Effect of Surfactants and Ionic Strength on Dissociation of Hydrochlorides of Phenothiazine Derivatives

Abstract

A study of the effect of the anionic surfactant dodecyl sulfate, the cationic surfactant carbethoxypentadecyl trimethyl ammonium bromide (Septonex), nonionic surfactant p-octyl phenyl polyoxyethylene (Triton X-100), and a strong electrolyte (KBr) on the dissociation of the hydrochlorides of two derivatives of phenothiazine (diethazine and fluphenazine) was made. It was found that sodium dodecyl sulfate increases the pKa value, whereas Septonex and Triton X-100 decrease this value. The presence of KBr suppresses the effect of the surfactants. A new method for the potentiometric determination of fluphenazine in an aqueous medium was proposed.     

1H NMR relaxation of water: a probe for surfactant adsorption on kaolin

In this study, (1)H NMR is used to investigate properties of sodium dodecyl sulfate (SDS), tetradecyl trimethyl ammonium bromide (TTAB), and dodecyl trimethyl ammonium bromide (DTAB) adsorbed on kaolin by NMR T(1) and T(2) measurements of the water proton resonance. The results show that adsorbed surfactants form a barrier between sample water and the paramagnetic species present on the clay surface, thus significantly increasing the proton T(1) values of water. This effect is attributed to the amount of adsorbed surfactants and the arrangement of the surfactant aggregates. The total surface area covered by the cationic (DTAB and TTAB) and anionic (SDS) surfactants could be estimated from the water T(1) data and found to correspond to the fractions of negatively and positively charged surface area, respectively. For selected samples, the amount of paramagnetic species on the clay surface was reduced by treatment with hydrofluoric (HF) acid. For these samples, T(1) and T(2) measurements were taken in the temperature range 278-338 K, revealing detailed information on molecular mobility and nuclear exchange for the sample water that is related to surfactant behavior both on the surface and in the aqueous phase.     

Effect of surfactant chain length on the binding interaction of a biological photosensitizer with cationic micelles

Steady-state and time-resolved fluorometric techniques have been exploited to study the photophysical and distribution behavior of an efficient cancer cell photosensitizer, norharmane (NHM), in well-characterized, biomimicking nanocavities formed by cationic micelles with varying surfactant chain length. Amphiphiles like dodecyl trimethyl ammonium bromide (DTAB), tetradecyl trimethyl ammonium bromide (TTAB), and cetyl trimethyl ammonium bromide (CTAB) have been used for the purpose. Emission behavior of NHM is very much dependent on the surfactant concentration as well as their hydrophobic chain length. The binding constant (K) and free-energy change (DeltaG) for the interaction of NHM with the cationic micelles have been determined from the fluorescence data. Polarity of the microenvironment around the probe has been determined in the cationic micellar environments from a comparison of the variation of fluorescence properties of the two-prototropic species of the probe in water/dioxane mixture with varying composition. Experimental results demonstrate that the variation in the cationic surfactant chain length plays an important role in promoting a specific prototropic form of the probe molecule. Fluorescence decays are biexponential in all the micelles indicating that the probe molecules are distributed between the two distinct regions of the micelles. The population of the component with a longer lifetime corresponds to the probe in the head group site, while the short-lived component comes from the probe bound to the core region of the micelles. On the basis of the lifetime measurements, the partitioning behavior of the chromophore in the head group and in the core regions in the micelles has been determined.     

不同有机离子表面活性剂改性蒙脱土结构与性能比较

分别用阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）、阴离子表面活性剂十二烷基磺酸钠(SDS)以及二者混合物(CTAB-SDS)的水溶液处理天然蒙脱土。 用红外光谱和X射线衍射比较了它们对蒙脱土结构的影响。 证明CTAB及CTAB-SDS处理蒙脱土的层间距分别由1.5420 nm增大至2.1946和1.8935 nm。 表明CTAB插入蒙脱土层间,且CTAB及CTAB-SDS处理蒙脱土在苯乙烯中分散性能明显提高,对有机物表现出良好的吸附性;而阴离子表面活性剂未进入蒙脱土层间,蒙脱土的结构和性能几乎未变。     

