Catalytic and electrocatalytic oxidation of aniline to nitrobenzene over vanadium silicate molecular sieves: VS-1 usingt-butyl hydroperoxide (TBHP) as oxidant

A comparison of the results of catalytic and electrocatalytic oxidation of aniline using VS-1 in the presence of H2O2 and TBHP indicates remarkable differences in conversion and selectivity. VS-1 catalyzes the oxidation of aniline selectively to nitrobenzene (73%) in the presence oft-butyl hydroperoxide (TBHP), while azoxybenzene (95.2%) is formed selectively when H2O2 is used. Cyclic voltammetric studies show a three-step oxidation of aniline to nitrobenzene in H2O2 but in the presence of TBHP only one step is observed. Electrocatalytic oxidation of aniline to nitrobenzene occurs at a potential 700 mV less than that corresponding to H2O2 as oxidant along with a selectivity of 91.8%. The enhancement of electrocatalytic rate is attributed to the stabilization of electron deficient transition state