Naotake Ogawa

Preparation and properties of macroreticular resins containing thiazole and thiazoline groups

Three macroreticular polystyrene-based resins with amino- or imino-thiazole and thiazoline groups as the functional groups have been prepared. The resins are highly stable in acid and alkaline solutions and have high selectivity for mercury(II). In the presence of hydrochloric acid, sorption of mercury attains equilibrium fairly rapidly, the time for 50% uptake of mercury being 3-6 min. There are practically no interferences. In a column operation, mercury is quantitatively recovered by elution with 0.1M hydrochloric acid containing 5% thiourea. The thiazoline resin column can be used to concentrate mercury from sea-water.

Synthesis and properties of a new chelating resin containing the oxime group

A macroreticular polystyrene-based chelating resin with oxime and diethylamino functional groups has been synthesized. The resin is stable in acid and alkaline solutions; no decrease in nitrogen content or capacity for sorption of copper(II) is observed when it is exposed to 3M hydrochloric acid and 1M sodium hydroxide for 7 days. The resin has higher selectivity for copper(II) than for other metal ions tested and the time required for 50% uptake of copper(II) is 15 min. The highest capacity for copper(II) is 2.0 mmole/g at pH 6.0. In a column operation, quantitative recovery of copper(II) is achieved by elution with 1M hydrochloric acid, and the resin can be used repeatedly.

Selective metal sorption on cross-linked poly(vinylpyridine) resins

The sorption behaviour of several metal ions on five kinds of poly(4- or 2-vinylpyridine) resins, cross-linked with divinylbenzene, and with different surface properties, are examined. All the resins proposed sorb some metal ions effectively in a similar manner by anion-exchange, while the sorption of metal ions by complex formation with the pyridine moiety is strongly affected by the surface properties of the resins. A macroreticular poly(4-vinylpyridine) resin shows high affinity for copper and nickel ions in acetate buffer. Sodium chloride and/or methanol added to the working solutions influence the sorption capacities for metal ions. This resin was applied to the separation of copper/cobalt and nickel/cobalt and the concentration of copper from sea-water by a column operation.

Synthesis and properties of a chelating resin containing triazolethiol groups.

A macroreticular poly(acrylic acid)-based resin with triazolethiol as the functional group has been synthesized. The stability of the resin in acidic media and the behaviour in sorption and desorption of various metal ions have been investigated and compared with those of the acylthiosemicarbazide resin which is an intermediate in synthesis of the triazolethiol resin. Both resins show high affinity for copper(II) silver, cadmium and mercury(II), and high selectivity for silver and mercury(II) at low pH (1-2), and even at pH 7 if EDTA is present. The triazolethiol resin sorbs metal ions faster than the acylthiosemicarbazide resin does and sorbs mercury(II) from high concentrations of acids and neutral salt solutions. This resin has been applied to the concentration of silver and mercury(II) from sea-water samples by column operation.

Liquid chromatographic characterization of porous vinylpyridine polymer as a weak anion-exchange column packing

Abstract The retention behaviour of aromatic acids on a pyridine polymer column in ion-exchange high-performance liquid chromatography was investigated, and compared with that on a pyridinium polymer column. The effect of the eluent pH on the capacity factor, k ′, of the acids on these polymer columns may be explained by the extent of dissociation of both the solute and the polymer. The relationship between the concentration of methanol in the and k ′ showed that both polymer columns exhibit similar hydrophobic interactions with the solutes. On the pyridine polymer column, good resolution of structural isomers of aminobenzoic and hydroxybenzoic acids was obtained. It is suggested that undissoiciated pyridyl groups contribute to the solute retention.

Preparation and properties of a chelating resin containing the nitrosoresorcinol group.

A macroreticular polystyrene-based chelating resin with the nitrosoresorcinol group as the functional group has been synthesized. The resin shows selectivity for copper(II), iron(III), and cobalt(II). The sorption behaviour of cobalt(II) is examined in detail, with the intention of using the resin analytically. Iron(III) and cobalt(II) are separated in a column operation by stepwise elution with oxalic acid solution and hydrochloric acid respectively.

Characterization of vinylpyridine polymer columns for high-performance liquid chromatography

Abstract Four spherical 2- or 4-vinylpyridine polymers (10–15 μm particle diameter), cross-linked with divinylbenzene and having different surface properties, are proposed as packing materials in high-performance liquid chromatography. The retention behaviour of various compounds on columns packed with these polymers was compared with that on a styrene—divinylbenze copolymer column using methanol as the mobile phase. Interaction between polyhydric phenols and vinylpyridine polymers occurred more effectively in 4-vinylpyridine polymer than 2-vinylpyridine polymer, and porous 4-vinylpyridine polymer with 20% cross-linking provided the best peak resolution in the separation of the phenols. The retentions of acidic and basic compounds were correlated with the extent of acidity or basicity of the compounds. The effect of solvent strength on the retention of the selected compounds was also investigated by using methanol containing water or n-hexane.

Preparation and analytical properties of a chelating resin containing phenylalanine groups

A polystyrene-based macroreticular resin containing phenylalanine groups has been prepared and its analytical properties have been investigated and compared with Dowex A-1. The phenylalanine resin shows high selectivity for mercury(II) and copper(II) in the pH region 2-3. The sorption behaviour of copper has been examined in detail, with the intention of using the resin analytically. The important characteristics of the resin are fast equilibration, high selectivity and small volume change between its hydrogen form and metal forms. These enable it to be applied for the rapid concentration of trace amounts of copper in the presence of large amounts of diverse metals. It may be used for the determination of copper in sea-water and the separation of copper/cobalt and copper/nickel.

Adsorption of mercury(II) on macroreticular styrene—divinylbenzene copolymer beads

The adsorption characteristics of mercury(II) on several kinds of styrene-divinylbenzene copolymer beads having different surface properties were studied. It was found that the polymer beads selectively adsorbed mercury(II) from solutions over a wide range of pH with high efficiency. The amount of mercury(II) adsorbed increased with increase in specific surface area of the polymer beads and the adsorption behaviour was found to be of the Langmuir type. The presence of chloride strongly reduced the adsorption, but this interference was not observed with nitrate, sulphate, perchlorate, cadmium(II), cobalt(II), copper(II), nickel(II), silver(I) and zinc(II). More than 95% of the mercury(II) adsorbed on a column of polymer beads could be recovered with dilute hydrochloric acid.

Preparation of macroreticular anion-exchange resins having spacers and an evaluation of these resins in the synthesis of sulfones

Abstract Three macroporous polystyrene-based anion-exchange resins bearing carbonylalkylammonium groups, - CO ( CH 2 ) n N + ( CH 3 ) 3 , with different lengths of the alkyl spacer, have been prepared and their applicability as solid-phase reagents has been investigated. The resins in their benzenesulfinate forms have been compared with Amberlyst A26. The sulfone yield is affected by the spacer length and the swelling properties of the resins.