L. J. Paliwal

Synthesis, characterization and ion-exchange properties of 4-hydroxyacetophenone, biuret and formaldehyde terpolymer resins

Abstract Terpolymer resins (4-HABF) were synthesized by the condensation of 4-Hydroxy acetophenone and biuret with formaldehyde in the presence of acid catalyst and using varied molar ratios of reacting monomers. Terpolymer resin compositions have been determined on the basis of their elemental analysis and the number average molecular weights of these resins were determined by conductometric titration in non-aqueous medium. Viscometric measurements in dimethyl formamide (DMF) have been carried out with a view to ascertaining the characteristic functions and constant. UV–Vis, IR and NMR spectra were studied to elucidate the structure. Chelation ion-exchange properties of this resin have also been studied employing batch equilibrium method. It was employed to study selectivity of metal ion uptake over a wide pH range and in media of various ionic strength. The overall rate of metal uptake follows the order: Fe 3+ >Cu 2+ >Ni 2+ >Co 2+ =Zn 2+ >Cd 2+ >Pb 2+ >Hg 2+ .

Chelation Ion‐Exchange Properties of a Copolymer Derived from 2‐Hydroxyacetophenone, Oxamide and Formaldehyde

Copolymers (2‐HAOF), synthesized by the condensation of and H2N(O)CC(O)NH2 with CH2O in the presence of acid catalyst, proved to be selective chelating ion‐exchange copolymers for certain metals. The chelating ion‐exchange properties of this copolymer were studied for Cu(II), Ni(II), Co(II), Zn(II), Fe(III), Cd(II) and Pb(II) ions. A batch equilibrium method was employed in the study of the selectivity of metal ion uptake involving the measurements of the distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymer showed a higher selectivity for Fe(III), Cu(II) and Ni(II) ions than for Co(II), Zn(II), Cd(II) and Pb(II) ions.

Synthesis and characterization of copolymer derived from 2-hydroxyacetophenone, oxamide and formaldehyde

Copolymers (2-HAOF) synthesized by the condensation of 2-hydroxy-acetophenone and oxamide with formaldehyde in the presence of acid catalyst and using varied molar ratios of reacting monomers. Copolymer resin compositions have been determined on the basis of their elemental analysis. The number average molecular weights of these copolymers were determined by conductometric titration in non-aqueous media. The viscosity measurements in dimethylformamide (DMF) carried out in order to ascertain the characteristics functions and constants of copolymers. The copolymer resins have been further characterized by absorption spectra in non-aqueous medium, infrared (IR) spectra and nuclear magnetic resonance (NMR) spectral studies.

SYNTHESIS AND STEREOCHEMICAL CHARACTERIZATION OF POLYCHELATES DERIVED FROM β,β′-(2-HYDROXY-5-CHLOROBENZOYL)-p-DIVINYLBENZENE

Polychelates of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) were synthesized from β,β′-(2-hydroxy-5-chlorobenzoyl)-p-divinylbenzene (H2L) and metal salts. All of the chelates are coloured and insoluble in common organic solvents. Their probable structures were determined by visible reflectance spectroscopy and magnetic measurements in conjunction with thermogravimetric and IR spectral studies. Elemental analyses indicate a ligand : metal ratio of 1:1 for all of the polychelates with the association of water molecules except for the Mn(II) polychelate which does not have any water molecules. The half-decomposition temperature of the polychelates decreases in the order: Ni(II) > Cu(II) > Mn(II) > Fe(II) > Co(II) > Zn(II). The electrical conductivities of these chelate polymers have been studied over a wide range of temperatures.

Synthesis and Characterization of Coordination Polymers of 1,2‐bis‐(4‐Thio‐1,3,5‐hexahydro‐1‐triazinyl)ethane

Coordination polymers of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) with the 1,2‐bis‐(4‐thio‐1,3,5‐hexahydro‐1‐triazinyl)ethane (H2BTHTE) ligand have been prepared in DMF solution. The coordination polymers have been characterized by their elemental analyses, magnetic susceptibility and by electronic and infrared spectral measurements. The thermal stability of each polymer was determined by thermogravimetric analysis. The thermal stability of the coordination polymers obtained from the thermograms is in the following order: Fe > Zn > Mn = Co > Ni > Cu. The Cu(II), Co(II), Ni(II) and Fe(II) coordination polymers are of six‐coordinated octahedral geometry while the Mn(II) and Zn(II) coordination polymers are of four‐coordinated tetrahedral structure. The ligand field and nephelauxetic parameters have been determined from the spectra using the ligand field theory of spin‐allowed transitions and which were found to be consistent with six‐coordinated structures for the Cu(II), Co(II), Ni(II) and Fe(II) coordination polymers. Elemental analyses indicate a ligand metal ratio of 1:1 in all of the coordination polymers and the coordination of water molecules with the central metal atom in the case of the Cu(II), Fe(II), Co(II) and Ni(II) coordination polymers.

Ion-exchange properties of 4-hydroxyacetophenone-biuret-formaldehyde tercopolymer

Abstract Terpolymers prepared by condensation of 4-hydroxyacetophenone and biuret with formaldehyde in presence of acid catalyst (2M HCl) proved to be selective chelating ion exchange resins for certain metal ions. Chelation ion exchange properties of these terpolymers were studied for Cu2+, Ni2+, Co2+, Fe3+, Zn2+, Cd2+ and Pb2+ ions. A batch equilibrium method was employed in the study of the selectivity of metal ion uptake involving the measurements of distribution of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The terpolymers showed a higher selectivity for Fe3+, Cu2+ and Ni2+ ions than for Co2+, Zn2+, Cd2+, Hg2+ and Pb2+ ions.

Chelation ion-exchange properties of copolymer derived from 4-hydroxyacetophenone, oxamide and formaldehyde

Abstract A copolymer (4-HAOF) prepared by condensation of 4-hydroxyacetophenone and oxamide with formaldehyde in the presence of an acid catalyst proved to be a selective chelating ion-exchange copolymer for certain metals. Chelating ion-exchange properties of this copolymer were studied for Fe 3+ , Cu 2+ , Ni 2+ , Co 2+ , Zn 2+ , Cd 2+ , Pb 2+ and Hg 2+ ions. A batch equilibrium method was employed in the study of the selectivity of metal ion uptake involving the measurements of the distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymer showed higher selectivity for Fe 3+ ions than for Co 2+ , Zn 2+ , Cd 2+ , Pb 2+ , Cu 2+ , Ni 2+ and Hg 2+ ions.