Kinetic data on the rates of quinolinium dichromate oxidation of a series of aliphatic aldehydes have been determined and discussed with reference to aldehyde hydration equilibria. Kinetic results support a pathway proceeding via a rate-determining oxidative decomposition of a chromate ester of an aldehyde hydrate. A cyclic transition state is suggested; being a Hückel-type system (4n + 2), this would be an allowed process. The deuterium isotope effect for the oxidation of acetaldehyde (kH / kD = 6.4) indicated a carbon-hydrogen cleavage rather than a carbon-carbon cleavage
