Selective oxidation of styrene efficiently catalyzed by spinel Mg–Cu ferrite complex oxides in water

Magnetic ferrite Mg_1−xCu_xFe₂O₄ (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0) nanocrystalline complex oxides were prepared by sol–gel auto-combustion method, and characterized by X-ray diffractometry, Fourier transform infrared spectrophotometry, Raman spectrometry, scanning electron microscopy and transmission electron microscopy. Their catalytic performances were evaluated in oxidation of styrene in water using hydrogen peroxide (30 %) as oxidant. The samples were found to be efficient catalysts for the oxidation of styrene to benzaldehyde. Especially, when Mg_0.5Cu_0.5Fe₂O₄ was used as catalyst, 21.8 % of styrene conversion and 83.9 % of selectivity for benzaldehyde were obtained at 80 °C for 9 h reaction. The catalyst can be magnetically separated easily for reuse and no obvious loss of activity was observed when reused in five consecutive runs.