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Total 23 records

    Supported cobalt oxide nanoparticles as efficient catalyst in esterification and amidation reactions

    , Article Catalysis Communications ; Volume 59 , January , 2014 , Pages 122-126 ; 15667367 (ISSN) Rajabi, F ; Raessi, M ; Arancon, R. A. D ; Saidi, M. R ; Luque, R ; Sharif University of Technology
    Elsevier  2014
    Abstract
    Co/SBA-15 nanoparticle catalysts (CoNP) were prepared using a commonly adapted synthetic route and then utilised for esterification and amidation reactions using aromatic and linear chain compounds for the production of long chain esters and amides. The study shows that the use of CoNP catalysts favours the use of aromatic reactants with electron donating substituents specifically in the para position. For the amidation reaction, good to excellent yields were obtained demonstrating tolerance towards differently substituted aromatic compounds. Overall, the synthesized catalysts proved to be efficient and highly versatile, and recyclable under the investigated conditions  

    Preparation and study of bi-supported Ziegler-Natta catalyst with nano graphene oxide and magnesium ethoxide supports for polymerization of polyethylene

    , Article Polymer Science - Series B ; Volume 58, Issue 3 , 2016 , Pages 271-277 ; 15600904 (ISSN) Kheradmand, A ; Ramazani SaadatAbadi, A ; Khorasheh, F ; Baghalha, M ; Bahrami, H ; Sharif University of Technology
    Maik Nauka-Interperiodica Publishing  2016
    Abstract
    In this study, we have reported the preparation of bi-supported Ziegler-Natta catalysts using magnesium ethoxide and graphene oxide as support. The polymerization process was carried out in slurry phase using triisobutylaluminum as a co-catalyst.The XRD analysis of TiCl4/graphene oxide/Mg(OEt)2 catalyst demonstrated that the space between the layers of graphene oxide had increased to 0.2 nm.The catalyst was characterized by XPS, BET, BJH, SEM, and TGA. The catalyst activity was studied for various Al/Ti molar ratios, and the catalyst activity was optimum at Al/Ti molar ratio of 315. © 2016, Pleiades Publishing, Ltd  

    Hydro-purification of crude terephthalic acid using palladium catalyst supported on multi-wall carbon nanotubes

    , Article Journal of Industrial and Engineering Chemistry ; 2015 ; ISSN: 1226086X Tourani, S ; Khorasheh, F ; Rashidi, A. M ; Safekordi, A. A ; Sharif University of Technology
    Abstract
    Palladium catalysts supported on functionalized multi-wall carbon nanotubes were synthesized for hydro-purification of crude terephthalic acid containing 2100ppm 4-carboxybenzaldehyde (4-CBA) as impurity. PdCl2 and Pd(OAc)2 were used as precursors. Palladium loadings were 0.05 to 0.6wt.% with catalysts reduced at 200 to 400°C. Catalysts prepared from both precursors with least 0.3wt.% palladium resulted in 99%+ removal of 4-CBA. The most desired selectivity was obtained for the catalyst with PdCl2 as precursor, reduction temperature of 300°C, and palladium loading of 0.3wt.%. This catalyst had slightly better performance than the commercial catalyst (0.5wt.% of palladium on activated carbon)... 

    Studies on the catalyst preparation methods and kinetic behavior of supported cobalt catalysts for the complete oxidation of cyclohexane

    , Article Reaction Kinetics, Mechanisms and Catalysis ; Volume 114, Issue 2 , Jan , 2015 , Pages 611-628 ; 18785190 (ISSN) Zabihi, M ; Khorasheh, F ; Shayegan, J ; Sharif University of Technology
    Springer Netherlands  2015
    Abstract
    Low cost dispersed supported cobalt oxide nanocatalysts on activated carbon (AC) were prepared by two different methods: (1) combined impregnation and deposition–precipitation (IMP-DP) and (2) heterogeneous deposition–precipitation (HDP). XRD, TEM, FESEM, BET and Boehm techniques were used for the characterization of the support and the catalysts. Characterization analyses indicated the negative effect of the wet impregnation method on the IMP-DP technique for the preparation of catalysts for the total oxidation of cyclohexane in air. The catalysts prepared by HDP and IMP-DP methods were found to have significant differences in oxidation activity, morphology, particle size, and shape of... 

