Preparation Of Functionalized Ionic Liquids And Their Conversion Of Sugars To 5-hydroxymethylfurfural

With the consumption of fossil resources, it caused widely concern that preparing new platform small molecules from renewable biomass resources especially cellulose biomass. 5-Hydroxymethylfurfural(5-HMF) is an important platform small molecule, mainly generated from fructose, glucose and cellulose. This paper prepared a series of functionalized ionic liquids and studied their catalytic effect of convert sugar to 5-HMF.(1) In this paper, modified imidazole ionic liquid catalyst was prepared from Lanthanum nitrate, 1-methyl imidazole chloroacetic acid salt and alcohol metal compounds(isopropyl alcohol aluminum, normal propyl alcohol zirconium and isopropyl alcohol titanium). In order to increase the catalytic activity of the catalyst,we took Cerium nitrate, Aluminum nitrate and Chromium nitrate to prepare the catalysts. The catalysts were characterized by FT-IR, TGA, NH3-TPD, SEM, TEM and XRD etc, which indicated the catalysts were successfully synthesized. They were used in catalytic conversion of fructose, glucose and cellulose to 5-HMF research. We adopt single factor optimization method to explore the effect of reaction time, reaction temperature, catalyst dosage, solvent species and substrate concentration, etc, and we also studied the reusability of the catalyst. The best reaction conditions of catalytic transformation of fructose were 50 mg fructose, 10 mg Cr-IL-Ti as catalyst, 1.0 g DMSO as solvent, 140 oC, 2 h, the yield of 5-HMF could reach 30.4%. The catalyst might be reused for 5 times and the catalytic activity was basically unchanged. The best reaction conditions of catalytic transformation of glucose were 50 mg glucose, 20 mg La-IL-Al as catalyst, 1.0 g DMSO as solvent, 140 oC, 3 h, the yield of 5-HMF could reach 23.3%. The catalyst could be reused for 4 times and the catalytic activity was basically unchanged. The best reaction conditions of catalytic transformation of cellulose were 50 mg cellulose, 30 mg La-IL-Al as catalyst, 0.8 g [BMIM]Cl and 0.2g DMSO as solvent, 160 oC, 6 h, the yield of 5-HMF could reach 11.2%.(2) We prepared amino acid ionic liquid catalysts L-Ala Cl, L-Val Cl, L-Glu Cl and L-Gly Cl. The catalysts were characterized by melting point test, 1H NMR, 13 CNMR and FT-IR, which indicated that the catalysts were successfully synthesized.They were employed in catalytic fructose and glucose to prepare 5-HMF research. We adopt single factor optimization method to explore the effect of each factor and we also studied the reusability of the catalyst. The best reaction conditions of catalytic transformation of fructose were 50 mg fructose, 15 mg L-Glu Cl as catalyst, 1.0 g DMSO as solvent, 120 oC, 15 min, the yield of 5-HMF could reach 83.7%. The catalyst could be reused for 4 times and the catalytic activity was basically unchanged.(3) In order to enhance 5-HMF yield from glucose, we introduced Lewis acid into amino acid ionic liquid catalytic system. The effect of each factor was implemented. The best reaction conditions of catalytic transformation of glucose were50 mg glucose, 15 mg L-Glu Cl and Sn Cl4(30 wt.%) as catalyst, 1.0 g DMSO/[BMIM]Cl(w/w=8:2) as solvent, 120 oC, 5 h, the yield of 5-HMF could reach44.5%.