Ultrasonic effects on electroorganic processes: Part 14. Indirect electroreduction of benzyl chlorides with anthracene redox-mediatory system

Ultrasonic effects were observed in the indirect electroreduction of benzyl chlorides with a radical anion mediator electrogenerated from anthracene. Both the current efficiency for the toluenes formed and the current density (reaction rate) at a working electrode were significantly increased in potential-controlled electrolysis under ultrasonic irradiation (20 kHz). These effects are important from a practical aspect and are rationalized as being due to mass transport promotion caused by ultrasonic cavitation. Although the efficiency could be also increased in the direct electroreduction in the absence of the mediator under irradiation, the current density was only slightly increased.