Articles written in Proceedings – Section A
Volume 59 Issue 1 January 1964 pp 68-76
The rates of oxidation of several aromatic aldehydes with chromic acid have been measured using several mixtures of acetic acid and water as solvents. This study points to the fact that the oxidation proceeds by an iondipole mechanism. Evidence has also been obtained from these studies that the active oxidant is a cationic species, such as HCrO3/+ or H3CrO4/+. Amis’ equation for an ion-dipole reaction gives remarkably good values of ‘
Volume 59 Issue 2 February 1964 pp 93-101
Both structural and solvent influences on the rate of oxidation of a series of aromatic aldehydes by chromic acid show the following features: the formation of a chromate ester is not a prerequisite to oxidation; in the rate-determining step of the reaction the C-H hydrogen is removed as a hydride anion. That the rate-dermining step involves a two-electron transfer has been proved by a study of the Induction Factor method. A tentative mechanism, based on an analogy to the well-known ‘SN2’ process, has been proposed.
Volume 60 Issue 6 December 1964 pp 416-421
The effect of added salts and oxidizable cations on the chromic acid oxidation of aromatic aldehydes in acetic acid-water mixtures is discussed and a tentative scheme for the intermediate stages of reduction of the chromium species is presented.