Selective Oxidation Of 5-hydroxymethylfurfural Into 2,5-diformylfuran Over Manganese Based Composite Metal Catalysts

The excessive dependence of the industrial society on fossil fuels such as coal,oil and natural gas,and the serious environmental pollution caused by the use of fossil fuels have aroused people's great attention to the development and utilization of biomass platform compounds.As a representative product of biomass platform,5-HMF is an important bridge connecting basic biomass raw materials with high value-added products.The DFF obtained from oxidation of 5-HMF can be widely used as drug intermediates,synthetic organic conductors and other macromolecular materials,which has extremely high industrial application value.In this paper,two kinds of Mn matrix composite metal catalysts were designed and developed including spinel CoMn2O4 hollow spheres and MnCO3/Fe2O3 to solve the problem of high cost of noble metal catalyst and low activity of non-noble metal catalysts in 5-HMF oxidation reaction system.The formation mechanism of the catalysts was investigated by a series of characterization methods,and the catalytic activity of the catalysts was evaluated.The spinel CoMn2O4 hollow spheres were prepared by solvent thermal method,where uniform cobalt-manganese glycerate spheres as the precursor were self-assembled and converted into hollow spheres by calcination.Body-centered tetragonal and face-centered cubic spinel structures of CoMn2O4 hollow spheres can be tuned by different Co/Mn molar ratios,the synergistic effect between Co and Mn species in the binary oxides by the formation of heteronuclear cluster complexes CoMn2O4,which affects and promotes the electron-transfer process,results in significant improvement in catalyst performance.Finally,41%conversion rate of 5-HMF and 100%selectivity of DFF are obtained.MnCO3/Fe2O3 nanocatalyst with high catalytic activity was prepared by using the steric hindrance of ionic liquid on the surface of nanocatalyst and the effect of ?-? stacking between imidazolium-rings to inhibit the growth process.MnCO3/Fe2O3 nanocatalyst shows the obvious effect of doping between MnCO3 and Fe2O3 crystal lattice,caused more lattice defects and distortion,which is advantageous to the electron transfer and oxidation reduction reaction cycle.