Chelation Ion-exchange Properties Research Articles

Synthesis and characterization of 2-hydroxy-4-methoxyacetophenoneurea-formaldehyde resins and their ion-exchange properties

Resins were prepared by condensing 2-hydroxy-4-methoxyacetophenone (2-H-4-MAc) with urea and formaldehyde in the presence of 2 M HCl/2 M H2SO4 catalyst with varying molar ratios of reacting monomers. The resin samples were characterized by elemental analyses and IR spectral studies.\(\bar M_n \) was determined by vapour pressure osmometry and non-aqueous conductometric titration in pyridine. Viscosity measurements of the resin samples were carried out in dimethylformamide. Chelation ion-exchange properties of 1∶1 resin for selected metal ions have also been studied employing the batch-equilibration method. This method involved the measurement of distribution of a given metal between a resin sample and a solution containing metal ions. The study was carried out over a wide pH range and in media of differing ionic strengths.

Synthesis and characterization of 2, 4-dihydroxy-benzaldehydeoxime-formaldehyde polymers and their application as ion-exchangers

Polymers were prepared by the condensation of 2, 4-dihydroxybenzaldehydeoxime (2, 4-DBO) and formaldehyde (F) in the presence of oxalic acid as catalyst with varying molar ratios of reacting monomers. Polymers were characterized by their IR spectra, elemental analyses, TGA and Mn as determined by vapour pressure osmometry as well as by non-aqueous conductometric titrations. Viscosity measurements of the solutions of polymer samples were carried out in dimethylformamide. Chelation ion-exchange properties have also been studied employing the batch equilibration method. This method involved the measurement of distribution of a given metal between the polymer sample and a solution containing metal ions. The study was carried out over a wide pH range and in media of various ionic strengths. The polymer showed a higher selectivity for UO22+ and Fe3+ ions than for Cu2+, Ni2+, Co2+ and Mn2+ ions.

Friedel-Crafts Polymers. 6. Friedel-Crafts Polycondensation of p-Xylylerte Dibromide with Salicylic Acid and β-Resorcyiic Acid

Abstract Polymers were prepared by condensing p-xylylene dibromide separately with salicylic acid and β-resorcylic acid in the presence of anhydrous ferric chloride in dioxane. The polymer samples_were characterized by elemental analysis, by IR spectral study, by M determined by vapor pressure osmometry, by nonaqueous conducto-metric titration in pyridine, by TGA in air, and by viscosity measurements of polymer solutions in DMF. Polymeric metal chelates of Cu2+, Co2+, Zn2+, Ni2+, and Fe3+ with polymer samples were prepared and characterized by elemental analysis, by IR spectral study, and by TGA in air. The chelation ion-exchange properties of the polymer samples were studied by employing the batch equilibration method.

P-Hydroxybenzoic Acid-Urea-Formaldehyde Copolymers and Their Ion-Exchange Properties

Abstract Copolymers (PUF) were synthesized by the condensation of p-hydroxybenzoic acid (P), urea (U), and formaldehyde (F), in the presence of different acidic catalysts and using varied molar ratios of reacting monomers. One of the copolymers having the highest molecular weight was fractionated. Copolymer compositions have been determined on the basis of their elemental analysis and conductometric titrations in the nonaqueous phase. Molecular weights (Mn) have been estimated by VPO. Copolymer prepared by using the stoichiometric properties of the monomers and HCI as catalyst furnished the highest molecular weight (Mn). The viscosity measurements carried out in DMF indicate normal behavior. TGA and DSC data were analyzed to compare the relative thermal stability and estimate the characteristic parameters. IR spectra were studied to elucidate the structure. Chelation ion-exchange properties have also been studied employing the batch equilibration method. The order of selectivity of metal ions by the copol...

Chelation ion-exchange properties of salicylic acid-urea-formaldehyde copolymers

Chelation ion-exchange properties of copolymers prepared from salicylic acid, urea and formaldehyde by condensation in presence of acid catalyst were studied for Cu2+, Fe3+, UO2+, Mn2+,Zn2+ and Co2+ ions. A batch equilibration method was adopted to study the selectivity of metal ion uptake. This method involved the measurement of distribution of a given metal between the copolymer sample and a solution containing the metal ions. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymer showed a higher selectivity for UO22+, Cu2+ and Fe3+ ions than Mn2+, Co2+ and Zn2+ ions.

Chelating ion-exchangers containing 4-(2-pyridylazo)-resorcinol as the functional group

The synthesis of a cross-linked polystyrene-azo-PAR resin, and its chelating ion-exchange properties with nine ionic species, are described. A resin structure, containing both PAR and azophenol chelating groups is proposed. The effects on capacity of varying ionic concentration and the nature of the co-ion were studied.