Investigation of electrochemical behavior of secondary products of capture of OH radicals by dimethyl sulfoxide molecules using laser photoemission

Abstract

Electrode reactions of intermediates formed during capture of OH radicals by dimethyl sulfoxide (DMSO) molecules were studied using laser photoemission in aqueous buffer solutions in the pH range from acidic to basic. The results were compared with characteristics of one-electron reduction of methyl radicals generated via photoemission from methyl halides CH3X (X = Cl, I). From these experiments, it was concluded that intermediates in these systems were identical since the primary product of capture of OH radicals by DMSO molecules, i.e., adduct (CH3)2SO. (OH), was spontaneously decomposed to form .CH3 with a time as low as <2 × 10−5 s. Some anomalies were found on time-resolved voltammograms of intermediates in the pH range from weakly basic to weakly acidic and at illumination times of an electrode with UV light Tm ≤ 90–300 ms. These features were presumably caused by rather slow formation of organomercury intermediates as interaction products of the components of the system DMSO—OH radical—mercury electrode.