Preparation Of 5-ethoxymethylfurfural From Biomass Catalyzed By Modified Molecular Sieve

5-ethoxymethylfurfural(5-ethoxymethylfurfural)is a well-known fuel and fuel additive as well as a potential transportation fuel.One-pot synthesis of EMF from agricultural wastes catalyzed by modified molecular sieves is a promising approach for efficient utilization of biomass,which has the advantages of wide source,simple process and high added value.At present,lignocellulosic biomass couldn’t achieve a moderate yield when it was directly used as raw material,so increasing the yield of EMF is an important research direction.In this paper,the conversion of fructose,glucose and other biomass sugars by modified catalyst was studied,and the conversion of monocrystalline cellulose and corn stalk powder was gradually carried out.Firstly,a single factor optimization experiment was carried out on fructose with the optimum catalyst P0.2-USY to optimize the reaction temperature,reaction time,substrate concentration and the amount of catalyst,the effects of various factors(reaction temperature,reaction time and amount of catalyst)on EMF yield were investigated,and the interaction of various factors on EMF was also investigated.Then,the single factor and kinetic experiments of the modified catalyst for the catalytic conversion of glucose to EMF were also set up and carried out.Gas chromatography-mass spectrometry(GC-MS)is used for qualitative analysis of liquidphase products prepared by modified catalyst to explore the distribution of compounds in liquid-phase products.The main conclusions are as follows:1)among the modified catalysts prepared by a series of modification methods,the modified solid acid:P0.2-USY prepared with 0.2ωt%ammonium dihydrogen phosphate as the modified material,USY as the carrier and equal volume impregnation method has the best catalytic effect on fructose in the preliminary test.The analysis and characterization of P0.2-USY showed that the modified substance P was well loaded on USY after modification,the crystallinity decreased slightly and the sintering phenomenon was slight,the specific surface area decreased,the pore volume increased and the pore diameter remained unchanged,the acid strength increased and the acid content increased obviously.2)using P0.2-USY as catalyst,single factor and response surface method were used to optimize the process conditions of one-pot synthesis of EMF from fructose.After optimization,the yield of EMF can reach 74.1 mol%at 127℃,32 min,40 g/l substrate concentration and 1.35ωt%modified catalyst dosage.The modified catalyst is reused,after a simple recovery,the catalyst is put into the next use.Each recall reduces EMF yield by approximately 15%.The liquid phase products of EMF from fructose were analyzed by GC-MS,and the possible reaction pathway was proposed by analyzing the distribution of compounds in the products.3)The reaction conditions,such as reaction temperature,reaction time,concentration of substrate and amount of catalyst,were investigated,the yield of 39.6 mol%EMF was obtained at 200℃,100 g/L substrate concentration,10 min reaction time and 1.95ωt%modified catalyst.The kinetic study on the preparation of EMF by alcoholysis of glucose shows that the activation energy of EMF is:Ea=8.732 kJ/mol,and the rate equation of EMF formation is:YEMF=YEMF,0+0.0012*[1-e-0.0174]/0.0174.The results of GC-MS analysis showed that the products mainly included EMF,EL,ethyl glucoside and furfural.The reaction route of fructose alcoholysis catalyzed by modified catalyst was proposed.4)The modified catalyst catalyzed the low EMF yield of cellulose and corn stover.The product was analyzed by GC-MS.The results showed that the cellulose alcoholysis products mainly contained EMF,EL,furfural and ethyl glucoside;The acid strength,acid content and L/B ratio of the modified catalyst are not suitable for catalyzing cellulose and corn stover to produce EMF in one pot.