Sulfonated Styrene-divinylbenzene Copolymer Research Articles

Reaction of Partially Methylated Polygalacturonic Acid with Iron(III) Chloride and Characterization of a New Mixed Chloride-Polygalacturonate Complex.

We have described a new route for the preparation of partially methylated polygalacturonic acid containing hydrolyzed (acidic) and unhydrolyzed (methyl esterified) carboxylate groups in a ratio of 1:1 (PGA, compound 1), and one of its basic FeIII-salts (compound 2) with a ~1:2 FeIII:GA stoichiometry (GA means galacturonic acid and methylated galacturonic acid units). The partially hydrolyzed pectin was transformed into compound 1 with the use of double ion exchange with a strongly acidic macroreticular sulfonated styrene-divinylbenzene copolymer as a hydrogen ion source. The reaction of compound 1 with FeCl3 resulted in compound 2. Compound 2 has a polymeric nature and contains binuclear FeIII(µ-O)(µ-OH)FeIII core units with two kinds of distorted octahedral iron geometries. The salt-forming acidic and methylated GA units of compound 1 are coordinated to FeIII centers in asymmetric bidentate-chelating and -bridging (via C=O group and glycosidic oxygen) modes, respectively. Two kinds of outer-sphere chloride anions were also detected by XPS in various chemical environments fixed by different sets of hydrogen bonds. We also observed a partial reduction of FeIII into FeII due to the ring-opening of the chain-end GA units of compound 1. This reaction provides a new route to determine the number of chain-ends in compound 2, and with the use of the number of GA units calculated from charge neutrality, the average length of these chains and the average molecular weight were also determined. The average molecular weight of the partially methylated polygalacturonic acid used in the industrial-scale production of commercial anti-anemic iron-polygalacturonate agents was ~50,000 g/mol. Compound 2 was also characterized by IR, Mössbauer, and X-ray photoelectron spectroscopy, and magnetic susceptibility measurements. These results on the structure and average molecular weight of basic iron(III) polygalacturonate provide a tool to design Fe-PGA complexes with tuned iron-releasing properties.

СИНТЕЗ ТА АНТИБАКТЕРІАЛЬНІ ВЛАСТИВОСТІ 4-АМІНОФЕНІЛСУЛЬФОНАМІДУ, ІММОБІЛІЗОВАНОГО НА ПОЛІМЕРНОМУ НОСІЇ

Мета роботи. У сучасних умовах іммобілізація лікарських засобів на полімерних носіях набуває все більшого значення, що пов’язане з вимогами до зменшення токсичності та пролонгації дії препаратів. Відома іммобілізація сульфаніламідних препаратів на стиромалі, метакрилатних полімерних матрицях, де фармакологічно активний сульфаніламід легко вивільняється з полімеру при застосуванні, в результаті кислотного гідролізу. Разом з тим спостерігається, що іммобілізовані сульфаніламіди, отримані на основі амінометильованого співполімеру стиролу з дивінілбензолом, незважаючи на стійкість до гідролізу, зберігають антибактеріальні властивості. З метою розширення прикладів ковалентної іммобілізації сульфаніламідів нами синтезовані 4-амінофенілсульфонаміди на гранульній і волокнистій формах співполімерів стиролу з дивінілбензолом через місткову групу SO2.Матеріали і методи. Як вихідну сировину використано макропористий гранульний співполімер стиролу з дивінілбензолом і сульфовані волокнисті форми прищепленого до поліпропіленової нитки співполімеру стиролу з дивінілбензолом. Сульфохлоруванням цих співполімерів отримано полімерні сульфохлориди, які використовували в реакції з 4-амінофенілсульфонамідом. Антибактеріальні властивості матеріалу досліджені за визначенням зон пригнічення росту тест-мікроорганізмів E.coli К-12 на поживному середовищі.Результати й обговорення. Будову синтезованих іммобілізованих 4-амінофенілсульфонамідів доведено методом ІЧ спектроскопії. Показано, що такі матеріали проявляють виражені антибактеріальні властивості щодо тест-культури мікроорганізмів E. coli К-12, незважаючи на їхню стійкість до гідролізу.Висновки. Зроблено припущення, що гідроліз матеріалів перебігає при специфічному ферментативному каталізі на поживному середовищі виділенням 4-амінофенілсульфонаміду.

