Solutions Of Sodium Alkyl Sulfates Research Articles

Relationship between air-water interfacial dilational viscoelasticity and foam property in aqueous solutions of sodium alkylsulfates with different hydrocarbon chains

The influence of alkyl chain structures in sodium alkylsulfates (ASs) on their rheological properties was investigated in this study. Dilational viscoelasticity at the air-water interface, dynamic surface tension, and foam property were quantitatively evaluated in aqueous solutions of ASs with different hydrocarbon chains, and the relationship was systematically discussed. The experimental results show that the alkyl chain plays an important role in the interfacial dilational properties. For ASs with straight alkyl chains, AS with the longer alkyl chain showed the maximum value of the interfacial dilational viscoelasticity at the lower concentration. The longer the alkyl chain of AS was the larger the maximum value of the interfacial dilational viscoelasticity was. The frequency dependence of the interfacial dilational viscoelasticity was confirmed only in the range of high surfactant concentrations, suggesting that the interfacial relaxation process is mainly controlled by the diffusion of the surfactants. As for the relationship between interfacial dilational viscoelasticity and foam property, it was found that the maximum value of the interfacial dilational viscoelasticity was correlated with the foam stability under the conditions.

Potentiometric sensors based on new active components in the multisensor determination of homologues anionic surfactants

Potentiometric sensors are proposed on the basis of alkyl sulfates and cationic copper(II) complexes with organic reagents selective to anionic surfactants. Physical and chemical properties of the ionophores (composition, thermal stability, solubility) are determined in aqueous solutions and in the membrane phase. The studied compounds are poorly soluble (K s = n × 10–22–n × 10–20) and thermally stable at 80−90°C. The main electroanalytical properties of sensors are estimated, i.e., analytical range in solutions of sodium alkyl sulfates 2 × 10–7–1 × 10–2 M; 46 <α < 66 mV/рc; LOD = 1 × 10–7 M; response time 8–9 s in a solution of sodium dodecyl sulfate with the concentration not lower than 1 × 10–4 M; potential drift 2–3 mV/day; and lifetime 12 months. The multisensor determination of homologues sodium alkyl sulfates in model mixtures and natural waters is performed using the proposed sensors.

Calorimetric Study of Micelle Formation of Sodium Alkyl Sulfates in Water

Calorimetric measurements were conducted on aqueous solutions of sodium alkyl sulfates (SCnS; H(CH₂)nOSO₃Na, n = 5-13) at 298.15 K. The solute partial molar enthalpy, H(s), was evaluated referred to infinitely diluted state and compared for the SCnS homologues. At low concentrations, the H(s) increased with the molality m until the critical micelle concentration (CMC) was reached. In the concentration range between the CMC and about three times the CMC, the Hs decreased with increasing log m: H(s) = (17.9 - 1.8 n) - 14/(n-4.6) log m. The Hs observed at the CMC was taken as the enthalpy of micelle formation, ΔH(m), which was expressed as ΔH(m) / kJ mol(-1) = 21.3 - 1.7 n for SCnS with n from 7 to 13. The Gibbs energy of micelle formation, ΔG(m), was estimated from the CMC values: ΔG(m) / kJ mol(-1) = 0.2 - 3.1 n. The entropy of micelle formation, ΔS(m), was calculated as TΔS(m) / kJ mol(-1) = 21.1 + 1.4 n. The large positive entropy term was the driving force for micelle formation. An attempt was also made to calculate the concentration dependence of Hs for SDS (SC₁₂S) from the concentrations and the apparent molar enthalpies estimated for the sodium ion, dodecyl sulfate ion, and the micelles.

Thermodynamic analysis of the dynamic structure of micellar solutions of sodium alkyl sulfates

The results of previous studies of the increments \( \Delta G_{CH_2 }^0 \), \( \Delta H_{CH_2 }^0 \), and \( T\Delta S_{CH_2 }^0 \) in hydrocarbon solution processes in water, evaporation, hydration, and transfer from vapor and water to surfactant micelles are summarized. The corresponding thermodynamic cycles were constructed. A micelle was shown to be a bistable structure formed by the contact and water-separated hydrophobic interactions of the alkyl groups of surfactants. The fraction in \( \Delta G_{CH_2 (M)}^0 \) is −2.3 kJ·mol−1 for the contact associate and −0.7 kJ·mol−1 for the hydrated one. Water is involved in the hydrophobic interaction of each associate. In a dualist micelle, however, \( \Delta G_{CH_2 }^0 \) = −3.0 kJ mol−1 equals that of the dispersion interaction after condensation from vapor. The dual nature of the dynamic properties of micelles is discussed.

