Sodium Alkyl Research Articles

Size-Selective Phase-Transfer Catalysis with Interfacially Cross-Linked Reverse Micelles

Cross-linking of the reverse micelles (RMs) of a triallylammonium surfactant afforded organic nanoparticles with introverted cationic groups. The cross-linked reverse micelles catalyzed size-selective biphasic reaction between sodium azide and alkyl bromides. Size selectivity of up to 9:1 was obtained for alkyl bromides with similar structures. The selectivity was influenced strongly by the size of the water pool and proposed to happen as a result of the "sieving" effect of the alkyl corona.

Virucidal Effects of Bleach Activators, Sodium Alkyl Acyloxybenzene Sulfonate and Acyloxybenzoic Acid, Against Feline calicivirus

Noroviruses (NVs) are major causative pathogens of gastroenteritis. The disinfection of contaminated clothing during common household washing is desirable. The virucidal effects of 2 bleach activators, sodium alkyl acyloxybenzene sulfonate (OBS) and alkyl acyloxybenzoic acid (OBC), were studied using Feline calicivirus (FCV) as a surrogate for NVs. FCV was added to solutions containing either OBS or OBC and sodium percarbonate at various temperatures and for varying lengths of time. OBS and OBC, which generate long carbon chain peroxy acids, enhanced the virucidal effect of sodium percarbonate (PC). In particular, sodium lauroyloxybenzene sulfonate (OBS-12) and decanoyloxybenzoic acid (OBC-10) showed superior virucidal effects. Although the virucidal effect of 38-200 mg/L OBS-12 was maintained with 2-5% (v/v) horse serum, there was less of an effect with the same concentration of available chlorine. OBS and OBC have been used as ingredients in some laundry products to increase bleaching activity. It is expected that the use of OBS and OBC is also effective for the inactivation of NVs under common household washing conditions.

Study of the Reactivity of Na/Hard Carbon with Different Solvents and Electrolytes

The reactivity of sodium inserted hard carbon with ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), EC:DEC, EC:DMC and NaPF6 EC:DEC (/DMC) electrolytes was studied by Accelerating Rate Calorimetry (ARC), and the products after the ARC experiments were investigated by X-ray diffraction. The results show that sodium inserted hard carbon reacts with DMC to form sodium methyl carbonate, and that it reacts with EC and DEC to form sodium alkyl carbonates which apparently have a similar structure to sodium methyl carbonate. Sodium inserted hard carbon is more reactive with DMC and DEC than with EC. Finally, Na inserted hard carbon is more reactive in NaPF6 EC:DEC and NaPF6 EC:DMC than in EC:DEC and EC:DMC due to the high thermal stability of NaPF6 and preferential solvation of NaPF6 by EC, which leaves DEC and DMC available for reaction. The reactivity of Li inserted hard carbon was also compared to the reactivity of Na inserted hard carbon in both solvent and electrolyte and it was found that Li inserted hard carbon shows much better thermal stability.

Effect of the length of surfactant hydrocarbon radicals on the association of cationic polyelectrolytes with alkyl sulfates in water-alcohol solutions

The effect of the lengths of the alkyl radicals of sodium alkyl sulfates (decyl sulfate, dodecyl sulfate, and tetradecyl sulfate) on the association with partially quaternized poly(4-vinylpyridine) in wateralcohol solutions of different compositions is studied via potentiometry, viscometry, spectrophotometry, and dynamic light scattering. The critical concentrations of surfactant association, hydrodynamic radii, and molecular-mass characteristics of polyelectrolyte-surfactant associates are determined. The parameters of the surfactant-polymer cooperative association and the dissociation constants of the complexes are calculated. An increase in the lengths of the alkyl radicals results in enhanced associative interactions in the polyelectrolyte-surfactant system at ethanol concentrations below 34 vol %. In solutions with higher alcohol concentrations, the composition of the solvent plays the decisive role in polymer-colloid complexation.

Biological properties of sodium alkyl methyl ester sulfonate/alkyltrimethylammonium bromide surfactant mixtures

Quaternary ammonium compounds (QACs) are commonly used as disinfectant in medical care, food industry, detergents and glue industries. This is due to a small concentration of QACs is sufficient to inhibit the growth of various bacteria strains. In this work, the inhibitive power of cationic surfactants, alkyltrimethylammonium bromide (CnTAB) in the presence of anionic surfactants, sodium alkyl methyl ester α-sulfonate (CnMES) was studied. The growth inhibition test with gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria were used to determine the toxicity of single and mixed surfactants. Results from this work showed that certain mixed surfactants have lower minimum inhibition concentration (MIC) as compared to the single CnTAB surfactants. Besides that, it was also found that alkyl chain length and the mixing ratios of the surfactants play a significant role in determining the mixture inhibitive power.

