The Preparation of Long Chain N-Acylamino Acids

Jungermann, Eric; Gerecht, J. Fred; Krems, Irving J.

doi:10.1021/ja01582a049

Cited by 78 publications

(34 citation statements)

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“…These did not show any minimum in surface tension-concentration plot and provided a well-defined breakpoint at CMC values which agreed with those reported in literature (Table 1). Sodium tetradecylsarcosinate (STSa) was prepared in the laboratory as reported elsewhere (21), recrystallized twice from ethanol/methanol mixture, and stored in vacuum. Triple-distilled water (conductivity ≅ 10 −6 S cm − using triple-distilled water.…”

Section: Methodsmentioning

confidence: 99%

Mixed micelles of some anionic‐anionic, cationic‐cationic, and ionic‐nonionic surfactants in aqueous media

Vora

George

Desai

et al. 1999

J Surfact & Detergents

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Critical micelle concentrations (CMC) were obtained from tensiometric studies on several binary surfactant mixtures (anionic-anionic, cationic-cationic, anionic-nonionic, and cationic-nonionic) in water at different mole fractions (0-1). The composition of mixed micelles and the interaction parameter β, evaluated from the CMC data for different systems using Rubingh's theory, are discussed. Marked interaction is observed for ionic-nonionic systems, whereas it is weak in the case of similarly charged surfactants. The influence of counterion valence in the formation of mixed micelles was investigated, and results suggest that in similarly charged surfactant mixtures, the degree of counterion binding does have a major role in deciding the extent of interactions. Salt addition reveals a weakening of interactions in ionic-nonionic systems, and this is attributed to head group charge neutralization and dehydration of the ethylene oxide units of the nonionic surfactants. Cloud point and viscosity data on these systems support the observation.Paper no. S1110 in JSD 2, 213-221 (April 1999). KEY WORDS:Cloud point, mixed micelles, sphere-to-rod transitions, synergism.Adsorption characteristics of surfactants from solution onto different interfaces and the propensity of surfactants to form micelles and mesomorphic phases are useful in almost all practical applications such as foaming, dispersing, solubilizing, wetting, emulsifying and cleansing action (1,2). Owing to their improved action over single pure surfactants, mixed systems like surfactant/surfactant (3,4) or polymer/surfactant (5) are often used in formulations of finished products. It is therefore important to investigate the nature of interactions and factors affecting them in aqueous media so as to understand how these control the product performance. The tendency of different surfactants to form mixed micelles is governed by their attractive (synergistic) or repulsive (antagonistic) interactions and is often explained from the β parameter estimated using Rubingh ' s regular solution theory (6). Extensive studies have been carried out on various mixed surfactant systems like anionic-anionic (7-9), cationic-cationic (10-12), anionic-nonionic (13-15), cationic-nonionic (16,17), cationicanionic (18,19), and nonionic-nonionic (20). Considerable interaction has been reported for ionic-nonionic systems, whereas weak or negligible interaction has been observed for similarly charged surfactants. Interaction between anionic-cationic surfactants is generally very strong but such systems often lead to precipitation/coacervation as a result of the coulombic interactions between oppositely charged species. We report in this paper tensiometric studies on eight mixed systems where results are explained in terms of the β parameter. Critical micelle concentration (CMC) data for some anionic-anionic and cationic-cationic systems from the literature (11,12) are analyzed to compute a β parameter so as to investigate the role of counterion valence in the nature and strength of inte...

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Section: Methodsmentioning

confidence: 99%

Mixed micelles of some anionic‐anionic, cationic‐cationic, and ionic‐nonionic surfactants in aqueous media

Vora

George

Desai

et al. 1999

J Surfact & Detergents

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“…' The N-dodecanoylalanine used in this study was prepared from commercially provided I and d.1-alanine by reaction with dodecanoyl chloride, as has been described (12), and that procedure differs little from the procedure utilized here. The purity of the amidc was monitored by "C magnetic resonance, which indicated that several recrystallizations from petroleum ether (60-80) were required in order to remove dodecanoic acid.…”

Section: Methodsmentioning

confidence: 99%

A laser diffraction and nuclear magnetic resonance investigation of the cholesteric potassium N-dodecanoylalaninate mesophase system

Radley¹,

Tracey²

1985

Can. J. Chem.