X-Ray absorption fine structure spectroscopy studies of thermal effects on ion-exchange equilibria

The effect of temperature on the first-shell coordination structures for Rb+, Sr2+, Br−, and I− in aqueous solution and those for Rb+ and Sr2+ in a sulfonated styrene-divinylbenzene copolymer cation-exchange resin have been evaluated by X-ray absorption fine structure (XAFS) spectroscopy in order to elucidate the origin of the effect of temperature on ion-exchange equilibria. XAFS measurements on aqueous solutions containing the inorganic ions in the temperature range from ambient temperature to 175 °C at 3 MPa indicate that the number of coordinated first shell water molecules decreases with an increase in temperature, while the first shell ion–oxygen (water) bond length remains almost unchanged (Sr2+ and I−) or slightly decreases (Rb+ and Br−). The spectral changes observed for Rb+ and Sr2+ in the hydrated cation-exchange resin were nearly the same as those for the ions in aqueous solution, though there is an indication for the contact ion pairs with the fixed sulfonate groups at high temperatures. These data represent the direct spectroscopic confirmation of structural change around inorganic ions in an ion-exchange resin as well as in aqueous solutions. The effect of temperature on separation selectivity in ion-exchange processes can be interpreted by the change in hydration of ions clarified in the present study.

Heterogeneous ion-selective membranes: the influence of the inert matrix polymer on the membrane properties

Heterogeneous ion-exchange membranes were prepared by mixing small particles of sulfonated poly(1,4-phenylene sulfide) or sulfonated styrene–divinylbenzene copolymer with a matrix polymer. Four kinds of polymers were tested as a matrix: highly flexible linear polyethylene, medium-flexible fluoroelastomer, rigid polystyrene (all highly hydrophobic) and hydrophilic cellulose prepared by hydrolysis of cellulose acetate butyrate. Membrane morphologies were studied by scanning electron microscopy, IR spectroscopy and density measurements. Subsequently, the membranes were characterised with respect to their swelling in water, electrochemical characteristics and transport properties. Ion-exchange capacity and proton conductivity together with the permeability to hydrogen and methanol were investigated. The important impact of the ion-exchange particles as well as of the polymer matrix used was observed. The increasing rigidity of the polymer matrix resulted in a decrease in membrane permeability, but at the same time in deterioration of its ion-exchange capacity and subsequently of the proton conductivity, too. This was explained in terms of the limited elasticity of the polymer matrix, in each sample under study, which does not allow the ion-exchange particles to swell to an identical degree.

In situ synthesis of iron oxide nanoparticles in a styrene-divinylbenzene copolymer

Magnetic iron oxide nanoparticles were prepared by in situ within a sulfonated styrene-divinylbenzene copolymer. The magnetic nanocomposite was characterized by X-ray diffraction, transmission electron microscopy and vibrating sample magnetometry. The size distribution of the nanoparticles was relatively narrow with good distribution within the copolymer. Nearly spherical nanoparticles, 7 nm in diameter, were identified as CoFe2O4 and had a well-defined crystalline structure. Magnetic measurements revealed that the magnetic nanocomposites are superparamagnetic.

Determination of the adsorption model of alkenes and alcohols on sulfonic copolymer by inverse gas chromatography

The determination of a number of adsorption sites on sulfonated styrene–divinylbenzene copolymer for alkenes (propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, isobutene, 2-methyl-1-butene, 2-methyl-2-butene, 2-methyl-1-pentene, 2-methyl-2-pentene and 2-methyl-2-hexene) and alcohols (methanol, ethanol and n-propanol, n-butanol, 2-butanol and tert-butanol) was performed by the saturation copolymer with vapors of adsorbate, by removing the excess of adsorbate from copolymer by blowing the inert gas through copolymer bed and by the desorption of adsorbed alcohol in the programmed increase of temperature. The adsorption measurements were performed on sulfonated ion-exchange resin (Amberlyst 15) with different concentrations of the acid group, which means with a varying number of adsorption sites. The following adsorption models for alkenes were suggested: the first in which one molecule of alkene is adsorbed by two sulfonic groups, for linear alcohols, the second in which one sulfonic group can adsorb one molecule of alcohol and for non-linear alcohols the third where one molecule of alcohol is adsorbed by two or more sulfonic groups.

