Sodium Decyl Sulfate Research Articles

Photoprotolytic dissociation in micellar solutions

Abstract Rate constants of proton transfer of several hydroxyaromatic compounds in non-ionic, anionic and cationic surfactant solutions are determined. The data are extrapolated to the limiting case of complete solubilization. The photoprotolytic dissociation rate constants in non-ionic micelles of Brij-56 decrease approximately by an orde of magnitude, and are 15, 30 and 60 times lower in sodium decylsulphate, sodium dodecylsulphate and sodium hexadecylsulphate respectively and change little in cetyltri-methylammonium bromide micelles in comparison with aqueous solutions. Photoprotolytic dissociation does not need the exit of the reactant molecules from micelles and excited products are formed initially within the micellar phase. Rate constants of the exit of the anions thus formed from the micelles are estimated. The exit from cationic and non-ionic micelles is much slower than deactivation of the excited anions but is quite effective in anionic micelles. Exit rate constants increase with the growth of the surfactant hydrocarbon chain.

Deformation of cylinders in the hexagonal phase of sodium decyl sulphate/decanol/water on the introduction of decanol

Abstract X-ray scattering studies show that aggregates of amphiphilic molecules in the hexagonal phase of the binary system sodium decyl sulphate/water are infinite cylinders whose radius is very close to that of the extended molecule. When sodium decyl sulphate molecules are progressively substituted by decanol molecules the phase remains hexagonal, up to a decanol/soap molar ratio of 0.15, but the radius of its cylinders becomes larger than the molecular length. We have developed specific experiments to investigate this growth and see if it is isotropic or anisotropic. We have focused our attention on the evolution of the configuration of soap and decanol molecules within the aggregates. Neutron scattering experiments show that the two molecules do not distribute themselves uniformly and D.M.R. measurements show that they stay anchored at the amphiphile/water interface by their polar heads. The distribution of the two molecules along the interface is not therefore uniform. This induces an inhomogeneity ...

Adsorption of Sodium Alkyl sulfates on Nylon Particles

The adsorption of sodium alkyl sulfates (sodium decyl, sodium dodecyl, sodium tetradecyl and sodium hexadecyl sulfates) on nylon particles from their aqueous solutions was investigated by the electrokinetic method. The equilibrium adsorption isotherms of the surfactants were obtained from the electrokinetic potentials of particles dispersed in aqueous solutions of sodium alkylsulfates at different temperatures. The equilibrium constant of adsorption, K, and the saturated adsorption amount, Γs, were determined from Langmuir plots. The values of K and Γs by the electrokinetic method were compared with those obtained by the electric conductivity method under the same experimental conditions, The values of K and thermodynamic parameters determined by the electrokinetic and electric conductivity methods agreed with each other. The values of Γs obtained by the former method, however, were from 1/40 to 1/50 those calculated by the latter. Comparison of Γs by the both methods provided information on the slipping plane and the dissociation degree of the adsorbed surfactants.

Conformational transition of poly(N‐vinylpyrrolidone) in aqueous solution of sodium decyl sulphate

AbstractThe intrinsic viscosity of four poly(N‐vinylpyrrolidone) fractions in the molecular weight range from 2.75 × 104 to 3.5 × 105 was measured in a cosolvent mixture of water/sodium decyl sulphate with different sodium decyl sulphate concentrations below its critical micellar concentration. Measurements were made in the temperature range 25−40°C.The value of the a and K parameters of the Mark‐Houwink‐Sakurada equation were determined. The values obtained for a were in general high, as expected for good solvents. Using the Stockmayer‐Fixman equation with the data, Kθ and B, i.e. the short and long range interaction parameters respectively, were calculated, which showed the existence of a conformational change at 12.3 mM sodium decyl sulphate concentration, at all temperatures.The polymer‐solvent interaction parameter X for the fraction of molar mass 3.5 × 105 was also determined.

ChemInform Abstract: Influence of Disc‐Rod‐Sphere Phase Transitions in Nematic Lyotropics on a Unimolecular Isomerization Reaction.

AbstractThe unimolecular isomerization of the photochromic merocyanine (II) to the indolinospiropyran (I) is performed in the nematic lyophases formed by potassium laurate or sodium decyl sulfate with 1‐decanol and water.

