• Kinetics and mechanism of oxidation of dimethyl sulphoxide by sodium bromate-sodium bisulphite reagent in aqueous medium

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      https://www.ias.ac.in/article/fulltext/jcsc/114/02/0149-0154

    • Keywords

       

      Oxidation of DMSO; sodium bromate-sodium bisulphite reagent

    • Abstract

       

      Rates of oxidation of dimethyl sulphoxide (DMSO) by HOBr producedin situ from sodium bromate-sodium bisulphite reagent have been studied iodometrically in aqueous medium. The order in [DMSO] is one when [DMSO] < 001 mol dm-3, fractional when [DMSO] is between 0.01 and 0.5mol dm-3 and zero when (DMSO) > 0.5 mol dm-3. Different rate laws are operative under these three conditions though HOBr is the effective oxidizing species in all the cases. A mechanism involving an intermediate four-membered cyclic transition state between DMSO and HOBr (formation constantK), which decomposes in a slow step with a rate constant(k) has been proposed. Thermodynamic parameters for the adduct formation step and activation parameters for the first-order decomposition of the adduct step have been evaluated in the temperature range 308–323 K. Activation parameters have also been determined while the orders in [DMSO] are unity and zero. The reaction product has been identified as dimethyl sulphone (DMSO2).

    • Author Affiliations

       

      J Viroopakshappa1 V Jagannadham1

      1. Department of Chemistry, Osmania University, Hyderabad - 500 007, India
    • Dates

       
  • Journal of Chemical Sciences | News

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