- Properties of Dilute Aqueous Solutions of Double-Chain Surfactants, Alkyldodecyldimethylammonium Bromides with a Change in the Length of the Alkyl Chains
-
A series of cationic surfactants, dialkyldimethylammonium bromides with dodecyl as the primary alkyl chain and with methyl, ethyl, propyl, butyl, hexyl, octyl, and decyl as the second alkyl chain, as well as those with symmetric alkyl chains, dioctyl, didecyl and didodecyl ones, were synthesized, and their properties were investigated through measurements of the conductivity and air-liquid surface tension for their aqueous solutions to determine their critical micelle concentrations (cmc) and surface adsorption parameters in the formulation according to a two-dimensional lattice model in the form of the Frumkin equation. The change in cmc revealed that the free energy to transfer from water to the micelle per methylene unit is significantly small for asymmetric double-chain surfactants with a shorter second alkyl chain, and it approaches as elongating the second alkyl to those for the single-chain and symmetric double-chain surfactants. The free energy to transfer to an air-solution interface decreased approximately linearly with the total length of the hydrocarbon chains for all of the species examined. The lattice area for a symmetric double-chain surfactant molecule decreased with the length of its hydrocarbons. In a series of asymmetric ones, it showed a maximum for that with hexyl in its second alkyl.
- Hiramatsu, Koichi,Kameyama, Keiichi,Ishiguro, Ryo,Mori, Masaki,Hayase, Hisao
-
-
Read Online
- Micellar effects upon the rate of alkaline hydrolysis of triflusal
-
The rate of hydrolysis for triflusal was measured at varying concentrations of NaOH at four different temperatures (i.e. 25, 35, 45 and 55 °C). The micelles of cetyltrimethylammonium bromide (CTABr), cetyltrimethylammonium chloride (CTACl), cetyltrimethylammonium hydroxide (CTAOH) and dodecyltrimethyl-ammonium bromide (DTABr) had catalytic effect on the rate of hydrolysis. CTABr, CTACl and DTABr gave maxima like curve for the rate-[surfactant] plot while CTAOH gave plateau like curve. The anionic sodium dodecyl sulfate (SDS) did not influence the rate of alkaline hydrolysis of triflusal. The non-ionic Brij-35 inhibited the rate of the hydrolytic reaction. The catalytic effect by cationic micelles was treated by applying the pseudophase ion exchange model while the inhibitive effect by non-ionic micelles has been described by using the Poisson-Boltzmann pseudophase model. The variation in kψ with the change in [surfactant] was used to determined various kinetic parameters e.g., binding constant (Ks), and micellar rate constant (km). The addition of electrolytes decreased the reaction rate in CTABr and CTAOH micelles.
- Al-Lohedan, Hamad A.,Al-Blewi, Fawziah F.,Rafiquee,Issa, Zuheir A.
-
-
Read Online
- Striking improvement in peroxidase activity of cytochrome c by modulating hydrophobicity of surface-functionalized gold nanoparticles within cationic reverse micelles
-
This work demonstrates a remarkable enhancement in the peroxidase activity of mitochondrial membrane protein cytochrome c (cyt c) by perturbing its tertiary structure in the presence of surface-functionalised gold nanoparticles (GNPs) within cetyltrimethylammonium bromide (CTAB) reverse micelles. The loss in the tertiary structure of cyt c exposes its heme moiety (which is buried inside in the native globular form), which provides greater substrate (pyrogallol and H2O2) accessibility to the reactive heme residue. The surfactant shell of the CTAB reverse micelle in the presence of co-surfactant (n-hexanol) exerted higher crowding effects on the interfacially bound cyt c than similar anionic systems. The congested interface led to protein unfolding, which resulted in a 56-fold higher peroxidase activity of cyt c than that in water. Further perturbation in the protein's structure was achieved by doping amphiphile-capped GNPs with varying hydrophobicities in the water pool of the reverse micelles. The hydrophobic moiety on the surface of the GNPs was directed towards the interfacial region, which induced major steric strain at the interface. Consequently, interaction of the protein with the hydrophobic domain of the amphiphile further disrupted its tertiary structure, which led to better opening up of the heme residue and, thereby, superior activity of the cyt c. The cyt c activity in the reverse micelles proportionately enhanced with an increase in the hydrophobicity of the GNP-capping amphiphiles. A rigid cholesterol moiety as the hydrophobic end group of the GNP strikingly improved the cyt c activity by up to 200-fold relative to that found in aqueous buffer. Fluorescence studies with both a tryptophan residue (Trp59) of the native protein and the sodium salt of fluorescein delineated the crucial role of the hydrophobicity of the GNP-capping amphiphiles in improving the peroxidase activity of cyt c by unfolding its tertiary structure within the reverse micelles.
