PdCl2-FeCl3-imidazolium ionic liquid immobilized SBA-15 for boosting heterogeneous Wacker oxidation of styrene

PdCl 2 -FeCl 3 -imidazolium ionic liquid immobilized SBA-15 (SIL-PdFe) was prepared via chloropropyltriethoxysilane grafting with the surface Si-OH and N-methyl imidazole with C-Cl bond, followed by PdCl 2 and FeCl 3 coordinating to imidazolium ring. The SIL-PdFe was used as a heterogeneous catalyst for solvent-free Wacker oxidation of styrene with H 2 O 2 oxidant, exhibiting high catalytic performance with styrene conversion of 95.4% and 87.7 % selectivity (54.2% acetophenone and 33.5% benzaldehyde). The catalyst can be easily recovered and effectively reused without a significant loss in the activity and selectivity. The quenching experiments by adding tert -butanol (TBA), 1,4-benzoquinone (p-BQ) and furfural alcohol (FA) in the reaction system were conducted to identify kind of the reactive O species produced by the catalyst activating H 2 O 2 and the reaction mechanism of the Wacker oxidation was then proposed.