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Department of Chemistry, J. N. V. University, Jodhpur-342 011, Rajasthan, India E-mail : drpkvs27@yahoo.com Department of Chemistry, RGP Mahavidyalaya, Kolar Road, Bhopal-462 042, Madhya Pradesh, India chemical Research Center, Hungarian Academy of Sciences, H-1025, Pusztaszeri u. 59-67, Budapest, Hungary Faculty of Science, National Law University, Mandore, Jodhpur-342 304, Rajasthan, India Manuscript received 17 April 2012, accepted 20 April 2012 The oxidation of thirty-six ortho-, meta- and para-substituted benzaldehydes by bis(pyridine)silver permanganate (BPSP) resulted in the formation of the corresponding benzoic acids. The reaction is first order with respect to both BPSP and aldehydes. The reaction is catalyzed by hydrogen ions. The rate of reaction increases with an increase in the amount of acetic acid in the solvent. The correlation analyses of the rate of oxidation of thirty-six aldehydes were performed in terms of Charton's LDR and LDRS equations. The rate of oxidation of meta- and para-substituted benzaldehydes showed excellent correlation with Charton's LDR equation. The rates of ortho-compounds showed excellent correlation with LDRS equation. The oxidation para-compounds is more susceptible to the delocalization effect. The oxidation of ortho- and meta-compounds exhibited a greater dependence on the field effect. The polar reaction constants are negative indicating an electron-deficient centre in the rate-determining step. A mechanism involving a nucleophilic attack on the carbonyl group by a permanganate-oxygen and a subsequent hydride transfer has been proposed. |
