Effect of Interfacial Alcohol Concentrations on Oil Solubilization by Sodium Dodecyl Sulfate Micelles

Alcohol partitioning and its effect on oil solubilization in Winsor Type I microemulsion systems was investigated. The microemulsion systems consisted of sodium dodecyl sulfate (SDS), pentanol, isopropanol (IPA), and dodecane, with either deionized water or an aqueous solution of 50 mM CaCl(2). Alcohol partitioning between aqueous, oil, and interfacial phases of the microemulsion was described using a pseudophase model in which the alcohol was assumed to self-associate in the oil phase. Partitioning in these miroemulsions was consistent with pentanol self-association in the oil phase. IPA did not self-associate but co-associated with pentanol in the oil phase. IPA concentrations as high as 20 g/kg of water had no effect on pentanol partitioning. The partition coefficient for pentanol between aqueous and interfacial phases was about 220 on a mole fraction basis. However, pentanol saturated the interfacial phase at a mole ratio of 3 : 1 pentanol to SDS. Addition of pentanol beyond that sufficient to saturate the interface resulted in large amounts of pentanol partitioning into the oil, reaching concentrations in excess of 25 g dL(-1) of oil phase. Dodecane solubilization increased linearly with pentanol mole fraction in the interface up to the 3 : 1 pentanol-to-SDS saturation level. The fact that dodecane solubilization was unaffected by pentanol at concentrations beyond those necessary for interfacial saturation suggests that pentanol behaves as a cosurfactant and not a cosolvent in these microemulsion systems. Copyright 2000 Academic Press.     

Phase Behavior of Tweens/Toluene/Water Microemulsion Systems for the Solubilization Absorption of Toluene

The purpose of the present study was to formulate microemulsion systems comprised of polyoxyethelene sorbitan ester surfactants (Tweens) + cosurfactant + water + oil (toluene) and to investigate their potential use as absorbents for the removal of toluene from air. Toluene is an example of a volatile organic compound (VOC). The microemulsions formed are stabilized by the nonionic surfactants (Tweens) and toluene. The results indicate that Tween-60 is superior to other Tween surfactants, and the optimum value for the hydrophile-lipophile balance (HLB) is 15. The performances of the cosurfactants followed the order n-butylamine>alcohol>butyric acid. The experimental results showed that the HLB value is more meaningful than the Bansal, Shah, O’Connell (BSO) equation for representing microemulsion systems. Comparative tests of this new absorbent system were performed in a double-stirred reactor, and the experimental absorption results were consistent with the phase diagram. Nonionic surfactant microemulsions have a significant absorption enhancement for toluene, as indicated by as much as 80.81% of toluene being present in the phase composition diagram, which thus have great prospects in air pollution remediation.     

Partial Phase Diagrams in the System Water/Formamide/Sodium Dodecyl Sulfate/Decanol

The phase regions were determined in the systems of sodium dodecyl sulfate, decanol and a polar solvent. The latter was a) water, b) water and formamide (1/1 weight ratio) and c) formamide

The water system showed an aqueous micellar solution, a decanol solution with inverse micelles as well as a lamellar and a hexagonal liquid crystal. The formamide system gave a formamide solution, a lamellar liquid crystal and a decanol solution while the system with water plus formamide in a 1/1 ratio still retained the hexagonal liquid crystal.     

十二烷基硫酸钠微乳色谱体系中pH值对其电渗流行为与微结构的影响

以十二烷基硫酸钠(SDS)/正己烷/正丁醇/硼砂微乳液为毛细管电色谱运行研究体系,以甲醇峰为微乳体系电渗流峰(EOF),考察不同pH值条件下微乳体系电渗流出峰时间(tEOF)和变化趋势.以微乳液滴粒径和ξ电位考察pH值对SDS缓冲溶液微乳体系微结构的影响,用微乳体系的电导值分析pH值条件下微乳液滴与氢氧根离子之间的相互...     

The Catalysis of Sodium Dodecyl Sulfate／1-Pentanol／Water W／O Microemulsion on the Photoisomerization of trans-Stilbene

The photoisomerization of trans-stilbene was studied in the water in oil (W/O) microemulsion formed by SDS (sodium dodeeyl sulfate), n-C5H11OH (1-pentanol) and H2O. The experimental results show that after 2-minute UV-irradiation, the yield of cis-stilbene is higher in W/O mieroemulsion than in homogeneous solvent-n-C5H11OH.     

