Reduction electrochimique a l'electrode de mercure de composes α-hydroxycarbonyles en solution aqueuse α — I. Glyoxals RCOCH(OH) 2

Abstract

Reduction at the mercury electrode in aqueous solution of the unhydrated form of glyoxals exhibits evidence of a reversible system: RCOCHO + 2 e + 2H + ⌉har2; RC(OH)CHOH with RCH 3 or C 6H 5. For the hydrated form C 6H 5COCH(OH) 2, investigation indicated occurrence of two types of irreversible processes. In neutral media transfer of two electrons involve either the hydrogenolysis of the COH bond, yielding hydroxyacétophenone: C 6H 5COCH 2OH, or alternatively the reduction of the keto grouping yielding mandelaldehyde: C 6H 5CHOHCHO. The COH cleavage is exclusive in acidic media and for aliphatic glyoxals RCOCH(OH) 2.