• P S Raghavan

      Articles written in Journal of Chemical Sciences

    • Micellar catalysed chlorination of acetophenone by chloramine-T

      V Raghunathan P S Raghavan K Vaidyanathan V S Srinivasan

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      The chlorination of acetophenone by chloramine-T cat has been catalysed by anionic micelle, sodium lauryl sulphate (NaLS). Though the order in cat is one, the order in acetophenone is fractional at lower concentration and becomes zero at higher concentration in the presence and absence of NaLS. This is probably due to the change in rate-determining step. At lower acetophenone concentration, the decomposition of enol-chlorinating species complex is rate-determining whereas at higher concentration, the formation of chlorinating species is rate determining. The graph ofk2 versus detergent concentration is sigmoidal and the positive co-operativityversus log[D] graph is 1.11, indicating possible interaction between micelle and substrate.

    • Micellar catalysed oxidative cyclisation of 1,3,5-triaryl formazan

      R Balakrishnan P S Raghavan Vangalur S Srinivasan

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      The kinetics of Tl(III) acetate oxidation of 1,3,5-triaryl formazan has been studied in 90% aqueous HOAc, in the presence of added anionic detergent, sodium-lauryl sulphate(NaLS) and cationic detergent, cetyltrimethylammonium bromide (ctab). Both surfactants enhance the reaction rate, indicating that the reactive species involved is possibly neutral. From the substituent influence observed in the micellar phase Hammett correlations have been attempted. Higher negative ϱ values obtained in the presence of ctab, indicate that the transition state is more electron-deficient. The positive co-operativity calculated for the micellar catalysed reactions (3.0) indicates possible hydrophobic interaction between micelle and formazan.

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