Kolbe's Reaction of Higher Fatty Acids. III. Anode Potential in the Electrolysis of Laurio Acid with Platinum Anode

An aqueous solution of lauric acid, containing potassium hydroxide and potassium carbonate, was electrolysed at 40±0.5°C with smooth platinum electrodes. Not only were two constant anodic potential stages, 1.5∼1.6 and 2.4∼2.6V. vs. S.C.E., clearly found, but also an abrupt shift from the lower stage to the higher one was distinctly observed. The main reaction at the lower stage is the evolution of oxygen. In addition, at the higher stage the discharge of laurate ions is accompanied by an oxygen evolution that is markedly retarded compared with that at the lower stage. It may therefore, be inferred that the transition of potential from the lower stage to the higher is caused by the formation of a film of adsorbed laurate ions.