A High-Performance Base-Metal Approach for the Oxidative Esterification of 5-Hydroxymethylfurfural
Exploring high-performance base-metal approaches for the sustainable production of chemicals from biomass is presently attracting immense interest and is truly important to promote their industrialized application. Herein, CoOx-N/C and α-MnO2 were combined as a base-metal catalyst that can achieve high yields of furan-2,5-dimethylcarboxylate (FDMC, 95.6 %) for the catalytic oxidative esterification of 5-hydroxymethylfurfural (HMF) without basic additive. The reaction proceeds through fast conversion of HMF to diformylfuran (DFF) with α-MnO2 and subsequent transformation of DFF to FDMC by CoOx-N/C. Quantitative X-ray photoelectron spectroscopy (XPS) analysis and density functional theory (DFT) calculations indicated that the pyridinic-N present in doped carbon could behave as a Lewis base to promote the abstraction of hydrogen for the oxidative esterification reaction. Consequently, CoOx-N/C is a high performance catalyst for the synthesis of FDMC from DFF in a neutral medium.