Catalytic action of CTAB/KBr/C sub(9)OH micellar media on the basic hydrolysis of crystal violet

• Published in: Journal of dispersion science and technology Vol. 38; no. 6; pp. 845 - 851
• Main Authors: Karayil, Jasila, Sreejith, Lisa
• Format: Journal Article
• Language: English
• Published: 03.06.2017
• Subjects: Crystals; Fluorescence; Hydrolysis; Hydroxides; Media; Morphology; Rate constants; Surfactants
• ISSN: 0193-2691; 1532-2351
• DOI: 10.1080/01932691.2016.1207187

The kinetics of basic hydrolysis of crystal violet (CV) in CTAB/KBr/C sub(9)OH 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 C sub(0). The enhancement of reaction rate with C sub(0) 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 C sub(0) suggests an increase in dye-micelles interaction with C sub(0.) 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 super(-) and Br super(-) ions for the reaction center. The influence of [OH super(-)] 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 super(-)].