Kinetics and Mechanism of Oxidation of Acetophenone Semicarbazone and p-Methoxyacetophenone Semicarbazone by Peroxodisulphate

Department of Chemistry, Seethalakshmt Ramaswamt College (Autonomous), Trichy-620 002 Manuscript received 2 February 1993, revised 13 April 1993, accepted 28 May 1993 Kinetics of oxidation of acetophenone semicarbazone and p-methoxyacetophenone semicarbazone by peroxodisulphate have been studied in aqueous acetic acid medium. The reaction exhibits a first order dependence with respect to [PDS]. A plot of k-1 vs [substrate] is linear. Effects of added H+ and salt have also been investigated. The stoichiometry is 1 : 1. A suitable mechanism has been proposed to account for these observations. The large negative ΔS\(\pm\) values indicate that the activated complexes are addition complexes of the substrate and PDS. The substituent effect on the reaction rate has been studied. A sharp comparison is made with the corresponding reactions of the similar peroxide \(SO_5^-\)