Production of C3-C6 Acetate Esters via CO Electroreduction in a Membrane Electrode Assembly Cell

Electrocatalytic carbon monoxide reduction has been previously reported to yield a range of carbonaceous products including alcohols, hydrocarbons and carboxylic acids. However, esters, an important family of organic compounds, have not been formed. Herein, we report the electrosynthesis of C-3 to C-6 acetate esters (H3C-(C=O)-O-R) from carbon monoxide using copper catalysts in a membrane electrode assembly cell. Ethyl acetate and propyl acetate could be produced with an unprecedented total Faradaic efficiency (FE) of similar to 22 % and with a current density of up to -55 mA cm(-2), alongside minor quantities of methyl acetate and butyl acetate. The esters are produced via the addition reaction of ethenone (H2C=C=O) and alcohols produced during CO reduction. We show that the near water-free reaction conditions and the high local pH play key roles in the formation of the esters.

Automated summary

This article reports the electrosynthesis of C-3 to C-6 acetate esters from carbon monoxide using copper catalysts in a membrane electrode assembly cell. Ethyl acetate and propyl acetate could be produced with high efficiency and current density, while minor quantities of methyl acetate and butyl acetate were also formed. The reaction conditions and pH play crucial roles in the formation of the esters.