Novel tungsten-containing mesoporous HMS material: its synthesis, characterization and catalytic application in the selective oxidation of cyclopentene to glutaraldehyde by aqueous H2O2

Tungsten-containing hexagonal mesoporous silica (HMS) has been synthesized by using dodecylamine as template at room temperature. The as-prepared novel material is very active as a catalyst for the selective oxidation of cyclopentene (CPE) to glutaraldehyde (GA) with environmentally benign hydrogen peroxide as the oxidant. Tungsten species could stably exist in the silica-based matrix of HMS up to a Si/W molar ratio of 30, as determined by X-ray diffraction (XRD), laser Raman spectroscopy, and FT-IR. Proper content of tungsten species and its high dispersion account for its high activity. Complete conversion of cyclopentene and very high yield of glutaraldehyde (∼76.3%) are obtained over the W-HMS catalyst with a Si/W molar ratio at 30. Furthermore, almost no tungsten species are leached into the reaction solution, enabling the catalyst to be employed for many reaction cycles without dramatic deactivation.