Surface Tensions of Aqueous Solutions of Sodium Alkyl Sulfates in Contact with Methane under Hydrate-Forming Conditions

This paper presents experimental data on the surface tensions of aqueous solutions of sodium alkyl sulfates (ionic surfactants) in contact with methane at a pressure of 3.90 MPa and a temperature of 275 K (i.e., a condition in which a clathrate hydrate of methane is thermodynamically stable). These data were obtained in the metastable absence of any hydrate in the experimental system (i.e., every measurement was accomplished during the induction time for hydrate formation). Three sodium alkyl sulfates appreciably different in length of the hydrophobic radicals were usedthey were sodium dodecyl sulfate (SDS), sodium tetradecyl sulfate (STS), and sodium hexadecyl sulfate (SHS). The concentration of each of these surfactants was varied over a range including the critical concentration above which the surface tension levels off. On the basis of visual observations of pendant drops of SDS solutions, we identified the critical concentration for SDS as the solubility above which a hydrated solid of SDS forms instead of the critical micelle concentration (CMC) above which micelles of SDS would form. The SDS solubility was thus determined to be (2.2 to 2.3) g·kg-1, which agrees, within mutual uncertainties, with the CMC determined at a higher temperature, 293 K, either in the same pressurized methane ambience or in the air under atmospheric pressure. These results completely conflict with those reported by Sun et al. in their recent paper published in this Journal (J. Chem. Eng. Data 2004, 49, 1023−1025).

Nanoscale Supramolecular Ordering in Gel−Surfactant Complexes: Sodium Alkyl Sulfates in Poly(diallyldimethylammonium Chloride)

Studies of slightly cross-linked polycationic gels interacting with anionic surfactants have been performed by using random copolymers of poly(diallyldimethylammonium chloride) (PDADMACl) and polyacrylamide (PAAm) with varying content of PDADMACl and degree of cross-linking. Gel samples which had been fully swollen in water were placed in aqueous solutions of sodium alkyl sulfates (octyl (SOS), decyl- (SDCS), dodecyl (SDS), tetradecyl (STS), and hexyl (SHS) sulfates). The degree of the sample volume contraction depends on the PDADMACl content. The collapsed gel−surfactant complexes were studied using synchrotron small-angle X-ray scattering. All studied samples containing PDADMACl exhibited pronounced supramolecular nanostructures. The gel−SDCS complex exhibited a cubic structure with a periodicity (7.75 nm) of approximately 4 times the surfactant molecular length, while the gel−SDS, gel−STS, and gel−SHS complexes showed hexagonal supramolecular ordering with a periodicity of approximately 2 times the surfactant molecular length. The d spacing of the longest periodicity in the complexes was dependent on the PDADMACl content and the surfactant. The d spacing generally increased with decreasing PDADMACl (charge) content and increasing number of carbon atoms in the surfactant alkyl chain.

Structural effect on the adsorption properties of aqueous solutions of straight-chain and cyclic dodecyl sulfates

The adsorption properties of aqueous solutions of sodium alkyl sulfates and their oxyethylates have been studied systematically. The effect of defined structural changes on the adsorption parameter values calculated on the basis of Frumkin's surface equation of state has been demonstrated. In particular, a comparison has been made between n-dodecyl and cyclododecyl as hydrophobic groups in sodium alkyl sulfate and its ethers. The limiting areas obtained by surface tension measurements have been discussed on the basis of the crystal structure data of n-dodecyl sulfate and theoretical calculations on the three-dimensional shape of selected conformers of cyclododecyl sulfate.

Partial Molar Volumes of Sodium Alkyl Sulfates and Disodium α,ω-Alkanediyl Disulfates in Aqueous Solutions

Abstract The densities of aqueous solutions of sodium alkyl sulfates, H(CH2)nSO4Na (n = 1—6, 8, 10, 12) and disodium α,ω-alkanediyl disulfates, NaO4S(CH2)nSO4Na (n = 2—4, 6, 8, 10) were measured at 25 °C, and the limiting partial molar volumes were calculated. The group partial molar volume of SO4− was estimated to be 44.0 cm3 mol−1.

Secondary structural changes of metmyoglobin and apomyoglobin in anionic and cationic surfactant solutions: effect of the hydrophobic chain length of the surfactants on the structural changes.

