Efficient Epimerization of Glucose to Mannose over Molybdenum‐Based Catalyst in Aqueous Media

Abstract Herein, the high activity and selectivity of activated carbon‐supported molybdenum oxide catalysts (Mo/AC) in the epimerization of glucose to mannose is described. The catalysts afforded near‐equilibrium glucose conversion (29.2 %) and selectivity (94.5 %) toward mannose in the epimerization of glucose. The catalysts were characterized by X‐ray diffraction, UV‐Vis diffuse reflectance spectroscopy, and X‐ray photoelectron spectroscopy. It was found that the Mo/AC catalysts were mainly composed of highly dispersed MoO 2 and MoO 3 species. Compared to the soluble MoO 3 catalyst, Mo/AC showed higher stability and better catalytic performances in the epimerization of glucose to mannose. Further, the deactivation of Mo/AC catalysts was attributed to the leaching of molybdenum oxides. Isotope labeling experiments revealed that the deuterium atom at the C‐1 position of mannose is formed by glucose‐D2 epimerization.