Copper(I) bromide coordinated by the ionic liquid 1‐[(diethyl amine)amine]ethyl‐3‐methyl imidazolium chloride to catalyze the atom transfer radical polymerization of methyl methacrylate in 1‐allyl‐3‐methyl imidazolium chloride

A coordinating ionic liquid (IL), 1‐[(diethyl amine)amine]ethyl‐3‐methyl imidazolium chloride ([N₃MIM]Cl), was prepared as an alternative to a simple organic ligand to coordinate to copper(I) bromide (CuBr). We, thereby, obtained a novel catalyst for atom transfer radical polymerization (ATRP) reactions. This catalyst was applied to the ATRP of methyl methacrylate in the IL 1‐allyl‐3‐methyl imidazolium chloride ([AMIM]Cl). The chemical structures of the ILs obtained were confirmed by Fourier transform infrared spectroscopy, mass spectrometry, and ¹H‐NMR analyses. The coordination ability of [N₃MIM]Cl was assessed by cyclic voltammetry, and the redox potential of [N₃MIM]Cl–CuBr was ?0.507 V. The [N₃MIM]Cl–CuBr complex was expected to be a markedly more active catalyst than the amine DETA–CuBr complex. The coordination mode toward CuBr was also examined. The [N₃MIM]Cl–CuBr catalyst system showed good controllability in the aforementioned ATRP reaction in [AMIM]Cl. The Cu catalyst was easily separated from the obtained polymer with the coordinating IL as a ligand. Consequently, the coordinating IL overcame the shortcomings of traditional organic ligands, such as poor compatibility with IL media and poor separation of the catalyst from the polymer; this makes it highly promising for applications in the ATRP field. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45484.     

Photo‐Induced atom transfer radical polymerization with nanosized α‐Fe2O3 as photoinitiator

Photo‐induced atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was achieved in poly(ethylene glycol)‐400 with nanosized α‐Fe₂O₃ as photoinitiator. Well‐defined poly(methyl methacrylate) (PMMA) was synthesized in conjunction with ethyl 2‐bromoisobutyrate (EBiB) as ATRP initiator and FeCl₃·6H₂O/Triphenylphosphine (PPh₃) as complex catalyst. The photo‐induced polymerization of MMA proceeded in a controlled/living fashion. The polymerization followed first‐order kinetics. The obtained PMMA had moderately controlled number‐average molecular weights in accordance with the theoretical number‐average molecular weights, as well as narrow molecular weight distributions (M_w/M_n). In addition, the polymerization could be well controlled by periodic light‐on–off processes. The resulting PMMA was characterized by ¹H nuclear magnetic resonance and gel permeation chromatography. The brominated PMMA was used further as macroinitiator in the chain‐extension with MMA to verify the living nature of photo‐induced ATRP of MMA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42389.     

Synthesis and characterization of novel core‐shell magnetic nanogels based on 2‐acrylamido‐2‐methylpropane sulfonic acid in aqueous media

Ultrafine well‐dispersed Fe₃O₄ magnetic nanoparticles were directly prepared in aqueous solution using controlled coprecipitation method. The synthesis of Fe₃O₄/poly (2‐acrylamido‐2‐methylpropane sulfonic acid) (PAMPS), Fe₃O₄/poly (acrylamide‐co‐2‐acrylamido‐2‐methylpropane sulfonic acid) poly(AM‐co‐AMPS) and Fe₃O₄/poly (acrylic acid‐co‐2‐acrylamido‐2‐methylpropane sulfonic acid) poly(AA‐co‐AMPS) ‐core/shell nanogels are reported. The nanogels were prepared via crosslinking copolymerization of 2‐acrylamido‐2‐methylpropane sulfonic acid, acrylamide and acrylic acid monomers in the presence of Fe₃O₄ nanoparticles, N,N′‐methylenebisacrylamide (MBA) as a crosslinker, N,N,N′,N′‐tetramethylethylenediamine (TEMED) and potassium peroxydisulfate (KPS) as redox initiator system. The results of FTIR and ¹H‐NMR spectra indicated that the compositions of the prepared nanogels are consistent with the designed structure. X‐ray powder diffraction (XRD) and transmission electron microscope (TEM) measurements were used to determine the size of both magnetite and stabilized polymer coated magnetite nanoparticles. The data showed that the mean particle size of synthesized magnetite (Fe₃O₄) nanoparticles was about 10 nm. The diameter of the stabilized polymer coated Fe₃O₄ nanogels ranged from 50 to 250 nm based on polymer type. TEM micrographs proved that nanogels possess the spherical morphology before and after swelling. These nanogels exhibited pH‐induced phase transition due to protonation of AMPS copolymer chains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of copolymer grafted magnetic nanoparticles via surface‐initiated nitroxide‐mediated radical polymerization