Secondary structural changes of metmyoglobin and apomyoglobin were examined in solutions of sodium alkylsulfates with hydrocarbon numbers of 8 and 12, and alkyltrimethylammonium bromides with hydrocarbon numbers of 10, 12, 14, and 16. The relative proportion of alpha-helical structure was estimated by the curve-fitting method of circular dichroic spectrum. The helical proportions of metmyoglobin and apomyoglobin were 82 and 63%, respectively. The shorter the hydrocarbon chain the surfactant had, the higher the concentration necessary to disrupt the secondary structures of these proteins. However, the helical proportion had a tendency to decrease down to lower values in solutions of the cationic surfactants with short hydrophobic groups. On the other hand, the alpha-helical structure of apomyoglobin was disrupted in lower concentrations of each cationic surfactant than that of metmyoglobin, although the disruptions of the same structures in both the proteins occurred in the same concentration range of each anionic surfactant. It appeared likely that the removal of the heme group unstabilized the myoglobin conformation only in the cationic surfactant solutions.

Magnetic field, additive and structural effects on the decay kinetics of micellized triplet radical pairs. Role of diffusion, spin-orbit coupling and paramagnetic relaxation

The geminate recombination kinetics of the radical pairs produced by quenching of the triplet aromatic ketones or quinones by 4-phenylphenol and 4-phenylaniline in aqueous micellar solutions of sodium alkyl sulfates in the presence of additives (ethanol, NaCl, bromo- and iodobenzenes, paramagnetic species) has been examined using the laser flash technique. The recombination rates increase as the micellar size in decreased. Application of an external magnetic field (0.45 T) results in the retardation of geminate recombination up to 25 times. The magnetic field effect is quenched by internal or even external heavy atoms as well as by paramagnetic species, including 3O 2. The magnetic field dependences and attendant regularities are considered in terms of a simple kinetic scheme, in which the singlet-triplet evolution in the separated states of a pair due to hyperfine coupling and relaxation mechanisms, as well as intersystem recombination due to the spin-orbit coupling in the contact states of a pair, are included as first-order processes. The corresponding kinetic parameters of the different pathways involved are also discussed.

Effect of isomeric alcohols as a minor component on the adsorption properties of aqueous sodium alkyl sulfate solutions

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of isomeric alcohols as a minor component on the adsorption properties of aqueous sodium alkyl sulfate solutionsD. Vollhardt and G. CzichockiCite this: Langmuir 1990, 6, 2, 317–322Publication Date (Print):February 1, 1990Publication History Published online1 May 2002Published inissue 1 February 1990https://doi.org/10.1021/la00092a005RIGHTS & PERMISSIONSArticle Views106Altmetric-Citations30LEARN 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 (657 KB) Get e-Alerts Get e-Alerts

Effect of solubilization of CO 2 on the critical micelle concentration of sodium alkyl sulfonates

The critical micelle concentrations (CMC) of aqueous solutions of octyl, decyl, and dodecyl sodium sulfonate have been measured as a function of CO 2 pressure. A thermodynamic model which describes the observed decline in CMC and determines the mole fraction of CO 2 in the micelle is presented. This model is then tested against reported solubility data of other gases in sodium alkyl sulfate solutions and found to be in good agreement. On the basis of these results it appears that the concept of a micelle Laplace pressure is not necessary to explain solubilization in micelles.

Distribution coefficients of nonpolar additives and factors determining the solubilization tendency as a function of surfactant chain length in aqueous solutions of sodium alkyl sulfates

Determination des tendances a la solubilisation du benzene, cyclohexane et n-hexane dans des solutions aqueuses d'hexyl-, octyl-, lauryl-, myristyl- et palmitylsulfate de sodium, a 43,8°C

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.

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 (C8 – C13) 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 αSAS/αROH. The characteristic adsorption parameters were therefore calculated for selected systems using the universal Frumkin surface equation of state (Hs ≠ 0) and a Langmuir-type equation (Hs = 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.