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KEITH RADLEY and ALAN S. TRACEY. Can. J. Chem. 63, 95 (1985). Nematic and twisted nematic mesophases have been prepared from various mixtures of potassium N-dodecanoyl-I-alaninate and its racemate. The induced pitch was determined as a function of optical purity as werc nmr spectra from a variety of additives including several inorganic salts and d,l-alanine. Dipolar couplings from the CHCHl moiety of the alaninate headgroup were studied, as were quadrupole splittings from the N-D of the amido group and the DZO of the water. It was proposed that with development of cholesteric behaviour on proceeding in a stepwise fashion from the d,l to I amphiphile, the individual disk-like micelles twisted into a chiral shape, then aggregated to form domain-like structures. The major axis of these aggregates is the axis along which the helix propagates and this local axis serves as the director axis for the aggregates. The individual aggregates reorient as a unit when placed in the magnetic field of an nmr spectrometer. As a consequence of this, the diamagnetic anisotropy of the mesophase prepared from the I amphiphile is positive in sign while that of the d,l analogue is negative. Despite this observed change in diamagnetic anisotropy, the alignment of the individual micelles is not different for the chiral and racemic materials.KEITH RADLEY et ALAN S. TRACEY. Can. J . Chem. 63, 95 (1985).On a prCpart des mCsophases nCmatiques et nematiques croistes a partir de divers mtlanges de N-dodtcanoyl I-alaninate de potassium et de son rackmate. On a dktermint le pas induit en fonction de la purett optique ainsi que les spectres rmn obtenus par I'addition de divers produits incluant plusieurs sels inorganiques et la d.1-alanine. On a ktudiC les couplages dipolaires de la portion CHCH3 de I'alaninate de t&te ainsi que les couplages quadrupolaires N-D du groupe amido et du D1O de I'eau. II a ttt propost que, si on dkveloppe le caractkre cholestCrique lorsqu'on procede par Ctape de I'amphiphile d.1 vcrs le I, les micelles individuelles en forme de disques se croisent pour prendre unc forme chirale et elles s'agglutinent ensuite pour former des structures en forme de domaines. L'axe principal de ces aggrtgats est I'axe le long duquel I'htlice se propage et cet axe local sert d'axe directeur pour ces aggrtgats. Les aggrtgats individuels se rtorientent sous forme d'unite lorsqu'ils sont placts dans le champ magnCtique d'un spectromktre rmn. A cause de cette reorientation, I'anisotropie diamagnitique de la mksophase prCparte a partir du I-amphiphile est de signe positif alors que celle de I'analogue d,l est nkgative. En dipit de ce changement observt dans I'anisotropie diamagnktique, il n'y a pas de diffirence dans I'alignement des micelles individuelles des substances chirales et ractmiques.[Traduit par le journal]

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“…Other N -palmitoyl amino acids resulted in white precipitates. All the compounds were characterized by IR spectroscopy and 1 H NMR, the data being in line with those given in the bibliography [48][49][50]. The purity was controlled by thin layer chromatography.…”

Section: Methodsmentioning

confidence: 68%

Self-assembly properties of some chiral N-palmitoyl amino acid surfactants in aqueous solution

Gerova

Rodrigues

Lamère

et al. 2008

Journal of Colloid and Interface Science

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The Preparation of Long Chain N-Acylamino Acids

Cited by 78 publications

References 0 publications

Mixed micelles of some anionic‐anionic, cationic‐cationic, and ionic‐nonionic surfactants in aqueous media

Mixed micelles of some anionic‐anionic, cationic‐cationic, and ionic‐nonionic surfactants in aqueous media

A laser diffraction and nuclear magnetic resonance investigation of the cholesteric potassium N-dodecanoylalaninate mesophase system

Self-assembly properties of some chiral N-palmitoyl amino acid surfactants in aqueous solution

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