Study On Catalytic Formation Of 5-Hydroxymethylfurfural From Fructose By Solid Acid Catalyst

Among many biomass energy sources,5-hydroxymethylfurfural?5-HMF?is considered as arepresentativebiomass-basedplatformcompound,5-HMFcansynthesize2,5-dimethylfuran and various important high calorific biomass fuels.In this dissertation,a series of solid acid catalysts with good catalytic activity were prepared for the dehydration of fructose to 5-HMF.The main research contents of the paper are as follows:?1?Fe₃O₄@nSiO₂@mSiO₂ was synthesized by layer-by-layer assembly and PWA was used as the active component.Solid acid catalyst Fe₃O₄@nSiO₂@mSiO₂-PWA was prepared by impregnation method,It was used to catalyze the dehydration of fructose to prepare5-HMF,and the catalytic activity of the catalyst was investigated.The catalyst was characterized by infrared spectroscopy?FT-IR?,low temperature nitrogen adsorption?BET?,transmission electron microscopy?TEM?and X-ray powder diffraction?XRD?.The characterization results show that the mesoporous SiO₂ was successfully wrapped around the magnetic core Fe₃O₄ by the method of layer assembly,and the active components were highly dispersed on the support.The effects of the loading of the active component,the reaction time,the reaction temperature,the concentration of the substrate and the amount of the catalyst on the yield of the reaction were investigated.0.1g of fructose was reacted in 10ml of DMSO under the catalyst of 0.1g of 28%loading and reacted at 140 degrees for 75 minutes.The yield of 5-HMF after the reaction was 82.6%.The catalyst can be easily recovered by magnet attraction,but 5-HMF yield drops to 44.6%after 5 repetitions.?2?MWNTs-Fe₃O₄ was synthesized by simple impregnation calcination and p-TSA was used as the active component.Solid acid catalystp-TSA/MWNTs-Fe₃O₄ prepared by impregnation method,It was used to catalyze the dehydration of fructose to prepare 5-HMF,and the catalytic activity of the catalyst was investigated.The catalyst was characterized by infrared spectroscopy?FT-IR?,low temperature nitrogen adsorption?BET?,X-ray powder diffraction?XRD?,hermogravimetric analysis?TG?and elemental analysis.The characterization results show that the active component is uniformly supported on the carrier.The acidity of the catalyst was characterized.The results showed that the acidity of the catalyst was mainly derived from the active component p-TSA.The effects of the loading of the active component,the reaction time,the reaction temperature,the concentration of the substrate and the amount of the catalyst on the yield of the reaction were investigated.Fructose dosage 0.5g,15.1%loading amount of catalyst 0.15g,10ml DMSO as reaction solvent,reaction temperature is 170^oC reaction 75min,The yield of 5-HMF measured after the reaction was93.3%.The catalyst can be easily recovered by magnet attraction,and 5-HMF yield drops to85%after 5 repetitions.?3?Using p-TSA as active component and metal-organic framework MIL-100?Fe?as carrier,the solid acid catalyst p-TSA/MIL-100?Fe?was prepared by one-step method.TIt was used to catalyze the dehydration of fructose to prepare 5-HMF,and the catalytic activity of the catalyst was investigated.The catalyst was characterized by infrared spectroscopy?FT-IR?,low temperature nitrogen adsorption?BET?,Scanning electron microscope?SEM?and X-ray powder diffraction?XRD?and hermogravimetric analysis?TG?and elemental analysis.The characterization results show that the one-step synthesis catalyst possesses the framework structure of MIL-100?Fe?,and the active components are highly dispersed on the support.The acidity of the catalyst was characterized.The results showed that the acidity of the catalyst was mainly derived from the active component p-TSA.he effects of the loading of the active component,the reaction time,the reaction temperature,the concentration of the substrate and the amount of the catalyst on the yield of the reaction were investigated.Fructose dosage 0.5g,15.5%loading amount of catalyst 0.15 g,10 ml DMSO as solvent,reaction at a reaction temperature of 180^oC for 75 min.The yield of 5-HMF measured after the reaction was 96.3%.The catalyst can be easily recovered by magnet attraction,but 5-HMF yield drops to 46.2%after 5 repetitions.The p-TSA/MIL-100?Fe?catalyst synthesized by the one-step method was calcined in a tube furnace at 180^o C for 6 hours to prepare partially-carbonized p-TSA/MIL-100?C?catalyst.The yield of 5-HMF measured after the reaction was 89.2%.The catalyst can be easily recovered by magnet attraction,and 5-HMF yield drops to 82.3%after 5 repetitions.