Preparation Of5-hydroxymethylfurfural From Carbohydrates Catalyzed By Lewis Acids In Ionic Liquid

5-hydroxymethylfurfural （HMF） is a potentially important platform chemical thatconnects renewable biomass feedstock with the future industrial production ofbiofuels and chemical intermediates. Compared with traditional starting materialfructose, glucose and cellulose can be obtained from the most abundant renewablelignocellulosic biomass, and they can be used as ideal model compunds to investigatethe mechanism of preparation HMF from carbohydrates. So it is meaningful toinvestigate the reaction process of producing HMF from glucose and cellulose.In this study, we systematically studied the catalitic performance of different Lewisacids on the yield of HMF from glucose and cellulose in1-butyl-3-methylimidazolium chloride （[BMIM]Cl） solvent, and the catalysts which showedgood catalitic performance for glucose and microcrystalline cellulose conversion werealso investigated for lignocellulose conversion. The reaction process toward rapidproduction of HMF and furfural from lignocellulosic biomass feedstock-acacia woodchips was investigated in detail at170oC²00oC, using Lewis acid catalysts in[BMIM]Cl solvent. Several key factors including Lewis acid salts species,hydrochloric acid （HCl） concentration, reaction temperature and the stability of ionicliquid in the reaction system etc. were studied in order to optimize the yields of HMFand furfural from lignocellulose feedstock.The results shows that the catalytic performance is not so coordinated with theacidity of Lewis acid salts. The catalitic activity for strong Lewis acid AlCl₃and FeCl3is lower than weaker Lewis acid salts CrCl₃·6H₂O, CrCl₃, CrCl₂and SnCl₄·5H₂O, thelow activity for selective conversion of glucose to fructose is the main reason. And it’sindicated that the production of HMF from lignocellulosic biomass is greatlyaccelerated under a higher temperature than that reported in literature for celluloseconversion. HMF and furfural yields of54.58%and14.84%, respectively, areachieved at190oC in4min under optimized reaction conditions with CrCl₃·6H₂Ocatalyst, and there is no obvious decline of HMF yield after reuse two times. Thishigh-temperature reaction process is rapid and cost-effective for the industrialproduction of HMF and furfural with no need for pretreatment of lignocellulosebiomass. The [BMIM]Cl solvent and the CrCl3·6H2O catalyst are experimentally verified to be stable under the reaction conditions for multiple reuse.