Kinetic cosolvent effects on the alkaline fading of crystal violet in the presence of sodium dodecyl sulfate micelles

Abstract

The alkaline fading reaction of crystal violet (CV) in anionic micelles of sodium dodecyl sulfate (SDS) in the presence of various amounts of cosolvents, ethanol, propanol, ethylene glycol and propylene glycol, was studied under pseudo-first-order conditions. The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of CV at 590 nm. The results indicated that SDS micelles exhibited an inhibiting effect on this reaction and this can be reasonably accounted for in terms of electrostatic interactions. Presence of cosolvents reduced the inhibitory effect of SDS micelles, i.e. increased the reaction rate. Effectiveness of cosolvent as accelerators of SDS inhibited reaction is in the following order: propanol > ethanol > propylene glycol > ethylene glycol. (c) 2005 Elsevier B.V All rights reserved.