Sulphonated Polystyrene Resins Research Articles

Epoxidation of jatropha oil using heterogeneous catalysts suitable for the Prileschajew reaction: Acidic resins and immobilized lipase

Sulphonated polystyrene resins, Nafion-silica and immobilized lipase were used as heterogeneous catalysts for the epoxidation of jatropha oil. Immobilized lipase showed ca. 100% conversion and 100% epoxide selectivity at 24 h. However, this catalyst cannot be reused because it completely deactivates after one use. For the selective epoxidation of vegetable oils with percarboxylic acids the most crucial feature to prevent the formation of glycols is to minimize the exposure of the epoxide to the acidic sites of the catalyst. This can be achieved using resins with a high level of cross-linking and with low external surface area. Activity can be increased by increasing the strength of the acid sites. Amberlite IR-120 was the best heterogeneous catalysts, yielding ca. 90% conversion and 70% epoxide selectivity, both stable through five re-uses. Dowex 50WX2 afforded the production of glycols with more than 90% selectivity at conversions of ca. 90%.

Sulphonated polystyrene resins: acidities and catalytic activities

A flow microcalorimetric technique for characterising the acidities of sulphonated polystyrene resins by ammonia adsorption from the gas phase has been applied to a series of macroporous and gel-type resin catalysts. The relationship between acidities measured using this technique and catalytic activities towards liquid phase reactions has been examined using two acid-catalysed test reactions. Results show that catalytic activities are not related in a simple way to the concentrations of acid sites measured by ammonia adsorption, but there is a useful correlation between the strengths of the acid sites measured in this way and catalytic activities of the resins. We conclude that acid site strength, based on ammonia adsorption and used alone, can be a useful indicator of activity for this type of acid catalyst.

Strong complex formation of carbohydrates with metal ions at alkaline pH studied by ligand exchange chromatography

At alkaline pH, carbohydrates are highly retained on a sulphonated polystyrene resin loaded with rare earth or uranyl metal ions. The complex formation is governed by the ionization of the carbohydrate moiety. pH and the type of metal ion were found to have a decisive influence on the complex formation. Binding of the metal ion to the cation exchanger and to different carbohydrates is described. The competitive complexation between solute and hydroxide to the metal ions is described as a ligand exchange reaction and a retention model is proposed. The ligand exchange column was used as precolumn in a coupled column separation system and the high selectivity is demonstrated by the separation of paracetamol glucuronide from a urine sample after filtration and direct injection.

Heparin-like activity of insoluble sulphonated polystyrene resins Part III: Binding of dicarboxylic amino acids

It has been demonstrated previously that polystyrene sulphonate possesses anticoagulant properties and that the binding of some amino acids could enhance the heparin-like properties of such resins. These properties depend on the surface density of the active groups, the nature and binding of the group and on the net charge borne by the polymer. In this paper, we describe the preparation of copolystyrene (sulphonate-dicarboxylic amino acid sulphamide) resins. By measuring their antithrombic-surface-activity, we demonstrate that the activity developed by each carboxyl group is at least roughly the same as the activity of one sulphonate group, except in the case of aspartic acid sulphamide resin for which a cooperative effect is shown. The anticoagulant properties of resins bearing phosphonate or mono-carboxylic amino acid sulphamides are also examined.

Heparin-like activity of insoluble sulphonated polystyrene resins: Part I: Influence of the surface density, nature and binding of substituted anionic groups

It was previously demonstrated that copolystyrene (sulphonate-amino acid sulphamide) resins possessed an anticoagulant heparin-like activity in the presence of blood plasma. Taking into account the variable surfaces of swollen resins developed by these dry resins, it is now shown that the antithrombic activity of crosslinked sulphonated polystyrene is linearly dependent on the surface density of the sulphonate groups. This fact implies that the presence of such isolated groups is sufficient to obtain a catalytic site for increasing the rate of inactivation of thrombin by plasmatic proteins. It is also shown that replacing sulphonate groups either by directly backbone-bonded carboxylate groups or by methionine linked by amide bonds to polystyrene backbone is not sufficient to endow the resulting resins with a significant anticoagulant activity.

Cross-linking of collagen. Isolation, structural characterization and glycosylation of pyridinoline.

A method for the isolation and purification of pyridinoline from bone collagen was developed, with the use of sulphonated polystyrene resins. The analytical techniques were used to quantify pyridinoline, for which hydroxyallysine is a known precursor, in a wide range of tissues. The structure of pyridinoline proposed by Fujimoto, Moriguchi, Ishida & Hayashi [(1978) Biochem. Biophys. Res. Commun. 84, 52-57] was confirmed by 13C-n.m.r. spectroscopy and fast-atom-bombardment mass spectrometry. At concentrations greater than about 0.1 mM, pyridinoline exhibited altered fluorescence properties that were consistent with excimer formation. From alkali hydrolysates of several different tissues, a fluorescent compound was purified by gel filtration and ion-exchange chromatography and was shown to be galactosylpyridinoline. This derivative was very labile to acid treatment compared with the bifunctional cross-link analogues, and was completely converted into free pyridinoline by heating at 108 degrees C for 8 h in 0.1 M-HCl. Galactosylpyridinoline was also partially converted into free pyridinoline by prolonged alkali hydrolysis. This lability, which could also apply to other multifunctional cross-link derivatives, may explain the fact that no disaccharide derivatives of pyridinoline were isolated.

