Study On The Synthesis Of Butyl Levulinate From Biomass-based Furfuryl Alcohol Catalyzed By Solid Aci

Biomass,the only carbon-containing renewable resource,which is a potential alternative to displace non-renewable fossil resources for the production of liquid fuels and chemicals.Furfuryl alcohol is the product of the hydrogenation of furfural derived from the hydrolysis of biomass-based pentose components.It not only has widely industrial applications,but also is one of the raw material for the preparation of a variety of important industrial chemicals.Among them,levulinate esters can be obtained by reacting furfuryl alcohol with alcohol,which is a class of important biomass-based platform compounds and new energy chemicals.Acid catalysis is identified as the key point for this technology.The development of clean,efficient,low-cost catalytic process system is the inevitable trend of sustainable development of the chemical industry.Based on this,a series of innovative catalytic strategies on the upgrading of biomass-derived furfuryl alcohol to butyl levulinate were performed in this dissertation.Herein,the inexpensive and readily available metal salts,glucose-derived magnetic solid acids(Fe3O4@C-SO3H)and lignosulphonate-derived solid acids(LS-SO3H)were selected as the catalysts,respectively.The catalytic performances of these selected catalysts for the transformation of furfuryl alcohol to butyl levulinate were investigated,and the key process variables were examined to determine the optimal conditions for the synthesis of butyl levulinate.The results of metal salts catalysis showed that both alkali and alkaline earth metal chlorides did not lead effectively to the conversion of furfuryl alcohol,while several transition metal chlorides(CrCl3,FeCl3,and CuCl2)and AlCl3 exhibited catalytic activity for the synthesis of butyl levulinate.The catalytic activity for their sulfates was low.The reaction performance of the metal salts was correlated with the Br?nsted acidity of the reaction system derived from the hydrolysis/alcoholysis of cations,but was more dependent on the Lewis acidity from the metal salts.Among these investigated metal salts,CuCl2 was found to be uniquely effective,leading to the 100%conversion of furfuryl alcohol to butyl levulinate with an optimized yield of 95.1%.Moreover,CuCl2 could be recovered efficiently from the resulting reaction mixture by distillation and remained almost unchanged catalytic activity in multiple recycling runs.Then,glucose and Fe3O4 were used as carbon source and magnetic matrix of the catalyst,respectively.The Fe3O4@C-SO3H was successfully prepared by hydrothermal carbonation and sulfonated with concentrated sulfuric acid.The structure,composition and magnetic properties of the catalyst were characterized by SEM,XRD,TGA,XPS,MPMS,FT-IR,BET,and acid-base titration,respectively.The results revealed that the glucose-derived magnetic solid acid has a core-shell structure and superparamagnetism,and contains some-SO3H groups.The magnetic catalyst showed high catalytic activity toward the transformation of furfuryl alcohol in n-butanol,and the conversion was close to 100%after the reaction of 2h.The synthesis of butyl levulinate was favored with the increase of the reaction temperature,the catalyst loading and reaction time.A high yield of butyl levulinate of up to 95.2%was obtained under optimal conditions.The catalyst could be easily recovered by an external magnet and reused for three times without the significant loss of its catalytic activity.Finally,the catalyst LS-SO3H was directly prepared by the sulfonation of lignosulphonate(LS).The structure and composition of LS-SO3H were analyzed by SEM,XRD,TGA,XPS,FT-IR,BET and acid-base titration,respectively.It was found that LS-SO3H has the characteristics of loose structure,and contains plentiful-SO3H groups with high surface acid content.With LS-SO3H as the catalyst for the conversion of furfuryl alcohol,a high butyl levulinate yield of 96.3%was achieved under the optimized reaction conditions.LS-SO3H could be recovered efficiently from the resulting reaction mixture by filtration and reused in the next runs,and butyl levulinate yield declined only 2.4%after the third run.To sum up,three effective catalytic strategies for the synthesis of butyl levulinate from biomass-derived furfuryl alcohol were developed in this dissertation.The advantages of these technologies is that the catalyst or the material of catalyst prepared were cheap and easily obtained,the catalytic activity was high,and the catalysts could be easily recycled and reused.The findings of the dissertation can provide theoretical guidance and technical reference for the follow-up study and industrial scale production of biomass-derived levulinate esters.