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Sample records for synthesis cu-co-cr catalysts

  1. Production of Renewable Hydrogen from Glycerol Steam Reforming over Bimetallic Ni-(Cu,Co,Cr Catalysts Supported on SBA-15 Silica

    Directory of Open Access Journals (Sweden)

    Alicia Carrero

    2017-02-01

    Full Text Available Glycerol steam reforming (GSR is a promising alternative to obtain renewable hydrogen and help the economics of the biodiesel industry. Nickel-based catalysts are typically used in reforming reactions. However, the choice of the catalyst greatly influences the process, so the development of bimetallic catalysts is a research topic of relevant interest. In this work, the effect of adding Cu, Co, and Cr to the formulation of Ni/SBA-15 catalysts for hydrogen production by GSR has been studied, looking for an enhancement of its catalytic performance. Bimetallic Ni-M/SBA-15 (M: Co, Cu, Cr samples were prepared by incipient wetness co-impregnation to reach 15 wt % of Ni and 4 wt % of the second metal. Catalysts were characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES, N2-physisorption, X-ray powder diffraction (XRD, hydrogen temperature programmed reduction (H2-TPR, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and thermogravimetric analyses (TGA, and tested in GSR at 600 °C and atmospheric pressure. The addition of Cu, Co, and Cr to the Ni/SBA-15 catalyst helped to form smaller crystallites of the Ni phase, this effect being more pronounced in the case of the Ni-Cr/SBA-15 sample. This catalyst also showed a reduction profile shifted towards higher temperatures, indicating stronger metal-support interaction. As a consequence, the Ni-Cr/SBA-15 catalyst exhibited the best performance in GSR in terms of glycerol conversion and hydrogen production. Additionally, Ni-Cr/SBA-15 achieved a drastic reduction in coke formation compared to the Ni/SBA-15 material.

  2. Multi-metallic oxides as catalysts for light alcohols and hydrocarbons from synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Miguel [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Diaz, L; Galindo, H de J; Dominguez, J. M; Salmon, Manuel [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    1999-08-01

    A series of Cu-Co-Cr oxides doped with alkaline metals (M), were prepared by the coprecipitation method with metal nitrates (Cu{sup I}I, CO{sup I}I, CR{sup I}II) and (M{sub 2})CO{sub 3} in aqueous solution. The calcined products were used as catalysts for the Fisher-Tropsch synthesis in a stainless-steel fixed bed microreactor. The material was characterized by x-ray diffraction, and the specific surface area, pore size and nitrogen adsorption-desorption properties were also determined. The alkaline metals favored the methanol synthesis and prevent the dehydration reactions whereas the hydrocarbon formation is independent to these metals. [Spanish] Una serie de oxidos Cu-Co-Cr soportados con metales alcalinos (M), fueron preparados por el metodo con nitratos metalicos (Cu{sup I}I, CO{sup I}I, CR{sup I}II) y (M{sub 2})CO{sub 3} en soluciones acuosas. Los productos calcinados fueron usados como catalizadores para la sintesis de Fisher-tropsch en la superficie fija de un microreactor de acero inoxidable. El material fue caracterizado por difraccion de rayos X y el area de superficie especifica, el tamano de poro y propiedades de absorcion-desorcion de nitrogeno fueron determinadas. Los metales alcalinos favorecieron la sintesis de metanol y previnieron las reacciones de deshidratacion, mientras que la formacion de hidrocarburos es independiente de estos metales.

  3. Study of ammonia synthesis using technetium catalysts

    International Nuclear Information System (INIS)

    Spitsyn, V.I.; Mikhajlenko, I.E.; Pokrovskaya, O.V.

    1982-01-01

    A study was made on catalytic properties of technetium in ammonia synthesis reaction. The preparation of technetium catalysts on ν-Al 2 O 3 , BaTiO 3 , BaO-ν-Al 2 O 3 substrates is described. The investigation of catalytic activity of catalysts was carried out at a pressure of 1 atm. in vertical reactor with volume rate of 15000 h - 1 in the temperature range of 350-425 deg. The amount of catalyst was 0.5-1 g, the volume- 0.5 ml, the size of granules- 2-3 mm. Rate constants of ammonia synthesis reaction were calculated. Seeming activation energies of the process have meanings wihtin the limits of 40-50 kcal/mol. It was shown that with increase in concentration of Tc on BaTiO 3 the catalytic activity rises in comparison with pure Tc. The reduction of catalytic activity with increase of metal content on Al 2 O 3 begins in the limits of 3.5-6.7% Tc/ν-Al 2 O 3 . The catalyst of 5.3% Tc/4.1% Ba/ν -Al 2 O 3 compound has the maximum activity. Technetium catalysts possess the stable catalytic activity and don't requre its reduction during several months

  4. Study of ammonia synthesis over uranium catalysts

    International Nuclear Information System (INIS)

    Spitsyn, V.I.; Erofeev, B.V.; Mikhajlenko, I.E.; Gorelkin, I.I.; Ivanov, L.S.

    1980-01-01

    The effect of induced radiactivity and chemical composition of uranium catalysts on their catalytic activity in the ammonia synthesis reaction has been studied. The catalyst samples comprise pieces of metal uranium and chip irradiated in nuclear reactor by the 4.3x10 16 n/cm 2 integral flux of slow neutrons. Studies of catalytic activity was carried out at 1 atm and 340-510 deg C when stoichiometric nitrogen-hydrogen mixture passed through the following installation. At different temperatures uranium nitrides of different composition are shown to be formed. Uranium nitrides with the composition close to UN 2 are the samples with the highest catalYtic activity. The reduction of catalytic activity of uranium catalysts with the increased temperature of their formation above 400 deg C is explained by low catalytic activity of forming UNsub(1.7) in comparison with UN 2 . Catalytic properties of irradiated and nonirradiated samples do not differ from one another

  5. Cooperative catalysis designing efficient catalysts for synthesis

    CERN Document Server

    Peters, René

    2015-01-01

    Written by experts in the field, this is a much-needed overview of the rapidly emerging field of cooperative catalysis. The authors focus on the design and development of novel high-performance catalysts for applications in organic synthesis (particularly asymmetric synthesis), covering a broad range of topics, from the latest progress in Lewis acid / Br?nsted base catalysis to e.g. metal-assisted organocatalysis, cooperative metal/enzyme catalysis, and cooperative catalysis in polymerization reactions and on solid surfaces. The chapters are classified according to the type of cooperating acti

  6. The obtaining of iron acetate from processed iron comprising catalyst of ammonia synthesis

    International Nuclear Information System (INIS)

    Mansurov, M.M.; Lugovenko, A.N.; Mirzoeva, M.M.

    1993-01-01

    Present article is devoted to obtaining of iron acetate from processed iron comprising catalyst of ammonia synthesis. The method of synthesis of iron acetate from processed iron comprising catalyst of ammonia synthesis was elaborated. The structure of complex was determined.

  7. The synthesis of nanostructured, phase pure catalysts by hydrodynamic cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Moser, W.R.; Sunstrom, J.E.; Marshik-Geurts, B.J. [Worcester Polytechnic Institute, Worcester, MA (United States)

    1995-12-01

    A new process for the synthesis of advanced catalytic materials based on performing the synthesis under hydrodynamic cavitation conditions has been discovered. This continuous process for catalyst synthesis resulted in the formation of both supported and unsupported catalysts. The advantage of the process over classical methods of synthesis is that it permits the formation of a wide variety of nanostructured catalysts in exceptionally high phase purities. The synthesis of platinum and palladium catalysts supported on alumina and other supports resulted in high dispersions of the noble metals. The synthesis of alpha, beta- and gamma-bismuth molybdates resulted in catalysts having superior phase purities as compared to several other classical methods of synthesis. The beta-bismuth molybdate was synthesized directly onto Cabosil. These studies showed that the particle size of the active component could be varied from a few manometers to much larger grains. The process enabled the synthesis of other complex metal oxides like perovskites as pure phases. The process uses a commercially available Microfluidizer.

  8. Boron-containing catalysts for dry reforming of methane to synthesis gas

    KAUST Repository

    Takanabe, Kazuhiro; Basset, Jean-Marie; Park, Jung-Hyun; Samal, Akshaya Kumar; Alsabban, Bedour

    2018-01-01

    The present invention uses a cobalt catalyst for carbon dioxide reforming of lower alkanes to synthesis gas having a cobalt catalyst on an oxide support where the supported cobalt catalyst has been modified with a boron precursor. The boron

  9. Synthesis of carbon nanotubes and nanotube forests on copper catalyst

    International Nuclear Information System (INIS)

    Kruszka, Bartosz; Terzyk, Artur P; Wiśniewski, Marek; Gauden, Piotr A; Szybowicz, Mirosław

    2014-01-01

    The growth of carbon nanotubes on bulk copper is studied. We show for the first time, that super growth chemical vapor deposition method can be successfully applied for preparation of nanotubes on copper catalyst, and the presence of hydrogen is necessary. Next, different methods of copper surface activation are studied, to improve catalyst efficiency. Among them, applied for the first time for copper catalyst in nanotubes synthesis, sulfuric acid activation is the most promising. Among tested samples the surface modified for 10 min is the most active, causing the growth of vertically aligned carbon nanotube forests. Obtained results have potential importance in application of nanotubes and copper in electronic chips and nanodevices. (paper)

  10. New efficient catalyst for ammonia synthesis: barium-promoted cobalt on carbon

    DEFF Research Database (Denmark)

    Hagen, Stefan; Barfod, Rasmus; Fehrmann, Rasmus

    2002-01-01

    Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia......Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia...

  11. Enzymes as Green Catalysts for Precision Macromolecular Synthesis.

    Science.gov (United States)

    Shoda, Shin-ichiro; Uyama, Hiroshi; Kadokawa, Jun-ichi; Kimura, Shunsaku; Kobayashi, Shiro

    2016-02-24

    The present article comprehensively reviews the macromolecular synthesis using enzymes as catalysts. Among the six main classes of enzymes, the three classes, oxidoreductases, transferases, and hydrolases, have been employed as catalysts for the in vitro macromolecular synthesis and modification reactions. Appropriate design of reaction including monomer and enzyme catalyst produces macromolecules with precisely controlled structure, similarly as in vivo enzymatic reactions. The reaction controls the product structure with respect to substrate selectivity, chemo-selectivity, regio-selectivity, stereoselectivity, and choro-selectivity. Oxidoreductases catalyze various oxidation polymerizations of aromatic compounds as well as vinyl polymerizations. Transferases are effective catalysts for producing polysaccharide having a variety of structure and polyesters. Hydrolases catalyzing the bond-cleaving of macromolecules in vivo, catalyze the reverse reaction for bond forming in vitro to give various polysaccharides and functionalized polyesters. The enzymatic polymerizations allowed the first in vitro synthesis of natural polysaccharides having complicated structures like cellulose, amylose, xylan, chitin, hyaluronan, and chondroitin. These polymerizations are "green" with several respects; nontoxicity of enzyme, high catalyst efficiency, selective reactions under mild conditions using green solvents and renewable starting materials, and producing minimal byproducts. Thus, the enzymatic polymerization is desirable for the environment and contributes to "green polymer chemistry" for maintaining sustainable society.

  12. zeolite catalysts for the selective synthesis of mono- and diethylamines

    NARCIS (Netherlands)

    Veefkind, V.A.; Lercher, J.A.

    1998-01-01

    The kinetics and mechanism of ethylamine synthesis from ammonia and ethanol over several large pore acid catalysts are described. Mordenite produced higher monoethylamine yields than the zeolites beta, Y, mazzite, and amorphous silica–alumina. The reaction proceeds via the initial formation of

  13. Alum an Efficient Catalyst for Erlenmeyer Synthesis

    African Journals Online (AJOL)

    NICO

    this paper we describe the use of alum as a catalyst in the. Erlenmeyer reaction, under solvent-free condition using ultra- sonic irradiation. The application of solvent-free reaction conditions in organic chemistry has been explored extensively within the last decade. It was shown to be an efficient technique for various organic.

  14. Fischer-Tropsch synthesis : catalysts and chemistry

    NARCIS (Netherlands)

    Loosdrecht, van de J.; Botes, F.G.; Ciobica, I.M.; Ferreira, A.C.; Gibson, P.; Moodley, D.J.; Saib, A.M.; Visagie, J.L.; Weststrate, C.J.; Niemantsverdriet, J.W.; Reedijk, J.; Poeppelmeier, K.

    2013-01-01

    The Fischer–Tropsch synthesis represents a time-tested and fully proven technology for the conversion of synthesis gas (CO + H2) into paraffins, olefins, and oxygenated hydrocarbons. Depending on the origin of the syngas, one speaks of gas-to-liquids, coal-to-liquids, biomass-to-liquids, or

  15. Study of the synthesis of ammonia over technetium catalysts

    International Nuclear Information System (INIS)

    Spetsyn, V.I.; Mikhailenko, I.E.; Pokrovskaya, O.V.

    1982-01-01

    The catalytic properties of technetium in the synthesis of ammonia have been studied in the present work. Technetium catalysts according to specific yield surpass all know catalysts for the synthesis of ammonia. The enhanced catalytic activity of technetium compared to manganese and rhenium is apparently explained by the presence of the radioactivity of 99 Tc. The processes of adsorption, orientation of the adsorbed molecules, and their binding energies can differ during radiation action. Irradiation of the carrier, occurring through #betta#-emission of 99 Tc, with doses of 4-8 x 10 3 rad/day, increased the number of defects in the crystal structure where stabilization of technetium atoms was possible. The existence of charged centers can cause an increase in the dissociative chemisorption of nitrogen, which is the limiting stage of the process. Technetium catalysts possess a stable catalytic activity and do not require its restoration for several months. Results suggest that the use of technetium as a catalyst for the synthesis of ammonia has real advantages and potential possibilities

  16. Synthesis of palm biodiesel using sodium methoxide catalyst

    International Nuclear Information System (INIS)

    Azhari; Robiah Yunus; Rasyid, S.A.; Abdullah, L.C.

    2006-01-01

    Synthesis of palm biodiesel (methyl ester) was successfully carried out from refined bleached deodorized palm oil (RBDPO) by transesterification reaction. Two kinds of alkali catalyst were selected for this reaction namely sodium hydroxide (NaOH) and sodium methoxide (NaOCH 3 ), and the effects of operating variables such as molar ratio, reaction temperature and quantity of catalyst were also investigated. The reaction was carried out under atmosphere pressure. The reaction temperature and time were varied between 55 to 70 degree C and 50 to 90 minutes respectively. The methanol to oil molar ratios were also varied at 6:1, 5:1, 4:1 and 3:1 to examine its effect on reaction yield. The reaction conversion was 99% by use of NaOCH 3 as a catalyst. However, with NaOH as catalyst, the conversion was slightly lower compared to using NaOCH 3 . The optimum conditions for NaOCH 3 as catalyst were reaction temperature, 65 degree C; reaction time, 60 minutes; molar ratio, 6:1; and catalyst amount, 1.0% w/w. The kinetics study on transesterification of RBDPO with methanol established that the reaction occurred via two stepwise and irreversible elementary reactions following second order model. A vacuum distillation process was used to reduce the pour point of palm biodiesel. The lowest pour point attainable for palm biodiesel was at 3 degree C. (Author)

  17. Boron-containing catalysts for dry reforming of methane to synthesis gas

    KAUST Repository

    Takanabe, Kazuhiro

    2018-01-04

    The present invention uses a cobalt catalyst for carbon dioxide reforming of lower alkanes to synthesis gas having a cobalt catalyst on an oxide support where the supported cobalt catalyst has been modified with a boron precursor. The boron-treated cobalt catalyst systems as described herein show significant increases in the conversion of CH4 and CO2 during the dry reforming of methane (DRM) reaction as compared to traditional catalysts. Described herein are supported catalysts and methods of using the catalysts for the dry reforming of methane to synthesis gas, with the supported catalysts in the present invention include a boron-treated cobalt catalyst disposed on an oxide support. Also described herein are processes for preparing the supported catalysts.

  18. Model studies of methanol synthesis on copper catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, J.; Nakamura, I.; Uchijima, T. [Univ. of Tsukuba, Ibaraki (Japan); Watanabe, T. [Research Inst. of Innovative Technology for Earth, Kyoto (Japan); Fujitani, T. [National Inst. for Resources and Environment, Ibaraki (Japan)

    1996-12-31

    The synthesis of methanol by the hydrogenation of CO{sub 2} over Zn-deposited and Zn-free copper surfaces has been studied using an XPS apparatus combined with a high-pressure flow reactor (18 atm). It was shown that the Zn deposited on Cu(111) and poly-Cu acted as a promoter for methanol synthesis, while the Zn on Cu(110) and Cu(100) had no such a promotional effect. The turnover frequency (TOF) for Zn/Cu(111) linearly increased with Zn coverage below {Theta}Zn--0.19, and then decreased above {Theta}Zn=0.20. The optimum TOF obtained at {Theta}Zn--0-19 was thirteen-fold larger than TOF for the Zn-free Cu(111) surface. On the other hand, no promotional effect of Zn was observed for the reverse water-gas shift reaction on all the surfaces. The results indicate the formation of special sites for methanol synthesis on Zn/Cu(111). The Zn-deposited Cu(111) can be regarded as a model of Cu/ZnO catalysts because the TOF and the activation energy for methanol formation over the Zn-deposited Cu(111) were in fairly good agreement with those for the Cu/ZnO powder catalysts. The post-reaction surface analysis by XPS showed the formation of formate species (HCOOa). The formate coverage was proportional to the activity for methanol formation below {Theta}Zn=0.20, suggesting that the hydrogenation of the formate species is the rate-determining step of methanol formation. The formate species was stabilized by Zn species on Cu(111) in the absence of ZnO species. STM results on the Zn-deposited Cu(111) suggested the formation of a Cu-Zn surface alloy. The presence of special sites for methanol synthesis was also indicated in the results of powder catalysts.

  19. Mathematical Model of Synthesis Catalyst with Local Reaction Centers

    Directory of Open Access Journals (Sweden)

    I. V. Derevich

    2017-01-01

    Full Text Available The article considers a catalyst granule with a porous ceramic passive substrate and point active centers on which an exothermic synthesis reaction occurs. A rate of the chemical reaction depends on the temperature according to the Arrhenius law. Heat is removed from the pellet surface in products of synthesis due to heat transfer. In our work we first proposed a model for calculating the steady-state temperature of a catalyst pellet with local reaction centers. Calculation of active centers temperature is based on the idea of self-consistent field (mean-field theory. At first, it is considered that powers of the reaction heat release at the centers are known. On the basis of the found analytical solution, which describes temperature distribution inside the granule, the average temperature of the reaction centers is calculated, which then is inserted in the formula for heat release. The resulting system of transcendental algebraic equations is transformed into a system of ordinary differential equations of relaxation type and solved numerically to achieve a steady-state value. As a practical application, the article considers a Fischer-Tropsch synthesis catalyst granule with active cobalt metallic micro-particles. Cobalt micro-particles are the centers of the exothermic reaction of hydrocarbons macromolecular synthesis. Synthesis occurs as a result of absorption of the components of the synthesis gas on metallic cobalt. The temperature distribution inside the granule for a single local center and reaction centers located on the same granule diameter is found. It was found that there is a critical temperature of reactor exceeding of which leads to significant local overheating of the centers - thermal explosion. The temperature distribution with the local reaction centers is qualitatively different from the granule temperature, calculated in the homogeneous approximation. It is shown that, in contrast to the homogeneous approximation, the

  20. Support Functionalization To Retard Ostwald Ripening in Copper Methanol Synthesis Catalysts

    NARCIS (Netherlands)

    van den Berg, Roy; Parmentier, Tanja E.; Elkjaer, Christian F.; Gommes, Cedric J.; Sehested, Jens; Helveg, Stig; de Jongh, Petra E.; de Jong, Krijn P.

    A main reason for catalyst deactivation in supported catalysts for methanol synthesis is copper particle growth. We have functionalized the support surface in order to suppress the formation and/or transport of mobile copper species and thereby catalyst deactivation. A Stober silica support was

  1. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Klein, M.T.

    1991-12-30

    The purpose of this work is to investigate the kinetics-assisted design, synthesis and characterization of fme-pardcle, unsupported catalysts for coal liquefaction. The goal is to develop a fundamental understanding of coal catalysis and catalysts that will, in turn, allow for the specification of a novel optimal catalyst for coal liquefaction.

  2. The role of potassium as a promoter in iron catalysts for ammonia synthesis

    NARCIS (Netherlands)

    Altenburg, K.; Bosch, H.; van Ommen, J.G.; Gellings, P.J.

    1980-01-01

    Five ammonia synthesis catalysts, mainly differing in potassium content, were prepared from a commercial doubly promoted iron catalyst. The activities of these catalysts were measured at 350–450 °C and 5–200 atm. The experimental reaction rates were fitted to the modified Temkin rate equation.

  3. Fischer-Tropsch Synthesis over Iron Manganese Catalysts: Effect of Preparation and Operating Conditions on Catalyst Performance

    Directory of Open Access Journals (Sweden)

    Ali A. Mirzaei

    2009-01-01

    molar basis which is the most active catalyst for the conversion of synthesis gas to light olefins. The effects of different promoters and supports with loading of optimum support on the catalytic performance of catalysts are also studied. It was found that the catalyst containing 50%Fe/50%Mn/5 wt.%Al2O3 is an optimum-modified catalyst. The catalytic performance of optimal catalyst has been studied in operation conditions such as a range of reaction temperatures, H2/CO molar feed ratios and a range of total pressures. Characterization of both precursors and calcined catalysts is carried out by powder X-ray diffraction (XRD, scanning electron microscopy (SEM, BET specific surface area and thermal analysis methods such as TGA and DSC.

  4. Ammonia synthesis over multi-promoted iron catalysts obtained by high-energy ball-milling

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Jiang, Jianzhong; Mørup, Steen

    1999-01-01

    The feasibility of producing ammonia synthesis catalysts from high-energy ball-milling of a simple mixture of the constituent oxides has been investigated. The effect of ball-milling the fused oxidic precursor of the industrial KM1 ammonia synthesis catalyst has also been studied. The results show...

  5. Synthesis, characterization and potential utility of doped ceramics based catalysts

    Science.gov (United States)

    Sharma, Ritika; Yadav, Deepshikha; Singh, G. P.; Vyas, G.; Bhojak, N.

    2018-05-01

    Excessive utilization of petrol, diesel and other fossil fuels, continuous increase in their prices, and the big problem of carbon dioxide mission have encouraged scientists and technologist to find either new sources of energy or to develop technologies for the sustainable utilization of fuel. Biofuels are the only energy technologies that can resolve the problem of carbon dioxide emission in the atmosphere as well as reduce the amount of fossil fuel burned. Bio ethanol and biodiesel are the most common types of biofuel which are being used at present. Biodiesel has become more interesting for all the researchers in present scenario. Various feedstock viz. edible, nonedible oils, waste cooking oil, animal fat, algae etc, are using for the production of biodiesel worldwide according to their availability. Selection of efficient heterogeneous catalysts for biodiesel preparation still needs more attention of researchers. The present investigation deals with determination of synthesis, characterization and applications of doped ceramic based materials in different medium. Two of doped ceramic based catalysts which has been potentially used for the production of biodiesel. The Engine performance of biodiesel samples, made from industrial waste oils and ceramic based catalyst, have also been investigated and found up to satisfactory levels.

  6. Synthesis and application of new polymer bound catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Fetterly, Brandon Michael [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    Nitric acid has been shown to be a weak acid in acetonitrile. It is conceivable that a nitrate salt of a weakly Lewis acidic cation could furnish a ''naked'' nitrate anion as a basic catalyst in a variety of reactions in non-aqueous solvents. Such a nitrate salt could also be bound to a polymeric support via the cation, thereby allowing for reclamation and recycling of the nitrate ion. This subject is dealt with in Chapter 2, wherein my contributions consisted of performing all the reactions with the polymer supported catalyst and carrying out the experiments necessary to shed light on the reaction mechanisms. Chapter 3 contains a description of the structure and catalytic properties of an azidoproazaphosphatrane. This compound is an air-stable versatile catalyst that has proven useful not only homogeneously, but also when bound to a solid support. The synthesis of a polymer bound proazaphosphatrane containing a trivalent phosphorus is presented in Chapter 4. Such a compound has been sought after by our group for a number of years. Not only does the synthesis I have accomplished for it allow for easier separation of proazaphosphatrane catalysts from reaction mixtures, but recycling of the base is made much simpler. Proazaphosphatranes are useful homogeneous catalysts that activate atoms in other reagents, thus enhancing their reactivity. The next chapters deal with two such reactions with aldehydes and ketones, namely silylcyanations with trialkylsilylcyanides (Chapters 5 and 6) and reductions with poly(methylhydrosiloxane), in Chapter 7. In Chapter 5, Zhigang Wang performed the initial optimization and scoping of the reaction, while repetitions of the scoping experiments for reproducibility, determination of diastereomeric ratios, and experiments aimed at elucidating aspects of the mechanism were performed by me. The proazaphosphatrane coordinates to the silicon atom in both cases, thereby allowing the aforementioned reactions to proceed under

  7. Direct dimethyl-ether (DME) synthesis by spatial patterned catalyst arrangement. A modeling and simulation study

    Energy Technology Data Exchange (ETDEWEB)

    McBride, K.; Turek, T.; Guettel, R. [Clausthal Univ. of Technology (Germany). Inst. of Chemical Process Engineering

    2011-07-01

    The effect of spatially patterned catalyst beds was investigated for direct DME synthesis from synthesis gas as an example. A layered arrangement of methanol synthesis and dehydration catalyst was chosen and studied by numerical simulation under typical operating conditions for single-step DME synthesis. It was revealed that catalyst layers significantly influence the DME productivity. With an increasing number of layers from 2 to 40, an increase in DME productivity was observed approaching the performance of a physical catalyst mixture for an infinite number of layers. The results prove that a physical mixture of methanol synthesis and dehydration catalyst achieves the highest DME productivity under operating conditions chosen in this study. This can be explained by the higher average methanol concentration for the layered catalyst arrangement and thus stronger equilibrium constraints for the methanol synthesis reaction. Essentially, the layered catalyst arrangement is comparable to a cascade model of the two-step process, which is less efficient in terms of DME yield than the single-step process. However, since a significant effect was found, the layered catalyst arrangement could be beneficial for other reaction systems. (orig.)

  8. Synthesis of MoVTeNb Oxide Catalysts with Tunable Particle Dimensions

    DEFF Research Database (Denmark)

    Kolenko, Yury V.; Zhang, Wei; d'Alnoncourt, Raoul Naumann

    2011-01-01

    Reliable procedures for the controlled synthesis of phase-pure MoVTeNb mixed oxides with M1 structure (ICSD 55097) and tunable crystal dimensions were developed to study the structure sensitivity of the selective oxidation of propane to acrylic acid. A series of powdered M1 catalysts...... catalysts were studied in the selective oxidation of propane to acrylic acid, revealing that active sites appear on the entire M1 surface and illustrating the high sensitivity of catalyst performance on the catalyst synthesis method....

  9. Palladium complexes with simple iminopyridines as catalysts for polyketone synthesis.

    Science.gov (United States)

    Rosar, V; Dedeic, D; Nobile, T; Fini, F; Balducci, G; Alessio, E; Carfagna, C; Milani, B

    2016-10-07

    Four iminopyridines (N-N') differing in the nature of the substituents on the iminic carbon and on the ortho positions of the aryl ring (H or CH3) on the iminic nitrogen were used for the synthesis of neutral and monocationic palladium(ii) complexes of general formulae [Pd(CH3)Cl(N-N')] and [Pd(CH3)(NCCH3)(N-N')][PF6]. The detailed NMR characterization in solution highlighted that: (i) for both series of complexes, the Pd-CH3 signal is progressively shifted to a lower frequency on increasing the number of methyl groups on the ligand skeleton; (ii) for the neutral derivatives, the chemical shift of the (15)N NMR signals, determined through {(1)H,(15)N}-HMBC spectra, is significantly affected by the coordination to palladium; (iii) the coordination induced shift (CIS) of the nitrogen atom trans to the CH3 ligand is smaller than the other. The structure in the solid state for the neutral derivatives with all the four ligands was solved, pointing out that: (iv) the Pd-C bond distance increases with the basicity of the nitrogen-donor ligand; (v) the Pd-N bond distance correlates well with the CIS value. The combining of the solution and solid state structural features allows stating that: (vi) the Pd-CH3 singlet is a good probe for the electron donor capability of the ligand; (vii) the CIS value might be used as a probe for the strength of the Pd-N bond. All monocationic complexes generated active catalysts for the CO/vinyl arene copolymerization, leading to prevailingly syndiotactic polyketones. The catalyst performances, both in terms of catalyst productivity and polymer molecular weight, correlate well with the precatalyst structural features.

  10. The Dependence of CNT Aerogel Synthesis on Sulfur-driven Catalyst Nucleation Processes and a Critical Catalyst Particle Mass Concentration.

    Science.gov (United States)

    Hoecker, Christian; Smail, Fiona; Pick, Martin; Weller, Lee; Boies, Adam M

    2017-11-06

    The floating catalyst chemical vapor deposition (FC-CVD) process permits macro-scale assembly of nanoscale materials, enabling continuous production of carbon nanotube (CNT) aerogels. Despite the intensive research in the field, fundamental uncertainties remain regarding how catalyst particle dynamics within the system influence the CNT aerogel formation, thus limiting effective scale-up. While aerogel formation in FC-CVD reactors requires a catalyst (typically iron, Fe) and a promotor (typically sulfur, S), their synergistic roles are not fully understood. This paper presents a paradigm shift in the understanding of the role of S in the process with new experimental studies identifying that S lowers the nucleation barrier of the catalyst nanoparticles. Furthermore, CNT aerogel formation requires a critical threshold of Fe x C y  > 160 mg/m 3 , but is surprisingly independent of the initial catalyst diameter or number concentration. The robustness of the critical catalyst mass concentration principle is proved further by producing CNTs using alternative catalyst systems; Fe nanoparticles from a plasma spark generator and cobaltocene and nickelocene precursors. This finding provides evidence that low-cost and high throughput CNT aerogel routes may be achieved by decoupled and enhanced catalyst production and control, opening up new possibilities for large-scale CNT synthesis.

  11. Platinum-Bismuth Bimetallic Catalysts: Synthesis, Characterization and Applications

    OpenAIRE

    Saucedo, Jose A, Jr; Xiao, Yang; Varma, Arvind

    2015-01-01

    Bimetallic catalysts have been explored and shown to exhibit unique characteristics which are not present in monometallic catalysts. Platinum is well known as an effective catalyst for oxidation and reduction reactions, and it can be made more effective when bismuth is introduced as a promotor. Thus, the effectiveness of the Pt-Bi catalyst was demonstrated in prior work. What is not clear, however, is the mechanism behind the catalyst function; why addition of bismuth to platinum decreases de...

  12. Influence of the phase composition on the catalytic properties of ammonia synthesis catalysts

    International Nuclear Information System (INIS)

    Peev, T.M.; Bojinova, A.I.; Krylova, A.V.

    1981-01-01

    The phase composition of CA-1-type catalysts for ammonia synthesis was investigated by means of Moessbauer spectroscopy. A correlation was found between the catalytic activity of the samples and their wuestite content. (author)

  13. Sulfated polyborate: A mild, efficient catalyst for synthesis of N-tert ...

    Indian Academy of Sciences (India)

    Rapid, efficient and inexpensive method for synthesis of N-tert-butyl/N-trityl protected amides via Ritter reaction of nitriles with tertiary alcohols in the presence of a sulfated polyborate catalyst under solvent-free conditions is described. The catalyst has the advantage of Lewis as well as Bronsted acidity and recyclability ...

  14. Cobalt supported on carbon nanofibers as catalysts for the Fischer-Tropsch synthesis

    NARCIS (Netherlands)

    Bezemer, G.L.

    2006-01-01

    The Fischer-Tropsch (FT) process converts synthesis gas (H2/CO) over a heterogeneous catalyst into hydrocarbons. Generally, cobalt catalysts supported on oxidic carriers are used for the FT process, however it appears to be difficult to obtain and maintain fully reduced cobalt particles. To overcome

  15. The synthesis of higher alcohols using modified Cu/ZnO/Al@#2@#O@#3@# catalysts

    NARCIS (Netherlands)

    Slaa, J.C.; Slaa, J.C.; van Ommen, J.G.; Ross, J.R.H.; Ross, J.R.H.

    1992-01-01

    This paper gives a review of research work in the synthesis of higher alcohols over catalysts based on Cu/ZnO/Al2O3, emphasizing three main topics: (i) the effect on selectivity of the addition of several compounds to this catalyst, (ii) the effect on selectivity of the reaction conditions used, and

  16. The role of zeolite in the Fischer–Tropsch synthesis over cobalt–zeolite catalysts

    International Nuclear Information System (INIS)

    Sineva, L V; Mordkovich, V Z; Asalieva, E Yu

    2015-01-01

    The review deals with the specifics of the Fischer–Tropsch synthesis for the one-stage syncrude production from CO and H 2 in the presence of cobalt–zeolite catalytic systems. Different types of bifunctional catalysts (hybrid, composite) combining a Fischer–Tropsch catalyst and zeolite are reviewed. Special attention focuses on the mechanisms of transformations of hydrocarbons produced in the Fischer–Tropsch process on zeolite acid sites under the synthesis conditions. The bibliography includes 142 references

  17. Kinetics of acetic acid synthesis from ethanol over a Cu/SiO2 catalyst

    DEFF Research Database (Denmark)

    Voss, Bodil; Schjødt, Niels Christian; Grunwaldt, Jan-Dierk

    2011-01-01

    The dehydrogenation of ethanol via acetaldehyde for the synthesis of acetic acid over a Cu based catalyst in a new process is reported. Specifically, we have studied a Cu on SiO2 catalyst which has shown very high selectivity to acetic acid via acetaldehyde compared to competing condensation routes....... In light of this, an observed intrinsic activity difference between whole catalyst pellets and crushed pellets may be explained by the Cu crystal size and growth rate being functions of the catalyst particle size and time....

  18. Synthesis and characterization of platinum supported on alumina doped with cerium catalyst

    International Nuclear Information System (INIS)

    Yusof Abdullah; Abd Fatah Awang Mat; Mohd Ali Sufi; Sarimah Mahat; Razali Kassim; Nurhaslinda Abdullah.

    1996-03-01

    The synthesis and characterization of gamma-alumina doped with cerium as platinum support for the automobile exhaust catalyst are described. Platinum/alumina/ceria catalyst were prepared by impregnation of hexachloroplatinic acid and sintered at 500 degree Celsius to obtain metal dispersions of 1.0 wt%. Catalyst distribution inside the powder and the effects of the addition of cerium to alumina were analyzed by the scanning electron microscopy (SEM) and x-ray fluorescence spectroscopy (XRF). The results showed that the alumina - supported catalysts contained well dispersion of the noble metal

  19. Conditions for reduction of ironmolybdenum-tungsten catalyst for ammonia synthesis

    International Nuclear Information System (INIS)

    Simulina, N.A.; Karibdzhanyan, N.A.; Lachinov, S.S.; Anfimov, V.A.; Shumlyakovskij, Ts.I.

    1977-01-01

    The reduction of Fe-Mo-W catalyst MB-5, used for synthesis of ammonia, has been studied in the reactor of extracolumn reduction. The results obtained have been compared with similar results for the catalyst CA-1. It has been shown that reduction of the catalyst MB-5 proceeds more intensive and is completed at lower temperature and for a shorter period of time. The samples of the catalyst MB-5 discharged from different layers in the reactor are more active than CA-1 reduced under identical conditions

  20. Synthesis and Activation of Catalysts for Biofuel Synthesis in an Environmental Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Duchstein, Linus Daniel Leonhard; Wu, Qiongxiao; Elkjær, Christian Fink

    The synthesis of transportation fuels from sustainable resources requires new and better production paths. Our approach is to use biogas to synthesize alcohols, such as methanol or higher alcohols for fuel and other chemical products. For the production of methanol a reduction of processing...... temperature and pressure to lower the process cost and make the product more competitive is desired. Higher alcohols are in general favorable over methanol due to their high energy density and ease of use in current internal combustion engines. However, better catalysts for this reaction are needed...

  1. Hydrothermal synthesis and characterization of zirconia based catalysts

    Science.gov (United States)

    Caillot, T.; Salama, Z.; Chanut, N.; Cadete Santos Aires, F. J.; Bennici, S.; Auroux, A.

    2013-07-01

    In this work, three equimolar mixed oxides ZrO2/CeO2, ZrO2/TiO2, ZrO2/La2O3 and a reference ZrO2 have been synthesized by hydrothermal method. The structural and surface properties of these materials have been fully characterized by X-ray diffraction, transmission electron microscopy, surface area measurement, chemical analysis, XPS, infrared spectroscopy after adsorption of pyridine and adsorption microcalorimetry of NH3 and SO2 probe molecules. All investigated mixed oxides are amphoteric and possess redox centers on their surface. Moreover, hydrothermal synthesis leads to catalysts with higher surface area and with better acid-base properties than classical coprecipitation method. Both Lewis and Brønsted acid sites are present on the surface of the mixed oxides. Compared to the other samples, the ZrO2/TiO2 material appears to be the best candidate for further application in acid-base catalysis.

  2. Quantifying the promotion of Cu catalysts by ZnO for methanol synthesis

    DEFF Research Database (Denmark)

    Kuld, Sebastian; Thorhauge, Max; Falsig, Hanne

    2016-01-01

    Promoter elements enhance the activity and selectivity of heterogeneous catalysts. Here, we show how methanol synthesis from synthesis gas over copper (Cu) nanoparticles is boosted by zinc oxide (ZnO) nanoparticles. By combining surface area titration, electron microscopy, activity measurement, d...

  3. Sustainable Utility of Magnetically Recyclable Nano-Catalysts in Water: Applications in Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Manoj B. Gawande

    2013-10-01

    Full Text Available Magnetically recyclable nano-catalysts and their use in aqueous media is a perfect combination for the development of greener sustainable methodologies in organic synthesis. It is well established that magnetically separable nano-catalysts avoid waste of catalysts or reagents and it is possible to recover >95% of catalysts, which is again recyclable for subsequent use. Water is the ideal medium to perform the chemical reactions with magnetically recyclable nano-catalysts, as this combination adds tremendous value to the overall benign reaction process development. In this review, we highlight recent developments inthe use of water and magnetically recyclable nano-catalysts (W-MRNs for a variety of organic reactions namely hydrogenation, condensation, oxidation, and Suzuki–Miyaura cross-coupling reactions, among others.

  4. Synthesis and characterization of MCM-41-supported nano zirconia catalysts

    Directory of Open Access Journals (Sweden)

    Mohamed S. Abdel Salam

    2015-03-01

    Full Text Available Series of MCM-41 supported sulfated Zirconia (SZ catalysts with different loadings (2.5–7.5% wt. were prepared using direct impregnation method. The acquired solid catalysts were characterized structurally and chemically using X-RD, HRTEM, BET, FT-IR, Raman spectroscopy and TPD analysis. The acidity of the solid catalysts was investigated through cumene cracking and isopropanol dehydration at different temperatures. As the SZ loading increases, the surface acidity of the mesoporous catalysts was enhanced, this was reflected by the higher catalytic activity toward cumene cracking and isopropanol dehydration.

  5. Synthesis and comparison of the activities of a catalyst supported on two silicate materials

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Eduardo G., E-mail: eduardogv5007@gmail.com [Departamento de Física e Química, Unesp-Univ Estadual Paulista, Av. Brasil, 56-Centro, Caixa Postal 31, CEP 15385-000, Ilha Solteira, São Paulo (Brazil); Silva, Rafael O.; Carmo, Devaney R. do [Departamento de Física e Química, Unesp-Univ Estadual Paulista, Av. Brasil, 56-Centro, Caixa Postal 31, CEP 15385-000, Ilha Solteira, São Paulo (Brazil); Junior, Enes F. [Departamento de Fitotecnia, Tecnologia de Alimentos e Sócio Economia, Faculdade de Engenharia de Ilha Solteira, Universidade Estadual Paulista, Ilha Solteira, São Paulo (Brazil); Dias Filho, Newton L., E-mail: nldias@unesc.net [Departamento de Física e Química, Unesp-Univ Estadual Paulista, Av. Brasil, 56-Centro, Caixa Postal 31, CEP 15385-000, Ilha Solteira, São Paulo (Brazil); Universidade do Extremo Sul Catarinense, Av. Universitaria, 1105, CP 3167, CEP 88806-000, Criciúma, SC (Brazil)

    2017-04-15

    The focus of this work is inspecting the synthesis and comparison of the activities of a catalyst supported on two silicate materials in the epoxidation of 1-octene. The two new catalyst materials were characterized by infrared spectroscopy, elemental analysis, solid-state {sup 29}Si and {sup 13}C nuclear magnetic resonance, scanning electronic microscope (SEM) and analysis of nitrogen. Lastly, the two new catalysts, Silsesq-TCA-[(W(CO){sub 3}I{sub 2}){sub 3}] and Silica-TCA-[W(CO){sub 3}I{sub 2}] were tested as catalysts in reactions of epoxidation of 1-octene and compared with their analogue not supported [W(CO){sub 3}I{sub 2}(thiocarbamide)]. After an extensive literature search, we verified that our work is the first that has reported the immobilization process of [W(CO){sub 3}I{sub 2}(NCCH{sub 3}){sub 2}] on silsesquioxane and silica gel functionalized with propyl-thiocarbamide groups and their applications as catalysts of reactions of catalytic epoxidation of 1-octene. - Highlights: • Immobilization of [W(CO){sub 3}I{sub 2}(NCCH{sub 3}){sub 2}] complex onto mesoporous supports. • Synthesis and characterization of new mesoporous catalysts. • The new catalysts exhibit great catalytic activity in the epoxidation of 1-octene. • Recyclable catalysts with excellent reusability and stability.

  6. The synthesis of higher alcohols from CO2 hydrogenation with Co, Cu, Fe-based catalysts

    International Nuclear Information System (INIS)

    Ji, Qinqin

    2017-01-01

    CO 2 is a clean carbon source for the chemical reactions, many researchers have studied the utilization of CO 2 . Higher alcohols are clean fuel additives. The synthesis of higher alcohols from CO hydrogenation has also been studied by many researchers, but there are few literatures about the synthesis of higher alcohols from CO 2 hydrogenation, which is a complex and difficult reaction. The catalysts that used for higher alcohols synthesis need at least two active phases and good cooperation. In our study, we tested the Co. Cu. Fe spinel-based catalysts and the effect of supports (CNTs and TUD-1) and promoters (K, Na, Cs) to the HAS reaction. We found that catalyst CuFe-precursor-800 is beneficial for the synthesis of C2+ hydrocarbons and higher alcohols. In the CO 2 hydrogenation, Co acts as a methanation catalyst rather than acting as a FT catalyst, because of the different reaction mechanism between CO hydrogenation and CO 2 hydrogenation. In order to inhibit the formation of huge amount of hydrocarbons, it is better to choose catalysts without Co in the CO 2 hydrogenation reaction. Compared the functions of CNTs and TUD-1, we found that CNTs is a perfect support for the synthesis of long-chain products (higher alcohols and C2+ hydrocarbons). The TUD-1 support are more suitable for synthesis of single-carbon products (methane and methanol).The addition of alkalis as promoters does not only lead to increase the conversion of CO 2 and H 2 , but also sharply increased the selectivity to the desired products, higher alcohols. The catalyst 0.5K30CuFeCNTs owns the highest productivities (370.7 g.kg -1 .h -1 ) of higher alcohols at 350 C and 50 bar. (author) [fr

  7. Scalable synthesis of palladium nanoparticle catalysts by atomic layer deposition

    International Nuclear Information System (INIS)

    Liang Xinhua; Lyon, Lauren B.; Jiang Yingbing; Weimer, Alan W.

    2012-01-01

    Atomic layer deposition (ALD) was used to produce Pd/Al 2 O 3 catalysts using sequential exposures of Pd(II) hexafluoroacetylacetonate and formalin at 200 °C in a fluidized bed reactor. The ALD-prepared Pd/alumina catalysts were characterized by various methods including hydrogen chemisorption, XPS, and TEM, and compared with a commercially available 1 wt% Pd/alumina catalyst, which was also characterized. The content of Pd on alumina support and the size of Pd nanoparticles can be controlled by the number of ALD-coating cycles and the dose time of the Pd precursor. One layer of organic component from the Pd precursor remained on the Pd particle surface. The ALD 0.9 wt% Pd/alumina had greater active metal surface area and percent metal dispersion than the commercial 1 wt% Pd/alumina catalyst. The ALD and commercial catalysts were subjected to catalytic testing to determine their relative activities for glucose oxidation to gluconic acid in aqueous solution. The ALD 0.9 wt% Pd/alumina catalyst had comparable activity as compared to the commercial 1 wt% Pd catalyst. No noticeable amount of Pd leaching was observed for the ALD-prepared catalysts during the vigorously stirred reaction.

  8. Application of aromatization catalyst in synthesis of carbon nanotubes

    Indian Academy of Sciences (India)

    In a typical chemical vapour deposition (CVD) process for synthesizing carbon nanotubes (CNTs), it was found that the aromatization catalysts could promote effectively the formation of CNT. The essence of this phenomenon was attributed to the fact that the aromatization catalyst can accelerate the ...

  9. Synthesis of heterogeneous catalyst for the production of biodiesel ...

    African Journals Online (AJOL)

    This study explore the comparison of a suitable heterogeneous catalyst for conversion of triglyceride into fatty acid methyl ester. A series of heterogeneous cerium, manganese, and zinc oxide catalyst supported at mixture of cinder was prepared by co-precipitation and applied for conversion of triglyceride in oil to biodiesel ...

  10. Solid, double-metal cyanide catalysts for synthesis of ...

    Indian Academy of Sciences (India)

    Sci. Vol. 126, No. 2, March 2014, pp. 499–509. c Indian Academy of Sciences. Solid, double-metal cyanide catalysts for ... drimers, HPs have a highly branched structural design ... geneous catalysts and corrosion of the reactor lin- ... Carbon dioxide is a greenhouse gas. .... polymer product was reprecipitated from the liquid.

  11. Breaking the Fischer–Tropsch synthesis selectivity : Direct conversion of syngas to gasoline over hierarchical Co/H-ZSM-5 catalysts

    NARCIS (Netherlands)

    Sartipi, S.; Parashar, K.; Makkee, M.; Gascon, J.; Kapteijn, F.

    2012-01-01

    We report the combination of Fischer–Tropsch catalyst with acid functionality in one single catalyst particle. The resulting bifunctional catalyst is capable of producing gasoline range hydrocarbons from synthesis gas in one catalytic step with outstanding activities and selectivities.

  12. Magnetic nanoparticle supported phosphotungstic acid: An efficient catalyst for the synthesis of xanthene derivatives

    Science.gov (United States)

    Patel, Nipun; Katheriya, Deepak; Dadhania, Harsh; Dadhania, Abhishek

    2018-05-01

    Magnetic nanoparticle supported phosphotungstic acid (Fe3O4@SiO2-HPW) was applied as a highly efficient catalyst for the synthesis of 14H-dibenzoxanthene derivatives via condensation reaction of 2-naphthol and aryl aldehydes. The catalyst was found highly efficient for the synthesis of xanthene derivatives under solvent free condition. The catalyst showed high activity and stability during the reaction and provided excellent yield of the corresponding products in short reaction time. All the synthesized compounds were characterized through FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. Furthermore, the catalyst is magnetically recoverable and can be reused several times without significant loss of its catalytic activity.

  13. Novel Catalyst for the Chirality Selective Synthesis of Single Walled Carbon Nanotubes

    Science.gov (United States)

    2015-05-12

    Final 3. DATES COVERED (From - To) 03-April-2013 to 02-April-2015 4. TITLE AND SUBTITLE Novel Catalyst for the Chirality Selective...Distribution is unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT Chiral single walled carbon nanotubes (SWCNTs) are known to possess unique... chirality control in SWCNT synthesis. A model catalyst based on CoSO4/SiO2 was developed that showed good selectivity to (9,8) nanotubes. Remote plasma

  14. Chemical changes in non-reduced catalysts used for ammonia synthesis

    International Nuclear Information System (INIS)

    Peev, T.M.; Kyrova, Z.; Bojinova, A.I.

    1980-01-01

    Samples of non-reduced industrial catalysts CA-1 for ammonia synthesis were studied by using Moessbauer spectroscopy. The conditions of the normal storing of this catalyst were changed. After 6 months it was found that under the influence of moisture and air oxygen a considerable part of the magnetite was converted to α-Fe 2 O 3 , α-FeOOH and γ-FeOOH. (author)

  15. The synthesis of higher alcohols using modified Cu/ZnO/Al@#2@#O@#3@# catalysts

    OpenAIRE

    Slaa, J.C.; Slaa, J.C.; van Ommen, J.G.; Ross, J.R.H.; Ross, J.R.H.

    1992-01-01

    This paper gives a review of research work in the synthesis of higher alcohols over catalysts based on Cu/ZnO/Al2O3, emphasizing three main topics: (i) the effect on selectivity of the addition of several compounds to this catalyst, (ii) the effect on selectivity of the reaction conditions used, and (iii) the reaction network leading to the different products found. Although the use of alkali compounds has been studied most extensively, other compounds, for example those containing manganese,...

  16. Synthesis of methyl esters from waste cooking oil using construction waste material as solid base catalyst.

    Science.gov (United States)

    Balakrishnan, K; Olutoye, M A; Hameed, B H

    2013-01-01

    The current research investigates synthesis of methyl esters by transesterification of waste cooking oil in a heterogeneous system, using barium meliorated construction site waste marble as solid base catalyst. The pretreated catalyst was calcined at 830 °C for 4h prior to its activity test to obtained solid oxide characterized by scanning electron microscopy/energy dispersive spectroscopy, BET surface area and pore size measurement. It was found that the as prepared catalyst has large pores which contributed to its high activity in transesterification reaction. The methyl ester yield of 88% was obtained when the methanol/oil molar ratio was 9:1, reaction temperature at 65 °C, reaction time 3h and catalyst/oil mass ratio of 3.0 wt.%. The catalyst can be reused over three cycles, offer low operating conditions, reduce energy consumption and waste generation in the production of biodiesel. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Hydrogenation of levulinic acid to γ-valerolactone over anatase-supported Ru catalysts : Effect of catalyst synthesis protocols on activity

    NARCIS (Netherlands)

    Piskun, A.s.; Ftouni, J.; Tang, Z.; Weckhuysen, B.m.; Bruijnincx, P.c.a.; Heeres, Hero J.

    2018-01-01

    γ-Valerolactone (GVL) is a value-added renewable chemical with great potential and can be obtained from biomass by the hydrogenation of levulinic acid (LA) using metal-based catalysts, such as Ru/TiO2. We here report an in depth study of the effect of catalyst synthesis parameters on the performance

  18. Wet chemical synthesis of nickel supported on alumina catalysts

    International Nuclear Information System (INIS)

    Freire, Ranny Rodrigues; Costa, Talita Kenya Oliveira; Morais, Ana Carla da Fonseca Ferreira; Costa, Ana Cristina Figueiredo de Melo; Freitas, Normanda Lino de

    2016-01-01

    Heterogenic catalysts are those found to be in a different phase on the reaction when compared to the reactants and products. Preferred when compared to homogeneous catalysts due to the easiness on which the separation is processed. The objective of this study is to obtain and characterize Alumina based catalysts impregnated with Nickel (Al_2O_3), by wet impregnation. The alumina was synthesized by combustion reaction. Before and after the impregnation the catalysts were characterized by X-ray diffraction (XRD), granulometric analysis, the textural analysis will be held by nitrogen adsorption (BET), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results show a presence of a stable crystalline phase of Al2O3 in all the studied samples and after the impregnation the second phase formed was of NiO and NiAl_2O_4. The Al_2O_3 e Ni/Al_2O_3 catalysts resulted in clusters with a medium diameter of 18.9 and 14.2 μm, respectively. The catalysts show a medium-pore characteristic (medium pore diameter between 2 and 50 nm), the superficial area to Al_2O_3 and Ni/Al_2O_3 catalysts were 8.69 m"2/g and 5.56 m"2/g, respectively. (author)

  19. Synthesis and characterization of catalysts for the selective transformation of biomass-derived materials

    Science.gov (United States)

    Ghampson, Isaac Tyrone

    The experimental work in this thesis focuses on generating catalysts for two intermediate processes related to the thermal conversion of lignocellulosic biomass: the synthesis and characterization of mesoporous silica supported cobalt catalysts for the Fischer-Tropsch reaction, and an exploration of the reactivity of bulk and supported molybdenum-based nitride catalysts for the hydrodeoxygenation (HDO) of guaiacol, a lignin model compound. The first section of the work details the synthesis of a series of silica-supported cobalt Fischer-Tropsch catalysts with pore diameters ranging from 2-23 nm. Detailed X-ray diffraction measurements were used to determine the composition and particle diameters of the metal fraction, analyzed as a three-phase system containing Cofcc, Cohcp and CoO particles. Catalyst properties were determined at three stages in catalyst history: (1) after the initial calcination step to thermally decompose the catalyst precursor into Co3O4, (2) after the hydrogen reduction step to activate the catalyst to Co and (3) after the FT reaction. From the study, it was observed that larger pore diameters supported higher turnover frequency; smaller pore diameters yielded larger mole fraction of CoO; XRD on post-reduction and post-FTS catalyst samples indicated significant changes in dispersivity after reduction. In the next section, the catalytic behaviors of unsupported, activated carbon-, alumina-, and SBA-15 mesoporous silica-supported molybdenum nitride catalysts were evaluated for the hydrodeoxygenation of guaiacol (2-methoxy phenol) at 300°C and 5 MPa. The nitride catalysts were prepared by thermal decomposition of bulk and supported ammonium heptamolybdate to form MoO 3 followed by nitridation in either flowing ammonia or a nitrogen/hydrogen mixture. The catalytic properties were strongly affected by the nitriding and purging treatment as well as the physical and chemical properties of support. The overall reaction was influenced by the

  20. Promotion of Nb2O5 on the wustite-based iron catalyst for ammonia synthesis

    International Nuclear Information System (INIS)

    Han, Wenfeng; Huang, Shiliang; Cheng, Tianhong; Tang, Haodong; Li, Ying; Liu, Huazhang

    2015-01-01

    Highlights: • Niobium enhances the reduction of wustite-based ammonia synthesis catalyst significantly. • Nb 2 O 5 inhibits the segregation or formation of solid solutions on the catalyst surface. • Nb 2 O 5 doping enhances the growth rates of [2 1 1] and [2 0 0] planes rather than their amounts. - Abstract: Niobium was selected and investigated as a potential promoter for wustite-based catalyst (WBC) for ammonia synthesis. Experiments on reduction performance, activity test and H 2 -TGA, in situ XRD as well as XPS were carried out to obtain the promotion effect and mechanism involved. Niobium as a promoter was confirmed to enhance the reduction of WBC significantly. This behavior is highly desired for industry in terms of catalyst regeneration and lesser pretreatment time for fabrication regardless the unimproved catalytic performance for Nb 2 O 5 -doped wustite-based catalyst (Nb-WBC). Possible reasons for these phenomena are discussed. It is suggested that Nb 2 O 5 is not favorable for the segregation or formation of solid solutions on the catalyst surface, which are difficult to be reduced. However, it seems that niobium does not promote the growth of [2 1 1] plane, which is active for ammonia synthesis.

  1. Obtaining low temperature catalysts for methanol synthesis by no-waste process

    Energy Technology Data Exchange (ETDEWEB)

    Il' ko, E G; Sushchaya, L E; Bondar' , P G

    1982-11-01

    Low temperature production of catalysts for methanol synthesis involves considerable pollution of the environment as well as formation of side products. The authors propose producing such catalysts from joint precipitates of copper and zinc carbonates includiing stabilizers produced by decomposing solvents, then drying, aging and shaping. This method avoids waste water usually formed in scrubbing to remove ions of alkaline metals. Aluminum hydroxide is suggested as a stabilizer. The catalyst tablets prepared in this way were found to have activity like those produced by other methods, and were suitable for industrial use.

  2. Synthesis and properties of catalysts prepared from silicomolybdovanadium heteropoly acid

    International Nuclear Information System (INIS)

    Chumachenko, N.N.; Tarasova, D.V.; Nikoro, T.A.; Yaroslavtseva, I.V.

    1984-01-01

    Catalytic properties of samples prepared of silicomolybdovanadium heteropoly acid (HPA) have been investigated. The massive catalyst is shown to be comparatively low effective in the reaction of acrolein oxidation to acrylic acid. Impregnation of coarse-dispersed silica gel by the HPA solution results in the formation of active and selective catalyst, whereas low-active catalyst of deep oxidation is formed on the base of high-dispersed silica gel. The obtained data are explained by the formation and stabilization of different forms of vanadium- and molybdenum-containing compounds on the carrier surface

  3. Synthesis and Characterization of Carbon nanofibers on Co and Cu Catalysts by Chemical Vapor Deposition

    International Nuclear Information System (INIS)

    Park, Eunsil; Kim, Jongwon; Lee, Changseop

    2014-01-01

    This study reports on the synthesis of carbon nanofibers via chemical vapor deposition using Co and Cu as catalysts. In order to investigate the suitability of their catalytic activity for the growth of nanofibers, we prepared catalysts for the synthesis of carbon nanofibers with Cobalt nitrate and Copper nitrate, and found the optimum concentration of each respective catalyst. Then we made them react with Aluminum nitrate and Ammonium Molybdate to form precipitates. The precipitates were dried at a temperature of 110 .deg. C in order to be prepared into catalyst powder. The catalyst was sparsely and thinly spread on a quartz tube boat to grow carbon nanofibers via thermal chemical vapor deposition. The characteristics of the synthesized carbon nanofibers were analyzed through SEM, EDS, XRD, Raman, XPS, and TG/DTA, and the specific surface area was measured via BET. Consequently, the characteristics of the synthesized carbon nanofibers were greatly influenced by the concentration ratio of metal catalysts. In particular, uniform carbon nanofibers of 27 nm in diameter grew when the concentration ratio of Co and Cu was 6:4 at 700 .deg. C of calcination temperature; carbon nanofibers synthesized under such conditions showed the best crystallizability, compared to carbon nanofibers synthesized with metal catalysts under different concentration ratios, and revealed 1.26 high amorphicity as well as 292 m 2 g -1 high specific surface area

  4. Fischer-Tropsch synthesis in slurry-phase reactors using Co/SBA-15 catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, J.J.; Lima, L.A.; Lima, W.S.; Rodrigues, M.G.F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia Quimica], e-mail: meiry@deq.ufcg.edu.br; Fernandes, F.A.N. [Universidade Federal do Ceara (UFCE), CE (Brazil). Dept. de Engenharia Quimica

    2011-07-15

    The objective of this work is to describe the production of bifunctional catalysts using the incipient humidity method, producing catalysts with 15 wt.% cobalt supported in SBA-15 molecular sieve, to be applied in the Fischer-Tropsch (FT) reaction. The originality of this work is its focus on the use of a 15 wt.% Co/SBA-15 catalyst in FT synthesis in slurry reactors. The deposition of cobalt over SBA-15 support was accomplished by impregnation with a 0.1-M aqueous solution of cobalt nitrate. The Fischer-Tropsch synthesis was carried out with the catalyst at 240 deg C and 20 atm, under a COH{sub 2} atmosphere (molar ratio= 1), in a slurry reactor for 8 hours. X-ray diffraction measurements showed that the calcined cobalt catalyst did not modify the structure of SBA-15, proving that Co was present under the form of Co{sub 3}O{sub 4} in the catalyst. The addition of cobalt in the SBA-15 decreased the specific superficial area of the molecular sieve. The 15 wt.% Co/SBA-15 catalyst had a 40% CO conversion rate and a high selectivity towards the production of C{sub 5}{sup +} (53.9% after 8 hours). (author)

  5. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review

    Directory of Open Access Journals (Sweden)

    Hartati Hartati

    2013-06-01

    Full Text Available This paper reviews various types of heterogeneous acid-base catalysts for fragrances preparation. Catalytic activities of various types of heterogeneous acid and base catalysts in fragrances preparation, i.e. non-zeolitic, zeolitic, and mesoporous molecular sieves have been reported. Generally, heterogeneous acid catalysts are commonly used in fragrance synthesis as compared to heterogeneous base catalysts. Heteropoly acids and hydrotalcites type catalysts are widely used as heterogeneous acid and base catalysts, respectively. © 2013 BCREC UNDIP. All rights reservedReceived: 20th January 2013; Revised: 31st March 2013; Accepted: 1st April 2013[How to Cite: Hartati, H., Santoso, M., Triwahyono, S., Prasetyoko, D. (2013. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 14-33. (doi:10.9767/bcrec.8.1.4394.14-33][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4394.14-33] | View in  |

  6. synthesis and charact catalyst for the production o thesis

    African Journals Online (AJOL)

    userpc

    THESIS AND CHARACTERIZATION OF SOLID HETEROGENEOUS. R THE PRODUCTION OF ... r ratio, 2wt% catalyst loading, 80oC reaction temperature and talyst maintained ... The analysis was carried out on a Shimadzu model XRD6000 ...

