Role of added chloride ions in alteration of reaction pathway in the oxidation of cyclic ketones by dichloroisocyanuric acid—A kinetic study

• Published in: Russian Journal of Physical Chemistry A Vol. 89; no. 3; pp. 376 - 383
• Main Authors: Lakshman Kumar, Y., Venkata Nadh, R., Radhakrishnamurti, P. S.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.03.2015
• Subjects: Chemical Kinetics and Catalysis; Chemistry; Chemistry and Materials Science; Physical Chemistry; cyclic ketones; enolisation; chloride ion; kinetics; reaction pathway; dichloroisocyanuric acid
• DOI: 10.1134/S0036024415030176
• ISSN: 0036-0244

Effect of added chloride ions on kinetics and pathway of reaction between cyclic ketones (five to eight membered rings) and dichloroisocyanuric acid (DCICA) was studied in aqueous acetic acid—perchloric acid medium. Formation of aliphatic dicarboxylic acids as the end products demonstrates the ring cleavage oxidation. Positive effect of acid and negative effect of dielectric constant on the reaction rate reveals a interaction between positive ion (oxidant in the form of H 2 OCl + ) and dipolar substrate molecule. Zero and first orders by oxidant in absence and presence of added chloride ions illustrates the participation of substrate as enolic form of ketone and protonated ketone, respectively, in the rate determining steps. The observed order of reactivity of cyclic ketones (cyclohexanone > cyclooctanone > cyclopentanone > cycloheptanone) was explained on the bases of ring strain, change of hybridization and conformational considerations. The envisaged plausible mechanism based on order of reactants in presence and absence of added chloride ions was substantiated by the order of Arrhenius parameters.