Tungsten doped mesoporous SBA-16 as novel heterogeneous catalysts for oxidation of cyclopentene to glutaric acid

Novel heterogeneous tungsten species in mesoporous silica SBA-16 catalysts based on ship-in-a-bottle methodology are originally reported for oxidizing cyclopentene (CPE) to glutaric acid (GAC) using hydrogen peroxide (H 2 O 2 ). For all W-SBA-16 catalysts, isolated tungsten species and octahedrally coordinated tungsten oxide species are observed while WO 3 crystallites are detected for the W-SBA-16 catalysts with Si/ W = 5, 10, and 20. The specific surface areas and the corresponding total pore volumes decrease significantly as increasing amounts of tungsten incorporated into the pores of SBA-16. Using tungsten-substituted mesoporous SBA-16 heterogeneous catalysts, high yield of GAC (55%) is achieved with low tungsten loading (for Si/W = 30, ~13 wt%) for oxidation of CPE. The W-SBA-16 catalysts with Si/W = 30 can be reused five times without dramatic deactivation. In fact, low catalytic activity provided by bulk WO 3 implies that the highly distributed tungsten species in SBA-16 and the steric confinement effect of SBA-16 are key elements for the outstanding catalytic performance.