Identification of more benign cathode materials for the electrochemical reduction of levulinic acid to valeric acid

The electrochemical production of valeric acid from the renewable bio‐based feedstock levulinic acid has the potential to replace the oxo‐process which uses fossil‐based feedstock 1‐butylene. The electrochemical reduction of the ketone functionality in levulinic acid using lead or mercury cathodes is already known for over 100 years. However, large scale electrochemical production of valeric acid might be limited due to the toxicity of these materials. In this study, we identified three additional cathode materials, cadmium, indium and zinc, which selectively and efficiently produce valeric acid. Of these materials, indium and zinc are considered more benign. More specifically, at indium there is no formation of the side product γ‐valerolactone, thus resulting in the highest selectivity towards valeric acid. For the electrochemical reduction a reaction mechanism involving formation of an organometallic compound is proposed. Furthermore, a possible processing strategy is outlined to enable continuous electrochemical production of valeric acid on large scale.