Oxidative Esterification of 5-Hydroxymethylfurfural with an N-doped Carbon-supported CoCu Bimetallic Catalyst

Graphical No base needed : N-doped carbon-supported CoCu bimetallic catalyst with enhanced O 2 activation ability and basicity is demonstrated as an effective catalyst for the oxidative esterification of 5-hydroxymethylfurfural. The introduction of Cu significantly enhances the catalytic activity, resulting in a high furan-2,5-dimethylcarboxylate yield and an impressive formation rate, paving the way for the efficient and green synthesis of sustainable bio-based polymer monomers. The direct fabrication of furan-2,5-dimethylcarboxylate (FDMC), a promising renewable monomer, from biomass-derived 5-hydroxymethylfurfural (HMF) is a cutting-edge process. In this contribution, an elaborately designed N-doped carbon-supported CoCu bimetallic catalyst (Co x Cu y -NC; x / y= 9:1, 7:3, 4:6, which represents the designed molar ratio of Co and Cu in the catalyst), which could offer a desirable FDMC yield of 95 % under mild and base-free conditions (Co 7 Cu 3 -NC, 2 bar O 2 , 80 °C, 4 h) is described for the oxidative esterification of HMF. Notably, an FDMC formation rate of 6.1 mol FDMC mol Co −1 h −1 was achieved over Co 7 Cu 3 -NC, which represents the highest catalytic efficiency so far among Co-based catalytic systems. It has been demonstrated that Cu-doping in Co 7 Cu 3 -NC catalyst brings about more active sites (Co-N x species) with stronger molecular oxygen activation ability. The increase of surface N content of Co 7 Cu 3 -NC also improves basicity of the catalyst, which favors the hydrogen abstraction process during the HMF oxidative esterification reaction. These findings may pave an efficient and green way for the synthesis of sustainable bio-based polymer monomers.