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CHEMISTRY (594 journals)            First | 1 2 3 4 5 6 | Last

Journal of Analytical Methods in Chemistry     Open Access  
Journal of Analytical Sciences, Methods and Instrumentation     Open Access   (Followers: 2)
Journal of AOAC International     Full-text available via subscription   (Followers: 9)
Journal of Applied Chemistry     Open Access   (Followers: 4)
Journal of Applied Solution Chemistry and Modeling     Hybrid Journal  
Journal of Applied Spectroscopy     Hybrid Journal   (Followers: 8)
Journal of Argentine Chemical Society     Open Access  
Journal of Biomaterials and Nanobiotechnology     Open Access   (Followers: 6)
Journal of Carbohydrate Chemistry     Hybrid Journal   (Followers: 5)
Journal of Catalysis     Hybrid Journal   (Followers: 8)
Journal of Catalyst & Catalysis     Full-text available via subscription   (Followers: 1)
Journal of Catalysts     Open Access  
Journal of Chemical & Engineering Data     Full-text available via subscription   (Followers: 10)
Journal of Chemical and Biological Interfaces     Full-text available via subscription   (Followers: 1)
Journal of Chemical Education     Full-text available via subscription   (Followers: 21)
Journal of Chemical Health Risks     Open Access   (Followers: 2)
Journal of Chemical Information and Modeling     Full-text available via subscription   (Followers: 6)
Journal of Chemical Research     Full-text available via subscription   (Followers: 6)
Journal of Chemical Science and Technology     Open Access   (Followers: 3)
Journal of Chemical Sciences     Partially Free   (Followers: 17)
Journal of Chemical Theory and Computation     Full-text available via subscription   (Followers: 14)
Journal of Chemical Thermodynamics     Hybrid Journal   (Followers: 4)
Journal of Cheminformatics     Open Access   (Followers: 2)
Journal of Chemistry     Open Access   (Followers: 5)
Journal of Chemometrics     Hybrid Journal   (Followers: 10)
Journal of Chromatography A     Hybrid Journal   (Followers: 60)
Journal of Clinical Toxicology     Open Access   (Followers: 2)
Journal of Colloid and Interface Science     Hybrid Journal   (Followers: 14)
Journal of Computational Chemistry     Hybrid Journal   (Followers: 17)
Journal of Coordination Chemistry     Hybrid Journal   (Followers: 3)
Journal of Dispersion Science and Technology     Hybrid Journal  
Journal of Encapsulation and Adsorption Sciences     Open Access   (Followers: 4)
Journal of Environmental Chemistry and Ecotoxicology     Open Access   (Followers: 2)
Journal of Flow Chemistry     Full-text available via subscription   (Followers: 1)
Journal of Fluorescence     Hybrid Journal   (Followers: 5)
Journal of Fluorine Chemistry     Hybrid Journal   (Followers: 6)
Journal of Fuel Chemistry and Technology     Full-text available via subscription   (Followers: 5)
Journal of Great Lakes Research     Hybrid Journal   (Followers: 7)
Journal of Heterocyclic Chemistry     Hybrid Journal   (Followers: 5)
Journal of Immunoassay and Immunochemistry     Hybrid Journal   (Followers: 6)
Journal of Inclusion Phenomena and Macrocyclic Chemistry     Hybrid Journal   (Followers: 2)
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 2)
Journal of Labelled Compounds and Radiopharmaceuticals     Hybrid Journal   (Followers: 1)
Journal of Macromolecular Science, Part A: Pure and Applied Chemistry     Hybrid Journal   (Followers: 3)
Journal of Mass Spectrometry     Hybrid Journal   (Followers: 27)
Journal of Materials Chemistry A : Materials for Energy and Sustainability     Full-text available via subscription   (Followers: 27)
Journal of Materials Chemistry B : Materials for Biology and Medicine     Full-text available via subscription   (Followers: 6)
Journal of Materials Chemistry C : Materials for Optical, Magnetic and Electronic Devices     Full-text available via subscription   (Followers: 9)
Journal of Materials Physics and Chemistry     Open Access   (Followers: 1)
Journal of Materials Research     Full-text available via subscription   (Followers: 10)