Intramolecular Cycloaddition Reactions of 1‐Alkenyl‐3,4,5‐triaryl‐1,2‐diphosphacyclopenta‐2,4‐dienes

Abstract1‐Alkenyl‐3,4,5‐triaryl‐1,2‐diphosphacyclopenta‐2,4‐dienes obtained by alkylation of sodium 3,4,5‐triaryl‐1,2‐diphosphacyclopentadienide with Br(CH2)nCH=CH2undergo, depending on thenvalue, either an intermolecular Diels–Alder reaction leading to polymeric compounds (n= 1, 4) or intramolecular cycloaddition reactions to give tricyclic cage phosphanes with high regio‐ and stereoselectivity (n= 2, 3). The structures and conformational behavior of these new tricyclic phosphanes are discussed.

Characterizing the Distribution of Sodium Alkyl Sulfate Surfactant Homologues in Water-Based, Acrylic Pressure-Sensitive Adhesive Films

The distributions of three sodium alkyl sulfate surfactants in dry adhesive films cast from water-based latexes were characterized using confocal Raman microscopy (CRM) and contact angle (CA) and tack measurements. Sodium dodecyl sulfate (SDS), sodium tetradecyl sulfate (STS), and sodium octadecyl sulfate (SODS) were added to dialyzed commercial adhesive latex at various concentrations. Uneven distributions were found for all three surfactants along with a tendency to enrich film-air interfaces and, to a much lesser extent, film-glass interfaces. SDS demonstrated the greatest tendency to concentrate near film surfaces followed by STS and SODS. For all three surfactants, water CA values for dried films decreased sharply with increasing concentrations in the latex, but significant differences were observed, with SDS again having the greatest impact followed by STS and SODS. Tack of dried polymer films was also found to decrease with increasing latex surfactant levels, with SDS producing the sharpest drop as well as the lowest plateau values. Results indicate that interfacial enrichment by surfactants is detectable via both CRM and CA measurements, and this enrichment can significantly affect the performance of films. Finally, surface enrichment levels are qualitatively related to measures of the surfactants' affinity for aqueous solutions, as characterized by the logarithm of their 1-octanol-water distribution coefficients (K(ow)).

Emulsifing Properties of Sodium Alkyl Aryl Sulfonate to Alkanes

The abilities of sodium alkyl aryl sulfonate,which had high-purity and defined structure,to emulsify alkanes,were investigated by a water diversion method.Using liquid paraffin wax as the oil phase,the effects of the concentration of emulsion,length of alkyl chain,structures and locations of aryl groups in alkyl chain on emulsion stability were studied,and the best concentration of emulsion were determined.Meanwhile,the effects of different oil phases to emulsion stability were discussed.The experimental data showed that the best mass fraction of emulsion was 0.1%.With definite structures of aryl group,emulsion stability increased linearly with the increasing of the length of carbonic chain.When the length of alkyl chain on alkyl group was set,the emulsion stability was enhanced with the increasing of the length of alkyl chain on aryl group.With the aromatic ring shifts from the terminal to the center of the long alkyl chain,the emulsion stability increased.With the increase of molecular mass of oil phases,the molecular mass of emulsifier to achieve stable emulsifying liquid increased.

A comparison study between sodium dodecyl sulfate and sodium dodecyl sulfonate with respect to the thermodynamic properties, micellization, and interaction with poly(ethylene glycol) in aqueous solutions

The density, sound velocity, and conductivity measurements were performed on aqueous solutions of sodium dodecyl sulfate (C 12H 25SO 4Na) or sodium dodecyl sulfonate (C 12H 25SO 3Na) in the absence and presence of poly(ethylene glycol) (PEG) at different temperatures. Changes in the apparent molar volumes and isentropic compressibilities upon micellization were derived using a pseudophase-transition approach and the infinite dilution apparent molar properties of the monomer and micellar form of C 12H 25SO 4Na and C 12H 25SO 3Na were determined. Variations of the critical micelle concentrations (CMCs) of both surfactants in the solutions investigated with temperature were obtained from which thermodynamic parameters of micellization were estimated. It was found that at low temperature the micelle formation process is endothermic and therefore, this process must be entropically driven. However, upon increasing the temperature, the enthalpic factor becomes more significant and, at temperatures higher than 303.15 K the micellization is enthalpy driven. The interactions between C 12H 25SO 4Na/C 12H 25SO 3Na and PEG were studied and it was found that sodium alkyl sulfonates were seen to interact more weakly than their sulfate analogues.

