Micellar Sodium Dodecyl Sulfate Research Articles

A kinetic approach for the homogeneous reaction between N,N′propylenebis (salicylideneiminato)manganese(III) complex and hydrogen peroxide in aqueous solution

The kinetics of the homogeneous reaction between the [Mn III(saltm)Br] complex [saltm: N,N′-bis (salicylidene) propylenediamine] and hydrogen peroxide was studied in the pH range 5.05–7.29 in both aqueous and micellar sodium dodecyl sulphate solution. The reaction showed a first-order dependence in both the hydrogen peroxide and the complex. The rate of reaction was decreased with increasing acidity of the medium, as well as with increasing the concentration of the surfactant. The second-order rate constants and the activation parameters were evaluated. A mechanism involving manganese-(IV) and a peroxo-intermediate is proposed with the subsequent release of OH radicals as the rate-determining step.

A laser flash photolysis study of magnetic field effects on the hydrogen abstraction reaction of xanthone from xanthene in micellar solution

Abstract Excited triplet xanthone abstracts hydrogen from xanthene in sodium dodecyl sulphate micellar solution. The absorption intensity of the generated xanthenyl radicals increases anomalously in the presence of a magnetic field (less than 0.6 T)). The magnetic field effect is interpreted in terms of the radical pair mechanism. This anomaly can be attributed ti bimolecular reaction processes peculiar to micellar solution.

Micellar effect of ionic surfactants in the reaction ofo-dimethylaminomethylphenol withp-nitrophenyl diphenyl phosphate

The effect of cetylpyridinium bromide (CPB) and sodium dodecyl sulphate (SDS) on the direction and the rate of the reaction ofo-dimethylaminomethylphenol (MP) withp-nitrophenyl diphenyl phosphate (1) has been studied by31P NMR and spectrophotometry. It was shown that the reaction of MP with1 proceeds in two steps both with and without the surfactant. The product of transesterification is formed in the first step. The second step is hydrolysis catalyzed by the aminomethyl group yielding equal amounts of diphenyl phosphate ando-dimethylaminomethyl phenyl phosphate. The reaction of MP with1 is catalyzed by CPB and inhibited by SDS. The ratio between the rates of the first and the second stages changes in the presence of surfactant. The parameters of the reaction of MP with1 inhibited by micellar SDS were calculated.

The Modern Student Laboratory: Luminescent Characterization of Sodium Dodecyl Sulfate Micellar Solution Properties

ADVERTISEMENT RETURN TO ISSUEPREVLab-ExptNEXTThe Modern Student Laboratory: Luminescent Characterization of Sodium Dodecyl Sulfate Micellar Solution PropertiesKeith Goodling , Kim Johnson , Lee Lefkowitz , and Brian Wesley Williams Cite this: J. Chem. Educ. 1994, 71, 1, A8Publication Date (Print):January 1, 1994Publication History Received3 August 2009Published online1 January 1994Published inissue 1 January 1994https://doi.org/10.1021/ed071pA8RIGHTS & PERMISSIONSArticle Views553Altmetric-Citations23LEARN 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 (4 MB) Get e-Alerts Get e-Alerts

Influence of Large Magnetic Fields on the Dynamic Behavior of a Radical Pair Produced by Photoreduction of Benzophenone in a Micellar Solution

Abstract The photochemical reaction of benzophenone in a micellar sodium dodecylsulfate solution was investigated under magnetic fields of 0–10 T. The decrease of decay rate of the ketyl radical and the increase of the yield of the escaped radical were saturated around 2 T. The contribution of the Δg mechanism was not observed below 10 T since the Δg value is very small for this system.

Correlations between solvent polarity scales and electron transfer kinetics and an application to micellar media

Correlations of a series of solvent polarity scales with apparent standard heterogeneous rate constants k′ for electro-oxidation of ferrocene at Pt in 16 solvents covering a wide range of properties were evaluated. Single-parameter scales, including the dielectric continuum model, gave poor correlations. The best correlation was found for the Taft model, which accounts for solvent polarizability and hydrogen bond donor and acceptor properties. Correlations with Taft parameters were used for comparison with electron transfer (ET) rates of ferrocene in micellar solutions. ET rates for ferrocene in cetyltrimethylammonium (CTAB) and sodium dodecylsulphate (SDS) micelles were slightly smaller than in alcohols and much smaller than predicted for water by using Taft coefficients. The ET rate in micellar SDS was somewhat smaller than in CTAB. If, as a first approximation, equal ET distances are assumed, results suggest apparent average microenvironments for ferrocene during ET in aqueous micellar CTAB and SDS that are more polar than in many apolar solvents, but less polar than in water.