Journal of Mathematical Chemistry     Hybrid Journal   (Followers: 6)
Journal of Medicinal Chemistry     Full-text available via subscription   (Followers: 74)
Journal of Membrane and Separation Technology     Hybrid Journal   (Followers: 1)
Journal of Membrane Science     Hybrid Journal   (Followers: 14)
Journal of Metastable and Nanocrystalline Materials     Full-text available via subscription  
Journal of Modern Chemistry & Chemical Technology     Full-text available via subscription   (Followers: 2)
Journal of Molecular Catalysis A: Chemical     Hybrid Journal   (Followers: 4)
Journal of Molecular Graphics and Modelling     Hybrid Journal   (Followers: 4)
Journal of Molecular Liquids     Hybrid Journal   (Followers: 1)
Journal of Molecular Modeling     Hybrid Journal   (Followers: 4)
Journal of Molecular Recognition     Hybrid Journal   (Followers: 2)
Journal of Molecular Spectroscopy     Hybrid Journal   (Followers: 7)
Journal of Molecular Structure     Hybrid Journal   (Followers: 3)
Journal of Nanoparticles     Open Access  
Journal of Nanostructure in Chemistry     Open Access   (Followers: 3)
Journal of Natural Gas Chemistry     Full-text available via subscription   (Followers: 2)
Journal of Nepal Chemical Society     Open Access  
Journal of Nucleic Acids Investigation     Open Access   (Followers: 2)
Journal of Ocean University of China (English Edition)     Hybrid Journal  
Journal of Organometallic Chemistry     Hybrid Journal   (Followers: 15)
Journal of Photochemistry and Photobiology A: Chemistry     Hybrid Journal   (Followers: 4)
Journal of Photochemistry and Photobiology C: Photochemistry Reviews     Full-text available via subscription   (Followers: 3)
Journal of Polymer & Composites     Full-text available via subscription   (Followers: 7)
Journal of Polymer and Biopolymer Physics Chemistry     Open Access   (Followers: 3)
Journal of Polymer Science Part A: Polymer Chemistry     Hybrid Journal   (Followers: 110)
Journal of Polymers     Open Access   (Followers: 3)
Journal of Porphyrins and Phthalocyanines     Hybrid Journal   (Followers: 2)
Journal of Pure and Applied Chemistry Research     Open Access   (Followers: 1)
Journal of Raman Spectroscopy     Hybrid Journal   (Followers: 12)
Journal of Research Updates in Polymer Science     Hybrid Journal  
Journal of Saudi Chemical Society     Open Access  
Journal of Solid State Chemistry     Hybrid Journal   (Followers: 15)
Journal of Solution Chemistry     Hybrid Journal   (Followers: 3)
Journal of Structural Chemistry     Hybrid Journal  
Journal of Sulfur Chemistry     Hybrid Journal   (Followers: 2)
Journal of Superhard Materials     Hybrid Journal   (Followers: 1)
Journal of Surfactants and Detergents     Hybrid Journal   (Followers: 4)
Journal of Taibah University for Science     Open Access   (Followers: 1)
Journal of the American Chemical Society     Full-text available via subscription   (Followers: 217)
Journal of the American Society for Mass Spectrometry     Hybrid Journal   (Followers: 21)
Journal of the American Society of Brewing Chemists     Full-text available via subscription   (Followers: 1)
Journal of the Bangladesh Chemical Society     Open Access  
Journal of the Chilean Chemical Society     Open Access   (Followers: 2)
Journal of the Iranian Chemical Society     Hybrid Journal  
Journal of the Korean Society for Applied Biological Chemistry     Hybrid Journal   (Followers: 1)
Journal of the Mexican Chemical Society     Open Access   (Followers: 1)
Journal of Theoretical and Computational Chemistry     Hybrid Journal   (Followers: 9)
Journal of Theoretical Chemistry     Open Access  
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 7)
JPC - Journal of Planar Chromatography - Modern TLC     Full-text available via subscription   (Followers: 5)

  First | 1 2 3 4 5 6 | Last

Journal Cover Kinetics and Catalysis
  [SJR: 0.367]   [H-I: 21]   [3 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1608-3210 - ISSN (Online) 0023-1584
   Published by Springer-Verlag Homepage  [2280 journals]
