investigated at 35-degrees-C in alkaline medium with OsO4 as catalyst. The oxidation behaviour is similar in both cases and obeys the rate law, rate = k[OX][OH-][EDTA]0[RNH2]-2 where x is a fraction, indicating retardation of rate by the reaction products,benzene sulphonamide (BSA) and p-toluene sulphonamide (PTS). The rate is unaffected by added halide ions and variation in ionic strength. Activation parameters for the reaction have been computed from the Arrhenius plots and are compared with those of uncatalysed reaction. The mechanism assumes the formation of a complex between the active oxidant species, NaOBr, and the catalyst which interacts with the substrate in a fast step.