Catalytic action of CTAB/KBr/C9OH micellar media on the basic hydrolysis of crystal violet

Abstract

ABSTRACTThe kinetics of basic hydrolysis of crystal violet (CV) in CTAB/KBr/C9OH micellar media was investigated under pseudo-first-order conditions. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of CV at 590 nm. It was observed that the pseudo-first-order rate constant increases with increase in C0. The enhancement of reaction rate with C0 is explained on the basis of dependence of reaction rate on micellar morphology. Further, the viscosity and DLS analysis supports nonanol-induced morphological transitions. Fluorescence spectroscopy has been used to understand dye–micelles interactions. The enhancement of fluorescence intensity of CV with C0 suggests an increase in dye–micelles interaction with C0. The concentration of surfactant and salt had a marked effect on reaction rate. The inhibition of reaction rate at high concentration of surfactant and salt is due to the ionic competition of OH− and Br− ions for the reaction center. The influence of [OH−] on CV hydrolysis was also investigated. The results show that the pseudo-first-order rate constant, k’, increases linearly with hydroxide ion concentration, indicating first-order dependence on [OH−].