Laser flash photolysis studies of magnetic field effects on the hydrogen abstraction reaction of quinoline in micellar solution

The excited triplet quinoline undergoes a hydrogen abstraction reaction from xanthene in sodium dodecyl sulfate micellar solution. The absorption intensity of a generated xanthenyl radical increases anomalously in the presence of magnetic fields (<0.6 T). The magnetic field effects are interpreted in terms of the radical pair mechanism. The anomaly may be attributable to the slow abstraction rate of the excited triplet quinoline and to the stability of escape radicals in micellar solution. The effects on the hydrogen abstraction of other aza-aromatics are also discussed.

Mixed micelle of cholinergic anabaseine with sodium dodecyl sulfate: novel determination of the binding constants

Anabaseine (3,4,5,6-tetrahydro-2,3'-bipyridine) when added to aqueous (D 2 O) sodium dodecyl sulfate (SDS) binds to micellar SDS and undergoes a change in the position of its ring-chain hydrolysis equilibrium constant, easily followed by 1 H NMR. Micellized open-chain amino ketone (AK-SDS) is favored over micellized cyclic imine (Im-SDS), both present as their monocations. Binding constants for both are derived in a novel way from changes in the ratio of the two components as a function of the SDS concentration

The photochemistry of EDA complexes in micellar solutions. II. The stilbene–methylviologen system in the presence of oxygen

The photolyses of electron donor–acceptor (EDA) complexes formed between both cis-stilbene (cS) and trans-stilbene (tS) as donors and mefhylviologen (MV+2) as acceptor have been carried out in homogeneous ethanolic and in micellar sodium dodecyl sulfate (SDS) solutions, in the presence of oxygen. The stilbene loss quantum yields (Φ−S) have been determined in both media. Quantum yields were observed to be dependent upon methylviologen concentration and the acidity of media. A reaction scheme is proposed, which accounts for experimental results and can be related to the photochemistry of MV+2 and its cation radical MV•+. Key words: EDA complexes, micelles, methyl viologen, stilbene.

Micelle-Enhanced Lucigenin Chemiluminescence for the Determination of Catecholamines

Aqueous solutions of cationic micellar hexadecyltrimethylammonium hydroxide (CTAOH) and nonionic micellar polyoxyethylene(23) dodecanol enhanced the intensity of maximum chemiluminescence (CL) light emission from the reaction of 10,10'-dimethyl-9,9'-biacridinium dinitrate (lucigenin) with catecholamines. In contrast, a lowering of the CL emission was observed in the presence of anionic micellar sodium dodecylsulfate. The best sensitivity was achieved in micellar CTAOH: logarithmic calibration curves of adrenaline, dopamine and noradrenaline were linear over the range from the detection limit of 1×10 -8 , 3×10 7 and 5×10 -7 and 5×10 -7 M up to 1×10 -4 M, respectively. In the presence of micellar CTAOH, improvements in the sensitivity by factors of 1.6−10 were observed relative to that in water. The relative standard deviation was 2,5% in the micellar media

Hydrolysis of bis(chloromethyl)phosphonic acid p-nitroanilide in aqueous micellar surfactant solutions

The hydrolysis of bis(chloromethyl)phosphonic acid p-nitroanilide has been studied in the pH range 6.86–13.0 and the effects of ionic surfactant micelles on this process have also been examined. The nature of the micellar effects of cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) on this reaction lead us to conclude that both the neutral and anionic forms of the substrate are reactive, and that in the range of pH > pKa hydrolysis of the ionic form of the anilide predominates, while at pH < pKa the reaction of the neutral form is predominant. The binding constants for both the neutral and anionic forms of bis(chloromethyl)phosphonic acid p-nitroanilide in micellar CTAB and SDS solutions have been determined using a kinetic method, as well as by measuring the changes in the acid-base properties of the substrate resulting from the influence of micelles.

