Kinetic studies of the hydrolysis of n-octylamine on the surface of a sodium dodecyl sulfate micelle by the ultrasonic absorption method

Yamashita, Teruyo; Yano, Hiroshige; Harada, Shoji; Yasunaga, Tatsuya

doi:10.1021/j150644a035

Cited by 36 publications

(20 citation statements)

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“…The extent of penetration of each cosurfactant depends on interactions between polar head groups and other chemical species, water in particular. The most likely explanation is the presence of protonated and nonprotonated amino groups in equilibria at the micellar surface (31). Although pH variations would permit the demonstration of this point, we assume a greater hydrophilicity of amino groups than hydroxyl groups, in accordance with results obtained at higher chain lengths (29).…”

Section: Fig 11supporting

confidence: 80%

Micellar Solubilization: Structural and Conformational Changes Investigated by 1H and 13C Liquid-State NMR

Alonso

Harris

Kenwright

2002

Journal of Colloid and Interface Science

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Section: Fig 11supporting

confidence: 80%

Micellar Solubilization: Structural and Conformational Changes Investigated by 1H and 13C Liquid-State NMR

Alonso

Harris

Kenwright

2002

Journal of Colloid and Interface Science

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“…This causes higher solubility of C 6 NH 2 than C 6 OH in aqueous solution, and one can expect partitioning of n-hexylamine in bulk aqueous and micellar phases in comparison to nearly total localization of 1-hexanol in the micellar phase. It was reported earlier that C 4 -C 10 NH 2 were solubilized in ionic micelles by electrostatic and hydrophobic effects with amine group left on the surface (41). Their partial dissociation into -NH 3 + and OH − (though feebly) may affect electrostatic interactions with the cationic headgroup.…”

Section: Resultsmentioning

confidence: 94%

Micellar association in simultaneous presence of organic salts/additives

Kumar

Khan

Kabir-ud-Din

2002

J Surfact & Detergents

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Viscosity measurements under Newtonian flow conditions had been performed on cetyltrimethylammonium bromide (CTAB) aqueous solutions in the combined presence of sodium salts of aromatic acids (sodium salicylate, NaSal; sodium benzoate, NaBen; sodium anthranilate, NaAn) and organic additives (1-hexanol, C 6 OH; n-hexylamine, C 6 NH 2 ) at 30°C. On addition of C 6 OH or C 6 NH 2 , the viscosity of 25 mM CTAB solution remained nearly constant without salt as well as with a lower salt concentration. This is due to low CTAB concentration which is not sufficient to produce structural changes in this concentration range of salts. However, as the salt concentration was increased further, the effect of C 6 OH/C 6 NH 2 addition was different with different salts: The viscosity first increased; then a decrease was observed with the former while with C 6 NH 2 a decrease followed by constancy appeared in plots of relative viscosities (η r ) vs. organic additive concentrations. At further higher salt concentration, the magnitude of η r was much higher. The viscosity increase is explained in terms of micellar growth and the decrease in terms of swollen micelle formation (due to interior solubilization of organic additive) or micellar disintegration (due to formation of water + additive pseudophase).Paper no. S1267 in JSD 5, 55-59 (January 2002).Numerous studies have been carried out on the effect of salts (1-3) and organic additives (4-6) on the micellar structural transitions in aqueous medium. Recently, we reported a kind of "synergism" (e.g., significant increase in viscosity) in such systems when salts and organic additives are present concurrently in the micellar solutions (7-11). In these studies the nature of salts and additives was found to play a crucial role toward such synergisms.Micelles of quaternary ammonium halides [e.g., cetyltrimethylammonium bromide (CTAB)] grow from spherical to rod-shaped on the addition of different counterions (12). Halide anions associate only moderately with surfactant headgroups, and micellar growth is gradual. However, with anions that associate strongly, such as aromatic salt anions (e.g., salicylate, Sal − ), rod-shaped micelles grow rapidly even at low surfactant and salt concentrations (13), and the solutions exhibit a remarkable viscosity increase (14,15).Aqueous micelles are capable of solubilizing organic molecules with quite distinct polarities and degrees of hydrophobicity (16). The addition of different types of molecules leads to large deviations of packing parameters in micellar assembly (17). Many counterions and organic additives are strongly adsorbed at the micellar interface, and depending on the degree of penetration, this may change the mean distance between polar headgroups or may increase the volume of the micellar core. The aromatic acid counterions are most efficient with cationic micelles. 1 H nuclear magnetic resonance (NMR) studies have shown that the Sal − anion orients in such a way that the negatively charged site (COO − group) stands perpendicular to the CT...

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“…They found that the addition of octylamine to SDS micellar solutions causes the formation of mixed micelles and promotes micellar growth. The n-alkyl amines have generally been found to be solubilized in SDS by electrostatic effect and the protonated amine group is left on the surface of the micelle [23][24][25]. They also decrease the degree of counterion binding.…”

Section: Introductionmentioning

confidence: 99%

Dielectric relaxation studies of aqueous sodium dodecyl sulfate with some amines as co-solvents by time domain reflectometry technique

Kalaivani¹,

Undre²,

Sabesan³

et al. 2009

Main Group Chemistry

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Dielectric relaxation studies of aqueous sodium dodecyl sulfate with 1-butanol, benzyl alcohol, aniline, and tributylamine have been carried out for different concentrations at 303 K. Dielectric relaxation spectroscopy (DRS) is a versatile tool to monitor the dynamic process of micellar systems. The time domain dielectric data were obtained in the reflection mode in the frequency range of 10 MHz to 20 GHz using a HP54750A sampling oscilloscope and HP54754A TDR plug-in-module. The sample was held at 303 K in a standard military application (SMA) cell with an effective pin length of 1.35 mm. We have determined the relaxation time (t) using the Cole-Cole method. The relative viscosity Z r of the micellar solutions was also determined. We find that Z r increases with increasing concentrations of sodium dodecyl sulfate (SDS) and there is a non-linear increase in Z r beyond 80 mM SDS. The observed relaxation time is explained by considering the superposition of two relaxation times. One is due to the rotation of the hydrated water molecule around the micelle ions and the other due to the hydrated water squeezed in the hydrophobic interior of the micelle. Our results are explained on this basis. The results on adding amines are similar to that of adding alcohols but the interaction of the amines with the head group of the micelle is not as effective as hydroxyl group of alcohols.

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Kinetic studies of the hydrolysis of n-octylamine on the surface of a sodium dodecyl sulfate micelle by the ultrasonic absorption method

Cited by 36 publications

References 1 publication

Micellar Solubilization: Structural and Conformational Changes Investigated by 1H and 13C Liquid-State NMR

Micellar Solubilization: Structural and Conformational Changes Investigated by 1H and 13C Liquid-State NMR

Micellar association in simultaneous presence of organic salts/additives

Dielectric relaxation studies of aqueous sodium dodecyl sulfate with some amines as co-solvents by time domain reflectometry technique

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