有机改性膨润土对己唑醇水悬浮体系物理稳定性的影响

利用4种季铵盐阳离子表面活性剂（十二烷基二甲基苄基氯化铵(1227)、十四烷基二甲基苄基氯化铵(1427)、十六烷基三甲基氯化铵(1631)和十八烷基三甲基氯化铵(1831)）分别对钠基膨润土（Na-Ben）进行有机改性,制得4种有机膨润土（1227-Ben、1427-Ben、1631-Ben和1831-Ben）并进行了红外光谱及X射线分析,考察了4种有机膨润土在水中的悬浮性能及对5%己唑醇水悬体系物理稳定性能的影响。 FT-IR及XRD分析结果表明,供试季铵盐阳离子的有机碳链均进入到膨润土的片层间。 水中悬浮性能测定实验表明,1831-Ben在水中悬浮性能相对较好,而其它3种均不理想,特别是1227-Ben和1427-Ben表现出强烈的斥水现象。 沉降试验表明,有机膨润土的使用有助于5%己唑醇水悬浮剂物理稳定性的提高,其中用1831-Ben制备出的水悬浮体系的物理稳定性明显优于其它3种,制剂析水率最低,屈服值与粘度最大,体系悬浮率最高,可见1831-Ben可以用作5%己唑醇水悬浮剂的抗沉降剂。     

Interfacial molecular array behaviors of mixed surfactant systems based on sodium laurylglutamate and the effect on the foam properties

The foam properties of mixtures of an eco-friendly amino-acid derived surfactant sodium lauroylglutamate (LGS) interacting with cationic surfactant dodecyl trimethyl ammonium bromide (DTAB), nonionic surfactant laurel alkanolamide (LAA) and anionic surfactant sodium dodecyl sulfonate (SDS), were investigated, respectively. It was amazing that the three investigated binary-mixed systems all showed obviously synergism effect on foaming, though LGS/DTAB catanionic mixture showed remarkable synergistic effect with no surprise. The equilibrium and dynamic surface activity, along with the interfacial molecular array behaviors of binary-mixed systems with different molar ratios at air/water surface were also studied. Moreover, the theoretical simulation was employed to investigate how the interfacial behaviors of surfactants at air/water surface affected the foam properties. The study might provide the meaningful guidance for utilizing the LGS-based systems, especially in constructing eco-friendly foam systems in the application areas of cosmetics, medicine and detergent.     

Properties of the Nanoscale Hydrophilic Cationic Pigment Based on Quaternary Surfactant

Dispersions of four nanoscale hydrophilic cationic pigments were prepared by micro jet milling process, in which the dodecyl trimethyl ammonium chloride (DTAC), tetradecyl trimethyl ammonium chloride (TDAC), hexadecyl trimethyl ammonium chloride (CTAC), and octadecyl trimethyl ammonium chloride (STAC) were used as the dispersers respectively. Zeta potential, particle size, viscosity and dispersion stability were tested. The effect of the hydrophobic chain of cationic quaternary surfactant on pigment dispersion's properties was discussed. The results showed that good dispersion effects were obtained when the hydrophobic chain were 14 or 16.     

Effects of addition of anionic and cationic surfactants to poly(N-isopropylacrylamide) microgels with and without acrylic acid groups

The interaction of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant hexadecyl trimethyl ammonium bromide with poly(N-isopropylacrylamide) (PNIPAAM) microgels with and without poly(acrylic acid) (PAA) was investigated by means of dynamic light scattering (DLS), zeta potential, and turbidimetry measurements. The DLS results show that the PNIPAAM microgels with PAA will contract when an anionic or cationic surfactant is added to the suspension, while the PNIPAAM microgels without PAA expand in the presence of an ionic surfactant. A collapse of the PNIPAAM microgels is observed when the temperature is increased. From the zeta potential measurements, it is observed that the charge density of PNIPAAM microgels in the presence of an ionic surfactant is significantly affected by temperature and the attachment of the negatively charged PAA groups. The turbidity measurements clearly indicate that the interaction between PNIPAAM and SDS is more pronounced than that of the cationic surfactant.     

