596-49-6Relevant academic research and scientific papers
Quantitative analysis of dye decolourization reactions in mixed micellar systems of sodium dodecyl sulfate with tween-20, tween-80, and triton X-100
Lunkim, Kimkholhing,Luwang, M. Niraj,Srivastava, Sri K.
, p. 153 - 159 (2012)
The reaction of triphenylmethane dye (ethyl violet) with hydroxyl ion has been investigated in absence and presence of micelles. In micellar solutions, the solubilization of dye carbocation is observed. The reaction rate constant follows pseudo-first order kinetics with respect to the nucleophile. In presence of sodium dodecyl sulfate (SDS) micelles, an inhibitory effect is observed due to repulsion of the nucleophile to the strongly bound dye carbocation in the negatively charged SDS aggregate. The presence of nonionic surfactant reduces the inhibitory effect of the anionic SDS micelles. Quantitative analysis of the micellar data obtained has been done by applying a positive cooperativity model of enzyme catalysis. The value of n (index of cooperativity) has been found to be greater than 1 for all systems under study. The presence of solvents such as ethanol, n-propanol, and n-butanol reduces the inhibitory effect of the micelles.
Colorant compounds
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Page/Page column 32; 33, (2008/12/07)
A composition comprising a basic dye component and a counter ion comprising a waxy moiety.
A study on equilibrium and kinetics of carbocation-to-carbinol conversion for di- and tri- arylmethane dye cations in aqueous solutions: Relative stabilities of dye carbocations and mechanism of dye carbinol formation
Sen Gupta,Mishra,Radha Rani
, p. 703 - 708 (2007/10/03)
Arylmethane dye cations form a structurally interesting set of stable carbocations. A detailed study on rate-equilibria of carbinol formation from two diarylmethane and nine triarylmethane dye carbocations in aqueous solutions has been carried out using spectrophotometric measurements. The conclusions reached are : (i) The stability order found (auramine O>crystal violet = methyl violet > victoria blue R > victoria pure blue BO = ethyl violet > pararosaniline > brilliant green > malachite green > carbocation form of Michler's hydrol > methyl green), seems to be determined by an interplay of dye carbocation / carbinol conformation and stereoelectronic effects of substituents; and (ii) carbinol formation is general base catalysed and occurs by the rate determining attack of a H2O molecule on the dye carbocation centre via two kinetic pathways one mediated by another H2O molecule and the other by a OH ion.
Carbenium ion-carbinol equilibration for basic triarylmethane dyes: Relative reactivities of dyes in aq. solutions
Gupta, Susanta K. Sen,Arvind, Udai
, p. 998 - 1000 (2007/10/02)
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
The effects of cyclic terminal groups on the electronic absorption spectra of di- and tri-phenylmethane dyes
Beach, Steven F.,Hepworth, John D.,Jones, Peter,Mason, Donald,Sawyer, John,et al.
, p. 1087 - 1090 (2007/10/02)
The spectral shifts of the first absorption bands brought about by cyclic terminal groups in analogues of Michler's Hydrol Blue, Malachite Green, and Crystal Violet are determined mainly by inductive effects.Dye cations containing terminal pyrrolidino substituents are significantly more stable than those possessing piperidino groups as a result of differences in basicity brought about by a change in size of the saturated heterocyclic ring.
Effect of Pressure on the Rate of Alkaline Fading of Triphenylmethane Dyes in Cationic Micelles
Taniguchi, Yoshihiro,Iguchi, Akira
, p. 6782 - 6786 (2007/10/02)
The rates of alkaline fading of triphenylmethane dyes in cationic micelles have been measured at pressures up to about 2 kbar and at 25 deg C in 0.1 M Tris buffer solution.These rates follow the kinetics of the Michaelis-Menten type.The volume changes for the incorporation of dyes in the micellar phase are 14-15 cm3/mol for ethyl violet and brilliant green and 3-4 cm3/mol for crystal violet and malachite green.It was confirmed that these differences are due to the hydrophobicity of dyes.The activation volumes for the fading reaction in micellar phases are positive except in the case of the crystal violet-cetyltrimethylammonium bromide micellar system.However, the activation volumes in nonmicellar aqueous solutions are negative.The differences of the activation volumes between micellar and nonmicellar systems are discussed from the point of view of the general base catalysis, which contains both the water and hydroxide ion pathways.It was clear that micelles change the water control into hydroxide ion control.
