Date

Friday 23 Oct 2026

Time

15:15 - 15:45

Location

BW020

Supervisor

Dennis Hetterscheid

Jury

Jaco Geuchies

Medium-chain carboxylic acids (MCCAs, C5–C8) derived from biomass are promising feedstocks for the sustainable production of chemicals using renewable electricity. The Kolbe electrolysis converts carboxylic acids into alkyl radicals through anodic decarboxylation, which can dimerise to Kolbe products or follow non-Kolbe and Hofer–Moest pathways towards alkenes, alcohols and esters. This review examines how the selectivity of the Kolbe electrolysis of MCCAs can be steered by carboxylic acid chain length, electrode material, pH, electrolyte and carboxylic acid concentration. Most mechanistic insight stems from acetic acid on oxidised Pt anodes and may not apply to carboxylic acids with longer chains. Higher acid concentrations consistently favour Kolbe dimerization and suppress the oxygen evolution reaction (OER), and n-hexanoic acid shows the highest Kolbe efficiency among the compared MCCAs. However, the role of chain length, the hydrophobic interfacial layer, the mode of radical reaction (adsorbed or in solution), the existence of an inflection zone, and effects of interfacial pH remain unresolved, and interfacial pH is rarely considered. Studies systematically comparing electrodes and solvents for individual MCCAs are scarce. We therefore propose systematic comparisons of chain lengths and electrodes, interfacial studies including time-resolved pH at the electrode surface, solvent and electrolyte screening, and the comparison of one reaction across cell set-ups.