Electrochemistry of methylviologen in the presence of sodium decyl sulfate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemistry of methylviologen in the presence of sodium decyl sulfatePablo A. Quintela and Angel E. KaiferCite this: Langmuir 1987, 3, 5, 769–773Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published inissue 1 September 1987https://doi.org/10.1021/la00077a034RIGHTS & PERMISSIONSArticle Views300Altmetric-Citations34LEARN 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 (645 KB) Get e-Alerts Get e-Alerts

Solubility of tris(acetylacetonato)cobalt(III) in micelles. Comparative study of sodium alkylsulfates and alkyltrimethylammonium bromides

The solubility of tris(acetylacetonato)cobalt(III) [Co(acac)3] has been measured in aqueous surfactant solutions of sodium decylsulfate (NaDeS), dodecylsulfate (NaDS), and tetradecylsulfate (NaTS), and dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB), and hexadecyltrimethylammonium bromide (CTAB) at 35°C. The solubility increases in the order DTAB∼TTAB∼CTAB<NaDeS<NaDS<NaTS. The solubility is also measured in alkanols and n-decane. Addition of sodium bromide to aqueous NaDS solution decreases the solubility of Co(acac)3. The importance of the surface solubilization is suggested. The results are compared with those for other solubilizates.

Cryptand 222 complexation of anionic surfactant counterions: drastic decrease of the cmc of sodium dodecyl and sodium decyl sulfates

Addition de Cryptand 222 a une solution micellaire de laurylsulfate de sodium et de decylsulfate de sodium. Etude de la variation de la concentration critique micellaire

Secondary structures of bovine serum albumin in anionic and cationic surfactant solutions

Secondary structure changes of bovine serum albumin were examined in solutions of sodium decyl sulfate (SDeS), sodium dodecyl sulfate (SDS), decyltrimethylammonium bromide (DeTAB), dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB), and hexadecyltrimethylammonium bromide (HTAB). The relative proportions of α-helix, β-structure, and random coil were estimated by simulating a mixed circular dichroism (CD) spectrum of reference spectra of the corresponding structures to the experimentally obtained spectrum of the protein. The helical proportion of the protein was 66% at neutral pH. This helical proportion of the protein decreased to 52% in SDeS, to 50% in SDS, to 51% in DeTAB, to 49% in DTAB, and to 47% in TTAB and HTAB. All of these surfactants caused changes in the helical proportion from 66 to approximately 50%. However, the shorter the hydrocarbon chain a surfactant had, the higher the concentration necessary to cause the same decrease in the helical proportion. The results also indicate that the longer the hydrocarbon chain of the surfactant the greater the decrease in the helical proportion. In this study the proportion of β-structure increased slightly in every surfactant solution except DeTAB. The well-known complexes AD n (A = BSA, D = SDS, n = 40–55) and AD 2 n are formed when the helical proportion of BSA decreases to 62 and 54%, respectively. The authors speculated, on the basis of Brown's model, which segments of the helix in BSA unfold in surfactant solutions.

Bimolecular Reactions in Nematic Lyotropics: A Study of Catalyzed Ester Hydrolysis in N C, NL, and I Phases

Abstract Myristyltrimethylammonium bromide forms both a nematic cylindrical and lamellar lyophase depending on the concentrations of water, ammonium bromide and 1-decanol. The rate of o-iodosobenzoic acid catalyzed hydrolysis of p-nitrophenyl laurate is significantly higher in the cylindrical phase, indicating that the size and shape of an aggregate can influence reactivity of dissolved species. Similar effects have been reported by us earlier for the bromination of trans-stilbene (a bimolecular reaction) in sodium decyl sulfate surfactant lyophase.

Photoprocesses in sodium decyl sulphate micellar media

The absorption and fluorescence behaviour of thionine dye in sodium decyl sulphate (sds) medium has been studied in detail. The transient spectra and kinetics of decay of semithionine species produced by photoreduction of thionine by ferrous ions has-been studied using flash photolysis technique. The results have been compared with those in neat aqueous medium and in sodium lauryl sulphate (sls) media published earlier. It was found that the decay of semithionine which is kinetically second order in neat aqueous medium becomes pseudo first order as in thesls medium; however unlike in the latter case, the pseudo first order rate decreases with increasing surfactant concentration at all concentrations of ferric ion. The effect of electrolyte concentration on transient semithionine spectra and decay kinetics has also been studied. It was found that with increasing NaCl concentration the transient absorbance decreases and the decay slowly reverts back to second order as in aqueous medium. Insds medium as compared tosls a much higher concentration of NaCl is needed for the reaction to become second order which is attributed to stronger binding of ferric ions to thesds micelles.

