Influence of cetyltrimethylammonium bromide/ sodium dodecyl sulfate micelles on the oxidation of L-arginine by N- bromophthalimide in presence of HClO4

摘要

The kinetics of oxidation of L-arginine by N-bromophthahmide in the presence of HClO4 has been investigated in different media, viz., aqueous and micellar media of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS). The reaction is found to be dependent on substrate, [H~+], CH3COOH and surfactant. The order of oxidation is found to be positive fractional order with respect to L-arginine and negative fractional order with respect to [H~+]. Polarity of the medium also has an effect on the rate of reaction. Based on experimental findings, a mechanism has been proposed and discussed for the oxidation reaction. The micelles influence the rate of reaction significantly. Rate enhancement is observed in the presence of CTAB while an inhibiting effect is observed in the presence of SDS. These effects have been further analysed by means of the pseudo-phase models based on which the rate constant and binding constants have been evaluated.