Catalytic Effect Of Hydrotalcite-based Catalyst On Hydrogenation Of Furfural

The increasing energy demand have caused a series of environmental issues like depletion of fossil sources and green house effect.Biomass is regarded as a potential substitution for petroleum-based materials because it is carbon-neutral,abundant and renewable.Development of utilizing and converting biomass to useful chemicals and fuels has earned a global focus and become a hot research point over the world.Furfural is a important platform chemical derived from biomass only,products from hydrogenation of furfural like furfuyl alcohol?FOL?,2-methylfuran?2-MF?are all essential chemicals and furl additives.Traditional commercial process of catalytic hydrogenation of furufal might cause severe pollution problem originated from Cr element.Therefore,it's significant and worthy to develop eco-friendly solid catalysts.Layered double hydroxides?LDHs,also called Hydrotalcies?are a kind of versatile functional materials.In this thesis we prepared two LDHs?Cu-Fe LDH and Ni-Fe LDH?,and utilized them as precursors to synthesis hydrotalce-based catalysts through calcination and reduction process.X-ray diffraction,X-ray photoelectron spectroscopy,nitrogen temperature programmed desorption and other methods were conducted to characterize these catalysts.Results showed that unique Jahn-Teller effect caused by Cu²⁺influenced not only the structural integrity of Cu-Fe LDH,but also form a large ratio of spinel structure with greatly decrease of specicifc surface area in the derived mixed oxide?DMO?during the calcination.After reduction,Cu-Fe catalyst was achieved in the form of nano particle where Cu⁰ was supported on spinelp;while iron oxide would be co-reduced with nickel oxide to generate alloy.Then,hydrotalcite-based catalysts were in application of fufural hydrogenation under high pressure at high temperature in order to fina an optimum condtion.Copper is the active component in Cu-Fe catalytic system,and prefers to get the preliminary prduct from hydrogenation of furfural,that is to say,FOL.99.9%conversion of furfural and 90.0 yield of FOL could be attained at 200? under 2 MPa H₂ with a nine-hour mechanical stirring.The total yield of products would not increase no matter how much we boosted the reaction parameters including H₂ pressure,reaction time,temperature or so on.While thsese methods altered the distribution of products.Magnetic stirring was a feasible way to accelerate reaction rate obvisouly,but it couldn't influence the balance.Cyclic tests proved that Cu-Fe catalyst was recyclable and stable enough after several runs.Ni-Fe catalyst took a higher selectivity to 2-MF when reaction temperature was higher than 200?,along with a higher production yield.99.9%conversion of furfural and 54.9 yield of 2-MF was reached under 2 MPa H₂ at 200? for 9 h.The optimum reaction condition should be 2 MPa H₂ for 6 h when temperatue was 250?,thus yield of FOL was 4.7%and yield of 2-MFwas 31.8%.