An Efficient Environmentally Friendly CuFe2O4/SiO2 Catalyst for Vanillyl Mandelic Acid Oxidation in Water at Atmospheric Pressure and Mechanism Study

Aimed at green production of vanillin, a high-efficient environmentally friendly oxidation system was introduced to oxidize vanillyl mandelic acid (VMA) by a porous CuFe2O4/SiO2 component nano-catalyst in aqueous solution under atmospheric pressure. The N2 adsorption-desorption pattern indicated the CuFe2O4/SiO2 possessing much higher specific surface area (49.98 m2/g) than that of CuFe2O4 (5.02 m2/g), which further indicate the SiO2 substrate restraining the aggregation of CuFe2O4 nanoparticles. The conversion for VMA and selectivity for vanillin reached to 98% and 96% respectively under atmospheric pressure. The excellent catalytic performance attributed to the synergistic effect of the catalytic capacity of CuFe2O4 and the adsorption capacity for reactant of SiO2. Simultaneously, the effect of different reaction conditions for catalyst activity and selectivity were investigated. Furthermore, the probable mechanism of VMA oxidation was investigated by in-situ ATR-FTIR, H2-TPR, XPS and 1H NMR. More importantly, the decarboxylation was verified processing at basic condition rather than conventional acidic condition.