N-hexadecylpyridinium Chloride Research Articles

Interaction of a pyrene-labeled cholesterol-bearing polyanion with surfactant micelles studied by fluorescence quenching

The dissociation of multipolymer aggregates of a cholesterol-bearing polyanion by surfactant micelles in water and the formation of polymer–micelle complexes were investigated using fluorescence techniques. Interchain aggregates of cholesterol residues in a random terpolymer of sodium 2-(acrylamido)-2-methylpropanesulfonate (94 mol%), cholesteryl 6-methacryloyloxyhexanoate (5 mol%), and N-(1-pyrenylmethyl)methacrylamide (1 mol%) are completely disrupted by the addition of nonionic micelles of n-dodecyl hexa(oxyethylene) glycol monoether (C 12E 6) resulting in polymer–micelle complexes. Fluorescence of pyrene labels in the terpolymer indicated that C 12E 6 micelles bind predominantly to cholesterol sites while the micelle interacts only weakly with pyrene sites. When a small amount of n-hexadecyltrimethylammonium chloride (CTAC), a cationic surfactant, was added to the C 12E 6 micelle, positively charged C 12E 6/CTAC mixed micelles bind to sulfonate sites in the terpolymer. This additional electrostatic interaction strengthens the binding of the micelle to pyrene sites as well as cholesterol sites. The pyrene–micelle interaction thus increased was investigated by steady-state and time-dependent fluorescence quenching techniques using n-hexadecylpyridinium chloride, a quencher, added to the C 12E 6/CTAC mixed micelle. Fluorescence quenching data for varying micelle charge densities (i.e. the mole fraction of CTAC ( Y) in the mixed micelle) were analyzed using a kinetic model. Results made it clear that the residence time of the mixed micelle on the pyrene site increases with increasing Y. A long residence time of ca. 19 μs was observed at Y=0.09 as a result of an interplay of interaction of the micelle charge with the polymer charge and hydrophobic interaction of the micelle with mainly cholesterol sites.

Fluorescence Quenching Studies of Micellization and Solubilization in Fluorocarbon−Hydrocarbon Surfactant Mixtures

Time-resolved fluorescence quenching studies of nonionic, anionic, and cationic micelles have been performed to compare two surfactant quenchers, a fluorocarbon surfactant quencher, N-(1,1,2,2-tetrahydroperfluorodecanyl)pyridinium chloride (HFDePC) and a hydrocarbon quencher of similar hydrophobicity, C16PC, N-hexadecylpyridinium chloride. The concentration dependence of the apparent aggregation numbers informs on the interaction between the surfactants, which always was repulsive for the fluorocarbon quencher in hydrocarbon micelles, except for the case with a nonionic micelle, where the effectively attractive electrostatic interaction dominated at low ionic strength. The simple theory (Almgren, M.; Hansson, P.; Wang, K. Langmuir 1996, 12, 3855) suggests that the interaction parameter from the slope of the apparent aggregation number versus mole fraction quencher should be the same as the interaction parameter describing the change of the critical micelle concentration with composition according to regular solution theory (Rubingh, D. H. In Solution Chemistry of Surfactants; Mittal, K. L., Ed.; Plenum Press: New York, 1979; Vol. 1, p 337). The results show that it is not so; not even the sign of the interaction parameter is always the same. The reasons for the difference are discussed. For the weight average aggregation number, obtained by extrapolation to zero quencher concentration, the two quenchers gave results within about 10% for a given surfactant; the values with the fluorocarbon quencher seemed to be systematically lower, as if the aromatic probe strongly avoided micelles containing fluorocarbon quenchers. From solubility studies, pyrene was found to prefer a C16TAC micelle over a HFDePC micelle by a factor of 60. The preference of pyrene for micelles without fluorocarbon surfactants was utilized to show the demixing into fluorocarbon-rich and hydrocarbon-rich micelles in a mixture of lithium perfluorononanoate and lithium dodecyl sulfate and in cetyltrimethylammonium chloride and HFDePC.

Picosecond studies on the electron transfer from pyrene and perylene excited singlet states to N-hexadecyl pyridinium chloride

Picosecond laser flash photolysis studies have been carried out on two aromatic solutes, pyrene (Py) and perylene (Pe), in methanolic and aqueous micellar solutions of a cationic surfactant, hexadecyl pyridium chloride (CPC) on excitation at 355 nm. In methanolic solutions, the addition of CPC quenches the singlet state of the aromatics giving rise to cation radicals, Py +· and Pe +·, respectively. The cation radicals either decay by geminate recombination or escape in the bulk solution phase in ≈ 1000 ps. In aqueous micellar solutions of CPC, only Py +· is observed, while for Pe, initially both the singlet and the cation radical are observed immediately after the 35 ps laser pulse. The observed decay kinetics are explained in terms of electron transfer and geminate recombination processes.

