Study On Catalytic Hydrogenation Of Bio-derived 5-Hydroxymethylfurfural Into Furan Compounds

In recent decades,biomass resource has been considered as the only renewable resources that can replace fossil resources to produce liquid fuels and chemicals.Therefore the conversion of biomass derived carbohydrates into 5-hydroxymethylfural(HMF)and the further preparation of high-value furan compounds 2,5-dihydroxymethylfuran(BHMF)and 2,5-dimethylfuran(DMF)have attracted much more attention in the scientific communities.According to the current research situation and exiting problems in HMF and BHMF、DMF production,a series of studies persisted in the concept of green chemistry were carried out in this dissertation.This work describes on the situ hydrogenation reaction of bio-derived HMF,which mainly focuses on the synthesis of green,efficient,low-cost and stable catalyst system.In this thesis,carbonized bagasse supported copper and zinc catalysts(Cu、Zn/CSD)were successfully prepared using bagasse dregs as raw material by carbonization and impregnation method for conversion of HMF into BHMF.The structure of catalysts was analyzed by using various characterization methods.The effects of reaction conditions on performance of catalysts and properties of recycled catalysts were investigated.Characterization results showed that Cu、Zn particles were well dispersed throughout the CSD.The HMF conversion of 86.5% and BHMF yield of 82.5% could be obtained under the conditions of hydrogen donor in ethanol solvent,the ratio on Cu to Zn of 2:1,reaction temperature of 160 °C,reaction time of 1.5 h.Properties of recycled catalysts were excellent.After using five times,the dispersity of Cu、Zn was declined,and the product yield was decreased slightly.In order to explore the in-situ hydrogenation of HMF,Ni/MCM-41 catalyst were successfully prepared by hydrothermal and impregnation method for conversion of HMF into DMF.Characterization results showed that nickel ions were loaded on the surface of the catalyst in the form of nickel oxide before reduction.Moreover,the specific surface area,pore volume and pore size of the Ni/ MCM-41 catalyst decreased to a certain extent compared with MCM-41.The HMF conversion of 98.1% and DMF yield of 64.4% could be obtained under the conditions of hydrogen donor in methanol solvent,reaction temperature of 190 °C,reaction time of 5 h,Ni load of 10%.Properties of recycled catalysts were excellent.After using five times,the dispersity of Ni was declined,and the DMF yield was decreased slightly.In addition,Ni-MCM-41 catalyst was prepared by in-situ synthesis,and the reactivity of in-situ Ni-MCM-41 and supported Ni/MCM-41 catalyst in the hydrogenation of HMF to DMF was investigated.Characterization results showed that Ni ions had successfully entered the molecular sieve.The specific surface area,pore volume and pore size of in-situ Ni-MCM-41 catalyst were higher than supported Ni/MCM-41 catalyst.The HMF conversion of 98.5% and DMF yield of 65.1% could be obtained under the conditions of hydrogen donor in methanol solvent,reaction temperature of 190 °C,reaction time of 5 h,Ni load of 10%.And the reuse performance of in-situ Ni-MCM-41 catalyst was significantly improved.After 7 times of reuse,HMF conversion rate and DMF yield were basically unchanged.In conclusion,this study has provided an economical and safe process route for the in-situ hydrogenation of HMF into BHMF and DMF,and provided theoretical basis and technical support for the preparation of high-value-added chemicals by biomass conversion.