  7. Bisphenol A Synthesis - Modeling of Industrial Reactor and Catalyst Deactivation

    Czech Academy of Sciences Publication Activity Database

    Prokop, Zdeněk; Hanková, Libuše; Jeřábek, Karel

    2004-01-01

    Roč. 60, - (2004), s. 77-83 Sp/Iss/ SI ISSN 1381-5148. [Asia-Pacific Congress on Catalysis /3./. Dalian, 12.10.2003-15.10.2003] R&D Projects: GA ČR GA104/02/1104 Institutional research plan: CEZ:AV0Z4072921 Keywords : bisphenol A * catalyst deactivation * ion exchanger catalyst Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.582, year: 2004

  8. Reactions of synthesis gas on silica supported transition metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Niemelae, M. [VTT Chemical Technology, Espoo (Finland). Lab. of Industrial Chemistry

    1997-12-31

    The effect of catalyst precursor and composition on the activation of CO was investigated using CO hydrogenation as a test reaction. The interrelations of preparation, pretreatment, characteristics and activity were clarified. For Co/SiO{sub 2} catalyst, MgO promotion increased the CO adsorption capacity and the hydrogen uptake, although the extent of reduction for cobalt remained the same or decreased. The conversion per active metallic cobalt site consequently increased in conjunction with MgO promotion, while the effect on overall performance per 1 g of catalyst remained moderate. The precursor affected the performance of Co/SiO{sub 2} considerably. CO was more strongly adsorbed on catalysts of carbonyl origin than on those derived from cobalt nitrate, the activity thus being higher. Although the nitrate derived Co/SiO{sub 2} appeared both to retain its activity and to regain its adsorption capacity better than the catalysts of carbonyl origin, the performance of the latter was superior with time on stream. For tetranuclear cluster based Co-Ru and Co-Rh catalysts, rhodium or ruthenium was in contact with the support and cobalt was enriched on top. On Co-Ru/SiO{sub 2} ruthenium enhanced deactivation, and no benefits in activity or oxygenate selectivity were achieved relative to the monometallic catalysts of cluster origin. The Co-Rh/SiO{sub 2} catalysts were also less active than those derived from monometallic clusters, but they exhibited higher selectivities to oxygenated compounds due to the presence of active sites on the perimeter of the cobalt particles located on rhodium. The highest selectivity to oxygenates was achieved by changing the decomposition atmosphere of Rh{sub 4}(CO){sub 12}/SiO{sub 2} from hydrogen to carbon monoxide. The results also showed two types of active sites to be operative in the formation of oxygenates - one for ethanol and another for aldehydes. (orig.) 69 refs.

  9. Polystyrene-supported pyridinium chloroaluminate ionic liquid as a new heterogeneous Lewis acid catalyst for selective synthesis of benzimidazoles

    Directory of Open Access Journals (Sweden)

    Parvanak Boroujeni Kaveh

    2013-01-01

    Full Text Available Polystyrene-supported pyridinium chloroaluminate ionic liquid was prepared from the reaction of Merrifield resin with pyridine followed by reaction with aluminium chloride. This catalyst was used as a new chemoselective Lewis acid catalyst for the exclusive synthesis of 2-substituted benzimidazoles from the reaction of aldehydes with o-phenylenediamines. The catalyst is stable (as a bench top catalyst and can be easily recovered and reused without appreciable change in its efficiency.

  10. The role of zeolites in the deactivation of multifunctional fischer-tropsch synthesis catalysts: the interaction between HZSM-5 and Fe-based Ft-catalysts

    Directory of Open Access Journals (Sweden)

    P. C. Zonetti

    2013-12-01

    Full Text Available In order to produce gasoline directly from syngas, HZSM-5 can be added to the Fischer-Tropsch catalyst. However, this catalytic system shows an important deactivation rate. Aiming at describing this phenomenon, Fe-based catalysts and physical mixtures containing these catalysts and HZSM-5 were employed in this reaction. All these systems were characterized using the following techniques: XRD, XPS, TPR and TPD of CO. This work shows that HZSM-5 interacts with the Fe-based Fischer-Tropsch catalyst during the reduction step, decreasing the Fe concentration on the catalytic surface and thus lowering the activity of the catalytic system in the Fischer-Tropsch Synthesis.

  11. The role of zeolites in the deactivation of multifunctional Fischer-Tropsch Synthesis catalysts: the interaction between HZSM-5 and Fe-based FT-catalysts

    International Nuclear Information System (INIS)

    Zonetti, P.C.; Gaspar, A.B.; Mendes, F.M.T.; Appel, L.G.; Avillez, R. R. de; Sousa-Aguiar, E.F.

    2013-01-01

    In order to produce gasoline directly from syngas, HZSM-5 can be added to the Fischer-Tropsch catalyst. However, this catalytic system shows an important deactivation rate. Aiming at describing this phenomenon, Fe-based catalysts and physical mixtures containing these catalysts and HZSM-5 were employed in this reaction. All these systems were characterized using the following techniques: XRD, XPS, TPR and TPD of CO. This work shows that HZSM-5 interacts with the Fe-based Fischer-Tropsch catalyst during the reduction step, decreasing the Fe concentration on the catalytic surface and thus lowering the activity of the catalytic system in the Fischer-Tropsch Synthesis. (author)

  12. The role of zeolites in the deactivation of multifunctional Fischer-Tropsch Synthesis catalysts: the interaction between HZSM-5 and Fe-based FT-catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zonetti, P.C.; Gaspar, A.B.; Mendes, F.M.T.; Appel, L.G., E-mail: lucia.appel@int.gov.br [Instituto Nacional de Tecnologia (INT/MCT), Rio de Janeiro, RJ (Brazil); Avillez, R. R. de [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil); Sousa-Aguiar, E.F. [Centro de Pesquisa Leopoldo Americo Miguez de Mello (CENPES/PETROBRAS), Rio de Janeiro, RJ (Brazil)

    2013-10-15

    In order to produce gasoline directly from syngas, HZSM-5 can be added to the Fischer-Tropsch catalyst. However, this catalytic system shows an important deactivation rate. Aiming at describing this phenomenon, Fe-based catalysts and physical mixtures containing these catalysts and HZSM-5 were employed in this reaction. All these systems were characterized using the following techniques: XRD, XPS, TPR and TPD of CO. This work shows that HZSM-5 interacts with the Fe-based Fischer-Tropsch catalyst during the reduction step, decreasing the Fe concentration on the catalytic surface and thus lowering the activity of the catalytic system in the Fischer-Tropsch Synthesis. (author)

  13. Synthesis of solid catalyst from egg shell waste and clay for biodiesel production

    Science.gov (United States)

    Setiadji, S.; Sundari, C. D. D.; Munir, M.; Fitriyah, S.

    2018-05-01

    Until now, energy consumption in Indonesia is almost entirely fulfilled by fossil fuels, thus, its availability will be limited and continue to decrease. To overcome these problems, development and utilization of renewable energy are required, one of which is biodiesel. Biodiesel can be prepared through transesterification reaction of vegetable oil using catalyst. In this research, a solid catalyst for biodiesel synthesis was prepared from chicken egg shell waste and clay. Optimization of the transesterification reaction of coconut (Cocos nucifera) oil to obtain biodiesel was also carried out. The formation of CaO/kaolin catalyst was confirmed based on the results of XRD and SEM-EDS. This catalyst is suitable for biodiesel synthesis from vegetable oils with lower FFA (free fatty acid) levels, i.e. coconut oil with FFA level of 0.18%. Based on FTIR result, FFA level and flame tests, it was found that biodiesel was successfully formed. Synthesis of biodiesel has the optimum conditions on reaction time of 16 hours and temperature of 64 °C, with oil: methanol ratio of 1: 15 and CaO/kaolin catalyst concentration of 0.9% in a reflux system.

  14. The effect of alkaline doped catalysts on the CVD synthesis of carbon nanotubes

    DEFF Research Database (Denmark)

    Nemeth, Krisztian; Nemeth, Zoltan; Fejes, Dora

    2011-01-01

    The aim of this work was to develop new doped catalysts for chemical vapour deposition (CVD) synthesis in order to increase the quantity and quality of carbon nanotubes (CNTs). Doping compounds such as CsBr, CsCl, KBr and KCl were used to reach higher carbon deposit and carbon yield. The amount o...... of the dopant alkali compounds varied from 1 to 5%. As prepared CNTs were characterized by transmission electron microscopy (TEM), X‐ray diffraction (XRD) and Raman microscopy. Results revealed that both carbon yield and deposit could be increased over doped catalysts.......The aim of this work was to develop new doped catalysts for chemical vapour deposition (CVD) synthesis in order to increase the quantity and quality of carbon nanotubes (CNTs). Doping compounds such as CsBr, CsCl, KBr and KCl were used to reach higher carbon deposit and carbon yield. The amount...

  15. Optimization of Rhodium-Based Catalysts for Mixed Alcohol Synthesis – 2012 Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, Mark A.; Gray, Michel J.; Albrecht, Karl O.; Thompson, Becky L.

    2012-11-01

    Pacific Northwest National Laboratory has been conducting research to investigate the feasibility of producing mixed alcohols from biomass-derived synthesis gas (syngas). In recent years, this research has primarily involved the further development of catalysts containing rhodium and manganese based on the results of earlier catalyst screening tests. Testing continued in FY 2012 to further improve the Ir-promoted RhMn catalysts on both silica and carbon supports for producing mixed oxygenates from synthesis gas. This testing re-examined selected alternative silica and carbon supports to follow up on some uncertainties in the results with previous test results. Additional tests were conducted to further optimize the total and relative concentrations of Rh, Mn, and Ir, and to examine selected promoters and promoter combinations based on earlier results. To establish optimum operating conditions, the effects of the process pressure and the feed gas composition also were evaluated.

  16. ZnO nanoparticle as catalyst for efficient green one-pot synthesis of ...

    Indian Academy of Sciences (India)

    The zinc oxide (ZnO) nanoparticles functions as highly effective catalyst for the reactions of various o-hydroxy ... the synthesis of relatively large and complex molecules .... of ethylene diamine in hydrothermal ZnO nanorod syn- thesis. Di- and ...

  17. Facile, eco-friendly, catalyst-free synthesis of polyfunctionalized quinoxalines.

    Science.gov (United States)

    Zhang, Yaohong; Luo, Mengqiang; Li, Yan; Wang, Hai; Ren, Xiaorong; Qi, Chenze

    2018-02-01

    A novel, facile and eco-friendly synthesis of quinoxalines from [Formula: see text] and 1,2-diamines was developed. An attractive feature of this protocol is that the desired products could be generated efficiently in water and without any catalyst, which is in accordance with the aim of green chemistry. A plausible mechanism has been proposed.

  18. Transient behavior of Cu/ZnO-based methanol synthesis catalysts

    DEFF Research Database (Denmark)

    Vesborg, Peter Christian Kjærgaard; Chorkendorff, Ib; Knudsen, Ida

    2009-01-01

    Time-resolved measurements of the methanol synthesis reaction over a Cu/ZnO-based catalyst reveal a transient methanol production that depends on the pretreatment gas. Specifically, the methanol production initially peaks after a pretreatment with an intermediate mixture of H2 and CO (20–80% H2...

  19. Boric acid as a mild and efficient catalyst for one-pot synthesis of 1

    Indian Academy of Sciences (India)

    Abstract. An efficient green chemistry method has been developed for the synthesis of 1-amidoalkyl-2-naphthol derivatives via a one-pot three-component condensation of 2-naphthol, aldehydes and amide in the presence of boric acid as a mild catalyst.

  20. Silica Sulfuric Acid: An Eco-Friendly and Reusable Catalyst for Synthesis of Benzimidazole Derivatives

    Directory of Open Access Journals (Sweden)

    Bahareh Sadeghi

    2013-01-01

    Full Text Available Silica sulfuric acid (SiO2-OSO3H as an eco-friendly, readily available, and reusable catalyst is applied to benzimidazole derivatives synthesis under reflux in ethanol. The procedure is very simple and the products are isolated with an easy workup in good-to-excellent yields.

  1. Synthesis of Cyclododecatriene from 1,3-Butadiene by Trimerization over Amine-Titanium Complex Catalyst

    International Nuclear Information System (INIS)

    Park, Da Min; Kim, Gye Ryung; Lee, Ju Hyun; Kim, Geon-Joong; Cho, Deuk Hee

    2013-01-01

    The new complex catalysts were synthesized by the reaction of titanium compounds (titanium chloride or titanium butoxide) and diamines in this work, and they showed very high catalytic activities for the cyclododecatriene (CDT) synthesis from 1,3-butadiene through trimerization. CDT synthetic reaction was performed in an autoclave reactor, and the effects of reaction temperature, type of catalyst, catalyst amount added into the system, the mole ratio of Al/Ti and immobilization method were investigated on the yield of product CDT. The titanium complex catalyst combined to diamine with 1:1 ratio showed high selectivity to CDT more than 90%. The ratio of TTT-CDT/TTC-CDT isomers in the product revealed as different values, depending on the type of diamine combined to titanium and Ti/diamine ratios. Those homogeneous complexes could be used as a heterogenized catalyst after anchoring on the supports, and the immobilized titanium catalyst retained the catalytic activities for several times in the recycled reactions without leaching. The carbon support containing titanium has exhibited superior activity to the silica support. Especially, when the titanium complex was anchored on the support which was fabricated by the hydrolysis of tripropylaminosilane itself, the resulting titanium catalyst showed the highest BD conversion and CDT selectivity

  2. Synthesis and essay of an Ionomer like catalyst of olefins epoxidation

    International Nuclear Information System (INIS)

    Boyaca Mendivelso, Alejandro; Tempesti, Ezio

    1995-01-01

    The purpose of the present work is the preparation of an ionomer with base in Molybdenum and to evaluate its activity like catalyst of olefins epoxidation like alternative of synthesis of catalysts of the Hawk process. A polymer is synthesized with available functional groups to stabilize the metal starting from sodium molybdate; the characterization is made by atomic absorption, spectroscopy to GO, and X.P.S. The characterization indicates that indeed it is possible to stabilize the Mo in the main polymeric. The evaluation in reaction in liquid phase allows similar conversions to those of a homogeneous catalyst. The selective epoxidation of olefins for alkyl hydroperoxides, it has acquired great importance inside the industrial processes obtaining of propylene oxide due to the recent use of the terbutilic alcohol (co-produced together with the epoxide), as preservative in gasoline free of lead. In the environment of these processes, and in particular in the Hawk process possibilities of technological innovation, in the concerning to the heterogenization of conventional catalysts, at the moment used in homogeneous phase. The present work collaborate to some tentative that look for to generate alternative of preparation of catalysts for the process Hawk, synthesizing and testing the activity of an ionomer like epoxidation catalyst, which tries to reproduce the chemical structure of the complexes organ-metallic pear to suppress the separation stages and necessary recovery facilitating its recurrent reutilization with eventual economic repercussions in the industrial process. It is described the procedure of synthesis of the ionomer, the characterization and the evaluation of the activity in reaction under diverse conditions. Of the made characterization it comes off that the heterogenization of catalysts for olefins epoxidation, according to the Hawk process, is possible by means of the preparation of polymers modified appropriately. Likewise the evaluation in

  3. One-step flame synthesis of an active Pt/TiO2 catalyst for SO2 oxidation

    DEFF Research Database (Denmark)

    Johannessen, Tue; Koutsopoulos, Sotiris

    2002-01-01

    Flame synthesis as a route for production of composite metal oxides has been employed for the one-step synthesis of a supported noble metal catalyst, i.e. a Pt/TiO2 catalyst, by simultaneous combustion of Ti-isopropoxide and platinum acetylacetonate in a quench-cooled flame reactor. The average...... size of the platinum particles supported on aggregated nano-particles of TiO2 is approximately 2 nm. The high SO2-oxidation activity of the catalyst proves that platinum is not hidden in the titania matrix. The flame-produced catalyst showed catalytic activity similar to samples prepared by wet...

  4. Recent Applications of Polymer Supported Organometallic Catalysts in Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Nina Kann

    2010-09-01

    Full Text Available Recent developments concerning the application of polymer supported organometallic reagents in solid phase synthesis are reviewed, with a special focus on methodology for carbon-carbon formation. Examples of reactions that are covered include the classical Suzuki, Sonogashira and Heck coupings, but also aryl amination, epoxide opening, rearrangements, metathesis and cyclopropanation. Applications in the field of asymmetric synthesis are also discussed.

  5. Synthesis Under 'Greener' Conditions: Role of Sustainable Nano-Catalysts

    Science.gov (United States)

    The presentation summarizes our recent activity in chemical synthesis involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a varie...

  6. New Titanium-Based Catalysts for the Synthesis of Poly(ethylene terephthalate)

    International Nuclear Information System (INIS)

    Yang, Youngkeun; Yoon, Seungwoong; Hwang, Yongtaek; Song, Bogeun

    2012-01-01

    Poly(ethylene terephthalate) (PET) is a polymer with relatively low cost and high performance, which is widely used in various applications such as bottles, textile fibers, films and engineering plastics for automobiles and electric industries. Commercial catalysts used for synthesis of PET are in general antimony (Sb) compounds. Antimony(III) oxide, antimony(III) acetate and antimony(III) glycolate are used as a catalyst in 95% of PET manufacturing industries worldwide. The few organoantimony compounds that have been identified in environmental and biological samples are all in the form of methylated Sb-species. The Sb trace element is extremely toxic to mammals, and interferes with embryonic and fetal development, also, carcinogenic to humans. In addition to being found in drinking water, food packaging and soft-drink bottles. According to the World Health Organization (WHO), Sb species concentration lower than 20 ppb are acceptable for drinking water. According to a recent study, in 14 brands of bottled water from Canada, Sb concentrations increased on average 19% during 6 months storage at room temperature, but 48 brands of water from 11 European countries increased on average 90% under identical conditions. Therefore, a very important challenge for polyester catalysis is to come-up with a new Sb-free catalysts with low environmental impact. Intensive efforts have been made to find other stable and more environmental friendly non-antimony catalysts, such as those based on titanium. Titanium-based catalysts have been known for many years and actually are used for polybutylene terephthalate (PBT) and polypropylene terephthalate (PPT) production, however, polycondensation (PC) of PET manufacture is not well studied in literature. To date, only few esterification processes have been applied for the synthesis of PET by titanium catalysts. Herein, we report an efficient synthesis characterization and polymerization of PET for a series of new nontoxic organotitanium

  7. Ammonia synthesis by means of plasma over MgO catalyst

    International Nuclear Information System (INIS)

    Sugiyama, K.; Akazawa, K.; Matsuda, T.; Miura, H.; Oshima, M.

    1986-01-01

    Ammonia synthesis from H 2 -N 2 mixed gas was studied at room temperature in a glow-discharge plasma in the presence of metals or metal oxides. Magnesia (Mg0) and calcia (CaO), which are oxides with solid basicity, revealed catalytic activity in the plasma synthesis of ammonia, although they are catalytically inactive in industrial ammonia synthesis. The acid oxides (Al 2 0 3 W0 3 , and Si0 2 -Al 2 0 3 ) lead to the consumption of the reactant, i.e., the H2-N2 mixed gas. No ammonia was isolated. Metal catalysts showed higher activity than the above basic oxides. They have, however, different activities. The reaction was faster over the active materials than over sodium chloride (NaCl) or glass wool or in a blank reactor without any catalyst

  8. Mechanochemical synthesis of TiO2/NiFe2O4 magnetic catalysts for operation under RF field

    International Nuclear Information System (INIS)

    Houlding, Thomas K.; Gao, Pengzhao; Degirmenci, Volkan; Tchabanenko, Kirill; Rebrov, Evgeny V.

    2015-01-01

    Highlights: • Novel NiFe 2 O 4 –TiO 2 composite magnetic catalysts have been prepared by mechanochemical synthesis. • The synthesis time of 30 min provides the highest specific absorption rate (SAR) in RF heating. • Formation of NiTiO 3 phase during calcination decreases the SAR of the catalysts. • High stability of the NiFe 2 O 4 –TiO 2 catalyst was observed in a continuous amide bond synthesis under RF heating. - Abstract: Composite NiFe 2 O 4 –TiO 2 magnetic catalysts were prepared by mechanochemical synthesis from a mixture of titania supported nickel ferrite nanoparticles and P25 titania (Evonic). The former provides fast and efficient heating under radiofrequency field, while the latter serves as an active catalyst or catalyst support. The highest heating rate was observed over a catalyst prepared for a milling time of 30 min. The catalytic activity was measured over the sulfated composite catalysts in the condensation of aniline and 3-phenylbutyric acid in a stirred tank reactor and in a continuous RF heated flow reactor in the 140–170 °C range. The product yield of 47% was obtained over the sulfated P25 titania catalyst in the flow reactor

  9. Silver-palladium catalysts for the direct synthesis of hydrogen peroxide

    Science.gov (United States)

    Khan, Zainab; Dummer, Nicholas F.; Edwards, Jennifer K.

    2017-11-01

    A series of bimetallic silver-palladium catalysts supported on titania were prepared by wet impregnation and assessed for the direct synthesis of hydrogen peroxide, and its subsequent side reactions. The addition of silver to a palladium catalyst was found to significantly decrease hydrogen peroxide productivity and hydrogenation, but crucially increase the rate of decomposition. The decomposition product, which is predominantly hydroxyl radicals, can be used to decrease bacterial colonies. The interaction between silver and palladium was characterized using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR). The results of the TPR and XPS indicated the formation of a silver-palladium alloy. The optimal 1% Ag-4% Pd/TiO2 bimetallic catalyst was able to produce approximately 200 ppm of H2O2 in 30 min. The findings demonstrate that AgPd/TiO2 catalysts are active for the synthesis of hydrogen peroxide and its subsequent decomposition to reactive oxygen species. The catalysts are promising for use in wastewater treatment as they combine the disinfectant properties of silver, hydrogen peroxide production and subsequent decomposition. This article is part of a discussion meeting issue 'Providing sustainable catalytic solutions for a rapidly changing world'.

  10. Synthesis of 2D Nitrogen-Doped Mesoporous Carbon Catalyst for Oxygen Reduction Reaction

    Directory of Open Access Journals (Sweden)

    Zhipeng Yu

    2017-02-01

    Full Text Available 2D nitrogen-doped mesoporous carbon (NMC is synthesized by using a mesoporous silica film as hard template, which is then investigated as a non-precious metal catalyst for the oxygen reduction reaction (ORR. The effect of the synthesis conditions on the silica template and carbon is extensively investigated. In this work, we employ dual templates—viz. graphene oxide and triblock copolymer F127—to control the textural features of a 2D silica film. The silica is then used as a template to direct the synthesis of a 2D nitrogen-doped mesoporous carbon. The resultant nitrogen-doped mesoporous carbon is characterized by transmission electron microscopy (TEM, nitrogen ad/desorption isotherms, X-ray photoelectron spectroscopy (XPS, cyclic voltammetry (CV, and rotating disk electrode measurements (RDE. The electrochemical test reveals that the obtained 2D-film carbon catalyst yields a highly electrochemically active surface area and superior electrocatalytic activity for the ORR compared to the 3D-particle. The superior activity can be firstly attributed to the difference in the specific surface area of the two catalysts. More importantly, the 2D-film morphology makes more active sites accessible to the reactive species, resulting in a much higher utilization efficiency and consequently better activity. Finally, it is noted that all the carbon catalysts exhibit a higher ORR activity than a commercial Pt catalyst, and are promising for use in fuel cells.

  11. Alum as a Catalyst for the Synthesis of Bispyrazole Derivatives

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Zolfigol

    2016-01-01

    Full Text Available Compounds with pyrazolemoieties as nitrogen-containing heterocyclic systems have received attention owing to their diverse biological activities. Alum (KAl(SO42∙12H2O is an inexpensive, reusable and nontoxic catalyst used to synthesize 1H-pyrazole derivatives via the reaction of 3-methyl-1-phenyl-1H-pyrazol-5(4H-one and carbonyl compound under solvent-free conditions at 60 °C. The proposed method has been used for the preparation of 1H-pyrazole derivatives to yield green products for cleaning-in-place and to avoid toxic catalysts and hazardous solvents in accordance with the philosophy of sustainable chemistry.

  12. Study of the butyl acetate synthesis - 1. Catalyst selection

    Directory of Open Access Journals (Sweden)

    Álvaro Orjuela Londoño

    2004-01-01

    Full Text Available In this work, a laboratory scale selection study over eight catalytic agents was made, in the acetic acid and butyl alcohol esterification reaction (seven lon exchange resins and a zeolytic solid. Considering some physicochemical characteristics as the activation pre-treating requirements, acidity, thermal stability, reaction performance, etc., it was found that macroporous ion exchange resins are the most efficient catalysts, especially Lewatit K-2431 resin.

  13. Nickel nanoparticles: A highly efficient catalyst for one pot synthesis ...

    Indian Academy of Sciences (India)

    and KANIKA VIJ. Department of Chemistry, University of Delhi, Delhi 110 007, India ... Keywords. PVP-stabilized Ni nanoparticles; ethylene glycol; tetraketones; biscoumarins; ... ing interest in using nickel nanoparticles in organic synthesis ...

  14. Synthesis of Carbon Nano tubes Using Anadara Granosa Shells as Catalyst Support

    International Nuclear Information System (INIS)

    Mohd Zobir Hussein; Mohd Zobir Hussein; Salwani Asyikin Zakarya; Siti Halimah Sarijo

    2011-01-01

    The synthesis of carbon nano tubes (CNTs) by chemical vapor deposition (CVD) method using natural calcite prepared from Anadara granosa shells (CS), as metal catalyst support was studied. Hexane and iron were used as carbon precursor and catalyst, respectively. The as synthesised CNTs was characterized using XRD, TEM and FESEM. From the XRD patterns the CNTs peak can be seen more incisive after purification process and from the FESEM micrographs the CNTs can be seen as a bunch of rope-like structures. (author)

  15. Cobalt catalysts for the conversion of methanol and for Fischer-tropsch synthesis to produce hydrocarbons

    International Nuclear Information System (INIS)

    Mauldin, C.H.; Davis, S.M.; Arcuri, K.B.

    1987-01-01

    A regeneration stable catalyst is described for the conversion at reaction conditions of methanol or synthesis gas to liquid hydrocarbons which consists essentially of from about 2 percent to about 25 percent cobalt, based on the weight of the catalyst composition, composited with titania, or a titania-containing support, to which is added sufficient of a zirconium, hafnium, cerium, or uranium promoter to provide a weight ratio of the zirconium, hafnium, cerium, or uranium metal:cobalt greater than about 0.101:1

  16. Synthesis of Dimethyl Glutarate from Cyclobutanone and Dimethyl Carbonate over Solid Base Catalysts

    International Nuclear Information System (INIS)

    Zhi, Chen; Dudu, Wu

    2012-01-01

    A facile route for the synthesis of dimethyl glutarate (DMG) from cyclobutanone and dimethyl carbonate (DMC) in the presence of solid base catalysts has been developed. It was found that the intermediate carbomethoxycyclobutanone (CMCB) was produced from cyclobutanone with DMC in the first step, and then CMCB was further converted to DMG by reacting with a methoxide group. The role of the basic catalysts can be mainly ascribed to the activation of cyclobutanone via the abstraction of a proton in the α-position by base sites, and solid bases with moderate strength, such as MgO, favor the formation of DMG

  17. Synthesis of Dimethyl Glutarate from Cyclobutanone and Dimethyl Carbonate over Solid Base Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zhi, Chen; Dudu, Wu [Guangdong Medical College, Dongguan (China)

    2012-06-15

    A facile route for the synthesis of dimethyl glutarate (DMG) from cyclobutanone and dimethyl carbonate (DMC) in the presence of solid base catalysts has been developed. It was found that the intermediate carbomethoxycyclobutanone (CMCB) was produced from cyclobutanone with DMC in the first step, and then CMCB was further converted to DMG by reacting with a methoxide group. The role of the basic catalysts can be mainly ascribed to the activation of cyclobutanone via the abstraction of a proton in the {alpha}-position by base sites, and solid bases with moderate strength, such as MgO, favor the formation of DMG

  18. The effect of zirconium on cobalt catalyst in fischer-tropsch synthesis

    International Nuclear Information System (INIS)

    Moradi, GH.R.; Mahbob Basir, M.; Taeb, A.

    2003-01-01

    A series of 10 wt % Co/SiO 2 catalysts with different loading ratios of zirconia (0, 5, 10, 15, 20) has been prepared through an original pseudo sol-gel method. All catalysts were characterized by BET, XRD, SEM, and TPR experiments. The catalytic performance of the catalysts for the so-called fischer- tropsch synthesis was examined under H 2 /CO=2 at 230 d ig C and 8 bar in a fixed bed microreactor. By increasing zirconia, the Co-SiO 2 interaction decreases and is replaced by Co-Zr interaction which favours reduction of the catalyst at lower temperatures. While it leads to a higher degree of reduction and as increase in the metallic cobalt atoms on the surface. The activity of the promoted catalysts increases with the addition of zirconia (max. by a factor 2.5). The C 1 0 + selectivity increased with the addition of zirconia (from 42.3% in unpromoted catalyst to 68.8 % in the 20 % ZrO 2 promoted. This can be attributed to the higher amount of the surface Cobalt metal present and to the larger Cobalt particle size

  19. Iron catalyst for preparation of polymethylene from synthesis gas and method for producing the catalyst

    Science.gov (United States)

    Sapienza, R.S.; Slegeir, W.A.

    1990-05-15

    This invention relates to a process for synthesizing hydrocarbons; more particularly, the invention relates to a process for synthesizing long-chain hydrocarbons known as polymethylene from carbon monoxide and hydrogen or from carbon monoxide and water or mixtures thereof in the presence of a catalyst comprising iron and platinum or palladium or mixtures thereof which may be supported on a solid material, preferably an inorganic refractory oxide. This process may be used to convert a carbon monoxide containing gas to a product which could substitute for high density polyethylene.

  20. Monodisperse metal nanoparticle catalysts on silica mesoporous supports: synthesis, characterizations, and catalytic reactions

    Energy Technology Data Exchange (ETDEWEB)

    Somorjai, G.A.

    2009-09-14

    The design of high performance catalyst achieving near 100% product selectivity at maximum activity is one of the most important goals in the modern catalytic science research. To this end, the preparation of model catalysts whose catalytic performances can be predicted in a systematic and rational manner is of significant importance, which thereby allows understanding of the molecular ingredients affecting the catalytic performances. We have designed novel 3-dimensional (3D) high surface area model catalysts by the integration of colloidal metal nanoparticles and mesoporous silica supports. Monodisperse colloidal metal NPs with controllable size and shape were synthesized using dendrimers, polymers, or surfactants as the surface stabilizers. The size of Pt, and Rh nanoparticles can be varied from sub 1 nm to 15 nm, while the shape of Pt can be controlled to cube, cuboctahedron, and octahedron. The 3D model catalysts were generated by the incorporation of metal nanoparticles into the pores of mesoporous silica supports via two methods: capillary inclusion (CI) and nanoparticle encapsulation (NE). The former method relies on the sonication-induced inclusion of metal nanoparticles into the pores of mesoporous silica, whereas the latter is performed by the encapsulation of metal nanoparticles during the hydrothermal synthesis of mesoporous silica. The 3D model catalysts were comprehensively characterized by a variety of physical and chemical methods. These catalysts were found to show structure sensitivity in hydrocarbon conversion reactions. The Pt NPs supported on mesoporous SBA-15 silica (Pt/SBA-15) displayed significant particle size sensitivity in ethane hydrogenolysis over the size range of 1-7 nm. The Pt/SBA-15 catalysts also exhibited particle size dependent product selectivity in cyclohexene hydrogenation, crotonaldehyde hydrogenation, and pyrrole hydrogenation. The Rh loaded SBA-15 silica catalyst showed structure sensitivity in CO oxidation reaction. In

  1. Ultrasound assisted synthesis of iron doped TiO2 catalyst.

    Science.gov (United States)

    Ambati, Rohini; Gogate, Parag R

    2018-01-01

    The present work deals with synthesis of Fe (III) doped TiO 2 catalyst using the ultrasound assisted approach and conventional sol-gel approach with an objective of establishing the process intensification benefits. Effect of operating parameters such as Fe doping, type of solvent, solvent to precursor ratio and initial temperature has been investigated to get the best catalyst with minimum particle size. Comparison of the catalysts obtained using the conventional and ultrasound assisted approach under the optimized conditions has been performed using the characterization techniques like DLS, XRD, BET, SEM, EDS, TEM, FTIR and UV-Vis band gap analysis. It was established that catalyst synthesized by ultrasound assisted approach under optimized conditions of 0.4mol% doping, irradiation time of 60min, propan-2-ol as the solvent with the solvent to precursor ratio as 10 and initial temperature of 30°C was the best one with minimum particle size as 99nm and surface area as 49.41m 2 /g. SEM analysis, XRD analysis as well as the TEM analysis also confirmed the superiority of the catalyst obtained using ultrasound assisted approach as compared to the conventional approach. EDS analysis also confirmed the presence of 4.05mol% of Fe element in the sample of 0.4mol% iron doped TiO 2 . UV-Vis band gap results showed the reduction in band gap from 3.2eV to 2.9eV. Photocatalytic experiments performed to check the activity also confirmed that ultrasonically synthesized Fe doped TiO 2 catalyst resulted in a higher degradation of Acid Blue 80 as 38% while the conventionally synthesized catalyst resulted in a degradation of 31.1%. Overall, the work has clearly established importance of ultrasound in giving better catalyst characteristics as well as activity for degradation of the Acid Blue 80 dye. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Use of Graphite Oxide and Graphene Oxide as Catalysts in the Synthesis of Dipyrromethane and Calix[4]pyrrole

    Directory of Open Access Journals (Sweden)

    Sweta Mishra

    2011-08-01

    Full Text Available Graphite oxide and graphene oxides have been used as solid catalysts for the synthesis of 5,5-dialkyldipyrromethanes and calix[4]pyrroles in organic and aqueous solutions at room temperature.

  3. Application of Heteropoly Acids as Heterogeneous and Recyclable Catalysts for Friedländer Synthesis of Quinolines

    Directory of Open Access Journals (Sweden)

    Majid M. Heravi

    2010-01-01

    Full Text Available New convenient conditions for the Friedländer synthesis of quinolines are described. Quinolines were readily prepared in the presence of heteropolyacids as heterogeneous and recyclable catalysts in good yields.

  4. The formation and influence of carbon on cobalt-based Fischer-Tropsch synthesis catalysts : an integrated review

    NARCIS (Netherlands)

    Moodley, D.J.; Loosdrecht, van de J.; Saib, A.M.; Niemantsverdriet, J.W.; Davis, B.H.; Occelli, M.L.; Speight, J.G.

    2010-01-01

    Cobalt-based Fischer-Tropsch synthesis (FTS) catalysts are the systems of choice for use in gas-to-liquid (GTL) processes. As with most catalysts, cobalt systems gradually lose their activity with increasing time on stream. There are various mechanisms that have been proposed for the deactivation of

  5. Zirconyl (IV Nitrate as Efficient and Reusable Solid Lewis Acid Catalyst for the Synthesis of Benzimidazole Derivatives

    Directory of Open Access Journals (Sweden)

    Pratapsinha B. Gorepatil

    2013-01-01

    Full Text Available The present paper introduces a simple and efficient method for the synthesis of substituted benzimidazoles by heterocyclization of different o-phenylenediamines and substituted aromatic carboxylic acid/aldehyde in the presence of zirconyl nitrate as catalyst in ethanol under reflux, which produced excellent yield of corresponding benzimidazoles in a short reaction time with reusability of catalyst.

  6. The nature of the potassium compound acting as a promoter in iron-alumina catalysts for ammonia synthesis

    NARCIS (Netherlands)

    van Ommen, J.G.; Bolink, W.J.; Prasad, J.; Mars, P.

    1975-01-01

    The chemical form of the potassium promoter on an iron-alumina catalyst during ammonia synthesis has been studied by two methods, viz, (i) the measurement of the equilibrium constant of the process KNH2 + H2 KH + NH3, and (ii) chemical analysis of the used catalyst. The equilibrium constant

  7. Immobilization of isolated FI catalyst on polyhedral oligomeric silsesquioxane-functionalized silica for the synthesis of weakly entangled polyethylene.

    Science.gov (United States)

    Li, Wei; Yang, Huaqin; Zhang, Jingjing; Mu, Jingshan; Gong, Dirong; Wang, Xiaodong

    2016-09-25

    Polyhedral oligomeric silsesquioxanes (POSSs) were adsorbed on methylaluminoxane-activated silica for the immobilization of fluorinated bis(phenoxyimine)Ti complexes (FI catalyst). These POSSs have been characterized as horizontal spacers isolating the active sites and hindering the chain overlap in polymerization. The heterogeneous catalyst exhibits considerable activity in the synthesis of weakly entangled polyethylene.

  8. An Efficient Catalyst for the Synthesis of Schiff Bases

    International Nuclear Information System (INIS)

    Fareed, G.; Afza, N.; Kalhoro, M.A.

    2013-01-01

    An efficient high yielding synthesis of Schiff bases (1-17) is derived from condensation of 2-fluorenamine and 4-amino phenol with a variety of aldehydes catalyzed by dodecatungstosilicic acid P/sub 2/O/sub 5/ under solvent free conditions at room temperature. The catayst is found to be more efficient in terms of ease of reaction workup and high yields. This methodology contributes to an energy efficient, facile and environamental friendly synthesis for the preparation of Schiff bases. The structures of afforded Schiff bases were characterized by spectroscopic data and elemental analysis. (author)

  9. Activation of a Cu/ZnO catalyst for methanol synthesis

    DEFF Research Database (Denmark)

    Andreasen, Jens Wenzel; Rasmussen, F.B.; Helveg, S.

    2006-01-01

    The structural changes during activation by temperature-programmed reduction of a Cu/ZnO catalyst for methanol synthesis have been studied by several in situ techniques. The catalyst is prepared by coprecipitation and contains 4.76 wt% Cu, which forms a substitutional solid solution with Zn......O as determined by resonant X-ray diffraction. In situ resonant X-ray diffraction reveals that the Cu atoms are extracted from the solid solution by the reduction procedure, forming metallic Cu crystallites. Cu is redispersed in bulk or surface Zn lattice sites upon oxidation by heating in air. The results...... is highly dispersed and in intimate contact with the surface of the host ZnO particles. The possibility of re-forming the (Zn,Cu)O solid solution by oxidation may provide a means of redispersing Cu in a deactivated catalyst....

  10. Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis

    Directory of Open Access Journals (Sweden)

    Muhammad Faizan Shareef

    2017-10-01

    Full Text Available This paper presents the effect of a synthesis method for cobalt catalyst supported on hydrotalcite material for Fischer-Tropsch synthesis. The hydrotalcite supported cobalt (HT-Co catalysts were synthesized by co-precipitation and hydrothermal method. The prepared catalysts were characterized by using various techniques like BET (Brunauer–Emmett–Teller, SEM (Scanning Electron Microscopy, TGA (Thermal Gravimetric Analysis, XRD (X-ray diffraction spectroscopy, and FTIR (Fourier Transform Infrared Spectroscopy. Fixed bed micro reactor was used to test the catalytic activity of prepared catalysts. The catalytic testing results demonstrated the performance of hydrotalcite based cobalt catalyst in Fischer-Tropsch synthesis with high selectivity for liquid products. The effect of synthesis method on the activity and selectivity of catalyst was also discussed. Copyright © 2017 BCREC Group. All rights reserved Received: 3rd November 2016; Revised: 26th February 2017; Accepted: 9th March 2017; Available online: 27th October 2017; Published regularly: December 2017 How to Cite: Sharif, M.S., Arslan, M., Iqbal, N., Ahmad, N., Noor, T. (2017. Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis. Bulletin of Chemical Reaction Engineering & Catalysis, 12(3: 357-363 (doi:10.9767/bcrec.12.3.762.357-363

  11. Towards Green Cyclic Carbonate Synthesis : Heterogeneous and Homogeneous Catalyst Development

    NARCIS (Netherlands)

    Stewart, J.A.

    2015-01-01

    This PhD research serves to implement both known and novel catalytic systems for the purpose of cyclic carbonate synthesis from biomass-derived substrates. Such products have been earmarked as potential monomers for non-isocyanate polyurethanes (NIPUs), amongst other uses. Particular attention has

  12. The catalystic asymmetric synthesis of optically active epoxy ketones

    NARCIS (Netherlands)

    Marsman, Bertha Gerda

    1981-01-01

    In this thesis the use of catalytic asymmetric synthesis to prepare optically active epoxy ketones is described. This means that the auxiliary chirality, necessary to obtain an optically active product, is added in a catalytic quantity . In principle this is a very efficient way to make opticlly

  13. A catalyst-free synthesis of germanium nanowires obtained by ...

    Indian Academy of Sciences (India)

    2015-08-25

    Aug 25, 2015 ... 1Dipartimento di Chimica and NIS Centre of Excellence, Università degli Studi di Torino, via Pietro Giuria 7, ..... Indeed, a test synthesis replying .... 48 5446. [27] Lu X T, Harris J T, Villareal J E, Chockla A M and Korgel B.

  14. Prospects of Fe/MCM-41 as a Catalyst for Hydrocarbon Synthesis

    International Nuclear Information System (INIS)

    Cagnoli, Maria V.; Gallegos, Norma G.; Bengoa, Jose F.; Alvarez, Ana M.; Marchetti, Sergio G.; Moreno, Sergio M. J.; Roig, Anna; Mercader, Roberto C.

    2005-01-01

    We report the synthesis of cylindrical nanoparticles of metallic Fe entirely included in MCM-41 pores. Their dimensions are approx.3 nm diameter and approx. 3.8 nm length. We show that a coherent analysis of the results yielded by the various techniques is essential to obtain a catalyst supported on an MCM-41 matrix of ≅ 3 nm average pore diameter, which is active and selective toward olefins. The solids were characterized by low-angle x-ray diffraction, high-resolution transmission electron microscopy, high-resolution scanning transmission electron microscopy equipped with a high-angle annular dark-field, CO chemisorption, volumetric oxidation, and Moessbauer spectroscopy (in controlled atmosphere for the reduced catalysts). Catalytic results in the Fischer-Tropsch synthesis, as well as some unexpected results --like the inhomogeneous pore filling and discontinuous Fe particles-- are also discussed

  15. Catalyst synthesis PD/SiO2 and PD/C by irradiation microwave method

    International Nuclear Information System (INIS)

    Sant'Anna, L.S.; Franceschi, E.; Egues, S.; Santos, M.L.; Dariva, C.; Borges, G.R.

    2016-01-01

    The synthesis of nanoparticulate materials has been developed over the years, in order to propose new routes or routes more efficient in the process. The application of microwave irradiation applied in this work allowed to show that metal catalysts may be generated in a faster reaction time compared to conventional mechanical agitation techniques. Catalysts using palladium acetate (OAc) 2 supported on charcoal and commercial silica were synthesized. The solvent used for the preparation was 40 ml of ethanol at a temperature of 100 ° C and 300 W power. The synthesis time was 2 to 5 minutes. The synthesized material was calcined and characterized by ICP, XRD, TEM and BET obtained metal content ranged from 1.1 to 4.1% of the metal support. The particle size was between 7 and 9 nm. The surface areas of the carriers were reduced on its surface due to the metal impregnation. (author)

  16. Morphology Changes of Co Catalyst Nanoparticles at the Onset of Fischer-Tropsch Synthesis

    DEFF Research Database (Denmark)

    Høydalsvik, Kristin; Fløystad, Jostein B.; Voronov, Alexey

    2014-01-01

    Cobalt nanoparticles play an important role as catalysts for the Fischer-Tropsch synthesis, which is an attractive route for production of synthetic fuels. It is of particular interest to understand the varying conversion rate during the first hours after introducing synthesis gas (H-2 and CO......) to the system. To this end, several in situ characterization studies have previously been done on both idealized model systems and commercially relevant catalyst nanoparticles, using bulk techniques, such as X-ray powder diffraction and X-ray absorption spectroscopy. Since catalysis takes place at the surface...... of the cobalt particles, it is important to develop methods to gain surface-specific structural information under realistic processing conditions. We addressed this challenge using small-angle X-ray scattering (SAXS), a technique exploiting the penetrating nature of X-rays to provide information about particle...

  17. Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry.

    Science.gov (United States)

    Hiebler, Katharina; Lichtenegger, Georg J; Maier, Manuel C; Park, Eun Sung; Gonzales-Groom, Renie; Binks, Bernard P; Gruber-Woelfler, Heidrun

    2018-01-01

    Within the "compartmentalised smart factory" approach of the ONE-FLOW project the implementation of different catalysts in "compartments" provided by Pickering emulsions and their application in continuous flow is targeted. We present here the development of heterogeneous Pd catalysts that are ready to be used in combination with biocatalysts for catalytic cascade synthesis of active pharmaceutical ingredients (APIs). In particular, we focus on the application of the catalytic systems for Suzuki-Miyaura cross-coupling reactions, which is the key step in the synthesis of the targeted APIs valsartan and sacubitril. An immobilised enzyme will accomplish the final product formation via hydrolysis. In order to create a large interfacial area for the catalytic reactions and to keep the reagents separated until required, the catalyst particles are used to stabilise Pickering emulsions of oil and water. A set of Ce-Sn-Pd oxides with the molecular formula Ce 0.99- x Sn x Pd 0.01 O 2-δ ( x = 0-0.99) has been prepared utilising a simple single-step solution combustion method. The high applicability of the catalysts for different functional groups and their minimal leaching behaviour is demonstrated with various Suzuki-Miyaura cross-coupling reactions in batch as well as in continuous flow employing the so-called "plug & play reactor". Finally, we demonstrate the use of these particles as the sole emulsifier of oil-water emulsions for a range of oils.

  18. Effects of Weight Hourly Space Velocity and Catalyst Diameter on Performance of Hybrid Catalytic-Plasma Reactor for Biodiesel Synthesis over Sulphated Zinc Oxide Acid Catalyst

    Directory of Open Access Journals (Sweden)

    Luqman Buchori

    2017-05-01

    Full Text Available Biodiesel synthesis through transesterification of soybean oil with methanol on hybrid catalytic-plasma reactor over sulphated zinc oxide (SO42-/ZnO active acid catalyst was investigated. This research was aimed to study effects of Weight Hourly Space Velocity (WHSV and the catalyst diameter on performance of the hybrid catalytic-plasma reactor for biodiesel synthesis. The amount (20.2 g of active sulphated zinc oxide solid acid catalysts was loaded into discharge zone of the reactor. The WHSV and the catalyst diameter were varied between 0.89 to 1.55 min-1 and 3, 5, and 7 mm, respectively. The molar ratio of methanol to oil as reactants of 15:1 is fed to the reactor, while operating condition of the reactor was kept at reaction temperature of 65 oC and ambient pressure. The fatty acid methyl ester (FAME component in biodiesel product was identified by Gas Chromatography - Mass Spectrometry (GC-MS. The results showed that the FAME yield decreases with increasing WHSV. It was found that the optimum FAME yield was achieved of 56.91 % at WHSV of 0.89 min-1 and catalyst diameter of 5 mm and reaction time of 1.25 min. It can be concluded that the biodiesel synthesis using the hybrid catalytic-plasma reactor system exhibited promising the FAME yield. Copyright © 2017 BCREC Group. All rights reserved Received: 15th November 2016; Revised: 24th December 2016; Accepted: 16th February 2017 How to Cite: Buchori, L., Istadi, I., Purwanto, P. (2017. Effects of Weight Hourly Space Velocity and Catalyst Diameter on Performance of Hybrid Catalytic-Plasma Reactor for Biodiesel Synthesis over Sulphated Zinc Oxide Acid Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (2: 227-234 (doi:10.9767/bcrec.12.2.775.227-234 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.2.775.227-234

  19. Influence of Reduction Promoters on Stability of Cobalt/g-Alumina Fischer-Tropsch Synthesis Catalysts

    OpenAIRE

    Gary Jacobs; Wenping Ma; Burtron H. Davis

    2014-01-01

    This focused review article underscores how metal reduction promoters can impact deactivation phenomena associated with cobalt Fischer-Tropsch synthesis catalysts. Promoters can exacerbate sintering if the additional cobalt metal clusters, formed as a result of the promoting effect, are in close proximity at the nanoscale to other cobalt particles on the surface. Recent efforts have shown that when promoters are used to facilitate the reduction of small crystallites with the aim of increasing...

  20. Fischer-Tropsch Synthesis on Multicomponent Catalysts: What Can We Learn from Computer Simulations?

    OpenAIRE

    Fajin, Jose L. C.; Cordeiro, M. Natalia D. S.; Gomes, Jose R. B.

    2015-01-01

    In this concise review paper, we will address recent studies based on the generalized-gradient approximation (GGA) of the density functional theory (DFT) and on the periodic slab approach devoted to the understanding of the Fischer-Tropsch synthesis process on transition metal catalysts. As it will be seen, this computational combination arises as a very adequate strategy for the study of the reaction mechanisms on transition metal surfaces under well-controlled conditions and allows separati...

  1. Lanthanide alkyl and silyl compounds: Synthesis, reactivity and catalysts for green

    Energy Technology Data Exchange (ETDEWEB)

    Pindwal, Aradhana [Iowa State Univ., Ames, IA (United States)

    2016-01-01

    The last few decades have witnessed enormous research in the field of organometallic lanthanide chemistry. Our research group has developed a few rare earth alkyl compounds containing tris(dimethylsilyl)methyl ligand and explored their reactivity. This thesis focusses on extending the study of lanthanide alkyl and silyl compounds to develop strategies for their synthesis and explore their reactivity and role as catalysts in processes such as hydrosilylation and cross-dehydrocoupling.

  2. Synthesis of Hydrocarbons from H2-Deficient Syngas in Fischer-Tropsch Synthesis over Co-Based Catalyst Coupled with Fe-Based Catalyst as Water-Gas Shift Reaction

    Directory of Open Access Journals (Sweden)

    Ting Ma

    2015-01-01

    Full Text Available The effects of metal species in an Fe-based catalyst on structural properties were investigated through the synthesis of Fe-based catalysts containing various metal species such, as Mn, Zr, and Ce. The addition of the metal species to the Fe-based catalyst resulted in high dispersions of the Fe species and high surface areas due to the formation of mesoporous voids about 2–4 nm surrounded by the catalyst particles. The metal-added Fe-based catalysts were employed together with Co-loaded beta zeolite for the synthesis of hydrocarbons from syngas with a lower H2/CO ratio of 1 than the stoichiometric H2/CO ratio of 2 for the Fischer-Tropsch synthesis (FTS. Among the catalysts, the Mn-added Fe-based catalyst exhibited a high activity for the water-gas shift (WGS reaction with a comparative durability, leading to the enhancement of the CO hydrogenation in the FTS in comparison with Co-loaded beta zeolite alone. Furthermore, the loading of Pd on the Mn-added Fe-based catalyst enhanced the catalytic durability due to the hydrogenation of carbonaceous species by the hydrogen activated over Pd.

  3. Environmental Transmission Electron Microscopy of catalysts for the methanol synthesis

    DEFF Research Database (Denmark)

    Duchstein, Linus Daniel Leonhard

    Everywhere around the world, natural resources like crude oil are becoming less and harder to extract. It is therefore necessary to find alternatives to secure our future transportation in a sustainable way. This can be done e.g. through chemical conversion of lignocelluloses into bio...... and the reaction of the catalysts as they were happening and study crystal phase changes as well as chemical shifts because the instruments are capable of introducing gases around the sample while still maintaining their investigation properties. It could be shown, that NiGa forms Ni5Ga3nanoparticles while Cu...... to scale with the beam current density but foremost with the exposure time. The ETEM shows phase and chemical changes during the reaction....

  4. Selective conversion of synthesis gas into C2-oxygenated products using mixed-metal homogeneous catalysts

    International Nuclear Information System (INIS)

    Whyman, R.

    1986-01-01

    A feature which is a key to any wider utilization of chemistry based on synthesis gas is an understanding of, and more particularly, an ability to control, those factors which determine the selectivity of the C 1 to C 2 transformation during the hydrogenation of carbon monoxide. With the exception of the rhodium-catalyzed conversion of carbon monoxide and hydrogen into ethylene glycol and methanol, in which molar ethylene glycol/methanol selectivities of ca 2/1 may be achieved, other catalyst systems containing metals such as cobalt or ruthenium exhibit only poor selectivities to ethylene glycol. The initial studies in this area were based on the reasoning that, since the reduction of carbon monoxide to C 2 products is a complex, multi-step process, the use of appropriate combinations of metals could generate synergistic effects which might prove more effective (in terms of both catalytic activity and selectivity) than simply the sum of the individual metal components. In particular, the concept of the combination of a good hydrogenation catalyst with a good carbonylation, or ''CO insertion'', catalyst seemed particularly germane. As a result of this approach the authors discovered an unprecedented example of the effect of catalyst promoters, particularly in the enhancement of C 2 /C 1 selectivity, and one which has led to the development of composite mixed-metal homogeneous catalyst systems for the conversion of CO/H 2 into C 2 -oxygenate esters

  5. Synthesis of Dicyclopentadiene Oligomer Over Nanoporous Al-MCM-41 Catalysts.

    Science.gov (United States)

    Park, Eunseo; Kim, Jinhan; Yim, Jin-Heong; Han, Jeongsik; Kwon, Tae Soo; Park, Y K; Jeon, Jong-Ki

    2016-05-01

    One step reaction composed of DCPD oligomerization and DCPD oligomer isomerization was investigated over nanoporous Al-MCM-41 catalysts. The effects of aluminum grafting over MCM-41 on the catalyst characteristics were studied with respect to the synthesis of TCPD isomer. Physical and chemical properties of the catalysts were analyzed by N2 adsorption, temperature-programmed desorption of ammonia, and infrared spectroscopy of adsorbed pyridine. The overall number of acid sites as well as the number of Lewis acid sites increased with increasing of aluminum content over MCM-41. When utilizing MCM-41 and Al-MCM-41 as the catalyst, DCPD oligomerization reaction activity greatly increased compared to the thermal reaction. The highest TCPD isomer selectivity over the Al-MCM-41 catalyst with the highest aluminum content could be ascribed to the largest amount of acid sites. This study showed an increased level of TCPD isomer selectivity by an increasing level of Lewis acid sites through aluminum addition over MCM-41.

  6. Green Biodiesel Synthesis Using Waste Shells as Sustainable Catalysts with Camelina sativa Oil

    Directory of Open Access Journals (Sweden)

    Yelda Hangun-Balkir

    2016-01-01

    Full Text Available Waste utilization is an essential component of sustainable development and waste shells are rarely used to generate practical products and processes. Most waste shells are CaCO3 rich, which are converted to CaO once calcined and can be employed as inexpensive and green catalysts for the synthesis of biodiesel. Herein, we utilized lobster and eggshells as green catalysts for the transesterification of Camelina sativa oil as feedstock into biodiesel. Camelina sativa oil is an appealing crop option as feedstock for biodiesel production because it has high tolerance of cold weather, drought, and low-quality soils and contains approximately 40% oil content. The catalysts from waste shells were characterized by X-ray powder diffraction, Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscope. The product, biodiesel, was studied by 1H NMR and FTIR spectroscopy. The effects of methanol to oil ratio, reaction time, reaction temperature, and catalyst concentration were investigated. Optimum biodiesel yields were attained at a 12 : 1 (alcohol : oil molar ratio with 1 wt.% heterogeneous catalysts in 3 hours at 65°C. The experimental results exhibited a first-order kinetics and rate constants and activation energy were calculated for the transesterification reaction at different temperatures. The fuel properties of the biodiesel produced from Camelina sativa oil and waste shells were compared with those of the petroleum-based diesel by using American Society for Testing and Materials (ASTM standards.

  7. Synthesis and characterization of Cu-MFI catalyst for the direct medium temperature range NO decomposition

    Directory of Open Access Journals (Sweden)

    Valkaj Karolina Maduna

    2016-03-01

    Full Text Available In this study the physico-chemical and catalytic properties of copper bearing MFI zeolites (Cu-MFI with different Si/Al and Si/Cu ratios were investigated. Two different methods for incorporation of metal ions into the zeolite framework were used: the ion exchange from the solution of copper acetate and the direct hydrothermal synthesis. Direct synthesis of a zeolite in the presence of copper-phosphate complexes was expected to generate more active copper species necessary for the desired reaction than the conventional ion exchange method. Direct decomposition of NO was used as a model reaction, because this reaction still offers a very attractive approach to NOX removal. The catalytic properties of zeolite samples were studied using techniques, such as XRD, SEM, EPR and nitrogen adsorption/desorption measurements at 77 K. Results of the kinetic investigation revealed that both methods are applicable for the preparation of the catalysts with active sites capable of catalyzing the NO decomposition. It was found out that Cu-MFI zeolites obtained through direct synthesis are promising catalysts for NO decomposition, especially at lower reaction temperatures. The efficiency of the catalysts prepared by both methods is compared and discussed.

  8. Cesium Carbonate as a Heterogeneous Base Catalyst for Synthesis of 2-Aminothiophenes via Gewald Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Moeinpour, Farid [Islamic Azad University, Bandar Abbas Branch, Abbas (Iran, Islamic Republic of); Omidinia, Raheleh; Dorostkar-Ahmadi, Nadieh; Khoshdeli, Bentalhoda [Islamic Azad University, Mashhad Branch, Mashhad (Iran, Islamic Republic of)

    2011-06-15

    We have reported a new simple catalytic method for the synthesis of 2-aminothiophenes via Gewald reaction using Cs{sub 2}CO{sub 3} as an efficient, reusable and green heterogeneous catalyst under heating conditions in refluxing ethanol. The catalyst could be recycled after a simple workup and reused at least three runs without appreciable reduction in its catalytic activity. Low catalyst loading, clean reaction profiles, simple experimental and workup procedures and high yields are some advantages of this protocol. The synthesis of substituted 2-aminothiophenes is attractive to chemical researchers as they are important intermediates in organic synthesis and frequently used as the scaffold motif of a variety of agrochemicals, dyes, and biologically active products. Thus, because of their wide utility, researchers have synthesized the substituted 2-aminothiophenes via efficient and convenient methods. The one-pot cyclocondensation of ketones with an activated α-hydrogen, a cyanomethylene containing an electron-withdrawing group such as cyanoacetate and elemental sulfur in the presence of organic base, for example, morpholine, diethylamine, etc, known as the Gewald reaction, has been one of the most well-studied multicomponent reactions in recent years. To extend the scope of the reaction, many alterations have been made to the original Gewald's base-catalyzed, two-component combination of α-mercapto ketones with cyanoacetate by varying the components and the conditions.

  9. Synthesis of thin films and materials utilizing a gaseous catalyst

    Science.gov (United States)

    Morse, Daniel E; Schwenzer, Birgit; Gomm, John R; Roth, Kristian M; Heiken, Brandon; Brutchey, Richard

    2013-10-29

    A method for the fabrication of nanostructured semiconducting, photoconductive, photovoltaic, optoelectronic and electrical battery thin films and materials at low temperature, with no molecular template and no organic contaminants. High-quality metal oxide semiconductor, photovoltaic and optoelectronic materials can be fabricated with nanometer-scale dimensions and high dopant densities through the use of low-temperature biologically inspired synthesis routes, without the use of any biological or biochemical templates.

