Catalytic conversion of carbohydrates to 5-hydroxymethylfurfural promoted by metal halides

The promotion effect of alkali metal halides toward the AlCl3-catalyzed conversion of glucose to 5-hydroxymethylfurfural (HMF) was investigated. The results show that NaF inhibited the reaction. However, NaI and NaBr promoted the reaction significantly, and the promotion effect of NaI was more obvious than that of NaBr. In N,N-dimethylacetamide (DMAC), when NaI was used as an additive for the AlCl3-catalyzed conversion of glucose at 130 °C for 15 min, glucose conversion increased from 71% to 86%, and the HMF yield increased from 36% to 62%. The AlCl3-NaI-DMAC system could also be used for the catalytic conversion of other carbohydrates such as fructose, mannose, sucrose, maltose, cellobiose, and inulin to HMF. When sucrose was used as the feedstock, a 63% HMF yield was achieved.

Graphical AbstractNaI can significantly promote the AlCl3-catalyzed conversion of glucose to 5-hydroxymethylfurfural (HMF). The AlCl3-NaI-DMAC system can also be used for the catalytic conversion of other carbohydrates such as fructose, mannose, sucrose, maltose, cellobiose, and inulin to HMF.Figure optionsDownload full-size imageDownload as PowerPoint slide