KINETICS AND MECHANISM OF OXIDATION OF CARBOHYDRAZIDE BY CHLORAMINE-T AND BROMAMINE-T IN ACID AND BUFFERED AQUEOUS-MEDIA

Kinetics of oxidation of carbohydrazide (CH) by chloramine-T (CAT) and bromanmine-T (BAT) have been investigated in aqueous medium under varying conditions. The kinetics of reactions in aqueous perchloric acid show first order in [oxidant] and fractional order in [CH]. But the rate dependences in [H+] are concentration dependent. At low [HClO4], oxidation by both CAT and BAT shows inverse fractional order in [H+], and at [HClO4] > 0.005 mol dm-3, the rate shows zero to fractional order In buffered media, the reactions are first order in [oxidant] and fractional to first order in [CH], but are independent of pH. Mechanisms consistent with the observed results have been considered and the related rate laws deduced. Coefficients of the rate-limiting steps and the corresponding activation parameters are also calculated.