Kinetics and mechanism of the oxidation of diols by ethyl N-chlorocarbamate

Abstract

The kinetics of oxidation of five vicinal and four non-vicinal diols, and two of their monoethers by ethyl N-chlorocarbamate (ECC) have been studied. The vicinal diols yielded products arising out of the glycol bond fission while the other diols yielded hydroxycarbonyl compounds. The reaction is first order with respect to ECC, the diol, and hydrogen ions. Addition of ethyl carbamate and acrylonitrile has no effect on the reaction. The oxidation of [1,1,2,2-²H₄]ethanediol showed the absence of a primary kinetic isotope effect. The values of solvent isotope effect, k(H₂O)/k(D₂O), at 303 K for the oxidation of ethanediol, propane-1,3-diol and 3-methoxybutan-1-ol are 3.51, 2.21 and 1.98 respectively. An acyclic mechanism involving glycol bond fission has been proposed for the oxidation of the vicinal diols. The other diols are oxidized by a hydride-transfer mechanism as are monohydric alcohols.