  10. Polyol Synthesis of Cobalt–Copper Alloy Catalysts for Higher Alcohol Synthesis from Syngas

    DEFF Research Database (Denmark)

    Mendes, Laiza V.P.; Snider, Jonathan L.; Fleischman, Samuel D.

    2017-01-01

    Novel catalysts for the selective production of higher alcohols from syngas could offer improved pathways towards synthetic fuels and chemicals. Cobalt–copper alloy catalysts have shown promising results for this reaction. To improve control over particle properties, a liquid phase nanoparticle s...

  11. A general protocol for the synthesis of Pt-Sn/C catalysts for the ethanol electrooxidation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B.; Lee, Z.Y.; Cheng, C.H.; Lee, J.Y. [Chemical and Biomolecular Engineering, National University of Singapore (Singapore); Chia, Z.W. [NUS Graduate School for Integrative Sciences and Engineering (NGS), Centre for Life Sciences (CeLS), Singapore (Singapore); Liu, Z.L. [Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602 (Singapore)

    2012-08-15

    A general protocol for the synthesis of Pt-Sn/C catalysts for ethanol electrooxidation by the polyol method is developed after a systematic variation of the preparation variables. This protocol enables the complete transfer of all catalytic elements in the preparation solution to the catalyst support; thereby providing a convenient means of catalyst composition control. Water is a necessary co-solvent for ethylene glycol in the polyol synthesis of Pt-Sn/C catalysts. The best preparation medium for controlling the particle size to small sizes is 0.1 M NaOH solution in a mixture of equal volumes of water and ethylene glycol. With this medium composition Pt-Sn/C catalysts with the optimized target Pt:Sn atomic ratio of 3:1 could be expeditiously prepared for ethanol electrooxidation. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Towards ‘greener’ catalyst manufacture: Reduction of wastewater from the preparation of Cu/ZnO/Al2O3 methanol synthesis catalysts

    NARCIS (Netherlands)

    Prieto, G.; de Jong, K.P.; de Jongh, P.E.

    2013-01-01

    The generation of large volumes of nitrate-containing wastewater is a major issue in the industrial production of solid catalysts such as Cu/ZnO/Al2O3 employed in methanol synthesis. Extensive washing with water is needed to remove nitrate (and sodium) residues in the as-precipitated metal

  13. Synthesis of Ni-Pt catalysts and characterization

    International Nuclear Information System (INIS)

    Santos, Everton R.F. dos; Sousa, Bianca Viana de; Barbosa, Antonielly dos Santos; Leite, Romulo C.N.; Rodrigues, Meiry G.F.

    2009-01-01

    In this work, bifunctionals catalysts using the MCM-22 zeolite as support and the nickel and platinum metal as hydrogenation/dehydrogenation sites were prepared. The method used for metal dispersion on the zeolite was the competitive ion exchange, using the amine complex [Pt(NH 3 ) 4 ]Cl 2 and [Ni(NH 3 ) 6 ]Cl 2 . After the exchange reactions, the samples were calcinated at 500 deg C for 2 hours and reduced at this same temperature under hydrogen flow. The MCM-22 zeolite and samples containing the metal were characterized by the techniques of: EDX, XRD, DTA/TGA. The diffractions of the precursor MCM-22 (P) presented typical peaks of the MWW topology composed by intercalated lamellar layers with organic molecules that are constituents of the template (HMI). According to the XRD pattern of the calcinated sample, no peaks related to the organic material which is responsible to produce the MCM-22 zeolite were detected. By thermogravimetry it was verified that the removal of the template took place between 500 and 650 deg C proving the effectiveness of the removal process. The chemical analysis by X-ray spectrometric was evidenced this the incorporation in the zeolites of platinum and nickel for all the texts in study. Results from XRD confirming the stability and crystal in study of zeolites. (author)

  14. Synthesis H-Zeolite catalyst by impregnation KI/KIO3 and performance test catalyst for biodiesel production

    Science.gov (United States)

    Widayat, W.; Rizky Wicaksono, Adit; Hakim Firdaus, Lukman; Okvitarini, Ndaru

    2016-02-01

    The objective of this research is to produce H-catalyst catalyst that was impregnated with KI/KIO3. The catalyst was analyzed about surface area, X-Ray Diffraction (XRD) and performance test of catalyst for biodiesel production. An H-Zeolite catalyst was synthesized from natural zeolite with chemical treatment processing, impregnation KI/KIO3 and physical treatment. The results shows that the surface area of the catalyst by 27.236 m2/g at a concentration of 5% KI. XRD analysis shows peak 2-θ at 23.627o indicating that KI was impregnated on H-zeolite catalyst. The catalyst was tested in production of biodiesel using palm oil with conventional methods for 3 hour at temperature of 70-80 oC. The result for conversion Fatty Acid Methyl Ester (FAME) reached maximum value on 87.91% under production process using catalyst 5% KIO3-H zeolite.

  15. A combined in situ XAS-XRPD-Raman study of Fischer-Tropsch synthesis over a carbon supported Co catalyst

    DEFF Research Database (Denmark)

    Tsakoumis, Nikolaos E.; Dehghan, Roya; Johnsen, Rune

    2013-01-01

    A cobalt based Fischer-Tropsch synthesis (FTS) catalyst, supported on a carbon nanofibers/carbon felt composite (Co/CNF/CF) was studied in situ at realistic conditions. The catalyst was monitored by Xray absorption spectroscopy (XAS), high-resolution X-ray powder diffraction (HR-XRPD) and Raman...... spectroscopy, while changes in the gas phase were observed by mass spectrometry (MS). Transmission electron microscopy (TEM) was also applied to characterise the catalyst. The catalyst has a bimodal particle size distribution and exhibits a high deactivation rate. During the in situ study the catalyst appears...... to reduce further at the induction period of FTS, while crystallite growth is been detected in the same period. At steady state FTS the amount of metallic Co is constant. A change in the volumetric flow towards higher conversions did not affect the degree of reduction or the crystallite size of the catalyst...

  16. Evidence for H2/D2 isotope effects on Fischer-Tropsch synthesis over supported ruthenium catalysts

    International Nuclear Information System (INIS)

    Kellner, C.S.; Bell, A.T.

    1981-01-01

    The effects of using D 2 rather than H 2 during Fischer-Tropsch synthesis were investigated using alumina- and silica-supported Ru catalysts. For the alumina-supported catalysts, the rate of CD 4 formation was 1.4 to 1.6 times faster than the formation of CH 4 . A noticeable isotope effect was also observed for higher molecular weight products. The magnitude of the isotope effects observed using the silica-supported catalyst was much smaller than that found using the alumina-supported catalysts. The formation of olefins relative to paraffins was found to be higher when H 2 rather than D 2 was used, independent of the catalyst support. The observed isotope effects are explained in terms of a mechanism for CO hydrogenation and are shown to arise from a complex combination of the kinetic and equilibrium isotope effects associated with elementary processes occurring on the catalyst surface

  17. Synthesis of Ni2B nanoparticles by RF thermal plasma for fuel cell catalyst

    International Nuclear Information System (INIS)

    Cheng, Y; Tanaka, M; Watanabe, T; Choi, S Y; Shin, M S; Lee, K H

    2014-01-01

    The catalyst of Ni 2 B nanoparticles was successfully prepared using nickel and boron as precursors with the quenching gas in radio frequency thermal plasmas. The generating of Ni 2 B needs adequate reaction temperature and boron content in precursors. The quenching gas is beneficial for the synthesis of Ni 2 B in RF thermal plasma. The effect of quenching rate, powder feed rate and boron content in feeding powders on the synthesis of nickel boride nanoparticles was studied in this research. The high mass fraction of 28 % of Ni 2 B nanoparticles can be generated at the fixed initial composition of Ni:B = 2:3. Quenching gas is necessary in the synthesis of Ni 2 B nanoaprticles. In addition, the mass fraction of Ni 2 B increases with the increase of quenching gas flow rate and powder feed rate

  18. Preparation and characterization of stable copper/zinc oxide/alumina catalysts for methanol synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Hoeppener, R H; Doesburg, E B; Scholten, J J

    1986-08-15

    A series of Cu/ZnO/Al/sub 2/O/sub 3/ catalysts for the low pressure methanol synthesis has been prepared by coprecipitation with a sodium carbonate solution from solutions of a mixture of the corresponding metal nitrates, followed by drying, calcination and reduction. The catalysts and their precursors were analyzed by techniques like X-ray diffraction, X-ray line broadening, differential thermal analysis, chemical analysis, adsorptive decomposition of N/sub 2/O and B.E.T.-measurements. The catalytic activity for the methanol synthesis was determined in a flow reactor under industrial conditions. Depending on the metal ion ratio in the initial metal nitrate solutions different compounds were formed during coprecipitation, like rosasite, malachite, Cu, Zn-hydrotalcite and a ternary compound which was called roderite. Its structure is unknown and it contains, besides Zn/sup 2+/, up to 28 at% Cu/sup 2+/ and up to 17 at% Al/sup 3+/. Addition of 7 at% Mg/sup 2+/ stabilizes the Cu, Zn-hydrotalcite structure but leads to a drastic decrease in catalytic activity. The rate of methanol production depends on the phase composition of the precursors. Rosasite containing precursors give the highest activity; hydrotalcite proves to be an excellent catalyst stabilizer which evokes the formation of small Cu and ZnO particles. Mg/sup 2+/ inhibits methanol production. 6 figs., 1 tab., 18 refs.

  19. Cerium Modified Pillared Montmorillonite Supported Cobalt Catalysts for Fischer Tropsch Synthesis

    International Nuclear Information System (INIS)

    Ahmad, N.; Ali, Z.; Abbas, S. M.; Hussain, F.

    2015-01-01

    Fischer-Tropsch (FT) synthesis was accomplished over Al-pillared Montmorillonite supported 20 wt% Co modified with different weight% of cerium catalysts. These catalysts were prepared by impregnation method while structural characterizations of the prepared samples were performed by XRD, TPR, NH/sub 3/TPD, TGA, BET, XRF and SEM techniques. The Fischer Tropsch reaction was studied in fixed bed micro catalytic reactor at temperature range of 220, 260 and 275 degree C and at different pressure (1, 5 and 10 bars). From the activity results, it was found that by pillaring NaMMT with Al higher catalytic activity and lower methane selectivity of NaMMT was achieved. Furthermore, the results of FT synthesis reaction revealed that cerium incorporation increased the dispersion of Co/sub 3/O/sub 4/ on the surface and consequently resulted in enhanced catalytic activity. Additionally, the C/sub 5/-C/sub 12/ hydrocarbons and methane selectivity increased while C/sub 22+/ hydrocarbons selectivity was decreased over cerium modified catalysts. Higher reaction temperature (>220 degree C) resulted in significant enhancement in CO conversion and methane selectivity. Though, increase in pressure from 1 to 10 bars eventually resulted in increase in C/sub 5+/ hydrocarbons and decrease in methane and C/sub 2/-C/sub 5/ hydrocarbons selectivity. (author)

  20. Synthesis of novel perfluoroalkylglucosides on zeolite and non-zeolite catalysts.

    Science.gov (United States)

    Nowicki, Janusz; Mokrzycki, Łukasz; Sulikowski, Bogdan

    2015-04-08

    Perfluoroalkylglucosides comprise a very important class of fluorine-containing surfactants. These compounds can be synthesized by using the Fisher reaction, starting directly from glucose and the required perfluoroalcohols. We wish to report on the use of zeolite catalysts of different structure and composition for the synthesis of perfluoroalkylglucosides when using glucose and 1-octafluoropentanol as substrates. Zeolites of different pore architecture have been chosen (ZSM-5, ZSM-12, MCM-22 and Beta). Zeolites were characterized by XRD, nitrogen sorption, scanning electron microscopy (SEM) and solid-state 27Al MAS NMR spectroscopy. The activity of the zeolite catalysts in the glycosidation reaction was studied in a batch reactor at 100 °C below atmospheric pressure. The performance of zeolites was compared to other catalysts, an ion-exchange resin (Purolite) and a montmorillonite-type layered aluminosilicate. The catalytic performance of zeolite Beta was the highest among the zeolites studied and the results were comparable to those obtained over Purolite and montmorillonite type catalysts.

  1. Synthesis, Characterization, and Use of Novel Bimetal Oxide Catalyst for Photoassisted Degradation of Malachite Green Dye

    Directory of Open Access Journals (Sweden)

    K. L. Ameta

    2014-01-01

    Full Text Available This work reports a simple, novel, and cost effective synthesis of nanobimetal oxide catalyst using cerium and cadmium nitrates as metal precursors. The cerium-cadmium oxide nanophotocatalyst was synthesized by coprecipitation method and characterized by X-ray powder diffraction method to analyze the particle size. XRD study reveals a high degree of crystallinity and 28.43 nm particle size. The photocatalytic efficiency of the synthesized nanobimetal catalyst was examined by using it for the photocatalytic degradation of malachite green dye. Experiments were conducted to study the effect of various parameters, such as the pH of the dye solution, concentration of dye, amount of catalyst, and light intensity on the rate of dye degradation. The progress of the dye degradation was monitored spectrophotometrically by taking the optical density of the dye solution at regular intervals. Experimental results indicate that the dye degrades best at pH 8.0 with light intensity 600 Wm−2 and catalyst loading 0.03 g/50 mL of dye solution. The rate constant for the reaction was 7.67 × 10−4 s−1.

  2. Fischer-Tropsch Synthesis on Multicomponent Catalysts: What Can We Learn from Computer Simulations?

    Directory of Open Access Journals (Sweden)

    José L. C. Fajín

    2015-01-01

    Full Text Available In this concise review paper, we will address recent studies based on the generalized-gradient approximation (GGA of the density functional theory (DFT and on the periodic slab approach devoted to the understanding of the Fischer-Tropsch synthesis process on transition metal catalysts. As it will be seen, this computational combination arises as a very adequate strategy for the study of the reaction mechanisms on transition metal surfaces under well-controlled conditions and allows separating the influence of different parameters, e.g., catalyst surface morphology and coverage, influence of co-adsorbates, among others, in the global catalytic processes. In fact, the computational studies can now compete with research employing modern experimental techniques since very efficient parallel computer codes and powerful computers enable the investigation of more realistic molecular systems in terms of size and composition and to explore the complexity of the potential energy surfaces connecting reactants, to intermediates, to products of reaction. In the case of the Fischer-Tropsch process, the calculations were used to complement experimental work and to clarify the reaction mechanisms on different catalyst models, as well as the influence of additional components and co-adsorbate species in catalyst activity and selectivity.

  3. Biodiesel synthesis using K2CO3/Al–O–Si aerogel catalysts

    Directory of Open Access Journals (Sweden)

    IVANA LUKIĆ

    2010-06-01

    Full Text Available In this study, catalysts for fatty acid methyl esters (FAME or bio-diesel synthesis with K2CO3 as the active component on an alumina/silica support were synthesized using the sol–gel method, which was followed by drying the “dense” wet gels with supercritical carbon dioxide to obtain the aerogels. The prepared catalysts were characterized by XRD analysis, FTIR spectroscopy and N2 physisorption at 77 K, and tested in the methanolysis of sunflower oil. The effects of reaction variables, such as reaction time, temperature and methanol to oil molar ratio, on the yield of FAME were investigated. The aerogel catalysts with K2CO3 as the active component on an alumina/silica support exhibited good activity in the methanolysis of sunflower oil. The leaching of potassium when the catalyst was in contact with pure methanol under the working conditions of methanolysis was also tested in this study, indicating that it occurred only at higher temperatures, while at lower ones, it was negligible.

  4. The study of catalysts for synthesis of higher alcohols from CO + H/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Niu Yugin; Chen Zhenghua; Liu Xiulan; Li Yu; Bo Luhong

    1988-03-01

    Catalysts for synthesis of higher alcohols from CO+H/sub 2/ were developed, and the effects of preparing methods, Zn/Cr atomic ratio and K/sub 2/0 content on catalyst activity were investigated. The effects of the technological parameters were studied. An 1000 h long term test was carried out in order to investigate the catalyst life. Experimental results show that the catalyst has high activity and selectivity, as well as good stability. In the long term test under reaction conditions of 400-405 degrees C, 14-15 MPa, 5000h/sup -1/ (with respect to exit gas), the alcohol product composition is methanol 73-75%; ethanol 1.5-2.2%; propanol 2.2-2.5%; isobutanol 15-17; isopentanol 1-1.5%, while the activity and selectivity are 0.3-0.32 ml/ml cat.h and more than 90% respectively. 5 refs., 4 figs., 2 tabs.

  5. Surface heterogeneity and ionization of Cs promoter in carbon-based ruthenium catalyst for ammonia synthesis

    International Nuclear Information System (INIS)

    Kotarba, Andrzej; Dmytrzyk, Jaromir; Rarog-Pilecka, Wioletta; Kowalczyk, Zbigniew

    2003-01-01

    Second-generation ammonia synthesis cesium-doped ruthenium catalyst supported on turbostratic carbon was investigated by the species resolved thermal alkali desorption method (SR-TAD). Energetic barriers for cesium ions (2.86 eV), ground state (1.96 eV) and electronically excited atoms (5.76 eV) desorbing from the Cs-Ru/C catalyst were determined. In the case of ruthenium-free Cs/C system, cesium desorbs as ground state atoms only, with an energy barrier of 2.87 eV. The work functions determined by the thermionic emission of electrons from Cs/C and Cs-Ru/C were of the same value (2.9 eV). It was concluded that ruthenium induces heterogeneous distribution of cesium on the catalyst surface. The promoter stability is reduced on low work function areas and its surface ionization on high work function areas opens the ionic desorption channel. The Cs desorption from the catalyst is discussed in terms of the literature data for the cesium/graphite system

  6. Synthesis of Pt/rGO catalysts with two different reducing agents and their methanol electrooxidation activity

    Energy Technology Data Exchange (ETDEWEB)

    Vu, Thu Ha Thi, E-mail: ptntd2004@yahoo.fr [Key Laboratory for Petrochemical and Refinery Technologies, 2 Pham Ngu Lao street, Hanoi (Viet Nam); Tran, Thanh Thuy Thi, E-mail: tranthithanhthuygl@gmail.com [Key Laboratory for Petrochemical and Refinery Technologies, 2 Pham Ngu Lao street, Hanoi (Viet Nam); Le, Hong Ngan Thi; Tran, Lien Thi; Nguyen, Phuong Hoa Thi; Nguyen, Minh Dang [Key Laboratory for Petrochemical and Refinery Technologies, 2 Pham Ngu Lao street, Hanoi (Viet Nam); Quynh, Bui Ngoc [Institut de recherches sur la catalyse et l’environnement de Lyon, UMR5256, 2 avenue Albert Einstein, 69626 Villeurbanne cedex (France)

    2016-01-15

    Highlights: • Pt/rGO catalysts were successfully synthesized using either NaBH{sub 4} or ethylene glycol. • Synthesis using NaBH{sub 4} could improve electrocatalytic towards methanol oxidation of Pt/rGO catalyst. • 40%Pt/rGO synthesized using NaBH{sub 4} showed the best electrocatalytic performance. - Abstract: The synthesis processes of Platinum (Pt) on reduced graphene oxide (rGO) catalysts from graphene oxide (GO) using two reducing agents including sodium borohydride and ethylene glycol is reported. Structure and morphology of Pt/rGO catalysts are characterized by X-ray powder diffraction, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrocatalytic methanol oxidation properties of these catalysts are evaluated by cyclic voltammetry and chronoamperometry. The results show that catalyst synthesized using sodium borohydride has a higher metallic Pt content and an improved catalytic performance in comparison to catalyst synthesized using ethylene glycol. Moreover, effect of Pt loading amount on electrocatalytic methanol oxidation performance of catalysts synthesized using sodium borohydride is systematically investigated. The optimal Pt loading amount on graphene is determined to be 40%.

  7. Zeolite/magnetite composites as catalysts on the Synthesis of Methyl Esters (MES) from cooking oil

    Science.gov (United States)

    Sriatun; Darmawan, Adi; Sriyanti; Cahyani, Wuri; Widyandari, Hendri

    2018-05-01

    The using of zeolite/magnetite composite as a catalyst for the synthesis of methyl esters (MES) of cooking oil has been performed. In this study the natural magnetite was extracted from the iron sand of Semarang marina beach and milled by high energy Milling (HEM) with ball: magnetite ratio: 1:1. The composites prepared from natural zeolite and natural magnetite with zeolite: magnetite ratio 1:1; 2:1; 3:1 and 4:1. Preparation of methyl ester was catalyzed by composite of zeolite/magnetite through transeserification reaction, it was studied on variation of catalyst concentration (w/v) 1%, 3%, 5% and 10% to feed volume. The reaction product are mixture of methyl Oleic (MES), methyl Palmitic (MES) and methyl Stearic (MES). Character product of this research include density, viscosity, acid number and iodine number has fulfilled to SNI standard 7182: 2015.

  8. Origin of low temperature deactivation of Ni5Ga3 nanoparticles as catalyst for methanol synthesis

    DEFF Research Database (Denmark)

    Gardini, Diego; Sharafutdinov, Irek; Damsgaard, Christian Danvad

    that the highest methanol yield is obtained with a Ni5Ga3 alloy exposed to a 25% CO2 – 75% H2 reaction mixture at 210 °C [2]. Under these experimental conditions, the catalyst is found to lose 35% of its activity after 20 hours of continuous testing at both 1 and 5 Bars. Although in situ XRD and EXAFS studies [3......In an effort to find alternative energy sources capable to compete with fossil fuels, methanol synthesis could represent a realistic solution to store “green” hydrogen produced from electrolysis or photo-induced water splitting. Recently, density functional theory (DFT) calculations [1] proposed Ni......-Ga alloys as active catalysts for methanol production from syngas mixtures and Ni-Ga nanoparticles supported on highly porous silica have been prepared using an incipient wetness impregnation technique from a solution of nickel and gallium nitrates [2]. Tests conducted in a fixed-bed reactor showed...

  9. Catalyst synthesis and evaluation using an integrated atomic layer deposition synthesis–catalysis testing tool

    International Nuclear Information System (INIS)

    Camacho-Bunquin, Jeffrey; Shou, Heng; Marshall, Christopher L.; Aich, Payoli; Beaulieu, David R.; Klotzsch, Helmut; Bachman, Stephen; Hock, Adam; Stair, Peter

    2015-01-01

    An integrated atomic layer deposition synthesis-catalysis (I-ALD-CAT) tool was developed. It combines an ALD manifold in-line with a plug-flow reactor system for the synthesis of supported catalytic materials by ALD and immediate evaluation of catalyst reactivity using gas-phase probe reactions. The I-ALD-CAT delivery system consists of 12 different metal ALD precursor channels, 4 oxidizing or reducing agents, and 4 catalytic reaction feeds to either of the two plug-flow reactors. The system can employ reactor pressures and temperatures in the range of 10 −3 to 1 bar and 300–1000 K, respectively. The instrument is also equipped with a gas chromatograph and a mass spectrometer unit for the detection and quantification of volatile species from ALD and catalytic reactions. In this report, we demonstrate the use of the I-ALD-CAT tool for the synthesis of platinum active sites and Al 2 O 3 overcoats, and evaluation of catalyst propylene hydrogenation activity

  10. Catalyst synthesis and evaluation using an integrated atomic layer deposition synthesis–catalysis testing tool

    Energy Technology Data Exchange (ETDEWEB)

    Camacho-Bunquin, Jeffrey; Shou, Heng; Marshall, Christopher L. [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Aich, Payoli [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Beaulieu, David R.; Klotzsch, Helmut; Bachman, Stephen [Arradiance Inc., Sudbury, Massachusetts 01776 (United States); Hock, Adam [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Stair, Peter [Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)

    2015-08-15

    An integrated atomic layer deposition synthesis-catalysis (I-ALD-CAT) tool was developed. It combines an ALD manifold in-line with a plug-flow reactor system for the synthesis of supported catalytic materials by ALD and immediate evaluation of catalyst reactivity using gas-phase probe reactions. The I-ALD-CAT delivery system consists of 12 different metal ALD precursor channels, 4 oxidizing or reducing agents, and 4 catalytic reaction feeds to either of the two plug-flow reactors. The system can employ reactor pressures and temperatures in the range of 10{sup −3} to 1 bar and 300–1000 K, respectively. The instrument is also equipped with a gas chromatograph and a mass spectrometer unit for the detection and quantification of volatile species from ALD and catalytic reactions. In this report, we demonstrate the use of the I-ALD-CAT tool for the synthesis of platinum active sites and Al{sub 2}O{sub 3} overcoats, and evaluation of catalyst propylene hydrogenation activity.

  11. Ammonia synthesis and decomposition on a Ru-based catalyst modeled by first-principles

    DEFF Research Database (Denmark)

    Hellman, A.; Honkala, Johanna Karoliina; Remediakis, Ioannis

    2009-01-01

    A recently published first-principles model for the ammonia synthesis on an unpromoted Ru-based catalyst is extended to also describe ammonia decomposition. In addition, further analysis concerning trends in ammonia productivity, surface conditions during the reaction, and macro-properties, such ......A recently published first-principles model for the ammonia synthesis on an unpromoted Ru-based catalyst is extended to also describe ammonia decomposition. In addition, further analysis concerning trends in ammonia productivity, surface conditions during the reaction, and macro......-properties, such as apparent activation energies and reaction orders are provided. All observed trends in activity are captured by the model and the absolute value of ammonia synthesis/decomposition productivity is predicted to within a factor of 1-100 depending on the experimental conditions. Moreover it is shown: (i......) that small changes in the relative adsorption potential energies are sufficient to get a quantitative agreement between theory and experiment (Appendix A) and (ii) that it is possible to reproduce results from the first-principles model by a simple micro-kinetic model (Appendix B)....

  12. Synthesis of a nano-crystalline solid acid catalyst from fly ash and its catalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Chitralekha Khatri; Ashu Rani [Government P.G. College, Kota (India). Environmental Chemistry Laboratory

    2008-10-15

    The synthesis of nano-crystalline activated fly ash catalyst (AFAC) with crystallite size of 12 nm was carried out by chemical and thermal treatment of fly ash, a waste material generated from coal-burning power plants. Fly ash was chemically activated using sulfuric acid followed by thermal activation at 600{sup o}C. The variation of surface and physico-chemical properties of the fly ash by activation methods resulted in improved acidity and therefore, catalytic activity for acid catalyzed reactions. The AFAC was characterized by X-ray diffraction, FT-IR spectroscopy, N{sub 2}-adsorption-desorption isotherm, scanning electron microscopy, flame atomic absorption spectrophotometry and sulfur content by CHNS/O elemental analysis. It showed amorphous nature due to high silica content (81%) and possessed high BET surface area (120 m{sup 2}/g). The catalyst was found to be highly active solid acid catalyst for liquid phase esterification of salicylic acid with acetic anhydride and methanol giving acetylsalicylic acid and methyl salicylate respectively. A maximum yield of 97% with high purity of acetylsalicylic acid (aspirin) and a very high conversion 87% of salicylic acid to methyl salicylate (oil of wintergreen) was obtained with AFAC. The surface acidity and therefore, catalytic activity in AFAC was originated by increased silica content, hydroxyl content and higher surface area as compared to fly ash. The study shows that coal generated fly ash can be converted into potential solid acid catalyst for acid catalyzed reactions. Furthermore, this catalyst may replace conventional environmentally hazardous homogeneous liquid acids making an ecofriendly; solvent free, atom efficient, solid acid based catalytic process. 27 refs., 5 figs., 2 tabs.

  13. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction. Technical progress report, October 25, 1990--October 24, 1991: Draft

    Energy Technology Data Exchange (ETDEWEB)

    Klein, M.T.

    1991-12-30

    The purpose of this work is to investigate the kinetics-assisted design, synthesis and characterization of fme-pardcle, unsupported catalysts for coal liquefaction. The goal is to develop a fundamental understanding of coal catalysis and catalysts that will, in turn, allow for the specification of a novel optimal catalyst for coal liquefaction.

  14. Amberlyst-15: An Efficient and reusable heterogeneous catalyst for the synthesis of β-amino carbonyl compounds

    Directory of Open Access Journals (Sweden)

    Pathakota Venkata Ramana

    2015-12-01

    Full Text Available A simple and efficient method has been developed for the synthesis of β-amino carbonyl compounds from aromatic ketones, aldehydes and amines by Mannich reaction in the presence of amberlyst-15 as a reusable heterogeneous catalyst at room temperature under solvent-free conditions. The noteworthy advantages of the present method are short reaction times, good product yields, simple procedures and use of non-toxic catalyst.

  15. Effect of pretreatment temperature on catalytic performance of the catalysts derived from cobalt carbonyl cluster in Fischer-Tropsch Synthesis

    Directory of Open Access Journals (Sweden)

    Byambasuren O

    2017-02-01

    Full Text Available The monometallic cobalt-based catalysts were prepared by pretreating the catalysts derived from carbonyl cluster precursor (CO6Co2CC(COOH2 supported on γ-Al2O3 with hydrogen at 180, 220, and 260°C respectively. The temperature effect of the pretreatments on the structure evolution of cluster precursors and the catalytic performance of the Fischer-Tropsch (F-T synthesis was investigated. The pretreated catalyst at 220°C with unique phase structure exhibited best catalytic activity and selectivity among three pretreated catalysts. Moreover, the catalysts exhibited high dispersion due to the formation of hydrogen bonds between the cluster precursor and γ-Al2O3 support.

  16. Synthesis of Higher Alcohols via Syngas on Cu/Zn/Si Catalysts. Effect of Polyethylene Glycol Content

    Science.gov (United States)

    Cui, Rong-Ji; Yan, Xing; Fan, Jin-Chuan; Huang, Wei

    2018-05-01

    Cu/Zn/Si catalysts with different polyethylene glycol (PEG) content were prepared by a complete liquid-phase method, and characterized by XRD, H2-TPR, N2-adsorption, and XPS. The influence of PEG content on the higher alcohols synthesis from syngas was investigated. The results showed that addition of PEG can influence the texture and surface properties of the catalysts, and therefore affect their activity and product distribution. With an increase in PEG content, BET surface area, Cu crystallite size and surface active ingredient content of the catalysts first increased and then decreased, the CO conversion had similar variation tendency. However, the pore volume and pore diameter of the catalyst increased, and the binding energy of the active component and the content of Cu2O decreased, which resulted in higher catalyst selectivity towards higher alcohols. The highest C2+OH selectivity in total alcohols was 60.6 wt %.

  17. Model studies of secondary hydrogenation in Fischer-Tropsch synthesis studied by cobalt catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Aaserud, Christian

    2003-07-01

    Mass transfer effects are very important in Fischer-Tropsch (FT) synthesis. In order to study the FT synthesis without the influence of any transport limitations, cobalt foils have been used as model catalysts. The effect of pretreatment (number of calcinations and different reduction times) for cobalt foil catalysts at 220 {sup o}C, 1 bar and H{sub 2}/CO = 3 has been studied in a microreactor. The foils were examined by Scanning electron microscopy (SEM). It was found that the catalytic activity of the cobalt foil increases with the number of pretreatments possibly due to an increase in the surface area of the cobalt foil. The SEM results support the assumption that the surface area of the cobalt foil increases with the number of pretreatments. The reduction time was also found to influence the catalytic activity of the cobalt foil. Highest activity was obtained using a reduction time of only five min (compared to one and thirty min). The decrease in activity after reduction for thirty min compared to five min was suggested to be due to restructuring of the surface of the cobalt foil and a reduction time of only 1 min was not enough to reduce the cobalt foil sufficiently. Time of reduction did also influence the product distribution. Increased reduction time resulted in a lower selectivity to light products and increased selectivity to heavier components. The paraffin/olefin ratio increased with increasing CO-conversion also for cobalt foils. The paraffin/olefin ratio also increased when the reduction period of the cobalt foil was increased at a given CO-conversion. Hydrogenation of propene to propane has been studied as a model reaction for secondary hydrogenation of olefins in the FT synthesis. The study has involved promoted and unpromoted cobalt FT catalysts supported on different types of supports and also unsupported cobalt. Hydrogenation of propene was carried out at 120 {sup o}C, 1.8 bar and H{sub 2}/C{sub 3}H{sub 6} 6 in a fixed bed microreactor. The rate

  18. Synthesis of Poly(3,4-Ethylenedioxy thiophene)-Poly(Styrene-4-Sulfonate) Composites for Support Fuel Cell Catalyst Layer

    International Nuclear Information System (INIS)

    Eko Sulistiyono; Murni Handayani

    2009-01-01

    Synthesis of poly(3,4-ethylenedioxy thiophene)-poly(styrene-4-sulfonate) composites for support fuel cell catalyst layer are synthesis composites which become fuel cell catalyst support so that catalyst has optimal performance. Main function of composites is support platinum particle for application in fuel cell. This article explains the result of composites production process from ( 3,4 Ethylenedioxy thiophene) and Sodium poly( styrene - 4-sulfonate) using two methods Jingning Shan method (method 1) and Zhigang Qi and Peter G.Pickup method (method 2). Analysis of the synthesis results used Scanning Electron Microscopic –Electron Dispersive X – Ray Spectrophotometer (SEM-EDS ). The analysis result show that both methods produce polymer agglomerate into a sponge-like morphology. Composite from method 1 has morphology, pores and proton transport better than composite produced by method 2. (author)

  19. Synthesis and Reactions of Five-Membered Heterocycles Using Phase Transfer Catalyst (PTC Techniques

    Directory of Open Access Journals (Sweden)

    Ahmed M. El-Sayed

    2014-01-01

    Full Text Available Phase transfer catalysts (PTCs have been widely used for the synthesis of organic compounds particularly in both liquid-liquid and solid-liquid heterogeneous reaction mixtures. They are known to accelerate reaction rates by facilitating formation of interphase transfer of species and making reactions between reagents in two immiscible phases possible. Application of PTC instead of traditional technologies for industrial processes of organic synthesis provides substantial benefits for the environment. On the basis of numerous reports it is evident that phase-transfer catalysis is the most efficient way for generation and reactions of many active intermediates. In this review we report various uses of PTC in syntheses and reactions of five-membered heterocycles compounds and their multifused rings.

  20. SHS-produced intermetallides as catalysts for hydrocarbons synthesis from CO and H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Eliseev, O.L.; Kazantsev, R.V.; Davydov, P.E.; Lapidus, A.L. [Russian Academy of Sciences, Moscow (Russian Federation). N.D. Zelinsky Institute of Organic Chemistry; Borshch, V.N.; Pugacheva, E.V. [Russian Academy of Sciences, Chernogolovka (Russian Federation). Inst. of Structural Macrokinetics and Materials Science

    2012-07-01

    Raney-type polymetallic alloys were prepared by Self-Propagating High-Temperature Synthesis followed by alkaline treating. Surface morphology and composition of were studied using XRD, BET, SEM and EMPA techniques. The samples were tested in Fischer-Tropsch synthesis demonstrated rather high activity and very high selectivity to heavy paraffins. High selectivity to C{sub 5+} hydrocarbons is attributed to high thermal conductivity of alloys which prevents hot spots formation and therefore suppresses formation of methane and light hydrocarbons. Selectivity can be further improved by adding some d-metals in catalyst composition. Promotion with La seems to be particularly suitable for lowering methane formation while doping with Ni enhances methane yield greatly. (orig.)

  1. Direct synthesis of iso-butane from synthesis gas or CO2 over CuZnZrAl/Pd-β hybrid catalyst

    Directory of Open Access Journals (Sweden)

    Congming Li

    2017-12-01

    Full Text Available The effect of various factors on the catalytic performance of iso-butane formation over CuZnZrAl/Pd-β hybrid catalyst via synthesis gas or CO2 hydrogenation has been deeply investigated in this work. It was interesting to note that the iso-butane/n-butane ratio value was much higher than that of thermodynamic equilibrium (about 1/1, whose value was directly related to the reaction condition using this hybrid catalyst. In order to further clearly clarify this finding, various experimental reaction factors were selected to investigate the formation of iso-butane. The results revealed that increasing temperature, H2/COx, CO2/COx, and/or Pd loading possessed an inhibiting effect on the iso-butane yield. High selectivity of iso-butane could be achieved by increasing the reaction pressure, W/F and the weight ratio of CuZnZrAl methanol catalyst to Pd-β catalyst. It is also noted that the addition of water seriously suppressed the reaction activity, resulting in the low ratio of iso-butane/n-butane. A possible reaction route was elucidated based on the latest results. This might shed light on the development of a high efficient catalyst for iso-butane production from synthesis gas or CO2 hydrogenation. Keywords: Iso-butane, Synthesis gas, CO2, CuZnZrAl/Pd-β hybrid catalyst

  2. Development and functionalization of magnetic nanoparticles as powerful and green catalysts for organic synthesis

    Directory of Open Access Journals (Sweden)

    Ahmed M. Abu-Dief

    2018-03-01

    Full Text Available Magnetic nanoparticles are a highly worthy reactant for the correlation of homogeneous inorganic and organic containing catalysts. This review deals with the very recent main advances in the development of various nano catalytic systems by the immobilization of homogeneous catalysts onto magnetic nanoparticles. Catalytic fields include the use of mainly cobalt, nickel, copper, and zinc ferrites, as well as their mixed-metal combinations with Cr, Cd, Mn and sometimes some lanthanides. The ferrite nanomaterials are obtained mainly by co-precipitation and hydrothermal methods, sometimes by the sonochemical technique, micro emulsion and flame spray synthesis route. Catalytic processes with application of ferrite nanoparticles include degradation (in particular photocatalytic, reactions of dehydrogenation, oxidation, alkylation, C–C coupling, among other processes. Ferrite nano catalysts can be easily recovered from reaction systems and reused up to several runs almost without loss of catalytic activity. Finally, we draw conclusions and present a futurity outlook for the further development of new catalytic systems which are immobilized onto magnetic nanoparticles.

  3. Silylated Co/SBA-15 catalysts for Fischer-Tropsch synthesis

    International Nuclear Information System (INIS)

    Jia Lihong; Jia Litao; Li Debao; Hou Bo; Wang Jungang; Sun Yuhan

    2011-01-01

    A series of silylated Co/SBA-15 catalysts were prepared via the reaction of surface Si-OH of SBA-15 with hexamethyldisilazane (HMDS) under anhydrous, vapor-phase conditions, and then characterized by FT-IR, N 2 physisorption, TG, XRD, and TPR-MS. The results showed that organic modification led to a silylated SBA-15 surface composed of stable hydrophobic Si-(CH 3 ) 3 species even after calcinations and H 2 reduction at 673 K. Furthermore, the hydrophobic surface strongly influenced both metal dispersion and reducibility. Compared with non-silylated Co/SBA, Co/S-SBA (impregnation after silylation) showed a high activity, due to the better cobalt reducibility on the hydrophobic support. However, S-Co/SBA (silylation after impregnation) had the lowest FT activity among all the catalysts, due to the lower cobalt reducibility along with the steric hindrance of grafted -Si(CH 3 ) 3 for the re-adsorption of α-olefins. -- Graphical abstract: The silylation of an SBA-15 before cobalt impregnation enhanced the reducibility of cobalt oxides on an SBA-15-supported cobalt catalyst and consequently increased the catalytic activity for Fischer-Tropsch synthesis. Display Omitted

  4. Hydrothermal Synthesis of Co-Ru Alloy Particle Catalysts for Hydrogen Generation from Sodium Borohydride

    Directory of Open Access Journals (Sweden)

    Marija Kurtinaitienė

    2013-01-01

    Full Text Available We report the synthesis of μm and sub-μm-sized Co, Ru, and Co-Ru alloy species by hydrothermal approach in the aqueous alkaline solutions (pH ≥ 13 containing CoCl2 and/or RuCl3, sodium citrate, and hydrazine hydrate and a study of their catalytic properties for hydrogen generation by hydrolysis of sodium borohydride solution. This way provides a simple platform for fabrication of the ball-shaped Co-Ru alloy catalysts containing up to 12 wt% Ru. Note that bimetallic Co-Ru alloy bowls containing even 7 at.% Ru have demonstrated catalytic properties that are comparable with the ones of pure Ru particles fabricated by the same method. This result is of great importance in view of the preparation of cost-efficient catalysts for hydrogen generation from borohydrides. The morphology and composition of fabricated catalyst particles have been characterized using scanning electron microscopy, energy dispersive X-ray diffraction, and inductively coupled plasma optical emission spectrometry.

  5. Synthesis, Characterizations, and Applications of Metal-Ions Incorporated High Quality MCM-41 Catalysts

    International Nuclear Information System (INIS)

    Lim, Steven S.; Haller, Gary L.

    2013-01-01

    Various metal ions (transition and base metals) incorporated MCM-41 catalysts can be synthesized using colloidal and soluble silica with non-sodium involved process. Transition metal ion-typically V 5+ , Co 2+ , and Ni 2+ -incorporated MCM-41 catalysts were synthesized by isomorphous substitution of Si ions in the framework. Each incorporated metal ion created a single species in the silica framework, single-site solid catalyst, showing a substantial stability in reduction and catalytic activity. Radius of pore curvature effect was investigated with Co-MCM-41 by temperature programmed reduction (TPR). The size of metallic Co clusters, sub-nanometer, could be controlled by a proper reduction treatment of Co-MCM-41 having different pore size and the initial pH adjustment of the Co-MCM-41 synthesis solution. These small metallic clusters showed a high stability under a harsh reaction condition without serious migration, resulting from a direct anchoring of small metallic clusters to the partially or unreduced metal ions on the surface. After a complete reduction, partial occlusion of the metallic cluster surface by amorphous silica stabilized the particles against aggregations. As a probe reaction of particle size sensitivity, carbon single wall nanotubes (SWNT) were synthesized using Co-MCM-41. A metallic cluster stability test was performed by CO methanation using Co- and Ni-MCM-41. Methanol and methane partial oxidations were carried out with V-MCM-41, and the radius of pore curvature effect on the catalytic activity was investigated

  6. Uranium sesqui nitride synthesis and its use as catalyst for the thermo decomposition of ammonia

    International Nuclear Information System (INIS)

    Rocha, Soraya Maria Rizzo da

    1996-01-01

    The preoccupation to have a secure destination for metallic uranium scraps and wastes and to search new non-nuclear uses for the huge amount of depleted metal uranium accumulated at the nuclear industry encouraged the study of the uranium sesqui nitride synthesis and its use. The use of uranium sesqui nitride as a catalyst for the thermo decomposition of ammonia for the hydrogen production has enormous significance. One of the most important nuclear cycle step is the reduction of the higher uranium oxides for the production of uranium dioxide and its conversion to uranium tetrafluoride. The reduction of the UO 3 and U 3 O 8 oxides is accomplished by the gas-solid reaction with elementary hydrogen. For economical purposes and for the safety concern the nuclear industry prefers to manufacture the hydrogen gas at the local and at the moment of use, exploring the catalytic decomposition of ammonia vapor. Using metallic uranium scraps as the raw material the obtention of its nitride was achieved by the reaction with ammonia. The results of the chemical and physical characterization of the prepared uranium sesqui nitride and its behavior as a catalyst for the cracking of ammonia are commented. A lower ammonia cracking temperature (550 deg C) using the uranium sesqui nitride compared with recommended industrial catalysts iron nitride (650 deg C) and manganese nitride (700 deg C) sounds reliable and economically advantageous. (author)

  7. Search Directions for Direct H2O2 Synthesis Catalysts Starting from Au-12 Nanoclusters

    DEFF Research Database (Denmark)

    Grabow, Lars; Larsen, Britt Hvolbæk; Falsig, Hanne

    2012-01-01

    that the rate of H2O2 and H2O formation can be determined from a single descriptor, namely, the binding energy of oxygen (E-O). Our model predicts the search direction starting from an Au-12 nanocluster for an optimal catalyst in terms of activity and selectivity for direct H2O2 synthesis. Taking also stability......We present density functional theory calculations on the direct synthesis of H2O2 from H-2 and O-2 over an Au-12 corner model of a gold nanoparticle. We first show a simple route for the direct formation of H2O2 over a gold nanocatalyst, by studying the energetics of 20 possible elementary...... reactions involved in the oxidation of H-2 by O-2. The unwanted side reaction to H2O is also considered. Next we evaluate the degree of catalyst control and address the factors controlling the activity and the selectivity. By combining well-known energy scaling relations with microkinetic modeling, we show...

  8. Economy of Catalyst Synthesis-Convenient Access to Libraries of Di- and Tetranaphtho Azepinium Compounds.

    Science.gov (United States)

    Tharamak, Sorachat; Knittl-Frank, Christian; Manaprasertsak, Auraya; Pengsook, Anchulee; Suchy, Lydia; Schuller, Philipp; Happl, Barbara; Roller, Alexander; Widhalm, Michael

    2018-03-24

    Efficient optimization procedures in chiral catalysis are usually linked to a straightforward strategy to access groups of structurally similar catalysts required for fine-tuning. The ease of building up such ligand libraries can be increased when the structure-modifying step (introduction of a substituent) is done at a later stage of the synthesis. This is demonstrated for the extended family of di- and tetranaphtho azepinium compounds, widely used as chiral phase transfer catalysts (PTC). Using 2,6-diiodo-4,5-dihydro-3 H -dinaphtho[2,1-c:1',2'-e]azepine and 4,8-diiodo-6,7-dihydro-5 H -dibenzo[c,e]azepine, respectively, as key intermediates, 18 spiro -azepinium compounds were synthesized in a total yield of 25-42% over 6-7 steps from 1,1'-binaphthyl-2,2'-dicarboxylic acid or diphenic acid, respectively. The replacement of iodo groups with aryl substituents was performed as the last or the penultimate step of the synthesis.

  9. Dimethyl carbonate synthesis via transesterification of propylene carbonate with methanol by ceria-zinc catalysts: Role of catalyst support and reaction parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Praveen; Srivastava, Vimal Chandra; Mishra, Indra Mani [Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand (India)

    2015-09-15

    Ceria and zinc oxide catalyst were impregnated onto various oxide supports, namely Al{sub 2}O{sub 3}, TiO{sub 2} and SiO{sub 2}, individually by deposition-coprecipitation method. The synthesized catalysts (CZA, CZS and CZT having supports Al{sub 2}O{sub 3}, TiO{sub 2} and SiO{sub 2}, respectively) were characterized by X-ray diffraction (XRD), NH{sub 3}- and CO{sub 2}-temperature programmed desorption (TPD) and N2 adsorption. These catalysts were used for synthesis of dimethyl carbonate (DMC) from methanol and propylene carbonate in a batch reactor. CZS was found to have larger average grain size as compared to CZA and CZT. Composite oxides (catalysts) were found to contain individual phases of ZnO, CeO{sub 2} and some spinel forms of Zn, Ce along with their supports. CZS having highest basicity and surface area showed better catalytic activity as compared to CZA and CZT. Effect of reaction temperature and methanol/PC molar ratio on DMC yield was studied and a reaction mechanism has been discussed. Maximum DMC yield of 77% was observed with CZS catalyst at 170 .deg. C with methanol/PC molar ratio of 10.

  10. Novel synthesis of highly durable and active Pt catalyst encapsulated in nitrogen containing carbon for polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Lee, Hyunjoon; Sung, Yung-Eun; Choi, Insoo; Lim, Taeho; Kwon, Oh Joong

    2017-09-01

    Novel synthesis of a Pt catalyst encapsulated in a N-containing carbon layer for use in a polymer electrolyte membrane fuel cell is described in this study. A Pt-aniline complex, formed by mixing Pt precursor and aniline monomer, was used as the source of Pt, C, and N. Heat treatment of the Pt-aniline complex with carbon black yielded 5 nm Pt nanoparticles encapsulated by a N-containing carbon layer originating from aniline carbonization. The synthesized Pt catalyst exhibited higher mass specific activity to oxygen reduction reaction than that shown by conventional Pt/C catalyst because pyridinic N with graphitic carbon in the carbon layer provided active sites for oxygen reduction reaction in addition to those provided by Pt. In single cell testing, initial performance of the synthesized catalyst was limited because the thick catalyst layer increased resistance related to mass transfer. However, it was observed that the carbon layer successfully prevented Pt nanoparticles from growing via agglomeration and Ostwald ripening under fuel cell operation, thereby improving durability. Furthermore, a mass specific performance of the synthesized catalyst higher than that of a conventional Pt/C catalyst was achieved by modifying the synthesized catalyst's layer thickness.

  11. Cationic Zn-Porphyrin Polymer Coated onto CNTs as a Cooperative Catalyst for the Synthesis of Cyclic Carbonates.

    Science.gov (United States)

    Jayakumar, Sanjeevi; Li, He; Chen, Jian; Yang, Qihua

    2018-01-24

    The development of solid catalysts containing multiple active sites that work cooperatively is very attractive for biomimetic catalysis. Herein, we report the synthesis of bifunctional catalysts by supporting cationic porphyrin-based polymers on carbon nanotubes (CNTs) using the direct reaction of 5,10,15,20-tetrakis(4-pyridyl)porphyrin zinc(II), di(1H-imidazol-1-yl)methane, and 1,4-bis(bromomethyl)benzene in the presence of CNTs. The bifunctional catalysts could efficiently catalyze the cycloaddition reaction of epoxides and CO 2 under solvent-free conditions with porphyrin zinc(II) as the Lewis acid site and a bromine anion as a nucleophilic agent working in a cooperative way. Furthermore, a relative amount of porphyrin zinc(II) and quaternary ammonium bromide could be facilely adjusted for facilitating cooperative behavior. The bifunctional catalyst with a TOF up to 2602 h -1 is much more active than the corresponding homogeneous counterpart and is one of the most active heterogeneous catalysts ever reported under cocatalyst-free conditions. The high activity is mainly attributed to the enhanced cooperation effect of the bifunctional catalyst. With a wide substrate scope, the bifunctional catalyst could be stably recycled. This work demonstrates a new approach for the generation of a cooperative activation effect for solid catalysts.

  12. Dispersed metal cluster catalysts by design. Synthesis, characterization, structure, and performance

    Energy Technology Data Exchange (ETDEWEB)

    Arslan, Ilke [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dixon, David A. [Univ. of Alabama, Tuscaloosa, AL (United States); Gates, Bruce C. [Univ. of California, Davis, CA (United States); Katz, Alexander [Univ. of California, Berkeley, CA (United States)

    2015-09-30

    To understand the class of metal cluster catalysts better and to lay a foundation for the prediction of properties leading to improved catalysts, we have synthesized metal catalysts with well-defined structures and varied the cluster structures and compositions systematically—including the ligands bonded to the metals. These ligands include supports and bulky organics that are being tuned to control both the electron transfer to or from the metal and the accessibility of reactants to influence catalytic properties. We have developed novel syntheses to prepare these well-defined catalysts with atomic-scale control the environment by choice and placement of ligands and applied state-of-the art spectroscopic, microscopic, and computational methods to determine their structures, reactivities, and catalytic properties. The ligands range from nearly flat MgO surfaces to enveloping zeolites to bulky calixarenes to provide controlled coverages of the metal clusters, while also enforcing unprecedented degrees of coordinative unsaturation at the metal site—thereby facilitating bonding and catalysis events at exposed metal atoms. With this wide range of ligand properties and our arsenal of characterization tools, we worked to achieve a deep, fundamental understanding of how to synthesize robust supported and ligand-modified metal clusters with controlled catalytic properties, thereby bridging the gap between active site structure and function in unsupported and supported metal catalysts. We used methods of organometallic and inorganic chemistry combined with surface chemistry for the precise synthesis of metal clusters and nanoparticles, characterizing them at various stages of preparation and under various conditions (including catalytic reaction conditions) and determining their structures and reactivities and how their catalytic properties depend on their compositions and structures. Key characterization methods included IR, NMR, and EXAFS spectroscopies to identify

  13. Biodiesel synthesis via transesterification of lipid Chlorophyta cultivated in walne rich carbon medium using KOH/Zeolite catalyst

    Science.gov (United States)

    Dianursanti, Hayati, Siti Zahrotul; Putri, Dwini Normayulisa

    2017-11-01

    Microalgae from the Chlorophyta division such as Nannochloropsis oculata and Chlorella vulgaris are highly potential to be developed as biodiesel feedstocks because they have a high oil content up to 58%. Biodiesel is produced by transesterification of triglycerides and alcohols with the aid of homogeneous catalysts such as KOH. However, the use of KOH catalysts produces soaps in the biodiesel synthesis. Heterogeneous catalysts are known to solve this problem. One of them is natural zeolite. Zeolite can be used as a catalyst and as a support catalyst. Loading KOH on the zeolite surface is expected to increase alkalinity in KOH/Zeolite catalysts so as to increase the activity of KOH/Zeolite catalyst in transesterification of triglyceride with methanol. In this experimental lipid of microalgae will be used for produced biodiesel via transesterification reaction with methanol and KOH/Zeolite as a catalyst heterogeneous at 60 °C for 3h and utilized catalyst modificated KOH/Zeolite with variation 0.5 M, 1 M and 1.5 M KOH. The modified zeolite was then analyzed by XRF, XRD and BET. The result showed that the yield of biodiesel from lipid N.oculata was 81,09% by 0.5KOH/Zeolite catalyst, 86,53% by 1KOH/Zeolite catalyst, 1,5KOH/Zeolite and 88,13% by 1.5KOH/Zeolit, while the biodiesel produced from lipid C.vulgaris was 59.29% by 0.5KOH/Zeolite, 82.27% by 1KOH/Zeolite and 83.72% by 1.5KOH/Zeolite.

  14. Effect of Lanthanum as a Promoter on Fe-Co/SiO2 Catalyst for Fischer-Tropsch Synthesis

    Directory of Open Access Journals (Sweden)

    Ali Abbasi

    2014-03-01

    Full Text Available Iron-Cobalt catalyst is well known from both operational and economical aspects for Fischer-Tropsch synthesis. Effort to increase the efficiency of this kind of catalyst is an important research topic. In this work, the effect of lanthanum on characteristic behavior, conversion and selectivity of a Fe-Co/SiO2 Fischer-Tropsch catalyst was studied. The Fe-Co-La/SiO2 Catalysts were prepared using an incipient wetness impregnation method. These catalysts were then characterized by XRF-EDAX, BET and TPR techniques, and their performance were evaluated in a lab-scale reactor at 250ºC, H2/CO = 1.8 of molar ratio, 16 barg pressure and GHSV=600 h-1. TPR analysis showed that the addition of La lowered the reduction temperature of Fe-Co catalyst, and due to a lower temperature, the sintering of the catalyst can be mitigated. Furthermore, from the micro reactor tests (about 4 days, it was found that lanthanum promoted catalyst had higher selectivity toward hydrocarbons, and lower selectivity toward CO2.Received: 8th July 2013; Revised: 18th November 2013; Accepted: 1st December 2013[How to Cite: Abbasi, A., Ghasemi, M., Sadighi, S. (2014. Effect of Lanthanum as a Promoter on Fe-Co/SiO2 Catalyst for Fischer-Tropsch Synthesis. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 23-27. (doi:10.9767/bcrec.9.1.5142.23-27][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.5142.23-27

  15. Upgrading of glycerol from biodiesel synthesis with dimethyl carbonate on reusable Sr–Al mixed oxide catalysts

    International Nuclear Information System (INIS)

    Algoufi, Y.T.; Akpan, U.G.; Kabir, G.; Asif, M.; Hameed, B.H.

    2017-01-01

    Highlights: • Catalytic transesterification with dimethyl carbonate (DMC) converts glycerol into glycerol carbonate (GLC). • DMC and Sr_x–Al catalysts affect the reaction mechanisms that convert glycerol into GLC. • The morphology and textural structure of Sr_x–Al catalysts perpetuate catalytic activity. • The atomic ratio of Sr/Al has a unique effect on Sr–Al catalytic activity. • Sr_0_._5–Al catalyst exhibits limited leaching after five reaction cycles. - Abstract: The high demand for renewable energy has led to the upsurge of methanol-assisted biodiesel synthesis. Therefore, glycerol as a byproduct entered the waste stream given the oversupply of biodiesel to the market. The dimethyl carbonate (DMC)-assisted transesterification of glycerol on a catalyst has been a popular approach for converting glycerol into valuable glycerol carbonate (GLC). The synthesis of GLC from the DMC-assisted transesterification of glycerol on mixed oxide catalysts (Sr_x–Al) with different Sr/Al ratios was examined in this study. A glycerol conversion of 99.4% and a GLC yield of 100% were achieved in a catalyst with Sr/Al = 0.5 (Sr_0_._5–Al). Both values are higher than those in catalysts synthesized with Sr/Al = 0.25 and 0.75. The Sr_0_._5–Al catalyst withstood five transesterification reaction cycles without a serious deactivation induced by the leaching of active SrO. Therefore, the Sr_0_._5–Al catalyst is suitable for consecutive uses in the DMC-assisted transesterification of glycerol with DMC into GLC.

  16. Selective synthesis of vitamin K3 over mesoporous NbSBA-15 catalysts synthesized by an efficient hydrothermal method.

    Science.gov (United States)

    Selvaraj, M; Park, D-W; Kim, I; Kawi, S; Ha, C S

    2012-08-28

    Well hexagonally ordered NbSBA-15 catalysts synthesized by an efficient hydrothermal method were used, for the first time, for the selective synthesis of vitamin K(3) by liquid-phase oxidation of 2-methyl-1-naphthol (2MN1-OH) under various reaction conditions. The recyclable NbSBA-15 catalysts were also reused to find their catalytic activities. To investigate the leaching of non-framework niobium species on the surface of silica networks, the results of original and recyclable NbSBA-15 catalysts were correlated and compared. To find an optimum condition for the selective synthesis of vitamin K(3), the washed NbSBA-15(2.2pH) was extensively used in this reaction with various reaction parameters such as temperature, time and ratios of reactant (2M1N-OH to H(2)O(2)), and the obtained results were also demonstrated. Additionally, the liquid-phase oxidation of 2M1N-OH was carried out with different solvents to find the best solvent with a good catalytic activity. Based on the all catalytic studies, the vitamin K(3) selectivity (97.3%) is higher in NbSBA-15(2.2pH) than that of other NbSBA-15 catalysts, and the NbSBA-15(2.2pH) is found to be a highly active and eco-friendly heterogeneous catalyst for the selective synthesis of vitamin K(3).

  17. Adsorption and Deactivation Characteristics of Cu/ZnO-Based Catalysts for Methanol Synthesis from Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Natesakhawat, Sittichai; Ohodnicki, Paul R; Howard, Bret H; Lekse, Jonathan W; Baltrus, John P; Matranga, Christopher

    2013-07-09

    The adsorption and deactivation characteristics of coprecipitated Cu/ZnO-based catalysts were examined and correlated to their performance in methanol synthesis from CO₂ hydrogenation. The addition of Ga₂O₃ and Y₂O₃ promoters is shown to increase the Cu surface area and CO₂/H₂ adsorption capacities of the catalysts and enhance methanol synthesis activity. Infrared studies showed that CO₂ adsorbs spontaneously on these catalysts at room temperature as both monoand bi-dentate carbonate species. These weakly bound species desorb completely from the catalyst surface by 200 °C while other carbonate species persist up to 500 °C. Characterization using N₂O decomposition, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDX) analysis clearly indicated that Cu sintering is the main cause of catalyst deactivation. Ga and Y promotion improves the catalyst stability by suppressing the agglomeration of Cu and ZnO particles under pretreatment and reaction conditions.

