Kinetic Study of Complex Formation of by 2‐Nitroso‐1‐naphthol with Cobalt (II) Ion in Presence of Cetyltrimethylammonium Bromide Surfactant

Abstract

The kinetic complex formation of 0.001 M 2‐nitroso‐1‐naphthol (NAPH)with 0.01 M cobalt (II) ion (Co2+) in aqueous in presence of 0.02 M NaOH at 30°C in aqueous and/or in and 0.002 M cetyltrimethylammonium bromide (CTAB) have been studied using spectrophotometer at 430 nm. The present data showed that the reaction is first‐order with respect to [Co2+]T and NAPH. Also, k obs have constant values within concentration 0.015–0.05 M of NaOH and decreases with increase of concentration of CTAB to 0.002 M, then, k obs have constant values up to 0.005 M. The rate of the reaction in the presence of micelles has been explained with the pseudo‐phase model of the kinetics. Association constants of Co2+ and NAPH to CTAB micelle have been calculated. The activation parameters ΔH* and ΔS* have been obtained. The increase of reaction rate with sodium benzoate (C7H5O2Na) also has been discussed.