Mesoporous niobium phosphate catalysts with different Fe content (Fe-NbP) were synthesized, characterized, and tested for the conversion of glucose to levulinic acid (LA) in this study. The results showed that the catalyst physicochemical properties have an important effect on glucose conversion to LA. The catalyst with larger surface area, high acid amount, appropriate acid density and ratio of Lewis acid to Brønsted acid seemed beneficial for LA production. The maximum LA yield was 62.4 mol%, which obtained from 100 % glucose conversion at 180 °C for 180 min with using 0.50 g Fe-NbP catalyst. Moreover, a simplified kinetic analysis which based on pseudo first-order model was also proposed in this study, and the results indicated that the activation energy of glucose dehydration and HMF rehydration over Fe-NbP catalyst were 65.30 and 57.49 kJ/mol, respectively, much lower than those over NbP catalyst, which probably due to the doping of Fe into NbP enhancing the catalyst Lewis acid site, and thus finally reduce the energy barrier for glucose conversion through accelerating glucose-fructose isomerization. However, catalyst with excessive Lewis acid also converted the glucose into humins. Finally, the recycling of Fe-NbP catalyst manifested that the deposition of insoluble solid on the catalyst surface were the main reasons for catalyst activity reduction, however, after simply calcination, the Fe-NbP catalyst can be reused at least for four times with the activity loss less than 12.7 %.

Fe-NbP as an effective catalyst for levulinic acid production from glucose: Characterization and performance

255th National Meeting (2018)

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