Catalytic oxidation of carbazole using t-butyl hydroperoxide over molybdenum catalysts

Catalytic oxidation of carbazole (CAZ) was investigated using oil-soluble t-butyl hydroperoxide (TBHP) as oxidant and Mo(VI) complexes as catalyst. The influences of various factors on CAZ conversion were probed including ligand, supporter, and other metals Ni and Co involving. The results show that without the supporter, Molybdenum acetylacetonate (Mo(VI)) has higher activity than MoO3 because of its solubility in hydrocarbon. All supporters, Al2O3, weakly acidic cation-exchange resin (D113) and weakly acidic chelating cation-exchange resin (D751), can promote the activity of MoO3. Incorporation of Ni and Co metals can reduce the activity of MoO3/Al2O3. It is also found that in the presence of dibenzothiophene (DBT), TBHP/MoO3/D113 presents a higher oxidation selectivity of CAZ, while TBHP/MoO3/D751 has a similar oxidation activity to CAZ and DBT. The structure of CAZ oxidation product was speculated according to the spectrum data.