Closing the Gap: Towards a Fully Continuous and Self‐Regulated Kolbe Electrosynthesis
Patrick Drögemüller, Tobias Stobbe, Uwe Schröder
Abstract
Abstract In this article, we address the transition of the Kolbe electrolysis of valeric acid (VA) to n ‐octane as an exemplary electrosynthesis process from a batch reaction to a continuous, self‐regulated process. Based on a systematic assessment of chemical boundary conditions and sustainability aspects, we propose a continuous electrosynthesis including a simple product separation and electrolyte recirculation, as well as an online‐pH‐controlled VA feeding. We demonstrate how essential performance parameters such as product selectivity ( S ) and coulombic efficiency (CE) are significantly improved by the transition from batch to a continuous process. Thus, the continuous and pH‐controlled electrolysis of a 1 M valeric acid, starting pH 6.0, allowed a constantly high selectivity of around 47 % and an average Coulomb efficiency about 52 % throughout the entire experimental duration. Under otherwise identical conditions, the conventional batch operation suffered from lower and strongly decreasing performance values ( S n‐octane , 60min =10.4 %, S n‐octane , 240min =1.3 %; CE n‐ octane, 60min =7.1 %, CE n‐ octane, 240min =0.5 %). At the same time, electrolyte recirculation significantly reduces wastes and limits the use of electrolyte components.