Kinetics and thermodynamics of the structural transformations of thiamine in aqueous media. Part 5. Interaction of thiamine with SDS micelles

In basic micellar sodium dodecyl sulphate (SDS) media, the transformation of thiamine into its yellow form is slowed down, but still occurs via the intramolecular attack of the 4′-amino at the 2-position of A+ to generate the σ-adduct D, with apparent second-order rate constants varying from 25.50 to 39.50 dm3 mol–1 s–1 at SDS concentrations ranging from 0.1 to 0.05 mol dm–3, respectively. This allows the measurement of the A+–micelle dissociation constant KA= 1.6 × 10–4 mol dm–3 which indicates that one micelle interacts with one thiamine molecule and that the σ-adduct formation occurs in extramicellar water with a second-order rate constant (k14= 99 dm3 mol–1 s–1) and in the micelle with a rate constant k′14= 10.9 dm3 mol–1 s–1. The fast transformation of intermediate D into J–(second-order rate constant 5.15 × 106 dm3 mol–1 s–1) competes with the interaction of D with the micelle. D seems to be instantly and partially solubilized by the SDS micelle, yielding J– after the micelle dissociates into its monomers with a relaxation time of 150 × 10–3 s. Moreover, the hydroxylation of thiamine to its pseudobase in the micellar medium is slower than in water. This transformation occurs mostly in extramicellar bulk water with a second-order rate constant k12= 19.6 dm3 mol–1 s–1. It also occurs in the micelle where it is considerably retarded with an endomicellar second-order rate constant k′12= 0.85 dm3 mol–1 s–1. D is the most hydrophobic thiamine species, its interaction with the SDS micelle may be of importance in the transport of the thiamine molecule through natural membranes.

Determination of traces of gallium in the presence of aluminium by synchronous derivative spectrofluorimetry

Gallium (2–100 ng ml −1) is determined in the presence of ⩽500-fold amounts (by weight) of aluminium by using synchronous first- or second-derivative spectrofluorimetry. The fluorescence of the gallium chelate with 1-(2-pyridylazo)-2-naphthol is greatly enhanced compared to that of the aluminium chelate in micellar sodium dodecyl sulphate solutions. The limit of detection is about 0.6 ng ml −1.

Room temperature luminescence of a retinal complex of cyclodextrin

Retinal, which is normally insoluble in an aqueous medium and not fluorescent in solution at room temperature, emits a luminescence in the region of 450 nm, even in air-saturated aqueous solutions, when complexed to β or γ-cyclodextrin. The intensity decreases in the order β> γ and the quantum yields of luminescence are in the range 10 −3–10 −4. Further, retinal molecules in the inclusion complexes are subject to a bleaching process. Solubilization in micellar sodium dodecyl sulphate solutions also allows emission, albeit in smaller yield.

The photochemistry of electron donor–acceptor (EDA) complexes in micellar solutions. I. The stilbene–methylviologen system

The association constants for the electron donor–acceptor (EDA) complexes formed between both cis-stilbene (cS) and trans-stilbene (tS) as donors and methylviologen (MV+2) as acceptor were determined in ethanol and micellar sodium dodecyl sulfate (SDS) solutions in the range of SDS concentration 0.05–0.1 M. The values obtained in micellar solutions were much higher than those in ethanol and were heavily dependent upon SDS concentration. This effect is due to an increase in the local concentration of the reactants in the micellar pseudophase. The tS fluorescence quenching by MV+2 was also studied in the same solvent media. In ethanol, the Stern–Volmer plot was found to be linear, with quenching constant (KSV) similar to the association constant determined by the absorption method. In micellar solutions, although upward curvature of the Stern–Volmer plots was observed, a reaction scheme based on static quenching via ground state EDA complex is proposed, which explains the experimental results. Irradiation in the absorption band of the EDA complexes formed by tS or cS and MV+2 was carried out in ethanol and SDS solutions, in the absence of oxygen. Only cis–trans isomerization of cS in SDS solution was observed, with a quantum yield value of Φcis = 0.012.

The electron transfer reaction between anthraquinone sulfonate radicals and duroquinone in sodium dodecyl sulfate micellar solution: A reinvestigation

The electron transfer reaction between anthraquinone sulfonate radicals and duroquinone has been studied in aqueous and micellar (sodium dodecyl sulfate, SDS) solution using the electron pulse radiolysis technique. The forward electron transfer rate constant decreased significantly with increasing SDS concentration while the back electron transfer rate constant was independent of the SDS concentration. From these results we conclude that electron transfer occurs in the aqueous phase only. There is no evidence for intramicellar electron transfer. The measured change in the forward rate constant, between aqueous and micellar solutions, is an apparent one, reflecting the decrease of the aqueous portion of duroquinone due to micellization.