  • Synthesis and structural studies of polymer-supported transition metal
           complexes: Efficient catalysts for oxidation of phenol
    • Abstract: Abstract In this work, a new simple and reproducible method for preparation of a series of novel recyclable complexes is described. The series includes unsupported 3-MHBdMBn–Met complexes (Met = iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) ions), and polystyrene anchored (P-3-MHBdMBn–Met) metal ion complexes, supported by—ONNO-tetradentate Schiff-base ligand. These free and polymer anchored metal complexes are prepared by the reactions of metal solution with one molar equivalent of unsupported 3-MHBdMBn (N,N'-bis(2-hydroxy-3-methylbenzaldehyde)-4-methylbenzene-1,2-diamine) or polymer-supported (P-3-MHBdMBn) Schiff-base ligands in methanol under nitrogen atmosphere. The greatest advantage of this catalyst system over other polymer-supported catalysts is a remarkably low cost and the quality of being recycled up to six times. These benefits are due to the easily accessible materials and the simple synthetic route. A higher efficiency of complexation of metal ions on the polymer anchored 3-MHBdMBn Schiff base compared to that shown by an unsupported analogue is another advantages of this catalyst system. The structural study reveals that iron(III) complex is octahedral in geometry, whereas cobalt(Il), nickel(II) and copper(II) complexes are square planar and zinc(II) complex is of tetrahedral geometry. The catalytic activities of polystyrene-supported metal complexes toward the oxidation of phenol are investigated. Experimental results indicate that the reactivity of P-3-MHBdMBn–Met is dramatically affected by the polymer support and iron complexes are more active than other complexes. The rate of phenol conversion is high (2.41 × 10–6 mol dm–3 s–1) in the presence of polystyrene-supported 3-MHBdMBn Schiff base complexes of iron(III) ions and low in the presence of zinc(II) analogue (1.36 × 10–6 mol dm–3 s–1).
      PubDate: 2015-11-01
  • Size effect of Pd nanoparticles in the selective liquid-phase
           hydrogenation of diphenylacetylene
    • Abstract: Abstract The liquid-phase hydrogenation of diphenylacetylene over Pd catalysts supported on Al2O3 with different specific surface areas has been investigated. A decrease in the specific surface area of the support leads to a marked increase in the selectivity of the reaction. The observed increase in the selectivity is due to the increase in the size of Pd0 nanoparticles. As a result, the specific rate of triple bond hydrogenation increases over the rate of the undesired hydrogenation of the olefinic intermediate and the efficiency of kinetic control over the selectivity of the overall process is enhanced.
      PubDate: 2015-11-01
  • La 1–x Ca x FeO 3–δ ( x = 0–1) perovskites prepared
           by the Pechini method: Catalytic activity in deep methane and CO oxidation
    • Abstract: Abstract The catalytic activity of a series of La1–x Ca x FeO3–δ (x = 0–1) materials prepared by the Pechini method from polymer–salt stocks has been investigated, and the phase composition and microstructure of these materials before and after testing them in methane oxidation have been determined. The activity and stability of the materials depends on their composition and on the reaction temperature. The introduction of calcium into lanthanum ferrite up to x = 0.5 causes a nonmonotonic increase in the activity of the catalyst in methane oxidation. As x is further increased, the catalytic activity falls off. It has been analyzed how the activity of the catalysts is affected by variations of their imperfection and microstructure as a result of the introduction of calcium and under the action of the reaction medium. According to high-resolution transmission electron microscopy data, under the action of the reaction medium the perovskite structure undergoes partial degradation (in subsurface layers) leading to the formation of planar defects and to the release of iron oxide nanoparticles.
