Selective Hydrogenation Of 5-hydroxymethylfurfural To 2,5-dimethylfuran

5-hydroxymethylfurfural is a compound which is used widely.It can be produced by hydrolysis of renewable carbohydrates under the action of acid catalyst.It can carry out a variety of reactions to produce different products due to its functional group,such as furan-based resin,2,5-furandi acid,etc.At the same time,5-hydroxymethylfurfural has pharmaceutical activity,it also plays a role in medicine.When used as a monomer,5-hydroxymethylfurfural can be used to synthesize biodegradable polymer materials.Its derivatives can be applied as a substitute for petroleum fuel,which is an important bridge of the conversion between biomass resources and fossil fuel energy.2,5-dimethylfuran has some properties which is similar to gasoline,such as high energy density,high octane number,low volatility,and low solubility.It can be used as fuel alone or mixed with gasoline,and its performance is much better than the ethanol fuel that has been developed and used.At present,the catalysts for the hydrogenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran still have shortcomings such as low selectivity,severe reaction conditions,and low catalyst stability.In this thesis,5-hydroxymethylfurfural was used as a raw material to prepare 2,5-dimethylfuran with different catalysts.Different catalysts were prepared by adjusting the content of Mo and the pyrolysis temperature of carbon-coated Mo.After that,the series of catalysts were characterized by XRD,TEM,XPS,TG,BET and so on.The results show that the active component molybdenum in the series of catalysts is dispersed uniformly.The catalyst which was synthesized by hydrothermal contains multi-stage pore sizes.Among them,there are many micropores and large specific surface area.The screened catalyst was used in the selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran,and showed excellent catalytic performance.The conditions of the selected catalytic reaction are further optimized,including the selection of the solvent of the reaction or namely the choice of hydrogen source,temperature,time,pressure,etc.The results of a series of experiments on optimizing the conditions of the catalytic reaction show that when 5-hydroxymethylfurfural is 0.1 g,catalyst is 0.01 g,ethanol is 20 mL,nitrogen pressure is 2 MPa,reaction time is 10 h and reaction temperature is 180?,Mo(?)@C-900catalyst could make the yield of 2,5-dimethylfuran reach 91.6%.The 5-hydroxymethylfurfural was completely converted and showed the bestcatalytic performance.The results of cycle experiments showed that the Mo(?)@C-900 had good catalyst recyclability properties.The conversion of raw materials and the yield of 2,5-dimethylfuran were slightly decreased after fifth use of catalyst under the same conditions.By analyzing the XRD,XPS,FTIR characterization results of the catalyst before and after the recycling,the reason for this result may be that a small amount of carbon deposits covered and some by-products adsorbed on the surface of the catalyst during recycling.