Nickel Nanowires: Synthesis, Characterization and Application as Effective Catalysts for the Reduction of Nitroarenes (original) (raw)
Related papers
Molecular Catalysis, 2019
The one-pot stepwise reductive amination of arylaldehydes with nitroarenes is described, using reusable nickel nanoparticles (Ni-pol) as catalyst and NaBH 4 as mild, inexpensive, and safe reducing agent. The proposed catalytic system holds several advantages such as the use of a non-precious and earth-abundant metal, the facile separation of the catalyst from the reaction mixture by centrifugation, excellent stability towards air and moisture, very mild reaction conditions, good recyclability, broad substrate scope with good to excellent yields, and easy scalability (up to 1.0 g). FESEM analyses indicate that the active species are cubic nanocrystals of Ni in the average cross section value of 35 nm with a quite narrow (25-45 nm) and monomodal distribution, which becomes bimodal with the recycling reactions but without agglomeration.
Journal of Chemical Sciences, 2018
A novel resin-encapsulated nickel nanocatalyst has been synthesized by a modified impregnation method using nickel acetate tetrahydrate in presence of sodium borohydride as a mild reducing agent. The synthesized nanocatalyst was characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The concentration of nickel nanoparticles encapsulated on resin was determined by inductively coupled plasma-mass spectroscopy (ICP-MS). Further, synthesized resinencapsulated nickel nanocatalyst was found to be stable and efficient in micromolar concentrations, for the selective reduction of functionalized nitroarenes to corresponding amines in good to high yield, under mild reaction conditions. The nanocatalyst shows excellent reusability.
Molecular Catalysis, 2018
Polymer supported nickel nanoparticles, generated by calcination (N2 to 300 °C, 30 min) of a Ni(II) containing polyacrylamide, catalyzed the hydrogenation of nitroarenes to anilines in water at room temperature in the presence of NaBH4. The protocol generally favored the formation of the desired aniline as single product in high yields with short reaction times and proved to be highly selective in the hydrogenation of halonitrobenzene to haloaniline. The catalyst displayed excellent recyclability over fifth cycles and no leaching of metal into solution occurred, which made the overall system ecofriendly and economic. STEM analyses revealed that the thermally formed Ni nanoparticles turned into cubic nanotwins under reaction conditions, which remained almost unchanged with the recycles .
The catalytic reduction of nitroarenes under various catalytic systems has been widely reported in the flood of publications during last twenty years. This reaction has become a benchmark for testing catalytic activity of inorganic nanoparticles stabilized in various systems. This tutorial review presents design and classification of inorganic nanocatalysts along with their stabilizing agents used for catalytic reduction of nitroarenes. The techniques used for characterization of catalysts have been highlighted in this review. The mechanism of catalytic reduction has been described in a tutorial way. Factors affecting the rate of reduction of nitroarenes in the presence of metal nanoparticles stabilized in poly-electrolyte brushes, polyionic liquids, micelles, den-drimers, and microgels have been discussed for further development in this area.
Journal of colloid and interface science, 2018
Non-noble metal nanoclusters synthesis is receiving increased attention due to their unique catalytic properties and lower cost. Herein, the synthesis of ligand-free Ni nanoclusters with an average diameter of 0.7 nm corresponding to a structure of 13 atoms is presented; they exhibit a zero-valence state and a high stability toward oxidation and thermal treatment. The nanoclusters formation method consists in the electroreduction of nickel ions inside an ordered mesoporous alumina; also, by increasing the current density, other structures can be obtained reaching to nanowires of 10 nm diameter. A seed-mediated mechanism is proposed to explain the growth to nanowires inside these mesoporous cavities. The size dependence on the catalytic behavior of these entities is illustrated by studying the reduction of methylene blue where the nanoclusters show an outstanding performance.