      PubDate: 2015-11-01
  • Effect of zirconia additives on the activity of the Cr/SiO 2 catalyst in
           isobutane dehydrogenation
    • Abstract: Abstract A new approach to the preparation of modified silica-based supports is suggested to obtain Crcontaining catalysts for paraffin hydrocarbon dehydrogenation. CrO x /ZrO2, CrO x /SiO2, and CrO x /nZrO2–SiO2 (n = 0.5, 1.0, and 2.0 ZrO2 monolayers) catalysts have been synthesized by incipient-wetness impregnation. The catalysts have been characterized by X-ray diffraction, diffuse reflectance spectroscopy, and temperature-programmed reduction with hydrogen. Their catalytic properties were investigated in the reaction of isobutane dehydrogenation. The state of the supported chromium depends considerably on the nature of the support. The formation of Cr2O3 particles, which show low activity in the dehydrogenation reaction, takes place in the CrO x /SiO2 catalyst, while chromium in the CrO x /ZrO2 catalyst is in a highly dispersed, X-ray-amorphous state. The addition of ZrO2 to CrO x /SiO2 increases the amount of chromium in the highly dispersed Cr(V) and Cr(VI) states, thus enhancing the isobutane dehydrogenation activity of the catalyst.
      PubDate: 2015-11-01
  • XPS study of gold oxidation with nitrogen dioxide in model Au/C samples
    • Abstract: Abstract The interaction of NO2 with model samples obtained by the gold sputter deposition onto the surface of highly oriented pyrolytic graphite (HOPG) has been studied by X-ray photoelectron spectroscopy (XPS). It has been shown that 3D metal particles characterized by an Au4f 7/2 binding energy (BE) of 84.0 eV form on the initial smooth graphite surface. During the sputter deposition onto the surface of HOPG preliminarily activated by means of ion etching, gold atoms chemically bound to the carbon atoms form in the area of surface defects. Such atoms are characterized by a positive shift of BE(Au4f 7/2). It has been established that the 3D particles are resistant to the action of NO2 under the pressure XXXXXXXX mbar at room temperature. On the contrary, atomic gold oxidizes under these conditions into Au(III) complexes bound to the graphite surface. It is assumed that gold atoms on the support surface play the role of active sites of gold catalysts in oxidation reactions.
      PubDate: 2015-11-01
  • Enhanced catalytic performance of Co–Sn composite oxide in styrene
           epoxidation with air
    • Abstract: Abstract A simple calcination process was used to obtain Co–Sn composite oxides, the structure of which was confirmed by the XRD analysis. For comparison, the pure cobalt oxide was also prepared under the same calcination condition. According to TEM measurements, the composite oxide prepared in the presence of Sn had lower particle size than pure cobalt oxide. Accordingly, the presence of Sn increased the specific surface area as evidenced by the BET analysis data. The as-prepared Co–Sn composite oxides were applied as heterogeneous catalysts in the epoxidation of styrene with air and exhibited catalytic activity with 77.9 mol % of styrene converted and 87.1% selectivity for epoxide. These results exceed those obtained for pure cobalt oxide. However, the addition of ions of other metals such as Fe, Ni, Cu, Zn and Mn to the catalyst had a detrimental effect on the styrene epoxidation. The mechanistic considerations are also presented and suggestion is given that the DMF solvent plays a key role in the catalytic epoxidation. Results of the study indicate that Co–Sn composite oxides are efficient heterogeneous catalysts for the epoxidation of styrene with air in DMF.
      PubDate: 2015-11-01
  • Mn–Ce/beta “bifunctional” catalyst for the selective
           catalytic reduction of nitrogen oxides with ammonia
    • Abstract: Abstract The properties of the Mn–Ce/Beta zeolite catalyst in the selective catalytic reduction (SCR) of NO x have been investigated. The introduction of Ce leads to a marked increase in the NO x conversion at 100–250°C. The data of this study are consistent with the “bifunctional” pathway of SCR suggested for Mn/Beta, which consists of two stages—NO oxidation to NO2 over the oxide component and “fast” SCR over the zeolite. The increased activity of Mn–Ce/Beta at the NO-to-NO2 oxidation stage is due to the formation of MnCeO x mixed oxides enhancing the mobility of lattice oxygen. The determining role is played by the activity of the zeolite component in the “fast” SCR reaction.
      PubDate: 2015-11-01
  • Structural features of promoted MoVTeNbO catalysts for the oxidative
           dehydrogenation of ethane
    • Abstract: Abstract The morphology, crystal structure, and phase composition of MoVTeNbO catalysts modified with K, Ca, Zr, or Bi were studied, and the effects of promoters on their catalytic properties in the oxidative conversion reaction of ethane were examined. With the use of high-resolution transmission electron microscopy (HRTEM), it was found that Bi and K were inserted into the structure of the active phase M1 and potassium changed its morphology. Zr and Ca formed individual oxides and molybdates. Changes in the structure of the promoted models affected their catalytic properties.
