ULTRASONIC EFFECTS ON ELECTROORGANIC PROCESSES - PART 10 - PRODUCT-SELECTIVITY IN MIXED KOLBE ELECTROLYSIS OF CARBOXYLIC-ACIDS

Product-selectivity was examined in mixed Kolbe electrolysis of carbox ylic acids on a platinum anode in aqueous methanolic solutions under u ltrasonic irradiation. It was found that an ultrasonic effect on the s electivity is caused not only by promotion of mass transport across th e electrode interface but also by adsorption control of intermediated radical species by ultrasonic acoustic and cavitation effects. Namely, formation of the one-electron oxidation products is favourable at low current densities compared with two-electron oxidation products under irradiation, while the two-electron oxidation is promoted at high cur rent density. This is the ultrasonic effect characteristic of the Kolb e electrolysis. The mechanism of the ultrasonic effect is discussed wi th a hypothesis.