  18. Synthesis and Evaluation of Nanostructured Gold-Iron Oxide Catalysts for the Oxidative Dehydrogenation of Cyclohexane

    Science.gov (United States)

    Wu, Peng

    Shape-controlled iron oxide and gold-iron oxide catalysts with a cubic inverse spinel structure were studied in this thesis for the oxidative dehydrogenation of cyclohexane. The structure of iron oxide and gold-iron oxide catalysts has no major impact on their oxidative dehydrogenation activity. However, the product selectivity is influenced. Both cyclohexene and benzene are formed on bare iron oxide nanoshapes, while benzene is the only dehydrogenation product in the presence of gold. The selectivity of benzene over CO2 depends strongly on the stability of the iron oxide support and the gold-support interaction. The highest benzene yield has been observed on gold-iron oxide octahedra. {111}-bound nanooctahedra are highly stable in reaction conditions at 300 °C, while {100}-bound nanocubes start to sinter above 250 °C. The highest benzene yield has been observed on gold-iron oxide nanooctahedra, which are likely to have gold atoms, and few-atom gold clusters strongly-bound on their surface. Cationic gold appears to be the active site for benzene formation. An all-organic method to prepare Au-FeOx nano-catalysts is needed due to the inconvenience of the half-organic, half-inorganic synthesis process discussed above. Several methods from the literature to prepare gold-iron oxide nanocomposites completely in organic solvents were reviewed and followed. FeOx Au synthesis procedures in literatures are initially designed for a Au content of over 70%. This approach was tried here to prepare composites with a much lower Au content (2-5 atom. %). Heat treatment is required to bond Au and FeOx NPs in the organic-phase syntheses. Au-FeOx-4 was obtained as a selective catalyst for the ODH of cyclohexane. A Audelta+ peak is observed in the UV-Vis spectrum of sample Au-FeOx-4. This different Au delta+ form may be cationic Au nano-clusters interacting with the FeOx support. It has been demonstrated that cationic gold is responsible for dehydrogenation behavior. Furthermore, the

  19. Ethanol synthesis and water gas shift over bifunctional sulfide catalysts. Final technical progress report, September 12, 1991--December 11, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Klier, K.; Herman, R.G.; Deemer, M.; Richards-Babb, M.; Carr, T.

    1995-07-01

    The objective of this research was to investigate sulfur-resistant catalysts for the conversion of synthesis gas having H{sub 2}/CO {le} 1 into C{sub 1}--C{sub 4} alcohols, especially ethanol, by a highly selective and efficient pathway, while also promoting the water gas shift reaction (WGSR). The catalysts chosen are bifunctional, base-hydrogenation, sulfur-tolerant transition metal sulfides with heavy alkali, e.g. Cs{sup +}, promoter dispersed on their surfaces. The modes of activation of H{sub 2} and CO on MoS{sub 2} and alkali-doped MoS{sub 2} were considered, and computational analyses of the thermodynamic stability of transition metal sulfides and of the electronic structure of these sulfide catalysts were carried out. In the preparation of the cesium-promoted MoS{sub 2} catalysts, a variety of preparation methods using CsOOCH were examined. In all cases, doping with CsOOCH led to a lost of surface area. The undoped molybdenum disulfide catalyst only produced hydrocarbons. Cs-doped MoS{sub 2} catalysts all produced linear alcohols, along with smaller amounts of hydrocarbons. With a 20 wt% CsOOCH/MoS{sub 2} catalyst, temperature, pressure, and flow rate dependences of the synthesis reactions were investigated in the presence and absence of H{sub 2}S in the H{sub 2}/CO = 1/1 synthesis gas during short term testing experiments. It was shown that with a carefully prepared 10 wt% CsOOCH/MoS{sub 2} catalyst, reproducible and high alcohol synthesis activity could be obtained. For example, at 295 C with H{sub 2}/CO = 1 synthesis gas at 8.3 MPa and with GHSV = 7,760 l/kg cat/hr, the total alcohol space time yield was ca 300 g/kg cat/hr (accompanied with a hydrocarbon space time yield of ca 60 g/kg cat/hr). Over a testing period of ca 130 hr, no net deactivation of the catalyst was observed. 90 refs., 82 figs., 14 tabs.

  20. Benign by design: catalyst-free in-water, on-water green chemical methodologies in organic synthesis

    Science.gov (United States)

    The development of organic synthesis under sustainable conditions is a primary goal of practicing green chemists who want to prevent pollution and design safer pathways. Although, it is challenging to avoid the use of catalysts, or solvents in all the organic reactions but progre...

  1. A Simple Synthesis of an N-Doped Carbon ORR Catalyst: Hierarchical Micro/Meso/Macro Porosity and Graphitic Shells

    NARCIS (Netherlands)

    Eisenberg, D.; Stroek, W.; Geels, N.J.; Sandu, C.S.; Heller, A.; Yan, N.; Rothenberg, G.

    2016-01-01

    Replacing platinum as an oxygen reduction catalyst is an important scientific and technological challenge. Herein we report a simple synthesis of a complex carbon with very good oxygen reduction reaction (ORR) activity at pH 13. Pyrolysis of magnesium nitrilotriacetate yields a carbon with

  2. I2/K2CO3: An efficient catalyst for the synthesis of 5-aryl-2,6-dicyano ...

    Indian Academy of Sciences (India)

    Abstract. Molecular iodine in the presence of potassium carbonate has been found to be an efficient and eco- friendly catalyst for the synthesis of polysubstituted dicyanoanilines from aldehydes, acetone and malononitrile under solvent-free thermal condition. The experimental procedure is simple, includes shorter reaction ...

  3. Nano-particulate Aluminium Nitride/Al: An Efficient and Versatile Heterogeneous Catalyst for the Synthesis of Biginelli Scaffolds

    Science.gov (United States)

    Tekale, S. U.; Tekale, A. B.; Kanhe, N. S.; Bhoraskar, S. V.; Pawar, R. P.

    2011-12-01

    Nano-particulate aluminium nitride/Al (7:1) is reported as a new heterogeneous solid acid catalyst for the synthesis of 3, 4-dihydroxypyrimidi-2-(1H)-ones and their sulphur analogues using the Biginelli reaction. This method involves short reaction time, easy separation, high yields and purity of products.

  4. Quantification of zinc atoms in a surface alloy on copper in an industrial-type methanol synthesis catalyst

    DEFF Research Database (Denmark)

    Kuld, Sebastian; Moses, Poul Georg; Sehested, Jens

    2014-01-01

    Methanol has recently attracted renewed interest because of its potential importance as a solar fuel. Methanol is also an important bulk chemical that is most efficiently formed over the industrial Cu/ZnO/Al2O3 catalyst. The identity of the active site and, in particular, the role of ZnO as a pro......Methanol has recently attracted renewed interest because of its potential importance as a solar fuel. Methanol is also an important bulk chemical that is most efficiently formed over the industrial Cu/ZnO/Al2O3 catalyst. The identity of the active site and, in particular, the role of Zn......O as a promoter for this type of catalyst is still under intense debate. Structural changes that are strongly dependent on the pretreatment method have now been observed for an industrial-type methanol synthesis catalyst. A combination of chemisorption, reaction, and spectroscopic techniques provides a consistent...

  5. SYNTHESIS OF BIODIESEL ON A HYBRID CATALYTIC-PLASMA REACTOR OVER K2O/CaO-ZnO CATALYST

    Directory of Open Access Journals (Sweden)

    Luqman Buchori

    2017-10-01

    Full Text Available This paper aimed to study the synergistic effects of dielectric barrier discharge plasma and 5 % K2O/CaO-ZnO catalyst on biodiesel synthesis. The catalyst was prepared using co-precipitation followed by impregnation method. The catalyst was characterized by XRD, while the catalyst basicity was tested by titration method. The effects of voltage, weight hourly space velocity (WHSV, and catalyst pellet diameter on the yield of fatty acid methyl ester (FAME and biodiesel were studied. The transesterification process within and without plasma environment was investigated to find synergistic effect between the role of high energetic electrons from the plasma through the catalytic reaction zone and the role of basicity in the catalyst. From the results, an applied voltage of 5 kV, a WHSV of 1.186 min-1, and a catalyst diameter of 5 mm gave the better FAME yield of 77.19 %. The reaction time required was only 1.25 minutes at a discharge power of 530 W. This result proved that the plasma environment has a significant effect on performance of the hybrid catalytic-plasma reactor for biodiesel production.

  6. Tailoring Cu Nanoparticle Catalyst for Methanol Synthesis Using the Spinning Disk Reactor

    Directory of Open Access Journals (Sweden)

    Christian Ahoba-Sam

    2018-01-01

    Full Text Available Cu nanoparticles are known to be very active for methanol (MeOH synthesis at relatively low temperatures, such that smaller particle sizes yield better MeOH productivity. We aimed to control Cu nanoparticle (NP size and size distribution for catalysing MeOH synthesis, by using the spinning disk reactor. The spinning disk reactor (SDR, which operates based on shear effect and plug flow in thin films, can be used to rapidly micro-mix reactants in order to control nucleation and particle growth for uniform particle size distribution. This could be achieved by varying both physical and chemical operation conditions in a precipitation reaction on the SDR. We have used the SDR for a Cu borohydride reduction to vary Cu NP size from 3 nm to about 55 nm. XRD and TEM characterization confirmed the presence of Cu2O and Cu crystallites when the samples were dried. This technique is readily scalable for Cu NP production by processing continuously over a longer duration than the small-scale tests. However, separation of the nanoparticles from solution posed a challenge as the suspension hardly settled. The Cu NPs produced were tested to be active catalyst for MeOH synthesis at low temperature and MeOH productivity increased with decreasing particle size.

  7. Histidine as a catalyst in organic synthesis: A facile in situ synthesis ...

    Indian Academy of Sciences (India)

    Unknown

    They are also used in the synthesis of many nitrogen-containing biologically ... addition to hydroxylamine, results in formation of an imine, azoxy compound 15, ... GC-MS, m/z: 211 (M+), 194 (base peak); 13C NMR (DMSO-d6) δ : 31⋅14 ...

  8. {alpha}-Al{sub 2}O{sub 3} catalyst supports for synthesis gas production: influence of different alumina bonding agents on support and catalyst properties

    Energy Technology Data Exchange (ETDEWEB)

    Marturano, M. [Centro de Investigacion y Desarrollo en Procesos Cataliticos, La Plata (Argentina); Aglietti, E.F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC), Gonnet (Argentina); Ferretti, O. [Centro de Investigacion y Desarrollo en Procesos Cataliticos, La Plata (Argentina)]|[Univ. Nacional de La Plata, Dept. de Ingenieria Quimica de la Facultad de Ingenieria, La Plata (Argentina)

    1997-02-01

    Aluminas are widely used as catalytic supports in chemical reactions. Reforming reactions to obtain synthesis gas requires good mechanical strength and low sintering behaviour. In this work, the influence of bentonite, aluminium phosphate and alumina gel as binder agents of a calcined {alpha}-Al{sub 2}O{sub 3} are analyzed with respect to support and catalytic properties. The {alpha}-Al{sub 2}O{sub 3} supports, calcined at 1300 C, are then impregnated with solutions of Ni and Al inorganic salts to obtain the catalysts and are finally tested in the reforming reaction of methane to synthesis gas at 500-900 C. Supports and catalysts are characterized by XRD, SEM, N{sub 2} adsorption, mechanical strength test and other techniques. Mechanical strength depends on the type and quantity of binder material used during support preparation. The influence of the support on the performance of the resulting catalyst is evidenced by means of catalytic tests. (orig.) 8 refs.

  9. Synthesis and Immobilization of Pt Nanoparticles on Amino-Functionalized Halloysite Nanotubes toward Highly Active Catalysts

    Directory of Open Access Journals (Sweden)

    Tingting Yang

    2015-02-01

    Full Text Available A simple and effective method for the preparation of platinum nanoparticles (Pt NPs grown on amino-func‐ tionalized halloysite nanotubes (HNTs was developed. The nanostructures were synthesized through the func‐ tionalization of the HNTs, followed by an in situ approach to generate Pt NPs with diameter of approximately 1.5 nm within the entire HNTs. The synthesis process, composition and morphology of the nanostructures were characterized. The results suggest PtNPs/NH2-HNTs nanostructures with ultrafine PtNPs were successfully synthesized by green chemically-reducing H2PtCl6 without the use of surfactant. The nanostructures exhibit promising catalytic properties for reducing potassium hexacyanoferrate(III to potassium hexacyanoferrate(II. The presented experiment for novel PtNPs/NH2-HNTs nanostructures is quite simple and environmentally benign, permitting it as a potential application in the future field of catalysts.

  10. Catalyst-controlled oligomerization for the collective synthesis of polypyrroloindoline natural products.

    Science.gov (United States)

    Jamison, Christopher R; Badillo, Joseph J; Lipshultz, Jeffrey M; Comito, Robert J; MacMillan, David W C

    2017-12-01

    In nature, many organisms generate large families of natural product metabolites that have related molecular structures as a means to increase functional diversity and gain an evolutionary advantage against competing systems within the same environment. One pathway commonly employed by living systems to generate these large classes of structurally related families is oligomerization, wherein a series of enzymatically catalysed reactions is employed to generate secondary metabolites by iteratively appending monomers to a growing serial oligomer chain. The polypyrroloindolines are an interesting class of oligomeric natural products that consist of multiple cyclotryptamine subunits. Herein we describe an iterative application of asymmetric copper catalysis towards the synthesis of six distinct oligomeric polypyrroloindoline natural products: hodgkinsine, hodgkinsine B, idiospermuline, quadrigemine H and isopsychotridine B and C. Given the customizable nature of the small-molecule catalysts employed, we demonstrate that this strategy is further amenable to the construction of quadrigemine H-type alkaloids not isolated previously from natural sources.

  11. Immobilised carbon nanotubes as carrier for Co-Fischer-Tropsch synthesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Thiessen, J.; Rose, A.; Kiendl, I.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering; Curulla-Ferre, D. [Total S.A., Gas and Power, Paris La Defense (France)

    2011-07-01

    A possibility to immobilise carbon nanotubes (CNT) to make them applicable in a technical scale fixed bed reactor is studied. The approach to fabricate millimetre scale composites containing CNT presented in this work is to confine the nano-carbon in macro porous ceramic particles. Thus CNT were grown on the inner surface of silica and alumina pellets and spheres, respectively. Cobalt nano particles were successfully deposited on the carbon surface inside the two types of ceramic carriers and the systems were tested in Fischer - Tropsch synthesis (FTS). The cobalt mass related activity of these novel catalysts is similar to a conventional system. The selectivities of the Co/CNT/ceramic composites were compared with non supported CNT and carbon nanofibres (CNF). (orig.)

  12. Tailoring the synthesis of supported Pd catalysts towards desired structure and size of metal particles.

    Science.gov (United States)

    Suresh, Gatla; Radnik, Jörg; Kalevaru, Venkata Narayana; Pohl, Marga-Martina; Schneider, Matthias; Lücke, Bernhard; Martin, Andreas; Madaan, Neetika; Brückner, Angelika

    2010-05-14

    In a systematic study, the influence of different preparation parameters on phase composition and size of metal crystallites and particles in Pd-Cu/TiO(2) and Pd-Sb/TiO(2) catalyst materials has been explored. Temperature and atmosphere of thermal pretreatment (pure He or 10% H(2)/He), nature of metal precursors (chlorides, nitrates or acetates) as well as of ammonium additives (ammonium sulfate, nitrate, carbonate) and urea were varied with the aim of tailoring the synthesis procedure for the preferential formation of metal particles with similar size and structure as observed recently in active catalysts after long-term equilibration under catalytic reaction conditions in acetoxylation of toluene to benzylacetate. Among the metal precursors and additives, the chloride metal precursors and (NH(4))(2)SO(4) were most suitable. Upon thermal pretreatment of Pd-Sb or Pd-Cu precursors, chloroamine complexes of Pd and Cu are formed, which decompose above 220 degrees C to metallic phases independent of the atmosphere. In He, metallic Pd particles were formed with both the co-components. In H(2)/He flow, Pd-Cu precursors were converted to core-shell particles with a Cu shell and a Pd core, while Sb(1)Pd(1) and Sb(7)Pd(20) alloy phases were formed in the presence of Sb. Metal crystallites of about 40 nm agglomerate to particles of up to 150 nm in He and to even larger size in H(2)/He.

  13. Preparation of mesoporous MnO2/C catalyst for n-hexyl acetate synthesis

    International Nuclear Information System (INIS)

    Yang Zeheng; Pan Yanmei; Mei Zhousheng; Zhang Weixin

    2012-01-01

    A mesoporous MnO 2 /C composite was prepared by impregnating self-made porous carbon spheres with manganese nitrate aqueous solution and subsequently reacting with KMnO 4 aqueous solution. It was characterized with X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), the Brunauer-Emmett-Teller (BET) surface area and the Barrett-Joyner-Halenda (BJH) pore size distribution. The as-prepared mesoporous MnO 2 /C composite was used as catalyst for the synthesis of n-hexyl acetate, and the effects of MnO 2 loading and esterification reaction parameters on the esterification rate were investigated. The results prove that MnO 2 loading has a significant effect on the catalytic activity and that the mesoporous MnO 2 /C composite exhibits high catalytic activity with an esterification rate of 96.42% under the conditions below: MnO 2 loading (73.09 wt%), catalyst dosage (0.1% in total weight), acetic acid/n-hexanol molar ratio (2:1), reaction temperature (130 °C) and reaction time (5 h).

  14. Impact of potassium promoter on Cu–Fe based mixed alcohols synthesis catalyst

    International Nuclear Information System (INIS)

    Ding, Mingyue; Tu, Junling; Qiu, Minghuang; Wang, Tiejun; Ma, Longlong; Li, Yuping

    2015-01-01

    Highlights: • Adding K facilitated the immigration of bulky iron species to surface layers. • Adding potassium strengthened the interaction of Fe–K on the surface layers. • Increasing K content facilitated the formation of C 2 + OH. • A maximum in catalytic activity is obtained at 0.5 wt.% of potassium loading. - Abstract: Impacts of K promoter on microstructures of a precipitated Cu–Fe based catalyst were studied by N 2 -physisorption (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD) and hydrogen temperature-programmed desorption/reduction (H 2 -TPD/TPR). Mixed alcohols synthesis (MAS) was carried out in a fixed-bed reactor. The results indicated that incorporation of K in the Cu–Fe based catalyst decreased the surface area of the particles, whereas promoted the immigration of bulky iron species to surface layers and strengthened the interaction of surface Fe–Cu. The increase of K concentration weakened the H 2 chemisorption and restrained the reduction of both the Cu and Fe species. The catalytic activity and mixed alcohols selectivity increased accompanied with a gradually increasing K concentration, and reached the highest values as the amount of K increased to 0.5 wt.%. Subsequently, the MAS activity and selectivity C 2 + OH presented a decreasing trend. In addition, the increase of K concentration facilitated the formation of heavy hydrocarbons

  15. Influence of Reduction Promoters on Stability of Cobalt/g-Alumina Fischer-Tropsch Synthesis Catalysts

    Directory of Open Access Journals (Sweden)

    Gary Jacobs

    2014-03-01

    Full Text Available This focused review article underscores how metal reduction promoters can impact deactivation phenomena associated with cobalt Fischer-Tropsch synthesis catalysts. Promoters can exacerbate sintering if the additional cobalt metal clusters, formed as a result of the promoting effect, are in close proximity at the nanoscale to other cobalt particles on the surface. Recent efforts have shown that when promoters are used to facilitate the reduction of small crystallites with the aim of increasing surface Co0 site densities (e.g., in research catalysts, ultra-small crystallites (e.g., <2–4.4 nm formed are more susceptible to oxidation at high conversion relative to larger ones. The choice of promoter is important, as certain metals (e.g., Au that promote cobalt oxide reduction can separate from cobalt during oxidation-reduction (regeneration cycles. Finally, some elements have been identified to promote reduction but either poison the surface of Co0 (e.g., Cu, or produce excessive light gas selectivity (e.g., Cu and Pd, or Au at high loading. Computational studies indicate that certain promoters may inhibit polymeric C formation by hindering C-C coupling.

  16. HKUST-1 as a Heterogeneous Catalyst for the Synthesis of Vanillin.

    Science.gov (United States)

    Yépez, Rebeca; Illescas, Juan F; Gijón, Paulina; Sánchez-Sánchez, Manuel; González-Zamora, Eduardo; Santillan, Rosa; Álvarez, J Raziel; Ibarra, Ilich A; Aguilar-Pliego, Julia

    2016-07-23

    Vanillin (4-hydoxy-3-methoxybenzaldehyde) is the main component of the extract of vanilla bean. The natural vanilla scent is a mixture of approximately 200 different odorant compounds in addition to vanillin. The natural extraction of vanillin (from the orchid Vanilla planifolia, Vanilla tahitiensis and Vanilla pompon) represents only 1% of the worldwide production and since this process is expensive and very long, the rest of the production of vanillin is synthesized. Many biotechnological approaches can be used for the synthesis of vanillin from lignin, phenolic stilbenes, isoeugenol, eugenol, guaicol, etc., with the disadvantage of harming the environment since these processes use strong oxidizing agents and toxic solvents. Thus, eco-friendly alternatives on the production of vanillin are very desirable and thus, under current investigation. Porous coordination polymers (PCPs) are a new class of highly crystalline materials that recently have been used for catalysis. HKUST-1 (Cu3(BTC)2(H2O)3, BTC = 1,3,5-benzene-tricarboxylate) is a very well known PCP which has been extensively studied as a heterogeneous catalyst. Here, we report a synthetic strategy for the production of vanillin by the oxidation of trans-ferulic acid using HKUST-1 as a catalyst.

  17. Influence of platinum group metal-free catalyst synthesis on microbial fuel cell performance

    Science.gov (United States)

    Santoro, Carlo; Rojas-Carbonell, Santiago; Awais, Roxanne; Gokhale, Rohan; Kodali, Mounika; Serov, Alexey; Artyushkova, Kateryna; Atanassov, Plamen

    2018-01-01

    Platinum group metal-free (PGM-free) ORR catalysts from the Fe-N-C family were synthesized using sacrificial support method (SSM) technique. Six experimental steps were used during the synthesis: 1) mixing the precursor, the metal salt, and the silica template; 2) first pyrolysis in hydrogen rich atmosphere; 3) ball milling; 4) etching the silica template using harsh acids environment; 5) the second pyrolysis in ammonia rich atmosphere; 6) final ball milling. Three independent batches were fabricated following the same procedure. The effect of each synthetic parameters on the surface chemistry and the electrocatalytic performance in neutral media was studied. Rotating ring disk electrode (RRDE) experiment showed an increase in half wave potential and limiting current after the pyrolysis steps. The additional improvement was observed after etching and performing the second pyrolysis. A similar trend was seen in microbial fuel cells (MFCs), in which the power output increased from 167 ± 2 μW cm-2 to 214 ± 5 μW cm-2. X-ray Photoelectron Spectroscopy (XPS) was used to evaluate surface chemistry of catalysts obtained after each synthetic step. The changes in chemical composition were directly correlated with the improvements in performance. We report outstanding reproducibility in both composition and performance among the three different batches.

  18. Synthesis of Alkylpoly glucoside from Dextrose-Decanol in the Presence of Silicotungstic Acid Sol-Gel Catalyst

    International Nuclear Information System (INIS)

    Izazi Azzahidah Amin; Mohd Ambar Yarmo; Nik Idris Nik Yusoff

    2013-01-01

    The purpose of this study is to synthesis alkylpoly glucoside via condensation of decanol with dextrose in the presence of heterogenous catalyst. In this study, silicotungstic acid sol-gel (STSG) prepared using sol-gel was used as solid acid catalyst. The catalyst was characterized using BET surface area measurement, X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) surface analysis. The final product was easy to be separated from catalyst without the need of a further neutralization. Silicotungstic acid sol-gel has been found efficient to be solid catalyst for synthesis alkylpoly glucosides. Condensation reaction was carried out 8 hours at 110-120 degree Celsius under vacuum condition at 10 mmHg. The determination of decyl glucoside has been achieved by LC/ ESI-MS/ MS (ToF) giving a mass peak at m/z = 343.2 correspond to the m/z of [M+Na] + . Alkylpoly glucoside produced was analysed by FTIR, 1 H and 13 C NMR spectrometric technique. (author)

  19. 3D-modelling of bifunctional core-shell catalysts for the production of fuels from biomass-based synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Wenjin; Lee, Seung Cheol; Li, Hui; Pfeifer, Peter; Dittmeyer, Roland [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (Germany). Inst. for Micro Process Engineering (IMVT)

    2013-09-01

    Until now, the main route for the production of DME from synthesis gas in industry is methanol synthesis on a metallic catalyst and subsequent dehydration of methanol on an acid catalyst (two-step process). A single-step process using bifunctional catalysts to perform the two steps simultaneously would be preferred e.g. due to thermodynamic considerations; but this is impeded by the higher volumetric heat release which may cause deactivation of the methanol synthesis catalyst function. Thus we propose to conduct the reaction in a microchannel reactor. However, in order to increase the productivity of the microchannel reactor and to lower the investment costs, we aim at a high selectivity and activity of the catalyst. The continuously removal of methanol by dehydration on an acidic ZSM-5 catalyst as shell improves the thermodynamic conditions of methanol synthesis in the CuO/ZnO/Al{sub 2}O{sub 3} core; thus, the synthesis gas conversion can be higher than that determined by the thermodynamics of pure methanol synthesis. The molecular sieving in the zeolite layer can further lead to higher selectivity of DME at milder reaction conditions. However, mass transport limitation of the synthesis gas to the catalyst core should not hinder the reaction, and therefore a more detailed investigation is required. In order to computer-aided optimize the catalyst structure and the operating conditions for core-shell catalysts, a simulation model should be developed to study the coupled reaction and transport processes in core-shell catalysts. In this simulation model the complicated interaction of diffusion and reaction in the zeolite layer (shell) must be detailed by a network model to describe its structure and the mechanisms effectively. In addition, suitable diffusion and kinetic models are required to describe the mass transport and reactions in the layer. Suitable networks, diffusion and kinetic models are discussed for 3D simulations in this contribution. (orig.)

  20. Synthesis and Characterization of Cobalt Containing Nanoparticles on Alumina A Potential Catalyst for Gas to Liquid Fuels Production

    Science.gov (United States)

    Cowen, Jonathan; Hepp, Aloysius F.

    2016-01-01

    Fisher-Tröpsch synthesis (FTS) is a century-old gas-to-liquid (GTL) technology that commonly employs cobalt (Co, on an oxide support) or iron (supported or not) species catalysts. It has been well established that the activity of the Co catalyst depends directly upon the number of surface Co atoms. The addition of promoter (mainly noble) metals has been widely utilized to increase the fraction of Co that is available for surface catalysis. Direct synthesis of Co nanoparticles is a possible alternative approach; our preliminary synthesis and characterization efforts are described. Materials were characterized by various transmission microscopies and energy dispersive spectroscopy. Tri-n-octylphosphine oxide (TOPO) and dicobalt octacarbonyl were heated under argon to a temperature of 180 deg with constant stirring for 1 hr. Quenching the reaction in toluene produced Co-containing nanoparticles with a diameter of 5 to 10 nm. Alternatively, an alumina support (SBA-200 Al2O3) was added; the reaction was further stirred and the temperature was decreased to 140 deg to reduce the rate of further growth/ripening of the nucleated Co nanoparticles. A typical size of Co-containing NPs was also found to be in the range of 5 to 10 nm. This can be contrasted with a range of 50 to 200 nm for conventionally-produced Co-Al2O3 Fischer-Tröpsch catalysts. This method shows great potential for production of highly dispersed catalysts that are either supported or unsupported.

  1. The synthesis of carbon nanocomposites as fuel cell catalyst support and the characterization of fuel cell catalysts by spatially resolved scanning mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Li, Nan

    2007-07-01

    Ammonia decomposition over Ni/SiO{sub 2} and Ni/MgO was investigated by temperature-programmed desorption (TPD) and temperature-programmed surface reaction (TPSR) in order to produce CO{sub x} free hydrogen fuel for fuel cell application. A highly efficient route for the synthesis of carbon nanocomposites based on electrochemical deposition and iron catalyzed chemical vapor deposition (CVD) was developed in order to obtain a promising substrate for fuel cell catalysts. The duration of electrochemical deposition, temperature and time for the carbon nanotubes (CNTs) growth had been optimized to achieve higher surface area after the growth. Hierarchically structured CNTs composites had been synthesized and electrochemical studies provided evidence for the strong interaction among the substrate and grown CNTs, which are essential for the application in fuel cells. A straightforward strategy was developed to synthesize well dispersed gold nanoparticles with a diameter of 4 to 6 nm on the sidewall of multi-walled carbon nanotubes (MWNTs). A gas flow set-up was developed for the evaluation of fuel cell catalysts by performing scanning mass spectrometry with integrated constant-distance positioning. Methanol oxidation was identified as a suitable test reaction. The diameter of scanning probe was reduced in order to achieve higher spatial resolution. Spatially resolved scanning mass spectrometry was successfully applied to visualize the catalytic activity over Pt-based catalysts and monitor the local activity of a catalysts coated membrane (CCM). The gas-solid phase reaction results were proved to be accurate, reliable and independent of the sample topography. This analytical method opens the way for fast quality control of the catalyst coating with respect to even coating and absence of damages, and for a better understanding of the CCM degradation in polymer membrane electrolyte fuel cells (PEMFCs). (orig.)

  2. A Facile Synthesis of Hollow Palladium/Copper Alloy Nanocubes Supported on N-Doped Graphene for Ethanol Electrooxidation Catalyst

    OpenAIRE

    Zhengyu Bai; Rumeng Huang; Lu Niu; Qing Zhang; Lin Yang; Jiujun Zhang

    2015-01-01

    In this paper, a catalyst of hollow PdCu alloy nanocubes supported on nitrogen-doped graphene support (H-PdCu/ppy-NG) is successfully synthesized using a simple one-pot template-free method. Two other catalyst materials such as solid PdCu alloy particles supported on this same nitrogen-doped graphene support (PdCu/ppy-NG) and hollow PdCu alloy nanocubes supported on the reduced graphene oxide support (H-PdCu/RGO) are also prepared using the similar synthesis conditions for comparison. It is f...

  3. Synthesis of CaOZnO Nanoparticles Catalyst and Its Application in Transesterification of Refined Palm Oil

    Directory of Open Access Journals (Sweden)

    Cicik Herlina Yulianti

    2014-07-01

    Full Text Available The CaOZnO nanoparticle catalysts with Ca to Zn atomic ratios of 0.08 and 0.25 have been successfully synthesized by co-precipitation method. The catalyst was characterized by X-ray Diffraction (XRD analysis provided with Rietica and Maud software, Scanning Electron Microscopy (SEM and Fourier Transform Infrared spectroscopy (FT-IR, and its properties was compared with bare CaO and ZnO catalysts. The phase composition estimated by Rietica software revealed that the CaO catalyst consists of CaO and CaCO3 phases. The estimation of the particle size by Maud software, showed that the particle size of all catalysts increased by the following order: ZnO. © 2014 BCREC UNDIP. All rights reservedReceived: 1st January 2014; Revised: 10th March 2014; Accepted: 18th March 2014[How to Cite: Yulianti, C.H., Ediati, R., Hartanto, D., Purbaningtias, T.E., Chisaki, Y., Jalil, A.A., Hitam, C.K.N.L.C.K., Prasetyoko, D., (2014. Synthesis of CaOZnO Nanoparticles Catalyst and Its Application in Transesterification of Refined Palm Oil. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (2: 100-110. (doi:10.9767/bcrec.9.2.5998.100-110][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.2.5998.100-110

  4. Green Synthesis of Three-Dimensional Hybrid N-Doped ORR Electro-Catalysts Derived from Apricot Sap

    Directory of Open Access Journals (Sweden)

    Ramesh Karunagaran

    2018-01-01

    Full Text Available Rapid depletion of fossil fuel and increased energy demand has initiated a need for an alternative energy source to cater for the growing energy demand. Fuel cells are an enabling technology for the conversion of sustainable energy carriers (e.g., renewable hydrogen or bio-gas into electrical power and heat. However, the hazardous raw materials and complicated experimental procedures used to produce electro-catalysts for the oxygen reduction reaction (ORR in fuel cells has been a concern for the effective implementation of these catalysts. Therefore, environmentally friendly and low-cost oxygen reduction electro-catalysts synthesised from natural products are considered as an attractive alternative to currently used synthetic materials involving hazardous chemicals and waste. Herein, we describe a unique integrated oxygen reduction three-dimensional composite catalyst containing both nitrogen-doped carbon fibers (N-CF and carbon microspheres (N-CMS synthesised from apricot sap from an apricot tree. The synthesis was carried out via three-step process, including apricot sap resin preparation, hydrothermal treatment, and pyrolysis with a nitrogen precursor. The nitrogen-doped electro-catalysts synthesised were characterised by SEM, TEM, XRD, Raman, and BET techniques followed by electro-chemical testing for ORR catalysis activity. The obtained catalyst material shows high catalytic activity for ORR in the basic medium by facilitating the reaction via a four-electron transfer mechanism.

  5. Green Synthesis of Three-Dimensional Hybrid N-Doped ORR Electro-Catalysts Derived from Apricot Sap.

    Science.gov (United States)

    Karunagaran, Ramesh; Coghlan, Campbell; Shearer, Cameron; Tran, Diana; Gulati, Karan; Tung, Tran Thanh; Doonan, Christian; Losic, Dusan

    2018-01-28

    Rapid depletion of fossil fuel and increased energy demand has initiated a need for an alternative energy source to cater for the growing energy demand. Fuel cells are an enabling technology for the conversion of sustainable energy carriers (e.g., renewable hydrogen or bio-gas) into electrical power and heat. However, the hazardous raw materials and complicated experimental procedures used to produce electro-catalysts for the oxygen reduction reaction (ORR) in fuel cells has been a concern for the effective implementation of these catalysts. Therefore, environmentally friendly and low-cost oxygen reduction electro-catalysts synthesised from natural products are considered as an attractive alternative to currently used synthetic materials involving hazardous chemicals and waste. Herein, we describe a unique integrated oxygen reduction three-dimensional composite catalyst containing both nitrogen-doped carbon fibers (N-CF) and carbon microspheres (N-CMS) synthesised from apricot sap from an apricot tree. The synthesis was carried out via three-step process, including apricot sap resin preparation, hydrothermal treatment, and pyrolysis with a nitrogen precursor. The nitrogen-doped electro-catalysts synthesised were characterised by SEM, TEM, XRD, Raman, and BET techniques followed by electro-chemical testing for ORR catalysis activity. The obtained catalyst material shows high catalytic activity for ORR in the basic medium by facilitating the reaction via a four-electron transfer mechanism.

  6. Carbon and Mo transformations during the synthesis of mesoporous Mo2C/carbon catalysts by carbothermal hydrogen reduction

    Science.gov (United States)

    Wang, Haiyan; Liu, Shida; Liu, Bing; Montes, Vicente; Hill, Josephine M.; Smith, Kevin J.

    2018-02-01

    The synthesis of mesoporous Mo2C/carbon catalysts by carbothermal hydrogen reduction is reported. Petroleum coke (petcoke) was activated with KOH at 800 °C to obtain high surface area microporous activated petcoke (APC; 2000 m2/g). The APC was wet impregnated with ammonium heptamolybdate (AHM: 10 wt% Mo), dried and reduced in H2 at temperatures from 400 to 800 °C, to yield Mo2C/APC catalysts. Increased reduction temperature increased the Mo2C yield and the mesoporous volume of the Mo2C/APC. At a reduction temperature of 750 °C the mesopore volume of the catalyst doubled compared to the APC support and accounted for 37% of the total pore volume. Maintaining the final CHR temperature for 90 min further increased the Mo2C yield and mesoporosity of the catalyst. The role of Mo2C in the catalytic hydrogenation of the APC and mesopore generation is demonstrated. The activity of the Mo2C/carbon catalysts in the hydrodeoxygenation of 4-methyl phenol increased with increased CHR temperature and catalyst mesoporosity.

  7. A Facile Synthesis of Hollow Palladium/Copper Alloy Nanocubes Supported on N-Doped Graphene for Ethanol Electrooxidation Catalyst

    Directory of Open Access Journals (Sweden)

    Zhengyu Bai

    2015-04-01

    Full Text Available In this paper, a catalyst of hollow PdCu alloy nanocubes supported on nitrogen-doped graphene support (H-PdCu/ppy-NG is successfully synthesized using a simple one-pot template-free method. Two other catalyst materials such as solid PdCu alloy particles supported on this same nitrogen-doped graphene support (PdCu/ppy-NG and hollow PdCu alloy nanocubes supported on the reduced graphene oxide support (H-PdCu/RGO are also prepared using the similar synthesis conditions for comparison. It is found that, among these three catalyst materials, H-PdCu/ppy-NG gives the highest electrochemical active area and both the most uniformity and dispersibility of H-PdCu particles. Electrochemical tests show that the H-PdCu/ppy-NG catalyst can give the best electrocatalytic activity and stability towards the ethanol electrooxidation when compared to other two catalysts. Therefore, H-PdCu/ppy-NG should be a promising catalyst candidate for anodic ethanol oxidation in direct ethanol fuel cells.

  8. A low-crystalline ruthenium nano-layer supported on praseodymium oxide as an active catalyst for ammonia synthesis.

    Science.gov (United States)

    Sato, Katsutoshi; Imamura, Kazuya; Kawano, Yukiko; Miyahara, Shin-Ichiro; Yamamoto, Tomokazu; Matsumura, Syo; Nagaoka, Katsutoshi

    2017-01-01

    Ammonia is a crucial chemical feedstock for fertilizer production and is a potential energy carrier. However, the current method of synthesizing ammonia, the Haber-Bosch process, consumes a great deal of energy. To reduce energy consumption, a process and a substance that can catalyze ammonia synthesis under mild conditions (low temperature and low pressure) are strongly needed. Here we show that Ru/Pr 2 O 3 without any dopant catalyzes ammonia synthesis under mild conditions at 1.8 times the rates reported with other highly active catalysts. Scanning transmission electron micrograph observations and energy dispersive X-ray analyses revealed the formation of low-crystalline nano-layers of ruthenium on the surface of Pr 2 O 3 . Furthermore, CO 2 temperature-programmed desorption revealed that the catalyst was strongly basic. These unique structural and electronic characteristics are considered to synergistically accelerate the rate-determining step of NH 3 synthesis, cleavage of the N 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000

  9. Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst.

    Science.gov (United States)

    Yeow, Jonathan; Xu, Jiangtao; Boyer, Cyrille

    2016-06-08

    Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (λ = 460 nm, 0.7 mW/cm(2)), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

  10. Reverse Topotactic Transformation of a Cu–Zn–Al Catalyst during Wet Pd Impregnation : Relevance for the Performance in Methanol Synthesis from CO2/H2 Mixtures

    NARCIS (Netherlands)

    Fierro, J.L.G.; López Granados, M.; Melián-Cabrera, I.

    2002-01-01

    The effect of palladium metal on the performance of a CuO–ZnO–Al2O3 catalyst is studied for methanol synthesis by hydrogenation of carbon dioxide. The dramatic decrease in the methanol yield (in mol CH3OH/h · gcat) seen for the Pd-containing catalysts is discussed in terms of formation,

  11. Ultrasound-assisted synthesis of β-amino ketones via a Mannich reaction catalyzed by Fe3O4 magnetite nanoparticles as an efficient, recyclable and heterogeneous catalyst

    Directory of Open Access Journals (Sweden)

    Naghi Saadatjoo

    2017-02-01

    The present methodology offers several advantages, such as good yields, short reaction times and a recyclable catalyst with a very easy work up. In addition, the obtained results indicated that MNPs can be used as an effective and inexpensive catalyst for stereoselective synthesis of β-amino carbonyl by a one-pot three component condensation of aldehydes, ketones and amines.

  12. One-pot synthesis of well-defined polyether/polyester block copolymers and terpolymers by a highly efficient catalyst switch approach

    KAUST Repository

    Alamri, Haleema

    2016-04-20

    A highly efficient methodology, based on a novel catalyst switch approach with rapid crossover characteristics, was developed for the one-pot synthesis of block co/terpolymers of cyclic ethers and esters. This new approach, which takes advantage of one of the best catalysts for epoxide (t-BuP4) and cyclic ester (t-BuP2) polymerization, opens new horizons toward the synthesis of cyclic ether/ester complex macromolecular architectures. © The Royal Society of Chemistry 2016.

  13. One-pot synthesis of well-defined polyether/polyester block copolymers and terpolymers by a highly efficient catalyst switch approach

    KAUST Repository

    Alamri, Haleema; Hadjichristidis, Nikolaos

    2016-01-01

    A highly efficient methodology, based on a novel catalyst switch approach with rapid crossover characteristics, was developed for the one-pot synthesis of block co/terpolymers of cyclic ethers and esters. This new approach, which takes advantage of one of the best catalysts for epoxide (t-BuP4) and cyclic ester (t-BuP2) polymerization, opens new horizons toward the synthesis of cyclic ether/ester complex macromolecular architectures. © The Royal Society of Chemistry 2016.

  14. Cauliflower-like CuI nanostructures: Green synthesis and applications as catalyst and adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Yi [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); Gao Shuyan, E-mail: shuyangao@htu.cn [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); Li Zhengdao; Jia Xiaoxia; Chen Yanli [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China)

    2011-08-15

    Highlights: > In this study we report a green, environment-friendly, efficient, and direct one-step process for the preparation of CuI cauliflower. > The as-formed CuI cauliflower shows excellent catalytic activity for coupling reaction between benzylamine and iodobenzene. > The cauliflower-like CuI nanostructures have been successfully demonstrated as adsorbent for Cd (II) with high removal capacity. > To the best of our knowledge, it is the first report that nanostructured CuI acts as catalyst for coupling reaction and adsorbent for heavy metal ion. > It is also a good example for the organic combination of green chemistry and functional materials. - Abstract: Cauliflower-like CuI nanostructures is realized by an ampicillin-assisted clean, nontoxic, environmentally friendly synthesis strategy at room temperature. The morphology, composition, and phase structure of as-prepared powders were characterized by field emission scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results show that ampicillin plays dual roles, reducing and morphology-directing agents, in the formation of the products. A possible growth mechanism of the cauliflower-like CuI nanostructures is tentatively proposed. The preliminary investigations show that the cauliflower-like CuI structure not only exhibits high catalytic activity with respect to coupling reaction between benzylamine and iodobenzene but also possesses high removal capacity for Cd (II), which may be ascribed to the high specific surface area of the special configuration. To the best of our knowledge, it is the first report that cauliflower-like CuI nanoparticles act as catalyst for coupling reaction and adsorbent for heavy metal ion.

  15. Cauliflower-like CuI nanostructures: Green synthesis and applications as catalyst and adsorbent

    International Nuclear Information System (INIS)

    Jiang Yi; Gao Shuyan; Li Zhengdao; Jia Xiaoxia; Chen Yanli

    2011-01-01

    Highlights: → In this study we report a green, environment-friendly, efficient, and direct one-step process for the preparation of CuI cauliflower. → The as-formed CuI cauliflower shows excellent catalytic activity for coupling reaction between benzylamine and iodobenzene. → The cauliflower-like CuI nanostructures have been successfully demonstrated as adsorbent for Cd (II) with high removal capacity. → To the best of our knowledge, it is the first report that nanostructured CuI acts as catalyst for coupling reaction and adsorbent for heavy metal ion. → It is also a good example for the organic combination of green chemistry and functional materials. - Abstract: Cauliflower-like CuI nanostructures is realized by an ampicillin-assisted clean, nontoxic, environmentally friendly synthesis strategy at room temperature. The morphology, composition, and phase structure of as-prepared powders were characterized by field emission scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results show that ampicillin plays dual roles, reducing and morphology-directing agents, in the formation of the products. A possible growth mechanism of the cauliflower-like CuI nanostructures is tentatively proposed. The preliminary investigations show that the cauliflower-like CuI structure not only exhibits high catalytic activity with respect to coupling reaction between benzylamine and iodobenzene but also possesses high removal capacity for Cd (II), which may be ascribed to the high specific surface area of the special configuration. To the best of our knowledge, it is the first report that cauliflower-like CuI nanoparticles act as catalyst for coupling reaction and adsorbent for heavy metal ion.

  16. Fe_3O_4@B-MCM-41: A new magnetically recoverable nanostructured catalyst for the synthesis of polyhydroquinolines

    International Nuclear Information System (INIS)

    Abdollahi-Alibeik, Mohammad; Rezaeipoor-Anari, Ali

    2016-01-01

    Boron modified MCM-41 with magnetite core (Fe_3O_4@B-MCM-41) as a new magnetically recoverable heterogeneous catalyst was prepared and characterized by SEM, TEM, BET, XRD, VSM and FT-IR techniques. The catalytic activity of Fe_3O_4@B-MCM-41 was investigated in the four-component reaction of aldehyde, dimedone, active methylene compounds and ammonium acetate for the synthesis of polyhydroquinolines. According to optimization and characterization results the catalyst with Si:B:Fe_3O_4 mole composition of 40:4:1 has the best activity. The catalyst could be recovered easily by external magnet and has excellent reusability many times without significant decrease of activity. - Highlights: • Core–shell Fe_3O_4@MCM-41 nanoparticles modified by boron (Fe_3O_4@B-MCM-41). • Fe_3O_4@B-MCM-41 as reusable catalyst for the synthesis of polyhydroquinolines. • Characterization of Fe_3O_4@B-MCM-41 using SEM, TEM, BET, XRD and FT-IR techniques.

  17. Bismuth molybdate catalysts prepared by mild hydrothermal synthesis: Influence of pH on the selective oxidation of propylene

    DEFF Research Database (Denmark)

    Schuh, Kirsten; Kleist, Wolfgang; Høj, Martin

    2015-01-01

    A series of bismuth molybdate catalysts with relatively high surface area was prepared via mild hydrothermal synthesis. Variation of the pH value and Bi/Mo ratio during the synthesis allowed tuning of the crystalline Bi-Mo oxide phases, as determined by X-ray diffraction (XRD) and Raman...... spectroscopy. The pH value during synthesis had a strong influence on the catalytic performance. Synthesis using a Bi/Mo ratio of 1/1 at pH ≥ 6 resulted in γ-Bi2MoO6, which exhibited a better catalytic performance than phase mixtures obtained at lower pH values. However, a significantly lower catalytic...

  18. Solvent-Free Synthesis of Aryl Iodide Using Nano SiO2/HIO4 as a Reusable Acid Catalyst

    Directory of Open Access Journals (Sweden)

    A. Bamoniri

    2014-07-01

    Full Text Available An efficient and environmentally benign   method for the synthesis of aryl iodides have been developed by diazotization of aromatic amines with NaNO2 and nanosilica periodic acid (nano-SPIA as a green catalyst via grinding followed by a sandmeyer iodination by KI under solvent-free conditions at room temperature. The ensuing aryl diazonium salts supported on nano-SPIA were sufficiently stable to be kept at room temperature in the dry state. This method is a novel, efficient, eco-friendly route for solvent-free synthesis of aryl iodides.

  19. A study of Cu/ZnO/Al2O3 methanol catalysts prepared by flame combustion synthesis

    DEFF Research Database (Denmark)

    Jensen, Joakim Reimer; Johannessen, Tue; Wedel, Stig

    2003-01-01

    The flame combustion synthesis of Cu/ZnO/Al2O3 catalysts for the synthesis of methanol from CO, CO2 and H2 is investigated. The oxides are generated in a premixed flame from the acetyl-acetonate vapours of Cu, Zn and Al mixed with the fuel and air prior to combustion. The flame-generated powder...... temperature and quench-cooling of the flame tend to increase the dispersion of the phases and the specific surface area of the particles. Properties of both the ternary composition, the three binary compositions and the pure oxides are discussed. The calculation of simultaneous phase and chemical equilibrium...

  20. BF3.SiO2: an efficient catalyst for the synthesis of azo dyes at room temperature

    Directory of Open Access Journals (Sweden)

    Bi Bi Fatemeh Mirjalili

    2012-07-01

    Full Text Available A rapid one-pot method has been developed for the synthesis of azo dyes via ‎sequential diazotization–diazo coupling of aromatic amines with coupling agents at room ‎temperature in the presence of BF3.SiO2 as acidic catalyst. The obtained aryl diazonium salts bearing silica supported boron tri-flouride counter ion‎ was sufficiently stable to be kept at room ‎temperature in the dry state.‎

  1. Green and selective synthesis of N-substituted amides using water soluble porphyrazinato copper(II) catalyst

    International Nuclear Information System (INIS)

    Ghodsinia, Sara S.E.; Akhlaghinia, Batool; Eshghi, Hossein; Safaei, Elham

    2013-01-01

    N, N',N , N ' -Tetramethyl tetra-2,3-pyridinoporphyrazinato copper(II) methyl sulfate ([Cu(2,3-tmtppa)](MeSO 4 ) 4 ) efficiently catalyzed the direct conversion of nitriles to N-substituted amides. The one pot selective synthesis of the N-substituted amides from nitriles and primary amines was performed in refluxing H 2 O. The catalyst was recovered and reused at least four times, maintaining its efficiency. (author)

  2. Gold nanoparticles supported on titanium dioxide: an efficient catalyst for highly selective synthesis of benzoxazoles and benzimidazoles.

    Science.gov (United States)

    Tang, Lin; Guo, Xuefeng; Yang, Yu; Zha, Zhenggen; Wang, Zhiyong

    2014-06-11

    A highly efficient and selective reaction for the synthesis of 2-substituted benzoxazoles and benzimidazoles catalyzed by Au/TiO2 has been developed via two hydrogen-transfer processes. This reaction has a good tolerance to air and water, a wide substrate scope, and represents a new avenue for practical C-N and C-O bond formation. More importantly, no additional additives, oxidants and reductants are required for the reaction and the catalyst can be recovered and reused readily.

  3. On possibility of preparation of catalysts for ammonia synthesis based on cyanocomplexes of some d-metals

    International Nuclear Information System (INIS)

    Sergeeva, A.N.; Dovgej, V.V.; Pavlenko, L.I.; Zubritskaya, D.I.; Tkachenko, Zh.I.; Okorskaya, A.P.; Lyubchenko, Yu.A.

    1983-01-01

    The catalytic properties of the systems prepared on the basis of coordination cyanides of iron, ruthenium, osmium, rhenium, molydenum, vanadium and other d-metals in the ammonia synthesis reaction are studied. It has been found that thermal stability of catalytic systems containing vanadium and molybdenum is considerably higher than that of the industrial sample of similar type containing aluminium. The systems prepared on the basis of hexacyanoferrates, ruthenates and osmates can be referred to low-temperature type catalysts

  4. Preparation of Monodispersed Fe-Mo Nanoparticles as the Catalyst for CVD Synthesis of Carbon Nanotubes

    National Research Council Canada - National Science Library

    Li, Yan; Liu, Jie; Wang, Yongqian; Wang, Zhong L

    2001-01-01

    ...particles were systematically studied. The prepared nanoparticles were used as catalysts for single-walled carbon nanotube growth and the results indicate that there is an upper limit for the size of the catalyst particles to nucleate singlewalled carbon nanotubes.

  5. Sulfated polyborate: A mild, efficient catalyst for synthesis of N-tert ...

    Indian Academy of Sciences (India)

    chemsci

    trityl protected amides via Ritter reaction of nitriles with tertiary alcohols in the presence of a sulfated polyborate catalyst under solvent-free conditions is described. The catalyst has the advantage of Lewis as well as Bronsted acidity and.

  6. Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin.

    Science.gov (United States)

    Franco, Ana; De, Sudipta; Balu, Alina M; Garcia, Araceli; Luque, Rafael

    2017-01-01

    Vanillin is one of the most commonly used natural products, which can also be produced from lignin-derived feedstocks. The chemical synthesis of vanillin is well-established in large-scale production from petrochemical-based starting materials. To overcome this problem, lignin-derived monomers (such as eugenol, isoeugenol, ferulic acid etc.) have been effectively used in the past few years. However, selective and efficient production of vanillin from these feedstocks still remains an issue to replace the existing process. In this work, new transition metal-based catalysts were proposed to investigate their efficiency in vanillin production. Reduced graphene oxide supported Fe and Co catalysts showed high conversion of isoeugenol under mild reaction conditions using H 2 O 2 as oxidizing agent. Fe catalysts were more selective as compared to Co catalysts, providing a 63% vanillin selectivity at 61% conversion in 2 h. The mechanochemical process was demonstrated as an effective approach to prepare supported metal catalysts that exhibited high activity for the production of vanillin from isoeugenol.

  7. Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

    Directory of Open Access Journals (Sweden)

    Ana Franco

    2017-07-01

    Full Text Available Vanillin is one of the most commonly used natural products, which can also be produced from lignin-derived feedstocks. The chemical synthesis of vanillin is well-established in large-scale production from petrochemical-based starting materials. To overcome this problem, lignin-derived monomers (such as eugenol, isoeugenol, ferulic acid etc. have been effectively used in the past few years. However, selective and efficient production of vanillin from these feedstocks still remains an issue to replace the existing process. In this work, new transition metal-based catalysts were proposed to investigate their efficiency in vanillin production. Reduced graphene oxide supported Fe and Co catalysts showed high conversion of isoeugenol under mild reaction conditions using H2O2 as oxidizing agent. Fe catalysts were more selective as compared to Co catalysts, providing a 63% vanillin selectivity at 61% conversion in 2 h. The mechanochemical process was demonstrated as an effective approach to prepare supported metal catalysts that exhibited high activity for the production of vanillin from isoeugenol.

  8. Effect of iron promoter on structure and performance of CuMnZnO catalyst for higher alcohols synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Mingyue [Key Laboratory of Renewable Energy and Natural Gas Hydrate, Chinese Academy of Science, Guangzhou Guangdong 510640 (China); Guangzhou Institute of Energy Conversion, Chinese Academy of Science, Guangzhou Guangdong 510640 (China); Qiu, Minghuang [Key Laboratory of Renewable Energy and Natural Gas Hydrate, Chinese Academy of Science, Guangzhou Guangdong 510640 (China); Guangzhou Institute of Energy Conversion, Chinese Academy of Science, Guangzhou Guangdong 510640 (China); Graduate School of Chinese Academy of Science, Beijing 100049 (China); Wang, Tiejun [Key Laboratory of Renewable Energy and Natural Gas Hydrate, Chinese Academy of Science, Guangzhou Guangdong 510640 (China); Guangzhou Institute of Energy Conversion, Chinese Academy of Science, Guangzhou Guangdong 510640 (China); Ma, Longlong; Wu, Chuangzhi [Key Laboratory of Renewable Energy and Natural Gas Hydrate, Chinese Academy of Science, Guangzhou Guangdong 510640 (China); Guangzhou Institute of Energy Conversion, Chinese Academy of Science, Guangzhou Guangdong 510640 (China); Liu, Jianguo [Key Laboratory of Renewable Energy and Natural Gas Hydrate, Chinese Academy of Science, Guangzhou Guangdong 510640 (China); Guangzhou Institute of Energy Conversion, Chinese Academy of Science, Guangzhou Guangdong 510640 (China); Graduate School of Chinese Academy of Science, Beijing 100049 (China)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Incorporation of iron promotes the dispersion of catalyst particles. Black-Right-Pointing-Pointer Adding iron facilitates the separation of CuO from the Cu-Mn solid solution. Black-Right-Pointing-Pointer Both the copper and iron carbides are well dispersed in higher iron amount. Black-Right-Pointing-Pointer The selectivity to C{sub 2}{sup +}OH is promoted by increasing iron concentration. -- Abstract: Effect of iron promoter on the microstructures of CuMnZnO catalysts was investigated by N{sub 2} physical adsorption (BET), X-ray diffraction (XRD), and temperature-programmed reduction of hydrogen (H{sub 2}-TPR). Higher alcohols synthesis (HAS) was performed in a fixed bed reactor. The characterization results indicated that incorporation of iron in the CuMnZnO catalyst resulted in the increase of BET surface area and the dispersion of catalyst particles. Adding iron facilitated the formation of Fe-Mn solid solution and reduced the interaction between copper and manganese, which promoted the separation of CuO from the Cu-Mn solid solution and the reduction of the catalyst. In the HAS reaction, the catalytic activity of CO hydrogenation and the selectivity to C{sub 2}{sup +}OH and hydrocarbons presented an increasing trend with the increase in iron concentration, which may be attributed to the synergistic effect between the dispersed copper and iron carbides.

  9. Raising distillate selectivity and catalyst life time in Fischer-Tropsch synthesis by using a novel dual-bed reactor

    International Nuclear Information System (INIS)

    Tavasoli, A.; Sadaghiani, K.; Khodadadi, A. A.; Mortazavi, Y.

    2007-01-01

    In a novel dual bed reactor Fischer-Tropsch synthesis was studied by using two diff rent cobalt catalysts. An alkali-promoted cobalt catalyst was used in the first bed of a fixed-bed reactor followed by a Raiment promoted cobalt catalyst in the second bed. The activity, product selectivity and accelerated deactivation of the system were assessed and compared with a conventional single bed reactor system. The methane selectivity in the dual-bed reactor was about 18.9% less compared to that of the single-bed reactor. The C 5+ selectivity for the dual-bed reactor was 10.9% higher than that of the single-bed reactor. Accelerated deactivation of the catalysts in the dual-bed reactor was 42% lower than that of the single-bed reactor. It was revealed that the amount of catalysts activity recovery after regeneration at 400 d eg C in the dual-bed system is higher than that of the single-bed system

  10. Hydrogen or synthesis gas production via the partial oxidation of methane over supported nickel-cobalt catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Alaric C.W. [Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 (Singapore); Institute of Chemical and Engineering Sciences, 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Chen, Luwei; Lin, Jianyi [Institute of Chemical and Engineering Sciences, 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Kee Leong, Weng [Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 (Singapore); Johnson, Brian F.G.; Khimyak, Tetyana [University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge, UK CB2 1EW (United Kingdom)

    2007-05-15

    Activity, selectivity, and coking-resistance of a series of Ni{sub x}Co{sub y} (where x,y are the respective metal loadings of 0, 1, 2 or 3 wt.%; x+y=3) bimetallic catalysts supported on CaAl{sub 2}O{sub 4}/Al{sub 2}O{sub 3} have been studied for hydrogen/synthesis gas production via the catalytic partial oxidation (CPO) of methane. Catalysts were characterized by temperature programmed reduction (TPR), transmission electron microscopy (TEM) and X-ray fluorescence multi-element analysis (XRF). Their activity for the partial oxidation of methane to hydrogen and carbon monoxide (at 1 bar, gas hourly space velocity (GHSV) of 144,000cm{sup 3}g{sup -1}h{sup -1} and CH{sub 4}/O{sub 2} molar ratio of 2) was investigated, and coke deposited on the spent catalysts was studied by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and thermogravimetric analysis (TGA). The activity was found to decrease in the order of Ni{sub 2}Co>Ni{sub 3}>NiCo{sub 2}>>Co{sub 3}, while CO and H{sub 2} selectivities were found to be in the order ofNi{sub 2}Co>Ni{sub 3}{approx}NiCo{sub 2}>Co{sub 3}. Ni{sub 2}Co is also shown to be more resistant to coking as compared to Ni{sub 3}, which is a current catalyst of choice. Results show that not only does Ni{sub 2}Co have the highest activity and selectivity among all the catalysts tested, it is also relatively resistant to coking. This finding would be helpful for catalyst design to achieve high coking resistivity catalysts for hydrogen production from CPO of methane. (author)

  11. Synthesis of SnO{sub 2}-activated carbon fiber hybrid catalyst for the removal of methyl violet from water

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia, E-mail: mse_lij@ujn.edu.cn [School of Material Science and Engineering, University of Jinan, Jinan 250022 (China); Ng, Dickon H.L. [Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong (China); Song, Peng; Kong, Chao; Song, Yi [School of Material Science and Engineering, University of Jinan, Jinan 250022 (China)

    2015-04-15

    Graphical abstract: - Highlights: • A new biomass route for the synthesis of SnO{sub 2}/ACF hybrid catalyst was proposed. • The original fibrous structure of kapok fiber was retained in the SnO{sub 2}/ACF hybrid catalyst. • SnO{sub 2}/ACF hybrid catalyst exhibited high BET surface area (647–897 m{sup 2}/g) and large pore volume (0.36–0.56 cm{sup 3} g{sup −1}). • High microwave-induced catalytic activity for methyl violet degradation was obtained. - Abstract: SnO{sub 2}/activated carbon fiber (ACF) hybrid catalyst was synthesized from kapok precursor via a two-step process involving pore-fabricating and self-assembly of SnO{sub 2} nanoparticles. The morphology and phase structure of the obtained samples were characterized by X-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscopy and N{sub 2} adsorption-desorption isotherm. These results demonstrated that the synthesized SnO{sub 2}/ACF retained the hollow-fiber structure of kapok fibers. SnO{sub 2} nanoparticles dispersed uniformly over the ACF support. The obtained hybrid catalyst showed porous structure with high surface area (647–897 m{sup 2}/g) and large pore volume (0.36–0.56 cm{sup 3} g{sup −1}). In addition, the catalytic activities of the obtained samples for methyl violet degradation under microwave irradiation were also evaluated. It was found that the SnO{sub 2}/ACF catalyst exhibited high catalytic activity for methyl violet degradation due to the synergistic effect of microwave and SnO{sub 2}/ACF catalyst.

