NISCAIR Online Periodicals Repository

Research Journals >
Indian Journal of Chemistry -Section A (IJC-A) >
IJC-A Vol.46A [2007] >
IJC-A Vol.46A(11) [November 2007] >

Title: Chromium(VI) catalyzed oxidation of indole in aqueous acetic acid
Authors: Meenakshisundaram, Subbiah
Sarathi, N
Issue Date: Nov-2007
Publisher: CSIR
IPC CodeInt. Cl. ⁸ CO7B33/00
Abstract: The catalytic activity of picolinic acid, 1,10-phenanthroline, oxalic acid, 2,2'-bipyridyl and ethylenediamine tetracetic acid have been investigated in the chromium(VI) oxidation of indole in aqueous acetic acid medium. The catalysts increase the electrophilic activity of the oxidant and the Cr(VI)-Cat complex is believed to be the reactive electrophile. The proposed reaction pathway involves the electrophilic attack of the Cr(VI)-Cat complex at the ethylenic bond of the indole ring to give an indoleninic intermediate. The reaction is routed through via a termolecular complex, Cr(VI)-Cat-IND, the decomposition of which in slow rate determining step is envisaged to explain the reactivity. In presence of the catalyst, indole is oxidized by chromium(VI) to give oxindole as the major product, under most conditions. The conversion is favoured in a medium of low dielectric constant. The failure to observe inhibition in the presence of acrylonitrile suggests the non-radical mechanistic pathway. The ratio, k(D2O)/k(H2O) ≈ 1, does not seem to indicate any significant solvent isotope effect. Cobalt(III) enhances the reactivity while pyridine and chromium(III) depress the reactivity. The relative catalytic activity for indole oxidation in the presence of different catalysts reveals that picolinic acid is the best catalyst under the experimental conditions while activity of EDTA is minimum. A detailed interpretation of the redox mechanism based on the available kinetic data has been proposed.
Page(s): 1778-1781
ISSN: 0376-4710
Source:IJC-A Vol.46A(11) [November 2007]

Files in This Item:

File Description SizeFormat
IJCA 46A(11) 1778-1781.pdf75.46 kBAdobe PDFView/Open
 Current Page Visits: 1108 
Recommend this item


Online Submission of Articles |  NISCAIR Website |  National Knowledge Resources Consortium |  Contact us |  Feedback

Disclaimer: NISCAIR assumes no responsibility for the statements and opinions advanced by contributors. The editorial staff in its work of examining papers received for publication is helped, in an honorary capacity, by many distinguished engineers and scientists.

CC License Except where otherwise noted, the Articles on this site are licensed under Creative Commons License: CC Attribution-Noncommercial-No Derivative Works 2.5 India

Copyright © 2015 The Council of Scientific and Industrial Research, New Delhi. All rights reserved.

Powered by DSpace Copyright © 2002-2007 MIT and Hewlett-Packard | Compliant to OAI-PMH V 2.0

Home Page Total Visits: 164308 since 01-Sep-2015  Last updated on 21-Jun-2016Webmaster: