Sodium Alkyl Research Articles

The influence of mixed cationic–anionic surfactants on the three-phase contact parameters in silica–solution systems

The formation of thin wetting films on silica surface from aqueous solution of (a) tetradecyltrimetilammonium bromide (C 14TAB) and (b) surfactant mixture of the cationic C 14TAB with the anionic sodium alkyl- (straight chain C 12–, C 14– and C 16–) sulfonates, was studied using the microscopic thin wetting film method developed by Platikanov. Film lifetimes, three-phase contact (TPC) expansion rates, receding contact angles and surface tension were measured. It was found that the mixed surfactants caused lower contact angles, lower rates of the thin aqueous film rupture and longer film lifetimes, as compared to the pure C 14TAB. This behavior was explained by the strong initial adsorption of interfacial complexes from the mixed surfactant system at the air/solution interface, followed by adsorption at the silica interface. The formation of the interfacial complexes at the air/solution interface was proved by means of the surface tension data. It was also shown, that the chain length compatibility between the anionic and cationic surfactants controls the strength of the interfacial complex and causes synergistic lowering in the surface tension. The film rupture mechanism was explained by the heterocoagulation mechanism between the positively charged air/solution interface and the solution/silica interface, which remained negatively charged.

Phase Behaviour of the Microemulsion Systems Formed by the Composite Surfactants Alkyl Polyglucoside and Sodium Dodecyl Sulfate

Abstract The phase behavior of microemulsions containing composite surfactants of non-ionic alkyl polyglucoside and anionic sodium dodecyl sulfate was studied by the ∊-β fishlike phase diagram method. In microemulsion systems APG(SDS)/alcohol/alkane/water, there exists an obvious synergistic effect in terms of the composition of the interfacial layer and the solubilization ability. In the interfacial layer the number of surfactant and alcohol molecules notably decrease, resulting in a significant improvement in the solubilization ability of the system. The effects of alcohols, alkanes and salinity on the ∊-β fishlike phase diagrams of APG/SDS/alcohol/alkane/brine microemulsion systems were also discussed.

An unexpected Hoffmann elimination during the alkylation of dihydrotetrabenazine

Dihydrotetrabenazine (DTBZ) is the major pharmacologically active form of tetrabenazine (TBZ), which was approved by FDA for the treatment of chorea associated with Huntington's disease (HD). An unexpected Hoffmann elimination was observed during the treatment of DTBZ with sodium hydrogen and alkyl halides, leading to the formation of both eliminated products (major) and hydroxyl-alkylated products (minor).

Multifunctional Separation Mechanism on Poly(oxyethylene) Stationary Phases in Capillary Liquid Chromatography

The retention behavior on poly(oxyethylene) (POE) chemically-bonded stationary phases was investigated in ion-exchange, reversed-phase (RP) and hydrophilic interaction (HILIC) modes in capillary liquid chromatography. The eluent cations fixed on the oxygen atoms of the POE chains by ion-dipole interaction worked as the anion-exchange sites for the separation of inorganic anions. Nonpolar analytes were retained on the POE stationary phases in the RP mode, while polar organic analytes were retained in the HILIC mode. Sodium alkyl sulfate dynamically modified on the stationary phase enhanced the hydrophobic property of the stationary phase. The effect of the oxyethylene unit number on the retention behavior was examined, and it was expected that the eluent cation is trapped among multiple POE chains by ion-dipole interaction.

ChemInform Abstract: Alkylation of Sodium 2,6-Di-tert-butylphenolate with Perfluoropropyl and -methyl Iodides.

ChemInform Abstract: Alkylation of Sodium 2,6-Di-tert-butylphenolate with Perfluoropropyl and -methyl Iodides.

Surfactant-Mediated Ion Exchange and Charge Reversal at Ionic Liquid Interfaces

Room-temperature ionic liquids (ILs) exhibit a unique set of properties due to their charged character, presenting opportunities for numerous applications. Here, we show that the combination of charged surfactants with ILs leads to rich interfacial behavior due to the interplay between electrostatic and surface forces. Using traditional measures of surface activity and X-ray photoelectron spectroscopy (XPS), we find that sodium alkyl sulfates and alkyl trimethylammonium bromides are, indeed, surface-active at the air-IL interfaces of both [EMIM][EtSO(4)] and [BHEDMA][MeSO(3)]. XPS also reveals that surfactant counterions readily dissociate into the bulk, which when combined with the surfactant surface activity has striking consequences. We find that ion exchange occurs between surfactants and like-charged IL ions, with the greatest exchange for short surfactant alkyl chains. The initial negative surface charge of neat [EMIM][EtSO(4)] can be switched to positive by the addition of alkyl trimethylammonium bromides, with the effect most pronounced at short chain lengths. By contrast, the surface charge of [BHEDMA][MeSO(3)] is largely unaffected by the added surfactants, suggesting a key role for the strength of ion-pairing within the IL. The results here illustrate a simple but effective means of manipulating IL interfacial properties.

