Oxidation of Crotonaldehyde by Quinolinium Chlorochromate (QCC). A kinetic study

摘要

The kinetics of oxidation of crotonaldehyde by quinolinium chlorochromate (QCC) in acetic acid-water mixture (50% v/v) was investiated spectrophotometrically at 293 K. The oxidation is first order each in [oxidant] and [substrate]. The reaction follows an acid catalysed path and the medium of low dielectric constant favours the reaction. Ionic strength has negligible effect. The reaction rates have been determined at different temperatures and the activation parameterrs have been computed. Determination of QCC-crotonaldehyde stoichiometry indicates that one mole of crotonaldehyde reacts with one mole of QCC. The mechanism proposed involves a slow attack of QCC on crotonaldehyde forming a four-centre intermediate state which which ultimately decomposes to give an epoxide.