Excess enthalpies of solution of some primary and secondary alcohols in sodium dodecylsulfate micellar solutions

The exces enthalpies of solution of some primary and secondary alcohols in aqueous sodium dodecylsulfate micellar solutions were measured and the results were explained by considering the distribution of alcohols between aqueous and micellar phases. The distribution constant and the enthalpy of transfer (and the standard free energy and entropy of transfer) were obtained. The thermodynamic parameters for the transfer of secondary alcohols from the aqueous to the sodium dodecylsulfate (NaDS) micellar phase differ slightly from those of the corresponding primary alcohols. For both series of alcohols the additivity rule holds for free energies of transfer whereas enthalpies and entropies display convex curves. The present data are compared to those for the transfer of the same solutes from the aqueous to the dodecyldimethylamine oxide (DDAO) and dodecyltrimethylammonium bromide (DTAB) micellar phases. The role of the hydrophilic interactions between the OH group and the micelles' head groups is formulated. The thermodynamics of the branched methyl group were determined. Furthermore, the thermodynamics of solvation of primary alcohols in water, in NaDS micelles, and in octane have been calculated using reference states based on the assumption that the empty space around alcohols in the initial and final states is the same. It is shown that the solvation of alcohols in NaDS micellar phase is enthalpy driven and that the thermodynamic properties of solvation vs. the length of the alcohol tail is the same for water and NaDS micelles whereas it is different for octane. A possible explanation for this difference is that the alkyl chain of alcohols folds in octane.

Use of micellar mobile phases and microbore column switching for the assay of drugs in physiological fluids

The feasibility of directly assaying drugs in physiological fluids using on-line preconcentration and microbore high-performance liquid chromatography has been demonstrated. The untreated sample is injected onto a hydrophobic pre-column, using micellar sodium dodecyl sulfate (SDS) in the case of serum or phosphate buffer in the case of urine, as the load mobile phase. This traps the components of interest which are then backflushed onto a microbore analytical column using a stronger mobile phase. This procedure was then applied to diazepam in serum and phenobarbital in urine. Recovery was linear and quantitative over the range 30–3000 ng/ml for diazepam in serum and 2–200 μg/ml for phenobarbital in urine. The diazepam method was specific against caffeine and the three major metabolites of diazepam: oxazepam, temazepam, and nordiazepam. The effects of varying pre-column dimensions, pre-column loading time, and SDS concentration volume were evaluated.

ChemInform Abstract: Pressure Effects on the Fluorescence Decay of Pyrene in Micellar Solutions

The monomer fluorescence decay of pyrene was measured in sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium chloride (HDTCl) micellar solutions as a function of pressure from 0.1 to 203 MPa at 25 /sup 0/C by a single-photon-counting technique. The decay curves were analyzed successfully by a conventional fluorescence decay analysis for micellar solution over the pressure ranges examined. From the analysis, it was found that the rate constant (k/sub E/) for intramicellar excimer formation decreased significantly with increasing pressure in both micellar solutions, while the cmc and the aggregation number (N) for SDS and HDTCl micelles were found to be almost independent of pressure. The activation volumes for excimer formation were 19 and 16 cm/sup 3//mol for SDS and HDTCl micellar solutions, respectively. An attempt to obtain an activation volume for a nonionic detergent was unsuccessful because of the failure of the decay profile to fit the theoretical model. However, activation volumes for microviscosity were obtained by studying the pressure dependence of intramolecular excimer formation of a dinaphthylpropane probe. The diffusion process in micelles and microviscosities are discussed by comparing the activation volume for excimer formation with those for microviscosities determined by the pressure effect on intrmolecular excimer formation, and bymore » comparing the results with those reported in the literature for a dipyrenylpropane probe.« less

A calorimetric study of three long-chain ionic surfactants

Differential enthalpies of solution in water of crystalline sodium dodecyl sulphate (SDS), sodium p-octylbenzenesulphonate (SOBS), and hexadecyltrimethylammonium bromide (CTAB) have been measured as a function of concentration at temperatures between 25 and 50 °C. The concentration change was small in the experiments and the results give a good approximation to the partial molar enthalpy content of the surfactant in the monomer and micellar states relative to the crystalline state. The enthalpies of dissolution to give monomers showed a strong, linear increase with temperature for SDS and SOBS and a nearly linear increase for CTAB, while the enthalpy of dissolution to give micelles was constant between 25 and 50 °C for the first two surfactants and only slowly increased for CTAB. Partial molar heat capacities were derived for monomeric and micellar SDS and SOBS. The large positive partial molar heat capacities of the monomeric surfactants are characteristic for hydrophobic solutes and the large heat capacity change for micelle formation arises from the loss of hydrophobic hydration in the formation of micelles. Results of microtitration experiments at 25 ° C show that the micelle formation of CTAB is not a simple aggregation process, but indicate a secondary process taking place closely after the critical micelle concentration (CMC).