The Study On The Catalytic Hydrogenation Of Biomass Platform Compounds Using Materials Derived From Nickel-based Metal Organic Frameworks(Ni-MOF)

The renewable biomass resource can efficiently replace traditional fossil energy.The transformation of biomass to value-added chemicals has been a hot spot in the field of energy and chemical engineering.It is promising to develop novel catalytic system to promote the transformation of biomass platform compounds to produce high-value added fine chemicals.The catalysts derived from metal-organic frameworks（MOFs）with large pore size,specific surface,and good stability have gotten a great interest concerning in organic catalytic field.Therefore,developing novel catalyst derived from MOFs materials for promotion the transformation of biomass platform compounds is of great scientific significance in the chemical research.In this thesis,we aimed to develop the derived Ni-based catalysts using Ni-MOF as the starting materials and investigate their promotion for the hydrogenation of biomass platform compounds-vanillin and furfural with hydrogen resource.At the same time,the possible reaction mechanism was proposed.The main work is as followings.（1）Ni-MOF([Ni（tia）·H₂O]_∞(tia^2-=5-（1H-1,2,3-triazol-1-yl）isophthalate))was synthesized using the H₃ctia ligand.This Ni-MOF material was calcined under N₂atmosphere at the temperature range of 300℃～800℃to afford Ni-MFC-X catalysts（X=300～800）.When Ni-MFC-X catalysts were applied to catalyze the hydrogenation of vanillin using H₂ as the hydrogen resource.It was found Ni-MFC-700 exhibited the highest catalytic hydrogenation activity,in which the conversion of vanillin was up to100%and the selectivity of main product 2-methoxy-4-methylphenol was up 96.5%under the optimal reaction conditions.At the same time,comparsion with the traditional supported Nickel catalysts prepared through the impregnation method,Ni-MFC-700 catalyst outperformed these supported catalysts.Furthermore,the activity and selectivity of Ni-MFC-700 catalyst kept almost unchanged even after being reused five times.Based on the results of some control experiments and the dynamic experiments,the possible mechanism of dehydroxygenation of vanillin in alcohol medium was proposed.It was found acetal and hemiacetal was formed over the solid acid.The acetal and hemiacetal was reduced to produce the intermediate（2-methoxy-4-（methoxymethyl）phenol）.The ether oxygen bond in 2-methoxy-4-（methoxymethyl）phenol was broken to produce the deoxygenated product2-methoxy-4-methylphenol.（2）Ni-MFC-X（X=300～800）catalysts were also applied to catalyze the hydrogenation of furfural.The results showed that the calcination temperature has influence on the conversion and the selectivity of products on the hydrogenation of furfural.In the case of Ni-MFC-500,a 92.5%conversion of furfural with 59.5%selectivity of furfuryl alcohol（FOL）and 30.9%selectivity of tetrahydrofurfuryl alcohol（THFOL）was attained.The aforementioned solid catalyst Ni-MFC-700provided a 91.8%conversion of furfural,in which the selectivity of FOL and selectivity of THFOL were up to 39.1%and 51.0%under similar conditions,respectively.Moreover,to optimize the catalytic reaction conditions,the influences of reaction time,hydrogen pressure and temperature were also studied in detail.Furthermore,the catalyst recycling experiments verified that they are stable on the furfural hydrogenation.Also,the as-obtained characterization data of XRD,BET,XPS,HRSEM and NH₃-TPD further illustrated that Ni-MFC-X catalyst was of high stability and recyclability in the reaction.