Phosphorylated mesoporous carbons （PMCs） were investigated as catalysts in the dehydration of fructose to hydroxymethylfurfural （HMF）. The acidic PMCs show better selectivity to HMF compared to sulfonated carbon c...Phosphorylated mesoporous carbons （PMCs） were investigated as catalysts in the dehydration of fructose to hydroxymethylfurfural （HMF）. The acidic PMCs show better selectivity to HMF compared to sulfonated carbon catalyst （SC） despite lower activity. The concentration of P-O groups on the PMC was correlated with the activity/selectivity of the catalysts; the higher the P-O concentration, the higher the activity. However, the higher the P-O content, the lower the selectivity to HME Indeed, a lower concentration of the P-O groups minimized the degradation of HMF to levulinic acid and the formation of by-products, such as humines. Stability tests showed that these systems deactivate due to the formation of humines and water insoluble by-products derived from the dehydration of fructose which blocked the catalytically active sites.展开更多
In this research, the influence of several factors such as reaction time, catalyst weight, temperature and different solvents on dehydration reaction of fructose and glucose to 5-hydroxymethylfurfural（HMF） was surve...In this research, the influence of several factors such as reaction time, catalyst weight, temperature and different solvents on dehydration reaction of fructose and glucose to 5-hydroxymethylfurfural（HMF） was surveyed. Nanosphere Al-KCC-1 silica with fibrous morphology was manufactured and used as proficient and recyclable catalyst for this reaction. SEM, TEM, BET, XRD, EDX, elemental mapping, ICP and FT-IR spectroscopy methods were applied for characterization of the Al-KCC-1（molar ratio Si/Al = 5, 40） catalysts. 162℃ and 1 h are the best conditions for the fructose dehydration. Under this situation HMF yield and selectivity are 92.9% and 94.5% respectively and fructose conversion is 98.4%. Also 170℃ and 2 h are the best conditions for the glucose dehydration. In this situation HMF yield and selectivity are 39.0% and39.9% respectively and glucose conversion is 97.8%.展开更多
To study the effect of adjacent hydroxyl to the active sites, several acid catalysts, i.e. substituted benzoic acids with adjacent carboxyl are employed in the fructose dehydration to 5-hydroxymethylfurfural(HMF).Expe...To study the effect of adjacent hydroxyl to the active sites, several acid catalysts, i.e. substituted benzoic acids with adjacent carboxyl are employed in the fructose dehydration to 5-hydroxymethylfurfural(HMF).Experimental results reveal that Br?nsted acid sites with adjacent carboxyl present higher catalytic ability than isolated ones. Computational results suggest that the adjacent sites lead to co-interaction on fructose, corresponding more stable transition state and faster HMF formation rate. Based on the enhancement from the adjacent sites, a novel ordered mesoporous carbon(OMC) full of carboxyls in surface is prepared and turns out to be an effective solid catalyst for HMF production from fructose derived from biomass.展开更多
基金supported by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle,LLC, for the U. S. Department of Energy (GMV). TEM studies were performed through Oak Ridge National Laboratory’s Center for Nanophase Materials Science (CNMS) which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U. S. Department of Energy
文摘Phosphorylated mesoporous carbons （PMCs） were investigated as catalysts in the dehydration of fructose to hydroxymethylfurfural （HMF）. The acidic PMCs show better selectivity to HMF compared to sulfonated carbon catalyst （SC） despite lower activity. The concentration of P-O groups on the PMC was correlated with the activity/selectivity of the catalysts; the higher the P-O concentration, the higher the activity. However, the higher the P-O content, the lower the selectivity to HME Indeed, a lower concentration of the P-O groups minimized the degradation of HMF to levulinic acid and the formation of by-products, such as humines. Stability tests showed that these systems deactivate due to the formation of humines and water insoluble by-products derived from the dehydration of fructose which blocked the catalytically active sites.
基金supported by the Isfahan University of Technology(Iran)
文摘In this research, the influence of several factors such as reaction time, catalyst weight, temperature and different solvents on dehydration reaction of fructose and glucose to 5-hydroxymethylfurfural（HMF） was surveyed. Nanosphere Al-KCC-1 silica with fibrous morphology was manufactured and used as proficient and recyclable catalyst for this reaction. SEM, TEM, BET, XRD, EDX, elemental mapping, ICP and FT-IR spectroscopy methods were applied for characterization of the Al-KCC-1（molar ratio Si/Al = 5, 40） catalysts. 162℃ and 1 h are the best conditions for the fructose dehydration. Under this situation HMF yield and selectivity are 92.9% and 94.5% respectively and fructose conversion is 98.4%. Also 170℃ and 2 h are the best conditions for the glucose dehydration. In this situation HMF yield and selectivity are 39.0% and39.9% respectively and glucose conversion is 97.8%.
基金supported by the Natural Science Foundation of Jiangsu Province (BK20151380)NSF of China (21103087 and 21872067)supported by the Fundamental Research Funds for the Central Universities (020514380116)。
文摘To study the effect of adjacent hydroxyl to the active sites, several acid catalysts, i.e. substituted benzoic acids with adjacent carboxyl are employed in the fructose dehydration to 5-hydroxymethylfurfural(HMF).Experimental results reveal that Br?nsted acid sites with adjacent carboxyl present higher catalytic ability than isolated ones. Computational results suggest that the adjacent sites lead to co-interaction on fructose, corresponding more stable transition state and faster HMF formation rate. Based on the enhancement from the adjacent sites, a novel ordered mesoporous carbon(OMC) full of carboxyls in surface is prepared and turns out to be an effective solid catalyst for HMF production from fructose derived from biomass.
