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8349213 
Journal Article 
Free energy relationships for the reaction series-MnII catalyzed periodate oxidation of aromatic amines 
Kaushik, RD; Singh, O; Tyagi, P; Yadav, R; Singh, J 
2014 
Yes 
Journal of the Indian Chemical Society
ISSN: 0019-4522 
91 
10 
1959-1966 
English 
The studies are aimed at testing the validity of various free energy relationships for the reaction series, MnII catalysed periodate oxidation of substituted anilines in acetone-water medium. The progress of catalysed oxidation of twenty anilines was followed spectrophotometrically by recording the absorbance of the reaction mixture at pre-determined absorption maxima of the reaction intermediate at different time. Arrhenius equation is followed by all reactions of the series. Hammett,Exner, Taft, Van Bekkum and Sekigawa plots were found to be concave-upward while Brown and Okamoto plot is linear with good correlation. The value of reaction constant, p, from Brown and Okamoto plot, is-1.46 which is suggestive of retardation of reaction by the electron withdrawing groups and acceleration by the electron donating groups as well as an electrophilic attack on the anilino nitrogen by the periodate ion during oxidation process. The negative value of p also indicates that the electron donating substituents stabilize by resonance, a transition state having a high positive charge on the reaction center, i.e. N of the anilino group and this facilitates the bond breaking process in the transition state. Further, the ionization of anilines is not a deciding step in the reaction mechanism. The observed free energy relationships are also suggestive of same interaction mechanism being followed in the reactions belonging to this reaction series. © 2014 Scientific Publishers. All Rights Reserved. 
Aromatic amines; Free energy relationships; MnII catalysed; Periodate oxidation