• Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      https://www.ias.ac.in/article/fulltext/jcsc/104/01/0067-0076

    • Keywords

       

      Chromium(VI); N-acetylphenothiazine; N-methylphenothiazine; oxidation; kinetics and mechanism

    • Abstract

       

      The kinetics of oxidation of N-acetylphenothiazine (NAPT) by Cr(VI) in 80% acetic acid-20% water (v/v) mixture is first-order each in [NAPT] and [Cr(VI)]. The reaction is catalysed by added acid with a third-order dependence in [HCIO4], Increase in polarity of the solvent medium decreases the rate. The oxidation is insensitive to variations in ionic strength as well as added acrylamide. Oxidations of phenothiazine (PT) and N-methylphenothiazine (NMPT) under similar conditions are found to be very fast. However kinetic investigations with NMPT in an acetic acid-sodium acetate buffer show first-order dependence each in [NMPT] and [Cr(VI)] and a fractional-order dependence in [H+] in the pH range 1.80-3.09. Increase in polarity of the medium increases the rate. In both the cases, the corresponding sulphoxides are identified as oxidation products. Based on the kinetic results, mechanisms for oxidations are proposed.

    • Author Affiliations

       

      K Pitchumani1 V Subramanian1 P P Jegatheesan1 C Srinivasan2

      1. School of Chemistry, Madurai Kamaraj University, Madurai - 625021, India
      2. Department of Materials Science, Madurai Kamaraj University, Madurai - 625021, India
    • Dates

       
  • Journal of Chemical Sciences | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2017-2019 Indian Academy of Sciences, Bengaluru.