“Grafting from” surface‐initiated nitroxide‐mediated radical polymerization (SI‐NMRP) techniques were used to synthesize poly[styrene‐co‐(maleic anhydride)] copolymer brushes from the Fe₃O₄ surfaces. Well‐defined polymer chains were grown from the Fe₃O₄ surfaces to yield particles with a Fe₃O₄ core and a polymer outer layer. The observed narrow molecular weight distributions (M_w/M_n), linear kinetic plots and linear plots of molecular weight (M_n) versus conversion for the free polymer indicated that the chain growth from the Fe₃O₄ surface was a controlled process by adding an excess of 2,2,6,6‐tetramethylpiperidinyloxy (TEMPO). The modified nanoparticles were subjected to detailed characterization using XRD, TEM, FT‐IR, and TGA. The analyses of vibration sample magnetometer (VSM) verified that the nanoparticles owned good magnetic property. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Preparation and characterization of magnetic star‐shaped amphiphilic copolymer nanoparticles of S‐Fe3O4‐PLA‐b‐MPEG

Magnetic star‐shaped amphiphilic copolymers (S‐Fe₃O₄‐PLA‐b‐MPEG) consisting of Fe₃O₄ as the core, poly(L ,D ‐lactide) (PLA) as the inner layer, and monomethyl polyethylene glycol (MPEG) as the out shell were synthesized. The syntheses included ring‐opening polymerization of L ,D ‐lactide initiated by hydroxyl modified Fe₃O₄ (Fe₃O₄‐(OH) _n), followed by the esterification of the PLA with MPEG. The structure of the star block copolymers were characterized by Fourier Transform infrared spectroscopy, thermogravimetric analysis, X‐ray diffraction, transmission electron microscopy, nanoparticle size analyzer, and vibrating sample magnetometer. The nanoparticles in aqueous solution were made from the amphiphilic star copolymer. The average size of the nanoparticles was adjustable and increased with the increase of the PLA segments in the copolymer. The cytotoxicity grade of the nanoparticles was zero determined by the analysis of cytotoxicity. The nanoparticles could potentially be used as the drug vehicles for magnetic‐response controlled release. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

A facile strategy for the functionalization of poly[cyclotriphosphazene‐co‐(4,4′‐sulfonyldiphenol)] materials

Recently, a new type of phosphazene‐containing material, poly[cyclotriphosphazene‐co‐(4,4′‐sulfonyldiphenol)] (PZS), was successfully prepared. PZS materials including PZS nanotubes, PZS nanofibers and PZS microspheres show excellent thermal stability, biocompatibility and biodegradability. Moreover, PZS‐containing materials such as silver nanowire/PZS, carbon nanotube/PZS and Fe₃O₄/PZS nanotubes have also been prepared. Therefore, we explored a specific method for the functionalization of these PZS and PZS‐containing materials to expand their scope of application. As a model of various PZS and PZS‐containing materials, PZS microspheres (PZSMs) were functionalized via surface‐initiated atom transfer radical polymerization (ATRP). Polymerization of styrene occurred at surface sites covalently derivatized with ATRP initiators to form PZSM–polystyrene. The number‐average molecular weight (M_n) of grafted polymer chains could be well controlled. Furthermore, PZSM–polystyrene was still active for further block copolymerization of methyl methacrylate. Both styrene‐ and acrylate‐type monomers could be directly polymerized or block copolymerized from the surface of PZS and PZS‐containing materials using surface‐initiated ATRP. M_n of grafted polymer chains could be well controlled. This facile strategy could pave the way for a wider range of applications of these materials. Copyright © 2010 Society of Chemical Industry     

Post‐Plasma Catalysis for Methane Partial Oxidation to Methanol: Role of the Copper‐Promoted Iron Oxide Catalyst

