Iron-based metalloporphyrins as efficient catalysts for aerobic oxidation of biomass derived furfural into maleic acid

A series of porphyrin type catalysts with the metal active sites of Fe were prepared and investigated in aerobic oxidation of biomass-based furfural to maleic acid (MAD) in aqueous phase. The catalytic performance of meso-tetrakis(4-bromophenyl)porphyrin iron (HI) chloride (FeT(p-Br)PPCl) immobilized on different supports was evaluated. It was interesting to find that the catalytic activity varied with the supports and followed the trend: FeT(p-Br)PPCl/SBA-15 > FeT(p-Br)PPCl/meso-ZSM-5 > FeT(p-Br)PPCVMCM-41. The effect of reaction conditions were discussed in detail over FeT(p-Br)PPCl/SBA-15 catalyst, and 56.1% yield and 73.8% selectivity of MAD were obtained from renewable furfural under the optimal conditions. Moreover, the FeT(p-Br)PPCl/SBA-15 catalyst could be reused five times without a significant decrease of activity in recycling examinations.