Ion-exclusion chromatographic separations of C 1–C 6 aliphatic carboxylic acids on a sulfonated styrene–divinylbenzene co-polymer resin column with 5-methylhexanoic acid as eluent

The application of C 7 aliphatic carboxylic acids (heptanoic, 2-methylhexanoic, 5-methylhexanoic and 2,2-dimethyl- n-valeric acids) as eluents in ion-exclusion chromatography with conductimetric detection for C 1–C 6 aliphatic carboxylic acids (formic, acetic, propionic, isobutyric, butyric, isovaleric, valeric, isocaproic and caproic acids) was carried out using a highly sulfonated styrene–divinylbenzene co-polymer resin (TSKgel SCX) in the H + form as a stationary phase. When using 0.05 m M sulfuric acid at pH 4.0 as the eluent, peak shapes of hydrophobic carboxylic acids (isovaleric, valeric, isocaproic and caproic acids) were tailed strongly. In contrast, when using 1 m M these C 7 carboxylic acids at pH ca. 4 as the eluents, although system peaks (vacant peaks) corresponding to these C 7 carboxylic acids appeared, peak shapes of these hydrophobic acids were improved drastically. Excellent simultaneous separation and relatively high sensitive conductimetric detection for these C 1–C 6 aliphatic carboxylic acids were achieved in 25 min on the TSKgel SCX column (150×6 mm I.D.) using 1 m M 5-methylhexanoic acid at pH 4.0 as the eluent.

Separation of C 1–C 5 aliphatic carboxylic acids on a highly sulfonated styrene–divinylbenzene copolymer resin column with a C 6 aliphatic carboxylic acid solution as the mobile phase

Simultaneous separation of C 1–C 5 aliphatic carboxylic acids (formic, acetic, propionic, iso-butyric, butyric, iso-valeric and valeric acids) on a highly sulfonated styrene–divinylbenzene copolymer resin column (TSKgel SCX, 150 mm×6 mm i.d.) was performed with C 6 aliphatic carboxylic acids (3-methyl- n-valeric, iso-caproic and caproic acids) solutions as the mobile phases. Using 0.05 mM sulfuric acid at pH 4.0 as the mobile phase, although good separation of these C 1–C 5 acids was achieved, peaks of the C 5 acids ( iso-valeric and valeric acids) with large hydrophobicity tailed strongly. In contrast, using 1 mM C 6 acids at pH ca. 4.0 as the mobile phases, although vacant peaks corresponding to the C 6 acids in the mobile phase appeared, the peak shapes of the C 5 acids were improved greatly. Excellent simultaneous separation, symmetrical peaks and relatively high-sensitivity conductimetric detection for these C 1–C 5 acids were achieved on the TSKgel SCX column in 15 min with 1 mM iso-caproic acid at pH 4.0 as the mobile phase.

Ion-exclusion chromatographic behavior of aliphatic carboxylic acids and benzenecarboxylic acids on a sulfonated styrene–divinylbenzene co-polymer resin column with sulfuric acid containing various alcohols as eluent

The addition of C 1–C 7 alcohols (methanol, ethanol, propanol, butanol, heptanol, hexanol and heptanol) to dilute sulfuric acid as eluent in ion-exclusion chromatography using a highly sulfonated styrene–divinylbenzene co-polymer resin (TSKgel SCX) in the H + form as the stationary phase was carried out for the simultaneous separations of both (a) C 1–C 7 aliphatic carboxylic acids (formic, acetic, propionic, isobutyric, butyric, isovaleric, valeric, 2-methylvaleric, isocaproic, caproic, 2,2-dimethyl- n-valeric, 2-methylhexanoic, 5-methylhexanoic and heptanoic acids) and (b) benzenecarboxylic acids (pyromellitic, hemimellitic, trimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic and salicylic acids and phenol). Heptanol was the most effective modifier in ion-exclusion chromatography for the improvement of peak shapes and a reduction in retention volumes for higher aliphatic carboxylic acids and benzenecarboxylic acids. Excellent simultaneous separation and relatively highly sensitive conductimetric detection for these C 1–C 7 aliphatic carboxylic acids were achieved on the TSKgel SCX column (150×6 mm I.D.) in 30 min using 0.5 m M sulfuric acid containing 0.025% heptanol as eluent. Excellent simultaneous separation and highly sensitive UV detection at 200 nm for these benzenecarboxylic acids were also achieved on the TSKgel SCX column in 30 min using 5 m M sulfuric acid containing 0.075% heptanol as eluent.