Methane‐air partial oxidation to methanol over a ceramic‐supported Fe₂O₃‐CuO catalyst was investigated in a post‐plasma catalytic reactor at ambient conditions. The multicomponent catalyst exerted a better catalytic performance than the monocomponent Fe₂O₃ catalyst. Characterization of the catalysts by XPS showed that incorporation of the CuO additive to a Fe₂O₃‐based catalyst resulted in an increase of lattice oxygen in the surface of the catalyst which facilitated selective methane oxidation. Hydrogen temperature‐programmed reduction revealed that addition of the CuO promoter could improve the reduction performance of the catalyst. Moreover, this catalyst showed excellent stability and resistance against carbon deposition in the extended reactions while maintaining catalytic activity. A post‐plasma catalytic mechanism is proposed with three main pathways to methanol synthesis.     

Carboxyl‐containing polyarylene ether nitrile/Fe3O4 hybrids and their effects on the PEN composites

In this study, the novel polyarylene ether nitrile containing carboxyl groups (CPEN)/Fe₃O₄ hybrids were synthesized via the solvent‐thermal route. The SEM and TEM images showed that the surface of functionalized Fe₃O₄ hybrids (CPEN‐f‐Fe₃O₄) became rough and coated with a thin polymer layer successfully. Chemical bonds were formed between the carboxyl groups and Fe₃O₄ spheres, which were characterized by FTIR and XRD. Series of PEN composite films were prepared through solution‐casting method with different contents of CPEN‐f‐Fe₃O₄ hybrids and raw Fe₃O₄ spheres. The SEM images showed that the CPEN‐f‐Fe₃O₄ hybrids became much more dispersible and compatible in PEN matrix than that of raw Fe₃O₄ spheres, which was further confirmed by rheological study. The magnetic analysis showed that the saturation magnetization of composites films increased with the increase of CPEN‐f‐Fe₃O₄ hybrids loading content. The results of thermogravimetric and mechanical study exhibited that the composite films had good thermal stability and mechanical property. POLYM. COMPOS., 36:1325–1334, 2015. © 2014 Society of Plastics Engineers     

Millimeter‐size polyethylene hollow spheres synthesized with MgCl2‐supported Ziegler‐Natta catalyst

Polyethylene hollow spheres with diameters of 0.4–2 mm were synthesized by a two‐step slurry polymerization in a single reactor with a spherical MgCl₂‐supported Ziegler‐Natta catalyst activated by triethylaluminum, in which the first step was prepolymerization with 0.1 MPa propylene and the second step was ethylene polymerization under 0.6 MPa. The prepolymerization step was found necessary for the formation of hollow spherical particles with regular shape (perfectly spherical shape). The effects of adding small amount of propylene (propylene/ethylene < 0.1 mol/mol) in the reactor after the prepolymerization step were investigated. Average size of the polymer particles was increased, and the polymerization rate was markedly enhanced by the added propylene. Development of the particle morphology with polymerization time was also studied. The polymer particles formed by less than 20 min of ethylene polymerization showed hollow spherical morphology with thin shell layer. Most of the particles had ratio of shell thickness/particle radius smaller than 0.5. By prolonging the ethylene polymerization, the shell thickness/particle radius ratio gradually approached 1, and the central void tended to disappear. Central void in polymer particles formed from smaller catalyst particles disappeared after shorter time of polymerization than those formed from bigger catalyst particles. The shell layer of the hollow particles contained large number of macro‐, meso‐ and micro‐pores. The mesopore size distributions of four typical samples were analyzed by nitrogen adsorption–desorption experiments. A simplified multigrain model was proposed to explain the morphogenesis of the hollow spherical particles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43207.     

Statistical Optimization of the Biodiesel Production Process Using a Magnetic Core‐Mesoporous Shell KOH/Fe3O4@γ‐Al2O3 Nanocatalyst

A magnetic core‐mesoporous shell KOH/Fe₃O₄@γ‐Al₂O₃ nanocatalyst was synthesized using the Fe₃O₄@γ‐Al₂O₃ core‐shell structure as support and KOH as active component. The prepared samples were characterized by X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FE‐SEM), energy‐dispersive X‐ray spectroscopy (EDS), Fourier transform infrared (FTIR), Brunauer‐Emmett‐Teller (BET), and vibrating sample magnetometry (VSM) techniques. Transesterification of canola oil to methyl esters (biodiesel) in the presence of the magnetic core‐mesoporous shell KOH/Fe₃O₄@γ‐Al₂O₃ nanocatalyst was investigated. Response surface methodology (RSM) based on the Box‐Behnken design (BBD) was employed to optimize the influence of important operating variables on the yield of biodiesel. A biodiesel yield of 97.4 % was achieved under optimum reaction conditions. There was an excellent agreement between experimental and predicted results.     