Effects of pressure on the photodimerization of acenaphthylene in micellar systems

The photodimerization of acenaphthylene in aqueous micellar systems of a series of sodium n-alkyl sulphates (sodium octyl sulphate, decyl sulphate and dodecyl sulphate) and hexadecyltrimethylammonium bromide has been studied at high pressures up to 150 MPa. The dimerization was strongly influenced by the size and shape of the micelles used and by the pressure, but not by the charge on the surfactants. Pressure promoted dimerization in all micellar systems studied. The dimerizations of acenaphthylene in these heterogeneous systems have been compared with those in homogeneous organic solvents (n-alkanes, methanol and carbon tetrachloride) at atmospheric and high pressures. In homogeneous systems the dimerization is retarded or unaffected by pressure.

Surface tension of aqueous solutions of prostaglandins and related unsaturated fatty acids.

The surface properties of prostaglandins F2a, E2, D2, A2 and B2 at the air-water interface were studied under conditions where these compounds are stable. Our values of critical micelle concentrations (cmc) of prostaglandins F2a, E2, A2 and B2 at pH 7.80 were 2.7×10-2, 1.3×10-2, 8.8×10-3 and 6.2 ×10-3 mol·dm-3, respectively, whereas the formation of micelles at pH 4.96 was not detected for any of the prostaglandins tested. The cmc for prostaglandin D2 could not be determined due to the instability of the compound at pH 7.80. However, the surface behavior of prostaglandin D2 at pH 4.96 was very similar to that of prostaglandin E2, indicating that prostaglandin D2 may have a value of cmc at pH 7.80 close to that of prostaglandin E2. These values of prostaglandins are comparable to those of sodium decyl sulfate, dodecanoic acid and tetradecyl phosphate. Possible structures of prostaglandins at the air-water interface and probable mechanisms of membrane penetration and permeation are discussed.

The mechanism of clouding in triton X-100: The effect of additives

The mechanism of clouding in the nonionic surfactant is investigated through the effect of additives. The cloud point of Triton X-100 is shown to be very sensitive to the additions of small amounts (10 −5 M) of charged surface active agents while the cloud point remains unaltered on addition of same amount of the salt NaCl and n-butanol (10 −5 M). This is considered to be a clear indication of the result of charging the micellar surface. The linear rise in the clouding temperature of a Triton X-100 with the addition of additives sodium lauryl sulfate, sodium decyl sulfate, and sodium dodecyl benzene sulfonate up to a maximum concentration of 1 molecule per micelle of Triton X-100, is interpreted in terms of the rise in surface charge of the micelle. It is concluded that these observations support the view of regarding the cloud point as a critical phenomenon rather than the growth of micelles.

Fluorescence probes for critical micelle concentration determination

The utility of pyrene and pyrene-3-carboxaldehyde as fluorescence probes for determining the critical micelle concentration (cmc) of nonionic (Tergitol25-L-9, Tergitol15-5-40, Neodol91-8), anionic (sodium decyl sulfate), and cationic (cetyltrimethylammonium bromide) surfactanb was investigated. The probes were dissolved in trace amounts (<lo4 kmol/m3) in a series of aqueous solutions of these surfactants. Results obtained indicated that the surfactant concentration at which a marked decrease in the A,, parameter of pyrene-3-carboxaldehyde occurs corresponds to the cmc determined by surface tension. In contrast, the customarily used parameter, 11/13, of pyrene undergoes a reduction at concentrations close to, but consistently lower than, the accepted cmc values of the surfactant. Thus, it appears that pyrene-3carboxaldehyde is the more reliable probe for cmc determination. Surface tension results show, furthermore, that the probe molecules at the levels used to determine the cmc by fluorescence do not noticeably affect the surfactant properties, viz., surface tension, nor the surface tension derived cmc value.

ChemInform Abstract: SOLVENT ISOTOPE EFFECT ON THE REACTIVITY OF PHOTOPRODUCED CATIONS EMBEDDED IN MICELLES

Lifetime distributions of photoproduced N,N,N',N'-tetramethylbenzidine cation radicals in micelles of sodium decyl sulfate and of sodium dodecyl sulfate in H/sub 2/O and D/sub 2/O were determined from inverse Laplace transforms of the experimental decay at room temperature. An expression is given for adequately approximating the decay curves. Hydrophobic interaction due to substitution of D/sub 2/O for H/sub 2/O results in broadening of the lifetime distribution accompanied by an increase in the effective lifetime. The lifetime broadening effect was found to be similar in both kinds of micelles.