ChemInform Abstract: Indium-Mediated Reaction in Aqueous Media. Synthesis of Phenacyl Sulfides by Reactions of α-Bromoketones with Sodium Alkyl Thiosulfates.

Phenacyl sulfides are synthesized in moderate to good yields via reaction of α-haloketones with sodium alkyl thiosulfates promoted by indium metal in aqueous media.

ChemInform Abstract: Metallic Samarium Promoted Reductive Dimerization Cyclization of gem-Diactivated Alkenes, Reductive Debromination of vic-Dibromides, and Reduction of Sodium Alkyl Thiosulfates in Aqueous Media.

Abstract In saturated NH 4 Cl (ap.)-THF solution at room temperature, metallic samarium promoted reductive dimerization cyclization of gem -diactivated alkenes, reductive debromination of vic -dibromides, and reduction of sodium alkyl thiosulfates occur to afford corresponding functionalized cyclopentenes, ( E )-alkenes, and disulfides, respectively in good yield. Only sub-stoichiometric quantities of samarium are employed in the former reactions and the trans - or trans,trans -form isomer is the majority product of the polysubstituted cyclopentene products.

Structure, Interfacial Properties, and Dynamics of the Sodium Alkyl Sulfate Type Surfactant Monolayer at the Water/Trichloroethylene Interface: A Molecular Dynamics Simulation Study

In this work, we perform a series of molecular dynamics (MD) simulations on the category of sodium alkyl sulfate (SDS-type) surfactant monolayers at the water/trichloroethylene (TCE) interface. Three separate tail-length SDS-type molecules are used. We investigate the conformation of surfactant chain (i.e., packing, orientation, and order), interfacial properties (i.e., interfacial thickness, interfacial tension, area compressibility, and bending modulus), their dependence on the chain length, and the average area per surfactant chain. We also examine the behavior of the surfactant monolayer in the metastable regime of negative surface tension with reference to collapse. The simulation has clearly shown that the very dilute monolayer is well described as a two-dimensional gas. With the increase of interfacial surfactant coverage, the monolayer is in the liquid-expanded (LE) phase. The surfactant tails at the interface become straighter, more ordered, and thicker at higher surfactant coverage. At the same time, interfacial tension of long-tail systems is always lower than that of short-tail systems. In the LE phase, the area compressibility modulus and the bending modulus increase with an increase in tail length. With a further decrease in molecular areas, the monolayer with large negative surface tension becomes unstable. Our simulations show that buckling of the monolayers is of dynamic nature as a response to mechanical instability. The further transformation pathway from buckling to bud can be controlled by the bending modulus, which depends crucially on the tail length and interfacial surfactant coverage. At a given area per molecule, the short tail chain makes the monolayer softer, and the budding process becomes more probable. For the supersaturated softer SDS monolayer, the collapse transition is initiated by the buckling of monolayers, followed primarily by budding and detachment of the nanoscale swollen micelle from the monolayer. Despite a number of extensive studies of monolayer collapse at the air/water interface, to our knowledge the conversion of surfactants from the liquid-liquid interface to swollen micellar aggregates as described here has not been reported in the literature.

Control of an Outbreak of Carbapenem-ResistantAcinetobacter baumanniiin Australia after Introduction of Environmental Cleaning with a Commercial Oxidizing Disinfectant

In the midst of an outbreak, carbapenem-resistant Acinetobacter baumannii was grown from samples of multiple environmental sites in an intensive care unit. A commercial oxidizing disinfectant (potassium peroxomonosulphate 50%, sodium alkyl benzene sulphonate 15%, and sulphamic acid 5%) was introduced throughout the intensive care unit, and its use coincided with cessation of the outbreak.

Effect of an anionic emulsifier on the structure of butadiene-nitrile elastomers

X-ray diffraction and TMA studies show that surfactant sodium alkyl sulfonate (C15) forms one of its two LC structures (distinguished by the smallest layer periodicity) in butadiene-nitrile elastomers containing different amounts of acrylonitrile units. In this case, the surfactant serves as a structural plasticizer and facilitates a more complete selective segregation of microblocks of trans-1,4-butadiene units and, especially, of sequences of alternating trans-1,4-butadiene and acrylonitrile units.