Effect of Pentanol Partitioning on Solubilization of Tetrachloroethylene and Gasoline by Sodium Dodecyl Sulfate Micelles

The effect of interfacial pentanol concentrations on solubilization of tetrachloroethylene (PCE) and gasoline by sodium dodecyl sulfate (SDS) micelles was compared to that for dodecane solubilization, which had been measured in a previous study. The solubilization of PCE and gasoline reached their maximum values at a 1 : 3 SDS-to-pentanol molar ratio in the interface. As pentanol concentrations increased beyond that necessary for interfacial saturation, solubilization of PCE and gasoline decreased. This behavior was similar to that observed when dodecane was the oil phase. Electrical conductivity of aqueous SDS/pentanol solutions followed a trend similar to that for oil solubilization, reaching a maximum value at a 1 : 3 molar ratio of SDS to pentanol in the interface. The results of this and previous studies suggest that pentanol partitioning in SDS micelles can be described by a simple two-region model: Region I is the interface between the water-continuous phase and oil and Region II is the micelle inner core. When the mole fraction of pentanol in the interface is less than 0.75, pentanol partitions strongly into Region I, where it acts as a cosurfactant along with SDS and enhances oil solubilization. Above 0.75 mole fraction in the interface, pentanol partitions strongly into Region II, where it acts as a polar oil and competes with other oils for solubilization. Copyright 2001 Academic Press.     

Phase Diagrams and Solubilization of Chlorocarbons in Chlorocarbon/Water/Anionic Surfactant/Alcohol Microemulsion Systems

The solubilization abilities of various chlorocarbons were investigated in a middle phase microemulsion system anionic surfactant sodium dodecyl sulfate (SDS) or sodium dodecyl sulfonate (AS)/n-butanol/chlorocarbon/brine with a ε-β fishlike phase diagram. The composition of the balanced interfacial layer of the microemulsion and some other parameters are calculated. The result shows that surfactant little dissolves in water and chlorocarbon phases, while alcohol mainly dissolves in water and oil phases besides in the interfacial layer. The order of the solubilization ability is dichloromethane (CH₂Cl₂) ～ carbon tetrachloride (CCl₄) > tetrachloroethylene (PCE) > o-dichloro-benzene. The solubility of the alcohol decreases with the increase in NaCl concentrations, which should be compensated by the increase in the amount of alcohol as cosolvent (Cs), so as to maintain the balanced interfacial layer. Salinity has little effect on the partition of surfactant between phases.     

Creaming and Rheology of Oil-in-Water Emulsions Containing Sodium Dodecyl Sulfate and Sodium Caseinate

The kinetics of bridging flocculation of polystyrene latex (PSL) particles induced by addition of excess polyethylene oxide (PEO) in the initial stage was studied using standardized mixing flow generated in an end-over-end rotation apparatus. To clarify the effect of the rate of polymer supply, flocculation experiments were performed by changing polymer concentration (C(p)). As was found in previous investigation, the progress of flocculation is divided into two stages. The first stage is characterized by an enhancement of the rate of flocculation by polymer addition. The increase in polymer concentration results in a higher enhancement but in a shorter duration for this stage. In the second stage, the flocculation is essentially stopped due to the appearance of steric stabilization. It was found that the ultimate degree of flocculation goes through a maximum against C(p). That is, when C(p)>==1.0 ppm, the ultimate degree of flocculation decreases with increased C(p). In this region, a clear crossover from the first stage to the second stage was observed. In the extreme case, evidence of a slight setback of flocculation was confirmed, which implies the breakup of metastable bridges by the application of additional fluid shear. When C(p)<==1.0 ppm, the ultimate degree of flocculation decreases with decreased C(p). The crossover from the first stage to the second stage appears more gradual at lower C(p). These results were observed irrespective of ionic strength. This result was interpreted as the elimination of a bare surface due to the spreading of a steric layer of adsorbed polymer. The characteristic time for reconformation of the polymer at a bare colloidal surface was estimated to be a few seconds. Copyright 2000 Academic Press.     

