Ultrasonic Effects in Electrochemical Processes

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Reaction control of electrode processes is important in synthetic electrochemistry. Therefore, functionality-modification of the electrode interface has received much attention so far. In this work, a new concept for the electrode interface modification is established by means of ultrasonic effects.This approach governs the structure of the work.At first, a mechanistic study on ultrasonic effects in organic electrode processes was carried out. From experimental and theoretical considerations, it was varified that the effects are caused by promotion of mass transport in the electrode interface by ultrasonic irradiation at a power higher than the cavitation threshold value.Hence, influences of placement of electrolytic cell, electrode and ultrasonic oscillator on electrode reactions were also examined in order to establish a guideline for electrochemical application of ultrasounds. As a result, it was found that the electrode reactions were greatly affected by placement of the constituen … More ts since longitudinal ultrasonic waves traveling in liquid would cause reflection, interference and attenuation. Therefore, it is necessary to take account for the placement of constituents.Moreover, effects of ultrasounds on electroorganic processes have been extensively examined in a series of investigations. The current efficiency and / or product selectivity in electroorganic reactions were found to be greatly affected by ultrasonic waves. In addition, the two- and three-dimentionally dense and uniform polymer films could be prepared by electrooxidative polymerization under ultrasonic irradiation.It was also found that stereoselectivity in the reductive debromination of vic-dibromides remakably depends on the frequency of ultrasounds. In particular, the stereoselectivity was controlled by a novel effect of ultrasounds at MHz ranges, alternatively to the cavitation phenomenon at kHz ranges. From the mechanistic consideration, it was found that the effect of ultrasounds at MHz ranges is due to the ultrasonic reluxation of vic-dibromides. This fact would produce a new developments in sonochemistry.From this study, it was stated that ultrasounds offer a useful method for purposive reaction control in a variety of electroorganic processes. Less