Effect of Poly (ethylene oxide) on Solubilization Behavior of Sodium Alkyl Sulfates toward Oil Yellow OB

Effect of Poly (ethylene oxide) on Solubilization Behavior of Sodium Alkyl Sulfates toward Oil Yellow OB

Relationship between Lathal Concentration and Hemolytic Activity of a Group of Anionic Surfactant, Sodium Alkyl Sulfonate, in Common Carp, Cyprinus carpio

Relationship between Lathal Concentration and Hemolytic Activity of a Group of Anionic Surfactant, Sodium Alkyl Sulfonate, in Common Carp, Cyprinus carpio

Novel Alkyl Ether Sulfonates for High Salinity Reservoir: Effect of Concentration on Transient Ultralow Interfacial Tension at the Oil–Water Interface

AbstractThe effect of surfactant concentration on the occurrence and detection of transient ultralow interfacial tension (IFT) between crude oil and formation water at 75 °C has been investigated using a series of novel sodium alkyl ether sulfonates having various increasing molecular weights and degrees of ethoxylation. All surfactant systems displayed dynamic interfacial tension (DIT). Transient ultralow DIT (DITmin) were detected only within an intermediate surfactant concentration. This behavior was attributed to an implicit concentration‐related length scale required for the added surfactant to diffuse from the bulk phase to the freshly prepared oil–water interface. In the high surfactant concentration range, this length scale is relatively short and results in an instantaneous (and undetectable) occurrence of DITmim in a relatively very short time scale, well beyond the detection limit of the spinning drop tensiometer (~2–3 min). Interestingly, DITmin were detected only in systems above the surfactant's critical micelle concentration, suggesting that DITmin occurs as a result of the diffusion (subsequent to the adsorption) of the oil acidic species from the interface to the bulk phase to form mixed micelles with the added surfactant. Measurements of DITs in the presence of decane showed no evidence for DITmin, confirming the general belief that DITmin is indeed due to the interaction of the added surfactant with the oil acidic components. Finally, the effect of surfactant concentration on the equilibrium IFT (γeq) showed evidence for relatively low values (~10−2 mNm−1) for some surfactant systems.

Mesophase formation and thermal behavior of catanionic mixtures of gemini surfactants with sodium alkylsulfates

The thermal behavior for three homologous series of cationic geminis surfactants of the type n-2-n, alkanediyl-α,ω-bis(alkyldimethylammonium bromide), with n = 12, 14, 16, and 18, and sodium alkyl sulfates, SC m S, with m = 12, 14, and 16, is reported here. The cationic/anionic molar ratio is kept at 1:2 (equicharged mixtures), and salt is also present. Polarizing light microscopy and differential scanning calorimetry show a stepwise fusion for the mixtures with appearance of several mesophases between the crystalline structures and the isotropic liquid. A main endothermic transition is observed, associated with partial chain melting and consequent loss of crystalline order, followed by a transition to a smectic liquid crystal. The phase transition thermodynamics is interpreted in terms of an interplay between van der Waals chain–chain interactions and ionic head group interactions.

Effects of Bleach Activator, Sodium Alkyl Acyloxybenzene Sulfonate, on House Dust Mites (Dermatophagoides farinae)

House dust mites (Dermatophagoides farinae) in bedding and clothes are a major allergen. However, house dust mites cannot be killed by general washing conditions under 50 degrees C. Therefore, low-temperature washing conditions must be improved to eliminate house dust mites. Sodium alkyl acyloxybenzene sulfonate (OBS) is a bleach activator that is used to intensify the bleaching effects of some laundry products. The purpose of this study was to evaluate the effect of OBS on the elimination of house dust mites in low-temperature washing conditions. D. farinae was soaked in solutions containing different types of OBS for various durations and at various temperatures. The miticidal effects of the various washing conditions were also evaluated for D. farinae. Then sodium lauroyloxybenzene sulfonate (OBS-12) produced the highest D. farinae mortality rate among the OBS solutions that were examined and had a stronger miticidal effect than available chlorine under general washing conditions. OBS exhibited miticidal effects under general washing conditions at low temperatures. Since OBS is already used as an additive in some laundry products to increase the bleaching activity, OBS can be easily used to kill house dust mites under general washing conditions.

