Selective Oxidation of Furfural to 2(5H)-Furanone and Maleic Acid over CuMoO4

Green synthesis of high-value furanone derivatives and C-4 organic acids from renewable biomass is a promising yet challenging route. Herein, we report a suitable heterogeneous and recoverable bimetallic CuMoO4 catalyst for the selective oxidation of furfural to 2(5H)-furanone and maleic acid (MAc). The resulting CuMoO4 manifested excellent catalytic performance with a high furfural conversion of 99%, giving a 2(5H)-furanone yield of up to 66% or a MAc yield of over 74% by regulating the reaction conditions. The synergy of Cu and Mo species in CuMoO4 boosted the outstanding catalytic efficiency through the Mo6+-Mo5+-Mo4+ redox facilitated by the redox of Cu+/Cu2+. More importantly, the Mo species in CuMoO4 played a key role in activating the aldehyde group in furfural to facilitate hydrogen abstraction from the aldehyde group by CuMoO4 and the active SO4 center dot- radical, which was from peroxymonosulfate (PMS). This work presents a sustainable process for the fabrication of bio-based polymer precursors and offers a bifunctional catalysis strategy for efficient oxidation.