Rhodium-catalysed decomposition of hydroxymercurated ethylene to ethanol and acetate

Abstract

2-Hydroxyethylmercury complexes dissolved in aqueous sodium hydroxide are catalytically decomposed by [{Rh(C₅Me₅)}₂(OH)₃]CI and related complexes to ethanol (14–18%), acetate (82–86%), and metallic mercury. Some hydrogen is also formed showing that water acts as an oxidiser in this reaction sequence. It is proposed that two decomposition paths co-exist one (ca. 30%) giving acetaldehyde, which then disproportionates into equal amounts of ethanol and acetate by a known process, and the other (ca. 70%) leading directly to acetate and hydrogen. Mechanisms are suggested. Propylene gives acetone (82%) and propan-2.01 (2%) by a similar route via 2-hydroxypropylmercury complexes, but 2-ethoxy-ethyl or – propyl complexes do not react.