Encapsulation of Bromothymol Blue into a Polysiloxane Network Matrix in Presence of Surfactants

Bromothymol blue (BTB) pH indicator was encapsulated into polysiloxane network using the sol-gel process. Transparent monolithic disks of entrapped BTB were obtained in the presence of cetyl trimethyl ammonium bromide (CTAB) or dodecyl dimethyl amino oxide (Genaminox LA, GLA) surfactant. Ultraviolet visible spectra showed that the encapsulated BTB retains its structure in terms of its response to pH. The kinetic studies reveal that there was a faster response to pH in the case of GLA surfactant than in the case of CTAB. It is found that the co-entrapment of cationic surfactant CTAB or zwitterionic surfactant GLA with TEOS has shifted the equilibrium of the BTB to the ionized form due to the electrostatic interaction between the surfactant and the BTB anion and therefore the base form becomes more pronounced (e.g., shift from yellow to red) than that of sol-gel matrix without surfactant.     

Binary Coalescence of Water Drops in Organic Media in Presence of Ionic Surfactants and Salts

Binary coalescence of water drops in o‐xylene and toluene, and ethylene glycol drops in toluene were studied in this work. The effects of cationic and anionic surfactants on coalescence time were studied. Cetyl trimethyl ammonium bromide (CTAB) and cetyl pyridinium bromide (CPyBr) were used as cationic surfactants. Sodium dodecyl benzene sulfonate (SDBS) was used as the anionic surfactant. The effects of salts (NaCl and CaCl₂) containing monovalent and divalent ions on coalescence were investigated. The coalescence time was found to follow distributions in each of these experiments. The minimum and maximum values of the distributions were largely different. The stochastic model developed earlier by us was used to fit the distributions. The effects of the physical properties of the system (such as density, size of the drops, interfacial tension, and surface excess of adsorbed surfactant) on the model parameters were discussed.     

混合表面活性剂水溶液的浊点性质

正负离子表面活性剂混合体系在水溶液中很容易形成沉淀,这曾在很大程度上限制了该体系理论性质的研究及其应用。近年来的研究发现,该体系在吸附和胶团形成等方面存在很强的协同效应,对其相关性质的研究越来越多。与单一离子性表面活性剂性质不同,后者的溶解     

二元阴阳离子表面活性剂法合成介孔氧化硅囊泡

以十二烷基磺酸钠(SDS)和十六烷基三甲基溴化铵(CTAB)为表面活性剂, 在SDS与CTAB的摩尔比为1.0~2.3时, 以正硅酸乙酯(TEOS)为硅源, 在氨水-水体系中于68℃下合成介孔氧化硅囊泡. 通过透射电子显微镜(TEM)、 X射线衍射仪(XRD)、 热重分析仪(TGA)和氮气吸附-脱附实验仪对合成的产物进行表征. 结果表明, 合成的产物为介孔氧化硅囊泡聚集体, 孔径约为4 nm, 样品的Brunauer-Emmett-Teller(BET)比表面积为826 m²/g. 对介孔氧化硅囊泡的形成机理做了初步探讨.     

表面活性剂对碳纳米管分散性及其湿法纺丝纤维性能的影响

碳纳米管(CNT)纤维因具有低密度、高强度以及高电导率等特性受到广泛关注。在湿法纺丝技术制备CNT纤维的工艺中，探究纺丝分散液和纺丝条件对CNT纤维性能的影响具有重要意义。本文研究了十二烷基硫酸钠(SDS)、十六烷基三甲基溴化铵(CTAB)、胆酸钠(SC)、牛磺脱氧胆酸钠(STDC)等表面活性剂对CNT纤维制备及性能的影响。通过拉曼光谱、紫外可见光谱、偏光显微镜、旋转流变仪、扫描电镜等方法对材料进行表征，以拉伸测试和“四探针”法对材料性能进行测试。结果表明，单壁碳纳米管(SWNTs)在表面活性剂的2(wt)%水溶液中的分散能力顺序依次为STDC> SC> CTAB> SDS;SDS或CTAB修饰的SWNTs分散液无法纺制纤维，SC和STDC修饰的SWNTs分散液具有良好的可纺性。其中以STDC作表面活性剂制备的CNT纤维性能最好，其断裂强度为160MPa,杨氏模量为12.3GPa,电导率为2300S/cm。     