Fe3O4@mesoporouspolyaniline: A Highly Efficient and Magnetically Separable Catalyst for Cross‐Coupling of Aryl Chlorides and Phenols

A high surface, magnetic Fe₃O₄@mesoporouspolyaniline core‐shell nanocomposite was synthesized from magnetic iron oxide (Fe₃O₄) nanoparticles and mesoporouspolyaniline (mPANI). The novel porous magnetic Fe₃O₄ was obtained by solvothermal method under sealed pressure reactor at high temperature to achieve high surface area. The mesoporouspolyaniline shell was synthesized by in situ surface polymerization onto porous magnetic Fe₃O₄ in the presence of polyvinylpyrrolidone (PVP) and sodium dodecylbenzenesulfonate (SDBS), as a linker and structure‐directing agent, through ‘blackberry nanostructures’ assembly. The material composition, stoichiometric ratio and reaction conditions play vital roles in the synthesis of these nanostructures as confirmed by variety of characterization techniques. The role of the mesoporouspolyaniline shell is to stabilize the porous magnetic Fe₃O₄ nanoparticles, and provide direct access to the core Fe₃O₄ nanoparticles. The catalytic activity of magnetic Fe₃O₄@mesoporousPANI nanocomposite was evaluated in the cross‐coupling of aryl chlorides and phenols.     

α‐Bis and α,ω‐tetrakis(4‐dimethylaminophenyl) functionalized polymers by atom transfer radical polymerization using 1,1‐bis[(4‐dimethylamino)phenyl]ethylene as tertiary diamine initiator precursor and functionalizing agent

The quantitative syntheses of α‐bis and α,ω‐tetrakis tertiary diamine functionalized polymers by atom transfer radical polymerization (ATRP) methods are described. A tertiary diamine functionalized 1,1‐diphenylethylene derivative, 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1), was evaluated as a unimolecular tertiary diamine functionalized initiator precursor as well as a functionalizing agent in ATRP reactions. The ATRP of styrene, initiated by a new tertiary diamine functionalized initiator adduct (2), affords the corresponding α‐bis(4‐dimethylaminophenyl) functionalized polystyrene (3). The tertiary diamine functionalized initiator adduct (2) was prepared in situ by the reaction of (1‐bromoethyl)benzene with 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1) in the presence of a copper (I) bromide/2,2′‐bipyridyl catalyst system. The ATRP of styrene proceeded via a controlled free radical polymerization process to afford quantitative yields of the corresponding α‐bis(4‐dimethylaminophenyl) functionalized polystyrene derivative (3) with predictable number‐average molecular weight (M_n) and narrow molecular weight distribution (M_w/M_n) in a high initiator efficiency reaction. The polymerization process was monitored by gas chromatography analysis. Quantitative yields of α,ω‐tetrakis(4‐dimethylaminophenyl) functionalized polystyrene (4) were obtained by a new post ATRP chain end modification reaction of α‐bis(4‐dimethylaminophenyl) functionalized polystyrene (3) with excess 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1). The tertiary diamine functionalized initiator precursor 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1) and the different tertiary amine functionalized polymers were characterized by chromatography, spectroscopy and non‐aqueous titration measurements. Copyright © 2012 Society of Chemical Industry     

Fabrication,characterization, and properties of poly(ethylene‐co‐vinyl acetate)/magnetite nanocomposites

Poly(ethylene‐co‐vinyl acetate) (EVA)/magnetite (Fe₃O₄) nanocomposite was prepared with different loading of Fe₃O₄ nanoparticles. The mixing and compounding were carried out on a two‐roll mixing mill and the sheets were prepared in a compression‐molding machine. The effect of loading of nanoparticles in EVA was investigated thoroughly by different characterization technique such as transmission electron microscopy (TEM), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), limiting oxygen index (LOI), and technological properties. TEM analysis showed the uniform dispersion of filler in the polymer matrix and the dispersion of filler decreased with increase in filler content. XRD of the nanocomposite revealed the more ordered structure of the polymer chain. An appreciable increase in glass transition temperature was observed owing to the restricted mobility of Fe₃O₄‐filled EVA nanocomposite. TGA and flame resistance studies indicated that the composites attain better thermal and flame resistance than EVA owing to the interaction of filler and polymer segments. Mechanical properties such as tensile strength, tear resistance, and modulus were increased for composites up to 7 phr of filler, which is presumably owing to aggregation of Fe₃O₄ nanoparticle at higher loading. The presence of Fe₃O₄ nanoparticles in the polymer matrix reduced the elongation at break and impact strength while improved hardness of the composite than unfilled EVA. The change in technological properties had been correlated with the variation of polymer–filler interaction estimated from the swelling behavior. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40116.     

