Designation Of Heterogeneous Heteropolyacid Catalysts In The Catalytic Synthesis Of Conversion Of Biomass Into Furfural And ?-valerolactone

It is urgent to find out alternative and renewable energies to solvethe energy crisis and environmental issues.Biomass is considered as the best carbon-based renewable energy source alternative to fossil fuels.Furfural and?-valerolactone are very important platform compounds from biomass,which are widely used in the manufacture of high-value chemicals.This paper focused on the characteristic of adjustable acidity and oxidizability of polyoxometalates?POMs?.Heterogeneous POMs catalysts were applied in the efficient and selective conversion of biomass into furfural and?-valerolactone.The details were as follows:?1?Using equal volume impregnation method,different amounts of phosphotungstic acid(H₃PW₁₂O₄₀,abbreviated as PW₁₂)was loaded on ZSM-5zeoliteto synthesize a series of supportedxPW₁₂/ZSM-5?x=10%,20%,30%,40%,50%?.Catalysts were characterized by XRD,FT-IR,³¹P MAS NMR,SEM&EDX,BET,and NH₃-TPD.Catalytic performances were investigated in one-pot converting biomass?xylose,xylan,hemicellulose,and corn stalk?into furfural.Different factors were explored on the yield and selectivity of furfural in the experiments,such as the effect of different PW₁₂2 loadings,catalyst amount,reaction temperature,reaction time,and the amount ofLiBr.The results showed that the yields of 10%PW₁₂/ZSM-5converting xylose and xylan into furfural were 73.31%and 75.09%,respectivity and the selectivity was over 75%.LiBr improved the yield and selectivity of furfural.The loading of PW₁₂and the distribution of acid sites were important for catalytic activity.PW₁₂/ZSM-5 achieved the promising utilization in biomass conversion with high selectivity,high yield and easy separation.?2?A series of different acidity and oxidative POMs catalystsRuPMoVhave been developed by replacing the Keggin-type vanadium-substituted heteropolyacids H₄PMo₁₁VO₄₀?V1?,H₅PMo₁₀V₂O₄₀?V2?,and H₆PMo₉V₃O₄₀?V3?with theRu³⁺metal ion.Catalysts were characterized by XRD,FT-IR,SEM&EDX,XPS,NH₃-TPD and et al.Catalytic activity of RuPMoV were investigated in converting levulinic acid?LA?and cellulose into?-valerolactone?GVL?in formic acid/water?FA/H₂O?system.Factors such as the concentration of formic acid,reaction temperature,reaction time,and the amount of catalyst on the yield and selectivity of GVL were investigated.The reaction kinetics from LA to GVL was also studied.Results indicated that for Ru_5/3PMo₁₀V₂O₄₀,the conversion of LA was up to 98.10%,and the yield and selectivity of GVL were 97.14%and 99.02%,respectively because of the properties of the strong acidity and oxidability,The reaction kinetics showed that the reaction was a first-order reaction with an activation energy of 45.02kJ/mol.Acidity had a greater impact on the catalytic activity of cellulose to GVL.Ru_1/3H₃PMo₁₁VO₄₀has the best catalytic activity with the conversion of 87.76%,the GVL yield of44.34%and theselectivity of 50.52%.