Highly effective green oxidation of aldehydes catalysed by recyclable tungsten complex immobilized in organosilanes-modified SBA-15

Abstract A simple and eco-friendly approach for green oxidation of aldehydes has been proposed, which employed highly efficient heterogeneous catalysts tungsten-doped modified silica SBA-15 (W-SBA-15) as catalysts and H 2 O 2 as a green oxidant. W-SBA-15 were synthesized by immobilizing tungsten species on modified SBA-15 and first used in the aldehydes oxidation reaction. W-SBA-15-APTS (0.002 g, APTS, a kind of modifier) displayed an equivalent catalytic activity comparable to that of homogenous catalyst (H 2 WO 4 , 0.5 g) and maintained excellent catalytic activity over 20 cycles. The pore diameter, ca . 7.94–9.14 nm, of W-SBA-15 provides a suitable mesoscopic environment for the substrate, and the product can diffuse freely during the oxidation of glutaraldehyde (GA). Effective but different catalytic performance of W-SBA-15 for the oxidation of other aldehydes suggests the universal applicability of W-SBA-15. The possible mechanism of the oxidation state of tungsten species in W-SBA-15-APTS was proposed; tungsten species are not only attached to APTS but also incorporated into the framework of SBA-15.