Kinetic Study on Conformational Changes of Poly(l-lysine) in Sodium Alkyl Sulfate Solutions. Effects of Surfactant Chain Length and Added NaCl

Abstract The conformational changes of poly(l-lysine) (PLL) were observed in alkyl sulfate solutions by a circular dichroic method. PLL forms a β-structure in sodium dodecyl sulfate solution with an apparent first-order rate constant of 3.0×10−2 s−1 (20 °C). In sodium octyl sulfate (SOS) solution, PLL assumes the α-helix within a certain concentration range of the surfactant, above which the β-structure is favored. The rate of coil to β-structure transition slows down with increase in hydrophobic interaction between surfactants and PLL. The presence of sodium ions decreases the rate of coil to α-helix transition by about two orders of magnitude (2.0×10−1 s−1 salt free to 3.0×10−3 s−1 in the presence of 2.0×10−2 mol/dm3 NaCl at 20 °C). These phenomena are explained in terms of a rearrangement process of bound surfactants adjusting for a free energy minimum; a stronger binding force brings about a slower rearrangement rate.

Chemical relaxation studies in micellar solutions of sodium alkyl sulfates

Pressure-jump-induced chemical relaxation measurements were carried out with solutions of sodium decyl sulfate (SDeS), sodium dodecyl sulfate (SDS), and sodium tetradecyl sulfate (STS). In pure SDeS solution no relaxation effect could be observed in the time range of the pressure-jump technique, whereas by adding a small amount of decyl alcohol, typical relaxations were observed which gave τ −1 increasing linearly with SDeS concentration. In pure SDS solution only one relaxation was observed which yielded τ −1 almost independent of SDS concentration. In pure STS solution, two well-separated relaxation processes were observed. The slow relaxation time ( τ 2) was almost independent of the concentration, while the reciprocal of the fast relaxation time ( τ 1 −1) increased linearly with the concentration. τ in pure SDS and in SDeS with added decyl alcohol and τ 2 in pure STS were interpreted as those associated with the micelle-forming process, while τ 1 in pure STS was interpreted as that associated with the so-called exchange process. The effects of added long chain alcohol on τ were also studied for SDS and STS. A discussion of the present results on STS was attempted according to several models which were proposed previously.

Effect of chain length and concentration of anionic surfactants on the conformational transitions of poly(L-ornithine) and poly(L-lysine) in aqueous solution

The conformation of poly(L-ornithine) (PLO) and poly(L-lysine) (PLL) in solutions of sodium alkyl sulfates, CH 3(CH 2) nSO 4Na with n = 7, 9, 11, 13 and 15 was studied by circular dichroism. PLO adopts a helical conformation in all 5 homologs and PLL a β-form in only 4 of the homologs. With octyl sulfate PLL has a helical conformation instead. These conformations were observed in solution of surfactants both below and above the critical micelle concentration.

The Saturated Adsorption of Sodium Alkyl Sulfates at the Air-Solution Interface

Equilibrium surface tensions of the aqueous solutions of sodium alkyl sulfates containing 8, 10, 12, 14 carbon atoms were elaborately measured at the air-solution interface by means of the Wilhelmy plate method at 300C, and the amounts of adsorption were calculated by using the Gibbs adsorption isotherm. lsotherm for adsorption shows the saturation at a concentration below the critical micelle concentration (CMC) of respetive solution. The concentration at which the adsorption was Saturated was defined as the saturated adsorption concentration (SAC). The logarithm of SAC held a good linearity against th6 number of carbon atoms (N)in the surfactants. lt was shown in the theoretical and experimental approaches that the molecular cross-seetional area in the region of saturated adsorption increases linearly with increase in N. The energy difference between the micelle formation in the solution and the adsorption at the air-solution interface was calculated as 47. l cal/mol per methy1ene group from the theoretical analyses. This value was in good agreement with one calculated from the theory of mic elle formation given by Shinoda and from the energy data of desorption for methylene group at the air-solution and oil solution interfaces. ln the Similarity to the characteristics of the CMC in the surfactant solution, the SAC may likely be used as a good measure to interpret the surface phenomena at the air-solution interface.

Catalysis of ionic reactions by micelles. Reaction of chloropenteamminecobalt ion with mercury (II) ion in sodium alkyl sulfate solutions

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCatalysis of ionic reactions by micelles. Reaction of chloropenteamminecobalt ion with mercury (II) ion in sodium alkyl sulfate solutionsJune-Ru Cho and Herbert MorawetzCite this: J. Am. Chem. Soc. 1972, 94, 2, 375–377Publication Date (Print):January 1, 1972Publication History Published online1 May 2002Published inissue 1 January 1972https://doi.org/10.1021/ja00757a011RIGHTS & PERMISSIONSArticle Views84Altmetric-Citations38LEARN 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 (343 KB) Get e-Alerts Get e-Alerts