    Hydro-purification of crude terephthalic acid using palladium catalyst supported on multi-wall carbon nanotubes

    , Article Journal of Industrial and Engineering Chemistry ; Volume 28 , August , 2015 , Pages 202-210 ; 1226086X (ISSN) Tourani, S ; Khorasheh, F ; Rashidi, A. M ; Safekordi, A. A ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2015
    Abstract
    Palladium catalysts supported on functionalized multi-wall carbon nanotubes were synthesized for hydro-purification of crude terephthalic acid containing 2100ppm 4-carboxybenzaldehyde (4-CBA) as impurity. PdCl2 and Pd(OAc)2 were used as precursors. Palladium loadings were 0.05 to 0.6wt.% with catalysts reduced at 200 to 400°C. Catalysts prepared from both precursors with least 0.3wt.% palladium resulted in 99%+ removal of 4-CBA. The most desired selectivity was obtained for the catalyst with PdCl2 as precursor, reduction temperature of 300°C, and palladium loading of 0.3wt.%. This catalyst had slightly better performance than the commercial catalyst (0.5wt.%... 

    Factors affecting platinum extraction from used reforming catalysts in iodine solutions at temperatures up to 95 °C

    , Article Hydrometallurgy ; Volume 97, Issue 1-2 , 2009 , Pages 119-125 ; 0304386X (ISSN) Zanjani, A ; Baghalha, M ; Sharif University of Technology
    2009
    Abstract
    Platinum extraction from the spent reforming catalysts in iodine-iodide solutions at temperatures from 25 to 95 °C was investigated. The reforming catalyst mostly consists of a porous gamma alumina support with metallic platinum finely dispersed on the walls of the nano-pores of the catalyst support. The effect of a variety of factors, including catalyst particle size, impeller agitation speed, reactant concentrations, liquid to solid mass ratio, temperature and the solution pH on the Pt extraction rate and recovery were investigated. It was found that the catalyst particle sizes less than 106 μm and impeller agitation speed higher than 700 rpm eliminated the effects of catalyst size and... 

    Mesoporous nanostructured Ni/MgAl2O4 catalysts: Highly active and stable catalysts for syngas production in combined dry reforming and partial oxidation

    , Article International Journal of Hydrogen Energy ; Volume 44, Issue 21 , 2019 , Pages 10427-10442 ; 03603199 (ISSN) Jalali, R ; Nematollahi, B ; Rezaei, M ; Baghalha, M ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    In this paper, the combination of dry reforming and partial oxidation of methane on nickel catalysts supported on mesoporous MgAl2O4 was investigated. The support was prepared by a facile sol-gel route using propylene oxide as a gelation agent. The characterizations of the catalysts were performed by BET, XRD, TPR, TPO, TPH, UV–vis, CO-dispersion, SEM and TEM techniques. In addition, the effects of nickel content, reaction and reduction temperatures, feed ratio and the GHSV value on the physicochemical and catalytic properties were studied. The results revealed that the nickel content had an optimum value of 7.5 wt% and the catalyst with this content of nickel exhibited the highest activity.... 

    Efficient fatty acid esterification using silica supported Brønsted acidic ionic liquid catalyst: Experimental study and DFT modeling

    , Article Chemical Engineering Journal ; Vol. 250 , 2014 , Pages 35-41 ; ISSN: 13858947 Vafaeezadeh, M ; Hashemi, M. M ; Sharif University of Technology
    Abstract
    A task-specific Brønsted acidic ionic liquid (BAIL), 1-benzyl-3-methylimidazolium hydrogensulfate ([BnMIm]HSO4), was prepared and confined onto the high surface area silica gel. The catalyst has shown extraordinary activity in comparison of homogeneous ionic liquid (IL) system for Fischer esterification of fatty acid with ethanol. The ester derivatives were synthesized in high yields and catalyst was easily separated from the reaction mixture by simple filtration. The structure of the catalyst is theoretically modelized to investigate the unusual catalytic activity. Hence, a hydroxylated cage-like nano-cluster, H6Si8O12(OH)2, was selected to mimic the surface of silica gel. The interactions... 

