Synthesis of Benzoic Acids from Electrochemically Reduced CO₂ Using Heterogeneous Catalysts

A method for the synthesis of benzoic acids from aryl iodides using two of the most abundant and sustainable feedstocks, carbon dioxide (CO₂) and water, is disclosed. Central to this method is an effective and selective electrochemical reduction of CO₂ (eCO₂RR) to CO, which mitigates unwanted dehalogenation reactions occurring when H₂ is produced via the hydrogen evolution reaction (HER). In a 3-compartment set-up, CO₂ was reduced to CO electrochemically by using a surface-modified silver electrode in aqueous electrolyte. The ex-situ generated CO further underwent hydroxycarbonylation of aryl iodides by MOF-supported palladium catalyst in excellent yields at room temperature. The method avoids the direct handling of hazardous CO gas and gives a wide range of benzoic acid derivatives. Both components of the tandem system can be recycled for several consecutive runs while keeping a high catalytic activity.