An efficient environmentally friendly CuFe 2 O 4 /SiO 2 catalyst for vanillyl mandelic acid oxidation in water under atmospheric pressure and a mechanism study

• Published in: New journal of chemistry 2021-01, Vol.45 (2), p.982-992
• Main Authors: Mao, Haifang, Wang, Hongzhao, Meng, Tao, Wang, Chaoyang, Hu, Xiaojun, Xiao, Zuobing, Liu, Jibo
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/D0NJ04798H

With the aim of the green production of vanillin, a highly efficient environmentally friendly oxidation system was introduced to oxidize vanillyl mandelic acid (VMA) with a porous CuFe 2 O 4 /SiO 2 component nano-catalyst in aqueous solution under atmospheric pressure. The N 2 adsorption–desorption pattern indicated that CuFe 2 O 4 /SiO 2 possessed a much higher specific surface area (49.98 m 2 g −1 ) than that of CuFe 2 O 4 (5.02 m 2 g −1 ), which further indicated that the SiO 2 substrate restrained the aggregation of CuFe 2 O 4 nanoparticles. The conversion for VMA and selectivity for vanillin reached 98% and 96%, respectively, under atmospheric pressure. The excellent catalytic performance was attributed to the synergistic effect of the catalytic capacity of CuFe 2 O 4 and the adsorption capacity for the reactant of SiO 2 . 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, H 2 -TPR, XPS and 1 H NMR. More importantly, the decarboxylation was verified to proceed in basic conditions rather than in conventional acidic conditions.