Glucose Catalyzed Alcoholysis To Prepare Methyl Levulinate

The continuous development of society and economy benefit from the over-increasing exploitation of non-renewable resources,which also led to environment pollution.Therefore,exploiting clean renewable energy is already in the extremely urgency.Biomass resources,the most abundant renewable resources in the world,is a kind ofbiomass as the carrier of green energy.Hence,it is desirable to converte biomass resources into a variety of energy chemicals and industrial chemicals for the environmental protection.Levulinate ester has received extensive attention because of its good reactive activity and industrial application value.Currently,there are three pathways for the synthesis of levulinate ester from biomass conversion:conversion of biomass to levulinate esters via levulinic acid,conversion of biomass to levulinate esters via alcoholysis of furfuryl alcohol,and direct conversion of biomass to levulinate esters.Among these,the direct conversion of biomass to levulinate esters is the most promising pathway.However,the development of high efficiency catalyst is the most important part of the process.In this thesis,using the homemade solid acid as the catalyst,the glucose as basic material,we studied the conversion of glucose in methanol to methyl levulinate,the main results are as follows:?1?This thesis presents the hydrothermal synthesis of Al-MCM-41 molecular with different Al/Si ratio,and the characterization by powder X-ray diffraction,Fourier transform infrared spectroscopy,N2 adsorption,and NH3 temperature-programmed desorption,as well as by pyridine adsorption FT-IR spectra.It was found that the Al-MCM-41 with Al/Si ratio of 3 has large specific surface and the excellent catalytic performancedue to a combination of a large amount of acidic sites,together with the well balance of Lewis and Br???nsted acid sites on the catalyst.The yield of methyl levulinate as high as 38.0%was obtained when reacting 0.3 g glucose,0.15 g catalyst and 24 g methanol at 220 ? under 2 MPa N2 for 6 h.Upon recycling of the catalyst,3 Al-MCM-41 catalyst shows good cycle performance.?2?SO₄^2-/Al₂O₃-SnO₂ with different sulfuric acid concentration and different Al/Sn is prepared via co-condensation method.And they were employed for the catalytic conversion of glucose to methyl levulinate in methanol medium.Among these catalysts used,the SO₄^2-/Al₂O₃-SnO₂ with 0.2 M H2SO4 and Al/Sn ratio of 5 showed remarkably high yield of methyl levulinate of 37.2%.It was found that 0.2 SO₄^2-/Al₂O₃-SnO₂-5 has a large amount of acidic sites,together with the well balance of Lewis and Brensted acid sites on the catalyst.The catalyst can restore effective acid sites through washing and calcination approach at 450 ?.And the activity of the catalyst remained stable after 4 times of reaction.It was also verified that the deposition of carbon species in pores and surface of catalyst was the main reason for catalyst deactivation through the cycle experiment.