Polyethylene/poly(styrene-co-divinylbenzene) sodium sulphonate membranes : Part 1. Synthesis and properties

Transport properties of cation-exchange membranes have been studied. The self-diffusion coefficients of sodium and chloride ions, the transport numbers of sodium ions and water, and the conductivities were measured in 0.1 M sodium chloride at 25°C. The concentration potentials were determined in the system 0.05/0.15 M sodium chloride.The membranes were prepared by sulphonation of oriented polyethylene (PE) film modified with 30 wt % of styrene—divinylbenzene copolymer (poly(St-co-DVB)). The copolymer was introduced by interpolymerization of the monomers within the film without its dissolution. A sequence of membranes having similar ion-exchange capacity but differing in water content was then obtained from sheets of normal PE/poly(St-co-DVB)SO₃Na membranes by expanding them by heating in water followed by a thermal treatment in air.The deviations of the measured transport properties from the behaviour of homogeneous membranes and the analysis of the Kedem—Katchalsky relationships for composite membranes have led to the conclusion that in PE/poly(St-co-DVB)SO₃Na membranes a structure prevails with a series arrangement of layers with different properties.     

Binding studies of sodium dodecyl benzene sulphonate with poly(N-vinyl-2-pyrrolidone)

The binding of sodium dodecyl benzene sulphonate (SDBS) with poly(N-vinyl-2-pyrrolidone) (PVP) has been investigated at 303.15 and 313.15 K using equilibrium dialysis, surface tension, viscosity, ultrasound velocity and ultrasound absorption techniques. From each of these studies four distinct regions of SDBS-PVP interactions were observed. Interaction of SDBS with PVP was found to involve the binding of surfactant dimers with the polymer molecule followed by usual micellization. The binding data has been analyzed in terms of various models of polymer-surfactant interaction.     

Chemiluminescence determination of sodium 2-mercaptoethane sulfonate by flow injection analysis using cerium(IV) sensitized by quinine

A flow injection method with chemiluminescence (CL) detection is proposed for the determination of sodium 2-mercaptoethane sulfonate (MESNA), a drug often used to reduce the urotoxic effects of antineoplastic alkylating agents. The procedure is based on the reaction of the thiol with Ce(IV) in a sulfuric acid medium and measurement of the CL intensity produced by quinine used as a sensitizer. The optimum conditions for CL emission were investigated. Using the CL peak height as the analytical parameter, MESNA was determined over the concentration range 0.29–2.21 ng (1.97–9.85 μg·l⁻¹) with a detection limit of 0.21 ng (1.38 μg·l⁻¹) and a relative standard deviation (R.S.D.) of 4.1%. The method was applied satisfactorily to the determination of MESNA in pharmaceutical preparations with percentages of recovery between 94 and 105.     

N,N-二(2-羟乙基)-2-氨基乙磺酸钠的合成研究

采用二乙醇胺与2-氯乙基磺酸钠反应合成N,N-二(2-羟乙基)-2-氨基乙磺酸钠(BES钠盐),由核磁氢谱(1H NMR)和碳谱(13C NMR)、红外光谱(FT-IR)、X射线衍射(XRD)等仪器表征了合成产物的结构和特性.根据反应体系pH值的变化及核磁谱图,确定了BES钠盐的最佳合成工艺:反应物料比为1:1:1,反...     

Integral physicochemical properties of reverse micelles of sodium bis(2-ethylhexyl) sulfosuccinate (AOT)

The effect the degree of hydration has on optical and electrophysical properties of water/AOT/n-hexane system is studied. It is found that AOT reverse micelles form aggregates whose dimensions grow along with the degree of hydration and temperature. Aggregation enhances their electrical conductivity and shifts the UV spectrum of AOT reverse emulsions to the red region. Four states of water are found in the structure of AOT reverse micelles.     

自动电位滴定法测定磺酸盐合成及产品中硫酸钠

石油系磺酸盐合成及产品 (如凝土外加剂 )中硫酸盐的测定 ,对控制磺酸盐质量具有重要意义。目前 ,磺酸盐产品中硫酸盐测定多采用“混凝土外加剂匀质性试验方法”中硫酸钡重量法或离子交换重量法[1 ] ,此法手续繁琐 ,尤其是费时 ,周期约 48ｈ ,难以满足生产特别是工艺开发阶段条件试验时调整工艺参数的要求。用铅离子作滴定剂 ,铅离子选择性电极为指示电极 ,电位滴定法测定硫酸盐是一种比较可靠的方法 ;用于磺酸盐中硫酸盐的分析 ,目前尚未见报道。作者运用计算机控制的自动电位滴定法[2 ] ,选择了适合在磺酸盐中进行测定的滴定介质、酸度、…     

The influence of sodium ethene sulphonate comonomer on the film formation process of poly(vinyl acetate) dispersions

