Oxidation of ethylenediamine tetraacetic: acid by aromatic N-bromamines in alkaline medium with OsO₄ as catalyst: A kinetic and mechanistic study

Abstract

Kinetics of oxidation of disodium ethylenediamine acid (EDTA) by bromamine-B (BAB) and</p> bromamine-T (BAT) have been investigated at 35ᵒC in alkaline medium with OsO₄ as catalyst. The oxidation behaviour is similar in both cases and obeys the rate law, rate <em>k</em>[OX][OH^-][EDTA]⁰[RNH₂]^-x where x is a fraction, indicating retardation of rate by the reaction products benzene sulphonamide (BSA) and <em>p</em>-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.