Aqueous Hydrogenation Of 5-hydroxymethylfurfural Catalyzed By Acid-modulated Semi-sandwich Ruthenium

In recent years,with the depletion of fossil resources,biomass chemistry has been pushed into an increasingly important position in green sustainable chemistry.The exploration of new biomass reactions and new efficient catalytic systems become an extremely important issue for biomass chemistry.In this dissertation,the half-sandwich iridium complex(Cp*Ir)was used as catalyst for the hydrogenation of 5-hydroxymethylfurfural(5-HMF).In chapter 1,some research progresses in the use of biomass and resource utilization were introduced.The unsustainability and high pollution of fossil resources.highlight the significance of reactions of biomass and bio-platform molecules.Based on the discussion of bio-platform molecules,we focused on the preparation of 5-hydroxymethylfurfural(5-HMF)and its hydrogenation progressions were also summarized.In chapter 2,the research background and hydrogenation mechanism of the catalyst half-sandwich iridium complex(Cp*Ir)are mainly introduced.Cp*Ir exhibits excellent catalytic activity for the hydrogenation or dehydrogenation of carbon dioxide,alcohols,ketone aldehydes and ethers.Meanwhile,Cp*Ir showed high acid resistance.Cp*Ir and acid co-catalyst system exhibited great development potential in the hydrogenation of furan derivatives.In chapter 3,on the basis of the first two parts,Cp*Ir co-catalyst system was further developed,and it was used in the hydrogenation of 5-HMF.By using Cp*Ir and γ-Al2O3(Lewis acid),5-HMF can be converted efficiently to 3-hydroxymethyl cyclopentanone(HCPN).In comparison with it,Cp*Ir and Br(?)nsted acid can promote conversion of 5-HMF to 1-Hydroxy-2,5-hexanedione(HHD).Moreover,mechanism proposed by our predecessors was revised and supplemented.Different from previous literature,under our catalytic system,we found that HHD condensed via Aldol reaction to produce 3-methylcyclopenten-2-ol-1-one(MCP)instead of HCPN.Instead of being an intermediate for the formation of HCPN,we believe,HHD is a product of another reaction pathway.Moverover,we studied the effect of Lewis acid and Br(?)nsted acid on the hydrogenation of furfural compounds by a series of acid characterization and other experiments.We found that Bronsted acid can promote conversion of furfural compounds to straight chain ketones,and Lewis acid can promote rearrangement of furfural compounds to cyclopentanones.