Study On Hydrogenation Of Biomass-derived Compounds Catalyzed By Supported Ru And Ni Catalysts

Environmental issues and energy crisis are the most compelling topics in recent years.As concerns about the environmental hazards and unsustainability of fossil fuels,many scientists are turning their attention to renewable energy such as biomass.The development of low-cost,high-efficiency catalytic hydrogenation catalytic materials and routes in the production of energy chemicals is an important research direction.In this paper,during the preparation of supported ruthenium and nickel nano-particles catalysts,the catalytic performance of prepared catalysts was carried on the hydrogenation upgrading of biomass-derived compounds under mild reaction conditions.X-ray diffraction,transmission electron microscopy,and Raman scattering spectroscopy were used to analyze the relationship between catalyst support and catalyst performance,and the reaction mechanism was elaborated.The main findings of this article are as follows:Using acid-activated carbon nanotubes as carrier,the average Ru particle size of Ru/CNTs,which was prepared by impregnation method,is 2.74 nm.In the reaction of green solvent water,the catalytic hydrogenation of the biomass-derived platform compound furfural to cyclopentanone were carried on mild reaction conditions?reaction temperature is 160°C,hydrogen pressure is 1 MPa,stirring speed is 500rpm?,and furfural was efficiently upgraded by 1 h,while the conversion of 4.68 mmol furfural was 99%and the selectivity of cyclopentanone was 91%.The unique conductivity of CNTs as a catalyst support which accelerates the dissociation of hydrogen into hydrogen atoms,and form hydrogen overflow phenomenon on the surface of the catalyst.Finally the hydrogen overflow improved the catalytic efficiency.The Ru/CNTs catalyst itself has an acidity,which accelerates the ionization of water to generate more H⁺,and the cyclopentanone looping reaction requires H⁺as the catalyst of intermediate compounds,so that the final yield and selectivity of cyclopentanone increased.The results showed that the special properties of the Ru/CNTs bifunctional catalyst for the catalytic hydrogenation of biomass-derived compounds for producing high value-added energy chemicals,and catalyst preparing methods have important reference significance for the future high-performance catalyst preparation.Using rice husk carbon as catalyst support,transition metal nickel as catalytic active center,the Ni/RHGC were prepared by the methods of carbothermic reduction and catalytic graphitization.Through configuring its graphitization degree and the hydrodeoxygenation reaction of vanillin to 4-methyl guaiacol,we established a relationship between catalyst support and catalytic activity.The partially graphitized catalyst has an ordered graphite structure with a partially conductive when porous rice husk carbon that can adsorb a large amount of hydrogen,and when the catalyst accelerates the dissociation of hydrogen into hydrogen atoms,the catalytic hydrodeoxygenation of the catalyst in vanillin is enabled.The reaction of upgrading vanillin to 4-methyl guaiacol showed excellent catalytic activity.Through the research of this dissertation,it is found that in the supported nano-metal catalysts,the catalytic activity is not only influenced by the nano-metal particles,but also the change of the catalyst support.This provides an effective research idea for the preparation of novel high-efficiency non-precious metal catalysts and their application in catalytic hydrogenation upgrading of biomass-derived compounds.The Ni/RHAC with high catalytic hydrodeoxygenation activity prepared by the carbothermic reduction method was applied to hydrodeoxygenation of vanillin,a bio-oil model compound.The nickel nanoparticles in the catalyst are uniformly loaded and the agglomeration phenomenon is not obvious.It is found that the catalyst is a porous adsorption catalyst with multi-stage pore structure through nitrogen adsorption characterization.By adjusting the solvent composition of decalin/water,it was found that Ni/RHAC can emulsify Pickering emulsion reaction system under mild conditions,so that hydrodeoxygenation of vanillin took place in the gas-liquid-solid of the Pickering emulsion microcapsule reactor.At the three-phase junction,the selectivity of 4-methyl guaiacol,the selectivity of target product has greatly increased.The prepared 20 wt%Ni/RHAC-500 was used in a mixed solvents?30 mL decalin and 10 m L water?and emulsified the condition,1.31 mmol vanillin was added in and mild condition?120°C,H₂ pressure=1 MPa,500 rpm?was applied,the conversion of vanillin was 95%and the selectivity of 4-methyl guaiacol was 100%after 3 h.Through the research in this paper,it has shown that the nature of the catalyst in the catalytic hydrodeoxygenation reaction emulsifies the reaction solvent into a Pickering emulsion,which reduced the influence of the additional emulsifier on the reaction and the difficulty of separation of the reaction product,obtaining good reaction results under mild conditions.