Understanding How Hβ Zeolite in Dimethoxymethane-Containing Medium Efficiently Coconverts Glucose and Xylose to Methyl Levulinate

Simultaneous utilization of lignocellulose-related glucose and xylose to produce methyl levulinate (ML), a versatile industrial commodity, is important to fully expend biomass components. We herein report a promising catalytic protocol involving the Hβ zeolite in dimethoxymethane (DMM) and methanol (MeOH) cosolvent that enables the coconversion of glucose and xylose to ML under one-pot conditions. ML yield as high as 56% with a turnover frequency (TOF) of over 3.2 h^–1 can be accomplished at 150 °C. Isomerization–dehydration of glucose/xylose represents the primary reaction path, whereas the production of glycosides through etherification constitutes the secondary reaction path. The suggested catalytic mechanism is the preferential adsorption of C–O–C and C–OH groups at different acid sites, which leads to the emergence of two distinct pathways for the conversion of glucose/xylose into ML. Hβ-25, featuring a high concentration of Lewis and Brønsted acid sites, facilitates two distinct pathways for the conversion of glucose/xylose into ML. DMM functions as a hydroxymethylation reagent in the conversion of xylose to ML and promotes the isomerization of glycosides via ether exchange reactions. This contribution devises an efficient strategy for producing ML from glucose and xylose while elucidating the reaction mechanism of a tailored monolithic catalytic system.