      PubDate: 2015-11-01
  • Size effect in the oxidation–reduction processes of platinum
           particles supported onto silicon dioxide
    • Abstract: Abstract The interaction of the Pt/SiO2 model catalysts as thin films on the surface of tantalum supports with a mixture of NO + O2 (1: 1) was studied by X-ray photoelectron spectroscopy. The pressure of the reaction mixture was varied from 6 to 64 mbar, and the temperature was varied from room temperature to 500°C. Two types of the catalysts, in which the Pt/Si atomic ratios were ~0.1 and ~0.3 (0.1-Pt/SiO2 and 0.3-Pt/SiO2, respectively) according to the XPS data, were studied. In 0.1-Pt/SiO2, the particles of platinum predominantly had a size from 1 to 2.5 nm; a wide Pt particle size distribution in a range from 1 to 15 nm with a maximum at ~4 nm was characteristic of 0.3-Pt/SiO2. The interaction of all of the samples with NO + O2 at room temperature led to the dissolution of oxygen atoms in the bulk of platinum metal particles. As the reaction temperature was increased, PtO x platinum oxide particles were formed: from small Pt particles in 0.1-Pt/SiO2 at 300°C and from larger particles in 0.3-Pt/SiO2 at 400–500°C. It was established that the reactivity of platinum oxide particles toward hydrogen also depended on the particle size. The small particles of platinum oxide were converted into platinum metal under the action of hydrogen (16 mbar) at 300°C. The coarse particles of PtO x in the samples of 0.3-Pt/SiO2 were reduced much more easily starting with room temperature.
      PubDate: 2015-11-01
  • Mechanism of carbon monoxide oxidation on supported copper catalysts
           modified with cerium and platinum
    • Abstract: Abstract The mechanism of CO oxidation on copper oxide catalysts without additives and with cerium and platinum additives supported on γ-Al2O3 was studied. It was found that the presence of Ce and Pt facilitated the reduction of copper and increased the activity of the catalysts. It was established that the parent substances participated in the reaction from an adsorbed state; in this case, the surface coverage of all of the catalysts with oxygen was greater than the coverage with CO, and the reaction system components exhibited different adsorption capacity. The introduction of Ce increases the bond strength of CO with the surface and weakens the bond of oxygen with the surface. The presence of Pt increases the bond strengths of CO, O2, and CO2 with the surface.
      PubDate: 2015-11-01
  • Development of a macro-micro kinetic model for CO hydrogenation over
           Co–Ni catalyst
    • Abstract: Abstract A novel approach in kinetic study of CO hydrogenation reaction over Co–Ni/Al2O3 catalyst was described. The experimental data were collected using a fixed bed micro reactor under next conditions: pressure 2–12 bar, temperature 230–280°C, molar ratio H2: CO = 1–3, space velocity 2000–2700 h–1. A new Langmiur–Hinshelwood (LH) kinetic model on the basis of formyl mechanism was developed. The apparent activation energy of LH kinetic model, bond energy of carbon, oxygen, hydrogen and some surface intermediate on catalyst surface, activation energies of some surface reactions and catalyst surface coverage were estimated from a new combined LHHW/UPI–QEP methodology. It was postulated that under reaction conditions used, CH2 formation through H-assisted CO dissociation is probably dominant mechanism of hydro-genation over Co–Ni catalyst.
