Abstract
We present here the results of an investigation aimed at identifying catalysts for the dehydration of glucose and xylose to 5-hydroxymethylfurfural (I-IMF) and furfural in a diphasic reaction system, and the subsequent conversion of HMF and furfural to 2,5-dimethylfuran (DMF) and 2-methyl furan (MF) was also investigated. For the dehydration of glucose and xylose mixture, a series of SO42-/ZrO2-TiO2 solid acid catalysts were prepared by precipitation and impregnation method. Effects of various reaction parameters and catalyst reuse cycle toward the reaction performance were studied. Experimental results indicated that the product yield could reach 30.9 mol % (for HMF) and 54.3 mol % (for furfural) under the optimal experimental conditions. The SO42-/ZrO2-TiO2 catalyst is recoverable from the resulting product mixture and reused multiple times after calcination without any substantial change on the HMF and furfural yield. Furthermore, effects of various hydrogenation parameters of HMF and furfural in n-butanol promoted by carbon-supported ruthenium (Ru/C) were discussed, and the highest yield could reach 60.3 mol % (for DMF) and 61.9 mol % (for MF) under the optimal experimental conditions by starting with HMF and furfural in pure n-butanol, but the target products of DMF and MF could not be detected when directly used by the separated organic phase as solvent and substrate. However, the DMF and MF yield could reach 32.7 and 17.5 mol %, respectively, when the separated organic phase undergoes a further purification, which indicated that the purification of the organic phase is a key step for the further hydrogenation of HMF and furfural to DMF and MF.