Electron Microscopy Investigation of Magnetite Nanoparticles Immersed in a Polymer Template

Transmission electron microscopy and scanning electron microscopy were used to investigate chemically cycled magnetite-based composites using mesoporous sulfonated styrene-divinylbenzene copolymer as template. The micron-sized morphology of the template was investigated using scanning electron microscopy, while transmission electron microscopy provided useful information concerning the nanoparticle size polydispersity profile and location of the magnetite nanoparticles inside the template. The narrowing of the nanoparticle size distribution and the linear dependence of the magnetite mass incorporation versus number of chemical cycles are supported by the transmission electron microscopy data.

High-performance liquid chromatographic assay of (±)-lactic acid and its enantiomers in calf serum

Two high-performance liquid chromatographic methods are described for the determination of lactic acid and its enantiomers in calf serum. A 300×8.0 mm I.D. column packed with sulfonated styrene–divinylbenzene copolymer and a 50×4.6 mm ODS column with N, N-dioctyl- l-alanine were used. UV detection was at 205 and 236 nm for the non-chiral and chiral assays, respectively. Both assays demonstrated excellent linear relationships between peak area ratios and serum concentrations over a range of 0.5 to 20 m M, based on 100 μl bovine serum. Recovery was complete. Inter- and within-batch bias and relative standard deviation were <15%.

High-performance liquid chromatographic identification of eight constitutional disaccharides from heparan sulfate isomers digested with heparitinases.

Identification with specific heparan sulfate-lyases, heparitinase I and heparinase of the constitutional unsaturated disaccharide (delta Di-SHS) derived from heparan sulfate (HS) isomers and heparin was achieved using high-performance liquid chromatography (HPLC) with a sulfonated styrene-divinylbenzene copolymer. Eight delta Di-SHS products derived from HS isomers were identified. Enzymatic digestion with heparitinase I and heparinase converts heterogeneous sulfated HS isomers and heparin into different delta Di-SHS. The practical application of these enzymes was examined using specific enzymes and HPLC. In a patient with Hurler syndrome, eight individual delta i-SHS were identified in urinary HS isomers.

Transport Properties of Cation-Exchange Membrane–Aqueous Electrolyte System

Abstract Transport properties of a cation-exchange membrane-aqueous sodium chloride solution system have been studied. The membrane used was a sulfonated styrene–divinyl benzene copolymer, Neosepta C66-5T. The salt concentration was kept at 10−1 mol dm−3 on one side of the membrane and varied from 10−3 to 10−2 mol dm−3 on the other. The six elements of a conductance matrix have been experimentally determined according to the previous theory and the membrane properties were discussed in terms of conductance elements. All the elements of the conductance matrix were positive within the concentration range studied. This would be characteristic of a cation-exchange membrane. The electrical ion conductance was greater than the diffusional ion conductance by a factor of 10 to 100. The ion-solvent coupling coefficient was much less than the interionic one, although the electroosmotic conductance was ten-times greater than the membrane conductance. The reflection coefficient was close to unity. The electroosmotic properties were also discussed in terms of the conductance matrix.

N-(ϱ-coumaryl)-tryptamine and N-ferulyl tryptamine in kernels of Zea mays

N-(ϱ-coumaryl)tryptamine and N-ferulyltryptamine were isolated from aqueous acetone extracts of ground kernels of Zea mays by successive column chromatography on partially sulfonated styrenedivinylbenzene copolymer resin, lipophilic Sephadex and preparative TLC. Identification of these compounds was made by GCMS of their trimethylsilyl derivatives and the trimethylsilyl derivatives of their acid hydrolysis products.

The dehydration of methanol and ethanol catalyzed by polystyrene sulfonate resins

Initial rates of the reaction of methanol and of ethanol to give water and the corresponding ether were obtained utilizing a packed-bed flow reactor. The reactions were conducted isothermally at 1 atm total pressure, as vapor-phase reactants contacted catalyst at temperatures from 80 ° to 120 °C. The catalyst was a sulfonated styrene-divinylbenzene copolymer (Dowex 50). The hydrogen form resin was altered by successively replacing hydrogen exchange ions with lithium ions in one series, and with sodium ions in another series. Reaction rate depression became complete at complete replacement of hydrogen ions. Lithium-containing catalysts were more active than sodium-containing catalysts of the same hydrogen content. A bimolecular rate-determining reaction step is indicated, with hydrogen ions being required for catalyst activity. A structure is proposed for the reaction intermediate.