- Maiti, Subhabrata,Das, Krishnendu,Dutta, Sounak,Das, Prasanta Kumar
-
-
Read Online
- Effects of Single-Stranded n-Alkyl Amphiphiles on the Conformational and Dynamic Behavior of Lecithin Sonicated Bilayers and Micelles Studied by 13C NMR. A Measure of Lipid Resistance against Disruption of the Bilayer Orientation
-
The triplet fine structures in the 13C NMR spectra of carbons in the ?-position to nitrogen in several n-alkyltrimethylammonium bromides (TAB's), DMPC, and DPPC have been studied in different aggregational states under conditions of enhanced proton noise decoupling.Under the same conditions, the signals of the hydrophobic tails of the lecithins could also be studied better than hitherto, mainly by virtue of relatively narrow signals.It is shown that relatively small changes in packing and lateral motions can be detected.Intercalation of several n-alkyltrimethylammonium bromides in lecithin vesicles causes no decrease of the lipid -N+(CH3)3 mobility around the CH2-CH2 head-group linkage nor a decrease in acyl chain mobility.Moreover, no changes in acyl chain kinking are detected.On the other hand, the incorporated TAB molecules are forced by the lecithin molecules toward severely restricted head-group and tail mobilities.For those combinations of PC and TAB's where the TAB 13C NMR signals are detectable, a change in the conformational equilibrium toward more extension is found.A packing model for the incorporation of TAB's in PC vesicles is presented which probably has a rather general validity.The behavior of mixed micelles of PC's and TAB's, originating from enhancing the latter's concentration, is also described.In these systems, mobilities and chain kinking are increased with respect to the vesicular state.
- Haan, Jan W. de,Weerd, Roel J. E. M. de,Ven, Leo J. M. van de,Buck, Henk M.
-
-
Read Online
- GEMINI TYPE SURFACTANT
-
PROBLEM TO BE SOLVED: To provide a gemini type surfactant that has a novel structure and can be synthesized conveniently. SOLUTION: The present invention provides a gemini type surfactant represented by formula (1), where R1-R5 independently represent alkyl, hydroxyalkyl, aryl or the like; R is alkyl, hydroxyalkyl, aryl or the like; Y1 and Y2 independently represent alkylene; n is an integer of 2-4; A- is a counterion; where, R1-R2 and R3-R4 must be the same combination; Z is NR5 or O; R5 is an alkyl group, hydroxyalkyl, aryl or the like. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
- -
-
Paragraph 0094; 0095
(2017/05/17)
-
- Gemini type surfactant
-
PROBLEM TO BE SOLVED: To provide a gemini type surfactant being a compound having two hydrophilic groups and two hydrophobic groups that has a novel structure and can be simply synthesized. SOLUTION: The gemini type surfactant has a structure represented by formula (1). [In formula (1), R1 to R4 are each independently a 1-20C alkyl group, a 1-20C hydroxyalkyl group, a 1-20C halogenated alkyl group or a 6-20C aromatic hydrocarbon group; Z is N or O atom; Y1 and Y2 are each independently a 1-6C alkylene group; n is an integer of 0 to 2; m is 0 or 1; A- is a counter ion; and provided that any two of R1 to R5 may be bonded to each other to form a ring structure.] COPYRIGHT: (C)2015,JPOandINPIT
- -
-
Paragraph 0070
(2017/01/02)
-
- Kinetics of hydrolysis of procaine in aqueous and micellar media
-
The kinetics of alkaline hydrolysis of procaine under the pseudo-first-order condition ([OH-] a [procaine]) has been carried out. N,N-Diethylaminoethanol and p-aminobenzoate anion were obtained as the hydrolysis product. The rate of hydrolysis was found to be linearly dependent upon [NaOH]. The addition of cationic cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DDTAB) and tetradecyltrimethylammonium bromide, and anionic sodium dodecyl sulfate (SDS) micelles inhibited the rate of hydrolysis. The maximum inhibitive effect on the reaction rate was observed for SDS micelles, whereas among the cationic surfactants, CTAB inhibited most. The variation in the rate of hydrolysis of procaine in the micellar media is attributed to the orientation of a reactive molecule to the surfactant and the binding constant of procaine with micelles. The rate of hydrolysis of procaine is negligible in DDTAB micelles. The observed results in the presence of cationic micelles were treated on the basis of the pseudophase ion exchange model. The results obtained in the presence of anionic micelles were treated by the pseudophase model, and the various kinetic parameters were determined.
- Al-Blewi, Fawzia Faleh,Al-Lohedan, Hamad A.,Rafiquee,Issa, Zuheir A.
-
-
- Odd-even effect and unusual behavior of dodecyl-substituted analogue observed in the crystal structure of alkyltrimethylammonium-[Ni(dmit) 2]- salts
-
A series of [Ni(dmit)2]- (dmit: 1,3-dithiole-2- thione-4,5-dithiolato) salts of alkyltrimethylammonium (Cn: n represents the alkyl chain length; n = 3 and 518) have been prepared and analyzed by X-ray structural analysis. All complex salts have been found to be composed of alternate sheets of [Ni(dmit)2]- anions and sheets of cations with a pronounced interdigitation of the alkyl chains. However, molecular arrangement differed between (C3)[Ni(dmit)2] and other (Cn)[Ni(dmit)2] (n = 518). Adjacent cations were aligned along the long axis of [Ni(dmit)2]- anion in C3 complex salt, while in others (C5-C18 complex salts), they were aligned toward the short axis. Such a difference in arrangement arose from correlativity between the lengths of the long axis of cation and anion, namely CLCA. Furthermore, relative orientation between the alkyl chain of cation and [Ni(dmit)2]- anion differed between the odd- and even-numbered cations for C10-C18. Whereas the plane of alkyl chain for odd-numbered cation was normal to the plane of [Ni(dmit)2]- anion, that of even-numbered cation was parallel. It was also found that C12 analog behaved like odd-numbered cations. However, in C12 salt, the end methyl group of the dodecyl group adopted unusual end-gauche conformation.
