Kinetics and mechanism of the oxidation of some aliphatic ketones by n-bromoacetamide in acidic media

Kinetics of the oxidation of methyl ethyl ketone (MEK) and diethyl ketone (DEK) by N-bromoacetamide (NBA) have been studied in perchloric acid media in the presence of mercuric acetate. A zero order dependence to NBA and a first-order dependence to both ketones and H⁺ have been observed. Acetamide, mercuric acetate and sodium perchlorate additions have negligible effect while addition of acetic acid has a positive effect on the reaction rate. A solvent isotope effect (K₀D₂O/k₀H₂O = 2.–.4 and 2.2-2.5 for MEK and DEK, respectively) has been observed at 40°. Kinetic investigations have revealed that the order of reactivity is MEK > DEK. The rates were determined at four different temperatures and the activation parameters were evaluated. The main product of the oxidation is the corresponding 1,2-diketone. A suitable mechanism consistent with the above observations has been proposed.