The oxidation of six aliphatic aldehydes by quinolinium chlorochromate (QCC) in dimethyl sulfoxide (DMSO) leads to the formation of
corresponding carboxylic acids. The reaction is first order in QCC. A Michaelis-Menten type of kinetics is observed with respect to the
aldehydes. The reaction is catalysed by hydrogen ions, the hydrogen-ion dependence has the form: kobs=a + b[H+
]. The oxidation of
deuteriated acetaldehyde, MeCDO, exhibited a substantial primary kinetic isotope effect (kH/kD=5.78 at 298 K). The oxidation of
acetaldehyde has been studied in nineteen different organic solvents. The solvent effect has been analysed using Taft's and Swain's
multiparametric equations. The rate constants correlate well with Taft’s
* values; reaction constants being negative. A mechanism
involving transfer of hydride ion has been suggested.
Key words: aliphatic aldehydes, correlation analysis, quinolinium chlorochromate, kinetics, mechanism, oxidation
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