十二烷基硫酸钠对聚乙烯醇亚浓水溶液流变行为的影响

表面活性剂会影响聚乙烯醇(PVA)分子间及分子内氢键形成,进而改变其水溶液的流变响应.本文在确定十二烷基硫酸钠(SDS)在PVA亚浓水溶液中的临界聚集浓度(CAC)和临界胶束浓度(CMCP)基础上,考察了SDS对PVA亚浓溶液(10 wt%)流变行为的影响.研究发现,不同浓度SDScsur对PVA水溶液稳态流变行为的影响差异较大:(1)当csur CMCP,随着csur增加,胶束起物理交联点作用,ηa增大,复合溶液的动态储能模量亦显著增大.加入SDS后,PVA体系内结合水的数目降低,但当csur> CMC后,结合水的数目几乎不变,黏流活化能也表现出相近的变化规律.与稀溶液相比,SDS对PVA亚浓溶液的降黏幅度较大.     

静电场诱导十二烷基硫酸钠结晶行为的研究

用透射电镜、X射线衍射及DSC等方法 十二烷基硫酸钠（SDS）极稀水溶液（溶液介于临界聚集浓度和临界胶束浓度之间）在静电场作用下的结晶行为,静电场作用诱导SDS形成规则的四方单晶与从甲醇中重结晶所得样品的晶体结构相同,DSC结果表明,从有序到无序结构变化的一级相转变热焓相同,但由于电场诱导结晶的晶体较小而表现为转变温度的降低,没有施加静电场处理的样品只具有较低的有序程度。     

Dynamic Interfacial Tension Behavior of Water/Oil Systems Containing In situ-Formed Surfactants

Time-dependent interfacial tension (IFT) has been investigated for an interfacially reactive immiscible system composed of model-acidified oil and alkaline water. The acidified oil was composed of either lauric acid or linoleic acid dissolved in n-dodecane. Drop volume tensiometry was employed to measure the interfacial tension between the two phases. In the case of lauric acid, the IFT value was found to decrease sharply with increasing alkali concentration, even at low drop formation times. In the case of linoleic acid, the IFT decrease with the drop formation time was more gradual, especially at low alkali concentration. The rate of formation of the interfacial area was also found to be dependent on alkali concentration.     

十二烷基硫酸钠对甲烷水合物生成过程影响研究

根据甲烷水合物含气率高、分解速度慢等特性,提出利用高压注水技术和表面活性剂促进作用促使矿井瓦斯水合化以预防煤与瓦斯突出的思路。进行了3·6~12℃、7·82~12·26MPa条件下两种浓度体系(10mmol/L和0·3mmol/L)中十二烷基硫酸钠(SDS)对甲烷水合物作用效果的实验研究,结合水合物诱导时间、生成速度及含气率等计算对实验数据进行了分析,并运用表面张力法测得8℃时SDS溶液的临界胶束浓度(CMC)为2·5mmol/L。结果表明,高浓度体系对水合物生成速度、含气率的影响较之低浓度体系的更强,但是低浓度体系中水合物生成的诱导时间却较短,表面活性剂溶液浓度超过其CMC后对水合物的生成影响显著。     

The Effect of Macromolecules on Foam Stability in Sodium Dodecyl Sulfate/Cetylpyridinium Bromide Mixtures

Abstract

The effects of macromolecules, gelatin, and polyvinylpyrrolidone (PVP), on the properties of foam comprising sodium dodecyl sulfate (SDS) and cetylpyridinium bromide (CPDB) have been studied by measurements of foamability, foam stability, surface tension, and solution specific viscosity. The results indicate that foamability and foam stability are significantly improved when macromolecules are added into mixed systems. Both gelatin and PVP associate with SDS/CPDB surfactants and form aggregates. Electrostatic repulsion and steric stabilization between the two sides of the foam lamellae, due to aggregation, and prevention of drainage in the lamellae, achieved by the long chains of macromolecules are the reasons for increasing foamability and foam stability. The interactions between PVP and surfactants is weaker than those between gelatin and surfactants. The strongest association between macromolecules and surfactants occurs when the molar ratio of SDS/CPDB is 1:1. By comparing PVP with gelatin, the former is favored to increase foamability, and the latter is favored to increase foam stability.     

Effect of a Weak Electrolyte on the Critical Micellar Concentration of Sodium Dodecyl Sulfate

The critical micellar concentration of sodium dodecyl sulfate is strongly altered bytris(hydroxy-methyl)methylammonium ions. The effect of buffer solutions containing this weak electrolyte as the counterion source has been studied using various concentrations of the acid–base system as well as modifying the pH. Results show that counterion concentrations ranging from 0 to 340 × 10⁻³M induce an appreciable diminution of the critical micellar concentration from 8 to 0.7 × 10⁻³M. The analysis of data suggests that the critical micellar concentration of sodium dodecyl sulfate depends on the concentration of weak electrolytes in a way very similar to that of strong electrolytes.     

