One-pot Synthesis Of 5-Ethoxymethylfurfural From Corn Straw

5-Ethoxymethylfurfural(EMF)is an important chemical intermediate and diesel additive,which is recognized as a potential alternative fuel.The preparation of 5-Ethoxymethylfurfural from waste biomass by one pot process has many advantages,such as wide source of raw materials and simple process.It is a potential way of biomass resource utilization.At present,there are few reports on the direct alcoholysis of biomass to 5-ethoxymethylfurfural,which is the key and difficult issues facing this subject to increase the yield of 5-ethoxymethylfurfural and green of the production process.In this paper,different catalysts were used to catalyze the alcoholysis of corn stalk to produce 5-ethoxymethylfurfural with or without co-solvent.The super low liquid acid(0.1wt%H2SO4),solid acid(USY)and their mixture catalytic systems were used to prepare 5-ethoxymethylfurfural from corn stalk in one pot process.The main conclusions are as follows:1.The EMF was prepared in one-pot alcoholysis of corn stalk catalyzed by ultra-low liquid acid(0.1wt% H2SO4),solid acid(USY)and mixed catalyst were studied.The effects of reaction time,reaction temperature and substrate concentration on the yield of EMF were investigated,the results are as follows:1)When ultra-low liquid acid(0.1wt% H2SO4)was used as catalyst,the optimum reaction time was 120 min,the reaction temperature was 190 ?,the concentration of straw was 20g/L and the highest EMF yield was 14.5%;When using solid acid(USY)as catalyst,the optimal reaction time was 150 min,the reaction temperature was 180? and the concentration of straw was 15g/L,the yield of EMF reached 6.4%;When 0.1wt% H2SO4 and USY were used as mixed catalysts,the optimal reaction time was 150 min,the reaction temperature was 190? and the concentration of corn stalks was 15g/L.At this time,the yield of EMF reached 21.1%.2)The yield of EMF was basically unchanged after 5 times of reutilization of USY,and the USY was characterized by FTIR,When mixed acid was used as a catalyst,the introduction of ultra low liquid acid(0.1wt%H2SO4)did not affect the molecular structure of USY,and the activity of USY could be recovered after the reaction was calcined..3)The liquid products were analyzed by GC-MS under three kinds of catalysts,the possible reaction paths for the alcoholysis of corn straw to EMF were proposed on this basis.2.The solid acid USY was used as the catalyst,and the EMF production was studied by one pot method in ethanol and co solvent system.The results were as follows:1)When tetrahydrofuran,dimethyl sulfoxide,cyclohexane and n-hexane are used as co-solvents,tetrahydrofuran can effectively increase the yield of EMF.2)In the single factor experiment,the effect of reaction time,reaction temperature,substrate concentration,USY content and kind in the co solvent system on the yield of EMF was investigated.The fixed substrate concentration was 20g/L,and the reaction conditions were optimized by the 4 factor 3 level response surface experiment method,combined with the experimental and practical operation of reaction kinetics,the process conditions were adjusted to: The reaction temperature was 150?,the reaction time was 1h,USY(0.3)was 1%,tetrahydrofuran: ethanol volume ratio was 3:2.At this time,the average yield of EMF was 21.6%.3)After the reaction of USY after the burning treatment,repeated use of 5 times,the yield of EMF basically unchanged,and FTIR characterization,it is found that in the ethanol / tetrahydrofuran system the addition of THF did not affect the molecular structure of USY,does not affect the repeated use of solid acid USY molecular sieve.4)The liquid products were analyzed by GC-MS in the co-solvent system,and the possible reaction path of 5-ethoxymethylfurfural was obtained by using the solid acid USY in the co-solvent system.