Catalytic conversion of glucose into 5-hydroxymethylfurfural using double catalysts in ionic liquid

An efficient process for the conversion of glucose into 5-hydroxymethylfurfural (HMF) using chromium (III) chloride (CrCl ₃·6H ₂O) and boric acid (B(OH) ₃) as double catalysts in ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) was developed. The effects of various reaction parameters on HMF yields were also investigated. The results showed that the highest HMF yield of 78.8% was achieved at 120°C for only 30min. A small amount of water in this reaction system had little effect on HMF yields. After the extraction of HMF, [BMIM]Cl and CrCl ₃·6H ₂O/B(OH) ₃ could be reused and demonstrated stable activity after five successive runs. Furthermore, tetraethyl ammonium chloride (TEAC) was found to be favorable to HMF formation and was also used as an effective solvent for the conversion of glucose into HMF.