Controlled Release Formulations for Phenols 1 : Use as Sex Attractant Lures for the Grass Grub Beetle 2

Controlled release of simple phenolic compounds has been achieved using sulphonated polystyrene resins. Phenols can be loaded directly onto the polymer from aqueous solution or incorporated as the potential phenol via the stabilised diazonium sulphonate. This allows the production of potent new sex attractant lures for the male grass grub beetle, Costelytra zealandica (White). These novel types of attractant formulation have a considerably longer field life than those previously available.

Distribution coefficients and cation-exchange selectives of elements with AG50W-X8 resins in perchloric acid

Cation-exchange distribution coefficients with AG50W-X8, a sulphonated polystyrene resin, aie presented for 44 cations in perchloric acid solutions of concentrations varying from 0.1 to 4.0 M. The cations are arbitrarily arranged in a table according to their distribution coefficients in 1.O M perchloric acid. Some possible separations are discussed and elution curves are presented for the separation of the ion pairs Zn-Pb, Tl(I)-Bi, Mg-Al and Co(II)-Fe(III). Selectivity sequences for uni-, bi-, ter- and quadrivalent cations are given in which the cations are ordered on the basis of the average numerical value of their distribution coefficients over the straight part of the curve obtained by plotting the logarithm of the distribution coefficient against the logarithm of [H +].

An improved system for automatic amino-acid analysis.

In a study of the characteristics of sulphonated polystyrene resin, essential to the separation of amino-acids, the cross-linkage, or water regain value, the diameters of the resin beads and the degree of sulphonation of the ion-exchange resin are shown to be important factors in the separation of individual amino-acids from their complex mixtures.

Chromatographic separation of diastereoisomeric esters—II Mandelates and lactates of 2-methylbutanol-1, 3-methylbutanol-2, pentanol-2 and hexanol-2

The racemic alcohols, 2-methylbutanol-l, 3-methylbutanol-2, pentanol-2 and hexanol-2 have been esterified with optically active mandelic or lactic acid, and the resultant mixtures of diastereoisomeric esters separated chromatographically with an optically inactive sulphonated polystyrene resin as the stationary phase and water or dilute aqueous sodium sulphate as the mobile phase. Lactate esters were more easily separated than mandelate esters. The Chromatographic separation of 26 mmole of (+/-)-3-methyl-2-butyl(+)-lactate and subsequent hydrolysis of the fractions containing only the ester of the (+)-alcohol yielded 1-2 mmole of pure 3-methyl-2-butanol.

The gradient of electrical potential difference and of sodium and potassium of the gut contents along the caecum and colon of normal and sodium‐depleted rats

1. The Na, K and water content of stools, and of gut contents removed from the terminal ileum, caecum and colon were determined in normal and Na-depleted rats and the p.d. across the colon wall measured at the site of removal of each specimen.2. During passage through the caecum and colon, especially the ascending segment of colon, the faecal Na and water content fell considerably, K content being unchanged in the normal rats and falling in the Na-depleted. Na concentration of the faecal water fell but K concentration rose owing to water absorption.3. Feeding normal rats with a sulphonated polystyrene resin caused a considerable Na loss in the stool, the ratio Na/(Na+K) being consistently greater than in rats not taking resin. Resin induced little Na but much K loss in Na-depleted rats.4. The electrical p.d. across the colon wall varied little over the length of the caecum and colon in normal rats, rarely exceeding 20 mV, the serosa being +ve with respect to lumen. Potential difference measurements were greater in Na-depleted rats, and those of the caecum and descending colon were consistently higher than those of the ascending colon. There was a similar pattern in resin-fed rats but potentials tended to be higher.5. K concentration of the gut contents was always greater than could be accounted for if K were passively distributed across the colonic mucosa.6. It was concluded that: (i) active Na absorption was stimulated by Na depletion; (ii) K was probably actively transported into the colon lumen, and when unabsorbable anions were present in the gut K secretion was critically important in Na absorption; (iii) the elevation of p.d. associated with Na depletion was probably associated with the stimulated Na transport.

