Sustainable electrochemical synthesis of dry formaldehyde from anhydrous methanol

Formaldehyde is a platform chemical used for example in the syntheses of polymers and complex molecules. The current formaldehyde synthesis relies on high temperatures to produce an aqueous solution, which requires energy intensive water removal for its use as a C1 building block. In this work, we report the successful electrification of the direct synthesis of anhydrous formaldehyde from methanol. Sustainable formaldehyde is produced with Faraday efficiencies of 80% in an H-cell and even up to 90% and elevated current densities in a scaled-up flow reactor. Comparing different reaction conditions, we furthermore show an impact of the current density and electrolyte concentration on the prevalent reaction mechanism. Our study demonstrates a selective and efficient electrochemical synthesis of dry formaldehyde at relevant scales, paving the way for green industrial production processes. Dry formaldehyde was electrochemically produced from methanol at ambient conditions. Faraday efficiencies of up to 90% were achieved and the reaction was successfully scaled-up to a flow cell to approach industrially relevant operation conditions.