Influence of cetyltrimethylammonium bromide/1-hexanol and cetyltrimethylammonium bromide/1-octanol mixed micelles on the basic hydrolysis of crystal violet. Different theoretical approaches

Langmuir ◽  
1990 ◽  
Vol 6 (4) ◽  
pp. 775-782 ◽  
Author(s):  
Mercedes Valiente ◽  
Elvira Rodenas
1970 ◽  
Vol 24 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Ferdousi Begum ◽  
Md Yousuf A Molla ◽  
M Muhibur Rahman ◽  
Md Abu Bin Hasan Susan

Kinetics of the alkaline hydrolysis of crystal violet (CV) in micelles, reverse micelles and microemulsions of a cationic surfactant, cetyltrimethylammonium bromide (CTAB) was studied at 25 ± 0.1 oC using spectrophotometric method. The rate of alkaline hydrolysis of CV was catalyzed by micellar solutions of CTAB. The pseudo first order rate constant (k') has been found to decrease upon incorporation of 1-butanol to cationic CTAB micelles, which displaces the substrate from the micellar into the aqueous phase. In CTAB/cyclohexane/1-butanol/water system, as the content of 1-butanol increases, specific conductivity and density of the microemulsions and reverse micelles decrease. The change in physical properties also causes change in reaction environment. A change from a micelle-rich (o/w) to a reverse micelle-rich (w/o) condition is apparent for microemulsions and consequently the k' vs. % wt. of 1-butanol profiles show an initial decrease in the k' followed by a gradual increase and finally, to a sharp increase with increasing 1-butanol content. Microemulsions and reverse micelles thus offer the potential to control rate of a reaction by formation of micelles in water phase and reverse micelles in oil phase. DOI: http://dx.doi.org/10.3329/jbcs.v24i2.9706 Journal of Bangladesh Chemical Society, Vol. 24(2), 173-184, 2011


2019 ◽  
Vol 31 (3) ◽  
pp. 651-655
Author(s):  
Qidist Yilma ◽  
Dunkana Negussa ◽  
Y. Dominic Ravichandran

Kinetics of alkaline hydrolysis of crystal violet, a triphenylmethane dye in the micellar environment of cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfonate (SDS) and binary mixtures of these surfactants was studied. The regression parameters, together with rate constants and binding constants were obtained by analyzing the rate surfactant profiles using cooperativity model. It was observed that the reaction was catalyzed by both surfactants. The catalytic factor increased by 10 times in SDS and 38 times in CTAB indicating that binding of crystal violet to the micellar surface is stronger in pure CTAB than SDS but the strength drastically reduced in the mixtures of the surfactants. Reduction of binding constant became more important as the mole fraction of CTAB was improved in the mixture. The kinetic data were investigated using Piszkiewicz model and Raghavan-Srinivasan model. The data obtained from the models were in good agreement with the experimental values.


2017 ◽  
Vol 231 ◽  
pp. 655-662 ◽  
Author(s):  
Lvjie Yang ◽  
Yunhui Xiang ◽  
Lin Chen ◽  
Dan Zhang ◽  
Chenyi Wu ◽  
...  

1980 ◽  
Vol 33 (8) ◽  
pp. 1771 ◽  
Author(s):  
TJ Broxton ◽  
NW Duddy

The basic hydrolysis of a number of α-substituted N-methyl-N-p- nitrophenylacetamides has been studied both in the presence and absence of micelles of cetyltrimethylammonium bromide (ctab). Unlike the related p-nitrophenyl esters of a-substituted acetic acids, no evidence for the operation of the E1cb mechanism in the basic hydrolysis has been detected. Reasons for the differences between the amides and esters are discussed. Substituent effects on the hydrolysis of the amides have been studied both by single-parameter and dual-parameter analysis.


Langmuir ◽  
2004 ◽  
Vol 20 (3) ◽  
pp. 606-613 ◽  
Author(s):  
L. García-Río ◽  
J. R. Leis ◽  
J. C. Mejuto ◽  
A. Navarro-Vázquez ◽  
J. Pérez-Juste ◽  
...  

1981 ◽  
Vol 34 (8) ◽  
pp. 1615 ◽  
Author(s):  
TJ Broxton

The hydrolysis of N-methyl-N-(4'-nitrophenyl)-2-phenoxyacetamide has been studied in the presence and absence of micelles of cetyltrimethylammonium bromide. The micellar catalysis depends on the reaction system being used. Hydrolysis in the presence of sodium hydroxide, and in the presence of borate, carbonate/bicarbonate and triethylamine/triethylammonium chloride buffers has been examined. The magnitude of catalysis is shown to depend on the buffer system used, the concentration of detergent, the concentration of the buffer, the pH and the presence of any added salts. The results confirm that it is unrealistic to compare independent sets of results on different compounds unless the conditions for obtaining those results are identical. ��� Hydrolysis in the presence of carbonate/bicarbonate buffers is shown to be subject to buffer catalysis and, by analogy with results for p-nitrophenyl acetate, nucleophilic catalysis by carbonate ions is suggested.


1981 ◽  
Vol 34 (11) ◽  
pp. 2313 ◽  
Author(s):  
TJ Broxton

The rates of basic hydrolysis of N-methyl-N-(4'-nitrophenyl)octanamide and N,4-dimethyl-N- (3'-nitrophenyl)benzamide in the presence of cetyltrimethylammonium fluoride and acetate and the SNAr reactions of sodium nitrite with 2,4-dinitrofluorobenzene and 1-chloro-2,4-dinitrobenzene in the presence of cetyltrimethylammonium fluoride have been measured and compared to the rate in the presence of cetyltrimethylammonium bromide. The identity of the micellar counter ion (i.e. fluoride, acetate or bromide) has only a small effect on the rate of reaction despite quite substantial differences in exchange constants for the appropriate nucleophile/counter ion pairs; this is explained by a considerable amount of reaction between substrate molecules in the micellar pseudophase and the nucleophile in the aqueous intermicellar phase.


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