Catalytic and electrocatalytic oxidation of toluene over vanadium aluminophosphate molecular sieves: VAPO-5 using H₂O₂ and <i>t- </i>butyl hydroperoxide as oxidant

2325-2328A comparison of the results of catalytic and electrocatalytic oxidation of toluene using VAPO-5 in the presence of H2O2 and TBHP indicates remarkable differences in conversion and selectivity.VAPO-5 catalyzes the oxidation of toluene selectively to benzoic acid (70%) in the presence of t-butyl hydroperoxide (TBHP), while benzaldehyde (48%) is formed selectively when H2O2 is used. Cyclic voltammetric studies show a three step oxidation of toluene to oxidized product in TBHP and two step oxidation of toluene in H2O2. Electrocatalytic oxidation of toluene to oxidized products occurs at a potential 800 mV less than that corresponding to H2O2 as oxidant. The enhancement of electrocatalytic rate is attributed to the stabilization of electron deficient transition state