Efficient formation of formate anion from carbon monoxide and electrogenerated hydroxide ion

As a novel and electrochemical method, formate anion is effectively formed by cathodic electrolysis of a small amount (ca. 0.5 mol l−1) of water in the presence of carbon monoxide in DMF containing a tetrabutylammonium salt. The electrogenerated hydroxide ion is shown to be nucleophilic toward CO at atmospheric pressure and room temperature. Use of deuterium oxide instead of water showed a high incorporation of D in the product formate, revealing some accompanying reaction paths such as hydrogen exchange with OD− and direct reduction of the ammonium salt.