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Totally found 12172 items.

  • [期刊] Preparation of Dicyandiamide Modified Polystyrene Resin Beads Decorated With Nano-Fe3O4 for Removing Hg(II) From Aqueous Solution
    In this study, dicyandiamide (DCDA) modified polystyrene (PS) resin beads decorated with nano-Fe3O4 (Fe3O4-PS-DCDA hybrids) were prepared by co-precipitation method. The Fe3O4-PS-DCDA hybrids were characterized by scanning electron microscopy (SEM), Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) spectroscopy, X-ray photoelectron spectroscopy (XPS), nitrogen adsorption/desorption isotherms, and vibrating sample magnetometer (VSM). Meanwhile, the adsorption property of Fe3O4-PS-DCDA hybrids for Hg(II) in aqueous solution was investigated by batch methods. The results show that the nano-Fe(3)O(4 )decorated on the outer surface and interior of DCDA modified PS resin beads (PS-DCDA) is nanoparticles and nanorods, respectively. The saturation magnetization (M-s) of the Fe3O4-PS-DCDA hybrids is 0.70 emu/g, which is enough to ensure the convenient magnetic separation. The adsorption kinetics of the hybrids for Hg(II) accorded with the pseudo-second-order model and the adsorption isotherms followed the Freundlich equation. (C) 2016 Society of Plastics Engineers
  • [期刊] CuCl2 heterogenized on metformine-modified polystyrene resin as an antibacterial agent and recyclable nanocatalyst for Ullmann-type C-N coupling reactions
    Merrifield Resin was functionalized with metformine and applied as a solid support to immobilize the CuCl2. The Ps-Met/CuCl2 was characterized by several techniques including Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), wavelength-dispersive X-ray spectroscopy (WDX) and inductively coupled plasma (ICP). The Ps-Met/CuCl2 was used as an efficient recyclable solid nanocatalyst for N-arylation of indole and aniline through coupling reactions of Ullmann-type C-N. The advantages of this method are easy workup, improved yields, and simple recovery via filtration. Ultimately, the Ps-Met/CuCl2 antibacterial property was examined against two bacteria (Staphylococcus aureus (Staph. aureus) and Escherichia coli (E. coli)) and indicated its antibacterial performance against gram negative (E. coli) bacteria and gram positive (Staph. aureus).
  • [期刊] Microwave assisted hydrogenation of olefins by Pd NPs@polystyrene resin using a gas addition kit: a robust and sustainable protocol
    Polystyrene (PS) resin bead supported palladium nanoparticles (Pd NPs@PS resin) were prepared and their catalytic activity for the hydrogenation of olefins was investigated under microwave heating. The hydrogenation of styrene was effectively carried out in EtOH/H2O, in the presence of 0.00035 mmol of the catalyst to afford the corresponding ethylbenzene in high yield within 20 min under microwave heating. The catalyst efficiency measured in terms of turn over number (TON) and turn over frequency (TOF) was found to be 2829 and 8573 (h(-1)), respectively. The encapsulated palladium nanoparticles were easily recovered by a simple filtration method and reused several times without significant loss in their catalytic activity. Further, the method showed a wide substrate scope under mild reaction conditions, making it a green versatile and highly sustainable protocol.
  • [期刊] Heat-resistant polystyrene resin
    plastics & packaging; V.46 N.6 2001; 90
  • [期刊] Polystyrene Resin Functionalized with a Piperazine: An Efficient and Reusable Catalyst for Multi-Component Synthesis of Polyfunctionalized 4H-Pyran Derivatives
    Background: A novel one pot protocol has been developed to synthesize polyfunctionalized 4H-pyran derivatives directly from corresponding substituted aldehyde, malononitrile and β-keto ester using a recyclable polystyrene resin functionalized with a piperazine. The significant features of the present protocol are environmental acceptability, operational simplicity, shorter re-action time, high yields, and no chromatographic separation. The polymer catalyst was recovered and reused for four times without a noticeable decrease in the catalyst activity. Methods: All products were characterized using melting point, HRMS, ~1H and ~(13)C NMR techniques. Results: The various catalysts were compared with resin bound piperazine under optimized reaction conditions and it was found that resin bound piperazine gave better yield of desired product and it was a recyclable catalyst. Different reaction parameters such as solvent, temperature, time were studied to achieve optimal catalyst performance using resin bound piperazine as a catalytic system. Conclusion: We have demonstrated that resin bound piperazine is an excellent catalyst for the synthesis of 477-pyran derivatives. The product was isolated by simple filtration process. Also the catalyst was recovered, recycled and reused.
