Highly efficient and N-bromosuccinimide-mediated conversion of carbohydrates to 5-hydroxymethylfurfural under mild conditions

Highly efficient and selective conversion of different carbohydrates to 5-hydroxymethylfurfural (HMF) has been successfully performed with N-bromosuccinimide (NBS) as a promoter. In the presence of single NBS, a 64.2 % yield of HMF from fructose was obtained in N-methylpyrrolidone for 2 h. The effects of time, temperature and reaction media are discussed. It was concluded that the preliminary bromination of substrate could improve the generation of HMF compared to the direct dehydration process. Moreover, the HMF yield could be elevated to 79.6 and 82.3 % when FeCl₃ and SnCl₄ were used as the additives, respectively. Furthermore, the addition of CrCl₃ facilitated the conversion pathway from glucose, sucrose, inulin, or cellulose to HMF. A 57.3, 68.2, 62.4, or 6.1 % yield of HMF was, respectively, obtained in the presence of CrCl₃ and NBS under mild conditions, which will therefore generate a promising application strategy for biomass transformation.