Oraganic sonoelectrochemistry. Reduction of fluorescein in the presence of 20 kHz power ultrasound: an EC′ reaction

Abstract

The electro-reduction of the dye fluorescein at mercury electrodes in basis aqueous solution is known to produce the stable semi-fluorescein radical. When the electrolysis is exposed to power ultrasound of intensity up to ca. 65 W cm^–2 the radicals are shown to be re-oxidised by means of hydroxyl radicals formed through the sonochemical decomposition of the aqueous solvent. The electrode process adopts the mechanistic characteristics of a ‘sono-EC′’ or ‘sono-catalytic’ reaction and this constitutes, to the author's knowledge, the first ever mechanistic asignment of this type.