      PubDate: 2015-11-01
  • Pd(AcO) 2 supported by 1,3,5-triazine functionalized nanoporous polymers:
           Efficient and recyclable heterogeneous catalysts for Suzuki–Miyaura
    • Abstract: Abstract 1,3,5-Triazine functionalized nanoporous polymer (PDVB-triazine-xs, where x stands for the molar ratio of DVB and triazine) was synthesized from copolymerization of 1,3,5-triacryloylhexahydro1,3,5-triazine with divinylbenzene (DVB) cross-linker under solvothermal conditions. The resultant PDVB-triazine-xs act as efficient supports for Pd(OAc)2, which gives the Pd/PDVB-triazine-xs catalyst. Characterizations by N2 isotherms, TEM images, and solid NMR 13C spectrum show that Pd/PDVB-triazine-xs has large surface areas, abundant nanopores, and successful copolymerization of DVB with triazine functional monomer, which showed a high cross linking degree. XRD and elemental maps show Pd was successfully loaded into PDVB-triazine-xs supports, which showed very good dispersion in the samples. Pd/PDVB-triazine-xs showed excellent catalytic activity and good recyclability in Suzuki–Miyaura cross coupling reaction. The preparation of Pd/PDVB-triazine-xs will develop functional nanoporous polymer based catalysts or catalyst supports in the Suzuki–Miyaura reaction.
      PubDate: 2015-11-01
  • Effect of iron oxide additives on the physicochemical and catalytic
           properties of the supported Pt/TiO 2 catalysts in the oxidation of carbon
    • Abstract: Abstract The effect of iron oxide additives on the formation of the microstructure, the electronic state, and the catalytic properties of supported Pt/TiO2 catalysts in the reaction of CO oxidation was studied. It was established that the microstructure of the catalyst changed upon the introduction of iron additives and activity in the oxidation of CO increased. The increase in the catalytic activity was explained by a decrease in the particle size of supported platinum and by an increased contribution from the Ptδ+ state. The optimum chemical composition of the catalyst, which ensured the highest catalyst activity in the reaction of CO oxidation, was determined.
      PubDate: 2015-11-01
  • Preparation of platinum-containing hydrogenation catalysts supported on
           thermally reduced graphite oxide
    • Abstract: Abstract Graphene-like materials with an atomic ratio of C/O > 40 have been prepared by calcination of graphite oxide (C/O = 1.46) in an inert atmosphere. Platinum nanoparticles (average size of ~2.0 nm) have been deposited onto the surface of the materials from an aqueous solution of H2PtCl6 · xH2O in the presence of pyridine. These particles catalyze the liquid-phase hydrogenation of PhNO2 to PhNH2 and that of the double bonds in 1-decene and styrene. As a support, the defect-containing graphene-like material prepared by calcination of graphite oxide at 1000–1050°C for 3 h has certain advantages over graphite oxide reduced by chemical means or by short-term heating. This material and catalysts supported on it can be formed as “carbon paper” by vacuum filtration.
      PubDate: 2015-11-01
  • Selective hydrotreating of cat-cracked gasoline over a K–CoMoS/Al 2
           O 3 catalyst
    • Abstract: Abstract The catalytic properties of CoMoS/Al2O3 and K–CoMoS/Al2O3 laboratory catalysts versus those of the commercial catalyst NK-100 (CoMo/Al2O3) have been investigated in the hydrotreating of the heavy fraction of cat-cracked gasoline (CCG). The basic kinetic parameters of the hydrodesulfurization and olefin hydrogenation processes have been experimentally determined. The addition of 7.5 wt % potassium to the CoMoS/Al2O3 catalyst decreases both the apparent activation energy and preexponential factor of both processes and increases the selectivity coefficient by a factor of over 3. Selective hydrotreating of the heavy fraction of CCG has been carried out over a K–CoMoS/Al2O3 sample at a temperature of 280°C, a pressure of 1.5MPa, a feed hourly space velocity of 7.5 h–1, and H2: feed = 100 NL/L. As a result, the sulfur content of gasoline has been reduced from 92 to 13 mg/kg without affecting the octane number. If the proportion of CCG in commercial gasoline obtained by compounding CCG with other components is 20–35%, the sulfur content of the product will meet the environmental requirements imposed on Class 5 fuels according to regulations.
      PubDate: 2015-11-01
  • Chlorobenzene hydrodechlorination catalyst prepared via the pyrolysis of
           sawdust impregnated with palladium nitrate
    • Abstract: Abstract (7% Pd)/C catalysts have been prepared by the pyrolysis of untreated sawdust and sawdust washed with an acid to remove of Group I and II metal impurities, both impregnated with palladium nitrate. Studies by transmission electron microscopy, X-ray photoelectron spectroscopy, and temperature-programmed reduction have demonstrated that the dominant palladium species in the catalysts is 2–5 nm Pd0 particles, there is no PdO on the surface, and the catalyst bulk contains small amounts of larger (10–20 nm) PdO particles. The catalysts are active in chlorobenzene hydrodechlorination in a fixed-bed flow reactor and ensure 100% conversion of the substrate into benzene in the temperature range from 250 to 350°C. At lower temperatures (150–200°C), the catalyst containing calcium is the most active and the sample subjected to reduction after pyrolysis shows the lowest activity.
