Molybdenum-based Composite Oxide Catalyzed The One-step Preparation Of 2,5-furandiformaldehyde From Fructose

The fossil resources depletion and energy consumption increased motivates researchers to find new solutions to produce fine chemicals starting from renewable feedstock.Among them,biomass energy has been paid more and more attention for it being clean and renewable.As an important organic platform compound and new energy chemical,2,5-Diformylfuran(DFF)which can be obtained from carbohydrate-based biomass dehydration and subsequently 5-hydroxymethylfurfural oxidation,is widely used in the synthesis of pharmaceuticals,polymer and furan resins.In this work,a serious of Mo-based composite oxides were synthesized by a coprecipitation method and used for one-step conversion of fructose to DFF.It was found that at the same reaction conditions Zr-Mo composite oxide(ZrxMoyOδ)and La-Mo composite oxide(LaxMoyOδ)showed better activity for the yield of DFF comparing to other molybdenum oxide complex catalysts.Therefore,the effects of La/Mo,Zr/Mo mole ratios,calcination temperature and reaction conditions on the transformation of fructose to DFF were further studied.The results showed that DFF yield of 61%was achieved over Zr1Mo2Oδ(with a Zr/Mo mole ratio of 1:2,calcined at 600℃)at 160℃ for 4 h in air.In addition,the catalyst still kept the same activity after being used for 5 times.The physicochemical properties of the ZrxMoyOδ catalysts were characterized by XRD,XPS,Raman,O2-TPD,etc.XPS analyses indicated ZrxMoyOδ included three types of oxygen species,the lattice oxygen,the surface chemisorbed oxygen and the surface hydroxyl oxygen.With the Mo/Zr atomic ratio decreasing,the surface chemisorbed oxygen and surface hydroxyl oxygen content increased.Both the two kinds of oxygens have high catalytic oxidation activity to HMF.Zr1Mo20δ(calcined at 600℃)possesses relatively the more surface active oxygen species.O2-TPD showed Zr1Mo2Oδ(calcined at 600℃)had the largest amount of desorpted oxygen in the lower temperature(around 120℃)region,both of which contribute to its highest catalytic activity.Accordingly,Zr1Mo2Oδ as an efficient and recyclable heterogeneous catalyst,as well as easily prepared and eco-friendly,has great potential for industrial production of DFF from fructose in static air.