Crystal violet alkaline fading

The alkaline fading of crystal violet (4-Me2NC6H4)3C, in micelles of CTABr modified by 1-hexanol or by 1-octanol has been treated quantitatively by estimating the local concentration of OH in the interfacial region by solving the Poisson-Boltzmann equation. The local second-order rate constants calculated by this method are very similar to those calculated for normal aqueous micelles of CTABr [107], but these rate constants are uncertain because the authors did not correct for the competing reaction with alkoxide ion formed by deprotonation of the alcohol by OH (cf Refs. 79 and 80). 

The alkaline fading of crystal violet (4-Me2NC6H4)3C+ in cationic W/O microemulsions of CTABr-alcohol-cyclohexane occurs in the water pools [113]. The corresponding reactions of crystal violet and malachite green, (4-Me2NC6H4)2C Ph, in anionic W/O AOT-isooctane microemulsions also occur in the water pools, and rate data were analyzed in terms of their size and the competing base-promoted hydrolysis of AOT [114]. This reaction with crystal violet is strongly inhibited by ClOj, which pairs with the carbocation and blocks nucleophilic attack,... 

The alkaline fading of crystal violet in AOT micelles formed in supercritical ethane as a continuous phase has been studied by Ikushima et al. [20,70,71] (Scheme 12.5). The reaction rate of fading in this system was reported to increase compared with that in H20/AOT/heptane at high pressures under similar conditions. 

SCHEME 12.5 The alkaline fading of crystal violet (CV) by using AOT micelles formed in supercritical ethane. (Adapted from Ref. [71 ] with permission of Elsevier.)... 

Ikushima Y, Shervani Z, Saito N, Arai M. The promotion of alkaline fading of crystal violet by AOT micelles dispersed in supercritical ethane medium. J Colloid Interf. Sci 1997 191 177-83. 

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