  • [期刊] Epoxidation of styrene catalyzed by manganese (Ⅲ) porphyrins supported on chloromethylated polystyrene resin bearing crown ether groups
    Metalloporphyrins and crown ether groups were simultaneously supported on chloromethylated polystyrene resin to produce a series of polymer-supported catalysts. The synthesis of these catalysts has been studied. The influence of pH, concentrations of NaOCl and phase transfer catalysts on the epoxidation of styrene catalyzed by these catalysts has also been investigated. The experimental results show that manganese(Ⅲ) porphyrin bound to chloromethylated polystyrene which bears crown ether groups is effective catalysts for the epoxidation of styrene by sodium hypochlorite. The introduction of crown ether groups increases the catalytic efficiency of supported metalloporphyrins. The kinetics of epoxidation catalyzed by supported manganese(Ⅲ) porphyrins obeys Michaelis-Menten equation—the characteristic of enzyme-driven reaction.
  • [期刊] The ion chromatographic separation of high valence metal cations using a neutral polystyrene resin dynamically modified with dipicolinic acid
    A neutral polystyrene resin column,dynamically loaded with dipicolinic acid at a concentration of 0.1 mM in 1 M potassium nitrate eluent, was investigated for the separation characteristics of a numver of high valence metal cations over the pH range 0-3.The metal species studied were Th(IV),U(VI),Zr(IV),Hf(IV),Sn(IV),Sn(IV),V(IV) and V(V)Fe(III)and Bi(III),of which Ti(IV),Sn(IV),V(IV)and Fe(III)did not not show any retention. For the remaining metal ions,significant retention was obtained with good peak shapes,except for Th(IV),which moved only slightly from the solvent front with some tailing. The retention order at pH 0.3 was Th(IV)
  • [期刊] Immobilization of iron phthalocyanine on 4-aminopyridine grafted polystyrene resin as a catalyst for peroxymonosulfate activation in eliminating tetracycline hydrochloride
    A distinctive catalyst R-N-Fe was synthesized by anchoring iron phthalocyanine (FePc) covalently on chloromethylated polystyrene beads, which were pre-functionalized by 4-aminopyridine (4-ampy). Herein, pyridyl groups grafted on resins act as the axial fifth ligands to coordinate with FePc molecules. The obtained catalyst was characterized using N-2 adsorption-desorption, Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), and zeta potential. The catalytic system based on peroxymonosulfate (PMS) activation was effective and stable for tetracycline hydrochloride (TCH) degradation, and activation energy of the TCH elimination using PMS activated by R-N-Fe was estimated to be 38.79 kJ/mol. Additionally, electron paramagnetic resonance (EPR) measurement combined with three different radical scavengers (ascorbic acid, methanol and tert-butyl alcohol) was conducted to confirm that sulfate radical (SO4 center dot-) and hydroxyl radical ((OH)-O-center dot) served as the main active species in the presence of PMS. Current findings suggested that the R-N-Fe/PMS system was a promising approach for the elimination of pharmaceutical compounds from aqueous solution.
  • [期刊] Efficient, non-acidolytic method for the selective cleavage of N-Boc amino acid and peptide phenacyl esters linked to a polystyrene resin
    An efficient, non-acidolytic method for the selective cleavage of phenacyl esters of N-Boc-amino acids and -peptides linked to a polystyrene resin by (CH3)(3)SnOH (TMTOH) or [(n-C4H9)(3)Sn](2)O (BBTO) is described, We highly recommend the use of trimethyltin hydroxide for the selective cleavage of carboxylic esters based on its favourable properties, The method is compatible with an N-Boc/O-Bn (benzyl ether) strategy and yields enantiomerically pure N-Boc-peptides useful for further manipulation, for segment condensations or for cyclization strategies, A mechanism for the cleavage of methyl phenylacetate in solution by TMTOH is postulated. [References: 42]
  • [期刊] Immobilization of iron phthalocyanine on 4-aminopyridine grafted polystyrene resin as a catalyst for peroxymonosulfate activation in eliminating tetracycline hydrochloride
    A distinctive catalyst R-N-Fe was synthesized by anchoring iron phthalocyanine (FePc) covalently on chloromethylated polystyrene beads, which were pre-functionalized by 4-aminopyridine (4-ampy). Herein, pyridyl groups grafted on resins act as the axial fifth ligands to coordinate with FePc molecules. The obtained catalyst was characterized using N-2 adsorption-desorption, Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), and zeta potential. The catalytic system based on peroxymonosulfate (PMS) activation was effective and stable for tetracycline hydrochloride (TCH) degradation, and activation energy of the TCH elimination using PMS activated by R-N-Fe was estimated to be 38.79 kJ/mol. Additionally, electron paramagnetic resonance (EPR) measurement combined with three different radical scavengers (ascorbic acid, methanol and tert-butyl alcohol) was conducted to confirm that sulfate radical (SO4 center dot-) and hydroxyl radical ((OH)-O-center dot) served as the main active species in the presence of PMS. Current findings suggested that the R-N-Fe/PMS system was a promising approach for the elimination of pharmaceutical compounds from aqueous solution.
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