Highly selective oxidation of styrene to benzaldehyde over Fe3O4 using H2O2 aqueous solution as oxidant

Fe3O4 was prepared by an alternative method using the dropwise addition of FeCl3 and FeSO4 precursor solutions into a NaOH solution, as proved by XRD, TEM and magnetic measurements. The Fe3O4 material was confirmed to be well-crystallized magnetite with an average size of about 21.5 nm and stronger superparamagnetic with a saturation magnetization of 57.04 emu/g and it was found to be an effective catalyst for liquid-phase oxidation of styrene to benzaldehyde (BzH) with H2O2 as oxidant, getting ca. 100% selectivity to BzH with 40.4% conversion of styrene. This catalyst can be easily recovered by a simple magnetic separation and effectively reused. However, the reaction mechanism was confirmed by in situ DRIFTS spectra analysis and according to literature reports.