The modification of the triple helical structure of gelatin in aqueous solution 3. The influence of cationic surfactants

The interaction between cationic surfactants (hexadecyl and dodecyl trimethyl ammonium bromide) and gelatin was characterized by measuring the circular dichroism. The interaction between the cationic surfactants and gelatin is weak in comparison to that of anionic surfactants. When the concentration of cationic surfactants is sufficiently low, refolding of the gelatin-strands to the triple helical structure by rechilling the solution from 298 K to 283 K is complete. The triple helical content of the solution is affected more strongly by the cationic surfactants in acidic solution than at pHs 7 or 10. The interaction depends on the apolar group of the surfactant and is found to be stronger for DTAB than for CTAB at 298 K. Coagulation of the hydrophobic gelatin-cationic surfactant complexes does not comprise that pan of gelatin which is able to refold the triple helical structure. Therefore, the gelatin-strands of lower molecular weights are thought to react favorably with the surfactant ions.     

Sol–gel encapsulation of cresol red in presence of surfactants

Cresol Red (CR) pH indicator was encapsulated into silica network using the sol–gel process. Transparent monolithic disks of entrapped CR were obtained in the presence of cetyl trimethyl ammonium bromide (CTAB) or dodecyl dimethyl amino oxide (Genaminox LA,GLA) alkyl hydroxyethyl dimethyl ammonium chloride (HY, R = 12–14) and TX-100 surfactants. UV/VIS spectra showed that the encapsulated CR retains its structure in terms of its response to pH. At the neutral conditions it is found that the HY surfactant is considered as proton donor as favor the cationic form of the indicator, while CTAB surfactant favor the neutral, however GLA surfactant, the anionic form of CR is more favored because GLA has a zwitterionic head. The surfactant GLA with TEOS has shifted the equilibrium to the ionized form of CR due to the electrostatic interaction between the surfactant and the CR anion. Therefore their pH range is dependent on the nature of a surfactant used. It is found that the HY surfactant is more efficient as far as loading of CR is concern and it widened the working pH range.     

Effect of Polymer and Surfactant‐Polymer Couples on the Acid-Catalyzed Hydrolysis of Phenyl Urea

The mechanism of the hydrolysis decomposition of phenyl urea in acid, polymer, and surfactant‐polymer media was investigated, the addition‐elimination mechanism with rate determining attack of water at N‐protonated substrate having already been studied. This study has introduced the polymer PEG (MW‐400) and (surfactant‐polymer) (ceteyl trimethyl ammonium bromide‐poly ethylene glycol) (CTAB‐PEG), (cetyl pyridinium bromide‐polyethylene glycol) (CPC‐PEG) (sodium dodecyl sulphate‐poly ethylene glycol) (SDS‐PEG), (Triton X‐100‐poly ethylene glycol) (TX‐100‐PEG), and (Brij35‐poly ethylene glycol) (Brij35‐PEG) in acid media. The results indicate that the presence of polymer and surfactant‐polymer enhances the rate of reaction at 80°C in the presence of 0.9 M H₂SO₄. Kinetic studies show that the reaction obeyed first‐order kinetics. The reaction kinetics can be well explained by micellar catalysis models like the PPIE.     

Interaction of Quercus Infectoria Natural Dye with Cationic and Anionic Surfactants: Adsorption/Micellization of Dye

The interaction of Indian natural dye, that is, Himalaya (Quercus infectoria) with cationic surfactant (cetyl trimethyl ammonium bromide) and anionic surfactant (sodium lauryl sulphate) has been studied. The spectrophotometric data showed an interaction between the natural dye and surfactants. Critical micelle concentration (CMC) of the surfactants, determined by measurement of specific conductance and surface tension methods, was found to be increase in case of anionic surfactant while that was found to decrease in case of cationic surfactant. Thermodynamic and surface parameters showed domination of micellization of dye in case of cetyl trimethyl ammonium bromide and domination of adsorption of dye in case of sodium lauryl sulphate.     