Solubilization of Trichloroethylene by N-Hexadecylpyridinium Chloride Micelles

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolubilization of Trichloroethylene by N-Hexadecylpyridinium Chloride MicellesHirotaka Uchiyama, Edwin E. Tucker, Sherril D. Christian, and John F. ScamehornCite this: J. Phys. Chem. 1994, 98, 6, 1714–1718Publication Date (Print):February 1, 1994Publication History Published online1 May 2002Published inissue 1 February 1994https://doi.org/10.1021/j100057a027RIGHTS & PERMISSIONSArticle Views75Altmetric-Citations15LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (517 KB) Get e-Alerts

Association of neutral red with micelles and its effect on the pKa

The interactions of neutral red with cationic surfactants, viz., N-hexadecylpyridinium chloride and alkyltrimethylammonium bromides; a nonionic surfactant, viz., Triton X100; and an anionic surfactant, viz., sodium dodecyl sulfate, were investigated spectroscopically. The equilibrium constants for the association of the indicator with the micelles were determined from the apparent association constants at constant pH at 298 K. The effects of the indicator-micelle association on the apparent pKa of the indicator in aqueous surfactant solutions are discussed. It was shown that the apparent pKa of the indicator in cationic surfactant solution can be predicted from knowledge of the indicator-micelle association constant.

Spectrophotometric Determination of Gadolinium(III) With O-Hydroxyhydroqoinonephthalein in Mixed Micelles of N-Hexadecylpyridinilm Chloride and Brij 35

Abstract A sensitive, simple and selective spectrophotometric method for the determination of gadolinium(III) is proposed using o-hydroxyhydroquinonephthalein(Qnph), by analogy with phenylfl-uorone(Phfl), in the presence of N-hexadecylpyridinium chlo-ride(HPC)-Brij 35 mixed surfactants. The calibration curve is rectilinear in the range of 0 – 16.0 μg per 10 ml at 590 nm with an apparent absorption coefficient(∊) of 1.2 × 105 1 cm−1 mol−1 and Sandell sensitivity of 0.0013 μg/cm2 gado-linium(III).

Effects of an anionic polyelectrolyte on the solubilization of mono- and dichlorophenols by aqueous solutions of N-hexadecylpyridinium chloride

Effects of an anionic polyelectrolyte on the solubilization of mono- and dichlorophenols by aqueous solutions of N-hexadecylpyridinium chloride

Substituent group effects on the solubilization of polar aromatic solutes (phenols, anilines, and benzaldehydes) by N-hexadecylpyridinium chloride

Solubilization isotherms of polar aromatic solutes (phenols, anilines, and benzaldehydes) in N-hexadecylpyridinium chloride micelles have been determined at 25{degree}C by using the semiequilibrium dialysis method. Effects of various substituent groups (H, F, Cl, Br, CH{sub 3}O, NO{sub 2}, CH{sub 3}, Et, i-Pr, and CF{sub 3}) have been studied for the solubilization of phenol, aniline, and benzaldehyde derivatives in aqueous solutions of the surfactant. Both hydrophobic and electrostatic effects are shown to be important in influencing the solubilization behavior. The simple expression, K = K{sub 0}(1 {minus} BX){sup 2}, is used to correlate the solubilization equilibrium constant (K) with the mole fraction of solute in the micelles (X). Linear free energy relationships can be used to correlate the solubilization results for the different classes of compounds.

Fluorescence quenching of pyrene by N-hexadecyl pyridinium chloride in mixed anionic micelles

A study of the fluorescence quenching of pyrene by N-hexadecyl pyridinium chloride in mixed micelles of sodium decyl and dodecyl sulphate, using a transient-state time-resolved fluorescence technique, enabled the determination of aggregation numbers and micellar volumes. The former vary between 49 to 65 and the latter between 16.6 and 20 dm3 mol–1 as the mole fraction of sodium dodecyl sulphate ranges from 0 to 1. A bimolecular rate constant to account for the electron transfer interaction was determined as 1.7 × 109 dm3 mol–1 s–1, regardless of the micellar size.