Various latex dispersions from vinyl acetate/sodium ethene sulphonate (sodium vinyl sulphonate) copolymers, stabilised by a constant amount of Hostapal BV, a surfactant with poly(ethylene oxide) groups, were investigated by a variety of solid and liquid state nuclear magnetic resonance methods. In order to investigate the influence of sodium ethene sulphonate on the film formation process, the serum and polymer were analysed separately. The stoichiometric monomer composition of the copolymer in the aqueous phase and in the hydrophobic particles was obtained. The ionic comonomer is enriched at the particle surface via its proximity to the applied surfactant by two-dimensional exchange NMR. For investigations of the film formation process, latex dispersions were prepared and dried to form spatially homogeneous films at different defined solid contents. Depending on the chemical composition of a chosen dispersion, NMR allows the investigation of the drying process of the water. The drying process is a function of the ionic strength of the dispersion and the hydrophilicity of the polymer. It is correlated to the drying mechanism of the water within the film. A not fully dried film contains external water outside the particles, water at ionic and non-ionic groups at surfactants in the polymer water interface and, additionally, water in the swollen and mobilised polymer. The distribution of water to these environments is markedly changed by the ionic comonomer, especially close to the end of the drying process.     

Phase behavior and solution properties of sodium (3-dodecanoyloxy-2-hydroxy-propyl) succinate in water

Sodium (3-dodecanoyloxy-2-hydroxy-propyl) succinate (SLGMS) is a conjugated anionic surfactant in which a glycerol residue connects with a hydrophilic sodium succinate and dodecanoate. Aqueous micellar phase (W_m), hexagonal (H₁), bicontinuous cubic (V₁), and lamellar (L_α) phases are successively formed with increasing the surfactant concentration in a binary SLGMS-water system. The Krafft point is below 0 °C. The effective cross sectional area per surfactant molecule, a _s, in the H₁ phase is almost constant, 0.5 nm², and the shape of cylindrical micelle is almost unchanged with surfactant concentration. The cmc value of SLGMS measured by means of surface tension, electrical conductivity, and fluorescence probe methods is in the range of 4∼9 × 10⁻⁵ mol/l that is much lower than that of sodium dodecanoate, 2 × 10⁻² mol/l, or SDS, 8 × 10⁻³ mol/l. Hence, it is considered that the polar glycerol part in the SLGMS acts as a hydrophobic part. The solubilization of oil in the SLGMS solution is much higher than that in the SDS solution and this also suggests that the glycerol and succinic units act as lipophilic moieties. Received: 15 June 2000/Accepted: 27 July 2000     

High performance liquid chromatography analysis of MESNA (2-mercaptoethane sulfonate) in biological samples using fluorescence detection

MESNA is the sodium salt of 2-mercaptoethane sulfonate, a thiol-containing drug. It is an antioxidant used particularly in renal protection. Several studies have proved that MESNA has beneficial effects in ischemic acute renal failure where it scavenges reactive oxygen species (ROS), due to the presence of the thiol group. It also reduces the size of urinary bladder cancer. MESNA was proved to be effective in preventing hemorrhagic cystitis induced by high doses of several chemotherapeutic regimens such as cyclophosphamide and ifosfamide. It has been shown that MESNA functions as an uroprotective substance in drug-induced experimental bladder cancer models. Moreover, recent studies have suggested that it is also effective in reducing intestinal inflammation in colitis. Because of the increased level of interest in using MESNA for treating various disorders, a new and sensitive method was needed to understand the pharmacokinetics of this drug. Accordingly, we developed a new method for determining free MESNA in biological samples by using ThioGlo-3 [3H-Naphto [2,1-b] pyran, 9-acetoxy-2-(4-(2,5-dihydro-2, 5-dioxo-1H-pyrrol-1-yl) phenyl-3-oxo)] as the derivatizing agent. MESNA was detected fluorimetrically by reverse-phase HPLC using acetonitrile:water (75:25) along with acetic acid and phosphoric acid (1 mL/L each) as the mobile phase. The detection limit was 1.64 nm per 20 microL injection volume, with a linearity (r = 0.999) in the calibration curve extending over a range 2.5-2500 nm. The coefficients of variation for within-run and between-run precision were 0.43 and 3.31%, respectively. The relative recoveries in the biological samples were in the range 87 +/- 6 to 93 +/- 2.4%. The concentrations of MESNA in the biological samples (lungs, liver, kidney and brain) were determined. The highest concentration of MESNA was found in plasma. Of all the tissues, the kidney was found to have the highest concentration while the liver had the lowest concentration.     

Infinite-dilution viscoelastic properties of sodium poly(styrene sulfonate)

The storage and loss shear moduli G′ and G″ of dilute solutions of two samples of sodium poly(styrene sulfonate) with molecular weights (M) of 3.28 × 10⁵ have been measured. The Birnboim–Schrag multiple-lumped resonator technique was used in the frequency range 100–8000 Hz, and the intrinsic moduli were obtained by extrapolation to infinite dilution. Measurements were performed over the temperature range from 1.0 to 25.0°C in aqueous solvents containing from 0 to 60% by weight glycerol and from 0.001 to 0.005M added salt. The large intrinsic viscosities indicated high extension of the polymer, and the frequency dependences of G′ and G″ were matched well by hybrid relaxation spectra combining rodlike and coil-like behavior. In a solvent containing 0.001M sodium ion and no glycerol, the end-over-end rotational relaxation times for the two molecular weights corresponded to proportionality to the 1.7 power of M. With increasing molecular weight, ionic strength, and/or glycerol concentration, the polyelectrolyte appeared to become less extended, and its behavior more nearly coil-like.     