Affinity‐tuned peroxidase‐like activity of hydrogel‐supported Fe3O4 nanozyme through alteration of crosslinking concentration

In this work, we evaluated the effect of crosslinking concentration on the affinity of poly (2‐acrylamido‐2‐methyl‐1‐propansulfonic acid) (PAMPS) hydrogel‐supported Fe₃O₄ nanozyme towards substrates (tetramethylbenzidine (TMB) and H₂O₂). The peroxidase‐like catalytic activity of PAMPS/Fe₃O₄ nanozyme was discussed with respect to crosslinking concentration of PAMPS hydrogel for the oxidation of TMB in the presence of H₂O₂ at room temperature. High catalytic activity was achieved due to good dispersion of Fe₃O₄ nanozyme in the hydrogel network and strong affinity of PAMPS hydrogel‐supported Fe₃O₄ nanozyme towards substrates. The affinity between the hydrogel‐supported Fe₃O₄ nanozyme and substrates can be improved by regulating the crosslinking concentration of PAMPS hydrogel without other trenchant experimental conditions. In addition, the result indicated that H₂O₂ can be detected even at a concentration as low as 1.5 × 10^?6 mol L^?1 with a linear detection range of 1.5–9.8 × 10^?6 mol L^?1. Such investigations not only showed a new approach to improve the affinity and peroxidase‐like activity of Fe₃O₄ nanozyme, but also verified its potential application in bio‐detection and environmental chemistry. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43065.     

Preparation and characterization of OH‐functionalized magnetic nanogels under UV irradiation

A novel preparation method of net magnetic polymer nanogels with swollen shell was developed. UV‐induced photopolymerization of 2‐hydroxyethyl methacrylate (HEMA) was performed in the magnetite aqueous suspension, free of any additive to obtain monodisperse magnetic nanogels with swollen shell. Owing to the step‐growth polymerization of the monomer, the particle size of magnetic nanogels can be conveniently manipulated by changing the irradiation time and the volume of the monomer dropped. The crystalline structure of Fe₃O₄ core and chemical composition of PHEMA magnetic nanogels were characterized by using X‐ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis, respectively. Particle sizes, size distributions of magnetic nanogels in swollen state and dry state were measured by photo‐correlation spectroscopy (PCS) and transmission electron microscopy (TEM), respectively. The morphology of swollen magnetic nanogels and that of polymer capsules obtained from magnetic nanogels etched by hydrochloride acid were observed by TEM. The high magnetizations and superparamagnetic behaviors of naked Fe₃O₄ and magnetic nanogels at room temperature were confirmed by the measurement of hysteresis curves. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1283–1290, 2006     

Interpolyelectrolyte complexes of maleic acid copolymers and chitosan for stabilization and functionalization of magnetite nano‐ and microparticles

A facile method of preparation of stabilized and functionalized nano‐ and microparticles of magnetite by successive application of oppositely charged polymers with a regular structure of macromolecular chains (chitosan and maleic acid copolymers) onto Fe₃O₄ core are developed. This approach makes it possible to create two types of magnetite interpolyelectrolyte shells, containing carboxylic or amino groups in outer layer of shell. Composition and magnetic properties of composite particles depend on nature of the copolymer of maleic acid, reaction conditions and size of obtained particles. The carboxylic groups of copolymer in outer layer of interpolyelectrolyte shell were converted into reactive anhydride groups by heating. Thermal treatment also leads to covalent crosslinking of shell and improves stability of composites both in acidic and alkaline media. Horseradish peroxidase was successfully immobilized onto covalently crosslinked and activated microparticles of Fe₃O₄ in aqueous medium without of condensing agents. The proposed reproducible and low‐cost technique does not use toxic reagents or solvents at all stages, including preparation of Fe₃O₄, formation, activation and crosslinking, of magnetite shell, modification of activated surface of composite particles. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39663.     