Zero-Order and Third-Derivative Spectrophotometric Determination of Iron(III) with 4-(2-Pyridylazo)-Resorcinol in the Presence of N-Hexadecylpyridinium Chloride

Abstract The complex formation reaction between iron(III) and 4-(2-pyridylazo) resorcinol(PAR) in the presence of various water soluble surfactants((N-hexadecylpyridinium chloride (HPC), poly(vinylalcohol)(PVA), sodium dodecylsulfate(SDS), sodium N-lauroylsarcosine(SL)) alone or in combination at weakly acidic media was systematically investigated. An improved and more sensitive spectrophotometric method for the determination of iron was proposed by zero-order and third-derivative spectrophotometry using the PAR-iron(III)-HPC ternary complex system at about pH 5.2. The calibration curve was rectilinear in the ranges of 0 – 15.0 μg iron(III) in a final 10-ml on the zero-order spectrophotometry. Also, upon the third-derivative spectrophotometry, Beer's law was obeyed in the range of 0 – 8.0 μg iron(III)/10 ml by measuring the distance between the absorbance peak(λ1 = 527 nm) and the valley (λ2 = 560 nm). The apparent molar absorptivity was 4.8 × 104 1 mol−1 cm−1 in zero-order spectrophotometry, and 1.36 × 105 mol−1 cm−1 in third-derivative spectrophotometry. The effect of foreign ions was decreased within ½ – ¼-fold in comparison with the method in the presence of PVA without HPC. Especially, the third-derivative spectrophotometric method was sensitive and selective, and made possible to assay mixed sample solution containing iron(III) and copper(II), etc.

Color Reaction Between 4-(2-Pyridylazo)Resorcinol and Mercury (II) in the Presence of Surfactant, and Improved Spectrophotometric Determinations of Mercury(II) and Cyanide Ion with its Coloring

Abstract The reactions among 4-(2-pyridylazo)resorcinol (PAR), mercury(II) and/or cyanide ion in the presence of water soluble surfactants alone or combination were systematically investigated at about pH 9. The spectrophotometric determinations of mercury(II) and cyanide ion were investigated by using the PAR-mercury(II)-HPC complex (3:2:2 molar ratio) in the presence of N-hexadecylpyridinium chloride (HPC) alone; calibration graphs were rectilinear in the ranges of 0 – 40 μg mercury(II) and 0 –10 μg cyanide ion in a final 10 ml with the apparent molar absorptivities of 5.9 × 104 for mercury(II) and 2.5 × 104 1 mol−1 cm−1 for cyanide ion at 590 nm. The proposed method had advantages—rapidity, simplicity without solvent extraction, and sensitivity in comparison with reported solvent extraction methods. The interference of foreign ions decreased 1/2–l//4-fold compared with that in the presence of non-ionic surfactant alone.

Xylenol Orange, Zirconium(IV) and Fluoride Color Reaction in Mixed Micelles of N-Hexadecylpyridinium Chloride and Brij 35, and Its Analytical Application1

Abstract The color reaction between Xylenol orange (XO), zirconium (IV) and fluoride ions in the presence of various surfactants alone or in combination was studied at various pH. The XO -zirconium)IV)-fluoride ion ternary complex in mixed micellar media containing a low concentration of N-hexadecylpyridinium chloride (HPC) as a cationic surfactant and large amounts of (poly{oxyethylene)dodecyl ether (Brij 35) as a nonionic surfactant at weakly acidic media was found to be the most stable, and showed a remarkable bathochromic shift and clear contrast against a reagent blank. The maximum absorbance was at 600 nm in the mixed micellar media at pH 3.5, and the apparent molar absorptivities at 600 nm were 7.0 × 104 1 mol−1 cm−1 for zirconium(IV) and 1.4 × 104 1 mol−1 cm−1 for fluoride ion. The calibration curves covered the ranges of 0.5 ∼ 20.0 μg/10 ml zirconium! IV) and 0 ∼ 20.0 μg/10 ml fluoride ion with the Sandell sensitivities being 0.0013 μg/cm2 for zirconium(IV) and 0.0016 μg/cm2 for fluoride ion.

Spectrophotometric Study of the Effect of Cationic Micelles on the Reaction Between Gallein and Th(IV)

The acid dissociation equilibria of gallein (pyrogallolphthalein, gall), as a xanthene dye, in the presence of various surfactants--cationic, anionic, nonionic, are discussed. The coexistence of a cationic surfactant, such as hexadecyltrimethylammonium chloride (HTAC) slightly enhanced the acid dissociation, and led to a chromogenic reaction between metal ions and gall in weakly acidic media. The ternary complex between gall and Th(IV), in weakly acidic media and in the presence of N-hexadecylpyridinium chloride(HPC), was very stable with definitive spectra. However, the complex was easily decomposed in proportion to the concentration of citrate ion. Therefore, simple and rapid spectrophotometric methods for the determination of Th(IV) and citrate ion were respectively established, by using the gall-Th(IV)-HPC ternary complex in the cationic surfactant micelle. Beer's law was obeyed over the range 0 to 90..mu..g of Th(IV) and 12 to 35..mu..g of citrate ion, in a final volume of 10 ml. The Sandell sensitivities were estimated to be 0.0013 ..mu..g/cm/sup 2/ Th(IV) and 0.0005 ..mu..g/cm/sup 2/ citrate ion at 600 nm. The analytical procedures were simple and did not require any organic solvent extraction.

