SPECTROELECTROCHEMICAL STUDIES OF P-BENZOQUINONE REDUCTION IN AQUEOUS-MEDIA

p-Benzoquinone reduction has been studied in aqueous solutions employi ng spectroelectrochemical techniques, and an intermediate species thus far believed to be unstable in aqueous media has been shown to be rea sonably stable in unbuffered solutions. The detection of this intermed iate species, which is produced as a one-electron transfer product, i. e. anion radical, suggests that the e(-)H(+)e(-)H(+) mechanism, in whi ch e(-) and H+ represent electron transfer and protonation steps respe ctively, is a major reaction pathway during the electrochemical reduct ion of benzoquinone to the final product, hydroquinone, in unbuffered solutions. In buffered solutions, however, p-benzoquinone reduction is a two-electron process, as has been well known. A few anomalies disco vered during the reduction of p-benzoquinone in aqueous media are disc ussed.