Study On High Efficient Catalysts For Selective Hydrogenation Of Furfural

With the increasing depletion of fossil energy and environmental problems,The development and utilization of biomass energy has been the focus of research in recent years.Furfural,as an important platform for biomass production,has entered the scale of industrialization,however,the unstable nature and low utilization rate make it possible to transform it into a more effective downstream product with high added value.In the numerous reaction chains,the hydrodeoxygenation?HDO?route is of high research value to produce 2-methylfuran product.2-methylfuran is an important chemical raw material for the production of furan compounds,pentanediol,as well as an important intermediate in the pharmaceutical field,and can also be used as a good fuel additive.However,there are few studies on the preparation of 2-methyl furan by liquid phase hydrogenation and thus it is of great significance to develop a catalyst with good catalytic activity and stability.Firstly,spinel ferrites NiFe₂O₄ supported Ru catalysts have been prepared via a simple sol-gel route and applied for converting biomass-derived furfural to 2-methylfuran.The as-prepared catalysts were characterized by thermogravimetric analysis?TG?,N₂ adsorption-desorption,X-ray diffraction?XRD?,scanning electronic microscopy?SEM?,X-ray photoelectron spectroscopy?XPS?,and H₂-temperature programmed reduction?H₂-TPR?.Results showed that the catalysts had well-dispersed Ru active sites and large surface area for calcination temperature ranging from 300 to 500 ?.When the calcination temperature was 300 ?,the specific surface area was up to 354 m2/g,however,the higher specific surface area was still maintained at 500 ??93 m2/g?.With the increase of the calcination temperature,the crystal structure of the nickel iron spinel becomes more and more perfect and the particle size become larger.A significantly enhanced activity and increased 2-methylfuran yield have been achieved in this study.The effects of reaction temperature,reaction time,Ru loading and calcination temperature on the reaction were carefully investigated.Under mild conditions: 180 ? and 2.1 MPa N₂,2-propanol as hydrogen source,the conversion of furfural exceeded 97% and 2-methylfuran yield was up to 83% over the catalyst containing 8 wt% Ru.Secendly,we investigated the catalytic activity by changing the proportion of Ni/Fe with loaded and non loaded ruthenium respectively,and the reason for the high activity and stability of the catalyst were investigated by comparative experiments and cyclic experiments respectively.The experimental results show that there are obvious differences in the phase of Ni/Fe catalysts with different ratios after reduction.Furthermore,the proportion of Ni or Fe in FeNi alloy has a great influence on the reaction and the synergistic effect between Ru species and FeNi alloy is the main reason for obtaining high catalytic activity.The results showed that the ruthenium catalyst supported by Ni/Fe=0.5:1 had the best stability,and the catalytic activity was not changed obviously after five cycles.According to the XRD test,it is shown that the presence of kamacite phase has a positive effect on the stability of the catalyst.The characterization of TEM,ICP and XPS before and after the reaction showed that the catalyst had good stability in two aspects of structural stability and chemical stability.Finally,the reaction of Cu doped Ni Fe spinel to furfural aqueous phase hydrogenation rearrangement for preparation of cyclopentanone?CPO?was studied.The experimental results show that the catalyst has high catalytic activity and the doping of Cu can effectively control the excessive hydrogenation of CPO,and the best result is obtained when the doping amount is 25%.Under the condition of 160 ?,4 MPa,1 h,FFA conversion was 100%,CPO yield was 65%.According to the XPS analysis,it was found that the doping of Cu can lead to the lattice change of spinel,and the interaction between Cu and FeNi alloy is the main reason for the selective conversion of furfural.