Improved Spectrophotometric Determinations of Cobalt(II) and Nickel(II) with Zincon in the Surfactants Micellar

Abstract Reactions between Zincon and cobalt(II) in the presence of N-hexadecylpyridinium chloride (cationic surfactant), and between Zincon and nickel(II) in the presence of poly(vinyl alcohol) (nonionic surfactant) are discussed in terms of the development of simple, sensitive and improved spectrophotometric determinations of cobalt(II) and nickel(II). The calibration graphs were rectilinear in the ranges 0–2.2 μg 10 cm−3 cobalt(II) with a Sandell sensitivity of 0.00015 μg cm−2 at 550 nm and 0–42.0 μg 10 cm3 nickel(II) with that of 0.0047 μg cm−2 nickel(II) at 470 nm. The proposed methods were relatively sensitive in comparison with the methods in the absence of surfactants with apparent molar extinctions of 4.6×105 for cobalt(II) and 2.4×104 dm3 mol−1 cm−1 for nickel(II). Separative assays of cobalt(II) and various metals (nickel(II), zinc(II), copper(II), and iron(III)) were possible by selections of analytical wavelengths, respectively.

Calculation of organic solute and surfactant activities from solubilization data

Vapor pressure methods developed in our laboratory have produced highly precise solubilization data relating to the interaction of volatile organic compounds with nonvolatile solutes, including ionic surfactants in aqueous solution. By using a computational method similar to one developed previously we can infer the change in activity of the surfactant from solubilization isotherms. The technique, employing a form of the Gibbs-Duhem equation, yields values of the surfactant activity or monomer concentration, independent of any particular mass action model. Results show that surfactant activities inferred from benzene vapor pressure data for aqueous solutions of sodium n-octylsulfate are nearly equal to those calculated previously with a mass-action model. New activity coefficient results (obtained by vapor pressure and vapor pressure osmometry methods) are reported for both the organic solute and the surfactant in several systems containing organic compounds dissolved in aqueous n-hexadecylpyridinium chloride.

Use of the semi-equilibrium dialysis method in studying the thermodynamics of solubilization of organic compounds in surfactant micelles. Systemn-hexadecylpyridinium chloride-phenol-water

The semi-equilibrium dialysis method has been used to infer solubilization equilibrium constants or, alternatively, activity coefficients of solutes solubilized into micelles of aqueous surfactant solutions. Methods are described for inferring the concentrationa of monomers of the organic solute and of the surfactant on both sides of the dialysis membrane, under conditions where the organic solute is in equilibrium with both the high-concentration (retentate) and low-concentration (permeate) solutions. By using a form of the Gibbs-Duhem equation, activity coefficients of both phenol (the solubilizate) and n-hexadecylpyridinium chloride (the surfactant) are obtained for aqueous solutions at 25°C throughout a wide range of relative compositions of surfactant and solubilizate within the micelle. The apparent solubilization constant, K=[solubilized phenol]/([monomeric phenol][micellar surfactant]), is found to decrease significantly as the mole fraction of phenol in the micelle increases.

Reactivity and equilibriums in ionic micellar solution. Part 8. Models for specific counterion effects on the incorporation of charged amphiphilic substrates into like-charged ionic micelles

Data for the quenching of the fluorescence of two anthracene-derived amphiphilic fluorescence probes (ethyldimethyl-(I) and trimethyl(3-(9-anthracenyl)propyl)ammonium bromide (II)) in aqueous micellar solutions of the quencher detergents N-hexadecylpyridinium chloride (HPCl), bromide (HPBr), and nitrate (HPNO/sub 3/) are analyzed in terms of a photophysical model which assumes static quenching of the micelle-incorporated probe and dynamic quenching of the residual fluorescence of the unincorporated probe by free detergent monomer and free counterions. This analysis provides values for the ground-state probe incorporation coefficient K/sub s/ which are compatible with independent estimates based on the quenching of the emission of the micelle-excluded Ru(bpy)/sub 3//sup 2 +/ ion by I under the same conditions. The results show that the incorporation coefficient is sensitive to the concentration of detergent and added salt present. 4 figures, 2 tables.