- Dai, Kotaro,Nomoto, Kuniharu,Ueno, Shinji,Tomono, Kazuaki,Miyamura, Kazuo
-
experimental part
p. 312 - 319
(2011/05/13)
-
- Alkylation of ammonium salts catalyzed by imidazolium-based ionic liquid catalysts
-
Quaternary ammonium salts were synthesized from ammonium salts and dialkyl carbonates over imidazolium ionic liquid catalysts. The reaction gave almost stoichiometric amounts of the quaternary ammonium salts for halides and nitrates. It was found that the electron-donating property of the alkyl moieties of ammonium cations, the electrophilic nature of the alkyl group of the carbonate, the acidity of the acid that the anion of the ammonium salt corresponds to, and the steric hindrance of the ammonium salts and the dialkyl carbonates are the key factors that influence the yields of quaternary ammonium salts. Strong electron-donating alkyl groups on the nitrogen atom of the ammonium salt, electron-withdrawing groups on the methylene carbon of dialkyl carbonate, and weaker steric hindrance of the starting ammonium salts and dialkyl carbonates favor the alkylation reaction of ammonium salts.
- Zheng, Zhuo Qun,Wang, Jie,Wu, Ting Hua,Zhou, Xiao Ping
-
p. 1095 - 1101
(2008/03/27)
-
- Surface properties and aggregates in the mixed systems of bolaamphiphiles and their oppositely charged conventional surfactants
-
Two transition points were observed in the surface tension curves of the mixed systems of cationic bolaamphiphile BPHTAB (biphenyl-4,4′- bis(oxyhexamethylenetrimethylammonium bromide)) and its oppositely charged conventional surfactants. Transmission electron microscopy, dynamic light scattering, and isothermal titration microcalorimetric experiments demonstrated that spherical vesicles or elongated aggregates formed at the lower surfactant concentration than the corresponding critical micelle concentration (cmc), which led to the existence of two transition points in surface tension curves. Addition of 10% formamide into the mixed system broke the vesicles and elongated aggregates and made the first breaking point disappear. The biphenyl group in the BPHTAB molecule and the appropriate attractive interaction between the cationic and anionic headgroups of the surfactants had a great influence on the ability of vesicle formation and determined whether the two transition points would exist in the surface tension curve.
- Han, Feng,He, Xiao,Huang, Jianbin,Li, Ziehen,Wang, Yilin,Fu, Honglan
-
p. 5256 - 5262
(2007/10/03)
-
- Interaction of Methyl Orange with Submicellar Cationic Surfactants
-
The interaction of aqueous Methyl Orange (MO), an azo dye, with alkyltrimethylammonium and N-hexadecylpyridinium halide surfactants in submicellar concentration ranges has been investigated.The interaction gives rise to a new absorption band of MO with a maximum at ca. 370 nm, and the appearance of the new band has been attributed to change in the chromophore microenvironment in water structure enforced closely packed ion pairs of the dye with submicellar cationic surfactant.The strength of the interaction depends on the alkyl chain length of the surfactant, the surfactant head group and the counter ions.
- Dutta, Robin K.,Bhat, Subray N.
-
p. 2457 - 2460
(2007/10/02)
-
- Dentifrice containing a poly(hydroxypropyl ether) non-ionic surfactant and a specified cationic polymer
-
Dentifrice containing, in combination, (A) a poly(hydroxypropyl ether) nonionic surfactant, and (B) a cationic polymer selected from the group consisting of (i) a vinylpyrrolidone/dialkylaminoalkyl or -hydroxyalkyl acrylate or methacrylate, quaternized or nonquaternized and (ii) a cationic polysaccharide. This dentifrice is characterized by good foamability, pleasant taste and it does not attack the buccal mucosae and the gums.
- -
-
-
- Hair rinse composition
-
A hair rinse composition having improved rinsing performance and a process specified to prepare the same. The composition according to the invention comprises (A) 0.05 to 0.5 wt % of cationic surface active agent, and (B) a higher alcohol or a glycerine mono fatty acid ester having a melting point not lower than 45° C. The ingredient (B) should be contained in an amount of 3 to 15 times by weight to ingredient (A). The composition is prepared by diluting a highly concentrated emulsified product containing 0.4 to 34 wt % of ingredient (A) and (B) in total with 1 to 20 times by weight to the emulsified product of water.
- -
-
-