Effect of protein–surfactant interactions on aggregation of β-lactoglobulin

The milk protein β-lactoglobulin (βLG) dominates the properties of whey aggregates in food products. Here we use spectroscopic and calorimetric techniques to elucidate how anionic, cationic and non-ionic surfactants interact with bovine βLG and modulate its heat-induced aggregation. Alkyl trimethyl ammonium chlorides (xTAC) strongly promote aggregation, while sodium alkyl sulfates (SxS) and alkyl maltopyranosides (xM) reduce aggregation. Sodium dodecyl sulfate (SDS) binds to non-aggregated βLG in several steps, but reduction of aggregation was associated with the first binding step, which occurs far below the critical micelle concentration. In contrast, micellar concentrations of xMs are required to reduce aggregation. The ranking order for reduction of aggregation (normalized to their tendency to self-associate) was C10–C12>C8>C14 for SxS and C8>C10>C12>C14>C16 for xM. xTAC promote aggregation in the same ranking order as xM reduce it. We conclude that SxS reduce aggregation by stabilizing the protein's ligand-bound state (the melting temperature tm increases by up to 10°C) and altering its charge potential. xM monomers also stabilize the protein's ligand-bound state (increasing tm up to 6°C) but in the absence of charged head groups this is not sufficient by itself to prevent aggregation. Although micelles of both anionic and non-ionic surfactants destabilize βLG, they also solubilize unfolded protein monomers, leaving them unavailable for protein–protein association and thus inhibiting aggregation. Cationic surfactants promote aggregation by a combination of destabilization and charge neutralization. The food compatible surfactant sodium dodecanoate also inhibited aggregation well below the cmc, suggesting that surfactants may be a practical way to modulate whey protein properties.

Self-Assembly, Foaming, and Emulsifying Properties of Sodium Alkyl Carboxylate/Guanidine Hydrochloride Aqueous Mixtures

Unsaturated fatty acids may be extracted from various agricultural resources and are widely used as soaps in the industry. However, there also exist a large variety of saturated and hydroxy fatty acids in nature, but their metal salts crystallize at room temperature in water, hampering their use in biological and chemical studies or for industrial applications. Addition of guanidine hydrochloride (GuHCl) to sodium salt of myristic acid has been shown to prevent its crystallization in water, forming stable flat bilayers at room temperature. Herein, we extend this finding to two other saturated fatty acids (palmitic and stearic acids) and two hydroxyl fatty acids (juniperic and 12 hydroxy stearic acids) and study more deeply (by using small angle neutron scattering) the supramolecular assemblies formed in both saturated and hydroxyl fatty acid systems. In addition, we take the advantage that crystallization no longer occurs at room temperature in the presence of GuHCl to study the foaming and emulsifying properties of those fatty acid dispersions. Briefly, our results show that all fatty acids, even juniperic acid, which is a bola lipid, are arranged in a bilayer structure that may be interdigitated. Depending on the nature of the fatty acid, the systems exhibit good foamability and foam stability (except for juniperic acid), and emulsion stability was good. Those findings should be of interest for using saturated long chain (and hydroxyl) fatty acids as surfactants for detergency or even materials chemistry.

WG and WP Formulations of Captan with Polymeric Surfactants

Abstract Water-dispersible Granules (WGs) and Wettable Powder (WP) are two important types of agrochemical formulations. The combined shares of WG and WP formulations by volume were 30 % among all the agrochemical formulation types in 2007. WG formulation is continuously increasing in share as a safer and greener formulation type. Both formulation compositions and formulation process affect the performance of WG and WP. This research demonstrated a concise and systematic approach to develop WG via low pressure extrusion process and WP blade-mixer blending process in the laboratory. Specifically, Captan technical as a model active ingredient was formulated together with polymeric dispersants, alkyl sodium sulfosuccinate wetting agents, and Kaolin clay diluents under controlled process conditions. The formulated samples were investigated in suspension stability, disintegration behavior, particle size, and granule morphology, and their composition-structure-performance relationships were discussed.