Catalysis Communications, 2011
In this research, preparation of the magnetic nanoparticle, coating by a silica shell using (3-aminopropyl) triethoxysilane and synthesis of a novel sulfonic acid-substituted imidazolium-based ionic liquid onto the surface of these particles via a multi-component reaction, is described. The functionalized nanoparticles was loaded by Ni nanoparticles and characterized by means of techniques such as XRD, FTIR, SEM, EDX, TEM, TGA and ICP-OES. The nanostructures have spherical shapes that ranged in size from 80 to 100 nm. The catalytic activity of these nanoparticles was tested in aerobic oxidation of primary alcohols that showed good performance in the wide range of primary alcohols in water at mild reaction conditions. As a second step of this work, the tandem oxidative synthesis of alkylacrylonitriles and bisindolylmethanes were investigated using primary alcohols under oxidation conditions. This catalyst system can be recovered using external magnet and reused for five consecutive cycles without significantly less of its activity. Highlight • Synthesis a novel functionalized magnetic silica nanoparticles • Multi-component functionalization of the nanoparticles surfaces • Synthesis a sulfonated imidazolium-based ionic liquid • Oxidation of primary alcohols
The Synthesis and Use of Nano Nickel Catalysts
Journal of Nanoscience and Nanotechnology, 2019
The hydrazine reduction method was applied for the synthesis of nickel nanoparticles without using inert atmosphere and added surface active agents. The effect of the preparation temperature and the chemical quality of the metal sources as well as the solvents were studied. The generation of nanoparticles were studied primarily by X-ray diffractometry, but scanning and transmission electron microscopies as well as dynamic light scattering measurements were also used for the better understanding of the nanoparticles behaviour. The elevation of temperature was the key point in transforming Ni(OH) 2 into metallic nickel. By selecting the metal source, the obtained crystallite sizes could be tailored between 7 nm and 15 nm; however, the SEM and DLS measurements revealed significant agglomeration resulting in aggregates with spherical or Ni(OH) 2 resembling morphologies depending on the solvent used. The catalytic activities of the nanoparticles prepared were tested and compared in a Suzuki-Miyaura cross-coupling reaction.
Applied Catalysis A-general, 2011
Nickel nanowires (Ni NWs) were synthesized by the reducing action of hydrazine and stabilized by capping with l-methionine in aqueous solution. Characterization of the Ni NWs was carried out by UV–vis spectrometry, Fourier transform infra-red (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and X-ray diffractometry (XRD). Parameters like pH, concentration of reducing agent and molar ratio of Ni/l-methionine were found crucial for regulating the size of synthesized Ni NWs. The fabricated Ni NWs were employed as catalyst for catalytic oxidative dehydrogenation (transfer hydrogenation) of isopropanol (IPA) to acetone using aqueous medium in the presence of sodium borohydride (NaBH4) as hydrogen source. The effect of parameters studied during transfer hydrogenation of IPA included the concentration of IPA, concentration of NaBH4, time of reaction and amount of Ni NWs. The study revealed that IPA could be transformed into acetone with 100% yield in only 1 min time of reaction. The catalyst was easy to recover and capable to be reused several times. The study shows that the catalytic transformation of IPA into acetone by synthesized Ni NWS in aqueous medium is environmental friendly in terms of recovery of catalyst, very fast and hence extremely economical.► Simple method was investigated for the fabrication of nickel nanowires (Ni NWs). ► l-methionine acted as capping as well as stabilizing agent for Ni NWs. ► Formed Ni NWs proved as catalysts for 100% conversion of isopropanol to acetone.
Selective Reduction of Nitroarenes with Silanes Catalyzed by Nickel N-Heterocyclic Carbene Complexes
ChemCatChem, 2017
An efficient catalytic system for the reduction of nitroarenes to amines was developed using a well-defined nickel-NHC complex as catalyst and phenylsilane as reducing agent. The excellent activity of the catalyst provides access to anilines containing a wide array of reactive functionalities at 20 °C, and without using any base or additive. Notably, the catalytic system allows the reduction of 5,10,15,20-tetra-(nitrophenyl)porphyrin (TNPP) and Cu(II) -nitroporphyrin to the corresponding aminoporphyrins.