    Vanadium pentoxide catalyst over carbon-based nanomaterials for the oxidative dehydrogenation of propane

    , Article Industrial and Engineering Chemistry Research ; Volume 52, Issue 46 , 2013 , Pages 16128-16141 ; 08885885 (ISSN) Fattahi, M ; Kazemeini, M ; Khorasheh, F ; Rashidi, A. M ; Sharif University of Technology
    2013
    Abstract
    A series of V2O5 catalysts supported on multiwall carbon nanotube (MWCNT), single wall carbon nanotube (SWCNT), and graphene were synthesized by hydrothermal and reflux methods for oxidative dehydrogenation of propane (ODHP) to propylene. The catalysts were characterized by techniques including the BET surface area measurements, XRD, FTIR, H2-TPR, NH3-TPD, FESEM, and UV-vis diffuse reflectance spectroscopy. The performance of the catalysts and the supports were subsequently examined in a fixed bed reactor. The main products were propylene, ethylene and CO x. The vanadium catalyst supported on graphene with C/V molar ratio of 1:1 synthesized through the hydrothermal method had the best... 

    Synthesis of Reduced Graphene Oxide-Carbon Nanotubes (rGO-CNT) Composite and Its Use As a Novel Catalyst Support for Hydro-Purification of Crude Terephthalic Acid

    , Article Industrial and Engineering Chemistry Research ; Volume 54, Issue 31 , 2015 , Pages 7591-7603 ; 08885885 (ISSN) Tourani, S ; Rashidi, A. M ; Safekordi, A. A ; Aghabozorg, H. R ; Khorasheh, F ; Sharif University of Technology
    American Chemical Society  2015
    Abstract
    Palladium nanocatalysts supported on reduced graphene oxide (rGO), multi walled carbon nanotubes (MWCNT), and rGO/CNT composite were synthesized by a wet impregnation method using PdCl2 as a precursor. Palladium loading was 0.3 wt %, and the catalysts were reduced at 300°C. The catalysts were characterized by inductively coupled plasma, Brunauer-Emmett-Teller (BET) analysis, Fourier transform infrared spectroscopy, X-ray powder diffraction, transmission electron microscopy, temperatue-programmed reduction, temperatue-programmed desorption, and Raman spectroscopy. The performance of the catalysts was investigated for hydro-purification of crude terephthalic acid (CTA) containing... 

    Effects of nano graphene oxide as support on the product properties and performance of Ziegler-Natta catalyst in production of UHMWPE

    , Article Polymers for Advanced Technologies ; Volume 26, Issue 4 , 2015 , Pages 315-321 ; 10427147 (ISSN) Kheradmand, A ; Ramazani, S. A ; Khorasheh, F ; Baghalha, M ; Bahrami, H ; Sharif University of Technology
    John Wiley and Sons Ltd  2015
    Abstract
    The synthesis of mono- and bi-supported Ziegler-Natta catalysts using magnesium etoxide Mg(OEt)2 and graphene oxide (GO) as catalyst support for production of Ultra High Molecular Weight Polyethylene (UHMWPE) is reported in this investigation. Nano-graphene oxide was prepared by the modified Hummer's method and its structure was analyzed by XRD and FTIR indicating the presence of hydroxyl groups on graphene oxide and the formation of an exfoliated structure. The activity of TiCl4/Mg(OEt)2, TiCl4/Mg(OEt)2-GO, and TiCl4/GO catalysts in terms of grams of PE produced per mmol of Ti per hour was experimentally obtained for catalysts with different ratios of co-catalyst (triisobutylaluminium) to... 

    Fabrication of MEA based on sulfonic acid functionalized carbon supported platinum nanoparticles for oxygen reduction reaction in PEMFCs

    , Article RSC Advances ; 2015 , Pages 85775-85784 ; 20462069 (ISSN) Gharibi, H ; Yasi, F ; Kazemeini, M ; Heydari, A ; Golmohammadi, F ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    The Nafion ionomer affects the efficiency of the platinum (Pt) catalyst by blocking the active sites thereby restricting the gas permeability of the catalyst layer; but, there is a limitation in the quantity of Nafion ionomer that needs to be added without affecting the cell performance. Sulfonation of carbon-supported catalysts as mixed electronic and protonic conductors has been reported to be an efficient way to increase the triple-phase boundaries. In order to improve the utilization and activity of cathodic catalysts in the oxygen reduction reaction (ORR), Pt nanoparticles were loaded on a mixture of Vulcan XC-72R and MWCNTs, which were functionalized in a mixture of 96% sulfuric acid... 