  12. Synthesis and Structure Characterization of Phenol-Urea-Formaldehyde Resins in the Presence of Magnesium Oxide as Catalyst

    Directory of Open Access Journals (Sweden)

    Dong-Bin Fan

    2014-08-01

    Full Text Available The objective of this research was to provide a useful approach of polymer synthesis for accelerating the fast cure of phenol-urea-formaldehyde (PUF resin as wood adhesive by optimizing its structure and composition. The PUF resins containing high contents of very reactive groups such as para-methylol groups were synthesized by reacting methylolurea, phenol, and formaldehyde in the presence of magnesium oxide (MgO as catalyst. The effects of synthesis parameters including F/(P + U, OH/P, and MgO/P mole ratios on the structure, composition, curing characteristics, and their relationships of PUF resins were investigated. The results indicated that MgO seemed to be an efficacious catalyst for PUF resin synthesis and promote its faster cure. The increase in the F/(P + U mole ratio or/and OH/P mole ratio appeared to be beneficial for the formation of para-methylol groups and cocondensed methylene linkages between phenolic methylol groups and urea units, and for the removal of unreacted urea. In case of Catalyst/P mole ratio, an appropriate dosage of added metal-ion was very important for synthesizing the high-content reactive groups of PUF resins, otherwise leading to the reverse effects.

  13. Moessbauer investigations of the Fe-Cu-Mn catalysts for Fischer-Tropsch synthesis

    International Nuclear Information System (INIS)

    Spanu, V.; Filoti, G.; Ilie, I.; Zamfirescu, E.

    1990-01-01

    In the selective process of the syngas conversion to synthetic gasoline a bifunctional catalytic system has to be used. It was obtained by combination a Fischer-Tropsch catalyst with the HZSM-5 zeolite. The phase compositions of the precursor and the fresh catalyst were established as well as the optimum thermal treatment. The catalyst was reduced in pure H 2 or in a H 2 +CO mixture. The influence of the reduction and reaction conditions on the catalyst structure was investigated. (orig.)

  14. Nano copper ferrite: A reusable catalyst for the synthesis of β, γ ...

    Indian Academy of Sciences (India)

    aCatalyst recovered by membrane filtration and washed with diethyl ether and then by distilled water. bYields compared to isolated products. From table 3, it is noticed that in some reactions the catalyst needs co-catalysts/additives. Some reac- tions need the acidic/basic workup to get the product. But here in this nano sized ...

  15. Green synthesis of 3,4-dihydropyrimidinones using nano Fe3O4@meglumine sulfonic acid as a new efficient solid acid catalyst under microwave irradiation

    Directory of Open Access Journals (Sweden)

    Leila Moradi

    2018-01-01

    Full Text Available Design, synthesis and characterization of nano Fe3O4@meglumine sulfonic acid as a new solid acid catalyst for the simple and green one pot multicomponent synthesis of 3,4-dihydropyrimidin-2(1H-ones/thiones was studied. New solid acid catalyst was prepared through a clean and simple protocol and characterized using FTIR, VSM, TGA, SEM, elemental analysis (CHN and XRD techniques. Heterogenization of homogeneous catalyst as a green approach is a useful method for enhancing the efficiency of catalyst. Presented study was a new method for attachment of homogeneous highly soluble catalyst (meglumine sulfate to the magnetite nanoparticle surfaces for preparing a heterogeneous and effective catalyst. Obtained heterogeneous and reusable solid acid catalyst has high performance in the synthesis of Biginelli compounds. The reaction was performed under microwave irradiation as a rapid and green condition. Easy work up as well as excellent yield (90–98% of products in short reaction times (40–200 s and reusable catalyst are the main advantages of presented procedure. Reaction products were characterized in details using physical and chemical techniques such as melting point, 1H NMR, 13C NMR and FTIR.

  16. Influence of the Synthesis Method for Pt Catalysts Supported on Highly Mesoporous Carbon Xerogel and Vulcan Carbon Black on the Electro-Oxidation of Methanol

    Directory of Open Access Journals (Sweden)

    Cinthia Alegre

    2015-03-01

    Full Text Available Platinum catalysts supported on carbon xerogel and carbon black (Vulcan were synthesized with the aim of investigating the influence of the characteristics of the support on the electrochemical performance of the catalysts. Three synthesis methods were compared: an impregnation method with two different reducing agents, sodium borohydride and formic acid, and a microemulsion method, in order to study the effect of the synthesis method on the physico-chemical properties of the catalysts. X-ray diffraction and transmission electron microscopy were applied. Cyclic voltammetry and chronoamperometry were used for studying carbon monoxide and methanol oxidation. Catalysts supported on carbon xerogel presented higher catalytic activities towards CO and CH3OH oxidation than catalysts supported on Vulcan. The higher mesoporosity of carbon xerogel was responsible for the favored diffusion of reagents towards catalytic centers.

  17. Asymmetric synthesis of L-[3-11C]phenylalanine using chiral hydrogenation catalysts

    International Nuclear Information System (INIS)

    Halldin, C.; Langstroem, B.

    1984-01-01

    The seven-step synthesis of L-[3- 11 C]phenylalanine using chiral diphosphines as ligands in rhodium catalysts is reported. [ 11 C]Benzaldehyde, prepared in a three-step reaction from [ 11 C]carbon dioxide, as reported elsewhere, was reacted with 2-phenyl-5-oxazolone or 2-(4-chloro)phenyl-5-oxazolone in the presence of the tertiary amine diazabicyclooctane (DABCO). The resultant [α- 11 C]-4-arylene-2-atyl-5-oxazolones were hydrogenated after ring opening, using the chiral rhodium complex of (R)-1,2-bis(diphenylphosphino)propane [(R)-PROPHOS] or (+)-2,3-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane [(+)-DIOP]. After removal of the amino protecting group, the labelled amino acid was obtained on purification by preparative LC in 10-15% radiochemical yield, and radiochemical purity higher than 95% from [ 11 C]carbon dioxide within 60 min. The optical purity of the products determined by the tRNA method and capillary GC, was 80 and 60% e.e., respectively (i.e. L/D=90/10 and 80/20). (author)

  18. Biogenic synthesis of palladium nanoparticles and their applications as catalyst and antimicrobial agent.

    Science.gov (United States)

    Hazarika, Munmi; Borah, Debajit; Bora, Popymita; Silva, Ana R; Das, Pankaj

    2017-01-01

    This paper describes a simple in-situ process of synthesizing highly dispersed palladium nanoparticles (PdNPs) using aqueous leaf extract of GarciniapedunculataRoxb as bio-reductant and starch (0.3%) as bio-stabilizer. The PdNPs are characterized by techniques like FTIR, TEM, SEM-EDX, XRD and XPS analysis. It is worthnoting thatwhen the synthesis of nanoparticles was carried out in absence of starch, agglomeration of particles has been noticed.The starch-assisted PdNPs showed excellent aqueous-phase catalytic activities for three important reactions: the Suzuki-Miyaura cross-coupling reactions of aryl halides (aryl bromides and iodides) with arylboronic acids; selective oxidations of alcohols to corresponding carbonyl compounds; and reduction of toxic Cr(VI) to nontoxic Cr(III). Our catalyst could be reused up to four cycles without much compromising with its activity. Furthermore, the material also demonstrated excellent antimicrobial and anti-biofilm activities against a novel multidrug resistant clinical bacterial isolate Cronobactersakazakii strain AMD04. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PdNPswere found to be 0.06 and 0.12 mM respectively.

  19. Biogenic synthesis of palladium nanoparticles and their applications as catalyst and antimicrobial agent.

    Directory of Open Access Journals (Sweden)

    Munmi Hazarika

    Full Text Available This paper describes a simple in-situ process of synthesizing highly dispersed palladium nanoparticles (PdNPs using aqueous leaf extract of GarciniapedunculataRoxb as bio-reductant and starch (0.3% as bio-stabilizer. The PdNPs are characterized by techniques like FTIR, TEM, SEM-EDX, XRD and XPS analysis. It is worthnoting thatwhen the synthesis of nanoparticles was carried out in absence of starch, agglomeration of particles has been noticed.The starch-assisted PdNPs showed excellent aqueous-phase catalytic activities for three important reactions: the Suzuki-Miyaura cross-coupling reactions of aryl halides (aryl bromides and iodides with arylboronic acids; selective oxidations of alcohols to corresponding carbonyl compounds; and reduction of toxic Cr(VI to nontoxic Cr(III. Our catalyst could be reused up to four cycles without much compromising with its activity. Furthermore, the material also demonstrated excellent antimicrobial and anti-biofilm activities against a novel multidrug resistant clinical bacterial isolate Cronobactersakazakii strain AMD04. The minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC of PdNPswere found to be 0.06 and 0.12 mM respectively.

  20. Mesoporous catalysts for the synthesis of clean diesel fuels by oligomerisation of olefins

    Energy Technology Data Exchange (ETDEWEB)

    Catani, Roberto; Rossini, Stefano [Snamprogetti SpA, Via F. Maritano 26, 20092 , MI S. Donato Milanese (Italy); Mandreoli, Monica; Vaccari, Angelo [Dipartimento di Chimica Industriale e dei Materiali, Universita di Bologna, INSTM-UdR di Bologna, Viale del Risorgimento 4, 40136 Bologna (Italy)

    2002-07-03

    Si/Al MCM-41 type mesoporous compounds, as such or containing small amounts of metal (Ni, Rh or Pt), were investigated in the synthesis of clean diesel fuels by oligomerisation of orphan olefin streams. Very good catalytic performances were obtained with C{sub 4} and C{sub 5} olefins, while almost no conversion occurred with ethylene. The activity increased with increasing reaction pressure, temperature and contact time, while high Si/Al ratios had a negative effect on both activity and catalyst stability. The presence of small amount of metal inside the mesoporous structure did not significantly modify the catalytic activity, although specific effects were detected for each element. Since the evaluation of the cetane number by H-NMR gave rise to values about 20% lower than the actual value, a new and more complex algorithm is proposed to calculate the cetane number. Using the proposed algorithm, a good correlation index was found between calculated and motor values for pure compounds. Further study is necessary to move from pure compounds to experimental mixtures.

  1. Synthesis of biodiesel using local natural zeolite as heterogeneous anion exchange catalyst

    Science.gov (United States)

    Hartono, R.; Wijanarko, A.; Hermansyah, H.

    2018-04-01

    Production of biodiesel using homogen catalyst: alkaline catalysts, acid catalysts, biocatalysts, and supercritical methanol are very inefficient, because these catalysts have a very high cost production of biodiesel and non-ecofriendly. The heterogeneous catalyst is then used to avoid adverse reaction of biodiesel production. The heterogeneous catalysts used is ion exchanger using natural zeolit catalists bayah banten (ZABBrht) and macroporous lewatit that can be used to produce biodiesel in the solid phase so that the separation is easier and can be used repeatedly. The results of biodiesel reach its optimum in engineering ion exchange catalyst natural zeolit bayah and macroporous lewatit which has been impregnated and calcinated at temperature 60 °C at reaction time 2 hours, are 94.8% and 95.24%, using 100 gr.KOH/100 mL Aquadest.

  2. Synthesis of carbon nanotubes by CCVD of natural gas using hydrotreating catalysts

    Directory of Open Access Journals (Sweden)

    Ahmed E. Awadallah

    2012-12-01

    Full Text Available Carbon nanotubes have been successfully synthesized using the catalytic chemical vapor deposition (CCVD technique over typical refining hydrotreating catalysts (hydrodesulfurization and hydrodenitrogenation containing Ni–Mo and Co–Mo supported on Al2O3 catalysts at 700°C in a fixed bed horizontal reactor using natural gas as a carbon source. The catalysts and the as-grown CNTs were characterized by transmission electron microscopy, HRTEM, X-ray diffraction patterns, EDX and TGA–DTG. The obtained data clarified that the Ni–Mo catalyst gives higher yield, higher purity and selectivity for CNTs compared to Co–Mo catalyst. XRD, TEM and TGA reveal also that the Ni–Mo catalyst produces mostly CNTs with different diameters whereas the Co–Mo catalyst produces largely amorphous carbon.

  3. In situ Generated Ruthenium Catalyst Systems Bearing Diverse N-Heterocyclic Carbene Precursors for Atom-Economic Amide Synthesis from Alcohols and Amines.

    Science.gov (United States)

    Cheng, Hua; Xiong, Mao-Qian; Cheng, Chuan-Xiang; Wang, Hua-Jing; Lu, Qiang; Liu, Hong-Fu; Yao, Fu-Bin; Chen, Cheng; Verpoort, Francis

    2018-02-16

    The transition-metal-catalyzed direct synthesis of amides from alcohols and amines is herein demonstrated as a highly environmentally benign and atom-economic process. Among various catalyst systems, in situ generated N-heterocyclic carbene (NHC)-based ruthenium (Ru) halide catalyst systems have been proven to be active for this transformation. However, these existing catalyst systems usually require an additional ligand to achieve satisfactory results. In this work, through extensive screening of a diverse variety of NHC precursors, we discovered an active in situ catalyst system for efficient amide synthesis without any additional ligand. Notably, this catalyst system was found to be insensitive to the electronic effects of the substrates, and various electron-deficient substrates, which were not highly reactive with our previous catalyst systems, could be employed to afford the corresponding amides efficiently. Furthermore, mechanistic investigations were performed to provide a rationale for the high activity of the optimized catalyst system. NMR-scale reactions indicated that the rapid formation of a Ru hydride intermediate (signal at δ=-7.8 ppm in the 1 H NMR spectrum) after the addition of the alcohol substrate should be pivotal in establishing the high catalyst activity. Besides, HRMS analysis provided possible structures of the in situ generated catalyst system. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Effects of calcination and activation conditions on ordered mesoporous carbon supported iron catalysts for production of lower olefins from synthesis gas

    NARCIS (Netherlands)

    Oschatz, M; van Deelen, T W; Weber, J L; Lamme, W S; Wang, G; Goderis, B; Verkinderen, O; Dugulan, A I; de Jong, K P

    2016-01-01

    Lower C2–C4 olefins are important commodity chemicals usually produced by steam cracking of naphtha or fluid catalytic cracking of vacuum gas oil. The Fischer–Tropsch synthesis of lower olefins (FTO) with iron-based catalysts uses synthesis gas as an alternative feedstock. Nanostructured carbon

  5. Synthesis of dimethyl carbonate (DMC) by oxidative carbonylation of methanol using polymer-supported CuCl{sub 2} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Y. [Daicel Chemical Industries, Ltd., Hyogo (Japan). Research Center; Kobe University, Kobe (Japan); Kagotani, M. [Daicel Chemical Industries, Ltd., Hyogo (Japan). Research Center; Soma, Y. [Osaka National Research Institute, Osaka (Japan)

    2000-01-01

    Polymer, including 2,2'-bipyridine, poly(4-methyl-4'-vinyl-2,2'-bipyridine)(Pvbpy), was investigated for the synthesis of dimethyl carbonate (DMC) as a support for CuCl{sub 2}, by oxidative carbonylation of methanol in the liquid-phase. The CuCl{sub 2} complex (Pvbpy-CuCl{sub 2}) was insoluble in methanol, and the reaction system was heterogeneous. The Pvbpy-CuCl{sub 2} catalyst showed considerable catalytic activity (DMC yield: 44.4 % and DMC selectivity: 9206 %, at methanol conversion: 1.79 %), which is comparable to the previously reported data of poly (vinylpyridine) (PVP)-CuCl{sub 2} catalyst; the Pvbpy-CuCl{sub 2} catalyst could be recycled after filtration and washing thrice, provided, not having lost activity. The corrosion originating from Cl{sup -} was greatly improved by immobilizing the CuCl{sub 2} by Pvbpy. Elimination of CuCl{sub 2} from the Pvbpy support was observed during the reaction. In the first reaction, about 38 % of the initially supported Cl was released, and in the second and the third reactions, most of the Cl was retained. The rate of corrosion of stainless steels in the first use of the catalyst (0.6 mg h{sup -1} for HC276) was greater than that in the rate of the second and the third uses (<0.1 mg h{sup -1}). These results are closely related to the amount of Cl{sup -} released from the Pvbpy support, which demonstrates that the main cause of corrosion in the catalytic system is Cl{sup -} released from the Pvbpy-CuCl{sub 2} catalyst. From XPS study of the catalyst, it became obvious that Cu(2) was gradually reduced to Cu(1) during the reaction. (author)

  6. Highly efficient water-mediated approach to access benzazoles: metal catalyst and base-free synthesis of 2-substituted benzimidazoles, benzoxazoles, and benzothiazoles.

    Science.gov (United States)

    Bala, Manju; Verma, Praveen Kumar; Sharma, Deepika; Kumar, Neeraj; Singh, Bikram

    2015-05-01

    An efficient water-catalyzed method has been developed for the synthesis of 2-substituted benzimidazoles, benzoxazoles, and benzothiazoles in one step. The present method excludes the usage of toxic metal catalysts and bases to produce benzazoles in good to excellent yields. An efficient and versatile water-mediated method has been established for the synthesis of various 2-arylbenzazoles. The present protocol excludes the usage of any catalyst and additive provided excellent selectivities and yields with high functional group tolerance for the synthesis of 2-arylated benzimidazoles, benzoxazoles, and benzothiazoles. Benzazolones were also synthesized using similar reaction protocol.

  7. Synthesis of new annulated pyrano[2,3-d]pyrimidine derivatives using organo catalyst (DABCO in aqueous media

    Directory of Open Access Journals (Sweden)

    Ajmal R. Bhat

    2017-01-01

    Full Text Available A selective method for the synthesis of annulated pyrano[2,3-d]pyrimidines has been developed. It was shown that base catalysis is more efficient in this reaction, rather than acid catalysis as it is believed that 1,4-diazabicyclo[2.2.2]octane (DABCO is N-type base catalyst used for the synthesis of pyrano[2,3-d]pyramidine derivatives via one-pot three component condensation reactions of various aromatic aldehydes, active methylene compounds and barbituric acid in aqueous ethanol carried at normal temperature. The potential application of DABCO in organic synthesis increasing rapidly because of its reaction simplicity, less pollution, and minimum reaction time, high yields of the biological active products, uses less toxic solvents and low cost chemicals.

  8. Mesoporous silica materials modified with alumina polycations as catalysts for the synthesis of dimethyl ether from methanol

    Energy Technology Data Exchange (ETDEWEB)

    Macina, Daniel; Piwowarska, Zofia; Tarach, Karolina; Góra-Marek, Kinga [Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków (Poland); Ryczkowski, Janusz [Maria Curie Skłodowska University, Faculty of Chemistry, Maria Curie-Skłodowska 2, 20-031 Lublin (Poland); Chmielarz, Lucjan, E-mail: chmielar@chemia.uj.edu.pl [Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków (Poland)

    2016-02-15

    Highlights: • Deposition of alumina ologoctaions on mesoporous silicas modified with surface −SO{sub 3}H groups. • Alumina aggregates generated acid properties in the silica supports. • Alumina modified SBA-15 and MCF were active and selective catalysts in DME synthesis. - Abstract: Mesoporous silica materials (SBA-15 and MCF) were used as catalytic supports for the deposition of aggregated alumina species using the method consisting of the following steps: (i) anchoring 3-(mercaptopropyl)trimethoxysilane (MPTMS) on the silica surface followed by (ii) oxidation of −SH to−SO{sub 3}H groups and then (iii) deposition of aluminum Keggin oligocations by ion-exchange method and (iv) calcination. The obtained samples were tested as catalysts for synthesis of dimethyl ether from methanol. The modified silicas were characterized with respect to the ordering of their porous structure (XRD), textural properties (BET), chemical composition (EDS, CHNS), structure ({sup 27}Al NMR, FTIR) and location of alumina species (EDX-TEM), surface acidity (NH{sub 3}-TPD, Py-FTIR) and thermal stability (TGA). The obtained materials were found to be active and selective catalysts for methanol dehydration to dimethyl ether (DME) in the MTD process (methanol-to-dimethyl ether).

  9. Immobilization of Highly Effective Palladium Catalyst onto Poly(4-Vinylpyridine): Synthesis and Characterization

    International Nuclear Information System (INIS)

    Siti Kamilah Che Soh; Intan Shafinass Kassim; Siti Aminah Jusoh; Mustaffa Samsuddin

    2016-01-01

    A commonly known weakness of homogeneous catalysts is the difficulty to recover the active catalyst from the product. Due to the disadvantage, the designing of supported catalyst has been approached to overcome the separation difficulty of the palladium-based homogeneous catalyst. New polymer supported N 2 O 2 metal complex was successfully immobilized by mixing of poly(4-vinylpyridine) with palladium(II) complex in the presence of ethyl acetate as solvent. Then, the reaction was stirred for 72 hours at room temperature to form corresponding P 4 VP-Pd catalyst. The properties of immobilized catalyst were characterized by various techniques such as fourier transform infrared (FTIR), thermogravimetric (TGA), X-ray diffraction (XRD), scanning electron microscopy/ energy dispersive X-ray (SEM/ EDX) and inductively coupled plasma-optical emission (ICP-OES) spectroscopy. (author)

  10. Hydrothermal Synthesis of Nanostructured Manganese Oxide as Cathodic Catalyst in a Microbial Fuel Cell Fed with Leachate

    Science.gov (United States)

    Haoran, Yuan; Lifang, Deng; Tao, Lu; Yong, Chen

    2014-01-01

    Much effort has been devoted to the synthesis of novel nanostructured MnO2 materials because of their unique properties and potential applications as cathode catalyst in Microbial fuel cell. Hybrid MnO2 nanostructures were fabricated by a simple hydrothermal method in this study. Their crystal structures, morphology, and electrochemical characters were carried out by FESEM, N2-adsorption-desorption, and CV, indicating that the hydrothermally synthesized MnO2 (HSM) was structured by nanorods of high aspect ratio and multivalve nanoflowers and more positive than the naturally synthesized MnO2 (NSM), accompanied by a noticeable increase in oxygen reduction peak current. When the HSM was employed as the cathode catalyst in air-cathode MFC which fed with leachate, a maximum power density of 119.07 mW/m2 was delivered, 64.68% higher than that with the NSM as cathode catalyst. Furthermore, the HSM via a 4-e pathway, but the NSM via a 2-e pathway in alkaline solution, and as 4-e pathway is a more efficient oxygen reduction reaction, the HSM was more positive than NSM. Our study provides useful information on facile preparation of cost-effective cathodic catalyst in air-cathode MFC for wastewater treatment. PMID:24723824

  11. Synthesis and Characterization of Silicotungstic Acid Nanoparticles Via Sol Gel Technique as a Catalyst in Esterification Reaction

    International Nuclear Information System (INIS)

    Wan Nor Roslam Wan Ishak; Manal Ismail

    2011-01-01

    The purpose of this work is to study the synthesis, characterization and catalytic performance of silicotungstic acid-silica sol gel (STA-SG) as acid catalyst in esterification reaction. The activity and selectivity of STA-SG have been investigated and compared to the STA bulk (STAB) and sulphuric acid (H 2 SO 4 ). The synthesized catalysts were characterized by various techniques shown that the STA-SG catalyst is relatively high in surface area compared to STAB of 460.11 m 2 /g and 0.98 m 2 /g, respectively. From the XPS analyses, there was a significant formation of W-O-Si, W-O-W and Si-O-Si bonding in STA-SG compared to that in STAB. Both the H 2 SO 4 and the STAB gave high conversion of 100 % and 98 %, while lower selectivity of glycerol monooleate (GMO) with 81.6 % and 89.9 %, respectively. On the contrary, the STA-SG enabled a conversion of 94 %, while significantly higher GMO selectivity of 95 % rendering it the more efficient acid catalyst. (author)

  12. Antisolvent Precipitation for the Synthesis of Monodisperse Mesoporous Niobium Oxide Spheres as Highly Effective Solid Acid Catalysts

    KAUST Repository

    Li, Cheng Chao; Dou, Jian; Chen, Luwei; Lin, Jianyi; Zeng, Hua Chun

    2012-01-01

    We have developed a low-cost reaction protocol to synthesize mesoporous Nb 2O 5-based solid acid catalysts with external shape control. In the synthesis, monodisperse glycolated niobium oxide spheres (GNOS) were prepared by means of a simple antisolvent precipitation approach and subsequently converted to mesoporous niobium oxide spheres (MNOS) with a large surface area of 312m 2g -1 by means of the hydrothermal treatment. The antisolvent acetone used to obtain GNOS was recovered through distillation at high purity. The obtained mesoporous MNOS were functionalized further with sulfate anions at different temperatures or incorporated with tungstophosphoric acid to obtain recyclable solid acid catalysts. These MNOS-based catalysts showed excellent performance in a wide range of acid-catalyzed reactions, such as Friedel-Crafts alkylation, esterification, and hydrolysis of acetates. As they are monodisperse spheres with diameters in the submicrometer range, the catalysts can be easily separated and reused. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Antisolvent Precipitation for the Synthesis of Monodisperse Mesoporous Niobium Oxide Spheres as Highly Effective Solid Acid Catalysts

    KAUST Repository

    Li, Cheng Chao

    2012-03-20

    We have developed a low-cost reaction protocol to synthesize mesoporous Nb 2O 5-based solid acid catalysts with external shape control. In the synthesis, monodisperse glycolated niobium oxide spheres (GNOS) were prepared by means of a simple antisolvent precipitation approach and subsequently converted to mesoporous niobium oxide spheres (MNOS) with a large surface area of 312m 2g -1 by means of the hydrothermal treatment. The antisolvent acetone used to obtain GNOS was recovered through distillation at high purity. The obtained mesoporous MNOS were functionalized further with sulfate anions at different temperatures or incorporated with tungstophosphoric acid to obtain recyclable solid acid catalysts. These MNOS-based catalysts showed excellent performance in a wide range of acid-catalyzed reactions, such as Friedel-Crafts alkylation, esterification, and hydrolysis of acetates. As they are monodisperse spheres with diameters in the submicrometer range, the catalysts can be easily separated and reused. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Ferromagnetic resonance of cobalt nanoparticles used as a catalyst for the carbon nanotubes synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Duraia, El-Shazly M. [Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt); Al-Farabi Kazakh National University, Almaty (Kazakhstan); Institute of Physics and Technology, Almaty (Kazakhstan)], E-mail: duraia_physics@yahoo.com; Abdullin, Kh.A. [Institute of Physics and Technology, Almaty (Kazakhstan)

    2009-12-15

    Catalyst is considered to be the most crucial parameter for the growth of carbon nanotubes. In this work we study the ferromagnetic resonance (FMR) spectra of the catalyst nanoclusters. Moreover we report for the first time the angle FMR studies of catalyst particles with and without CNT layer. The dependencies of the FMR spectra, X-ray diffraction (XRD) patterns, Raman spectra and morphology of the CNT layers on the growth conditions are discussed.

  15. Synthesis of Acrolein from Glycerol Using FePO4 Catalyst in Liquid Phase Dehydration

    Directory of Open Access Journals (Sweden)

    Akhmad Zainal Abidin

    2016-02-01

    Full Text Available Acrolein is currently produced using propylene from crude oil while its price and scarcity are increasing. A renewable material such as glycerol is an attractive alternative for acrolein production. It can be obtained from crude palm oil (CPO and is a byproduct of biodiesel production. Besides being able to compete economically, glycerol is an environmentally friendly material. The purpose of this study is to synthesize acrolein from glycerol using FePO4 catalyst in liquid phase dehydration. The catalyst was prepared by three different methods: hydrothermal (catalyst A, deposition at Fe/P = 1.15 (catalyst B, and deposition at Fe/P = 1.20 (catalyst C. The experimental reaction temperature was varied at 220, 240 and 260 °C under constant atmospheric pressure. The results showed that catalyst C provided the best yield (91%, followed by catalyst A (90% and catalyst B (82%. The increasing reaction temperature showed a tendency to increase the yield of acrolein, while the presence of oxygen reduced the yield of acrolein and allowed the reaction to produce more side products such as glycerol propanal, acetaldehyde, and propionate. Catalyst reuse without any regeneration resulted in a yield profile of acrolein that continued to decline.

  16. Synthesis of CaO-CeO2 catalysts by soft template method for biodiesel production

    Science.gov (United States)

    Zheng, Y. C.; Yu, X. H.; Yang, J.

    2017-06-01

    Biodiesel has recently gained extensive attention. Catalysts play an important role in producing biodiesel by transesterification reaction. In this study, CaO-CeO2 catalysts are developed as the solid base catalyst. Using PDMS-PEO as a structure-directing agent, the prepared CaO-CeO2 catalysts have a three-dimensional interconnected porous structure, which benefits the transesterification reaction. While the added Ce slightly decreases the catalytic activity, the stability of the catalyst shows remarkable improvement. Considering the catalytic activity and stability, the best catalyst is determined to be catalyst 0.15-1073 (Ce/Ca molar ratio of 0.15 and calcination temperature of 1073 K). Under optimum reaction conditions, the biodiesel yield reaches to 97.5% and metal leaching is 117.7 ppm. For catalyst 0.15-1073 regenerated after four reaction cycles, the biodiesel yield is 94.1%. The results reveal that the CaO-CeO2 catalyst has good potential for application in large-scale biodiesel production in the future.

  17. Synthesis and Characterization of Tin (IV Tungstate Nanoparticles – A Solid Acid Catalyst

    Directory of Open Access Journals (Sweden)

    Manoj Sadanandan

    2012-12-01

    Full Text Available Tin (IV tungstate, a tetravalent metal acid salt was synthesized in the nanoform by chemical coprecipitation method using EDTA as capping agent. The material was found to be stable in mineral acids, bases and organic solvents except  in HF and aquaregia. The material was characterized using EDS, TG/DTA, FTIR, XRD, SEM, HRTEM and BET surface area measurement. The molecular formula of the compound is 2SnO2 3WO3.5H2O determined from elemental analysis using TG/DTA. Surface morphology and particle size were obtained using SEM and HRTEM. The surface area was found to be 205-225m2/g. The Na+ exchange capacity found to be 3.8 meq/g, indicates the presence of surface hydroxyl group and hence the presence of Bronsted acid sites. The catalytic activity of the material was tested by using esterification and oxidation as model reactions. For the esterification of different alcohols, the percentage yield was found to be high for n-alcohol compared to isomeric alcohols. Oxidation of benzyl alcohol gives benzaldehyde and benzoic acid as the only products. Copyright © 2012 by BCREC UNDIP. All rights reservedReceived: 12nd June 2012, Revised: 23rd July 2012, Accepted: 29th July 2012[How to Cite: S. Manoj, R. Beena, (2012. Synthesis and Characterization of tin(IV Tungstate Nanoparticles – A Solid Acid Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (2: 105-111. doi:10.9767/bcrec.7.2.3622.105-111] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3622.105-111 ] | View in 

  18. Microwave-Assisted Synthesis of Nanoporous Aluminum-Based Coordination Polymers as Catalysts for Selective Sulfoxidation Reaction

    Directory of Open Access Journals (Sweden)

    Madhan Vinu

    2017-10-01

    Full Text Available A series of aluminum-based coordination polymers or metal–organic frameworks (Al–MOFs, i.e., DUT-4, DUT-5, MIL-53, NH2-MIL-53, and MIL-100, have been facile prepared by microwave (MW-assisted reactions and used as catalysts for selective sulfoxidation reactions. The MW-assisted synthesis drastically reduced the reaction time from few days to hours. The prepared MOFs have smaller and uniform particle sizes and better yield compared to conventional hydrothermal method. Furthermore, the Al–MOFs have been successfully demonstrated as catalysts in oxidation reaction of methyl phenyl sulfide with H2O2 as oxidant, even under mild conditions, with more than 95% conversion.

  19. A Mixed-Ligand Chiral Rhodium(II) Catalyst Enables the Enantioselective Total Synthesis of Piperarborenine B.

    Science.gov (United States)

    Panish, Robert A; Chintala, Srinivasa R; Fox, Joseph M

    2016-04-11

    A novel, mixed-ligand chiral rhodium(II) catalyst, Rh2(S-NTTL)3(dCPA), has enabled the first enantioselective total synthesis of the natural product piperarborenine B. A crystal structure of Rh2(S-NTTL)3(dCPA) reveals a "chiral crown" conformation with a bulky dicyclohexylphenyl acetate ligand and three N-naphthalimido groups oriented on the same face of the catalyst. The natural product was prepared on large scale using rhodium-catalyzed bicyclobutanation/ copper-catalyzed homoconjugate addition chemistry in the key step. The route proceeds in ten steps with an 8% overall yield and 92% ee. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Solvent-Free Biginelli Condensation using Tungstate Sulfuric Acid: a Powerful and Reusable Catalyst for Selective Synthesis

    Directory of Open Access Journals (Sweden)

    Rezvan Rezaee Nasab

    2014-07-01

    Full Text Available Tungstate sulfuric acid (TSA has been prepared and used as a recyclable catalyst for the Biginelli syn-thesis of some biologically active quinazolinones/thiones under solvent-free conditions. This method has advantages such as the avoidance of organic solvents, high yield of pure products, short reaction times, and operational simplicity.  © 2014 BCREC UNDIP. All rightsReceived: 28th April 2014; Revised: 15th May 2014; Accepted: 26th May 2014[ How to Cite: Nasab, R.R., Karami, B., Khodabakhshi, S. (2014. Selective Solvent‐free Biginelli Condensation using Tungstate Sulfuric Acid as Powerful and Reusable Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (2: 142-154. (doi:10.9767/bcrec.9.2.6794.148-154][ Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.2.6794.148-154

  1. Synthesis of Single-Walled Carbon Nanotubes: Effects of Active Metals, Catalyst Supports, and Metal Loading Percentage

    Directory of Open Access Journals (Sweden)

    Wei-Wen Liu

    2013-01-01

    Full Text Available The effects of active metals, catalyst supports, and metal loading percentage on the formation of single-walled carbon nanotubes (SWNTs were studied. In particular, iron, cobalt, and nickel were investigated for SWNTs synthesis. Iron was found to grow better-quality SWNTs compared to cobalt and nickel. To study the effect of catalyst supports, magnesium oxide, silicon oxide, and aluminium oxide were chosen for iron. Among the studied supports, MgO was identified to be a suitable support for iron as it produced SWNTs with better graphitisation determined by Raman analysis. Increasing the iron loading decreased the quality of SWNTs due to extensive agglomeration of the iron particles. Thus, lower metal loading percentage is preferred to grow better-quality SWNTs with uniform diameters.

  2. Preferential synthesis of (6,4) single-walled carbon nanotubes by controlling oxidation degree of Co catalyst.

    Science.gov (United States)

    Xu, Bin; Kaneko, Toshiro; Shibuta, Yasushi; Kato, Toshiaki

    2017-09-11

    Chirality-selective synthesis of single-walled carbon nanotubes (SWNTs) has been a research goal for the last two decades and is still challenging due to the difficulty in controlling the atomic structure in the one-dimensional material. Here, we develop an optimized approach for controlling the chirality of species by tuning the oxidation degree of Co catalyst. Predominant synthesis of (6,4) SWNTs is realized for the first time. The detailed mechanism is investigated through a systematic experimental study combined with first-principles calculations, revealing that the independent control of tube diameter and chiral angle achieved by changing the binding energy between SWNTs (cap and tube edge) and catalyst causes a drastic transition of chirality of SWNTs from (6,5) to (6,4). Since our approach of independently controlling the diameter and chiral angle can be applied to other chirality species, our results can be useful in achieving the on-demand synthesis of specific-chirality SWNTs.

  3. Alkaline leaching for synthesis of improved Fe-ZSM5 catalysts

    NARCIS (Netherlands)

    Espinosa, S; Mentruit, C; Kapteijn, F; Moulijn, JA; Melián-Cabrera, I.

    Fe-ZSM5 catalysts were fully Fe-exchanged by pretreating the parent zeolite with base a solution prior to the Fe-exchange. The catalysts prepared in this way showed very low amount of inactive FeOx and improved performance in N2O decomposition. Alkaline leaching breaks down the zeolite crystals -

  4. Confined-interface-directed synthesis of Palladium single-atom catalysts on graphene/amorphous carbon

    DEFF Research Database (Denmark)

    Xi, Jiangbo; Sun, Hongyu; Zhang, Zheye

    2018-01-01

    The maximized atomic efficiency of supported catalysts is highly desired in heterogeneous catalysis. Therefore, the design and development of active, stable, and atomic metal-based catalysts remains a formidable challenge. To tackle these problems, it is necessary to investigate the interaction b...

  5. A novel method for fabrication of Fe catalyst used for the synthesis of ...

    Indian Academy of Sciences (India)

    Administrator

    served by Perez-Cabero et al (2003) with the iron–silica catalysts with higher iron ... important factor in CNT growth and catalysts with large particle sizes have been .... A drop of the dispersed suspension was placed on a microgrid coated with ...

  6. Immobilised Homogeneous Catalysts for Sequential Fine Chemical Synthesis : Functionalised Organometallics for Nanotechnology

    NARCIS (Netherlands)

    McDonald, A.R.

    2008-01-01

    The work described in this thesis has demonstrated the application of heterogenised homogeneous catalysts. We have shown that by coupling a homogeneous catalyst to a heterogeneous support we could combine the benefits of two major fields of catalysis: retain the high selectivity of homogeneous

  7. SYNTHESIS OF OXIMES WITH THE DOPED POTASSIUM FLUORIDE ANIMAL BONE MEAL AS A CATALYST

    Directory of Open Access Journals (Sweden)

    M. AIT TALEB

    2017-12-01

    Full Text Available The potassium fluoride doped Animal Bone Meal (KF/ABM was prepared and characterized using several techniques to identify the structural properties. After, it has been used as a new and eco-friendly catalyst for the preparation of from aldehydes and ketones oximes under solvent-free conditions. It is clearly shown that this reaction (using this catalyst can lead to the corresponding oximes in good yields (80 % to excellent yields (96 %. In the case of dissymmetric aldehydes and ketones, this catalyst can lead to a mixture of Z- and E- isomers (Z/E = 86/14–90/10. The remarkable advantages of this catalyst are high conversion, short reaction times, cleaner reaction profiles, reusability up to 8 times without significant loss of activity, and reduction in catalyst toxicity.

  8. Green and selective synthesis of N-substituted amides using water soluble porphyrazinato copper(II) catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Ghodsinia, Sara S.E.; Akhlaghinia, Batool; Eshghi, Hossein, E-mail: akhlaghinia@um.ac.ir [Ferdowsi University of Mashhad (Iran, Islamic Republic of). Faculty of Sciences. Department of Chemistry; Safaei, Elham [Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan (Iran, Islamic Republic of). Department of Chemistry

    2013-06-15

    N, N',N{sup ,} N{sup '}-Tetramethyl tetra-2,3-pyridinoporphyrazinato copper(II) methyl sulfate ([Cu(2,3-tmtppa)](MeSO{sub 4}){sub 4}) efficiently catalyzed the direct conversion of nitriles to N-substituted amides. The one pot selective synthesis of the N-substituted amides from nitriles and primary amines was performed in refluxing H{sub 2}O. The catalyst was recovered and reused at least four times, maintaining its efficiency. (author)

  9. Enantioselective Alkylation of 2-Oxindoles Catalyzed by a Bifunctional Phase-Transfer Catalyst: Synthesis of (-)-Debromoflustramine B.

    Science.gov (United States)

    Craig, Ryan; Sorrentino, Emiliano; Connon, Stephen J

    2018-03-26

    A new bifunctional phase-transfer catalyst that employs hydrogen bonding as a control element was developed to promote efficient enantioselective S N 2 reactions for the construction all-carbon quaternary stereocenters in high yield and excellent enantioselectivity (up to 97 % ee) utilizing the alkylation of a malleable oxindole substrate. The utility of the methodology was demonstrated through a concise and highly enantioselective synthesis of (-)-debromoflustramine B. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Synthesis of 1, 4-Dioxan-2-one from 1, 3-Dioxolane and Carbon Monoxide over Cation-exchange Resin Catalyst

    OpenAIRE

    Takagi, Hiroyuki; Oumi, Yasunori; Uozumi, Toshiya; Masuda, Takashi; Sano, Tsuneji

    2001-01-01

    The possibility of the synthesis of 1, 4-dioxan-2-one (p-dioxanon) by carbonylation of 1, 3-dioxolane (cyclic ether) over Nafion® NR-50 cation-exchange resin catalyst was investigated. 1, 4-Dioxan-2-one, one of the cyclic esterethers used as a monomer of polyester, was obtained by depolymerization of polyester oligomers. The maximum yield (40%) of 1, 4-dioxan-2-one was achieved under reaction conditions of 25MPa initial PCO, 120°C reaction temperature and 4h reaction time.

  11. The mild liquid-phase synthesis of 3-picoline from acrolein diethyl acetal and ammonia over heterogeneous catalysts

    Science.gov (United States)

    Luo, Cai-Wu; Chao, Zi-Sheng; Lei, Bo; Wang, Hong; Zhang, Jun; Wang, Zheng-Hao

    2017-11-01

    The liquid-phase synthesis of 3-picoline from the reaction of acrolein diethyl acetal and ammonia over ion-exchanged resins (D402 and D002) and HZSM-5 (Si/Al = 25) was carried out in a batch reactor. Various influencing parameters, including by the addition of water, ion-exchanged resins, reaction temperature and HZSM-5, were systematically investigated. The results showed that the reaction could be directly conducted, and organic acid wasn’t utilized. The highest yield of 3-picoline reached up to 24% using HZSM-5 as catalyst at 110 °C.

  12. The Simple, Effective Synthesis of Highly Dispersed Pd/C and CoPd/C Heterogeneous Catalysts via Charge-Enhanced Dry Impregnation

    Directory of Open Access Journals (Sweden)

    Lawrence D’Souza

    2016-05-01

    Full Text Available Pd/C and CoPd/C heterogeneous catalysts have been synthesized by adopting Charge Enhanced Dry Impregnation (CEDI. The particles size distribution, their high metal surface-to-bulk ratios, and synthesis feasibility are unmatchable to any known noble metal bimetallic heterogeneous catalyst preparation techniques. Next generation Fuel Cells and Fischer-Tropsch catalytic processes economy will be benefited from the proposed methodology.

  13. Development of Ni-Based Catalysts Derived from Hydrotalcite-Like Compounds Precursors for Synthesis Gas Production via Methane or Ethanol Reforming

    OpenAIRE

    Ya-Li Du; Xu Wu; Qiang Cheng; Yan-Li Huang; Wei Huang

    2017-01-01

    As a favorably clean fuel, syngas (synthesis gas) production has been the focus of concern in past decades. Substantial literatures reported the syngas production by various catalytic reforming reactions particularly in methane or ethanol reforming. Among the developed catalysts in these reforming processes, Ni-based catalysts from hydrotalcite-like compounds (HTLcs) precursors have drawn considerable attention for their preferable structural traits. This review covers the recent literature r...

  14. FeRu/TiO2 and Fe/TiO2 catalysts after reduction and Fischer-Tropsch synthesis studied by Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Kraan, A.M. van der; Nonnekens, R.C.H.; Niemantsverdriet, J.W.

    1986-01-01

    A series of TiO 2 -supported bimetallic FeRu catalysts with different Fe:Ru ratios (infinity; 10:1; 3:1; 1:1; 1:3) has been studied by means of in situ Moessbauer spectroscopy. The influence of reduction and Fischer-Tropsch synthesis on the state of iron in the FeRu/TiO 2 catalysts is derived. (Auth.)

  15. Synthesis of DME by CO2 hydrogenation over La2O3-modified CuO-ZnO-ZrO2/HZSM-5 catalysts

    Directory of Open Access Journals (Sweden)

    Zhang Yajing

    2017-01-01

    Full Text Available A series of La2O3-modified CuO-ZnO-ZrO2/HZSM-5 catalysts were prepared by an oxalate co-precipitation method. The catalysts were fully characterized by X-ray diffraction (XRD, N2 adsorption-desorption, hydrogen temperature pro-grammed reduction (H2-TPR, ammonia temperature programmed desorption (NH3-TPD, and X-ray photoelectron spectroscopy (XPS techniques. The effect of the La2O3 content on the structure and performance of the catalysts was thoroughly investigated. The catalysts were evaluated for the direct synthesis of dimethyl ether (DME from CO2 hydrogenation. The results displayed that La2O3 addition enhanced catalytic performance, and the maximal CO2 conversion (34.3% and DME selectivity (57.3% were obtained over the catalyst with 1% La2O3, which due to the smaller size of Cu species and a larger ratio of Cu+/Cu.

  16. Influence of clay type on the performance of Ziegler-Natta catalyst for the synthesis of nanocomposites of PE and PP

    International Nuclear Information System (INIS)

    Almeida, Lidiane A.; Marques, Maria F.V.; Oliveira, Jaqueline S.

    2011-01-01

    Polymer nanocomposites present highly improved general properties in comparison with original polymer and their conventional composites. The mayor disadvantage in preparing these materials is the difficulty in the dispersion of the nanofillers in the polymer matrix. In the present work, the synthesis of bisupported (MgCl 2 /clay) catalyst was performed for obtaining polyethylene and polypropylene nanocomposites by in situ polymerization with the aim to achieve higher dispersion of the nanofillers in the polyolefin matrix. Moreover, the influence of ammonium salt (employed in the organophilization of the clay) on the fixation of the catalyst components and therefore, on the catalyst activity was evaluated. The catalysts were characterized by TGA, SEM, EDX, and XRD. Polymers were characterized by DSC, isotactic index through heptane extractables (HS), TGA, EDX, XRD, and optical microscopy (OM). The results showed that the type of clay modifier has a great influence on the catalyst performance. (author)

  17. Performance of Cobalt-Based Fischer-Tropsch Synthesis Catalysts Using Dielectric-Barrier Discharge Plasma as an Alternative to Thermal Calcination

    International Nuclear Information System (INIS)

    Bai Suli; Huang Chengdu; Lv Jing; Li Zhenhua

    2012-01-01

    Co-based catalysts were prepared by using dielectric-barrier discharge (DBD) plasma as an alternative method to conventional thermal calcination. The characterization results of N 2 -physisorption, temperature programmed reduction (TPR), transmission electron microscope (TEM), and X-ray diffraction (XRD) indicated that the catalysts prepared by DBD plasma had a higher specific surface area, lower reduction temperature, smaller particle size and higher cobalt dispersion as compared to calcined catalysts. The DBD plasma method can prevent the sintering and aggregation of active particles on the support due to the decreased treatment time (0.5 h) at lower temperature compared to the longer thermal calcination at higher temperature (at 500° C for 5 h). As a result, the catalytic performance of the Fischer-Tropsch synthesis on DBD plasma treated Co/SiO 2 catalyst showed an enhanced activity, C 5+ selectivity and catalytic stability as compared to the conventional thermal calcined Co/SiO 2 catalyst.

  18. One-dimensional isothermal multicomponent diffusion-reaction model and its application to methanol synthesis over commercial Cu-based catalyst

    Directory of Open Access Journals (Sweden)

    Lei Kun

    2015-03-01

    Full Text Available The present work was a study on global reaction rate of methanol synthesis. We measured experimentally the global reaction rate in the internal recycle gradientless reactor over catalyst SC309. The diffusion-reaction model of methanol synthesis was suggested. For model we chose the hydrogenation of CO and CO2 as key reaction. CO and CO2 were key components in our model. The internal diffusion effectiveness factors of CO and CO2 in the catalyst were calculated by the numerical integration. A comparison with the experiment showed that all the absolute values of the relative error were less than 10%. The simulation results showed that decreasing reaction temperature and catalyst diameter were conducive to reduce the influence of the internal diffusion on the methanol synthesis.

  19. Survey on synthesis and reaction of environmentally benign water-soluble metal complex catalysts; Kankyo chowagata suiyosei sakutai shokubai no gosei hanno no chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This report describes the research trend survey results on the synthesis and reaction of water-soluble metal complexes which are regarded as environmentally benign catalysts. For the synthesis and catalysis of water-soluble complexes, synthetic methods of water-soluble phosphines, such as sulfonated TPPMS and TPPTS, are described in detail. Synthesis and reactivity of hydroxymethylphosphines are introduced, and the application of electrospray mass spectroscopy is elucidated as a tool for the analysis of them. Changes of the application of transition metal complexes with water-soluble phosphines to catalysis are described. Dual catalysts which have both functions of phase transfer catalysts and homogeneous catalysts are introduced. Concept of counter phase transfer catalysts is also introduced, and some catalytic reactions are described. In addition, this report introduces catalysis of water-soluble polymer-supported metal complexes, immobilization of metal colloids with water-soluble ligands and their analysis, and water-soluble complexes as hybrid catalysts. 144 refs., 94 figs., 10 tabs.

  20. Effect of K promoter on the structure and catalytic behavior of supported iron-based catalysts in fischer-tropsch synthesis

    Directory of Open Access Journals (Sweden)

    F. E. M Farias

    2011-09-01

    Full Text Available Effects of K addition on the performance of supported Fe catalysts for Fischer - Tropsch synthesis (FTS were studied in a slurry reactor at 240 to 270ºC, 2.0 to 4.0 MPa and syngas H2/CO = 1.0. The catalysts were characterized by N2 adsorption, H2 temperature programmed reduction, X - ray diffraction, X - ray fluorescence, thermogravimetric analysis, scanning electron microscopy and dispersive X - ray spectroscopy. A strong interaction was observed between Fe and K, which inhibited the reduction of Fe catalyst. Addition of potassium increased the production of heavy hydrocarbons (C20+.

  1. Comparison of Cobalt based Catalysts Supported on MWCNT and SBA-15 Supporters for Fischer-tropsch Synthesis by Using Novel Vortex Type Reactor

    International Nuclear Information System (INIS)

    Yakubov, A.; Shahrun, M.S.; Kutty, M.G.; Hamid, S.B.A.; Piven, V.

    2011-01-01

    10 and 40 wt% Co/ Multi wall Carbon Nano tubes (MWCNT) and 10 and 40 wt% Co/ Santa Barbara Amorphous-15 (SBA) catalysts were prepared via incipient wetness impregnation and characterized by Scanning Electron Microscopy equipped with Energy Dispersive X-ray Spectroscopy (SEM and EDX), N 2 adsorption-desorption (BET), X-ray Diffractometry (XRD), Transmission Electron Microscopy (TEM) and Temperature- Programmed Reduction and H 2 desorption TPD/RO. Co(NO 3 ) 2 * 6H 2 O was used as a cobalt precursor. 200 ml hastelloy autoclave reactor was implemented to see the performance of the catalysts. This report presents details about the catalyst synthesis and reactor study. (author)

  2. Study on positron annihilation spectroscopy of methanol synthesis catalyst CuO/ZnO

    International Nuclear Information System (INIS)

    Liu Qisheng; Dai Guohuan; Sun Jiying; Ding Yingru; Yao Jianhua

    1989-01-01

    A new method was developed for determining the solid solubility of a metal oxide series prepared by precipitation using the positron lifetime parameters. The positron lifetime spectra of a series of CuO/ZnO catalysts prepared by precipitation were measured, in which the CuO at % contents were different before and after reducing. The relations between the solid solubility of the catalysts and the positron lifetime parameters were obtained, from which a result of solid solubility of 12 CuO at% after reducing had been found. The viewpoint that the Cu + ion acted as the active centre in the CuO/ZnO catalyst was supported

  3. Cascade synthesis of dihydrobenzofuran via Claisen rearrangement of allyl aryl ethers using FeCl3/MCM-41 catalyst

    Directory of Open Access Journals (Sweden)

    Sachin S. Sakate

    2018-05-01

    Full Text Available Dihydrobenzofuran as one of the active ingredients of the naturally occurring motif is synthesized by using in situ generation of ortho allyl phenols. Aryl allyl ethers on reacting with catalytic amounts of non noble metal iron (III chloride supported on MCM-41 under moderate reaction conditions yield dihydrobenzofuran. First step via Claisen rearrangement gives ortho allyl phenol followed by its in situ cyclization to yield dihydrobenzofuran in very good yields. Both Lewis as well as Brønsted acidity of the catalyst as evidenced by Py-FTIR studies was found to catalyze the cascade synthesis of dihydrobenzofuran. The scope of the present strategy was successfully demonstrated for several substrates with varying electronic effects for the synthesis of corresponding dihydrobenzofuran with high yields in a range of 71–86%. Keywords: Claisen rearrangement, Dihydrobenzofuran, Aryl allyl ether, MCM-41, Ferric chloride

  4. Synthesis of carbon nanotubes by CVD method using iron and molybdenum-based catalysts supported on ceramic matrices

    International Nuclear Information System (INIS)

    Teixeira, Ana Paula de Carvalho

    2010-01-01

    Molybdenum is known for its synergistic effect in the synthesis of carbon nanotubes (CNs) by chemical vapor deposition (CVD method). When added to typical catalysts like iron, nickel, and cobalt, even in small quantities, it is increases the yield of these nanostructures. The presence of Mo also has an influence on the type and number of CN walls formed. Although this effect is widely documented in the literature, there is not yet a consensus about the mechanism of action of molybdenum in catalytic systems. The objective of the present work is to study the influence of molybdenum on the catalytic activity of iron nanoparticle-based catalysts supported on magnesium oxide (Fe/MgO system) in the synthesis of carbon nanotubes by the CVD method. The Mo concentration was systematically varied from null to molar ratio values four times greater than the quantity of Fe, and the obtained material (catalysts and carbon nanotubes) were broadly characterized by different techniques. In order to also study the influence of the preparation method on the final composition of the catalytic system phases, the catalytic systems (Fe/MgO e FeMo x /MgO) were synthesized by two different methods: co-precipitation and impregnation. The greatest CN yields were observed for the catalysts prepared by coprecipitation. The difference was attributed to better dispersion of the Fe and Mo phases in the catalyst ceramic matrix. In the precipitation stage, it was observed the formation of layered double hydroxides whose concentration increased with the Mo content up to the ratio of Mo/Fe equal to 0.2. This phase is related to a better distribution of Fe and Mo in this concentration range. Another important characteristic observed is that the ceramic matrix is not inert. It can react both with Fe and Mo and form the iron solid solution in the magnesium oxide and the phases magnesium-ferrite (MgFe 2 0 4 ) and magnesium molybdate (MgMo0 4 ). The MgFe 2 0 4 phase is observed in all catalytic systems

  5. Carbon material@Chitosan composite as catalyst on the synthesis of FAME from used-cooking oil with electrocatalytic process

    Science.gov (United States)

    Syah Putra, Rudy; Antono, Yudi; Pratama, Kharis

    2017-07-01

    The conversion of fatty acid methyl ester (FAME) from soybean oil with a carbon@chitosan composite as alkaline catalyst using electrolysis process had been investigated. The carbon was added onto chitosan through sol-gel method. Carbon material@chitosan, featured with high electrical conductivity and large surface area and Scanning electron microscopy equipped with an energy dispersive spectroscope (EDS) detector was performed to characterize the microstructures as-prepared alcolgels composite. The evaluation of the synthesis process was followed by GC-MS, determining the fatty acid methyl ester (FAME) ratio at different operation variables (e.g oil:MeOH molar ratio at 1:6, THF:MeOH ratio at 1:1 v/v, 10 V and 60 mins). The results showed that the incorporation of carbon resulted in an observable change in the porous structure and an obvious increase in the conductivity strength. When compared with graphite@chitosan composite as catalyst, the carbon@chitosan composite exhibits remarkably FAME yields of 100% in 20 wt.% catalyst loading. The application of those processes was also evaluated when using used-cooking oil as a feedstock of biodiesel production.

  6. Direct Synthesis of Renewable Dodecanol and Dodecane with Methyl Isobutyl Ketone over Dual-Bed Catalyst Systems.

    Science.gov (United States)

    Sheng, Xueru; Li, Ning; Li, Guangyi; Wang, Wentao; Wang, Aiqin; Cong, Yu; Wang, Xiaodong; Zhang, Tao

    2017-03-09

    For the first time, we demonstrated two integrated processes for the direct synthesis of dodecanol or 2,4,8-trimethylnonane (a jet fuel range C 12 -branched alkane) using methyl isobutyl ketone (MIBK) that can be derived from lignocellulose. The reactions were carried out in dual-bed continuous flow reactors. In the first bed, MIBK was selectively converted to a mixture of C 12 alcohol and ketone. Over the Pd-modified magnesium- aluminium hydrotalcite (Pd-MgAl-HT) catalyst, a high total carbon yield (73.0 %) of C 12 oxygenates can be achieved under mild conditions. In the second bed, the C 12 oxygenates generated in the first bed were hydrogenated to dodecanol over a Ru/C catalyst or hydrodeoxygenated to 2,4,8-trimethylnonane over a Cu/SiO 2 catalyst. The as-obtained dodecanol can be used as feedstock in the production of sodium dodecylsulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), which are widely used as surfactants or detergents. The asobtained 2,4,8-trimethylnonane can be blended into conventional jet fuel without hydroisomerization. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Intermetallic compounds of Ni and Ga as catalysts for the synthesis of methanol

    DEFF Research Database (Denmark)

    Sharafutdinov, Irek; Elkjær, Christian Fink; de Carvalho, Hudson Wallace Pereira

    2014-01-01

    In this work, we present a detailed study of the formation of supported intermetallic Ni–Ga catalysts for CO2 hydrogenation to methanol. The bimetallic phase is formed during a temperature-programmed reduction of the metal nitrates. By utilizing a combination of characterization techniques......, in particular in situ and ex situ X-ray diffraction, in situ X-ray absorption spectroscopy, transmission electron microscopy combined with electron energy loss spectroscopy and X-ray fluorescence, we have studied the formation of intermetallic Ni–Ga catalysts of two compositions: NiGa and Ni5Ga3. These methods...... demonstrate that the catalysts with the desired intermetallic phase and composition are formed upon reduction in hydrogen and enable us to propose a mechanism of the Ni–Ga nanoparticles formation. By studying the effect of calcination prior to catalyst reduction, we show that the reactivity depends...

  8. Synthesis of cerium oxide catalysts supported on MCM-41 molecular sieve

    International Nuclear Information System (INIS)

    Souza, E.L.S.; Barros, T.R.B.; Sousa, B.V. de

    2016-01-01

    Porous materials have been widely studied as catalysts and catalyst support. The MCM-41 structure is the one that has been most studied because of its application possibilities in chemical processes. This work aimed to obtain and characterize cerium oxide catalysts supported on MCM-41 molecular sieve. The molecular sieve was synthesized by the conventional method with the following molar composition: 1 SiO2: 0.30 CTABr: NH3 11: 144 H2O. Then, 25% w/w cerium was incorporated into the MCM-41 using the wet impregnation process and the material obtained was activated by calcination. From the XRD patterns was confirmed the structure of the molecular sieve, and were identified the cerium oxide phases in its structure. The textural catalysts characteristics were investigated by isotherms of N2 adsorption/desorption (BET method). (author)

  9. Nano indium oxide as a recyclable catalyst for the synthesis of ...

    Indian Academy of Sciences (India)

    yields, simple methodology, short reaction times and easy work-up. The catalyst can be ... In recent years there has been a tremendous interest in various chemical ..... Branch for partial financial support to carry out this research work.

  10. Thiamine hydrochloride: An efficient catalyst for one-pot synthesis of ...

    Indian Academy of Sciences (India)

    thiamine hydrochloride (VB1) as an inexpensive, non-toxic and metal ion free catalyst at ambient temperature. Keywords. ... from practical applications due to environmental and economic ... filtered and purified by column chromatography on.

  11. A facile approach for the synthesis of porous KTiNbO5 catalyst with ...

    Indian Academy of Sciences (India)

    2018-04-06

    Apr 6, 2018 ... School of Chemical Engineering, Anhui University of Science and Technology, Huainan, Anhui 232001, ... HTiNbO5, is widely used as a catalyst in organic reac- ... synthesized using a facile method and applied in the hydro-.

