Electrochemical Hydrogenation of Aliphatic Aldehydes and Acids using Pentlandite Catalysts

Electrochemical hydrogenations are considered a sustainable alternative to classical thermocatalytic processes prevalent in industrial conversions. Using a base metal sulfide of the pentlandite class, the hydrogenation of glutaraldehyde and propionic acid was investigated. While propionic acid could not be converted, glutaraldehyde was conveniently transformed to the semi‐ and fully hydrogenated products 5‐hydroxypentanal and 1,5‐pentanediol with a partial current density of up to 34 mA cm−2 and a Faraday efficiency of 34 %. Crucial factors for a stable and efficient reaction were found to be the use of an appropriate buffer, avoidance of low pH and the used membrane type. The reaction was implemented into a zero‐gap cell reaching a single pass conversion of up to 22 %, underlining the potential for future application. The electrochemical hydrogenation of biomass‐derived dialdehydes enables a sustainable route towards green α,ω‐diols. Specifically, for glutaraldehyde, the influence of cell components and electrolyte on the efficiency of the reaction is exemplified and continuous operation in a scalable zero‐gap electrolyzer demonstrated.