    Preparation, physiochemical and kinetic investigations of V2O5/SiO2 catalyst for sulfuric acid production

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 29, Issue 11 , 2016 , Pages 1478-1488 ; 1728144X (ISSN) Tavassoli, A ; Kazemeini, M ; Fattahi, M ; Vafajoo, L ; Sharif University of Technology
    Materials and Energy Research Center  2016
    Abstract
    V2O5/SiO2 catalyst utilized to oxidize the SO2 to SO3 species in the presence of oxygen mainly for producing sulfuric acid. For this catalyst, the active phase was a mixture of vanadium pentoxide and basic sulfate/pyrosulfate material. This active phase at the reaction temperature behaved as a liquid filling up the pores of the silica support. On the other hand, amounts of the SO3 and V5+ species in the catalyst necessarily varied with the concentration of the feed material and temperature rendering complexity to the kinetics of the SO2 oxidation reaction. In the current research, the catalyst preparation with different amounts of such materials was undertaken. Purified Diatomaceous earth of... 

    Physicochemical properties and catalytic performances of nanostructured V2O5 over TiO2 and γ-Al2O3 for oxidative dehydrogenation of propane

    , Article Chemical and Biochemical Engineering Quarterly ; Volume 30, Issue 1 , 2016 , Pages 9-18 ; 03529568 (ISSN) Kazemeini, M ; Nikkhah, M ; Fattahi, M ; Vafajoo, L ; Sharif University of Technology
    Assoc. of Chemists and Chemical Engineers of Croatia  2016
    Abstract
    Samples of V2O5 catalysts supported on nanostructures of TiO2 and γ-Al2O3 were synthesized through the hydrothermal method and used for the oxidative dehydrogenation of propane (ODHP) to propylene. The TiO2 support was utilized in both commercial microstructure and synthesized nanostructure forms. Moreover, the γ-Al2O3 support was synthesized through chemical and precipitation methods. The vanadium catalyst was then deposited onto the hybrid of the TiO2 and γ-Al2O3 materials. All prepared catalysts were characterized through the BET, FESEM, FTIR, XRD and TPR techniques. Performances of the synthesized catalysts were subsequently examined in a fixed-bed reactor. The main products were... 

    Hydrogenation of crude terephthalic acid by supported Pd and Pd-Sn catalysts on functionalized multiwall carbon nanotubes

    , Article Chemical Engineering Research and Design ; Volume 109 , 2016 , Pages 41-52 ; 02638762 (ISSN) Tourani, S ; Safekordi, A. A ; Rashidzadeh, M ; Rashidi, A. M ; Khorasheh, F ; Sharif University of Technology
    Institution of Chemical Engineers  2016
    Abstract
    Liquid phase hydro-purification of crude terephthalic acid (CTA) was performed using supported Pd and Pd-Sn catalysts on functionalized multi-wall carbon nanotubes (FMWCNT). Pd/FMWCNT catalysts were prepared by wet impregnation with Pd loadings of 0.05 to 0.6 wt.%. Pd-Sn/FMWCNT catalysts were prepared by co-impregnation (CI) and successive impregnation (SI) using 0.3 wt.% Pd loading and Sn/Pd molar ratios of 0.1 and 0.35 for the CI method and 0.05 to 0.35 for the SI method. Pd loading of 0.3 wt.% for Pd/FMWCNT was sufficient to decrease the 4-carboxybenzaldehyde (4-CBA) content of CTA from 2100 ppm to 5.5 ppm without excessive hydrogenation of terephthalic acid (TA). The commercial catalyst... 

    Production of renewable hydrogen through aqueous-phase reforming of glycerol over Ni/Al2O3–MgO nano-catalyst

    , Article International Journal of Hydrogen Energy ; Volume 43, Issue 2 , 2018 , Pages 614-621 ; 03603199 (ISSN) Bastan, F ; Kazemeini, M ; Larimi, A ; Maleki, H ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    In this study, a series of Ni nano-catalysts supported on Al2O3 and MgO were prepared through the co-precipitation technique. Effects of the Al/Mg ratio on physicochemical characteristics of Ni/Al2O3–MgO catalysts were examined. Moreover, catalytic performance was investigated in order to determine the optimum catalyst for H2 production in aqueous phase reforming (APR) of glycerol. It was revealed that, the APR activity of synthesized catalysts strongly depended on the aforementioned ratio. In addition, it was observed that, the catalytic activity of Ni/MgO and Ni/Al2O3 samples were both lower than that of the corresponding mixed oxide supports. Furthermore, it was shown that, amongst the... 