  12. Catalytic Activity of Sulfated and Phosphated Catalysts towards the Synthesis of Substituted Coumarin

    Directory of Open Access Journals (Sweden)

    Nagi R. E. Radwan

    2018-01-01

    Full Text Available New modified acidic catalysts were prepared from the treatment of silica, titania and silica prepared from hydrolyzed tetraethyl orthosilicate (TEOS with sulfuric and phosphoric acid. The sulfated and phosphated silica synthesized from TEOS were calcined at 450 and 650 °C. These catalysts were characterized by X-ray diffraction (XRD, Fourier-transform infrared spectroscopy (FTIR, transmission electron microscope (TEM, and scanning electron microscope (SEM. The surface areas, total pore volume, and mean pore radius of the acidic catalysts were investigated, while the pore size distribution was determined by the Barrett, Joyner and Halenda (BJH method. The catalytic activity of the sulfated and phosphated silica and/or titania were examined with the Pechmann condensation reaction, in which different phenols reacted with ethyl acetoacetate as a neat reaction to obtain the corresponding coumarin derivatives. The results indicated that the treatment of the catalysts with sulfuric or phosphoric acid led to a decrease in the phases’ crystallinity to a certain degree. The morphology and the structure of the acidified catalysts were examined and their particle size was calculated. Furthermore, the amount of the used catalysts played a vital role in controlling the formation of the products as well as their performance was manipulated by the number and nature of the active acidic sites on their surfaces. The obtained results suggested that the highest catalytic conversion of the reaction was attained at 20 wt % of the catalyst and no further increase in the product yield was detected when the amount of catalyst exceeded this value. Meanwhile the phenol molecules were a key feature in obtaining the final product.

  13. Active Heterogeneous CaO Catalyst Synthesis from Anadara granosa (Kerang Seashells for Jatropha Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Reddy ANR

    2017-01-01

    Full Text Available Heterogeneous catalysts are often used at large to produce biodiesel from non-edible vegetable crude oils such as Jatropha curcas oil (JCO. In this study, an active heterogeneous CaO catalyst was synthesized from a tropical biodiversity seashells Anadara granosa (A.granosa. The catalytic efficiency of A.granosa CaO was investigated in transesterification of JCO as biodiesel. The A.granosa CaO catalyst was synthesized using ‘Calcination – hydration – dehydration’ protocol. The spectral characterization of the catalyst were investigated by employing FT-IR, SEM, BET and BJH spectrographic techniques. The experimental design was executed with four reaction parameters that include catalyst concentration (CC, methanol ratio (MR, transesterification time (TT and reaction temperature (RT. The JCO transesterification reactions as well as impact of reaction parameters on the Jatropha biodiesel yield (JBY were analyzed. The sufficiency of the experimental results conformed through sequential validation tests, as a result, an average of 96.2% JMY was noted at optimal parametric conditions, CC of 3wt. %, TT of 120 min, MR of 5 mol. and RT of 60ºC at a constant agitation speed of 300rpm. An average JMY of 87.6% was resulted from the A.granosa CaO catalyst during their recycling and reuse studies up to third reuse cycle.

  14. Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

    Directory of Open Access Journals (Sweden)

    Galip Akay

    2016-05-01

    Full Text Available A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state can be controlled from a few seconds to several minutes. The resulting nano-structured micro-porous silica supported catalyst system has a surface area approaching 300 m2/g and X-ray Diffraction (XRD-based catalyst size controlled in the range of 1–10 nm in which the catalyst structure appears as lamellar sheets sandwiched between the catalyst support. These catalyst characteristics are dependent primarily on the processing history as well as the catalyst (Fe, Co and Ni studied when the catalyst/support molar ratio is typically 0.1–2. In addition, Ca, Mn and Cu were used as co-catalysts with Fe and Co in the evaluation of the mechanism of catalyst generation. Based on extensive XRD, Scanning Electron Microscopy (SEM and Transmission Electron Microscopy (TEM studies, the micro- and nano-structure of the catalyst system were evaluated. It was found that the catalyst and silica support form extensive 0.6–2 nm thick lamellar sheets of 10–100 nm planar dimensions. In these lamellae, the alternate silica support and catalyst layer appear in the form of a bar-code structure. When these lamellae structures pack, they form the walls of a micro-porous catalyst system which typically has a density of 0.2 g/cm3. A tentative mechanism of catalyst nano-structure formation is provided based on the rheology and fluid mechanics of the catalyst/support precursor fluid as well as co-assembly nano-reactor formation during processing. In order to achieve these structures and characteristics, catalyst support must be in the form of silane coated silica nano

  15. Cavitation assisted synthesis of fatty acid methyl esters from sustainable feedstock in presence of heterogeneous catalyst using two step process.

    Science.gov (United States)

    Dubey, Sumit M; Gole, Vitthal L; Gogate, Parag R

    2015-03-01

    The present work reports the intensification aspects for the synthesis of fatty acid methyl esters (FAME) from a non-edible high acid value Nagchampa oil (31 mg of KOH/g of oil) using two stage acid esterification (catalyzed by H₂SO₄) followed by transesterification in the presence of heterogeneous catalyst (CaO). Intensification aspects of both stages have been investigated using sonochemical reactors and the obtained degree of intensification has been established by comparison with the conventional approach based on mechanical agitation. It has been observed that reaction temperature for esterification reduced from 65 to 40 °C for the ultrasonic approach whereas there was a significant reduction in the optimum reaction time for transesterification from 4h for the conventional approach to 2.5h for the ultrasound assisted approach. Also the reaction temperature reduced marginally from 65 to 60 °C and yield increased from 76% to 79% for the ultrasound assisted approach. Energy requirement and activation energy for both esterification and transesterification was lower for the ultrasound based approach as compared to the conventional approach. The present work has clearly established the intensification obtained due to the use of ultrasound and also illustrated the two step approach for the synthesis of FAME from high acid value feedstock based on the use of heterogeneous catalyst for the transesterification step. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. The Effect of Time dealumination and Solvent Concentration in Synthesis of Zeolite Catalyst and Catalytic Test for DiEthyl Ether Production Process

    International Nuclear Information System (INIS)

    Widayat; Roesyadi, A.; Rachimoellah, M.

    2009-01-01

    Ethanol is an alternative energy, but its has three distinct disadvantages as a transportation fuel. Its availability is currently limited, and it has a lower volumetric heating value and a lower Reid vapour pressure (RVP) than gasoline. This paper focuses for this disadvantages and to solve this problem can do with converts ethanol to DiEthyl Ether product. This research produced DiEthyl Ether by ethanol dehydration process with zeolite as catalyst. The catalyst synthesis from natural material from District Gunung Kidul, Indonesia. The catalyst produced with dealumination, neutralization, drying and calcination processes. The zeolite catalyst was analysed of Si/Al, X-ray Diffraction and specific surface area. The catalyst product then used for ethanol dehydration to produce DiEthyl Ether. The results shown the biggest surface area is 184,52 m 2 /gram at catalyst production at 10 hours for time dealumination. The crystallite of catalyst product is similar like shown at diffractogram of XRD analysis. The ratio Si/Al biggest is 313.7 that obtaining at catalyst production with 7 hours for time dealumination. The catalytic test use fixed bed reactor with 1 inci diameter and ethanol fermentation both as feed. The operation condition is 150 deg. C at temperature and atmosphere pressure. The compounds product in liquid phase are diethyl ether, methanol and water.

  17. Commercial- and whitewashing-grade limestone as a heterogeneous catalyst for synthesis of fatty acid methyl esters from used frying oil (UFO)

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Shweta; Singh, Bhaskar; Sharma, Yogesh C. [Banaras Hindu University, Department of Applied Chemistry, Institute of Technology, Varanasi (India); Frometa, Amado Enrique N. [Universidad Tecnologica de Izucar de Matamoros, Puebla (Mexico)

    2012-12-15

    Commercial-grade limestone used in whitewashing which is a low-cost material has been used as a catalyst for the synthesis of fatty acid methyl esters. The catalyst was characterized by differential thermal analysis/thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy for the study of its physicochemical nature. The catalyst was calcined at 900 C for 2.5 h for the decomposition of calcium carbonate to calcium oxide. The catalyst was further activated by dissolving 1.5 wt% of catalyst in 30 ml methanol (7.5:1, methanol to used frying oil molar ratio) and stirred at 25 C for 1 h on a magnetic stirrer. The transesterification reaction was performed using calcium oxide as a catalyst and then with the ''activated calcium oxide.'' The conversion obtained was 94.4 % with calcium oxide and was found to be lower for the ''activated calcium oxide'' (i.e., 87.36 %). The conversion increased to 96.8 % on increasing the catalyst amount to 2.0 wt% in 5 h. A high yield (>95 %) of fatty acid methyl esters was observed when either calcium oxide or ''activated calcium oxide'' was taken as catalyst. The catalytic activity of calcium oxide obtained from low-grade limestone has been found to be comparable with the laboratory-grade CaO. (orig.)

  18. Impact of Contaminants Present in Coal-Biomass Derived Synthesis Gas on Water-gas Shift and Fischer-Tropsch Synthesis Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Alptekin, Gokhan [TDA Research, Inc., Wheat Ridge, CO (United States)

    2013-02-15

    Co-gasification of biomass and coal in large-scale, Integrated Gasification Combined Cycle (IGCC) plants increases the efficiency and reduces the environmental impact of making synthesis gas ("syngas") that can be used in Coal-Biomass-to-Liquids (CBTL) processes for producing transportation fuels. However, the water-gas shift (WGS) and Fischer-Tropsch synthesis (FTS) catalysts used in these processes may be poisoned by multiple contaminants found in coal-biomass derived syngas; sulfur species, trace toxic metals, halides, nitrogen species, the vapors of alkali metals and their salts (e.g., KCl and NaCl), ammonia, and phosphorous. Thus, it is essential to develop a fundamental understanding of poisoning/inhibition mechanisms before investing in the development of any costly mitigation technologies. We therefore investigated the impact of potential contaminants (H2S, NH3, HCN, AsH3, PH3, HCl, NaCl, KCl, AS3, NH4NO3, NH4OH, KNO3, HBr, HF, and HNO3) on the performance and lifetime of commercially available and generic (prepared in-house) WGS and FT catalysts.

  19. Mixed phase Pt-Ru catalyst for direct methanol fuel cell anode by flame aerosol synthesis

    DEFF Research Database (Denmark)

    Chakraborty, Debasish; Bischoff, H.; Chorkendorff, Ib

    2005-01-01

    A spray-flame aerosol catalyzation technique was studied for producing Pt-Ru anode electrodes for the direct methanol fuel cell. Catalysts were produced as aerosol nanoparticles in a spray-flame reactor and deposited directly as a thin layer on the gas diffusion layer. The as-prepared catalyst wa......Ru1/Vulcan carbon. The kinetics of methanol oxidation on the mixed phase catalyst was also explored by electrochemical impedance spectroscopy. (c) 2005 The Electrochemical Society.......A spray-flame aerosol catalyzation technique was studied for producing Pt-Ru anode electrodes for the direct methanol fuel cell. Catalysts were produced as aerosol nanoparticles in a spray-flame reactor and deposited directly as a thin layer on the gas diffusion layer. The as-prepared catalyst...... was found to be a mixture of nanocrystalline, mostly unalloyed Pt and an amorphous phase mostly of Ru and to a lesser extent of Pt oxides on top of the crystalline phase. The flame-produced Pt1Ru1 demonstrated similar onset potential but similar to 60% higher activity compared to commercially available Pt1...

  20. Bio diesel synthesis from pongamia pinnata oil over modified CeO2 catalysts

    International Nuclear Information System (INIS)

    Venkatesh; Sathgatta Z, M. S.; Manjunatha, S.; Thammannigowda V, V.

    2014-01-01

    This study investigates the use of CeO 2 , ZrO 2 , Mg O and CeO 2 -ZrO 2 , CeO 2 -Mg O, CeO 2 -ZrO 2 -Mg O mixed oxides as solid base catalysts for the transesterification of Pongamia pinnata oil with methanol to produce bio diesel. SO 4 2- /CeO 2 and SO 4 2- /CeO 2 -ZrO 2 were also prepared and used as solid acid catalysts for esterification of Pongamia pinnata oil (P-oil) to reduce the % of free fatty acid (FFA) in P-oil. The oxide catalysts were prepared by an incipient wetness impregnation method and characterized by techniques such as NH 3 -Tpd for surface acidity, CO 2 -Tpd for surface basicity and powder X-ray diffraction for crystallinity. The effect of nature of the catalyst, methanol to P-oil molar ratio and reaction time in esterification as well as in transesterification was investigated. The catalytic materials were reactive d and reused for five reaction cycles and the results showed that the ceria based catalysts have reasonably good reusability both in esterification and transesterification reaction. The test results also revealed that the CeO 2 -ZrO 2 modified with Mg O could have potential for use in the large scale bio diesel production. (Author)

  1. Synthesis of biodiesel from pongamia oil using heterogeneous ion-exchange resin catalyst.

    Science.gov (United States)

    Jaya, N; Selvan, B Karpanai; Vennison, S John

    2015-11-01

    Biodiesel is a clean-burning renewable substitute fuel for petroleum. Biodiesel could be effectively produced by transesterification reaction of triglycerides of vegetable oils with short-chain alcohols in the presence of homogeneous or heterogeneous catalysts. Conventionally, biodiesel manufacturing processes employ strong acids or bases as catalysts. But, separation of the catalyst and the by-product glycerol from the product ester is too expensive to justify the product use as an automobile fuel. Hence heterogeneous catalysts are preferred. In this study, transesterification of pongamia oil with ethanol was performed using a solid ion-exchange resin catalyst. It is a macro porous strongly basic anion exchange resin. The process parameters affecting the ethyl ester yield were investigated. The reaction conditions were optimized for the maximum yield of fatty acid ethyl ester (FAEE) of pongamia oil. The properties of FAEE were compared with accepted standards of biodiesel. Engine performance was also studied with pongamia oil diesel blend and engine emission characteristics were observed. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Controllable synthesis of Co3O4 nanocrystals as efficient catalysts for oxygen reduction reaction

    Science.gov (United States)

    Li, Baoying; Zhang, Yihe; Du, Ruifeng; Liu, Lei; Yu, Xuelian

    2018-03-01

    The electrochemical oxygen reduction reaction (ORR) has received great attention due to its importance in fuel cells and metal-air batteries. Here, we present a simple approach to prepare non-noble metal catalyst-Co3O4 nanocrystals (NCs). The particle size and shape were simply controlled by different types and concentrations of metal precursor. Furthermore, different sizes and shapes of Co3O4 NCs are explored as electrocatalysts for ORR, and it has been observed that particles with a similar shape, and smaller particle size led to greater catalytic current densities because of the greater surface area. For particles with a comparable size, the shape or crystalline structure governed the activity of the electrocatalytic reactions. Most importantly, the 9 nm-Co3O4 were demonstrated to act as low-cost catalysts for the ORR with a similar performance to that of Pt catalysts.

  3. Synthesis of Biodiesel in Batch and Packed-Bed Reactors Using Powdered and Granular Sugar Catalyst

    Science.gov (United States)

    Janaun, J.; Lim, P. M.; Balan, W. S.; Yaser, A. Z.; Chong, K. P.

    2017-06-01

    Increasing world production of palm oil warrants effective utilization of its waste. In particular, conversion of waste cooking oil into biodiesel has obtained global interest because of renewable energy need and reduction of CO2 emission. In this study, oleic acid used as a model compound for waste cooking oil conversion using esterification reaction catalysed by sugar catalyst (SC) in powdered (P-SC) and granular (G-SC) forms. The catalysts were synthesized via incomplete carbonization of D-glucose followed by functionalization with concentrated sulphuric acid. Catalysts characterizations were done for their physical and chemical properties using modern tools. Batch and packed-bed reactor systems were used to evaluate the reactivity of the catalysts. The results showed that G-SC had slightly higher total acidity and more porous than P-SC. The experimental conditions for batch reaction were temperature of 60°C, molar ratio of 1:20 (Oleic Acid:Methanol) and 2 wt. catalyst with respect to oleic acid. The results showed the maximum oleic acid conversion using G-SC and P-SC were 52 and 48, respectively. Whereas, the continuous reaction with varying feed flow rate as a function of retention time was studied by using 3 g of P-SC in 60 °C and 1:20 molar ratio in a packed-bed reactor. The results showed that a longer retention time which was 6.48 min and feed flow rate 1.38 ml/min, achieved higher average conversion of 9.9 and decreased with further increasing flow rate. G-SC showed a better average conversion of 10.8 at lowest feed flow rate of 1.38 ml/min in continuous reaction experiments. In a broader perspective, large scale continuous biodiesel production is feasible using granular over powdered catalyst mainly due to it lower pressure drop.

  4. New fillers in the synthesis of polypropylene nano composites with Ziegler-Natta catalysts

    International Nuclear Information System (INIS)

    Rosa, Jeferson L.S.; Silva, Marcelo C.V.; Marques, Maria F.V.

    2011-01-01

    In this study, Ziegler-Natta catalysts bi-supported on MgCl 2 and natural clays were prepared in order to synthesize polypropylene nanocomposites. The employed clays were bentonite, as reference, as well as halloysite, vermiculite and mica. Propylene polymerizations were carried out using those catalysts and the properties of the obtained materials were analyzed using techniques of thermogravimetric analysis X-ray diffraction, dynamic mechanical thermal analysis e scanning electronic microscopy. Results showed the production of nanocomposites with higher thermal degradation temperature. (author)

  5. Influence of Multi-Valency, Electrostatics and Molecular Recognition on the Adsorption of Transition Metal Complexes on Metal Oxides: A Molecular Approach to Catalyst Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Rioux, Robert M. [Pennsylvania State Univ., University Park, PA (United States)

    2017-03-31

    In this work, we have primarily utilized isothermal titration calorimetry (ITC) and complimentary catalyst characterization techniques to study and assess the impact of solution conditions (i.e., solid-liquid) interface on the synthesis of heterogeneous and electro-catalysts. Isothermal titration calorimetry is well-known technique from biochemistry/physics, but has been applied to a far lesser extent to characterize buried solid-liquid interfaces in materials science. We demonstrate the utility and unique information provided by ITC for two distinct catalytic systems. We explored the thermodynamics associated catalyst synthesis for two systems: (i) ion-exchange or strong electrostatic adsorption for Pt and Pd salts on silica and alumina materials (ii) adsorption to provide covalent attachment of metal and metal-oxo clusters to Dion-Jacobsen perovskite materials.

  6. Recent progress in synthesis and surface functionalization of mesoporous acidic heterogeneous catalysts for esterification of free fatty acid feedstocks: A review

    International Nuclear Information System (INIS)

    Soltani, Soroush; Rashid, Umer; Al-Resayes, Saud Ibrahim; Nehdi, Imededdine Arbi

    2017-01-01

    Highlights: • Mesoporous catalysts have potential to esterify the wastes feedstocks. • Surface area of mesoporous catalysts depends on materials synthesis methods. • Hydrophobic surface of sulfonated catalyst causes adsorption on FFA particles. • Mesoporous catalysts have large active sites to trap free fatty acids particles. • Recyclability of mesoporous catalyst is a key feature for biodiesel production. - Abstract: Biodiesel is considered as a sulfur free, non-toxic and biodegradable source of energy and its burning provide less pollution than petroleum based fuels. In case of using fried waste oils, animal’s fats and waste cultivated oil which contain high free fatty acid (FFA), esterification is taking place. Through esterification reaction, catalyst is an integral part which accelerates the FFA conversion to the methyl ester (ME) in shorter reaction time. Although, most of the current catalysts have some defect such as poor recyclability, less surface area and poor porosity. Mesoporous materials have been recently attracted remarkable interests because of its desirable properties, such as large and harmonized surface area, tuneable mesoporous channels with flexible pore size, excellent thermal stability, and post-functionalization surface characteristics. The combination of remarkable physico-chemical and textural properties as well as high activity has proposed them as advanced materials. In this review, it has been attempted to present the details of fundamental properties of mesoporous catalysts, various synthetic methods and formation mechanisms, and surface functionalization methodologies. The effects of various factors (such as surface area, porosity, acidity, post-calcination temperature, and reaction parameters) on esterification of different feedstocks are discussed in detail. Furthermore, the kinetic study of esterification reaction in the presence of mesoporous catalysts is also elaborated. At the end, remarkable challenges and outlooks

  7. Continuous-flow hydration–condensation reaction: Synthesis of α,β-unsaturated ketones from alkynes and aldehydes by using a heterogeneous solid acid catalyst

    Directory of Open Access Journals (Sweden)

    Magnus Rueping

    2011-12-01

    Full Text Available A simple, practical and efficient continuous-flow hydration–condensation protocol was developed for the synthesis of α,β-unsaturated ketones starting from alkynes and aldehydes by employing a heterogeneous catalyst in a flow microwave. The procedure presents a straightforward and convenient access to valuable differently substituted chalcones and can be applied on multigram scale.

  8. Highly Efficient Catalytic Synthesis of α-Amino Acids under Phase-Transfer Conditions with a Novel Catalyst/Substrate Pair

    NARCIS (Netherlands)

    Belokon, Yuri N.; Kochetkov, Konstantin A.; Churkina, Tatiana D.; Ikonnikov, Nikolai S.; Larionov, Oleg V.; Harutyunyan, Syuzanna R.; Vyskočil, Štepán; North, Michael; Kagan, Henri B.

    2001-01-01

    A facile and fast enantioselective synthesis of α-amino acids with high ee values was achieved by the asymmetric alkylation of the glycine derivative under phase-transfer conditions with (R)- or (S)-2-amino-2'-hydroxy-1,1'-binaphthyl (NOBIN). The ee value of the catalyst can be as little as 40 %

  9. CATALYST-FREE REACTIONS UNDER SOLVENT-FEE CONDITIONS: MICROWAVE-ASSISTED SYNTHESIS OF HETEROCYCLIC HYDRAZONES BELOW THE MELTING POINT OF NEAT REACTANTS: JOURNAL ARTICLE

    Science.gov (United States)

    NRMRL-CIN-1437 Jeselnik, M., Varma*, R.S., Polanc, S., and Kocevar, M. Catalyst-free Reactions under Solvent-fee Conditions: Microwave-assisted Synthesis of Heterocyclic Hydrazones below the Melting Point of Neat Reactants. Published in: Chemical Communications 18:1716-1717 (200...

  10. An Undergraduate Chemistry Laboratory: Synthesis of Well-Defined Polymers by Low-Catalyst-Concentration ATRP and Postpolymerization Modification to Fluorescent Materials

    Science.gov (United States)

    Tsarevsky, Nicolay V.; Woodruf, Shannon R.; Wisian-Neilson, Patty J.

    2016-01-01

    A two-session experiment is designed to introduce undergraduate students to concepts in catalysis, transition metal complexes, polymer synthesis, and postpolymerization modifications. In the first session, students synthesize poly(glycidyl methacrylate) via low-catalyst-concentration atom transfer radical polymerization (ATRP). The…

  11. Synthesis, characterization and testing of a new V2O5/Al2O3−MgO catalyst for butane dehydrogenation and limonene oxidation

    NARCIS (Netherlands)

    Strassberger, Z.; Ramos-Fernandez, E.V.; Boonstra, A.; Jorna, R.; Tanase, S.; Rothenberg, G.

    2013-01-01

    We report the synthesis and characterization of new V2O5/Al2O3-MgO catalysts and their application in oxidative dehydrogenation and epoxidation reactions. The materials were prepared by wet impregnation under excess acid conditions. Anchoring of the desired species on the support occurs via an

  12. Synthesis of 1,2-Disubstituted Benzimidazoles in the Presence of SBA-Pr-SO3H as a Nano Solid Acid Catalyst

    Directory of Open Access Journals (Sweden)

    G. Mohammadi Ziarani

    2012-06-01

    Full Text Available In this article, simple, convenient synthesis of 2-aryl-1- arylmethyl-1H-1,3-benzimidazole (1,2-disubstituted benzimidazoles via condensation of 1,2-phenylenediamine and aromatic aldehydes using SBA-Pr-SO3H as a nanoporous solid acid catalyst in green protocol was reported.

  13. Synthesis and characterization of triflic acid-functionalized mesoporous Zr-TMS catalysts: heterogenization of CF3SO3H over Zr-TMS and its catalytic activity

    NARCIS (Netherlands)

    Chidambaram, M.; Curulla Ferre, D.; Singh, A.P.; Anderson, B.G.

    2003-01-01

    Triflic acid-functionalized Zr-TMS (zirconium oxide with a mesostructured framework; TMS, transition metal oxide mesoporous molecular sieves) catalysts have been synthesized by functionalizing triflic acid onto the walls of Zr-TMS via post synthesis method. The synthesized materials were

  14. OSU-6: A Highly Efficient, Metal-Free, Heterogeneous Catalyst for the Click Synthesis of 5-Benzyl and 5-Aryl-1H-tetrazoles

    Directory of Open Access Journals (Sweden)

    Baskar Nammalwar

    2015-12-01

    Full Text Available OSU-6, an MCM-41 type hexagonal mesoporous silica with mild Brönsted acid properties, has been used as an efficient, metal-free, heterogeneous catalyst for the click synthesis of 5-benzyl and 5-aryl-1H-tetrazoles from nitriles in DMF at 90 °C. This catalyst offers advantages including ease of operation, milder conditions, high yields, and reusability. Studies are presented that demonstrate the robust nature of the catalyst under the optimized reaction conditions. OSU-6 promotes the 1,3-dipolar addition of azides to nitriles without significant degradation or clogging of the nanoporous structure. The catalyst can be reused up to five times without a significant reduction in yield, and it does not require treatment with acid between reactions.

  15. Synthesis and characterization of Fe–Ni/ɣ-Al2O3 egg-shell catalyst for H2 generation by ammonia decomposition

    DEFF Research Database (Denmark)

    Silva, Hugo José Lopes; Nielsen, Morten Godtfred; Fiordaliso, Elisabetta Maria

    2015-01-01

    The Fe–Ni alloyed nanoparticles are a promising alternative to expensive ruthenium-based catalysts for a real-scale application of hydrogen generation by ammonia decomposition. In practical applications, millimeter-sized extrudates are used as catalyst supports, where the spatial distribution...... of the active phase should match with the type of reaction. In this work, a novel synthesis route was developed for the preparation of a Fe–Ni/ɣ-Al2O3 egg-shell catalyst. Egg-shell is a preferred profile considering the highly endothermic nature of ammonia decomposition reaction. The high viscosity of glycerol...... using focused ion bean (FIB) milling allowed to acquire high resolution images of the Ni and Fe nanoparticles on ɣ-Al2O3, which is particularly challenging due to the crystalline nature of this support. Distinct regions of the egg-shell catalyst were analyzed through scanning TEM (STEM) and TEM...

  16. An economically viable synthesis of biodiesel from a crude Millettia pinnata oil of Jharkhand, India as feedstock and crab shell derived catalyst.

    Science.gov (United States)

    Madhu, Devarapaga; Chavan, Supriya B; Singh, Veena; Singh, Bhaskar; Sharma, Yogesh C

    2016-08-01

    Biodiesel has emerged as a prominent source to replace petroleum diesel. The cost incurred in the production of biodiesel is higher than that for refining of crude oil to obtain mineral diesel. The heterogeneous catalyst was prepared from crab shells by calcining the crushed mass at 800°C. The solid waste catalyst was characterized with XRD, XPS, BET, SEM-EDS, and FT-IR. Millettia pinnata (karanja) oil extracted from its seeds was used as a feedstock for the synthesis of biodiesel. Biodiesel was synthesized through esterification followed by transesterification in a two-step process. Characterization of biodiesel was done using proton NMR spectroscopy. Reaction parameters such as reaction time, reaction temperature, concentration of catalyst and stirrer speed were optimized. Reusability of catalyst was checked and found that there was no loss of catalytic activity up to five times. Copyright © 2016. Published by Elsevier Ltd.

  17. Heterometallic metal-organic framework-templated synthesis of porous Co3O4/ZnO nanocage catalysts for the carbonylation of glycerol

    Science.gov (United States)

    Lü, Yinyun; Jiang, Yating; Zhou, Qi; Li, Yunmei; Chen, Luning; Kuang, Qin; Xie, Zhaoxiong; Zheng, Lansun

    2017-12-01

    The efficient synthesis of glycerol carbonate (GLC) has recently received great attention due to its significance in reducing excess glycerol in biodiesel production as well as its promising applications in several industrial fields. However, the achievement of high conversion and high selectivity of GLC from glycerol in heterogeneous catalytic processes remains a challenge due to the absence of high-performance solid catalysts. Herein, highly porous nanocage catalysts composed of well-mixed Co3O4 and ZnO nanocrystals were successfully fabricated via a facile heterometallic metal-organic framework (MOF)-templated synthetic route. Benefiting from a high porosity and the synergistic effect between Co3O4 and ZnO, the as-prepared composite catalysts exhibited a significantly enhanced production efficiency of GLC in the carbonylation reaction of glycerol with urea compared to the single-component counterparts. The yield of GLC over the Co50Zn50-350 catalyst reached 85.2%, with 93.3% conversion and near 91% GLC selectivity, and this catalytic performance was superior to that over most heterogeneous catalysts. More importantly, the proposed templated synthetic strategy of heterometallic MOFs facilitates the regulation of catalyst composition and surface structure and can therefore be potentially extended in the tailoring of other metal oxide composite catalysts.

  18. Relations Between Morphology and Catalytic Activity of Ion Exchanger Catalysts for Synthesis of Bisphenol A

    Czech Academy of Sciences Publication Activity Database

    Jeřábek, Karel; Hanková, Libuše; Prokop, Zdeněk; Lundquist, E. G.

    2002-01-01

    Roč. 232, 1-2 (2002), s. 181-188 ISSN 0926-860X R&D Projects: GA ČR GA104/99/0125 Keywords : ion exchangers * catalyst * morphology Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.915, year: 2002

  19. Synthesis of cracked Calophyllum inophyllum oil using fly ash catalyst for diesel engine application

    KAUST Repository

    Muthukumaran, N.

    2015-04-16

    In this study, production of hydrocarbon fuel from Calophyllum inophyllum oil has been characterized for diesel engine application, by appraising essential fuel processing parameters. As opposed to traditional trans-esterification process, the reported oil was cracked using a catalyst, as the latter improves the fuel properties better than the former. In a bid to make the production process economically viable, a waste and cheap catalyst, RFA (raw fly ash), has been capitalized for the cracking process as against the conventional zeolite catalyst. The fuel production process, which is performed in a fixed bed catalytic reactor, was done methodologically after comprehensively studying the characteristics of fly ash catalyst. Significantly, fly ash characterization was realized using SEM and EDS, which demarcated the surface and internal structures of fly ash particles before and after cracking. After the production of hydrocarbon fuel from C. inophyllum oil, the performed compositional analysis in GC-MS revealed the presence of esters, parfins and olefins. Followed by the characterization of catalytically cracked C. inophyllum oil, suitable blends of it with diesel were tested in a single cylinder diesel engine. From the engine experimental results, BTE (brake thermal efficiency) of the engine for B25 (25% cracked C. inophyllum oil and 75% diesel) was observed to be closer to diesel, while it decreased for higher blends. On the other hand, emissions such as HC (hydrocarbon), CO (carbon monoxide) and smoke were found to be comparable for B25 with diesel. © 2015 Elsevier Ltd. All rights reserved.

  20. Hairy foam: carbon nanofibers on solid foam as catalyst support : synthesis, mass transfer, and reactor modeling

    NARCIS (Netherlands)

    Wenmakers, P.W.A.M.

    2010-01-01

    The chemical reactor is at the heart of many chemical processes. The chemical industry strives for the most efficient, most compact, and safest chemical reactor. The efficiency of a chemical reactor is determined by the delicate balance of catalyst performance (i.e. selectivity and activity) and the

  1. Controllable synthesis of SnO2 nanowires and nanobelts by Ga catalysts

    International Nuclear Information System (INIS)

    Xie Xing; Shao Zhibin; Yang Qianhui; Shen Xiaoshuang; Zhu Wei; Hong Xun; Wang Guanzhong

    2012-01-01

    We report the morphology control of one-dimensional (1D) SnO 2 nanostructures by Ga catalysts using thermal evaporation method. Gallium (Ga), either from decomposition of GaN powder or from Ga metal, is adopted as a catalyst for the growth of long SnO 2 nanowires and nanobelts. At similar experimental conditions, quantities of nanobelts are formed instead of nanowires when the temperature and reaction time are increased. Such approach enables us to synthesize various morphologies of SnO 2 nanobelts with different side facets. Novel nanobelts with [0 0 1] growth direction with high energy side facets are obtained for the first time, which is attributed to the large amount of oxygen vacancies introduced in the nanobelts by the Ga catalysts. - Graphical abstract: Morphology control of one-dimensional SnO 2 nanostructures are realized via a thermal evaporation method. Novel nanobelts along [0 0 1] direction having high energy side facets were fabricated for the first time. Highlights: ► Morphology control of one-dimensional SnO 2 nanostructures are realized by Ga catalysts using thermal evaporation method. ► Oxygen vacancies influenced the growth directions in order to neutralize thermodynamic instability. ► Novel nanobelts with [0 0 1] growth direction with high energy side facets are obtained for the first time.

  2. Cu-MCM-41 nanoparticles: An efficient catalyst for the synthesis of 5 ...

    Indian Academy of Sciences (India)

    To investigate reusability, the catalyst was recovered by simple filtration and reused for several cycles with consistent activity. Keywords. ... membranes. Another advantage of tetrazolic acids over carboxylic acids is that they are resistant to many bio- logical metabolic degradation pathways.3. Conventionally 5-substituted ...

  3. The renaissance of iron-based Fischer–Tropsch synthesis: on the multifaceted catalyst deactivation behaviour

    NARCIS (Netherlands)

    de Smit, E.|info:eu-repo/dai/nl/304824232; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397

    2008-01-01

    Iron-based Fischer–Tropsch catalysts, which are applied in the conversion of CO and H2 into longer hydrocarbon chains, are historically amongst the most intensively studied systems in heterogeneous catalysis. Despite this, fundamental understanding of the complex and dynamic chemistry of the

  4. Microemulsion flame pyrolysis for hopcalite nanoparticle synthesis: a new concept for catalyst preparation

    OpenAIRE

    Kaskel, Stefan; Biemelt, Tim; Wegner, Karl; Teichert, Johannes

    2016-01-01

    A new route to highly active hopcalite catalysts via flame spray pyrolysis of an inverse microemulsion precursor is reported. The nitrate derived nanoparticles are around 15 nm in diameter and show excellent conversion of CO under ambient conditions, outperforming commercial reference hopcalite materials produced by co-precipitation.

  5. Microemulsion flame pyrolysis for hopcalite nanoparticle synthesis: a new concept for catalyst preparation.

    Science.gov (United States)

    Biemelt, T; Wegner, K; Teichert, J; Kaskel, S

    2015-04-07

    A new route to highly active hopcalite catalysts via flame spray pyrolysis of an inverse microemulsion precursor is reported. The nitrate derived nanoparticles are around 15 nm in diameter and show excellent conversion of CO under ambient conditions, outperforming commercial reference hopcalite materials produced by co-precipitation.

  6. Synthesis and characterization of Ni-CeO2 catalysts by the hydrothermal method

    International Nuclear Information System (INIS)

    Lazcano O, I.

    2013-01-01

    At the present time the necessity exists to reduce the level of atmospheric pollutants, because these are the main originators of such problems as: the greenhouse effect, acid rain, global heating, among others and that are affecting the human being seriously. In this context, is necessary to look for new solutions that contribute to the improvement of the problems without appealing to limitations in the energy production, because this would imply a non only delay in the economic development, but also in the cultural, technological and of research in our country. An alternative for the energy solution is the use of renewable fuels, because they will decrease the production costs with the time, as well as to diminish the dependence of the fossil fuels, contributing this way to the improvement of the environment quality. The use of the hydrogen as an alternating fuel to the petroleum, is intends as energy solution. The objective of the present work is to develop Ni-CeO 2 catalysts through the hydrothermal method for the hydrogen production starting from the partial oxidation reaction of methanol for the clean fuel generation that does not produce polluting emissions to the environment. As well as, to determine the importance of the metallic load in the catalytic activity for which catalysts to 1 and 2% in weight of Ni were prepared. To achieve these objective different techniques were used to characterize the prepared catalysts, as: Temperature Programmed Reduction to evidence the metal-support interaction, Scanning Electron Microscopy (Sem) to determine the morphology of the catalysts, Surface Area (Bet) with respect to the adsorption-desorption of N 2 and X-Rays Diffraction (XRD) to know the crystalline structure of the catalysts. Also the catalytic properties (activity and selectivity) were studied under the reaction: CH 3 OH + 1/2 O 2 obtaining as products to the CO 2 + 2H 2 , with the help of the multi-tasks equipment Rig-100 that operated to temperatures among

  7. Synthesis and application of different phthalocyanine molecular sieve catalyst for oxidative desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Na; Li, Siwen; Wang, Jinyi; Zhang, Ronglan [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Material Science, Northwest University, Xi’an 710069, Shaanxi (China); Composites Research Institute, Weinan Normal University, Weinan 714000 (China); Gao, Ruimin [Research Institute of Shaanxi Yanchang Petroleum Group Corp. Ltd., Xi’an 710075 (China); Composites Research Institute, Weinan Normal University, Weinan 714000 (China); Zhao, Jianshe, E-mail: jszhao@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Material Science, Northwest University, Xi’an 710069, Shaanxi (China); Composites Research Institute, Weinan Normal University, Weinan 714000 (China); Wang, Junlong [Research Institute of Shaanxi Yanchang Petroleum Group Corp. Ltd., Xi’an 710075 (China); Composites Research Institute, Weinan Normal University, Weinan 714000 (China)

    2015-05-15

    M{sub 2}(PcAN){sub 2} (M=Fe, Co, Ni, Cu, Zn and Mn) anchored onto W-HZSM-5 (M{sub 2}(PcAN){sub 2}–W-HZSM-5) or the M{sub 2}(PcTN){sub 2} doping W-HZSM-5 (M{sub 2}(PcTN){sub 2}/W-HZSM-5) were prepared and their catalytic performances were tested for oxidative desulfurization in the presence of oxygen. Thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT) were considered as sulfur compounds. Among zeolite-based catalysts, the Cu{sub 2}(PcAN){sub 2}–W-HZSM-5 and Cu{sub 2}(PcTN){sub 2}/W-HZSM-5 showed superior desulfurization performance and the activity of selectivity followed the order: T>BT>DBT. The effects of phthalocyanine concentration were studied by UV–Vis and calcination temperature was obtained by TG-DSC for Cu{sub 2}(PcTN){sub 2}/W-HZSM-5. Catalysts were characterized by EA, IR, XRD, SEM, TEM, ICP, and N{sub 2} adsorption. Reaction time, temperature and the amount of catalyst were investigated as the important parameters for optimization of the reaction. Furthermore, a possible process of oxidative desulfurization and the reaction products were proposed. - Graphical abstract: The ODS reaction schematic shows the reaction mechanism of ultra-deep desulfurization. The sulfur compounds are oxidized to their corresponding sulfoxides or sulfones through the use of oxygen and catalysts. The reaction process of ultra-deep desulfurization. - Highlights: • A kind of novel catalyst for deep desulfurization was synthesized. • Cu{sub 2}(PcAN){sub 2}–W-HZSM-5 exhibits excellent catalytic performance for desulfurization. • The reaction conditions that affect desulfurization efficiency are investigated. • The reaction process of model sulfur compounds is proposed.

  8. Synthesis and application of different phthalocyanine molecular sieve catalyst for oxidative desulfurization

    International Nuclear Information System (INIS)

    Zhao, Na; Li, Siwen; Wang, Jinyi; Zhang, Ronglan; Gao, Ruimin; Zhao, Jianshe; Wang, Junlong

    2015-01-01

    M 2 (PcAN) 2 (M=Fe, Co, Ni, Cu, Zn and Mn) anchored onto W-HZSM-5 (M 2 (PcAN) 2 –W-HZSM-5) or the M 2 (PcTN) 2 doping W-HZSM-5 (M 2 (PcTN) 2 /W-HZSM-5) were prepared and their catalytic performances were tested for oxidative desulfurization in the presence of oxygen. Thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT) were considered as sulfur compounds. Among zeolite-based catalysts, the Cu 2 (PcAN) 2 –W-HZSM-5 and Cu 2 (PcTN) 2 /W-HZSM-5 showed superior desulfurization performance and the activity of selectivity followed the order: T>BT>DBT. The effects of phthalocyanine concentration were studied by UV–Vis and calcination temperature was obtained by TG-DSC for Cu 2 (PcTN) 2 /W-HZSM-5. Catalysts were characterized by EA, IR, XRD, SEM, TEM, ICP, and N 2 adsorption. Reaction time, temperature and the amount of catalyst were investigated as the important parameters for optimization of the reaction. Furthermore, a possible process of oxidative desulfurization and the reaction products were proposed. - Graphical abstract: The ODS reaction schematic shows the reaction mechanism of ultra-deep desulfurization. The sulfur compounds are oxidized to their corresponding sulfoxides or sulfones through the use of oxygen and catalysts. The reaction process of ultra-deep desulfurization. - Highlights: • A kind of novel catalyst for deep desulfurization was synthesized. • Cu 2 (PcAN) 2 –W-HZSM-5 exhibits excellent catalytic performance for desulfurization. • The reaction conditions that affect desulfurization efficiency are investigated. • The reaction process of model sulfur compounds is proposed

  9. Bio diesel synthesis from pongamia pinnata oil over modified CeO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Venkatesh; Sathgatta Z, M. S.; Manjunatha, S.; Thammannigowda V, V., E-mail: mohamed.shamshuddin@gmail.com [HMS Institute of Technology, Chemistry Research Laboratory, NH4, Kyathsandra, Tumkur, 572104 Karnataka (India)

    2014-07-01

    This study investigates the use of CeO{sub 2}, ZrO{sub 2}, Mg O and CeO{sub 2}-ZrO{sub 2}, CeO{sub 2}-Mg O, CeO{sub 2}-ZrO{sub 2}-Mg O mixed oxides as solid base catalysts for the transesterification of Pongamia pinnata oil with methanol to produce bio diesel. SO{sub 4}{sup 2-}/CeO{sub 2} and SO{sub 4}{sup 2-}/CeO{sub 2}-ZrO{sub 2} were also prepared and used as solid acid catalysts for esterification of Pongamia pinnata oil (P-oil) to reduce the % of free fatty acid (FFA) in P-oil. The oxide catalysts were prepared by an incipient wetness impregnation method and characterized by techniques such as NH{sub 3}-Tpd for surface acidity, CO{sub 2}-Tpd for surface basicity and powder X-ray diffraction for crystallinity. The effect of nature of the catalyst, methanol to P-oil molar ratio and reaction time in esterification as well as in transesterification was investigated. The catalytic materials were reactive d and reused for five reaction cycles and the results showed that the ceria based catalysts have reasonably good reusability both in esterification and transesterification reaction. The test results also revealed that the CeO{sub 2}-ZrO{sub 2} modified with Mg O could have potential for use in the large scale bio diesel production. (Author)

  10. Green Synthesis of Organics and Nanomaterials and Sustainable Applications of Nano-Catalysts

    Science.gov (United States)

    The presentation summarizes our green chemical synthesis activity involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a variety o...

  11. Greener Synthesis of Organics and Nanomaterials: Sustainable Applications of Nano-Catalysts

    Science.gov (United States)

    The presentation summarizes our recent activity in chemical synthesis involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a varie...

  12. Green Synthesis of Organics and Nanomaterials and Sustainable Applications of Nano-Catalysts- HESTEC

    Science.gov (United States)

    The presentation summarizes our green chemical synthesis activity involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a variety o...

  13. Eco-friendly Synthesis of Organics and Nanomaterials: Sustainable Applications of Nano-Catalysts

    Science.gov (United States)

    The presentation summarizes our recent activity in chemical synthesis involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a varie...

  14. On the deactivation of cobalt-based Fischer-Tropsch synthesis catalysts

    NARCIS (Netherlands)

    Moodley, D.J.

    2008-01-01

    The catalytic conversion of synthesis gas, derived from natural gas, into liquid hydrocarbon fuel via the Fischer–Tropsch synthesis (FTS), is currently receiving much attention due to the demand for environmentally friendly liquid fuel and the rising costs of crude oil. From an industrial

  15. Synthesis of multi-layer graphene and multi-wall carbon nanotubes from direct decomposition of ethanol by microwave plasma without using metal catalysts

    International Nuclear Information System (INIS)

    Rincón, R; Melero, C; Jiménez, M; Calzada, M D

    2015-01-01

    The synthesis of nanostructured carbon materials by using microwave plasmas at atmospheric pressure is presented. This technique involves only one step and without any other supplementary chemical process or metal catalyst. Multi-layer graphene, multi-wall carbon nananotubes and H 2 were obtained by the plasma after ethanol decomposition. Strong emissions of both C 2 molecular bands and C carbon were emitted by the plasma during the process. Futhermore, plasma parameters were studied. Our research shows that both C 2 radicals and high gas temperatures (>3000 K) are required for the synthesis of these materials, which contribute to the understanding of materials synthesis by plasma processes. (fast track communication)

  16. “Flash” Solvent-free Synthesis of Triazoles Using a Supported Catalyst

    Directory of Open Access Journals (Sweden)

    Ibtissem Jlalia

    2009-01-01

    Full Text Available A solvent-free synthesis of 1,4-disubstituted-1,2,3-triazoles using neat azides and alkynes and a copper(I polymer supported catalyst (Amberlyst® A21•CuI is presented herein. As it provides the products in high yields and purities within minutes, this method thus being characterized as a "flash" synthesis, and was exemplified through the synthesis of a 24-compound library on a small scale.

  17. A green synthetic approach toward the synthesis of structurally diverse spirooxindole derivative libraries under catalyst-free conditions.

    Science.gov (United States)

    Kausar, Nazia; Masum, Abdulla Al; Islam, Md Maidul; Das, Asish R

    2017-05-01

    A catalyst-free green methodology for the synthesis of pharmacologically important spirooxindole derivatives has been developed by a three-component domino reaction between isatin, various amino compounds, and 1,3-dicarbonyl or 3-phenylisoxazolone compounds in ethyl L-lactate medium at room temperature. This new efficient synthetic method facilitated the formation of a wide range of biologically significant spirooxindole derivatives (including 17 new spirooxindoles) under very mild conditions. The cytotoxic activity of one of the isoxazole-fused spirooxindoles was evaluated in MDA-MB 468 breast cancer cell line. It was found that cell survivability decreases with increasing concentration of the selected compound in MDA-MB 468 breast cancer cells.

  18. Nb-Based Zeolites: Efficient bi-Functional Catalysts for the One-Pot Synthesis of Succinic Acid from Glucose

    Directory of Open Access Journals (Sweden)

    Magdi El Fergani

    2017-12-01

    Full Text Available The one-pot production of succinic acid from glucose was investigated in pure hot water as solvent using Nb (0.02 and 0.05 moles%-Beta zeolites obtained by a post-synthesis methodology. Structurally, they are comprised of residual framework Al-acid sites, extra-framework isolated Nb (V and Nb2O5 pore-encapsulated clusters. The Nb-modified Beta-zeolites acted as bi-functional catalysts in which glucose is dehydrated to levulinic acid (LA which, further, suffers an oxidation process to succinic acid (SA. After the optimization of the reaction conditions, that is, at 180 °C, 18 bar O2, and 12 h reaction time, the oxidation of glucose occurred with a selectivity to succinic acid as high as 84% for a total conversion.

  19. Disproportionation phenema of wistite phase in the model iron catalysts for ammonia synthesis studied by Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Pattek-Janczyk, A.; Miczko, B.

    1990-01-01

    A model iron catalysts for ammonia synthesis containing a large amount of wustite (35 wt%) has been studied during the annealing in an inert atmosphere in the temperature range of 573-773 K. Changes in magnetite and wustite phases were followed by Muessbauer spectroscopy (MS). Before starting the thermal treatment, two kinds of wustite of different structures have been found by MS and X-ray diffraction. The behaviour of both kinds of wustite during the annealing was different. One of them, closer to the stoichiometric compound, disproportionated at once into magnetite and iron; its content decreased systematically without changes in the Muessbauer parameters. In the second wustite, only qualitatieve changes were observed at first (its nonstoichiometry decreases without changes in content and, next, this phase started to disproportionate too. (auhtor). 31 refs.; 6 figs.; 2 tabs

  20. X-ray physico-chemical imaging during activation of cobalt-based Fischer-Tropsch synthesis catalysts

    Science.gov (United States)

    Beale, Andrew M.; Jacques, Simon D. M.; Di Michiel, Marco; Mosselmans, J. Frederick W.; Price, Stephen W. T.; Senecal, Pierre; Vamvakeros, Antonios; Paterson, James

    2017-11-01

    The imaging of catalysts and other functional materials under reaction conditions has advanced significantly in recent years. The combination of the computed tomography (CT) approach with methods such as X-ray diffraction (XRD), X-ray fluorescence (XRF) and X-ray absorption near-edge spectroscopy (XANES) now enables local chemical and physical state information to be extracted from within the interiors of intact materials which are, by accident or design, inhomogeneous. In this work, we follow the phase evolution during the initial reduction step(s) to form Co metal, for Co-containing particles employed as Fischer-Tropsch synthesis (FTS) catalysts; firstly, working at small length scales (approx. micrometre spatial resolution), a combination of sample size and density allows for transmission of comparatively low energy signals enabling the recording of `multimodal' tomography, i.e. simultaneous XRF-CT, XANES-CT and XRD-CT. Subsequently, we show high-energy XRD-CT can be employed to reveal extent of reduction and uniformity of crystallite size on millimetre-sized TiO2 trilobes. In both studies, the CoO phase is seen to persist or else evolve under particular operating conditions and we speculate as to why this is observed. This article is part of a discussion meeting issue 'Providing sustainable catalytic solutions for a rapidly changing world'.

  1. Rh-Based Mixed Alcohol Synthesis Catalysts: Characterization and Computational Report

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, Karl O.; Glezakou, Vassiliki Alexandra; Rousseau, Roger J.; Engelhard, Mark H.; Varga, Tamas; Colby, Robert J.; Jaffe, John E.; Li, Xiaohong S.; Mei, Donghai; Windisch, Charles F.; Kathmann, Shawn M.; Lemmon, Teresa L.; Gray, Michel J.; Hart, Todd R.; Thompson, Becky L.; Gerber, Mark A.

    2013-08-01

    The U.S. Department of Energy is conducting a program focused on developing a process for the conversion of biomass to bio-based fuels and co-products. Biomass-derived syngas is converted thermochemically within a temperature range of 240 to 330°C and at elevated pressure (e.g., 1200 psig) over a catalyst. Ethanol is the desired reaction product, although other side compounds are produced, including C3 to C5 alcohols; higher (i.e., greater than C1) oxygenates such as methyl acetate, ethyl acetate, acetic acid and acetaldehyde; and higher hydrocarbon gases such as methane, ethane/ethene, propane/propene, etc. Saturated hydrocarbon gases (especially methane) are undesirable because they represent a diminished yield of carbon to the desired ethanol product and represent compounds that must be steam reformed at high energy cost to reproduce CO and H2. Ethanol produced by the thermochemical reaction of syngas could be separated and blended directly with gasoline to produce a liquid transportation fuel. Additionally, higher oxygenates and unsaturated hydrocarbon side products such as olefins also could be further processed to liquid fuels. The goal of the current project is the development of a Rh-based catalyst with high activity and selectivity to C2+ oxygenates. This report chronicles an effort to characterize numerous supports and catalysts to identify particular traits that could be correlated with the most active and/or selective catalysts. Carbon and silica supports and catalysts were analyzed. Generally, analyses provided guidance in the selection of acceptable catalyst supports. For example, supports with high surface areas due to a high number of micropores were generally found to be poor at producing oxygenates, possibly because of mass transfer limitations of the products formed out of the micropores. To probe fundamental aspects of the complicated reaction network of CO with H2, a computational/ theoretical investigation using quantum mechanical and ab

  2. Synthesis of palladium nanoparticles with leaf extract of Chrysophyllum cainito (Star apple) and their applications as efficient catalyst for C-C coupling and reduction reactions

    Science.gov (United States)

    Majumdar, Rakhi; Tantayanon, Supawan; Bag, Braja Gopal

    2017-10-01

    A simple green chemical method for the one-step synthesis of palladium nanoparticles (PdNPs) has been described by reducing palladium (II) chloride with the leaf extract of Chrysophyllum cainito in aqueous medium. The synthesis of the palladium nanoparticles completed within 2-3 h at room temperature, whereas on heat treatment (70-80 °C), the synthesis of colloidal PdNPs completed almost instantly. The stabilized PdNPs have been characterized in detail by spectroscopic, electron microscopic and light scattering measurements. The synthesized PdNPs have been utilized as a green catalyst for C-C coupling reactions under aerobic and phosphine-free conditions in aqueous medium. In addition, the synthesized PdNPs have also been utilized as a catalyst for a very efficient sodium borohydride reduction of 3- and 4-nitrophenols. The synthesized PdNPs can retain their catalytic activity for several months.

  3. A Comparative Characterization of the HPA-MCM-48 Type Catalysts Produced by the Direct Hydrothermal and Room Temperature Synthesis Methods

    International Nuclear Information System (INIS)

    Gucbilmez, Y.; Calis, I.; Yargic, A. S.

    2012-01-01

    MCM-48 type support materials synthesized by the direct hydrothermal synthesis (HTS) and room temperature synthesis (RTS) methods were incorporated with tungstophosphoric acid (TPA) in the range of 10-40 wt% by using a wet impregnation technique in methanol solutions. Resulting HPA-MCM-48 catalysts were characterized by the XRD, Nitrogen Physisorption, SEM, TEM, EDS, and FT-IR methods in order to determine the effects of different initial synthesis conditions on the catalyst properties. RTS samples were found to have better crystalline structures, higher BET surface areas, and higher BJH pore volumes than HTS samples. They also had slightly higher TPA incorporation, except for the 40 wt% samples, as evidenced by the EDS results. Keggin ion structure was preserved, for both methods, even at the highest acid loading of 40 wt%. It was concluded that the simpler and more economical RTS method was more successful than the HTS method for hetero poly acid incorporation into MCM-48 type materials

  4. Hydrogen production by ethanol partial oxidation over nano-iron oxide catalysts produced by chemical vapour synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Wael Ahmed Abou Taleb Sayed

    2011-01-13

    This work presents the experimental results of the synthesis of unsupported and supported SiC iron oxide nanoparticles and their catalytic activity towards ethanol partial oxidation. For comparison, further unsupported iron oxide phases were investigated towards the ethanol partial oxidation. These {gamma}-Fe{sub 2}O{sub 3} and {alpha}/{gamma}-Fe{sub 2}O{sub 3} phase catalysts were prepared by the CVS method using Fe(CO){sub 5} as precursor, supplied by another author. The {alpha}-Fe{sub 2}O{sub 3} and SiC nanoparticles were prepared by the CVS method using a home made hot wall reactor technique at atmospheric pressure. Ferrocene and tetramethylsilane were used as precursor for the production process. Process parameters of precursor evaporation temperature, precursor concentration, gas mixture velocity and gas mixture dilution were investigated and optimised to produce particle sizes in a range of 10 nm. For Fe{sub 2}O{sub 3}/SiC catalyst series production, a new hot wall reactor setup was used. The particles were produced by simultaneous thermal decomposition of ferrocene and tetramethylsilane in one reactor from both sides. The production parameters of inlet tube distance inside the reactor, precursor evaporation temperature and carrier gas flow were investigated to produce a series of samples with different iron oxide content. The prepared catalysts composition, physical and chemical properties were characterized by XRD, EDX, SEM, BET surface area, FTIR, XPS and dynamic light scattering (DLS) techniques. The catalytic activity for the ethanol gas-phase oxidation was investigated in a temperature range from 260 C to 290 C. The product distributions obtained over all catalysts were analysed with mass spectrometry analysis tool. The activity of bulk Fe{sub 2}O{sub 3} and SiC nanoparticles was compared with prepared nano-iron oxide phase catalysts. The reaction parameters, such as reaction temperature and O{sub 2}/ethanol ratio were investigated. The catalysts

  5. Facile and large-scale synthesis of high quality few-layered graphene nano-platelets via methane decomposition over unsupported iron family catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Awadallah, Ahmed E., E-mail: ahmedelsayed_epri@yahoo.com [Process Development Division, Egyptian Petroleum Research Institute, 11727 Cairo (Egypt); Aboul-Enein, Ateyya A. [Process Development Division, Egyptian Petroleum Research Institute, 11727 Cairo (Egypt); Kandil, Usama F. [Petroleum Application Department, Egyptian Petroleum Research Institute, 11727 Cairo (Egypt); Taha, Mahmoud Reda [Department of Civil Engineering, University of New Mexico, Albuquerque, NM 87131 (United States)

    2017-04-15

    High quality few-layered graphene nano-platelets (GNPs) were successfully prepared via catalytic chemical vapor deposition of methane under ambient pressure using substrate-free unsupported iron, cobalt, and nickel metallic sheets as catalysts. The bulk catalysts were prepared via combustion method using citric acid as a fuel. Various analytical techniques, including high-resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), temperature programmed reduction (TPR) and Raman spectroscopy were employed to characterize the fresh and reduced catalysts and to identify the morphological structure of the as-grown GNPs. TEM images of the reduced metal catalysts showed that polycrystalline metallic sheets were easily produced after complete reduction of unsupported metal oxides. The data demonstrated that the formation of zero-valent metallic sheets could effectively promote the growth of GNPs on their surfaces. The unsupported Ni catalyst exhibits higher catalytic growth activity in terms of GNPs yield (254 wt%) compared with all other catalysts. Raman spectra and TEM results established that a few layers of GNPs with high crystallinity and good graphitization were produced. TGA results further demonstrated that the as-grown GNPs exhibit significantly higher thermal stability in air atmosphere compared with other synthesis methods. - Highlights: • Few-layered graphene nanoplatelets were prepared via methane catalytic decomposition. • Metallic sheets of iron group metals were used as novel catalysts. • The surfaces of metallic sheets were found to be very effective for GNPs growth. • The number of layers is dependent on the morphological structure of the catalysts. • The unsupported metallic Ni catalyst exhibited higher catalytic growth activity.

  6. Catalyst-Free Synthesis of Hollow-Sphere-Like ZnO and Its Photoluminescence Property

    Directory of Open Access Journals (Sweden)

    Junye Cheng

    2014-01-01

    Full Text Available Hollow-sphere-like ZnO was successfully prepared by a facile combustion route at 950°C, and no external catalysts or additives were introduced. The morphology and structure of the hollow-sphere-like ZnO were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, high-resolution transmission electron microscopy (HRTEM, and energy dispersive spectrometer (EDS. The possible growth mechanism was discussed in detail. In addition, the as-obtained hollow-sphere-like ZnO exhibited a strong green emission at 518 nm and a weak UV emission at 385 nm. We believe that the hollow-sphere-like ZnO material may be a good candidate for application in optical devices and catalyst systems.

  7. Flame synthesis of carbon nano onions using liquefied petroleum gas without catalyst

    International Nuclear Information System (INIS)

    Dhand, Vivek; Prasad, J. Sarada; Rao, M. Venkateswara; Bharadwaj, S.; Anjaneyulu, Y.; Jain, Pawan Kumar

    2013-01-01

    Densely agglomerated, high specific surface area carbon nano onions with diameter of 30–40 nm have been synthesized. Liquefied petroleum gas and air mixtures produced carbon nano onions in diffusion flames without catalyst. The optimized oxidant to fuel ratio which produces carbon nano onions has been found to be 0.1 slpm/slpm. The experiment yielded 70% pure carbon nano onions with a rate of 5 g/h. X-ray diffraction, high-resolution electron microscopy and Raman spectrum reveal the densely packed sp 2 hybridized carbon with (002) semi-crystalline hexagonal graphite reflection. The carbon nano onions are thermally stable up to 600 °C. - Highlights: ►Flame synthesized carbon nano onions with 30–40 nm diameters. ►LPG/air, diffusion type flame used in absence of catalyst to produce nano onions. ►Carbon nano onion production rate is 5 g/hr and with 70% purity.

