Catalytic aerobic oxidation of renewable furfural to maleic anhydride and furanone derivatives with their mechanistic studies

Catalytic transformation of biomass-based furfural to value-added chemicals is an alternative route to the on-going fossil feedstock-based processes. This work describes catalytic aerobic oxidation of furfural to maleic anhydride, an important polymer starting material having a large market with H5PV2Mo10O40 and Cu(CF3SO3)2 catalysts. Under the optimized conditions, 54.0% yield of maleic anhydride can be achieved with about 7.5% yield of 5-acetoxyl-2(5H)-furanone formation. Notably, 5-acetoxyl-2(5H)-furanone is a highly value-added, biologically important intermediate that has been applied in pharmaceutical synthesis. The catalytic mechanism for furfural oxidation to maleic anhydride and 5-acetoxyl-2(5H)-furanone has been investigated in detail with identification of several key intermediates.