Preparation Of MOF Derived Copper-based Catalysts And Their Application In Catalytic Transfer Hydrogenation Of Furfural To Furfuryl Alcohol

The growing energy crisis and environmental pollution problems associated with excessive consumption of fossil resources have led to an urgent need to develop renewable energy for producing fuels and chemicals.Biomass,which is the only renewable carbon source on earth,is considered as an ideal substitute for traditional fossil resources.Biomass can be converted into a variety of value-added chemicals and high value-added fuels.As an important biomass derivative platform molecule,furfural(FF)is the only unsaturated and commercialized organic chemical prepared through dehydration and cyclization of hemicellulose components.It has important applications in the synthesis of high value-added fuels and chemicals.Furfuryl alcohol(FAL)is an important hydrogenation product from furfural,which is widely used in the synthesis of biofuels,resins,synthetic fibers and some fine chemicals,such as vitamin C,lysine and so on.Therefore,it is of great significance to develop efficient and stable catalysts to realize the highly selective conversion of furfural to furfuryl alcohol.The purpose of this thesis is to develop a highly active,highly selective,environmentally friendly and economical catalyst for hydrogen transfer reaction of furfural(CTH),and to characterize the catalyst and explore the active sites and reaction mechanism of the catalyst.The main research contents are as follows:(1)Cu-doped ZIFs material(Cu-ZIF-8)was prepared and used as a self-sacrificing precursor template to obtain nitrogen-doped carbon-supported copper heterogeneous catalyst(Cu/Zn@NC),which was used in the study of furfural transfer hydrogenation to furfuryl alcohol.It was found that Cu/Zn@NC-600 showed excellent catalytic performance for the CTH reaction from FF to FAL.The conversion of 100% FF for 2 h at 160 °C was 100% and the yield of FAL was 96.78%.Secondly,the factors affecting the preparation of FAL by hydrogenation of FF were studied in detail,including hydrogen donor solvent,reaction temperature,reaction time and the amount of catalyst.At the same time,Cu/Zn@NC-600 also showed good stability,and the catalytic activity did not decrease significantly in the five cycles.The analysis shows that the synergism between uniformly dispersed Cu species(Cu(I),Cu(0))and surface alkaline centers helps to improve the catalytic activity of FF transfer hydrogenation,and nitrogen-doped porous carbon helps to improve the stability of metal centers.(2)On the basis of the previous chapter,Cu and Co co-doped ZIFs materials(x Cu-y Co-ZIF-8)were prepared and used as precursor templates.Copper,cobalt and zinc modified nitrogen-doped carbon-based polymetallic catalysts(x Cu-y Co/Zn@NC)were prepared by pyrolysis in argon and used in the CTH reaction of furfural.By adjusting the pyrolysis temperature and Co-Cu ratio of the catalyst,it was found that the catalytic performance of the catalyst was the best when the molar ratio of Co to Cu was 0.5 and the pyrolysis temperature of the precursor was 600 °C.At 160 °C,the conversion of the FF for 3 h is 100% and the yield of the FAL can reach 99.7%.Under the same reaction conditions,using Cu/Zn@NC-600 as catalyst,the yield of FAL was96.78%.The results show that the addition of Co further increases the yield of FAL.In addition,the cycle experiments show that the Cu-0.5Co/Zn@NC-600 catalyst has good stability and can keep the performance stable in 5 cycles.According to the characterization analysis,the high conversion and yield of Cu-0.5Co/Zn@NC-600 are not only due to its large specific surface area,but also related to the higher dispersion of metal nanoparticles and the synergism between metal Cu,Co and surface pyridine N.And N-doped porous carbon also helps to improve the stability of the metal center.