Demixing of Nematic Lyophases

Abstract We are studying the conditions for the demixing of nematic lyomesophases from decanol, heavy water and sodium decylsulphate or potassium laurate.

The surface adsorption and micelle formation of the mixed aqueous solutions of fluorocarbon and hydrocarbon surfactants: II. Sodium perfluorooctanoate-sodium decylsulfate system

The adsorption and micellar behavior of the mixed solutions of sodium perfluo- rooctanoate (7CFNa) and sodium decylsulfate (C_(10)SNa) have been studied (the ionic strength of the solutions are kept at 0.1m by adding NaCl). The adsorption has been calculated from the surface (and interfacial) tension-concentration curves by applying Gibbs equation Γ_T=-(1/RT)dγ/d lnm_(7CF)=-(1/RT)dγ/d lnm_(C_(10)S~-) where Γ_T(=Γ_(7CF-)+Γ_(C_(10)S~-)) is the total amount of adsorption. It has been found that the cmc's of 7CFNa and C_(10)SNa are of nearly the same value (1.66×10~(-2)m and 1. 45 ×10~(-2)m, respectively), but γ_(cme) of 7CFNa solution is～23mNm~(-1) which is much lower than that of C_(10)SNa solution. This implies that 7CFNa would have a much higher surface activity than C_(10)SNa, and 7CFNa would be adsorbed preferentially. For instance, 7CFNa has a surface mole fraction of about 0.8 in the saturated adsorption layer of the 1: 1 molal mixed solution. The mole fractions of 7CFNa at the surface are always greater than those in the bulk solutions. The adsorption at the n-heptane-aqueons solution interface is quite different from that at the air-solution surface. Here C_(10)SNa is preferentially adsorbed owing to mutual phobicity between the HC-chain of n-heptane and the FC-chain of 7CFNa at the interface. All the cmc of 7CFNa(or C_(10)SNa) in the mixed solutions obtained from the γ-logm relations have nearly the same value and the cmc_T-x curves show a positive deviation from the ideal case. This further indicates that in the mixed solutions of fluorocarbon and hydrocarbon surfactants there is no completly miscible micelle but essentially the individual micelle of each surfactant due to the mutual phobicity between FC- and HC-chain in the micellization process.

Solvent isotope effect on the reactivity of photoproduced cations embedded in micelles

Lifetime distributions of photoproduced N,N,N',N'-tetramethylbenzidine cation radicals in micelles of sodium decyl sulfate and of sodium dodecyl sulfate in H/sub 2/O and D/sub 2/O were determined from inverse Laplace transforms of the experimental decay at room temperature. An expression is given for adequately approximating the decay curves. Hydrophobic interaction due to substitution of D/sub 2/O for H/sub 2/O results in broadening of the lifetime distribution accompanied by an increase in the effective lifetime. The lifetime broadening effect was found to be similar in both kinds of micelles.

Influence of small quantities of isomeric alcohols on the surface tension behavior of aqueous sodium alkyl sulfate solutions

The influence of the addition of small quantities of isomeric alcohols (⩽ 0.5 mol %) of different alkyl chain length (C 8 – C 13) on the surface tension of sodium decyl sulfate (SDS) and sodium dodecyl sulfate (SDDS) solutions in the concentration region ⩽ CMC (critical micelle concentration) was systematically investigated. The surface tension of pure sodium alkyl sulfate (SAS) solutions ( c ⩽ CMC) progressively decreases with increasing chain length of the straight-chain alcohol added. Isomeric alcohols with the same total C number on the surface tension of SAS depends on the branching ratio of the alcohol. The results are explained by the change in the ratio of the bulk—surface distribution coefficients α SAS/α ROH. The characteristic adsorption parameters were therefore calculated for selected systems using the universal Frumkin surface equation of state ( H s ≠ 0) and a Langmuir-type equation ( H s = 0). On the basis of the generalized Szyszkowski equation a method for calculating the bulk—surface distribution coefficient of slightly soluble isomeric alcohol is proposed.