Immobilized Ionic Liquid As Efficent Catalyst For Biomass Conversion To 5-hydroxymethyl Furfural

Biomass is the only renewable resources containing carbon in nature,and it is an excellent substitute for fossil fuels such as coal and petroleum.Catalytic conversion of biomass to high grade fuels and value-added platform chemicals is conducive to improving China's energy structure,protecting energy and social security.It is also of great significance on promoting China's sustainable development.Based on the advantages of ionic liquid catalysts in catalytic activity and the excellent catalyst recovery performance of immobilized materials,this paper constructed a series of immobilized ionic liquids-isopropanol catalytic system to research the progress of dehydration of fructose to preparation of 5-HMF.The relationship between the structure of catalyst and the loading of catalysts and its catalytic activity was discussed.The effects of temperature and other process factors on the catalytic conversion of fructose were investigated.The research results showed that the prepared immobilized ionic liquids had embodied a high activity in the process of catalytic conversion of fructose to 5-HMF,and the catalyst and solvent in this system are both easy to recovery and have a good performance of recycling.The specific works are as follows:(1)Carboxylic acid based immobilized ionic liquids has been synthesized and its catalytic performance of the conversion of fructose to HMF was investigated.The effects of different reaction conditions on catalytic performance were studied systematically.The best reaction conditions are as follows: catalyst: 70%IL-COOH-Cl/SBA-15,catalyst dosage: 50 mg,solvent volume: 10 mL,reaction temperature and time: 100 oC and 120 min.The synthesis step of the composite materials is firstly the synthesis of 1-acetate-3-(triethoxysily propyl)imidazolium chloride(IL-COOH-Cl)by the organic method,then grafted it on SBA-15 to synthesize different loading immobilized ionic liquids(X%IL-COOH-Cl/SBA-15).TGA,NMR,BET and other characterization experiments of synthetic immobilized ionic liquids were carried out.(2)In order to further improve the yield of HMF,1-propylene sulfonic-3-(triethoxysily propyl)imidazolium hydrogen sulfate(IL-HSO3-HSO4)was synthesized,and it was grafted on SBA-15 to synthesized different capacity immobilized ionic liquids(X%%IL-SO3H-HSO4/SBA-15),then TGA,NMR,FR-IR,BET and other characterization experiments have been applied to the synthetic composite materials.The catalytic performance of the materials has been researched.Research results showed that the conversion rate of fructose was 100% and the yield of HMF was 78.75% under the optimal reaction conditions(catalyst: 70%IL-SO3H-HSO4/SBA-15,mcata.= 25 mg,Vsol.= 10 mL,reaction temperature and time: 100 oC and 90 min.).The activity was not significantly reduced after six recycling experiments.