Oxidative reaction between perphenazine and peroxyacetic acid [Part 1. Kinetic study]

The oxidation of perphenazine to perphenazine sulphoxide by peroxyacetic acid was kinetically studied utilizing first derivative UV-spectrophotometry and a simple iodometric procedure. The first-derivative UV-spectrophotometric procedure indicates that the reaction with respect to perphenazine is most probably zero-orer at the initial stage with a rate constant [k0] of magnitude 5.62x10-8 mol L-1S-1. Based on the titrimetric procedure in which 0.01 N Na2S2O3 was employed the reaction with respect to peroxyacetic acid is most probably second order initially having a rate constant [k2] equal to 0.05805 L mol-1 S-1. the disparity between the orders with respect to concentration [i.e.nc] and time [i.e.n1] for peroxyacetic acid was highlighted