Kinetics of oxidation of organic compounds by silver(II) in aqueous perchloric acid solution. Part 3. Aliphatic aldehydes

Abstract

The stoicheiometries and kinetics of the silver(II) oxidation of formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, and pivaldehyde have been investigated at 8.0, 14.0, and 22.0 °C in aqueous perchloric acid media (1.00 ⩽[HClO₄]⩽ 4.00M; µ 4.0M). The kinetics were monitored by a stopped flow technique. The reactions occur with the stoicheiometry H₂O + 2Ag^II+ RCHO → 2Ag^I+ 2H⁺+ RCOOH. The rate-determining step is first order in each reactant, and involves both Ag²⁺ and AgOH⁺ species. No direct evidence for complex formation between the reactants was obtained. The results are discussed with reference to enolization and hydration equilibria of the substrates. gem-Diol forms of the aldehydes are suggested as the active species.