Catalytic conversion of carbohydrates to levulinic acid with mesoporous niobium-containing oxides

A series of niobium-containing catalysts were prepared by hydrothermal synthesis method, and characterized by NH 3 -TPD, TEM, XRD, N 2 adsorption-desorption and pyridine-adsorption FT-IR techniques. Fe-NbP (Fe-doped niobium phosphate) with higher total acid density (3.59   mmol/g) and appropriate Brønsted/Lewis acid ratio (1.32) was found to show superior activity in production of levulinic acid (LA) from glucose, and a high LA yield of 64.2% was achieved at 180   °C in 3.0   h. The effect of various reaction parameters such as temperature, time, catalyst dosage, and substrate concentration on LA production has been investigated. The catalyst can be recycled for several times without significant loss of activity.