- Equilibrium and Kinetic Studies on the Formation of Triphenylmethanols from Triphenylmethane Dyes
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For five kinds of triphenylmethane dyes, the rate constants of hydration and dehydration reactions, and equilibrium constants in an aqueous solution were measured by a stopped-flow method.An increase in the number of dialkylamino groups caused a decrease in the rates and the equilibrium constants of the hydration, and the more the electron-donating effect of the dialkylamino groups, the slower the hydration rate became.The more protonated quinonoids were easily converted to the corresponding alcohols.On the basis of the equilibrium constants, Malachite Green was ascertained to be the best reagent of the five dyes for ion association with heteropolyacids in an aqueous medium.
- Hagiwara, Takuyuki,Motomizu, Shoji
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p. 390 - 397
(2007/10/02)
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- Carbenium ion-carbinol equilibration for basic triarylmethane dyes: Relative reactivities of dyes in aq. solutions
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Equilibria and kinetics of carbenium ion-to-carbinol base reactions for a set of selected basic triarylmethane dyes in aq. buffer solutions of low ionic strength have been measured spectrophotometrically.Relative reactivities of the dyes towards nucleophilic attack by hydroxide ion, on the basis of both equilibrium constant and forward rate constant of the reaction, have been found to follow the same order: malachite green (MG)> brillant green (BG)>> Victoria pure blue BO(VB)> methyl violet (MV) = crystal violet (CV)> ethyl vioet (EV).A fairly good correlation between elec trophilicities of the dyes and ?R+ parameters of their 4-alkylamino substituents has been obtained
- Gupta, Susanta K. Sen,Arvind, Udai
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p. 998 - 1000
(2007/10/02)
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