  8. Revealing the Cytotoxicity of Residues of Phosphazene Catalysts Used for Synthesis of Poly(ethylene oxide)

    KAUST Repository

    Xia, Yening

    2017-08-24

    We herein report a case study on the toxicity of residual catalyst in metal-free polymer. Eight-arm star-like poly(ethylene oxide)s were successfully synthesized via phosphazene-catalyzed ring-opening polymerization of ethylene oxide using sucrose as an octahydroxy initiator. The products were subjected to MTT assay using human cancer cell lines (MDA-MB-231 and A2780). Comparison between the crude and purified products clearly revealed that the residual phosphazenium salts were considerably cytotoxic regardless of the anionic species, and that the cytotoxicity of more bulky t-BuP4 salt was higher than that of t-BuP2 salt. Such results have therefore put forward the necessity for removal of the catalyst residues from PEO-based polymers synthesized through phosphazene catalysis for bio-related applications, and for the development of less or non-toxic organocatalysts for such polymers.

  9. Revealing the Cytotoxicity of Residues of Phosphazene Catalysts Used for Synthesis of Poly(ethylene oxide)

    KAUST Repository

    Xia, Yening; Shen, Jizhou; Alamri, Haleema; Hadjichristidis, Nikolaos; Zhao, Junpeng; Wang, Yucai; Zhang, Guangzhao

    2017-01-01

    We herein report a case study on the toxicity of residual catalyst in metal-free polymer. Eight-arm star-like poly(ethylene oxide)s were successfully synthesized via phosphazene-catalyzed ring-opening polymerization of ethylene oxide using sucrose as an octahydroxy initiator. The products were subjected to MTT assay using human cancer cell lines (MDA-MB-231 and A2780). Comparison between the crude and purified products clearly revealed that the residual phosphazenium salts were considerably cytotoxic regardless of the anionic species, and that the cytotoxicity of more bulky t-BuP4 salt was higher than that of t-BuP2 salt. Such results have therefore put forward the necessity for removal of the catalyst residues from PEO-based polymers synthesized through phosphazene catalysis for bio-related applications, and for the development of less or non-toxic organocatalysts for such polymers.

  10. An Efficient and Recyclable Nanoparticle-Supported Cobalt Catalyst for Quinoxaline Synthesis

    Directory of Open Access Journals (Sweden)

    Fatemeh Rajabi

    2015-11-01

    Full Text Available The syntheses of quinoxalines derived from 1,2-diamine and 1,2-dicarbonyl compounds under mild reaction conditions was carried out using a nanoparticle-supported cobalt catalyst. The supported nanocatalyst exhibited excellent activity and stability and it could be reused for at least ten times without any loss of activity. No cobalt contamination could be detected in the products by AAS measurements, pointing to the excellent activity and stability of the Co nanomaterial.

  11. Synthesis of Acrolein From Glycerol Using FePO4 Catalyst in Liquid Phase Dehydration

    OpenAIRE

    Abidin, Akhmad Zainal; Afandi, Rani Guslianti; Graha, Hafis Pratama Rendra

    2016-01-01

    Acrolein is currently produced using propylene from crude oil while its price and scarcity are increasing. A renewable material such as glycerol is an attractive alternative for acrolein production. It can be obtained from crude palm oil (CPO) and is a byproduct of biodiesel production. Besides being able to compete economically, glycerol is an environmentally friendly material. The purpose of this study is to synthesize acrolein from glycerol using FePO4 catalyst in liquid phase dehydration....

  12. Pt-Ni and Pt-Co Catalyst Synthesis Route for Fuel Cell Applications

    Science.gov (United States)

    Firdosy, Samad A.; Ravi, Vilupanur A.; Valdez, Thomas I.; Kisor, Adam; Narayan, Sri R.

    2013-01-01

    Oxygen reduction reactions (ORRs) at the cathode are the rate-limiting step in fuel cell performance. The ORR is 100 times slower than the corresponding hydrogen oxidation at the anode. Speeding up the reaction at the cathode will improve fuel cell efficiency. The cathode material is generally Pt powder painted onto a substrate (e.g., graphite paper). Recent efforts in the fuel cell area have focused on replacing Pt with Pt-X alloys (where X = Co, Ni, Zr, etc.) in order to (a) reduce cost, and (b) increase ORR rates. One of these strategies is to increase ORR rates by reducing the powder size, which would result in an increase in the surface area, thereby facilitating faster reaction rates. In this work, a process has been developed that creates Pt-Ni or Pt-Co alloys that are finely divided (on the nano scale) and provide equivalent performance at lower Pt loadings. Lower Pt loadings will translate to lower cost. Precursor salts of the metals are dissolved in water and mixed. Next, the salt mixtures are dried on a hot plate. Finally, the dried salt mixture is heattreated in a furnace under flowing reducing gas. The catalyst powder is then used to fabricate a membrane electrode assembly (MEA) for electrochemical performance testing. The Pt- Co catalyst-based MEA showed comparable performance to an MEA fabri cated using a standard Pt black fuel cell catalyst. The main objective of this program has been to increase the overall efficiencies of fuel cell systems to support power for manned lunar bases. This work may also have an impact on terrestrial programs, possibly to support the effort to develop a carbon-free energy source. This catalyst can be used to fabricate high-efficiency fuel cell units that can be used in space as regenerative fuel cell systems, and terrestrially as primary fuel cells. Terrestrially, this technology will become increasingly important when transition to a hydrogen economy occurs.

  13. Synthesis of gold nano-catalysts supported on carbon nanotubes by using electroless plating technique

    International Nuclear Information System (INIS)

    Ma Xicheng; Li Xia; Lun Ning; Wen Shulin

    2006-01-01

    Gold nanoparticles supported on carbon nanotubes were prepared by using electroless plating technique. High-resolution transmission electron microscopy (HRTEM) has shown that spherical gold nanoparticles were homogeneously dispersed on the surfaces of the carbon nanotubes with a distribution of particle sizes sharply at around 3-4 nm in diameter. The results presented in this work will probably provide new catalysts with better performances

  14. Nano-Ticl 4 .SiO 2 : a Versatile and Efficient Catalyst for Synthesis of ...

    African Journals Online (AJOL)

    Nano-TiCl4.SiO2 has been found to be an extremely efficient catalyst for the preparation of 3,4-dihydropyrimidinones/thiones via three-component reactions of an aldehyde, β-ketoester or β-diketone and urea or thiourea under mild conditions. Nano-TiCl4.SiO2 as a solid Lewis acid has been synthesized by reaction of ...

  15. Facial synthesis of porous hematite supported Pt catalyst and its photo enhanced electrocatalytic ethanol oxidation performance

    International Nuclear Information System (INIS)

    Kang, Shuai; Shen, Pei Kang

    2015-01-01

    Graphical Abstract: A porous α-Fe 2 O 3 supported Pt catalyst has been synthesized by a facial thermal treatment assisted precipitation method and the materials show a illumination enhanced performance for ethanol oxidation. Display Omitted -- Highlights: •A porous α-Fe 2 O 3 supported Pt catalyst has been synthesized for the first time. •With the addition of α-Fe 2 O 3 , the current density of Pt/C grows about 51% under illumination and 32% in the dark compared with unsupported catalyst. •The current increases under illuminationin chronoamperometric experiments at a given potential of 0.7 V due to the photons from light provide energy for CO stripping. •This work demostrates an optical strategy to accelerate electrode reactions towards ethanol oxidation reaction. -- Abstract: The porous α-Fe 2 O 3 supported Pt catalyst is synthesized by a facial thermal treatment assisted precipitation method. The particle size of Pt is less than 3 nm. The pore diameters of α-Fe 2 O 3 particles are concentrated to 2.46 nm in a mesooporous scale. Its electrochemical performance is tested. The ethanol oxidation current of the Pt/Fe 2 O 3 catalsyt obviously improves under illumination, compared with that in the dark, during the optical switching operation. Moreover, with the addition of α-Fe 2 O 3 , the ethanol oxidation current of Pt/C grows about 51% under illumination and 32% in the dark; the onset potential shifts negtively for about 20 mV. This work demostrates an optical strategy which can be a potential alternative to accelerate electrode reactions towards ethanol oxidation reaction

  16. Facile one-pot synthesis of porphyrin based porous polymer networks (PPNs) as biomimetic catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zou, LF; Feng, DW; Liu, TF; Chen, YP; Fordham, S; Yuan, S; Tian, J; Zhou, HC

    2015-01-01

    Stable porphyrin based porous polymer networks, PPN-23 and PPN-24, have been synthesized through a facile one-pot approach by the aromatic substitution reactions of pyrrole and aldehydes. PPN-24(Fe) shows high catalytic efficiency as a biomimetic catalyst in the oxidation reaction of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) in the presence of H2O2.

  17. Dry re-forming of methane to synthesis gas over lignite semicokes catalyst at high pressure

    Directory of Open Access Journals (Sweden)

    Fengbo Guo

    2016-11-01

    Full Text Available Dry re-forming of methane has been carried out in a high temperature–pressure reactor at different pressures, using Hongce lignite semicokes catalyst. The results show that CH4 and CO2 conversions are decreased as the reaction pressure increased, but both of them kept basically stable when the reaction pressure is between 0.3 and 1 MPa. The comparison shows that the effects of the temperature and the flow of reactant gas on dry re-forming of methane are consistent with between high pressure and atmospheric pressure. The ratio of CO/H2 decreased as the ratio of CH4/CO2 increased, yet the value of CO/H2 is always more than 1 at different pressures. Hongce lignite semicokes catalyst is characterized by FTIR, XRD, SEM and BET, and the analysis results reveled that the physical specific adsorption peak of CO2 at 2350 cm−1 is strengthened significantly at different pressures, the micropore area and volume of Hongce lignite semicokes reduced form 40.2 m2  g−1 and 0.019 cm3  g−1 to 34.9 m2  g−1 and 0.017 cm3  g−1, respectively. Hongce lignite semicokes catalyst exhibited better activity and stability within 0.3–1 MPa range.

  18. Flame spray synthesis of CoMo/Al2O3 hydrotreating catalysts

    DEFF Research Database (Denmark)

    Høj, Martin; Linde, Kasper; Hansen, Thomas Klint

    2011-01-01

    containing 16wt.% Mo (atomic ratio Co/Mo=1/3), which did not contain crystalline MoO3 and only small amounts of CoAl2O4. The hydrotreating activity was approximately 75% of that of commercial cobalt molybdenum catalysts prepared by wet impregnation of pre-shaped alumina extrudates. Since the commercial...... obtained consisted mostly of γ-Al2O3 with some CoAl2O4, as evidenced by X-ray diffraction (XRD) and UV–vis spectroscopy. Bulk MoO3 was not detected by XRD, except at the highest molybdenum content (32wt.%) and in the unsupported sample, indicating that molybdenum is well dispersed on the surface.......After activation by sulfidation the activity of the catalysts were measured for the three hydrotreating reactions hydrodesulfurization, hydrodenitrogenation and hydrogenation using a model oil containing dibenzothiophene, indole and naphthalene in n-heptane solution. The best catalyst was the FSP-produced material...

  19. Synthesis and characterization of novel intermetallic catalysts for hydrogenation of carbon dioxide to methanol

    DEFF Research Database (Denmark)

    Fiordaliso, Elisabetta Maria; Sharafutdinov, Irek; Chorkendorff, Ib

    Novel Ni5Ga3 and Pd2Ga catalysts for CO2 hydrogenation to methanol are prepared by impregnation of aqueous Ni-Ga or Pd-Ga solutions of metal nitrates into high surface area SiO2, followed by drying, calcinations and reduction of the precursor in a H2 flow. Steady state experiments are performed...... in a reactor at atmospheric pressure and stoichiometric CO2/H2 mixture, while reaction products are analyzed by gas chromatography. The results are compared to the highly optimized Cu/ZnO/Al2O3. The activity and selectivity of the novel catalysts is close to that of Cu/ZnO/Al2O3 and the equilibrium conversion...... to CH3OH is found to be higher. XRD and XRF are used to investigate the phase and composition of the supported catalysts at the 5 stages of testing, i.e. after drying, calcination, reduction, CO2 hydrogenation, rapid ageing. SEM and TEM images of the exact same locations are acquired after each of the 5...

  20. Synthesis of carbon-supported copper catalyst and its catalytic performance in methanol dehydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Shelepova, Ekaterina V. [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk, 630090 (Russian Federation); National Research Tomsk Polytechnic University, Lenin av., 30, Tomsk, 634050 (Russian Federation); Vedyagin, Aleksey A., E-mail: vedyagin@catalysis.ru [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk, 630090 (Russian Federation); National Research Tomsk Polytechnic University, Lenin av., 30, Tomsk, 634050 (Russian Federation); Ilina, Ludmila Yu.; Nizovskii, Alexander I. [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk, 630090 (Russian Federation); Tsyrulnikov, Pavel G. [Institute of Hydrocarbon Processing SB RAS, Neftezavodskaya st., 54, Omsk, 644040 (Russian Federation)

    2017-07-01

    Highlights: • Carbon-supported copper catalyst was studied in dehydrogenation of methanol. • Reduction temperature affected size of Cu particles and Cu{sup 0}/Cu{sup 2+} ratio. • Reduction at 400 °C was required to obtain high methyl formate yield. - Abstract: Carbon-supported copper catalyst was prepared by incipient wetness impregnation of Sibunit with an aqueous solution of copper nitrate. Copper loading was 5 wt.%. Temperature of reductive pretreatment was varied within a range of 200–400 °C. The samples were characterized by transmission electron microscopy, X-ray diffraction analysis, X-ray photoelectron and X-ray absorption spectroscopies. Catalytic activity of the samples was studied in a reaction of methanol dehydrogenation. Silica-based catalyst with similar copper loading was used as a reference. It was found that copper is distributed over the surface of support in the form of metallic and partially oxidized particles of about 12–17 nm in size. Diminished interaction of copper with support was supposed to be responsible for high catalytic activity.

  1. Hydrothermal synthesis of bismuth ferrite Fenton-like catalysts and their properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Min; Li, Wenjuan, E-mail: liwenjuan2801@163.com; Du, Yong; Kong, Defen; Wang, Ze; Meng, Yi; Sun, Xiaolan; Yan, Tingjiang; Kong, Desheng; You, Jinmao [Qufu Normal University, Shandong Province Key Laboratory of Life-Organic Analysis (China)

    2016-11-15

    Bismuth ferrite, Fenton-like catalysts have been successfully synthesized via simple hydrothermal methods without any templates. Through changing the molar ratio of Bi/Fe, the two main phases BiFeO{sub 3} and Bi{sub 25}FeO{sub 40} can be synthesized under different temperatures. Furthermore, different morphologies of the BiFeO{sub 3} phase can be adjusted by changing different concentrations of HNO{sub 3} and NaOH which were used to dissolve the reactants and adjust the pH values in the prepared process. When the concentration of HNO{sub 3}/NaOH was 8/12 M, some uniform cylindrical bodies with equal height (1 μm) and width (0.6 μm) were obtained, which have not been reported before. The uniform structures exhibited better activities in the photoassisted Fenton-like oxidation process for the degradation of rhodamine B (RhB) under visible light irradiation (420 nm < λ < 800 nm). Through the detection of the degradation mechanism, it showed that the concerted effect of the catalysts and H{sub 2}O{sub 2} can increase the generation of the charge carriers and accelerate the photogenerated charge transfer between the catalysts and dyes. The BiFeO{sub 3} samples also showed magnetic properties at room temperature, which may have potential applications in multiferroic or magnetoelectric sensors and devices.

  2. Synthesis and application of different phthalocyanine molecular sieve catalyst for oxidative desulfurization

    Science.gov (United States)

    Zhao, Na; Li, Siwen; Wang, Jinyi; Zhang, Ronglan; Gao, Ruimin; Zhao, Jianshe; Wang, Junlong

    2015-05-01

    M2(PcAN)2 (M=Fe, Co, Ni, Cu, Zn and Mn) anchored onto W-HZSM-5 (M2(PcAN)2-W-HZSM-5) or the M2(PcTN)2 doping W-HZSM-5 (M2(PcTN)2/W-HZSM-5) were prepared and their catalytic performances were tested for oxidative desulfurization in the presence of oxygen. Thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT) were considered as sulfur compounds. Among zeolite-based catalysts, the Cu2(PcAN)2-W-HZSM-5 and Cu2(PcTN)2/W-HZSM-5 showed superior desulfurization performance and the activity of selectivity followed the order: T>BT>DBT. The effects of phthalocyanine concentration were studied by UV-Vis and calcination temperature was obtained by TG-DSC for Cu2(PcTN)2/W-HZSM-5. Catalysts were characterized by EA, IR, XRD, SEM, TEM, ICP, and N2 adsorption. Reaction time, temperature and the amount of catalyst were investigated as the important parameters for optimization of the reaction. Furthermore, a possible process of oxidative desulfurization and the reaction products were proposed. The reaction process of ultra-deep desulfurization.

  3. Synthesis, characterization and dielectric properties of polynorbornadiene–clay nanocomposites by ROMP using intercalated Ruthenium catalyst

    International Nuclear Information System (INIS)

    Yalçınkaya, Esra Evrim; Balcan, Mehmet; Güler, Çetin

    2013-01-01

    Polynorbornadiene clay nanocomposites were prepared for the first time by the ring opening metathesis polymerization (ROMP) using modified montmorillonite and polynorbornadiene the latter of which is used commonly in electric–electronic industry. The Na–MMT clay was modified by a quaternary ammonium salt containing Ruthenium complex as a suitable catalyst and intercalant as well. The norbornadiene monomers were polymerized within the modified montmorillonite layers by in-situ polymerization method in different clay loading degrees. Intercalation ability of the Ru catalyst and partially exfoliated nanocomposite structure were proved by powder X-ray Diffraction (XRD) Spectroscopy and Transmission Electron Microscopy (TEM) methods. The nanocomposite materials with high thermal degradation temperature and low dielectric constant compared to the pure polynorbornadiene were obtained. The dielectric constants decreased with the increase of the clay content. - Highlights: • Polynorbornadiene–clay nanocomposites were prepared for the first time. • Ruthenium complex was assigned as both suitable catalyst and intercalant. • The norbornadiene was polymerized by in-situ polymerization method. • Exfoliation/intercalation structures were found to be related with loading degree. • PNBD–MMT nanocomposites had a higher thermal degradation temperature and lower dielectric constant

  4. Cross-linked lysozyme crystal templated synthesis of Au nanoparticles as high-performance recyclable catalysts

    International Nuclear Information System (INIS)

    Liang Miao; Liu Xia; Qi Wei; Su Rongxin; Huang Renliang; Yu Yanjun; He Zhimin; Wang Libing

    2013-01-01

    Bio-nanomaterials fabricated using a bioinspired templating technique represent a novel class of composite materials with diverse applications in biomedical, electronic devices, drug delivery, and catalysis. In this study, Au nanoparticles (NPs) are synthesized within the solvent channels of cross-linked lysozyme crystals (CLLCs) in situ without the introduction of extra chemical reagents or physical treatments. The as-prepared AuNPs-in-protein crystal hybrid materials are characterized by light microscopy, transmission electron microscopy, x-ray diffraction, and Fourier-transform infrared spectroscopy analyses. Small AuNPs with narrow size distribution reveal the restriction effects of the porous structure in the lysozyme crystals. These composite materials are proven to be active heterogeneous catalysts for the reduction of 4-nitrophenol to 4-aminophenol. These catalysts can be easily recovered and reused at least 20 times because of the physical stability and macro-dimension of CLLCs. This work is the first to use CLLCs as a solid biotemplate for the preparation of recyclable high-performance catalysts. (paper)

  5. Application of Ce{sub x}Zr{sub 1-x}O{sub 2} catalysts for the synthesis of diethyl carbonate from ethanol and carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Prymak, I.; Kalevaru, V.N.; Kollmorgen, P.; Wohlrab, S. [Leibniz-Institut fuer Katalyse e.V. an der Universitaet Rostock (Germany); Martin, A.

    2013-11-01

    The direct synthesis of diethyl carbonate (DEC) from ethanol and CO{sub 2} is indeed an attractive approach from both academic and commercial points of view. In the present study, we report on the synthesis, characterization and catalytic evaluation of Ce-Zr-O solids with varying Ce/Zr ratios. The catalysts were prepared by citrate complexation method, and characterized by various techniques such as N{sub 2} adsorption (BET-SA), XRD, H{sub 2}-TPR, NH{sub 3}-TPD etc. The catalytic performance of these catalysts was evaluated towards the synthesis of DEC from ethanol and CO{sub 2} under suitable reaction conditions. According to thermodynamic data, the reaction is favorable at low reaction temperatures and high reaction pressures. Thus, the catalytic experiments were carried out in a continuous mode using a plug-flow reactor that was operated up to 200 bar and ca. 200 C. The effect of the reaction temperature (30-180 C) and pressure (80-180 bar) on the yield of DEC was investigated. Among various catalysts tested, Ce-Zr-O catalyst with 80 mol% Ce content has exhibited a relatively better performance compared to all other Ce-Zr-O catalysts. DEC yield increased with increasing reaction temperature up to 140 C. The highest yield of DEC obtained from the best case was 0.7 % at 140 C and at 140 bars. Further increase in temperature to 180 C caused a decrease in the DEC formation due to thermodynamic reasons as mentioned above. The ceria proportion has shown a considerable influence on the BET surface areas and thereby catalytic activity as well. The results revealed that the redox properties as well as acidity characteristics of the solids are strongly influenced by the content of Ce in the catalysts, which in turn showed a clear impact on the catalytic performance. (orig.)

  6. Tannic Acid an Efficient Catalyst for the Synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one Derivatives

    Directory of Open Access Journals (Sweden)

    Deepak S. Kawade

    2015-06-01

    Full Text Available Tannic acid explore a highly efficient catalytic activity for the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one derivatives in excellent yields via cyclocondensation of aromatic aldehyde, β-naphthol and dimedone. Catalyst having advantages such as it is cheap and biodegradable and the protocol avoids the use of expensive catalyst and toxic solvent. We believe that this methodology is an efficient, simple, highly yielding, time saving and environmentally friendly. DOI: http://dx.doi.org/10.17807/orbital.v7i2.683

  7. A general approach for the synthesis of bimetallic M–Sn (M = Ru, Rh and Ir) catalysts for efficient hydrogenolysis of ester

    KAUST Repository

    Samal, Akshaya Kumar

    2016-11-24

    A versatile synthetic method was applied for the preparation of Sn containing bimetallic catalysts. The synthesis was performed by simply mixing the super hydride [LiB(C2H5)(3)H], with a metal (Ru, Rh or Ir) salt and an organotin complex in tetrahydrofuran solvent without using any surfactant. This leads to the formation of monodispersed M-Sn (M = Ru, Rh or Ir) bimetallic nanoparticles (NPs). These bimetallic catalysts show high performances in the hydrogenolysis of ester to the corresponding alcohol.

  8. KF/Al2O3 as a Recyclable Basic Catalyst for 1,3-Dipolar Cycloaddition Reaction: Synthesis of Indolizine-1-Carbonitrile Derivatives

    Directory of Open Access Journals (Sweden)

    Abaszadeh Mehdi

    2017-07-01

    Full Text Available KF/Al2O3 as a green and efficient catalyst has been used for synthesis of indolizine-1-carbonitrile derivatives. It can be proceeded by using 1,3-dipolar cycloaddition reaction of 1-alkyl-2-chloropyridinium bromides, malononitrile and benzaldehyde in ethanol, at reflux. The great advantage of this catalyst is the ease of handling. KF/Al2O3 can be used and removed by filtration, avoiding cumbersome aqueous workups and decreasing solvent waste handling issues. High conversions, short reaction times and a cleaner reaction profiles are some of the outstanding advantages of this method.

  9. Selective Synthesis of Gasoline-Ranged Hydrocarbons from Syngas over Hybrid Catalyst Consisting of Metal-Loaded ZSM-5 Coupled with Copper-Zinc Oxide

    Directory of Open Access Journals (Sweden)

    Ting Ma

    2014-04-01

    Full Text Available The conversion of syngas (CO + H2 to gasoline-ranged hydrocarbons was carried out using a hybrid catalyst consisting of metal-loaded ZSM-5 coupled with Cu-ZnO in a near-critical n-hexane solvent. Methanol was synthesized from syngas over Cu-ZnO; subsequently, was converted to hydrocarbons through the formation of dimethyl ether (DME over the metal-loaded ZSM-5. When 0.5 wt% Pd/ZSM-5 and 5 wt% Cu/ZSM-5 among the metal-loaded ZSM-5 catalysts with Pd, Co, Fe or Cu were employed as a portion of the hybrid catalyst, the gasoline-ranged hydrocarbons were selectively produced (the gasoline-ranged hydrocarbons in all hydrocarbons: 59% for the hybrid catalyst with Pd/ZSM-5 and 64% for that with Cu/ZSM-5 with a similar CO conversion during the reaction. An increase in the Cu loading on ZSM-5 resulted in increasing the yield of the gasoline-ranged hydrocarbons, and in decreasing the yield of DME. Furthermore, the hybrid catalyst with Cu/ZSM-5 exhibited no deactivation for 30 h of the reaction. It was revealed that a hybrid catalyst containing Cu/ZSM-5 was efficient in the selective synthesis of gasoline-ranged hydrocarbons from syngas via methanol in the near-critical n-hexane fluid.

  10. A facile template approach for the synthesis of mesoporous Fe3C/Fe-N-doped carbon catalysts for efficient and durable oxygen reduction reaction

    Institute of Scientific and Technical Information of China (English)

    Shuai Li; Bo Li; Liang Ma; Jia Yang; Hangxun Xu

    2017-01-01

    Facile synthetic approaches toward the development of efficient and durable nonprecious metal catalysts for the oxygen reduction reaction (ORR) are very important for commercializing advanced electrochemical devices such as fuel cells and metal-air batteries.Here we report a novel template approach to synthesize mesoporous Fe-N-doped carbon catalysts encapsulated with Fe3C nanoparticles.In this approach,the layer-structured FeOCl was first used as a template for the synthesis of a three-dimensional polypyrrole (PPy) structure.During the removal of the FeOCl template,the Fe3+ can be absorbed by PPy and then converted into Fe3C nanoparticles and Fe-N-C sites during the pyrolyzing process.As a result,the as-prepared catalysts could exhibit superior electrocatalytic ORR performance to the commercial Pt/C catalyst in alkaline solutions.Furthermore,the Zn-air battery assembled using the mesoporous carbon catalyst as the air electrode could surpass the commercial Pt/C catalyst in terms of the power density and energy density.

  11. Development of Ni-Based Catalysts Derived from Hydrotalcite-Like Compounds Precursors for Synthesis Gas Production via Methane or Ethanol Reforming

    Directory of Open Access Journals (Sweden)

    Ya-Li Du

    2017-02-01

    Full Text Available As a favorably clean fuel, syngas (synthesis gas production has been the focus of concern in past decades. Substantial literatures reported the syngas production by various catalytic reforming reactions particularly in methane or ethanol reforming. Among the developed catalysts in these reforming processes, Ni-based catalysts from hydrotalcite-like compounds (HTLcs precursors have drawn considerable attention for their preferable structural traits. This review covers the recent literature reporting syngas production with Ni-based catalysts from HTLc precursors via methane or ethanol reforming. The discussion was initiated with catalyst preparation (including conventional and novel means, followed by subsequent thermal treatment processes, then composition design and the addition of promoters in these catalysts. As Ni-based catalysts have thermodynamic potential to deactivate because of carbon deposition or metal sintering, measures for dealing with these problems were finally summarized. To obtain optimal catalytic performances and resultantly better syngas production, based on analyzing the achievements of the references, some perspectives were finally proposed.

  12. Influence of Synthesis pH on Textural Properties of Carbon Xerogels as Supports for Pt/CXs Catalysts for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    C. Alegre

    2012-01-01

    Full Text Available Carbon xerogels (CXs have been prepared by polycondensation of resorcinol and formaldehyde. Two synthesis pHs were studied in order to evaluate its influence on the electrochemical behaviour of Pt catalysts supported on previous carbon xerogels, synthesized by conventional impregnation method. Catalysts were also synthesized over a commercial carbon black (Vulcan-XC-72R for comparison purposes. Characterization techniques included nitrogen physisorption, scanning electron microscopy, and X-ray diffraction. Catalysts electrochemical activity towards the oxidation of carbon monoxide and methanol was studied by cyclic voltammetry and chronoamperometry to establish the effect of the carbon support on the catalysts performance. Commercial Pt/C catalyst (E-TEK was analyzed for comparison purposes. It was observed that the more developed and mesopore-enriched porous structure of the carbon xerogel synthesized at a higher initial pH resulted in an optimal utilization of the active phase and in an enhanced and promising catalytic activity in the electrooxidation of methanol, in comparison with commercial catalysts.

  13. Synthesis of New Silicon-linked Lanthanocene Complexes and Their High Catalytic Activity for Methyl Methacrylate Polymerization with Nanometric Sodium Hydride as Co-catalyst

    Institute of Scientific and Technical Information of China (English)

    谢小敏; 黄吉玲

    2005-01-01

    The synthesis and characterization of four new silicon-linked lanthanocene complexes with pendant phenyl groups on cyclopentadiene were reported. Based on the data of elemental analyses, MS and IR, the complexes were presumed to be unsolvated and dimeric complexes [Me2Si(C5H3CMe2C6H5)2LnC1]2 [Ln=Er (1), Gd (2), Sm (3), Dy (4)]. In conjunction with AlEt3 or sodium hydride as the co-catalyst, these complexes could efficiently catalyze the polymerization of methyl methacrylate (MMA). When the nanometric sodium hydride was used as a co-catalyst, the complexes were highly effective for the polymerization of MMA. At low temperature and in short time, in [MeESi(C5H3CMe2C6H5)2LnC1]2/NaH (nanometric) system, the polymer was obtained in more than 80% yield and the molecular weight was greater than 105. The activity reached that of organolanthanide hydride as a single-component catalyst. In ]MeESi(C5H3CMe2C6H5)2ErC1]2/Nail (nanometric) system, the effects of the molar ratio of MMA/catalyst and catalyst/co-catalyst, and the temperature on polymerization were studied.

  14. Energy efficient methane tri-reforming for synthesis gas production over highly coke resistant nanocrystalline Ni–ZrO_2 catalyst

    International Nuclear Information System (INIS)

    Singha, Rajib Kumar; Shukla, Astha; Yadav, Aditya; Adak, Shubhadeep; Iqbal, Zafar; Siddiqui, Nazia; Bal, Rajaram

    2016-01-01

    Highlights: • Tri-reforming of methane is an energy efficient process to produce synthesis gas. • Nanocrystalline Ni–ZrO_2 catalyst is prepared for tri-reforming of methane. • Strong metal-support interaction is the driving force for high activity. • The process produces synthesis gas with H_2/CO ratio of around 2. • The produced synthesis gas can be used to synthesize methanol. - Abstract: We report the synthesis of nanocrystalline Ni–ZrO_2 catalyst for tri-reforming of methane (5CH_4 + O_2 + CO_2 + 2H_2O → 6CO + 12H_2) to produce synthesis gas with H_2/CO mole ratio ∼2. Nanocrystalline Ni–ZrO_2 catalyst of size between 10 and 40 nm was prepared by hydrothermal method using cetyltrimethylammonium bromide (CTAB) as a surfactant. The prepared catalysts were characterized by N_2-physisorption studies, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), temperature programmed reduction (TPR), H_2-chemisorpton, thermo-gravimetric analysis (TGA), Inductively coupled plasma atomic emission spectroscopy (ICP-AES) and X-ray photoelectron spectroscopy (XPS). The catalytic activity was monitored over temperature range between 500 and 800 °C. Different reaction parameters like temperature, Ni-loading, gas hourly space velocity (GHSV) and time on stream (TOS) were studied in detail. 4.8 wt% Ni loading for Ni–ZrO_2 catalyst was found to be the optimum Ni loading which showed the superior catalytic activity for methane tri-reforming. The catalyst was found to be stable for more than 100 h on time on stream with methane, carbon dioxide and steam conversion of ∼95% at 800 °C. The H_2/CO ratio was almost constant to 1.9 throughout the time on stream experiment. Highly dispersed nickel and the presence of strong metal support interaction were found to be the key factor for the superior activity of the catalyst. The effect of O_2 and H_2O concentration on reactant conversions and H_2/CO ratios were also

  15. Cobalt–iron nano catalysts supported on TiO{sub 2}–SiO{sub 2}: Characterization and catalytic performance in Fischer–Tropsch synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Feyzi, Mostafa, E-mail: Dalahoo2011@yahoo.com [Faculty of Chemistry, Razi University, P. O. Box: +98-67149, Kermanshah (Iran, Islamic Republic of); Yaghobi, Nakisa; Eslamimanesh, Vahid [Iran Polymer and Petrochemical Institute, P. O. Box: +98- 14965 Tehran, Iran, (Iran, Islamic Republic of)

    2015-12-15

    Graphical abstract: The Co–Fe/TiO{sub 2}–SiO{sub 2} catalysts were prepared. The prepared catalysts were tested for light olefins and C{sub 5}–C{sub 12} production. The best operational conditions are 250 °C, H{sub 2}/CO = 1/1 under 5 bar pressure. - Highlights: • The TiO{sub 2}–SiO{sub 2} supported cobalt–iron catalysts were prepared via sol–gel method. • The best operational conditions were 250 °C, GHSV = 2000 h{sup −1}, H{sub 2}/CO = 1/1 and 5 bar. • The (Co/Fe)/TiO{sub 2}–SiO{sub 2} is efficient catalyst for light olefins and C{sub 5}–C{sub 12} production. - Abstract: A series of Co–Fe catalysts supported on TiO{sub 2}–SiO{sub 2} were prepared by the sol–gel method. This research investigated the effects of (Co/Fe) wt.%, the solution pH, different Co/Fe molar ratio, calcination conditions and different promoters on the catalytic performance of cobalt–iron catalysts for the Fisher–Tropsch synthesis (FTS). It was found that the catalyst containing 35 wt.% (Co–Fe)/TiO{sub 2}–SiO{sub 2} (Co/Fe molar ratio is 80/20) promoted with 1.5 wt.% Cu and calcined in air atmosphere at 600 °C for 7 h with a heating rate of 3 °C min{sup −1} is an optimal nano catalyst for converting synthesis gas to light olefins and C{sub 5}–C{sub 12} hydrocarbons. The effects of operational conditions such as the H{sub 2}/CO ratio, gas hourly space velocity (GHSV), different reaction temperature, and reaction pressure were investigated. The results showed that the best operational conditions for optimal nano catalyst are 250 °C, GHSV = 2000 h{sup −1}, H{sub 2}/CO molar ratio 1/1 under 5 bar total pressure. Catalysts and precursors were characterized by, X-ray diffraction (XRD), scanning electron microcopy (SEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), temperature program reduction (TPR) and N{sub 2} adsorption–desorption measurements.

  16. Catalyst activity or stability: the dilemma in Pd-catalyzed polyketone synthesis.

    Science.gov (United States)

    Amoroso, Francesco; Zangrando, Ennio; Carfagna, Carla; Müller, Christian; Vogt, Dieter; Hagar, Mohamed; Ragaini, Fabio; Milani, Barbara

    2013-10-28

    A series of Pd-complexes containing nonsymmetrical bis(aryl-imino)acenaphthene (Ar-BIAN) ligands, characterized by substituents on the meta positions of the aryl rings, have been synthesized, characterized and applied in CO/vinyl arene copolymerization reactions. Crystal structures of two neutral Pd-complexes have been solved allowing comparison of the bonding properties of the ligand. Kinetic and mechanistic investigations on these complexes have been performed. The kinetic investigations indicate that in general ligands with electron-withdrawing substituents give more active, but less stable, catalytic systems, although steric effects also play a role. The good performance observed with nonsymmetrical ligands is at least in part due to a compromise between catalyst activity and lifetime, leading to a higher overall productivity with respect to catalysts based on their symmetrical counterparts. Additionally, careful analysis of the reaction profiles provided information on the catalyst deactivation pathway. The latter begins with the reduction of a Pd(II) Ar-BIAN complex to the corresponding Pd(0) species, a reaction that can be reverted by the action of benzoquinone. Then the ligand is lost, a process that appears to be facilitated by the contemporary coordination of an olefin or a CO molecule. The so formed Pd(0) complex immediately reacts with another molecule of the initial Pd(II) complex to give a Pd(I) dimeric species that irreversibly evolves to metallic palladium. Mechanistic investigations performed on the complex with a nonsymmetrical Ar-BIAN probe evidence that the detected intermediates are characterized by the Pd-C bond trans to the Pd-N bond of the aryl ring bearing electron-withdrawing substituents. In addition, the intermediate resulting from the insertion of 4-methylstyrene into the Pd-acyl bond is a five-member palladacycle and not the open-chain η(3)-allylic species observed for complexes with Ar-BIANs substituted in ortho position.

  17. Reactivity of a Carbon-Supported Single-Site Molybdenum Dioxo Catalyst for Biodiesel Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Mouat, Aidan R.; Lohr, Tracy L.; Wegener, Evan C.; Miller, Jeffrey T.; Delferro, Massimiliano; Stair, Peter C.; Marks, Tobin J.

    2016-08-23

    A single-site molybdenum dioxo catalyst, (Oc)2Mo(=O)2@C, was prepared via direct grafting of MoO2Cl2(dme) (dme = 1,2-dimethoxyethane) on high-surface- area activated carbon. The physicochemical and chemical properties of this catalyst were fully characterized by N2 physisorption, ICP-AES/OES, PXRD, STEM, XPS, XAS, temperature-programmed reduction with H2 (TPR-H2), and temperature-programmed NH3 desorption (TPD-NH3). The single-site nature of the Mo species is corroborated by XPS and TPR-H2 data, and it exhibits the lowest reported MoOx Tmax of reduction reported to date, suggesting a highly reactive MoVI center. (Oc)2Mo(=O)2@C catalyzes the transesterification of a variety of esters and triglycerides with ethanol, exhibiting high activity at moderate temperatures (60-90 °C) and with negligible deactivation. (Oc)2Mo(=O)2@C is resistant to water and can be recycled at least three times with no loss of activity. The transesterification reaction is determined experimentally to be first order in [ethanol] and first order in [Mo] with ΔH = 10.5(8) kcal mol-1 and ΔS = -32(2) eu. The low energy of activation is consistent with the moderate conditions needed to achieve rapid turnover. This highly active carbon-supported single-site molybdenum dioxo species is thus an efficient, robust, and lowcost catalyst with significant potential for transesterification processes.

  18. Hierarchical zeolites: progress on synthesis and characterization of mesoporous zeolite single crystal catalysts

    DEFF Research Database (Denmark)

    Kustova, Marina; Egeblad, Kresten; Christensen, Claus H.

    2007-01-01

    Recently, a new family of crystalline zeolitic materials was reported, the so-called mesoporous zeolite single crystals featuring individual zeolite single crystals with an additional noncrystalline mesopore system interconnected with the usual micropore system of the zeolite, resulting...... measurements. Additionally, the results of diffusion of n-hexadecane in conventional and mesoporous zeolites are presented. Isomerization and cracking of n-hexadecane was chosen as model test reaction for these materials. All results support that mesoporous zeolites are superior catalysts due to improved mass...... transport. Importantly, the mesoporous zeolites show significant improved resistance to poisoning by carbon formation....

  19. Synthesis, characterization and optimization of platinum-alloy nanoparticle catalysts in proton exchange membrane fuel cells

    Science.gov (United States)

    Srivastava, Ratndeep

    Renewable hydrogen-fuelled proton exchange membrane (PEMFC) fuel cells have consistently demonstrated great promise as a future source of energy due to their high conversion efficiency, lower temperature of operation and lack of greenhouse emissions. One of the major impediments in the commercialization of polymer electrolyte membrane fuel cells is the insufficient catalytic reactivity and higher cost of Pt electrocatalysts which are utilized for the electroreduction of oxygen from air. This dissertation focuses primarily on a family of Pt alloy fuel cell electrocatalysts referred to as de-alloyed core-shell electrocatalysts. These materials are bimetallic or multimetallic nanoparticles, mostly supported on conductive supports which were first described in a dissertation by Dr. S. Koh earlier in 2009.1 De-alloyed Pt nanoparticle electrocatalysts are formed from base metal rich binary Pt-M and ternary Pt-M1-M 2 (M, M1, M2 = Cu, Co, Ni, Fe and Cr) alloy nanoparticle precursors. The precursors are transformed and activated by electrochemical selective dissolution of the less noble metal component of the precursors (de-alloying). They have shown exceptional activity for oxygen reduction reaction (ORR) in idealized electrochemical half cell measurements, in particular rotating disk electrode experiments. However, these materials were never tested or implemented in realistic Membrane Electrode Assemblies (MEA) and single PEM fuel cells. The objective of this work was to implement de-alloyed Pt particle catalysts in realistic fuel cell electrode layers as well as a detailed characterization of their behavior and stability. The major challenges of MEA implementation consists of the behavior of the new nanostructured electrocatalysts inside the complex three-phase interface of polymer membrane ionomer, liquid water, metal catalyst, support, and reactant gas. Activity measurements were followed by medium and long-term durability analysis by potential cycling of the membrane

  20. Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

    Directory of Open Access Journals (Sweden)

    Maurizio Selva

    2016-08-01

    Full Text Available The use of ionic liquids (ILs as organocatalysts is reviewed for transesterification reactions, specifically for the conversion of nontoxic compounds such as dialkyl carbonates to both linear mono-transesterification products or alkylene carbonates. An introductory survey compares pros and cons of classic catalysts based on both acidic and basic systems, to ionic liquids. Then, innovative green syntheses of task-specific ILs and their representative applications are introduced to detail the efficiency and highly selective outcome of ILs-catalyzed transesterification reactions. A mechanistic hypothesis is discussed by the concept of cooperative catalysis based on the dual (electrophilic/nucleophilic activation of reactants.

  1. One-pot synthesis of Au@SiO2 catalysts: A click chemistry approach

    KAUST Repository

    Solovyeva, Vera A.

    2014-10-13

    Using the copper-catalyzed azide-alkyne cycloaddition "click" reaction, a library of triazole amphiphiles with a variety of functional polar "heads" and hydrophobic or superhydrophobic "tails" was synthesized. The amphiphiles were evaluated for their ability to stabilize small Au nanoparticles, and, at the same time, serve as templates for nanocasting porous SiO2. One of the Au@SiO2 materials thus prepared was found to be a highly active catalyst for the Au nanoparticle-catalyzed regioselective hydroamination of alkynes.

  2. One-pot synthesis of Au@SiO2 catalysts: A click chemistry approach

    KAUST Repository

    Solovyeva, Vera A.; Vu, Khanh B.; Merican, Zulkifli; Sougrat, Rachid; Rodionov, Valentin O.

    2014-01-01

    Using the copper-catalyzed azide-alkyne cycloaddition "click" reaction, a library of triazole amphiphiles with a variety of functional polar "heads" and hydrophobic or superhydrophobic "tails" was synthesized. The amphiphiles were evaluated for their ability to stabilize small Au nanoparticles, and, at the same time, serve as templates for nanocasting porous SiO2. One of the Au@SiO2 materials thus prepared was found to be a highly active catalyst for the Au nanoparticle-catalyzed regioselective hydroamination of alkynes.

  3. A facile synthesis of phenazine and quinoxaline derivatives using magnesium sulfate heptahydrate as a catalyst

    Directory of Open Access Journals (Sweden)

    BAHADOR KARAMI

    2011-09-01

    Full Text Available Convenient and simple procedures for the synthesis of phenazine and quinoxaline derivatives were developed via a reaction of o-phenylenediamines and 1,2-dicarbonyl compounds. In addition, the synthesis of two new 1,4-benzodiazine derivatives and the catalytic activity of magnesium sulfate heptahydrate (MgSO4·7H2O in the room temperature condensation of o-phenylenediamines and 1,2-dicarbonyl compounds in ethanol as solvent are reported. This method has many appealing attributes, such as excellent yields, short reaction times, and simple work-up procedures.

  4. Are Diatoms “Green” Aluminosilicate Synthesis Microreactors for Future Catalyst Production?

    Directory of Open Access Journals (Sweden)

    Lydia Köhler

    2017-12-01

    Full Text Available Diatom biosilica may offer an interesting perspective in the search for sustainable solutions meeting the high demand for heterogeneous catalysts. Diatomaceous earth (diatomite, i.e., fossilized diatoms, is already used as adsorbent and carrier material. While diatomite is abundant and inexpensive, freshly harvested and cleaned diatom cell walls have other advantages, with respect to purity and uniformity. The present paper demonstrates an approach to modify diatoms both in vivo and in vitro to produce a porous aluminosilicate that is serving as a potential source for sustainable catalyst production. The obtained material was characterized at various processing stages with respect to morphology, elemental composition, surface area, and acidity. The cell walls appeared normal without morphological changes, while their aluminum content was raised from the molar ratio n(Al:n(Si 1:600 up to 1:50. A specific surface area of 55 m2/g was measured. The acidity of the material increased from 149 to 320 µmol NH3/g by ion exchange, as determined by NH3 TPD. Finally, the biosilica was examined by an acid catalyzed test reaction, the alkylation of benzene. While the cleaned cell walls did not catalyze the reaction at all, and the ion exchanged material was catalytically active. This demonstrates that modified biosilica does indeed has potential as a basis for future catalytically active materials.

  5. Synthesis of carbon-supported nickel catalysts for the dry reforming of CH{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Fidalgo, B.; Zubizarreta, L.; Bermudez, J.M.; Arenillas, A.; Menendez, J.A. [Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain)

    2010-07-15

    A series of carbon-based nickel (Ni) catalysts was prepared in order to investigate the effect of the preparation method on the dispersion of Ni and its final catalytic activity in the dry reforming of methane, i.e. CH{sub 4} + CO{sub 2} 2H{sub 2} + 2CO. Three parameters were studied: (i) the influence of the surface chemistry of the carbon used as support; (ii) the method of drying (conventional vs. microwave drying); and, (iii) the temperature of the reduction stage. In order to study the role of the surface chemistry of the commercial activated carbon used as support, the active carbon was tested as received and oxidized. Although a better Ni dispersion was achieved over the oxidized support, the conversions were much lower. It was also found that microwave drying offers various advantages over conventional drying, the main one being that less time is required to prepare the catalyst. Two reduction temperatures were used (300 and 500 C), being found that it is necessary to adjust this parameter to prevent the Ni particles from sintering. (author)

  6. Flame synthesis of carbon nano onions using liquefied petroleum gas without catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Dhand, Vivek, E-mail: vivekdhand2012@gmail.com [Centre for Knowledge Management of Nanoscience and Technology, 12-5-32/8, Vijayapuri Colony, Tarnaka, Secunderabad-500 017, A.P (India); Prasad, J. Sarada; Rao, M. Venkateswara [Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University, Kukatpally, Hyderabad 500 085 (India); Bharadwaj, S. [Department of Physics, CVR College of Engineering and Osmania University, Hyderabad 501510, A.P (India); Anjaneyulu, Y. [TLGVRC, Jackson State University, JSU Box 18739, Jackson, MS 39217-0939 (United States); Jain, Pawan Kumar [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur PO, Hyderabad 500005, Andhra Pradesh (India)

    2013-03-01

    Densely agglomerated, high specific surface area carbon nano onions with diameter of 30-40 nm have been synthesized. Liquefied petroleum gas and air mixtures produced carbon nano onions in diffusion flames without catalyst. The optimized oxidant to fuel ratio which produces carbon nano onions has been found to be 0.1 slpm/slpm. The experiment yielded 70% pure carbon nano onions with a rate of 5 g/h. X-ray diffraction, high-resolution electron microscopy and Raman spectrum reveal the densely packed sp{sup 2} hybridized carbon with (002) semi-crystalline hexagonal graphite reflection. The carbon nano onions are thermally stable up to 600 Degree-Sign C. - Highlights: Black-Right-Pointing-Pointer Flame synthesized carbon nano onions with 30-40 nm diameters. Black-Right-Pointing-Pointer LPG/air, diffusion type flame used in absence of catalyst to produce nano onions. Black-Right-Pointing-Pointer Carbon nano onion production rate is 5 g/hr and with 70% purity.

  7. Synthesis of triazole-based and imidazole-based zinc catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Valdez, Carlos A.; Satcher, Jr., Joe H.; Aines, Roger D.; Baker, Sarah E.

    2013-03-12

    Various methods and structures of complexes and molecules are described herein related to a zinc-centered catalyst for removing carbon dioxide from atmospheric or aqueous environments. According to one embodiment, a method for creating a tris(triazolyl)pentaerythritol molecule includes contacting a pentaerythritol molecule with a propargyl halide molecule to create a trialkyne molecule, and contacting the trialkyne molecule with an azide molecule to create the tris(triazolyl)pentaerythritol molecule. In another embodiment, a method for creating a tris(imidazolyl)pentaerythritol molecule includes alkylating an imidazole 2-carbaldehyde molecule to create a monoalkylated aldehyde molecule, reducing the monoalkylated aldehyde molecule to create an alcohol molecule, converting the alcohol molecule to create an alkyl halide molecule using thionyl halide, and reacting the alkyl halide molecule with a pentaerythritol molecule to create a tris(imidazolyl)pentaerythritol molecule. In another embodiment, zinc is bound to the tris(triazolyl)pentaerythritol molecule to create a zinc-centered tris(triazolyl)pentaerythritol catalyst for removing carbon dioxide from atmospheric or aqueous environments.

  8. Large-scale synthesis of coiled-like shaped carbon nanotubes using bi-metal catalyst

    Science.gov (United States)

    Krishna, Vemula Mohana; Somanathan, T.; Manikandan, E.; Umar, Ahmad; Maaza, M.

    2018-02-01

    Carbon nanomaterials (CNMs), especially carbon nanotubes (CNTs) with coiled structure exhibit scientifically fascinating. They may be projected as an innovative preference to future technological materials. Coiled carbon nanotubes (c-CNTs) on a large-scale were successfully synthesized with the help of bi-metal substituted α-alumina nanoparticles catalyst via chemical vapor deposition (CVD) technique. Highly spring-like carbon nanostructures were observed by field emission scanning electron microscope (FESEM) examination. Furthermore, the obtained material has high purity, which correlates the X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) analysis. Raman spectroscopy reveals that the carbon multi layers are well graphitized and crystalline, even if they have defects in its structure due to coiled morphology. High-resolution transmission electron microscope (HRTEM) describes internal structure and dia of the product. Ultimately, results support the activity of bi-metal impregnated α-alumina nanoparticles catalyst to determine the high yield, graphitization and internal structure of the material. We have also studied the purified c-CNTs magnetic properties at room temperature and will be an added advantage in several applications.

  9. A heterogeneous Pd-Bi/C catalyst in the synthesis of L-lyxose and L-ribose from naturally occurring D-sugars.

    Science.gov (United States)

    Fan, Ao; Jaenicke, Stephan; Chuah, Gaik-Khuan

    2011-10-26

    A critical step in the synthesis of the rare sugars, L-lyxose and L-ribose, from the corresponding D-sugars is the oxidation to the lactone. Instead of conventional oxidizing agents like bromine or pyridinium dichromate, it was found that a heterogeneous catalyst, Pd-Bi/C, could be used for the direct oxidation with molecular oxygen. The composition of the catalyst was optimized and the best results were obtained with 5 : 1 atomic ratio of Pd : Bi. The overall yields of the five-step procedure to L-ribose and L-lyxose were 47% and 50%, respectively. The synthetic procedure is advantageous from the viewpoint of overall yield, reduced number of steps, and mild reaction conditions. Furthermore, the heterogeneous oxidation catalyst can be easily separated from the reaction mixture and reused with no loss of activity.

  10. Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

    Directory of Open Access Journals (Sweden)

    Sudipta Pathak

    2013-11-01

    Full Text Available A convenient and efficient methodology for the synthesis of densely substituted pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused isocoumarins were formed in good yields. This synthetic method has several advantages such as the employment of solvent-free reaction conditions without the use of any toxic reagents and metal catalysts, the ease of product isolation, the use of a recyclable catalyst, the low cost, the easy availability of the starting materials, and the excellent yields of products.

  11. Production of carbon nanotubes: Chemical vapor deposition synthesis from liquefied petroleum gas over Fe-Co-Mo tri-metallic catalyst supported on MgO

    Energy Technology Data Exchange (ETDEWEB)

    Setyopratomo, P., E-mail: puguh-sptm@yahoo.com; Wulan, Praswasti P. D. K., E-mail: wulanmakmur@gmail.com; Sudibandriyo, M., E-mail: msudib@che.ui.ac.id [Chemical Engineering Department, University of Indonesia, Depok Campus, Depok 16424 (Indonesia)

    2016-06-03

    Carbon nanotubes were produced by chemical vapor deposition method to meet the specifications for hydrogen storage. So far, the various catalyst had been studied outlining their activities, performances, and efficiencies. In this work, tri-metallic catalyst consist of Fe-Co-Mo supported on MgO was used. The catalyst was prepared by wet-impregnation method. Liquefied Petroleum Gas (LPG) was used as carbon source. The synthesis was conducted in atmospheric fixed bed reactor at reaction temperature range 750 – 850 °C for 30 minutes. The impregnation method applied in this study successfully deposed metal component on the MgO support surface. It found that the deposited metal components might partially replace Mg(OH){sub 2} or MgO molecules in their crystal lattice. Compare to the original MgO powder; it was significant increases in pore volume and surface area has occurred during catalyst preparation stages. The size of obtained carbon nanotubes is ranging from about 10.83 nm OD/4.09 nm ID up to 21.84 nm OD/6.51 nm ID, which means that multiwall carbon nanotubes were formed during the synthesis. Yield as much as 2.35 g.CNT/g.catalyst was obtained during 30 minutes synthesis and correspond to carbon nanotubes growth rate of 0.2 μm/min. The BET surface area of the obtained carbon nanotubes is 181.13 m{sup 2}/g and around 50 % of which is contributed by mesopores. Micropore with half pore width less than 1 nm contribute about 10% volume of total micro and mesopores volume of the carbon nanotubes. The existence of these micropores is very important to increase the hydrogen storage capacity of the carbon nanotubes.

  12. LaCl 3. 7H 2 O: An efficient catalyst for the synthesis of phosphinates ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 126; Issue 1 ... Abstract. An expeditious neat procedure was developed for the synthesis of a series of new methyl phenyl heterocyclic phosphinates (3a-l) through Michaelis-Arbuzov reaction by the reaction of various heterocyclic halides (Cl or Br) (1a-l) with dimethyl ...

  13. CaO as Drop-In Colloidal Catalysts for the Synthesis of Higher Polyglycerols

    NARCIS (Netherlands)

    Kirby, Fiona; Nieuwelink, Anne Eva; Kuipers, Bonny W M; Kaiser, Anton; Bruijnincx, Pieter C A; Weckhuysen, Bert M.

    2015-01-01

    Glycerol is an attractive renewable building block for the synthesis of polyglycerols, which find application in the cosmetic and pharmaceutical industries. The selective etherification of glycerol to higher oligomers was studied in the presence of CaO colloids and the data are compared with those

  14. Synthesis of PD particles by alcohols-assisted photoreduction for use in supported catalysts

    Science.gov (United States)

    Burton, Patrick David; Boyle, Timothy J; Datye, Abhaya

    2015-02-24

    The present disclosure provides a novel synthesis method for palladium nanoparticles and palladium nanoparticles made using the method. The nanoparticles resulting from the method are highly reactive and, when deposited on a support, are highly suitable for use as catalytic material.

  15. Gram-Scale Synthesis of Highly Active and Durable Octahedral PtNi Nanoparticle Catalysts for Proton Exchange Membrane Fuel Cell

    DEFF Research Database (Denmark)

    Choi, Juhyuk; Jang, Jue-Hyuk; Roh, Chi-Woo

    2018-01-01

    for the commercialization of PEMFCs. In this study, we focus on gram-scale synthesis of octahedral PtNi nanoparticles with Pt overlayers (PtNi@Pt) supported on the carbon, resulting in enhanced catalytic activity and durability. Such PtNi@Pt catalysts show high mass activity (1.24 A mgPt−1) at 0.9 V (vs RHE) for the ORR......Proton exchange membrane fuel cells (PEMFC) are regarded as a promising renewable energy source for a future hydrogen energy society. However, highly active and durable catalysts are required for the PEMFCs because of their intrinsic high overpotential at the cathode and operation under the acidic...... condition for oxygen reduction reaction (ORR). Since the discovery of the exceptionally high surface activity of Pt3Ni(111), the octahedral PtNi nanoparticles have been synthesized and tested. Nonetheless, their milligram-scale synthesis method and poor durability make them unsuitable...

  16. Chiral gold(I vs chiral silver complexes as catalysts for the enantioselective synthesis of the second generation GSK-hepatitis C virus inhibitor

    Directory of Open Access Journals (Sweden)

    María Martín-Rodríguez

    2011-07-01

    Full Text Available The synthesis of a GSK 2nd generation inhibitor of the hepatitis C virus, by enantioselective 1,3-dipolar cycloaddition between a leucine derived iminoester and tert-butyl acrylate, was studied. The comparison between silver(I and gold(I catalysts in this reaction was established by working with chiral phosphoramidites or with chiral BINAP. The best reaction conditions were used for the total synthesis of the hepatitis C virus inhibitor by a four step procedure affording this product in 99% ee and in 63% overall yield. The origin of the enantioselectivity of the chiral gold(I catalyst was justified according to DFT calculations, the stabilizing coulombic interaction between the nitrogen atom of the thiazole moiety and one of the gold atoms being crucial.

  17. Alloy catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel alloy catalyst material for use in the synthesis of hydrogen peroxide from oxygen and hydrogen, or from oxygen and water. The present invention also relates to a cathode and an electrochemical cell comprising the novel catalyst material, and the process use...... of the novel catalyst material for synthesising hydrogen peroxide from oxygen and hydrogen, or from oxygen and water....

  18. Synthesis and characterization of group V metal carbide and nitride catalysts

    Science.gov (United States)

    Kwon, Heock-Hoi

    1998-11-01

    Group V transition metal carbides and nitrides were prepared via the temperature programmed reaction (TPR) of corresponding oxides with NHsb3 or a CHsb4/Hsb2 mixture. Except for the tantalum compounds, phase-pure carbides and nitrides were prepared. The vanadium carbides and nitrides were the most active and selective catalysts. Therefore the principal focus of the research was the preparation, characterization, and evaluation of high surface area vanadium nitride catalysts. A series of vanadium nitrides with surface areas up to 60 msp2/g was prepared. Thermal gravimetric analysis coupled with x-ray diffraction and scanning electron microscopy indicated that the solid-state reaction proceeded by the sequential reduction of Vsb2Osb5 to VOsb{0.9} and concluded with the topotactic substitution of nitrogen for oxygen in VOsb{0.9}. The transformation of Vsb2Osb5 to VN was pseudomorphic. An experimental design was executed to determine effects of the heating rates and space velocities on the VN microstructures. The heating rates had minor effects on the surface areas and pore size distributions; however, increasing the space velocity significantly increased the surface area. The materials were mostly mesoporous. Oxygen chemisorption on the vanadium nitrides scaled linearly with the surface area. The corresponding O/Vsbsurface ratio was ≈0.6. The vanadium nitrides were active for butane activation and pyridine hydrodenitrogenation. During butane activation, their selectivities towards dehydrogenation products were as high as 98%. The major product in pyridine hydrodenitrogenation was pentane. The reaction rates increased almost linearly with the surface area suggesting that these reactions were structure insensitive. The vanadium nitrides were not active for crotonaldehyde hydrogenation; however, they catalyzed an interesting ring formation reaction that produced methylbenzaldehyde and xylene from crotonaldehyde. A new method was demonstrated for the production of very

  19. Zinc (II) [tetra(4-methylphenyl)] Porphyrin: a Novel and Reusable Catalyst for Efficient Synthesis of 2,4,5-trisubstituted Imidazoles Under Ultrasound Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Safari, Javad; Khalili, Shiva Dehghan; Banitaba, Sayed Hossein; Dehghani, Hossein [Univ. of Kashan, Kashan (Iran, Islamic Republic of)

    2011-10-15

    An efficient three-component one-step synthesis of 2,4,5-trisubstituted imidazoles by condensation reaction of 1,2-diketones or α-hydroxyketones with aromatic aldehydes and ammonium acetate using Zinc (II) [tetra (4-methylphenyl)] porphyrin as a novel and reusable catalyst under ultrasound irradiation at ambient temperature is described. In this method, α-hydroxyketones as well as 1,2-diketones were converted to their corresponding 2,4,5-trisubstituted imidazoles in excellent yields.