Temperature Effect on the Phase Behavior of the Systems Water/TritonX-100,114,405/n-Butanol/n-Hexane

We have investigated the effect of temperature on the phase behavior and the partition coefficients of nonionic surfactants in water/n-hexane systems. We found that the composition of the conjugate single and two phase solution in the pseudoternary diagram is continuously transformed from one state to other by increasing the temperature. We also demonstrated that the partition coefficient of a nonionic surfactant is a measure of the relative hydrophilic-lipophilic nature of the surfactant, if the measurement is performed at low concentration.     

Diffusion Coefficients In a Water/Sodium Dodecyl Sulfate/ Penlanol Mlcroemulslon Base and Its Ammonium Hydroxide Analogue

The self-diffusion coefficients were determined in sodium dodecyl sutfale/pcnlanol solutions with water and an aqueous concentrated ammonium hydroxide solution using NMR.

Replacing water by the ammonium hydroxide solution destabilized the liquid crystalline phase in the system and also reduced the size of the colloidal association structures in the isotropic liquid part.     

用碱性艳蓝BO分光光度法测定水中十二烷基苯磺酸钠和十二烷基硫酸钠

1　引　　言合成洗涤剂的广泛使用对水环境造成影响 ,阴离子表面活性剂 (ＡＳ)的含量是各类水质的一项重要检测指标 ,国内外均推荐亚甲基蓝分光光度法。我们将市售商品化碱性艳蓝ＢＯ(染料商品名 )染料提纯后作为显色剂 ,研究了该显色剂与ＡＳ的显色反应。在Ｈ3ＰＯ4 ＮａＨ2 ＰＯ4介质中 ,乳化剂ＯＰ作稳定剂 ,碱性艳蓝ＢＯ分光光度法直接测定河水中的十二烷基苯磺酸钠和十二烷基硫酸钠。方法具有灵敏、快速、简便、准确等优点 ,水样无需萃取、浓缩 ,即可测定。2　实验部分2 1　仪器及试剂　 72 1型分光光度计 (上海精密科学仪器有限公司 …     

Extraction by Mixed Solvent and Spectrophotometric Determination of Sodium Dodecyl Sulfate in Sea Water

Mixed solvent was used to extract ion pairs formed from suitable cationic dye and sodium dodecyl sulfate in sea water. The extracts were used for spectrophotometric determinations. The extraction of ion pairs of various combinations is discussed. Ethyl violet and a mixture (1:1) of p-xylene and toluene are the most useful combination as the cationic dye and the extraction solvent. The extracts were determined spectrophotometrically at 611.2 nm; the molar absorptivity is 1.27 × 10⁵ M^?1 cm^?1. The detection limit is 2.0 ppb in water based on three times the standard deviation of the blank. Extraction with this mixed solvent is as rapid and sensitive as with the best single solvent.     

Fluorescence Quenching of Anthracene by N,N-Diethylaniline in the Sodium Dodecyl Sulfate/Benzyl Alcohol/Water System

Photoinduced electron-transfer reaction of anthracene with N,N-diethylaniline (DEA) was studied in the SDS (sodium dodecyl sulfate)/BA (benzyl alcohol)/H₂O system. In an oil/water microemulsion, only the excited anthracene located at the interface can be quenched by DEA. In a water/oil microemulsion, this quenching reaction occurs in the BA continuous phase. Besides being the quencher of the excited anthracene, DEA could also change the system's structure.     

A Study of the Solubilization of Polar Oily Materials by Alkyl Polyglucoside and Sodium Dodecyl Sulfate in Mixed Surfactant System

The effects of different alkyl chains of nonionic surfactants and solubilized polar oily material on the solubilizing capacity of binary anionic‐nonionic mixed surfactant systems were studied. This system includes surface tension measurements to determine the critical micelle concentration. Results were analyzed using regular solution theory to obtain the mixed micelle and the interaction parameter β, in order to evaluate the type of interactions of surfactants in the mixed micelle. Solubilizing capacity has been investigated by measuring the optical density of solubilized polar oily materials like octanol, decanol, and dodecanol. The solubilizing phenomenon exhibited by mixed surfactants systems showed better results than that of the individual surfactant system. The amount of solubilization in mixed surfactant increases with increase in carbon chain length of alkyl polyglucoside.