Reactive Polymers, Ion Exchangers, Sorbents最新文献

A polymer-bound phenanthroline palladium catalyst,

Several porphyrins and metalloporphyrins have been reversibly and covalently attached to a functionalized insoluble polystyrene matrix, α-[(4-bromomethyl-3-nitrobenzamido)benzyl]-poly(styrene-co-divinylbenzene). Insertion and removal of Zn(II) on the supported species has been successfully achieved. The products have been identified by alkaline detachment as well as spectroscopically.

Microporous polybenzimidazole of 250–500 μm bead size from Celanese has been epoxidized and subsequently aminolyzed with ethylenediamine and diethylenetriamine to obtain sorbents having high capacity, selectivity and sorption rate for ferric ion from acidic sulfate solutions. The ferric ion sorption capacity of these sorbents is more than twice that obtained with normal chelating resins. The chelation properties of the new sorbents can be used as a means of removing the ferric ion selectivity from mixtures in acidic sulfate solution containing a wide range of mono- and multivalent metal ions, including some which normally form strong chelate complexes.

Zirconium phosphate-phosphite of composition Zr(HPO₄)_0.7(HPO₃)_1.3 · 0.5H₂O possesses a peculiar layer structure in which there is a regular alternation of an interlayer region of zirconium phosphate type with another of zirconium phosphite type. The ion-exchange properties of this particular inorganic layered compound towards alkali metal ions have been examined and many comparisons with analogous properties of α-zirconium phosphate are reported. It was found that, although only the phosphate regions are involved in the ion exchange processes, the presence of the adjacent phosphite regions strongly affects both the selectivity and rate of exchange as well as the phase transitions occurring in the salt conversion. A discussion of the different ion-exchange processes taking place in the phosphate regions of zirconium phosphate-phosphite and in the same regions of the pure α-zirconium phosphate is made on the basis of the particular layered structure of α-zirconium phosphate phosphite. Although the ion-exchange capacity of this latter exchanger is less than one half of that of pure α-Zr(HPO₄)₂ · H₂O, it can be considered a better exchanger for large cations.

When poly(chlorotrifluoroethylene) is reacted with the dianion of 3-mercaptopropionic acid, a substituted polymer with pendant carboxylic acid functionality is produced. Further reactions, such as esterification and reduction to the alcohol, can be performed on the acid groups. Chemical transformation of the alcohol produced the corresponding tosylate, halide, trimethylsiloxy, and trichloroacetate derivatives. By increasing the variety of functionality available, the possible utilizations of these polymers as reactive polymers and as solid phases in chromatography are thus increased.

Experimental results are provided to show that a modified strong-base resin with tripropyl quaternary ammonium functionality offers greater chromate selectivity and improved efficiency of regeneration over widely used commercially available anion-exchange resins with trimethyl quaternary ammonium or dimethyl tertiary amine functionality. Use of this new, modified resin is likely to be more economic for decontaminating chromate-laden industrial wastewaters.

Weak-base poly(diallylamine) resins have been synthesised and tested for gold adsorption properties in metal-containing solutions ranging all the way from strong acid (aqua regia) to strong base (complex cyanide solutions, pH 7–14). These resins show high capacity, up to 5 mmol/g dry resin, and good gold-selective properties for much of this pH range and in many different types of solution, including contaminated wastes. However, the slow dissolution of uncrosslinked polymer chains trapped in the resin matrix limits the gold adsorption properties at low gold concentrations (below 5 mg/dm³).