• Mechanism of positive iodine reactions: Kinetics of oxidation of semicarbazide by iodamine-T, iodine monochloride and iodine

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      https://www.ias.ac.in/article/fulltext/jcsc/100/04/0275-0286

    • Keywords

       

      Kinetics of oxidation; semicarbazide; iodamine-T; iodine monochloride; positive iodine

    • Abstract

       

      Kinetics of oxidation of semicarbazide (SC) by iodamine-T (IAT), iodine monochloride and aqueous iodine has been studied in aqueous perchloric acid medium. The rate laws followed by the oxidation of SC were determined. The rates decreased slightly with increase in ionic strength of the medium in IAT and ICI oxidations, while the reverse trend was observed with I2. Decrease in dielectric constant of the medium increased the rates with IAT and ICI, while it decreased the rate in I2 oxidations. Addition of the reduced product,p-toluene-sulphonamide had no effect on the rate with IAT. Addition of I had slight negative and positive effects on the rates of oxidations with IAT and ICI, respectively, but the negative effect was considerable in I2 oxidations. Mechanisms consistent with the observed rate laws have been proposed and discussed. Rate determining steps have been identified and their coefficients calculated. These constants were used to predict the rate constants from the deduced rate laws as [SC], [H+] and [I] varied. Reasonable agreement between the calculated constants and experimental values provide support for the suggested mechanisms.

    • Author Affiliations

       

      B Thimme Gowda1 J Ishwara Bhat1 2

      1. Department of Post-Graduate studies and Research in Chemistry, Mangalore University, Mangalagangothri, Mangalore - 574 199, India
      2. Govinda Dasa College, Suratkal - 574 158, India
    • Dates

       
  • Journal of Chemical Sciences | News

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