Immobilization of tungsten chelate complexes on functionalized mesoporous silica SBA-15 as heterogeneous catalysts for oxidation of cyclopentene

An efficient hybrid mesoporous heterogeneous catalyst system was synthesized via covalently grafting tungsten chelate complex W- N , N ( N , N  = (3-triethoxysilylpropyl) [3-(2-pyridyl)-1-pyrazolyl] acetamide, N,N -chelating ligand) in organic moieties (diphenyldichlorosilane, DPHS)-functionalized mesoporous silica SBA-15 or pure SBA-15. Characterization of synthesized materials via N 2 sorption, XRD, TEM, UV–Vis DRS, 29 Si MAS NMR, element analysis, and FT-IR indicated that W- N , N was successfully anchored and highly dispersed in the mesochannels of SBA-15 and the mesostructure of SBA-15 was maintained during the grafting course. The synthesized hybrid catalysts were highly active and authentically heterogeneous in triphasic oxidation reaction of cyclopentene (CPE) with H 2 O 2 . W, N - N immobilized on functionalized SBA-15 with DPHS moieties (W- N , N -DPHS-SBA-15) showed better catalytic properties (activity and stability) than its unmodified counterpart W- N , N -SBA-15 catalyst. Besides, possible catalytic reaction route for CPE oxidation with H 2 O 2 over W- N , N -DPHS-SBA-15 catalyst was proposed. The amphiphilic mesochannels of W- N , N -DPHS-SBA-15 provided suitable accommodation for both hydrophilic H 2 O 2 and hydrophobic CPE molecules and acted as nanoreactors for CPE/H 2 O 2 /solid triphase reaction.