      PubDate: 2015-11-01
  • Selective catalytic reduction of NO over M–Ag/ZSM-5 bimetallic
           nanocatalysts (M = Mn, Fe and Ni). Physicochemical properties and
           catalytic performance
    • Abstract: Abstract Selective catalytic reduction of NO by ammonia in the presence of excess oxygen has been studied over monometallic Ag/ZSM-5 and bimetallic M–Ag/ZSM-5 (M = Mn, Fe and Ni) nanocatalysts. Ag/ZSM-5 shows a good activity but low selectivity to N2 and produces N2O in considerable amounts. To improve selectivity for N2 the Ag/ZSM-5 catalyst was modified by adding different transition metals (Mn, Fe and Ni). The Fe–Ag/ZSM-5 bimetallic nanocatalyst showed the highest activity (95% NO conversion and 73% selectivity to N2 at 300°C). X-ray diffraction, transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), ammonia temperature-programmed desorption (NH3-TPD), and X-ray photoelectron spectroscopy were applied to characterize Ag/ZSM5 and M–Ag/ZSM-5 nanocatalysts. TEM results revealed the presence of nano-sized Ag/metal oxide species on the H-ZSM-5 support in M–Ag/ZSM-5 catalysts and highly dispersed Ag/metal oxide species in the Fe–Ag/ZSM-5 catalyst. The NH3-TPD measurements confirmed that compared to other catalysts the Fe–Ag/ZSM-5 catalyst has an increased amount of strong acid sites and a higher NH3 storage capacity.
      PubDate: 2015-09-01
  • CO 2 hydrogenation over cobalt-containing catalysts
    • Abstract: Abstract Carbon dioxide hydrogenation over catalysts consisting of 0.56–45 wt % cobalt supported on carbon nanotubes (CNTs), carbon nanofibers, few-layer graphite fragments, or CNTs–Al2O3 composites has been investigated. All of the Co/support catalytic systems have been characterized by temperature-programmed reduction, transmission electron microscopy, and scanning electron microscopy. Under the conditions of our catalytic experiment (1 atm, 180–500°C), the CO2 hydrogenation products are CH4 and/or CO and the activity of the catalysts depends on the size and phase state of the cobalt particles. The CNTs-supported materials containing less than 5 wt % Co are catalytically inactive because of the amorphism of the metal. They can be activated by cobalt crystallization by means of heat treatment. The size of the cobalt particles deposited on the carbon supports is about 4 nm. Methods of functionalizing the carbon nanomaterial surface for additional stabilization of metal nanoparticles are suggested.
      PubDate: 2015-09-01
  • Synthesis of membrane catalysts based on Mo 2 C
    • Abstract: Abstract Versions of the synthesis of composite membrane catalysts based on Mo2C and ceramic microfiltration membranes by chemical vapor deposition and a sol–gel method were developed. The samples of massive and supported membrane catalysts were prepared. Differences in the formation of a catalytic layer and its porous structure depending on the sample preparation method were demonstrated. The catalytic activity of the synthesized samples in the carbon dioxide conversion reaction of methane was studied.
      PubDate: 2015-09-01
  • Kinetics, mechanism, and mathematical model of the reaction between uracil
           and hydrogen peroxide in aqueous solution
    • Abstract: Abstract The kinetics and mechanism of the reaction between uracil and hydrogen peroxide in aqueous solution have been investigated. Iron ion admixtures in the solution have been demonstrated to bring about two reaction pathways, one free-radical and the other molecular. The mechanism of the reaction has been analyzed by mathematical modeling methods, kinetic curves illustrating the variation of intermediate product concentrations have been obtained, and the rate constants of elementary reactions have been calculated.
      PubDate: 2015-09-01
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