Rapid Screening of Volatile Ion-Pair Reagents Using UHPLC and Robust Analytical Method Development Using DoE for an Acetyl Cholinesterase Inhibitor: Galantamine HBr

As over 70% of pharmaceutical compounds are bases, the analysis of these basic compounds by high performance liquid chromatography (HPLC) continues to be of great value and interesting. Acetyl cholinesterase inhibitors (AChEIs), which contain the basic compounds like Rivastigmine tartrate, Galantamine hydrobromide and Donepezil with different polarities, were chosen for the study. A rapid screening of the volatile ion-pairing reagents was performed using modern techniques like ultra high performance liquid chromatography (UHPLC). The experiments were planned using the ‘Design of Experiments’ (DoE) approach to identify the LC–MS compatible ion-pair reagent. In this study, Heptafluorobutyric acid (HFBA) has given a very good peak shape with tailing factor at 1.4 and theoretical plates up to ~5,000 were observed, compared to tailing factor at 1.9 and theoretical plates up to ~3,000 with non-volatile ion-pair reagent sodium heptane sulphonate (SHS). Similarly retention with HFBA was optimum as ~5 min in short run time method compared to ~13 min with SHS. This ion-pair reagent has proved to be good replacement of sodium alkyl sulphonate modifiers. HFBA can also be used for semi-preparative work for isolation of impurities by just evaporating the solvents. It avoids the extraction of other inorganic modifiers.

Preparation of microencapsulated α-olefin drag reducing polymer used in oil pipeline transportation

Microcapsules containing oil drag-reducing polymer particles were prepared by melting-scattering and condensing of polyethylene wax, in-situ polymerization of urea and formaldehyde, and interfacial polymerization of styrene respectively. The related processes were studied by a molecular dynamics simulation method, and molecular design of microcapsule isolation agent was carried out on the basis of the simulation. The technologies for preparing microencapsulated oil drag-reducing polymer particles were compared and the circulation drag reducing efficiency of the microencapsulated polymer particles was evaluated based on the characterization results and their dissolution properties. Molecular design of a microcapsule isolation agent suggests that α-olefin polymer particles can be stably dispersed in water by using long-chain alkyl sodium salt surfactant which can prevent the agglomeration of α-olefin polymer particles. The results of simulation of the adsorption process shows that the amount of alkyl sodium salt surfactant can directly affect the stability of microencapsulated α-olefin polymer particles. and there must be a minimum critical amount of it. After characterization of the morphology by Scanning Electron Microscopy (SEM) and comparison of the static pressure stability, especially the conditions of reaction and technological control of microcapsules with different shell materials, microencapsulation of α-olefin polymer particles with poly-(urea-formaldehyde) as shell material was selected as the optimum scheme, because it can react under mild conditions and its technological process can be controlled in a large range. The relationship of drag reducing rate and dissolving time of microcapsules showed that the formation of microcapsules did not affect the maximum drag reducing rate, and the drag reducing rate of each sample can reach about 35% along with the dissolving time, i.e. microencapsulation did not affect the drag reducing property of α-olefin polymer.

THF hydrate crystal growth inhibition with small anionic organic compounds and their synergistic properties with the kinetic hydrate inhibitor poly(N-vinylcaprolactam)

Small, cationic tetraalkylammonium ions (particularly for alkyl=butyl or pentyl) are known to inhibit tetrahydrofuran (THF) and natural gas hydrate crystal growth and have been used as synergists for commercial kinetic hydrate inhibitor polymers (KHIs), such as N-vinylcaprolactam polymers, for a number of years. The ability for small, organic anionic molecules to inhibit (THF) hydrate crystal growth and their potential as KHI synergists in blends with poly(N-vinylcaprolactam) have been investigated. Several series of sodium alkyl carboxylates, sulphates and sulphonates were synthesised. It was found that none of these molecules were capable of inhibiting THF hydrate crystal growth as well as the best tetraalkylammonium salts. Alkyl carboxylates appeared to be more effective as inhibitors than the sulphonates or sulphates. The most effective anionic THF hydrate crystal growth inhibitors had butyl or pentyl groups, with alkyl branching at the tail (i.e. iso- rather than n-isomers) being advantageous. Anionic carboxylate molecules, particularly with isopentyl or isobutyl groups, showed some kinetic inhibition synergy with poly(N-vinylcaprolactam) lowering the onset and catastrophic hydrate formation temperatures in high pressure (78 bar) constant cooling experiments with Structure II hydrates by 1–2 °C when dosed at 2500 ppm compared with using 2500 ppm polymer alone. This synergism was however less than the best tetraalkylammonium salts (alkyl=n-butyl or n-pentyl) at the same test conditions. Sodium butyl sulphonate and sodium 4-methylpentanoate did not prevent hydrate agglomeration with 3.6% brine and decane at 25% water cut in stirred sapphire cells when dosed at 20,000 ppm based on the aqueous phase, whereas 10,000–20,000 ppm active material of several commercially available anti-agglomerants gave fine transportable slurries and no hydrate deposits at the same conditions.