Ion-exchange equilibria in the presence of organic solvents—III : Influence of organic solvents on the distribution coefficients of caesium, barium and zinc ions

The change in the distribution coefficients of caesium, barium and zinc ions on the sulphonated polystyrene resin KU-2, as a function of organic solvent concentration in hydrochloric acid solution, is studied. The organic solvents investigated are methyl alcohol, isopropyl alcohol and acetone. From the data obtained, it is possible to devise separations of zinc and caesium and of barium and caesium.

1040. The sorption of oxytetracycline and chlorotetracycline by sulphonated polystyrene resins

1040. The sorption of oxytetracycline and chlorotetracycline by sulphonated polystyrene resins

A study on the liberation of sugars, hexuronic acid, and hexosamine from biological material.

Sulphonated polystyrene resin suspended in dilute hydrochloric acid and 4 N hydrochloric acid were compared with respect to (a) efficiency as catalysts of hydrolytic cleavage of mucopolysaccharides and (b) rates of destruction of sugars, glucuronic acid, and glucosamine. Mannose, galactose, and glucose were not subject to serious destruction when heated with the resin suspension over a period that was sufficient to effect hydrolysis of mucopolysaccharides and glycoproteins. All these sugars were subject to serious destruction when heated with 4 N hydrochloric acid for a period sufficient to effect hydrolysis of mucopolysaccharides and glycoproteins. Under similar conditions, pentoses were destroyed more rapidly than hexoses but ribose withstood heating with the resin suspension for several hours. Heparin was found to be more resistant to hydrolysis than chondroitin sulphate or hyaluronic acid.

Separation of amino-acid mixtures on sulphonated polystyrene resin-loaded papers.

THE high resolving powers of columns of cross-linked sulphonated polystyrene resins when applied to the separation of mixtures of amino-acids has been demonstrated by the classic work of Moore and Stein1 and afterwards by other workers2,3.

Behaviour of Some Aldehydes on a Sulphonated Polystyrene Resin

5-HYDROXYMETHYL 2-FURALDEHYDE is a Well-known product from the browning reaction1 between certain sugars and amino-compounds. In the course of its isolation from such a reaction mixture it was assumed that it would be easily eluted, together with the unreacted sugar present, from a column of ‘Zeokarb 225 [H+]’ resin. Instead it was found that the volume of 0.3 N hydrochloric acid required to elute it was approximately 0.6 of that required to elute D-glucosamine. Passage of 2-furaldehyde and salicylaldehyde down the same column (Fig. 1) revealed that these were even more strongly absorbed. Since 5-hydroxymethyl 2-furaldehyde showed no evidence of behaving as a base on paper ionophoresis in either 0.75 M formate buffer pH 2 or 0.3 N hydrochloric acid, the explanation for its retention must lie in some other mechanism of interaction with this sulphonated polystyrene resin.

LIBERATION OF HEXOSAMINE, HEXURONIC ACID, AND HYDROXYPROLINE FROM TISSUES BY RESIN HYDROLYSIS

Excess sulphonated polystyrene resin (Dowex-50, 200–400 mesh) suspended in 0.05 N hydrochloric acid has been found suitable as a catalyst for the hydrolysis of tissue samples preparatory to the determination of hexosamine, hexuronic acid, and hydroxyproline. This technique protected hexuronic acid from destruction during hydrolysis sufficiently well to permit of its determination. The resin used in hydrolysis has been used also for separation of sugars and hexuronic acid from hexosamine and hydroxyproline by differential elution.

LIBERATION OF HEXOSAMINE, HEXURONIC ACID, AND HYDROXYPROLINE FROM TISSUES BY RESIN HYDROLYSIS

Excess sulphonated polystyrene resin (Dowex-50, 200–400 mesh) suspended in 0.05 N hydrochloric acid has been found suitable as a catalyst for the hydrolysis of tissue samples preparatory to the determination of hexosamine, hexuronic acid, and hydroxyproline. This technique protected hexuronic acid from destruction during hydrolysis sufficiently well to permit of its determination. The resin used in hydrolysis has been used also for separation of sugars and hexuronic acid from hexosamine and hydroxyproline by differential elution.

An ion exchange method of determining carnosine, anserine and their precursors in animal tissue.

ALTHOUGH elegant procedures have been described for the separation of the neutral and acidic amino-acids by elution from sulphonated polystyrene resins, the quantitative separation of the basic amino-acids has proved more difficult1,2. For example, when the pH of the eluting buffer is more than 7 their recoveries rarely exceed 80 per cent. It is for this reason that buffers of pH less than 7 and relatively high sodium ion concentration have previously been used in their separation, although such conditions greatly reduce the sensitivity of the method.

Properties of ion-exchange resins in relation to their structure. Part VII. Cation-exchange equilibria on sulphonated polystyrene resins of varying degrees of cross-linking

Properties of ion-exchange resins in relation to their structure. Part VII. Cation-exchange equilibria on sulphonated polystyrene resins of varying degrees of cross-linking