| 摘要： |
One-pot conversion of xylose to 1,2-pentanediol was investigated in a dual catalyst system composed of Ru/C and niobium phosphate as hydrogenation and acid catalysts, respectively. A series of niobium phosphate catalysts well-characterized by XRD, N-2 physisorption, FT-IR, NH3-TPD, Py-IR and XPS were tested regarding the effect of their acid properties on product selectivity for the studied process. A systematic study was reported on the effect of reaction conditions. The combined yield of 21-27% to 1,2-pentanediol and its precursor 1-hydroxyl-2-pentanone was accomplished at 423 K under 3.0 Mpa hydrogen pressure in water-gamma-valerolactone/cyclohexane biphasic system. At optimized conditions, the correlation between the product yield and the surface Lewis/Bronsted ratio were analyzed. The results revealed that the lower apparent activation energy of xylose dehydration reaction catalyzed by Lewis acid site accounted for the high product selectivity for sugar intermediate and furfural hydrogenation processes, especially for the combined selectivity to 1,2-pentanediol and 1-hydroxyl2-pentanone. This study lays the grounds for further design of improved solid acid catalysts with high selectivity of 1, 2-pentanediol. |