A study on the incidence, microbiological analysis and investigations on the source of infection of postoperative infectious endophthalmitis in a tertiary care ophthalmic hospital: An 8-year study

Background:The objective of the study was the determination of the incidence of culture-proven postoperative endophthalmitis and probable sources of infection.Materials and Methods:It was a prospective study on the microbiology, incidence and probable sources of infection in patients with postoperative infectious endophthalmitis carried out in a tertiary care eye hospital. Consecutive patients diagnosed with postoperative infectious endophthalmitis during the years 2000-2007 were investigated for the causative infective agent and possible sources of infection. The surgical data and microbiological data including the investigations performed to trace the source were recorded in a specific formatted form and were gathered and compiled for analysis.Results:Data of analysis showed that 98 (0.042%) out of 2,31,259 patients who underwent intra-ocular surgery developed infectious endophthalmitis. Among these, 70 (0.053%) occurred after cataract, 10 (0.5%) after penetrating keratoplasty (PK) and 18 (0.018%) following other types of intra-ocular surgeries. The predominant infectious agents isolated were bacteria (89.7%), with equal proportions of Gram-positive and Gram-negative bacteria. Polymicrobial infection was noted in four and fungi in seven patients. Occurrence of postoperative endophthalmitis was sporadic and not related to any specific part of period in a year. Sources of infection were donor corneal rim in six post-PK patients and phaco probe in one who had postphacoemulsification endophthalmitisConclusions:Overall incidence of postoperative endophthalmitis over an 8-year period was quite low. The sources of infection could be established in six post-PK endophthalmitis patients and in a postcataract surgery.

How Chain Length and Charge Affect Surfactant Denaturation of Acyl Coenzyme A Binding Protein (ACBP)

Using intrinsic tryptophan fluorescence, equilibria and kinetics of unfolding of acyl coenzyme A binding protein (ACBP) have been investigated in sodium alkyl sulfate surfactants of different chain length (8-16 carbon atoms) and with different proportions of the nonionic surfactant dodecyl maltoside (DDM). The aim has been to determine how surfactant chain length and micellar charge affect the denaturation mechanism. ACBP denatures in two steps irrespective of surfactant chain length, but with increasing chain length, the potency of the denaturant rises more rapidly than the critical micelle concentration (cmc) declines. Increasing proportions of DDM, which significantly reduce the amount of monomeric sodium dodecyl sulfate (SDS), make the first denaturation step occur at lower concentrations but weaken and eventually remove the second denaturation step. The logarithm of the unfolding rate constants increases linearly with denaturant concentration below the cmc but declines at higher concentrations. Both shortening chain length and decreasing micellar charge reduce the overall kinetics of unfolding and makes the dependence of unfolding rate constants on surfactant concentration more complex. This behavior contrasts with the simplicity of unfolding in chemical denaturants and highlights the changing properties of surfactant micelles. We suggest that the transition from spherical to more elongated micelles leads to inhibition of unfolding kinetics, while weaker binding sites may cause a subsequent rise in unfolding rate constants at higher surfactant concentrations. We propose that shifting micellar binding sites on globular proteins such as ACBP, as opposed to the predefined binding sites on membrane protein surfaces, may lead to nonlinear correlations between activation unfolding energies and SDS mole fraction.

Phenolic foams from wood tar resols

AbstractThis article investigates resole‐type phenolic foams, in which 40% phenol was substituted with distilled oily fractions from wood tar. Different proportions of blowing agent, hexamethylenetetramine, and stabilizer, a sodium alkyl sulfate surface active agent, were used to produce a series of rigid foams, which were characterized by curing index, density and hardness. The average curing index was about 90% and densities ranged from 480 to 960 kg.m−3. A fractal dimension (Df) approach was used to assess the homogeneity of pores within the foams and an average (dimensionless) value of 2.6 was found, indicating a non uniform structure. Compressive strength tests of the foams gave values above 1.0 MPa, which is higher than those for typical phenolic foams. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Synergism in Mixed Anionic–Amphoteric Surfactant Solutions: Influence of Anionic Surfactant Chain Length

Abstract The influence of chain length on the composition of mixed micelles in binary mixtures of N,N-dimethyldodecylamine oxide (DDAO) and sodium decyl-, sodium dodecyl- and sodium tetradecylsulfate (abbreviated as SDeS, SDS and STS, respectively) has been determined at 30°C. From the surface tension measurements, the critical micelle concentration (cmc) data were measured as a function of mixing composition. Cmc-values were then analyzed according to regular solution model. The composition of mixed micelles, the interaction parameter (β) and the activity coefficients were evaluated from the regular solution model for the all anionic-amphoteric mixed systems. The interaction parameter values indicated a synergistic interaction between DDAO and the three anionic surfactants at all mole fractions to be due to an overall attractive interaction in the mixed micelles. The strength of the interaction between the amphoteric surfactant and the sodium alkyl sulfate in three mixed systems obeys the following order: SDeS/DDAO > SDS/DDAO > STS/DDAO suggesting that the decrease in the length of anionic surfactant alkyl chain results in a stronger interaction with DDAO. On the other hand, the viscosity data reveals a viscosity increasing trend of STS/DDAO > SDS/DDAO > SDeS/DDAO.