Different Carbon Supports Supported Gold To Catalyze 5-hydroxymethylfurfural To Produce 2,5-furandicarboxylic Acid

With the increase of fuel consumption,biomass is widely used as a green and environmentally friendly renewable resources have attracted wide attention.As the representative of biomass,5-hydroxymethylfurfural?5-HMF?has great research value and is regarded as one of the twelve biological platform molecules with the most research value.And the oxidation product of 5-HMF,2,5-furandicarboxylic?FDCA?can not only be used to synthesize polyester chemical products,it can also be used as an important part of pharmaceutical intermediates and fine chemical products.The extensive application of FDCA makes it important to find effective catalysts to promote the efficient oxidation of5-HMF to prepare FDCA.In this paper,a series of catalysts supported on porous spherical graphitized carbon?PC?were prepared by using sodium borohydride reduction method to support different contents of Au.With the increasing of Au loading,the conversion of 5-HMF did not change obviously,but the selectivity of FDCA increased.When 4wt%Au/PC was used as catalyst,nearly 100%5-HMF conversion and 60%FDCA selectivity were obtained.According to a series of characterization methods such as N₂ adsorption-desorption isotherm,XRD,SEM and XPS,the precious metals were not uniformly dispersed on the carrier.Synthesis of flake graphitized carbon?GC?,by in-situ self-growing method.GC was used as carrier and using the same reduction method of sodium borohydride to support different contents of Au,a series of catalysts xwt%Au/GC?x=0.7,1.0,1.3,2.0 and 2.7?were synthesized.A series of catalysts were tested for 5-HMF catalytic oxidation activity,in which 2.0wt%Au/GC could achieve 100%5-HMF conversion and 97%FDCA selectivity.At the same time,the catalyst has good recycling effect.A series of XRD,SEM,N₂ adsorption-desorption isotherms were carried out on the catalysts.The properties and structures of the catalysts were characterized by ICP-OES,XPS and TEM.The reasons for the different activities of different catalysts were investigated.The effects of different reaction conditions,such as reaction time,reaction temperature and reaction pressure,on the catalytic activity were investigated by 2.0wt%Au/GC.The result of activity and characterization showed that Au⁰ was the active site of the catalyst.In addition,a series of characterizations such as FTIR,TG-DTA and ESI-TOF were used to investigate the reaction pathway of 5-HMF oxidation to FDCA.