Enhanced catalytic activity for fructose conversion on nanostructured niobium oxide after hydrothermal treatment: Effect of morphology and porous structure

Dehydration of Fructose to 5-Hydroxymethylfurfural: Effects of Acidity and Porosity of Different Catalysts in the Conversion, Selectivity, and Yield

“…The treatment between the cycles were not much elaborated, i.e., it only consisted of thoroughly washing the catalyst with deionized water and heating at 100 • C for 4 h before reinserted it in the reactor. The level of deactivation is within the observed level in another report for niobia-based catalysts for the same reaction [65], which indicates a fair stability for this catalyst.…”

Niobium phosphotungstates: excellent solid acid catalysts for the dehydration of fructose to 5-hydroxymethylfurfural under mild conditions

“…Therefore, heterogeneous catalysts that can be separated from the products by filtration have been developed for the conversion of fructose to 5-HMF, for instance solid heteropolyacid Cs 2.5 H 0.5 PW 12 O 40 , 20 sulfated zirconia, 21 Fe 3 O 4 –SBA–SO 3 H, 22 tungstated zirconia, 23 zirconium oxophosphate, 24 acidic resin, 25,26 and tin-beta zeolite, 27 metal–organic frameworks (MOFs), 28 covalent organic frameworks (COFs), 29 and nanostructured niobium oxide. 30 These catalysts are efficient and recyclable in the dehydration of fructose, and these findings have inspired further studies on heterogeneous catalysts.…”

Dehydration of Glucose to 5-Hydroxymethylfurfural Using LaOCl/Nb2O5 Catalysts in Hot Compressed Water Conditions

“…The results at lower temperatures were included in Tables 2 and 4. Thus, the catalytic evaluation was performed in a broad range of temperatures (333-473 K), evidencing that the formation of HMF from fructose or glucose is only reached at temperatures higher than 373 K. It has been reported [30] that the activation energy associated with undesirable side reactions is less (60 kJ/mol) that the related to the formation of HMF (140 kJ/mol) and consequently the HMF yield tends to increase with a higher temperature, but its value is influenced by the nature of the reaction system. Our results with LaOCl/Nb 2 O 5 demonstrated that although the dehydration step of fructose could be stimulated by noncatalytic processes (conditions of hot compressed water at 273-647 K), the presence of catalysts avoids the side reactions.…”