Kinetics of the M-Intermediate in the Photocycle of Bacteriorhodopsin upon Chemical Modification with Surfactants

The spectroscopic and kinetic studies of the interaction between bacteriorhodopsin in the M-intermediate and several surfactants (cetyl trimethyl ammonium bromide, dodecyl trimethyl ammonium bromide, diethylene glycol mono-n-hexyl ether, ethylene glycol mono-n-hexyl ether, sodium 1-decanesulfonate and sodium 1-heptanesulfonate) have been investigated using steady-state UV–VIS spectrometry and time-resolved absorption techniques. The steady-state spectral results show that bR retains its trimeric state. Time-resolved observations indicate that the rate of deprotonation of the protonated Schiff base increases in the presence of the cationic surfactants, whereas insignificant changes are observed in the neutral or anionic surfactants. The rate of the reprotonation of the Schiff base in the transition M → N is accelerated in anionic and neutral surfactants, but is decelerated in the presence of the cationic surfactants. Surfactants with a longer hydrocarbon tail have a greater effect on the kinetics when compared with surfactants having shorter hydrocarbon tails. The opposite effect is observed when the hydrophilic head of the surfactants contains opposite charges. These distinct kinetics are discussed in terms of the difference in the modified surface hydrophilicity of the bR and the possible protein configurational changes upon surfactant treatments.     

Suppression of surfactant interferences in anodic stripping voltammetry by sodium dodecyl sulfate

It was investigated whether interferences from surfactants in anodic stripping voltammetry (ASV) could be remedied by the anionic surfactant sodium dodecyl sulfate (SDS) which causes little or no interference in itself. Cadmium and lead were used as test analytes, and measurements were performed in acetate buffer as well as in 0.1 M HNO₃. One hundred parts per million of the interfering surfactant was added. SDS eliminated severe interference from the non-ionic surfactants Triton^© X-100 and dodecyl octaethylene glycol ether as well as from the polymer polyethylene glycol 6000 and from the cationic surfactant cetyl trimethyl ammonium bromide. SDS could not remedy the extraordinarily severe interference from the cationic surfactant cetyl pyridinium chloride. Two anionic surfactants were also tested as interferents but they had little detrimental effect on the ASV signals. The effect of SDS was explained by the formation of mixed micelles which scavenge the interferent in the bulk solution and by competitive displacement of the interferent at the electrode surface.     

Phase diagrams of the systems (I) Sodium dodecyl sulphate — octyl trimethyl ammonium bromide-water, (II) Sodium dodecyl sulphate — dodecyl trimethyl ammonium bromide-water

Summary Ternary phase diagrams of the pseudo three component systems sodium dodeoyl sulphate (SDS) + octyl trimethyl ammonium bromide + water (I) and SDS + dodecyl trimethyl ammonium bromide + water (II) at 298.2 K are presented. In (I) the liquid crystal region stretches continuously between the two surfactant/water axes and (for a 1∶1 surfactant ratio) penetrates very deeply into the water corner. There also appears to be a two liquid region near this corner. In (II) solid, probably 1∶1 complex, is formed over much of the diagram. An explanation of the transition between neat and middle phases at constant water content is forwarded.

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Zusammenfassung Es werden die tern?ren Phasendiagramme der Pseudodreikomponentensysteme von Natriumdodecylsulfat (NaDS) + Oktyltrimethylammoniumbromid + Wasser (I) sowie NaDS + Dodecyltrimethylammonium-bromid + Wasser (II) bei 298,2 °K dargestellt. In (I) streckt sich das kristallin-flüssige Gebiet endlos zwischen den zwei Tensid/Wasser-Achsen und (für ein Tensidverh?ltnis 1∶1) dringt sehr tief in die Wasserecke ein. In (II) wird ein fester Komplex — wahrscheinlich 1∶1 — über einen wesentlichen Teil des Diagramms gebildet. Es wird eine Erkl?rung des übergangs zwischen der reinen („neat“) und der mittleren Phase bei konstantem Wassergehalt vorgestellt.