Synthesis and characterization of an infinite sheet of metal–alkyl bonds: unfolding the elusive structure of an unsolvated alkali-metal trisalkylmagnesiate

The study of co-complexation reactions between NaCH(2)SiMe(3) and Mg(CH(2)SiMe(3))(2) has allowed the isolation and structural elucidation of the first solvent-free alkali-metal alkylmagnesiate [{NaMg(CH(2)SiMe(3))(3)}(∞)] (1) as well as the related solvent-free sodium alkyl [{(NaCH(2)SiMe(3))(4)}(∞)] (3).

Effect of surfactant alkyl chain length on the dispersion, and thermal and dynamic mechanical properties of LDPE/organo-LDH composites

Low density polyethylene/layered double hydroxide (LDH) composites were prepared via melt compounding using different kinds of organo-LDHs and polyethylene-grafted maleic anhydride as the compatibilizer. The organo-LDHs were successfully prepared by converting a commercial MgAl-carbonate LDH into a MgAl-nitrate LDH, which was later modified by anion exchange with linear and branched sodium alkyl sulfates having different alkyl chain lengths (nc = 6, 12 and 20). It was observed that, depending on the size of the surfactant alkyl chain, different degrees of polymer chain inter- calation were achieved, which is a function of the interlayer distance of the organo-LDHs, of the packing level of the alkyl chains, and of the different interaction levels between the surfactant and the polymer chains. In particular, when the number of carbon atoms of the surfactant alkyl chain is larger than 12, the intercalation of polymer chains in the interlayer space and depression of the formation of large aggregates of organo-LDH platelets are favored. A remarkable improvement of the thermal-oxidative degradation was evidenced for all of the composites; whereas only a slight increase of the crystallization temperature and no significant changes of both melting temperature and degree of crystallinity were achieved. By thermo- dynamic mechanical analysis, it was evidenced that a softening of the matrix is may be due to the plasticizing effect of the surfactant.

Structural Analysis of Protein Complexes with Sodium Alkyl Sulfates by Small-Angle Scattering and Polyacrylamide Gel Electrophoresis

Small-angle X-ray (SAXS) and neutron (SANS) scattering is used to probe the structure of protein-surfactant complexes in solution and to correlate this information with their performance in gel electrophoresis. Proteins with sizes between 6.5 to 116 kDa are denatured with sodium alkyl sulfates (SC(x)S) of variable tail lengths. Several combinations of proteins and surfactants are analyzed to measure micelle radii, the distance between micelles, the extension of the complex, the radius of gyration, and the electrophoretic mobility. The structural characterization shows that most protein-surfactant complexes can be accurately described as pearl-necklace structures with spherical micelles. However, protein complexes with short surfactants (SC(8)S) bind with micelles that deviate significantly from spherical shape. Sodium decyl (SC(10)S) and dodecyl (SC(12)S, more commonly abbreviated as SDS) sulfates result in the best protein separations in standard gel electrophoresis. Particularly, SC(10)S shows higher resolutions for complexes of low molecular weight. The systematic characterization of alkyl sulfate surfactants demonstrates that changes in the chain architecture can significantly affect electrophoretic migration so that protein-surfactant structures could be optimized for high resolution protein separations.

Formulating Middle Phase Microemulsions Using Extended Anionic Surfactant Combined with Cationic Hydrotrope

The phase behavior of systems containing sodium alkyl polypropylene oxide sulfate with equimolar ratio of polypropylene oxide ammonium chloride was determined as a function of salt concentration and alkane carbon number at ambient temperature. Visual inspection as well as cross polarizers were used to detect anisotropy. Solubilization ratios for oil and brine in the middle phases were measured and used to calculate the interfacial tension (IFT) between the microemulsion and oil or brine. The fish diagram is presented showing a minimum amount of 0.20 wt% surfactant needed to form the middle phase. Swelling increases with decreasing the alkane carbon number of the oil. Ultra low IFT values were predicted for the systems investigated.

A Highly Efficient Synthesis of Sulphonamide Derivatives in the Presence of N-Methyl-2-pyrrolidone

The sulphonamide derivatives are synthesized by two component condensation of alkyl bromide and sodium arylsulphonamide using N-methyl-2-pyrrolidone (NMP) as a reaction medium. This method results in high yields without the formation of unwanted side products, and expanding substrate scopes.