Vitrification and water induced crystallization of zinc(II) dodecylbenzene sulphonate

Crystallization of zinc(II) dodecyl benzene sulphonate has been suppressed by either the removal of water of hydration or the rapid cooling of the compound from the liquid crystalline state. The anisotropic structure is preserved in the solid state when the hydrated compound in the LC phase is rapidly quenched, while removal of the water of hydration at temperatures in or above the LC phase and the subsequent slow cooling produces a stable isotropic structure.     

Dynamic surface properties of sodium N-acryloyl-11-amimoundecanoate and poly(sodium N-acryloyl-11-aminoundecanoate)

Adsorption layers of sodium N-acryloyl-11-amimoundecanoate and poly(sodium N-acryloyl-11-aminoundecanoate) (PAAU-Na) are studied using surface dilatational rheology measurements. It is established that the dynamic surface elasticity values of the studied systems are different, while their surface tension isotherms are almost the same. PAAU-Na solutions containing excess indifferent electrolyte (NaCl) exhibit a conformational transition in a surface layer due to the formation of loops and tails, which penetrate the bulk phase. Slow variations in the surface properties of PAAU-Na solutions with time seem to be caused by the aggregation of macromolecules in the bulk phase. The aggregation process is investigated by scanning probe microscopy.     

Ideal nonideality in adsorption of 2-aminoethanethiol and 2-mercaptoethane sulfonic acid to form electrostatically stabilized binary self-assembled monolayers on Au(111)

In formation of binary self-assembled monolayers (SAMs) composed of 2-aminoethanethiol (AET) and 2-mercaptoethane sulfonic acid (MES) by adsorption from an ethanol solution on Au(111), the adsorption shows nearly ideal nonideality in that the surface ratio of MES to AET in the SAM is unity and does not depend on the mixing ratio of MES to AET in the bathing ethanol solution used for preparing SAMs, chi(soln)MES, over the wide range of chi(soln)MES between 0.01 and 0.95. X-ray photoelectron spectroscopy confirms that at least 80% of AET molecules adsorbed are protonated in this range of chi(soln)MES, indicating that the electrostatic interaction between positively charged AET and negatively charged MES is responsible to the observed nonideality. Correspondingly, there appears only one cathodic peak in a linear-sweep voltammogram of the reductive desorption of the SAM, having a narrow full width at half-maximum of about 20 mV. This suggests the presence of strong lateral attractive interaction between the adsorbed thiolates.     

Determination of Na(2)O from sodium aluminate NaAlO(2)

The aim of the work was to find a suitable method and conditions for determining Na(2)O wt.% from NaAlO(2). Problems were encountered while titrating NaAlO(2) with hydrochloric acid. The problematic area was the pH range 4-10 where aluminum precipitates as hydroxides. The different species of the aluminate solution were determined using potentiometric and complexometric titrations. The equivalent point of the potentiometric titration was detected using Gran's plotting method. Precipitation of aluminum hydroxides did not interfere with titrations, because in potentiometric titrations the pH value was over 10 and in complexometric titrations the pH was 4. The results were accurate and determinations were easy to carry out. Sodium was also determined by DCP-AES.     

Liquid crystal and solution phases of sodium dodecyl-p-benzene sulphonate (NaLAS) and octa-oxyethylene glycol hexadecyl ether (C16E8): 1:1 mixtures in water

The liquid crystals and other phases formed when the mixed surfactant system sodium dodecyl-p-benzene sulphonate (NaLAS) and octa-oxyethylene glycol hexadecyl ether (C₁₆E₈, 1:1 by weight) is dispersed in water have been investigated using optical microscopy, X-ray diffraction and differential scanning calorimetry. Despite the fact that neat LAS is a multi-phase solid and C₁₆E₈ is a crystalline solid, when the two are mixed at temperatures above the melting temperature of the C₁₆E₈ with no water present, what appears to be a metastable gel phase formed containing only a small volume fraction of un-dissolved LAS (ca. 5%). Moreover, when water is added to the system, the phase behaviour of the mixture considerably differs to that of either of the individual components. We report a detailed phase study on this mixture here particularly focussing on the ‘neat’ mixture. The phase behaviour when water is added is also discussed. Particularly interesting is the presence of a micellar phase between the hexagonal and lamellar phases thought to be due to weak interactions between micelles during the transition from rods to discs. In addition, the presence of a low temperature intermediate phase is discussed.     

Synthesis,structure, and luminescence properties of sodium and ytterbium complexes with 2-(benzothiazol-2-yl)selenophenolate ligands

Russian Chemical Bulletin - With the aim of designing new heteroorganic ligands capable of sensitizing the metal-centered photoluminescence (PL) of YbIII through the redox mechanism, a new...