    Preparation of Ni/MeAl2O4-MgAl2O4 (Me=Fe, Co, Ni, Cu, Zn, Mg) nanocatalysts for the syngas production via combined dry reforming and partial oxidation of methane

    , Article Renewable Energy ; Volume 149 , April , 2020 , Pages 1053-1067 Jalali, R ; Rezaei, M ; Nematollahi, B ; Baghalha, M ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    In this paper, a comprehensive study was conducted on the application of various MeAl2O4 spinels (Me = Fe, Co, Ni, Cu, Zn, Mg) as the catalyst support for the preparation of nickel-based catalysts in the combined dry reforming and partial oxidation. These supports were synthesized by a novel facile sol-gel method using propylene oxide as the gelation agent and nickel was deposited on these supports by the deposition-precipitation method. The prepared samples were characterized by N2 adsorption/desorption, XRD, TPR, TPO, CO2-TPD, SEM, and TEM techniques. In addition, the temperature-programmed methane dissociation (TPMD) was performed to evaluate the effect of nickel-support interaction on... 

    Effect of rare-earth promoters (Ce, La, Y and Zr) on the catalytic performance of NiO-MgO-SiO2 catalyst in propane dry reforming

    , Article Molecular Catalysis ; Volume 522 , 2022 ; 24688231 (ISSN) Barzegari, F ; Rezaei, M ; Kazemeini, M ; Farhadi, F ; Keshavarz, A. R ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    In this contribution, NiO-MgO-SiO2 catalysts containing 3 wt. % of CeO2, La2O3, Y2O3, and Zr2O3 were examined for propane dry reforming at 550-750 °C. The samples were synthesized by a co-precipitation route, followed by a hydrothermal treatment, and characterized by BET, XRD and TPX analyses. The results indicated that the addition of promoters enhanced the metal-support interaction and basic characteristics, while the acidic nature of the promoted catalyst was changed in a different way. The highest propane conversion of 39.6% was observed over Ce-promoter sample, while the un-promoted catalyst possessed a value of 36.8% at 700 °C. Nevertheless, La and Y-promoted catalysts possessed a... 

    Preparation of ultrahigh-molecular-weight polyethylene/carbon nanotube nanocomposites with a Ziegler-Natta catalytic system and investigation of their thermal and mechanical properties

    , Article Journal of Applied Polymer Science ; Volume 125, Issue SUPPL. 1 , 2012 , Pages E453-E461 ; 00218995 (ISSN) Amoli, B. M ; Ramazani, S. A. A ; Izadi, H ; Sharif University of Technology
    Wiley  2012
    Abstract
    In this research, ultrahigh-molecular-weight polyethylene (UHMWPE)/multiwalled carbon nanotube (MWCNT) nanocomposites with different nanotube concentrations (0.5, 1.5, 2.5, and 3.5 wt %) were prepared via in situ polymerization with a novel, bisupported Ziegler-Natta catalytic system. Magnesium ethoxide [Mg(OEt) 2] and surface-functionalized MWCNTs were used as the support of the catalyst. Titanium tetrachloride (TiCl 4) accompanied by triethylaluminum constituted the Ziegler-Natta catalytic system. Preparation of the catalyst and the polymerization were carried out in the slurry phase under an argon atmosphere. Support of the catalyst on the MWCNTs was investigated with Fourier transform... 

    Supported copper and cobalt oxides on activated carbon for simultaneous oxidation of toluene and cyclohexane in air

    , Article RSC Advances ; Volume 5, Issue 7 , Dec , 2015 , Pages 5107-5122 ; 20462069 (ISSN) Zabihi, M ; Khorasheh, F ; Shayegan, J ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    Copper and cobalt oxides supported on almond shell derived activated carbon (AC) with different loadings were synthesized by sequential and co-deposition-precipitation methods leading to Cu(shell)/Co(core)/AC, Co(shell)/Cu(core)/AC and Cu-Co(mixed)/AC catalysts that were subsequently used for catalytic oxidation of gaseous mixtures of toluene and cyclohexane in air in a tubular flow reactor. The catalysts and the support were characterized by Boehm test, Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy...