Electrocatalytic reductive splitting of CO and COH bonds at platinum electrodes

Abstract

A survey is given of those reductive electrocatalytic transformations of carbonyl compounds and molecules containing COH bonds in special positions (allyl position, α position with respect to a carbonyl group) where the splitting of the carbon-oxygen bond occurs. These reactions take place in acid medium at noble metal (mostly platinized platinum) electrodes. In the case of simple mono- and di-carbonyl compounds (acetone, butanone, acetaldehyde, bi-acetyl, glyoxal, etc.) the formation of the corresponding hydrocarbons may be observed, but these reactions are accompanied by the formation of alcohols or diols, respectively. In the case of allyl alcohol, crotyl alcohol, butenediol, glykolaldehyde, acetoine, etc. the splitting of the COH bond precedes the reductive transformation of ▪ groups and double bonds. As a consequence of this step, hydrocarbons are formed in the overall process. The possible reaction path are considered and some problems connected with the mechanism and selectivity of these processes are discussed.