Synthesis of star–comb‐shaped polymer with porphyrin‐core and its self‐assembly behavior study

5,10,15,20‐tetra(4‐hydroxyphenyl)porphyrin (THPP) was synthesized by the condensation of pyrrole with 4‐hydroxybenzaldehyde in the presence of solvent (propionic acid). Subsequently, the resulting THPP was converted to a tetrafunctional star‐shaped macroinitiator (porphyrin‐Br₄) by esterification of it with 2‐bromopropanoyl bromide, and then atom transfer radical polymerization (ATRP) of styrene was conducted at 110°C with CuCl/2,2′‐bipyridine as the catalyst system. The resulting product was reacted with NBS to obtain star‐shaped initiator porphyrin‐(PSt‐Br)₄, which was used the following ATRP of the GMA to synthesize star–comb‐shaped grafted polymer porphyrin‐(PSt‐g‐PGMA)₄. The number molecular weight was 2.3 × 10⁴ g/mol, and the dispersity was narrow (M_w/M_n = 1.32). The structure of the polymers was investigated by NMR, UV–vis, IR, and GPC measurement. The self‐assembly behavior of the polymer porphyrin‐(PSt‐g‐PGMA)₄ was studied by DLS and AFM. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Yolk–shell structured iron carbide/N-doped carbon composite as highly efficient and stable oxygen reduction reaction electrocatalyst

We report a simple route to synthesize iron carbide/carbon yolk–shell composite via a facile two-step process including polymerization of pyrrole using Fe₃O₄ as a sacrificial template to form a Fe₃O₄/polypyrrole composite, followed by annealing at high temperature in N₂ atmosphere. The yolk–shell composite, with iron carbide (Fe_2.5C) embedded in nitrogen-doped carbon layers, shows impressively high catalytic activity and stability for oxygen reduction reaction in alkaline solution. Both the pyridinic-N and graphic-N in the shell of Fe₃O₄–PPy-700, together with the Fe_2.5C confined in carbon layers are believed to be the active sites for the ORR.     

Cr(III)‐containing Fe3O4/mercaptopropanoic acid‐poly(2‐hydroxyethyl acrylate) nanocomposite: Highly active magnetic catalyst for direct hydroxylation of benzene

In this study, polymer‐grafted magnetic nanoparticles containing chromium(III) ions incorporated onto Fe₃O₄/mercaptopropanoic acid‐poly(2‐hydroxyethyl acrylate) was prepared via a simple and in situ method. The obtained magnetic nanocomposite exhibited high catalytic activity and excellent selectivity in direct hydroxylation of benzene in the presence of hydrogen peroxide under solvent‐free condition. The magnetic catalyst could be also separated by an external magnet and reused seven times without any significant loss of activity/selectivity. Due to the Lewis acidity of the Fe³⁺ groups in the structure of magnetic nanoparticles, the high efficiency of this catalyst is possibly due to the synergetic effect of Cr³⁺ and Fe³⁺ groups in the structure of magnetic nanocomposite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40383.     

Efficient removal of Cu(II) using amino‐functionalized superparamagnetic nanoparticles prepared via SI‐ATRP

An amino‐functionalized nano‐adsorbent (DETA‐MNPs) was prepared by a process involving: (1) synthesis of superparamagnetic Fe₃O₄ nanoparticles; (2) introduction of amino groups after which ATRP initiator was anchored; (3) grafting of glycidyl methacrylate (GMA) via SI‐ATRP; and (4) ring‐opening reaction of epoxy groups with diethylenetriamine (DETA). The nano‐adsorbent was characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM) and applied to remove Cu(II) in batch experiments. The effects of pH, Cu(II) concentrations, solution ionic strength, and contact time were investigated. The results show that the DETA‐MNPs are spherical with cubic spine structure, high saturation magnetization (41.9 emu g^?1), and an average diameter of 10 nm. The maximum Cu(II) adsorption capacity achieves 83.33 mg g^?1 at pH 5.0 by Langmuir model. The adsorption process is highly pH‐dependent and reaches equilibrium within 20 min. Furthermore, the DETA‐MNPs exhibit excellent dispersibility and reusability. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 132, 42859.