Kinetics of oxidation of five vicinal diols, four non-vicinal diols, and two of their monoethers by bromine in strong acid solutions have been studied. The vicinal diols yielded the products arising out of glycol bond fission while the other diols yielded the hydroxycarbonyl compounds. The reaction is first order with respect to both bromine and the diol. The rate decreases with an increase in the acidity. The oxidation of [1,1,2,2-2H4] ethanediol showed the absence of a primary kinetic isotope effect. The value of solvent isotope effect, k(H2O)/k(D2O), at 303 K for the oxidation of ethanediol, propane-1,3-diol and 3-methoxybutane-1-ol are 4.71, 1.04 and 1.07 respectively. A mechanism involving a glycol bond fission has been proposed for the oxidation of the vicinal diols. The other diols are oxidised by a hydride-transfer mechanism as are monohydric alcohols.
Volume 134, 2022
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