Direct Synthesis of Methyl Esters from Methanol–Ethanol over Cu/meso-SiO2 Catalysts

Direct upgrading of renewable methanol and ethanol into value-added esters is an attractive yet challenging strategy for sustainable oxygenate synthesis. Herein, we report Cu/meso-SiO2 catalysts for the one-step and nonoxidative synthesis of methyl formate, methyl acetate, and methyl propionate from methanol/ethanol mixtures. Among the catalysts examined, 15%Cu/meso-SiO2 showed the best performance at 250 °C and 2 MPa, affording a total methyl ester selectivity of 90.2% with an overall yield of 63.4%. Combined structural and surface analyses reveal that the superior activity arises from the synergy between highly dispersed Cu species and balanced acid–base sites. The structure–activity correlations indicate that Cu0 promotes alcohol dehydrogenation, whereas Cu+–O–Si related acid–base sites facilitate intermediate condensation and hemiacetal dehydrogenation. This work provides an atom-economical route for the direct conversion of low-carbon alcohols into multiple methyl esters in a single step.