Acetamide Electrosynthesis from CO₂ and Nitrite in Water

Area of Science:

• Electrochemistry
• Catalysis
• Green Chemistry

Background:

• Electrocatalytic CO2 reduction (CO2 RR) is key for carbon neutralization, but typically yields simple carbon products.
• Synthesizing valuable C-N chemicals from CO2 and nitrogen species remains a significant challenge.
• Co-reduction of CO2 with nitrate or nitrite to aldoxime intermediates is particularly difficult.

Purpose of the Study:

• To achieve the direct electrochemical conversion of CO2 and nitrite to acetamide.
• To investigate the mechanism of this novel C-N coupling reaction.
• To demonstrate the broader applicability of this strategy for amide synthesis.

Main Methods:

• Utilized copper catalysts and a gas diffusion electrode under alkaline conditions.
• Employed operando spectroelectrochemical characterizations to monitor the reaction.
• Performed density functional theory (DFT) calculations to elucidate the reaction pathway.

Main Results:

• Successfully synthesized acetamide from CO2 and nitrite electrochemically.
• Identified key intermediates: acetaldehyde and hydroxylamine, forming acetaldoxime.
• Demonstrated the mechanism involves nucleophilic addition, dehydration to acetonitrile, and hydrolysis to acetamide.
• Extended the method to synthesize phenylacetamide, showcasing versatility.

Conclusions:

• Established a novel electrochemical pathway for synthesizing acetamide from CO2 and nitrite.
• Elucidated the reaction mechanism involving key intermediates and reaction steps.
• Provided a new strategy for producing valuable amides from CO2 and wastewater, contributing to sustainable chemistry.