  20. Synthesis and nature of heterogeneous catalysts of low-valent tungsten supported on alumina

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, A.; Hucul, D.A.

    1980-01-01

    Temperature-programed decomposition of catalysts prepared from zero-valent W(CO)/sub 6/ and alumina under rigorously air-free conditions showed a low-temperature carbon monoxide desorption peak at 110/sup 0/-172/sup 0/C, depending on alumina pretreatment, in which a relatively stable surface W(CO)/sub 3/ complex was formed; and a high-temperature carbon monoxide desorption peak at 257/sup 0/ to > 400/sup 0/C, which gave zero-valent tungsten if the ratio of hydroxyl groups of alumina to tungsten surface complexes was low, and hexavalent tungsten if the ratio was high. Up to about half the W(CO)/sub 6/ sublimated from the alumina during activation.

  1. Electro-synthesis of novel nanostructured PEDOT films and their application as catalyst support

    Directory of Open Access Journals (Sweden)

    Yan Yushan

    2011-01-01

    Full Text Available Abstract Poly(3,4-ethylenedioxythiophene (PEDOT films doped with nitric and chlorine ions have been electrochemically deposited simply by a one-step electrochemical method in an aqueous media in the absence of any surfactant. The fabricated PEDOT films were characterized by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The results indicate that the hierarchical structured PEDOT film doped with nitric ions displays a 'lunar craters' porous morphology consisting of PEDOT nano-sheets with a thickness of less than 2 nm. The effect of counter ions on the electro-polymerization, the electrochemistry, and the morphology of the polymer film was studied. Compared with PEDOT film doped with nitric acid, PEDOT film deposited in the presence of chlorine ions shows irregular morphology and less electrochemical activity. The specific nanostructure of the polymer was further studied as catalyst support for platinum nanoparticles to methanol electro-oxidation.

  2. Light olefins from synthesis gas using ruthenium on rare earth oxide catalysts

    International Nuclear Information System (INIS)

    Bruce, L.; Hardin, S.; Hoang, M.; Turney, T.

    1988-01-01

    The interaction of ruthenium carbonyl, Ru/sub 3/(CO)/sub 12/ with rare earth oxides of high surface area, >50m/sup 2/g/sup -1/, has been studied. [Ru/sub 3/(μ H)(CO)/sub 10/(μ-OM=)] is formed on holmia, but on lanthana only [Ru(CO)/sub 2/]/sub n/ species are observed. Reduction of the carbonyl ligands takes place at <573K to give catalysts for the hydrogenation of carbon monoxide with activity and selectivity dependent on the particular rare earth oxide and pretreatment. Over ceria, the product is up to 55 wt% C2-5 olefins. A similar selectivity is obtained over lanthana only after redispersion through a reduction-oxidation-reduction cycle

  3. Green synthesis of Ni-Nb oxide catalysts for low-temperature oxidative dehydrogenation of ethane

    KAUST Repository

    Zhu, Haibo

    2015-03-05

    The straightforward solid-state grinding of a mixture of Ni nitrate and Nb oxalate crystals led to, after mild calcination (T<400°C), nanostructured Ni-Nb oxide composites. These new materials efficiently catalyzed the oxidative dehydrogenation (ODH) of ethane to ethylene at a relatively low temperature (T<300°C). These catalysts appear to be much more stable than the corresponding composites prepared by other chemical methods; more than 90% of their original intrinsic activity was retained after 50h with time on-stream. Furthermore, the stability was much less affected by the Nb content than in composites prepared by classical "wet" syntheses. These materials, obtained in a solvent-free way, are thus promising green and sustainable alternatives to the current Ni-Nb candidates for the low-temperature ODH of ethane.

  4. Controllable synthesis of metal selenide heterostructures mediated by Ag2Se nanocrystals acting as catalysts

    Science.gov (United States)

    Zhou, Jiangcong; Huang, Feng; Xu, Ju; Wang, Yuansheng

    2013-09-01

    Ag2Se nanocrystals were demonstrated to be novel semiconductor mediators, or in other word catalysts, for the growth of semiconductor heterostructures in solution. This is a result of the unique feature of Ag2Se as a fast ion conductor, allowing foreign cations to dissolve and then to heterogrow the second phase. Using Ag2Se nanocrystals as catalysts, dimeric metal selenide heterostructures such as Ag2Se-CdSe and Ag2Se-ZnSe, and even multi-segment heterostructures such as Ag2Se-CdSe-ZnSe and Ag2Se-ZnSe-CdSe, were successfully synthesized. Several interesting features were found in the Ag2Se based heterogrowth. At the initial stage of heterogrowth, a layer of the second phase forms on the surface of an Ag2Se nanosphere, with a curved junction interface between the two phases. With further growth of the second phase, the Ag2Se nanosphere tends to flatten the junction surface by modifying its shape from sphere to hemisphere in order to minimize the conjunct area and thus the interfacial energy. Notably, the crystallographic relationship of the two phases in the heterostructure varies with the lattice parameters of the second phase, in order to reduce the lattice mismatch at the interface. Furthermore, a small lattice mismatch at the interface results in a straight rod-like second phase, while a large lattice mismatch would induce a tortuous product. The reported results may provide a new route for developing novel selenide semiconductor heterostructures which are potentially applicable in optoelectronic, biomedical, photovoltaic and catalytic fields.Ag2Se nanocrystals were demonstrated to be novel semiconductor mediators, or in other word catalysts, for the growth of semiconductor heterostructures in solution. This is a result of the unique feature of Ag2Se as a fast ion conductor, allowing foreign cations to dissolve and then to heterogrow the second phase. Using Ag2Se nanocrystals as catalysts, dimeric metal selenide heterostructures such as Ag2Se-CdSe and Ag2Se

  5. Synthesis and characterization of new chiral ketopinic acid-derived catalysts immobilized on polystyrene-bound imidazole

    Directory of Open Access Journals (Sweden)

    Hassan Yusuf

    2017-02-01

    Full Text Available Four new chiral ketopinic acid-derived catalysts were anchored on a polystyrene-bound imidazole via non-covalent bond. The resulting heterogeneous catalysts were successfully characterized using IR, SEM, and TGA analyses.

  6. Final Technical Report for GO15052 Intematix: Combinatorial Synthesis and High Throughput Screening of Effective Catalysts for Chemical Hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Melman, Jonathan [Intematix Corporation, Fremont, CA (United States)

    2017-02-22

    The objectives of this project are: to discover cost-effective catalysts for release of hydrogen from chemical hydrogen storage systems; and to discover cost-effective catalysts for the regeneration of spent chemical hydrogen storage materials.

  7. Synthesis of biodiesel from waste vegetable oil with large amounts of free fatty acids using a carbon-based solid acid catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Qing; Gao, Jixian; Nawaz, Zeeshan; Liao, Yuhui; Wang, Dezheng; Wang, Jinfu [Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)

    2010-08-15

    A carbon-based solid acid catalyst was prepared by the sulfonation of carbonized vegetable oil asphalt. This catalyst was employed to simultaneously catalyze esterification and transesterification to synthesis biodiesel when a waste vegetable oil with large amounts of free fatty acids (FFAs) was used as feedstock. The physical and chemical properties of this catalyst were characterized by a variety of techniques. The maximum conversion of triglyceride and FFA reached 80.5 wt.% and 94.8 wt.% after 4.5 h at 220 C, when using a 16.8 M ratio of methanol to oil and 0.2 wt.% of catalyst to oil. The high catalytic activity and stability of this catalyst was related to its high acid site density (-OH, Broensted acid sites), hydrophobicity that prevented the hydration of -OH species, hydrophilic functional groups (-SO{sub 3}H) that gave improved accessibility of methanol to the triglyceride and FFAs, and large pores that provided more acid sites for the reactants. (author)

  8. Synthesis of mesoporous zeolite catalysts by in situ formation of carbon template over nickel nanoparticles

    DEFF Research Database (Denmark)

    Abildstrøm, Jacob Oskar; Kegnæs, Marina; Hytoft, Glen

    2016-01-01

    A novel synthesis procedure for the preparation of the hierarchical zeolite materials with MFI structure based on the carbon templating method with in situ generated carbon template is presented in this study. Through chemical vapour deposition of coke on nickel nanoparticles supported on silica...... oxide, a carbon-silica composite is obtained and exploited as a combined carbon template/silica source for zeolite synthesis. This approach has several advantages in comparison with conventional carbon templating methods, where relatively complicated preparative strategies involving multistep...... impregnation procedures and rather expensive chemicals are used. Removal of the carbon template by combustion results in zeolite single crystals with intracrystalline pore volumes between 0.28 and 0.48 cm3/g. The prepared zeolites are characterized by XRD, SEM, TEM and physisorption analysis. The isomerization...

  9. A comparative study on the influence of the platinum catalyst in poly(dimethylsiloxane) based networks synthesis

    DEFF Research Database (Denmark)

    Bejenariu, Anca Gabriela; Poulsen, Julie Øblom; Skov, Anne Ladegaard

    2009-01-01

    The aim of the project is to find the best of three Pt catalysts and their appropriate quantity in order to obtain soft networks in one hour at room temperature. How the choice of catalyst influences the final elastomeric properties is also evaluated. The differences between the catalysts...

  10. Evaluation of palm oil mill fly ash supported calcium oxide as a heterogeneous base catalyst in biodiesel synthesis from crude palm oil

    International Nuclear Information System (INIS)

    Ho, Wilson Wei Sheng; Ng, Hoon Kiat; Gan, Suyin; Tan, Sang Huey

    2014-01-01

    Highlights: • Calcination temperature is an important influencing factor in catalytic activity. • The optimum calcination conditions were determined to be 850 °C for 2 h. • Maximum yield of 79.8% and FAME conversion of 97.1% was achieved. • Kinetic data fitted the pseudo-first order model and the E a was 42.56 kJ mol −1 . • The novel catalyst can be reused for 3 cycles with a final biodiesel yield of 60%. - Abstract: A palm oil mill fly ash supported calcium oxide (CaO) catalyst was developed to be used as a heterogeneous base catalyst in biodiesel synthesis from crude palm oil (CPO). The catalyst preparation procedure was optimised in terms of final calcination temperature and duration. The optimum catalyst preparation conditions were determined as final calcination at 850 °C for 2 h with 45 wt.% loading of calcined calcium carbonate (CaCO 3 ). A maximum biodiesel yield of 75.73% was achieved for this catalyst under fixed transesterification conditions. Characterisation tests showed that the catalyst had higher surface area and basic sites which favoured transesterification. The effects of catalyst loading, methanol to oil molar ratio, reaction temperature and reaction time on biodiesel yield and fatty acid methyl ester (FAME) conversion were also investigated. It was determined that transesterification conditions of 6 wt.% catalyst loading, 12:1 methanol to oil molar ratio, 45 °C reaction temperature, 3 h reaction time and 700 rpm stirring speed resulted in biodiesel yield and FAME conversion of 79.76% and 97.09%, respectively. Experimental kinetic data obtained from the heterogeneous transesterification reactions fitted the pseudo-first order kinetic model. The activation energy (E a ) of the reaction was calculated to be 42.56 kJ mol −1 . Key physicochemical properties of the produced biodiesel were measured and found to be within the limits set by EN 14214. The developed catalyst could feasibly be used up to three consecutive cycles after

  11. Synthesis of Fe3O4/Pt Nanoparticles Decorated Carbon Nanotubes and Their Use as Magnetically Recyclable Catalysts

    Directory of Open Access Journals (Sweden)

    Hongkun He

    2011-01-01

    Full Text Available We report a facile approach to prepare Fe3O4/Pt nanoparticles decorated carbon nanotubes (CNTs. The superparamagnetic Fe3O4 nanoparticles with average size of 4∼5 nm were loaded on the surfaces of carboxyl groups functionalized CNTs via a high-temperature solution-phase hydrolysis method from the raw material of FeCl3. The synthesis process of magnetic CNTs is green and readily scalable. The loading amounts of Fe3O4 nanopartilces and the magnetizations of the resulting magnetic CNTs show good tunability. The Pt nanopaticles with average size of 2.5 nm were deposited on the magnetic CNTs through a solution-based method. It is demonstrated that the Fe3O4/Pt nanoparticles decorated CNTs have high catalytic activity in the reduction reaction of 4-nitrophenol and can be readily recycled by a magnet and reused in the next reactions with high efficiencies for at least fifteen successive cycles. The novel CNTs-supported magnetically recyclable catalysts are promising in heterogeneous catalysis applications.

  12. Synthesis of Fe3O4/Pt Nanoparticles Decorated Carbon Nano tubes and Their Use as Magnetically Recyclable Catalysts

    International Nuclear Information System (INIS)

    He, H.; Gao, C.

    2011-01-01

    We report a facile approach to prepare Fe 3 O 4 /Pt nanoparticles decorated carbon nano tubes (CNTs). The superparamagnetic Fe 3 O 4 nanoparticles with average size of 45 nm were loaded on the surfaces of carboxyl groups functionalized CNTs via a high-temperature solution-phase hydrolysis method from the raw material of FeCl 3 . The synthesis process of magnetic CNTs is green and readily scalable. The loading amounts of Fe 3 O 4 nanoparticles and the magnetizations of the resulting magnetic CNTs show good tunability. The Pt nanoparticles with average size of 2.5 nm were deposited on the magnetic CNTs through a solution-based method. It is demonstrated that the Fe 3 O 4 /Pt nanoparticles decorated CNTs have high catalytic activity in the reduction reaction of 4-nitrophenol and can be readily recycled by a magnet and reused in the next reactions with high efficiencies for at least fifteen successive cycles. The novel CNTs-supported magnetically recyclable catalysts are promising in heterogeneous catalysis applications.

  13. Ball Milling Assisted Solvent and Catalyst Free Synthesis of Benzimidazoles and Their Derivatives.

    Science.gov (United States)

    El-Sayed, Taghreed H; Aboelnaga, Asmaa; Hagar, Mohamed

    2016-08-24

    Benzoic acid and o-phenylenediamine efficiently reacted under the green solvent-free Ball Milling method. Several reaction parameters were investigated such as rotation frequency; milling balls weight and milling time. The optimum reaction condition was milling with 56.6 g weight of balls at 20 Hz frequency for one hour milling time. The study was extended for synthesis of a series of benzimidazol-2-one or benzimidazol-2-thione using different aldehydes; carboxylic acids; urea; thiourea or ammonium thiocyanate with o-phenylenediamine. Moreover; the alkylation of benzimidazolone or benzimidazolthione using ethyl chloroacetate was also studied.

  14. On the mechanism of electrochemical ammonia synthesis on the Ru catalyst.

    Science.gov (United States)

    Back, Seoin; Jung, Yousung

    2016-04-07

    We theoretically investigate the electrochemical N2 reduction reaction (NRR) mechanism to produce NH3 on the Ru catalyst. All possible N-N dissociation steps during the reduction processes were evaluated along with the conventional associative and dissociative pathways. Based on the calculated free energy diagrams, it is revealed that the kinetically facile intermediate dissociative pathways during the NRR require a thermodynamic limiting potential (-0.71 V) similar to the associative pathway (-0.68 V), although the initial dissociative pathway as in the Haber-Bosch process has a substantial kinetic barrier for the N-N bond dissociation. The competitive hydrogen evolution is found to be a major hurdle for achieving a high efficiency for the electrochemical nitrogen reduction. In the low overpotential region, the hydrogen adsorption is thermodynamically more favorable than the protonation of N2, thereby reducing the number of active sites for the N2 activation. A comparison of free energies in the presence of different H-coverages on the Ru further demonstrates that the H-coverage can significantly increase the energy barrier for the first protonation of N2, resulting in a change of the potential determining step and an increase in the overpotentials.

  15. Synthesis of nanostructured catalysts based on Mn oxide for n-hexane elimination

    International Nuclear Information System (INIS)

    Picasso, Gino; Salazar, Ivonne; Lopez, Alcides

    2011-01-01

    Nanostructured Mn oxide based catalysts were synthesized by sol-gel method and corresponding bulk samples were prepared by precipitation procedure. In addition, some nanostructured samples based on Mn oxide supported on bentonite (montmorillonite) were prepared by incipient impregnation. Prior to calcination, the system was submitted by TEM analysis in order to study the peptization effect of acetic acid. The micrographs revealed that the sample prepared from nitrate precursor (0,06 M) achieved the highest monodispersion. After calcination of nanoparticles, TEM analysis has been performed in order to evaluate how extent the peptization agent is able to disperse. TEM micrographs of samples prepared from nitrate precursor revealed that the peptization effect increased with the concentration of acetic acid. XRD difractograms of Mn oxide samples showed characteristic well-defined diffraction peaks associated to Mn species as Mn 2 O 3 , Mn 3 O 4 and MnO 2 with more relative intensive signals in Mn 2 O 3 and Mn 3 O 4 spinel. Finally, synthesized manganese oxide nanoparticles were incorpored into layered structure of purified bentonite (montmorillonite) by incipient impregnation. Some essays with the unsupported and supported samples were performed for n-hexane combustion in a fixed bed reactor. Activity of bentonite supported sample was lower than its unsupported bulk sample counterpart; however the performance was higher than the corresponding to the support without active component probably due to more suitable structure position of nanoparticles into layered framework of starting bentonite. (author).

  16. Metal-Catalyst-Free Synthesis and Characterization of Single-Crystalline Silicon Oxynitride Nanowires

    Directory of Open Access Journals (Sweden)

    Shuang Xi

    2012-01-01

    Full Text Available Large quantities of single-crystal silicon oxynitride nanowires with high N concentration have been synthesized directly on silicon substrate at 1200°C without using any metal catalyst. The diameter of these ternary nanowires is ranging from 10 to 180 nm with log-normal distribution, and the length of these nanowires varies from a few hundreds of micrometers to several millimeters. A vapor-solid mechanism was proposed to explain the growth of the nanowires. These nanowires are grown to form a disordered mat with an ultrabright white nonspecular appearance. The mat demonstrates highly diffusive reflectivity with the optical reflectivity of around 80% over the whole visible wavelength, which is comparable to the most brilliant white beetle scales found in nature. The whiteness might be resulted from the strong multiscattering of a large fraction of incident light on the disordered nanowire mat. These ultra-bright white nanowires could form as reflecting surface to meet the stringent requirements of bright-white light-emitting-diode lighting for higher optical efficiency. They can also find applications in diverse fields such as sensors, cosmetics, paints, and tooth whitening.

  17. Mechanochemical synthesis of CaO•ZnO.K2CO3 catalyst: Characterization and activity for methanolysis of sunflower oil

    Directory of Open Access Journals (Sweden)

    Kesić Željka

    2015-01-01

    Full Text Available The goal of this study was to prepare CaO.ZnO catalyst which contain small amount of K2CO3 and analyze its activity for biodiesel synthesis. Catalyst was prepared using the following procedure: CaO and ZnO (molar ratio of 1:2, water and K2CO3 (in various amounts were mechanochemically treated and after milling heated at 700 oC in air atmosphere for obtaining mixed CaO•ZnO/xK2CO3 oxides (x = 0, 1, 2 and 4; mole of K2CO3 per 10 mole of CaO. All the samples were characterized by X-ray diffraction (XRD, inductively coupled plasma (ICP, X-ray photoelectron spectroscopy (XPS, thermogravimetric analysis (TGA, infrared spectroscopy (FTIR, scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS, particle size laser diffraction (PSLD distribution, solubility measurement of Ca, Zn and K ions in methanol as well as by determination of their alkalinity (Hammett indicator method. Prepared CaO•ZnO/xK2CO3 composite powders were tested as catalysts for methanolysis of sunflower oil at 70ºC using molar ratio of sunflower oil to methanol of 1:10 and with 2 mas% of catalyst based on oil weight. The presence of K2CO3 in prepared samples was found to increase the activity of catalyst, and that such effect is caused by homogeneous-heterogeneous catalysis of biodiesel synthesis. [Projekat Ministarstva nauke Republike Srbije, br. 45001

  18. Synthesis and characterization of bimetallic Pd-Ni catalysts in a CeO_2 matrix for the generation of H_2 by the reforming reaction of methanol

    International Nuclear Information System (INIS)

    Contreras C, R.

    2016-01-01

    The hydrothermal method was used for the synthesis of CeO_2 nano rods using Ce(NO_3)_3·6H_2O and NH_4OH. The catalytic support was calcined at 700 degrees Celsius. The synthesis of CeO_2 nano rods were impregnated with an aqueous solution of Ni(NO_3)_2·6H_2O by an incipient wetness impregnation method at an appropriate concentration to yield 5 and 15% of Ni in the catalysts. Then 0.5% of Pd was impregnated using PdCl_2. The samples obtained were calcined at 400 and reduced at 450 degrees Celsius. The catalytic materials were characterized by: temperature programmed reduction (TPR), Scanning Electron Microscopy (Sem) , surface area and X-ray diffraction (XRD) . Sem results showed that the CeO_2 is formed by nano rods and in lesser proportion semi spherical particles. Bet surface area of the catalysts decreases with Ni loading onto the CeO_2 nano rods. Pd O and Ni O were reduced at low and high temperature as was observed by TPR. The CeO_2 one-dimensional nano rods showed a highly crystalline structure with sharp diffraction peaks, with a typical fluorite structure (cubic structure of the CeO_2) and characteristic peaks corresponding to metallic Ni. No diffraction peaks of Pd were found. This is due to the low concentration of this metal in the catalyst. These catalysts showed high activity and selectivity to H_2 at maximum reaction temperature. According to the results of activity and selectivity, the catalysts with Pd-Ni are an alternative for the H_2 production in auto thermal reforming reaction of methanol. (Author)

  19. Stability of a Bifunctional Cu-Based Core@Zeolite Shell Catalyst for Dimethyl Ether Synthesis Under Redox Conditions Studied by Environmental Transmission Electron Microscopy and In Situ X-Ray Ptychography

    DEFF Research Database (Denmark)

    Baier, Sina; Damsgaard, Christian Danvad; Klumpp, Michael

    2017-01-01

    When using bifunctional core@shell catalysts, the stability of both the shell and core-shell interface is crucial for catalytic applications. In the present study, we elucidate the stability of a CuO/ZnO/Al2O3@ZSM-5 core@shell material, used for one-stage synthesis of dimethyl ether from synthesi...

  20. Novel synthesis of manganese and vanadium mixed oxide (V2O5/OMS-2) as an efficient and selective catalyst for the oxidation of alcohols in liquid phase

    International Nuclear Information System (INIS)

    Mahdavi, Vahid; Soleimani, Shima

    2014-01-01

    Graphical abstract: Oxidation of various alcohols is studied in the liquid phase over new composite mixed oxide (V 2 O 5 /OMS-2) catalyst using tert-butyl hydroperoxide (TBHP). The activity of V 2 O 5 /OMS-2 samples was considerably increased with respect to OMS-2 catalyst and these samples are found to be suitable for the selective oxidation of alcohols. - Highlights: • V 2 O 5 /K-OMS-2 with different V/Mn molar ratios prepared by the impregnation method. • Oxidation of alcohols was studied in the liquid phase over V 2 O 5 /K-OMS-2 catalyst. • V 2 O 5 /K-OMS-2 catalyst had excellent activity for alcohol oxidation. • Benzyl alcohol oxidation using excess TBHP followed a pseudo-first order kinetic. • The selected catalyst was reused without significant loss of activity. - Abstract: This work reports the synthesis and characterization of mixed oxide vanadium–manganese V 2 O 5 /K-OMS-2 at various V/Mn molar ratios and prepared by the impregnation method. Characterization of these new composite materials was made by elemental analysis, BET, XRD, FT-IR, SEM and TEM techniques. Results of these analyses showed that vanadium impregnated samples contained mixed phases of cryptomelane and crystalline V 2 O 5 species. Oxidation of various alcohols was studied in the liquid phase over the V 2 O 5 /K-OMS-2 catalyst using tert-butyl hydroperoxide (TBHP) and H 2 O 2 as the oxidant. Activity of the V 2 O 5 /K-OMS-2 samples was increased considerably with respect to K-OMS-2 catalyst due to the interaction of manganese oxide and V 2 O 5 . The kinetic of benzyl alcohol oxidation using excess TBHP over V 2 O 5 /K-OMS-2 catalyst was investigated at different temperatures and a pseudo-first order reaction was determined with respect to benzyl alcohol. The effects of reaction time, oxidant/alcohol molar ratio, reaction temperature, solvents, catalyst recycling potential and leaching were investigated

  1. Single-site SBA-15 supported zirconium catalysts. Synthesis, characterization and toward cyanosilylation reaction

    International Nuclear Information System (INIS)

    Xu, Wei; Yu, Bo; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

    2015-01-01

    Graphical abstract: Ligand-modified signal-site SBA-15 supported zirconium catalysts were synthesized by SOMC method and characterized by a variety of techniques. The zirconium surface complexes show high catalytic efficiency for cyanosilylation of benzaldehyde. - Highlights: • Some Zr active species have been anchored on the surface of SBA-15 by SOMC technique. • The structures of the Zr species have been characterized by a variety of techniques. • The anchored Zr species are single-sited surface complexes. • The Zr surface complexes are catalytic active for cyanosilylation of benzaldehyde. - Abstract: A successive anchoring of Zr(NMe 2 ) 4 , cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on dehydroxylated SBA-15 pretreated at 500 °C for 16 h (SBA-15 -500 ) was conducted by SOMC strategy in moderate conditions. The dehydoxylation of SBA-15 was monitored by in situ Fourier transform infrared spectroscopy (in situ FT-IR). The ligand-modified SBA-15 -500 supported zirconium complexes were characterized by in situ FT-IR, 13 C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MAS) and elemental analysis in detail, verifying that the surface zirconium species are single-sited. The catalytic activity of these complexes was evaluated by cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the structure of surface species and the configuration of the ligands

  2. Single-site SBA-15 supported zirconium catalysts. Synthesis, characterization and toward cyanosilylation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wei; Yu, Bo; Zhang, Ying; Chen, Xi; Zhang, Guofang, E-mail: gfzhang@snnu.edu.cn; Gao, Ziwei, E-mail: zwgao@snnu.edu.cn

    2015-01-15

    Graphical abstract: Ligand-modified signal-site SBA-15 supported zirconium catalysts were synthesized by SOMC method and characterized by a variety of techniques. The zirconium surface complexes show high catalytic efficiency for cyanosilylation of benzaldehyde. - Highlights: • Some Zr active species have been anchored on the surface of SBA-15 by SOMC technique. • The structures of the Zr species have been characterized by a variety of techniques. • The anchored Zr species are single-sited surface complexes. • The Zr surface complexes are catalytic active for cyanosilylation of benzaldehyde. - Abstract: A successive anchoring of Zr(NMe{sub 2}){sub 4}, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on dehydroxylated SBA-15 pretreated at 500 °C for 16 h (SBA-15{sub -500}) was conducted by SOMC strategy in moderate conditions. The dehydoxylation of SBA-15 was monitored by in situ Fourier transform infrared spectroscopy (in situ FT-IR). The ligand-modified SBA-15{sub -500} supported zirconium complexes were characterized by in situ FT-IR, {sup 13}C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MAS) and elemental analysis in detail, verifying that the surface zirconium species are single-sited. The catalytic activity of these complexes was evaluated by cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the structure of surface species and the configuration of the ligands.

  3. Chromium–tungsten–titanium mixed oxides solid catalyst for fatty acid methyl ester synthesis from palm fatty acid distillate

    International Nuclear Information System (INIS)

    Wan, Zuraida; Hameed, B.H.

    2014-01-01

    Highlights: • Chromium–tungsten–titanium mixed oxides as solid catalyst. • Catalyst used for esterification of palm fatty acid distillate to methyl esters. • The maximum methyl ester content is 83%. • Catalyst has shown good activity and can be recycled for 4 times. - Abstract: Chromium–tungsten–titanium mixed oxides solid catalysts were prepared and evaluated in the esterification of palm fatty acid distillate (PFAD) to produce fatty acid methyl ester (FAME). Esterification was conducted in a batch reactor at 110–200 °C temperature ranges. The catalysts were characterized by several techniques such as BET, TEM, FTIR, TGA, XRD, EDX and SEM. The treatment conditions during catalyst preparation, effect of reaction parameters, leaching of the active species and the recycled use of the catalyst were investigated. The catalyst with formula CrWTiO 2 was found to be the most active with maximum FAME content of 83% obtained at best reaction conditions of 170 °C for 3 h, 2:1 (methanol to oil molar ratio) and 2 wt.% catalyst dosage. The catalyst can be recycled for 4 times. The results revealed CrWTiO 2 good potentials for use in esterification of high acid value oil

  4. Effect of hierarchical meso–macroporous alumina-supported copper catalyst for methanol synthesis from CO2 hydrogenation

    International Nuclear Information System (INIS)

    Witoon, Thongthai; Bumrungsalee, Sittisut; Chareonpanich, Metta; Limtrakul, Jumras

    2015-01-01

    Highlights: • CO 2 hydrogenation over Cu-loaded unimodal and hierarchical alumina catalysts. • Cu-loaded hierarchical catalyst exhibited higher methanol selectivity and stability. • The presence of macropores reduced the probability of side reaction. - Abstract: Effects of pore structures of alumina on the catalytic performance of copper catalysts for CO 2 hydrogenation were investigated. Copper-loaded hierarchical meso–macroporous alumina (Cu/HAl) catalyst exhibited no significant difference in terms of CO 2 conversion with copper-loaded unimodal mesoporous alumina (Cu/UAl) catalyst. However, the selectivity to methanol and dimethyl ether of the Cu/HAl catalyst was much higher than that of the Cu/UAl catalyst. This was attributed to the presence of macropores which diminished the occurrence of side reaction by the shortening the mesopores diffusion path length. The Cu/HAl catalyst also exhibited much higher stability than the Cu/UAl catalyst due to the fast diffusion of water out from the catalyst pellets, alleviating the oxidation of metallic copper to CuO

  5. Hydrogen storage in graphite nanofibers: effect of synthesis catalyst and pretreatment conditions.

    Science.gov (United States)

    Lueking, Angela D; Yang, Ralph T; Rodriguez, Nelly M; Baker, R Terry K

    2004-02-03

    A series of graphite nanofibers (GNFs) that were subjected to various pretreatments were used to determine how modifications in the carbon structure formed during either synthesis or pretreatment steps results in active or inactive materials for hydrogen storage. The nanofibers possessing a herringbone structure and a high degree of defects were found to exhibit the best performance for hydrogen storage. These materials were exposed to several pretreatment procedures, including oxidative, reductive, and inert environments. Significant hydrogen storage levels were found for several in situ pretreatments. Examination of the nanofibers by high-resolution transmission electron microscopy (TEM) after pretreatment and subsequent hydrogen storage revealed the existence of edge attack and an enhancement in the generation of structural defects. These findings suggest that pretreatment in certain environments results in the creation of catalytic sites that are favorable toward hydrogen storage. The best pretreatment resulted in a 3.8% hydrogen release after exposure at 69 bar and room temperature.

  6. Impact of H2/CO ratios on phase and performance of Mn-modified Fe-based Fischer Tropsch synthesis catalyst

    International Nuclear Information System (INIS)

    Ding, Mingyue; Yang, Yong; Li, Yongwang; Wang, Tiejun; Ma, Longlong; Wu, Chuangzhi

    2013-01-01

    Highlights: ► Decreasing H 2 /CO ratio facilitated the conversion of Fe 3 O 4 to iron carbides on the surface layers. ► The formation of surface carbonaceous species was promoted in higher CO partial pressure. ► The formation of iron carbides on the surface of Fe 3 O 4 provided the FTS active sites. ► Decreasing H 2 /CO ratio promoted the product shifting towards heavy hydrocarbons. - Abstract: Impacts of H 2 /CO ratios on both the bulky and surface compositions of an iron–manganese based catalyst were investigated by XRD, MES, N 2 -physisorption, XPS and LRS. Fischer–Tropsch (F–T) synthesis performances were studied in a slurry-phase continuously stirred tank reactor. The characterization results showed that the fresh catalyst was comprised of the hematite, which was converted firstly to Fe 3 O 4 , and then carburized to iron carbides in both the bulk and surface regions under different H 2 /CO ratios atmosphere. Pretreatment in lower H 2 /CO ratio facilitated the formation of iron carbides on the surface of magnetite and surface carbonaceous species. During the F–T synthesis reaction, the catalyst reduced in lower H 2 /CO ratio presented higher catalytic activity, which is assigned probably to the formation of more iron carbides (especially for χ-Fe 5 C 2 ) on the surface of magnetite. The increase of CO partial pressure promoted the product distribution shifting towards heavy hydrocarbons

  7. Synthesis of bis- and tris(indolylmethanes catalyzed by an inorganic nano-sized catalyst followed by dehydrogenation to hyperconjugated products

    Directory of Open Access Journals (Sweden)

    Khorshidi Alireza

    2016-01-01

    Full Text Available A set of bis- and tris(indolylmethanes were prepared and dehydrogenated to their hyperconjugated products in a one-pot fashion. Nano-sized-SO3H functionalized mesoporous KIT-6 coated on magnetite nanoparticles (Fe3O4@SiO2@KIT-6-OSO3H was used as an efficient catalyst in the first step of synthesis, and dehydrogenation was performed by using (NH42S2O8 after removal of the catalyst. The catalyst was fully characterized by Fourier transform infrared spectroscopy (FT-IR, transmission electron microscopy (TEM and X-ray powder diffraction (XRD, as well as nitrogen adsorption-desorption isotherms. The bis- and tris(indolylmethanes were studied by UV-Vis spectroscopy before and after dehydrogenation, and effect of the ambient parameters on their spectra was investigated. It was found that bis- and tris(indolylmethanes have no considerable absorption in the visible range and what makes them colorful is partial dehydrogenation due to exposure to air. Our catalyst as a new combination of known materials, showed superiority in terms of yield, time, and mild reaction conditions in comparison with previous reports.

  8. Synthesis of honeycomb-like mesoporous nitrogen-doped carbon nanospheres as Pt catalyst supports for methanol oxidation in alkaline media

    Science.gov (United States)

    Zhang, Yunmao; Liu, Yong; Liu, Weihua; Li, Xiying; Mao, Liqun

    2017-06-01

    This paper reports the convenient synthesis of honeycomb-like mesoporous nitrogen-doped carbon spheres (MNCS) using a self-assembly strategy that employs dopamine (DA) as a carbon and nitrogen precursor and a polystyrene-b-poly(ethylene oxide) (PS173-b-PEO170) diblock copolymer as a soft template. The MNCS have large BET surface areas of up to 554 m2 g-1 and high nitrogen contents of up to 6.9 wt%. The obtained MNCS are used as a support for Pt catalysts, which promote methanol oxidation in alkaline media. The MNCS-supported Pt (Pt/MNCS) catalyst has a larger electrochemically active surface area (ESA) (89.2 m2 g-1) than does a commercially available Vulcan XC-72R supported Pt/C catalyst. Compared to the Pt/C catalyst, Pt/MNCS displays a higher peak current density (1007 mA mg-1) and is more stable during methanol oxidation. These improvements are attributed to the honeycomb-like porous structure of the MNCS and the introduction of nitrogen to the carbon support. The MNCS effectively stabilize Pt nanoparticles and assuage the agglomeration of the nanoparticles, suggesting that MNCS are potential and promising application as electrocatalyst supports in alkaline direct methanol fuel cells.

  9. SYNTHESIS OF UNSATURATED ESTERS VIA HIGHLY EFFICIENT ESTERIFICATION CATALYZED BY POLYMER GRAFTED QUARTERNARY AMMONIUM SALTS AS TRIPHASE CATALYSTS

    OpenAIRE

    LIANG, ZHENG YONG; WANG, LILI; LIU, HUI; HUANG, JIN SHUO

    2013-01-01

    A series of unsaturated esters were prepared via condensation of sodium carboxylates and alkenyl halide under the condition of macroporous polystyrene grafted quarternary ammonium salt as recyclable phase transfer catalyst, NaI as co-catalyst, Cu powder as inhibitor and H2O as solvent. Under optimal conditions, products yields are 78.2~ 96.0%. The catalyst can be convenient recycled and reutilized for about five times without losing its activity obviously.

  10. Synthesis and Characterization of Polyethylene/Starch Nanocomposites: A Spherical Starch-Supported Catalyst and In Situ Ethylene Polymerization.

    Science.gov (United States)

    Zhanga, Hao; Xi, Shixia; Wang, Shuwei; Liu, Jingsheng; Yoon, Keun-Byoung; Lee, Dong-Ho; Zhang, Hexin; Zhang, Xuequan

    2017-01-01

    In the present article, a novel spherical starch-supported vanadium (V)-based Ziegler-Natta catalyst was synthesized. The active centers of the obtained catalyst well dispersed in the starch through the SEM-EDX analysis. The effects of reaction conditions on ethylene polymerization were studied. The synthesized catalyst exhibited high activity toward ethylene polymerization in the presence of ethylaluminium sesquichloride (EASC) cocatalyst. Interestingly, the fiber shape PE was obtained directly during the polymerization process.

  11. Synthesis of a molecularly defined single-active site heterogeneous catalyst for selective oxidation of N-heterocycles.

    Science.gov (United States)

    Zhang, Yujing; Pang, Shaofeng; Wei, Zhihong; Jiao, Haijun; Dai, Xingchao; Wang, Hongli; Shi, Feng

    2018-04-13

    Generally, a homogeneous catalyst exhibits good activity and defined active sites but it is difficult to recycle. Meanwhile, a heterogeneous catalyst can easily be reused but its active site is difficult to reveal. It is interesting to bridge the gap between homogeneous and heterogeneous catalysis via controllable construction of a heterogeneous catalyst containing defined active sites. Here, we report that a molecularly defined, single-active site heterogeneous catalyst has been designed and prepared via the oxidative polymerization of maleimide derivatives. These polymaleimide derivatives can be active catalysts for the selective oxidation of heterocyclic compounds to quinoline and indole via the recycling of -C=O and -C-OH groups, which was confirmed by tracing the reaction with GC-MS using maleimide as the catalyst and by FT-IR analysis with polymaleimide as the catalyst. These results might promote the development of heterogeneous catalysts with molecularly defined single active sites exhibiting a comparable activity to homogeneous catalysts.

  12. Activity and selectivity regulation of synthesis gas reaction over supported ruthenium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, K; Nobusawa, T; Fukushima, T; Tominaga, H

    1985-01-01

    The catalytic activities of supported ruthenium for synthesis-gas conversion to hydrocarbons was found to be in the following order: TiOS > Nb2O3 > ZrO2 > SiO2 > Ta2O5 > Al2O3 > V2O5 > MoO3 > WO3 > MnO2 > ZnO. Turnover frequencies of the supported ruthenium increased with decrease in dispersion of the metal particles for every carrier material. Even the activities per unit weight of metals were higher for low-dispersion ruthenium of Al2O3, TiO2, and ZrO2. The chain-growth probability of a hydrocarbon product, which is characterized by the Schulz-Flory distribution, increased markedly with decrease in the metal dispersion irrespective of the carrier material. The catalytic activity of ruthenium particles with a dispersed ruthenium increased almost linearly with an increase in reaction pressure (up to at least 2.0 MPa). 23 references, 10 figures, 3 tables.

  13. Synthesis, characterization and application of a nano-manganese-catalyst as an efficient solid catalyst for solvent free selective oxidation of ethylbenzene, cyclohexene, and benzylalcohol

    Science.gov (United States)

    Habibi, Davood; Faraji, Ali Reza

    2013-07-01

    The object of this study is to synthesize the heterogeneous Mn-nano-catalyst (MNC) which has been covalently anchored on a modified nanoscaleSiO2/Al2O3, and characterized by FT-IR, UV-Vis, CHN elemental analysis, EDS, TEM, and EDX. The method is efficient for the highly selective oxidation of ethylbenzene, cyclohexene, and benzylalcohol without the need to any solvents, using tert-butyl hydroperoxide (TBHP) as an oxidant. Oxidation of ethylbenzene, cyclohexene, and benzylalcohol gave acetophenone, 2-cyclohexene-1-one and benzaldehyde, respectively, as major products. Reaction conditions have been optimized by considering the effect of various factors such as reaction time, amounts of substrates and oxidant, Mn-nano-catalyst and application of various solvents.

  14. Synthesis of Ordered Mesoporous CuO/CeO2 Composite Frameworks as Anode Catalysts for Water Oxidation

    Directory of Open Access Journals (Sweden)

    Vassiliki Markoulaki Ι

    2015-11-01

    Full Text Available Cerium-rich metal oxide materials have recently emerged as promising candidates for the photocatalytic oxygen evolution reaction (OER. In this article, we report the synthesis of ordered mesoporous CuO/CeO2 composite frameworks with different contents of copper(II oxide and demonstrate their activity for photocatalytic O2 production via UV-Vis light-driven oxidation of water. Mesoporous CuO/CeO2 materials have been successfully prepared by a nanocasting route, using mesoporous silica as a rigid template. X-ray diffraction, electron transmission microscopy and N2 porosimetry characterization of the as-prepared products reveal a mesoporous structure composed of parallel arranged nanorods, with a large surface area and a narrow pore size distribution. The molecular structure and optical properties of the composite materials were investigated with Raman and UV-Vis/NIR diffuse reflectance spectroscopy. Catalytic results indicated that incorporation of CuO clusters in the CeO2 lattice improved the photochemical properties. As a result, the CuO/CeO2 composite catalyst containing ~38 wt % CuO reaches a high O2 evolution rate of ~19.6 µmol·h−1 (or 392 µmol·h−1·g−1 with an apparent quantum efficiency of 17.6% at λ = 365 ± 10 nm. This OER activity compares favorably with that obtained from the non-porous CuO/CeO2 counterpart (~1.3 µmol·h−1 and pure mesoporous CeO2 (~1 µmol·h−1.

  15. Self-propagating high-temperature synthesis of Sr-doped LaMnO3 perovskite as oxidation catalyst

    International Nuclear Information System (INIS)

    Hirano, T.; Purwanto, H.; Watanabe, T.; Akiyama, T.

    2007-01-01

    Sr-doped LaMnO 3 perovskite oxide has been focused on as one of the alternative catalysts to precious metals such as platinum that are used for cleaning automotive emission gas. The conventional Solid-state reaction method is a popular productive process for perovskite oxide, however, it is time and energy consuming process because it requires repeated prolonged heat treatment at high temperatures. Therefore, the purposes of this work are to produce Sr-doped LaMnO 3 perovskite by using Self-propagating high-temperature synthesis (SHS) and experimentally examine the oxidation catalytic activity of the product for cleaning automotive emission gas. In the SHS, powders of La 2 O 3 , SrCO 3 , Mn and NaClO 4 were well mixed at the desired ratio and poured in a graphite crucible, where at one end it was ignited by using an electrically heated carbon foil. The wave of exothermic reaction due to oxidation of manganese propagated to the other end in a short time. The obtained products were characterized by means of XRD, FE-SEM, BET and particle size distribution analysis and then evaluated via catalytic oxidation tests by using propane in a fixed bed reactor at several temperatures. From the XRD analysis, the products had the desired composition of La 1-x Sr x MnO 3 (x = 0, 0.1, 0.2 and 0.4) perovskite, in which the replacing ratio x of La and Sr in the products was easily controlled by changing the mixing ratio of raw materials. The catalytic activity test showed that the samples exhibited good catalytic activity for propane oxidation over 200 deg. C , although the products had a relatively small surface area. SHS showed the potential for the production of a relatively inexpensive catalytic converter

  16. Controlled Synthesis of Heterostructured SnO2-CuO Composite Hollow Microspheres as Efficient Cu-Based Catalysts for the Rochow Reaction

    Directory of Open Access Journals (Sweden)

    Hezhi Liu

    2018-04-01

    Full Text Available In this work, we report the design and synthesis of a series of heterostructured SnO2-CuO hollow microspherical catalysts (H-SnO2(x-CuO, x is the weight ratio of Sn/Cu for the Rochow reaction. The microspherical catalysts with nanosheets and nanoparticles as building blocks were prepared by a facile one-pot hydrothermal method coupled with calcination. When tested for the Rochow reaction, the prepared H-SnO2(0.2-CuO composite exhibited higher dimethyldichlorosilane selectivity (88.2% and Si conversion (36.7% than the solid CuO, hollow CuO and other H-SnO2(x-CuO microspherical samples, because in the former there is a stronger synergistic interaction between CuO and SnO2.

  17. Synthesis NiAl1,0Fe1,0O4 catalyst by the combustion reaction to their use in the shift reaction (WGSR)

    International Nuclear Information System (INIS)

    Santos, P.T.A.; Costa, A.C.F.M.; Neiva, L.S.; Gama, L.; Argolo, F.; Andrade, H.M.C.

    2009-01-01

    This work aims at the synthesis of catalyst NiAl 1,0 Fe 1,0 O 4 by combustion reaction using urea as fuel, to evaluate its performance in the production of hydrogen by the reaction of displacement of water vapor (WGSR). The initial composition of the solution was based on valencia total oxidizing and reducing reagents based on the concepts of the chemistry of propellants, using container as a crucible of glassy silica. The resulting powder was characterized by X-ray diffraction, infrared spectroscopy, nitrogen adsorption isotherms (BET), scanning electronic microscope and catalytic tests. The DRX results reveal the presents majoritary phase NiAl 1,0 Fe 1,0 O 4 spinel, the catalyst presents surface area 28 m 2 /g and isotherms type III. Higher conversion CO/CO 2 of 75% CO conversion observed at 500 deg C and catalytic activity of 43 mmolg -1 .h -1 at 450 deg C. (author)

  18. A simple and efficient approach for synthesis of 1,4-dihydro-pyridines using nano-crystalline solid acid catalyst

    Directory of Open Access Journals (Sweden)

    A. Moatari

    2013-09-01

    Full Text Available A simple highly versatile and efficient synthesis of various 1,4-dihydropyridines in the condensation of aromatic aldehydes with β-dicarbonyl compounds and ammonium acetate in the presence of nano-sulfated zirconia, nano-structured ZnO, nano-γ-alumina and nano-ZSM-5 zeolites, as catalyst in the ethanol at moderate temperature is presented. The advantages of method are short reaction times and milder conditions and easy work-up. The catalysts can be recovered for the subsequent reactions and reused without any appreciable loss of efficiency.DOI: http://dx.doi.org/10.4314/bcse.v27i3.12

  19. Rapid in situ synthesis of spherical microflower Pt/C catalyst via spray-drying for high performance fuel cell application

    Energy Technology Data Exchange (ETDEWEB)

    Balgis, R.; Ogi, T.; Okuyama, K. [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Higashi Hiroshima, Hiroshima (Japan); Anilkumar, G.M.; Sago, S. [Research and Development Centre, Noritake Co., Ltd., Higashiyama, Miyoshi, Aichi (Japan)

    2012-08-15

    A facile route for the rapid in situ synthesis of platinum nanoparticles on spherical microflower carbon has been developed. An aqueous precursor slurry containing carbon black, polystyrene latex (PSL), polyvinyl alcohol, and platinum salt was spray-dried, followed by calcination to simultaneously reduce platinum salt and to decompose PSL particles. Prepared Pt/C catalyst showed high-performance electrocatalytic activity with excellent durability. The mass activity and specific activity values were 132.26 mA mg{sup -1} Pt and 207.62 {mu}A cm{sup -2} Pt, respectively. This work presents a future direction for the production of high-performance Pt/C catalyst in an industrial scale. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. One-pot synthesis of linear- and three-arm star-tetrablock quarterpolymers via sequential metal-free ring-opening polymerization using a "catalyst switch" strategy

    KAUST Repository

    Zhao, Junpeng; Pahovnik, David; Gnanou, Yves; Hadjichristidis, Nikolaos

    2014-01-01

    A "catalyst switch" strategy has been used to sequentially polymerize four different heterocyclic monomers. In the first step, epoxides (1,2-butylene oxide and ethylene oxide) were successively polymerized from a monohydroxy or trihydroxy initiator in the presence of a strong phosphazene base promoter (t-BuP4). Then, an excess of diphenyl phosphate (DPP) was introduced, followed by addition and polymerization of a cyclic carbonate (trimethylene carbonate) and a cyclic ester (δ-valerolactone or ε-caprolactone). DPP acted as both neutralizer of the phosphazenium alkoxide (polyether chain end) and activator of the cyclic carbonate/ester. Using this method, linear- and star-tetrablock quarterpolymers were prepared in one pot. This work is emphasizing the strength of the previously developed catalyst switch strategy for the facile metal-free synthesis of complex macromolecular architectures. © 2014 Wiley Periodicals, Inc.

  1. One-pot synthesis of linear- and three-arm star-tetrablock quarterpolymers via sequential metal-free ring-opening polymerization using a "catalyst switch" strategy

    KAUST Repository

    Zhao, Junpeng

    2014-08-06

    A "catalyst switch" strategy has been used to sequentially polymerize four different heterocyclic monomers. In the first step, epoxides (1,2-butylene oxide and ethylene oxide) were successively polymerized from a monohydroxy or trihydroxy initiator in the presence of a strong phosphazene base promoter (t-BuP4). Then, an excess of diphenyl phosphate (DPP) was introduced, followed by addition and polymerization of a cyclic carbonate (trimethylene carbonate) and a cyclic ester (δ-valerolactone or ε-caprolactone). DPP acted as both neutralizer of the phosphazenium alkoxide (polyether chain end) and activator of the cyclic carbonate/ester. Using this method, linear- and star-tetrablock quarterpolymers were prepared in one pot. This work is emphasizing the strength of the previously developed catalyst switch strategy for the facile metal-free synthesis of complex macromolecular architectures. © 2014 Wiley Periodicals, Inc.

  2. Efficient Synthesis of Ethanol from CH4 and Syngas on a Cu-Co/TiO2 Catalyst Using a Stepwise Reactor

    Science.gov (United States)

    Zuo, Zhi-Jun; Peng, Fen; Huang, Wei

    2016-10-01

    Ethanol synthesis from CH4 and syngas on a Cu-Co/TiO2 catalyst is studied using experiments, density functional theory (DFT) and microkinetic modelling. The experimental results indicate that the active sites of ethanol synthesis from CH4 and syngas are Cu and CoO, over which the ethanol selectivity is approximately 98.30% in a continuous stepwise reactor. DFT and microkinetic modelling results show that *CH3 is the most abundant species and can be formed from *CH4 dehydrogenation or through the process of *CO hydrogenation. Next, the insertion of *CO into *CH3 forms *CH3CO. Finally, ethanol is formed through *CH3CO and *CH3COH hydrogenation. According to our results, small particles of metallic Cu and CoO as well as a strongly synergistic effect between metallic Cu and CoO are beneficial for ethanol synthesis from CH4 and syngas on a Cu-Co/TiO2 catalyst.

  3. Fe3C-based oxygen reduction catalysts: synthesis, hollow spherical structures and applications in fuel cells

    DEFF Research Database (Denmark)

    Hu, Yang; Jensen, Jens Oluf; Zhang, Wei

    2015-01-01

    We present a detailed study of a novel Fe3C-based spherical catalyst with respect to synthetic parameters, nanostructure formation, ORR active sites and fuel cell demonstration. The catalyst is synthesized by high temperature autoclave pyrolysis using decomposing precursors. Below 500 °C, melamine...

  4. Synthesis and characterization of PtRu/C catalysts obtained by colloidal and deposition methods for fuel cell applications

    Directory of Open Access Journals (Sweden)

    Egberto Gomes Franco

    2005-06-01

    Full Text Available The purpose of this investigation was to compare catalysts produced by the Bönnemann - colloidal method (PtRu (B1 and PtRu (B2, and those produced by the spontaneous deposition method (PtRu (SD. The catalysts produced by both methods had good electrochemical behavior for methanol oxidation for proton exchange membrane fuel cell applications. The structure of the catalyst was examined by transmission electron microscopy (TEM. Energy dispersive spectroscopic analysis (EDS was used to determine the semi-quantitative composition of the catalysts, and the electrochemical behavior was determined by cyclic voltammetry (CV. The diffractograms of the binary catalysts revealed platinum and ruthenium as the only crystalline phases, as per ICDD data base. The PtRu (B1 catalyst, treated in a reducing atmosphere, has the same structure as PtRu (B2, treated in an oxidising/reducing atmosphere, except that the crystallite size was around 1.7 nm for PtRu (B1 instead of 9.9 nm for PtRu (B2. The catalysts PtRu (B2 and PtRu (SD showed similar cyclic voltammetric behavior, which was better than that of PtRu (B1. Both methods are suitable for the production of electrocatalysts for fuel cell applications. The colloidal method is more expensive than the deposition method, but the former permits the production of ternary and quaternary catalyst systems with enhanced CO tolerance.

  5. Continuous synthesis of methanol: heterogeneous hydrogenation of ethylene carbonate over Cu/HMS catalysts in a fixed bed reactor system.

    Science.gov (United States)

    Chen, Xi; Cui, Yuanyuan; Wen, Chao; Wang, Bin; Dai, Wei-Lin

    2015-09-18

    Continuous fixed-bed catalytic hydrogenation of ethylene carbonate (EC) to methanol and ethylene glycol (EG), an emerging synthetic process of methanol via indirect conversion of CO2, was successfully performed over Cu/HMS catalysts prepared by the ammonia evaporation (AE) method. The catalysts possessed superb performance with a conversion of 100% and a selectivity to methanol of 74%.

  6. Carbon/H-ZSM-5 composites as supports for bi-functional Fischer-Tropsch synthesis catalysts

    NARCIS (Netherlands)

    Valero-Romero, M.J.; Sartipi, S.; Sun, X.; Rodríguez-Mirasol, J.; Cordero, T.; Kapteijn, F.; Gascon, J.

    2016-01-01

    Mesoporous H-ZSM-5–carbon composites, prepared via tetrapropylammonium hydroxide (TPAOH) post treatment of H-ZSM-5 followed by deposition of pyrolytic carbon, have been used as the support for the preparation of Co-based Fischer–Tropsch catalysts. The resulting catalysts display an improved

  7. An investigation of the physical and chemical changes occuring in a Fischer-Tropsch fixed bed catalyst during hydrocarbon synthesis

    International Nuclear Information System (INIS)

    Duvenhage, D.J.

    1990-01-01

    Deactivation studies: making use of fixed bed reactors, wet chemical analysis, surface area, pore volume determinations and X-ray diffraction spectrometry, scanning electron microscope spectrometry and secondary ion mass spectrometry techniques; were performed on a low temperature iron Fischer-Tropsch catalyst. It was revealed that this catalyst is mainly deactivated by sulphur poisoning, oxidation of the catalytic reactive phases, sintering of the iron crystallites and to a lesser extent deactivation through fouling of the catalytic surface by carbonaceous deposits. It was found that the top entry section of the catalyst bed deactivated relatively fast, the bottom exit section also deactivated, but not as fast as the top section. The central portion of the catalyst bed was least affected. Sulphur contaminants in the feed gas, even though present in only minute quantities, results in a loss of catalyst performance of the top section of the catalyst bed, while water, produced as a product from the Fischer-Tropsch reaction, oxidized and sintered the catalyst over the bottom section of the catalyst bed. 88 figs., 7 tabs., 224 refs

  8. DFT study of gases adsorption on sharp tip nano-catalysts surface for green fertilizer synthesis

    Science.gov (United States)

    Yahya, Noorhana; Irfan, Muhammad; Shafie, Afza; Soleimani, Hassan; Alqasem, Bilal; Rehman, Zia Ur; Qureshi, Saima

    2016-11-01

    The energy minimization and spin modifications of sorbates with sorbents in magnetic induction method (MIM) play a vital role in yield of fertilizer. Hence, in this article the focus of study is the interaction of sorbates/reactants (H2, N2 and CO2) in term of average total adsorption energies, average isosteric heats of adsorption energies, magnetic moments, band gaps energies and spin modifications over identical cone tips nanocatalyst (sorbents) of Fe2O3, Fe3O4 (magnetic), CuO and Al2O3 (non-magnetic) for green nano-fertilizer synthesis. Study of adsorption energy, band structures and density of states of reactants with sorbents are purely classical and quantum mechanical based concepts that are vividly illustrated and supported by ADSORPTION LOCATOR and Cambridge Seriel Total Energy Package (CASTEP) modules following classical and first principle DFT simulation study respectively. Maximum values of total average energies, total average adsorption energies and average adsorption energies of H2, N2 and CO2 molecules are reported as -14.688 kcal/mol, -13.444 kcal/mol, -3.130 kcal/mol, - kcal/mol and -6.348 kcal/mol over Al2O3 cone tips respectively and minimum over magnetic cone tips. Whereas, the maximum and average minimum values of average isosteric heats of adsorption energies of H2, N2 and CO2 molecules are figured out to be 3.081 kcal/mol, 4.842 kcal/mol and 6.848 kcal/mol, 0.988 kcal/mol, 1.554 kcal/mol and 2.236 kcal/mol over aluminum oxide and Fe3O4 cone tips respectively. In addition to the adsorption of reactants over identical cone sorbents the maximum and minimum values of net spin, electrons and number of bands for magnetite and aluminum oxide cone structures are attributed to 82 and zero, 260 and 196, 206 and 118 for Fe3O4 and Al2O3 cones respectively. Maximum and least observed values of band gap energies are figured out to be 0.188 eV and 0.018 eV with Al2O3 and Fe3O4 cone structures respectively. Ultimately, with the adsorption of reactants an

  9. Direct synthesis of ethanol from dimethyl ether and syngas over combined H-Mordenite and Cu/ZnO catalysts.

    Science.gov (United States)

    Li, Xingang; San, Xiaoguang; Zhang, Yi; Ichii, Takashi; Meng, Ming; Tan, Yisheng; Tsubaki, Noritatsu

    2010-10-25

    Ethanol was directly synthesized from dimethyl ether (DME) and syngas with the combined H-Mordenite and Cu/ZnO catalysts that were separately loaded in a dual-catalyst bed reactor. Methyl acetate (MA) was formed by DME carbonylation over the H-Mordenite catalyst. Thereafter, ethanol and methanol were produced by MA hydrogenation over the Cu/ZnO catalyst. With the reactant gas containing 1.0% DME, the optimized temperature for the reaction was at 493 K to reach 100% conversion. In the products, the yield of methanol and ethanol could reach 46.3% and 42.2%, respectively, with a small amount of MA, ethyl acetate, and CO(2). This process is environmentally friendly as the main byproduct methanol can be recycled to DME by a dehydration reaction. In contrast, for the physically mixed catalysts, the low conversion of DME and high selectivity of methanol were observed.

  10. Preparation of Copper (II) Containing Phosphomolybdic Acid Salt as Catalyst for the Synthesis of Biodiesel by Esterification.

    Science.gov (United States)

    Cai, Jie; Zhang, Qiu-Yun; Wei, Fang-Fang; Huang, Jin-Shu; Feng, Yun-Mei; Ma, Hai-Tao; Zhang, Yutao-

    2018-04-01

    Copper (II) containing phosphomolybdic acid (PMA) catalysts were synthesized by ion exchange method and characterization using various physico-chemical techniques such as X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), thermogravimetric (TG) and scanning electron microscopy (SEM). The characterization results showed that the Keggin ions were retained in the catalysts and possessed well thermal stability. The catalytic esterification of lauric acid with methanol could be easily achieved about 78.7% conversion under optimum condition, the catalyst also contributed to the stability of the catalyst in which it can be reused for a certain time. This study demonstrated an alternative approach to biodiesel production with high efficiency by Cu (II) ion exchanged phosphomolybdic acid catalyst in the esterification catalytic.

  11. Preparation, characterization and testing of SiC-based catalytic sponges as structured catalysts for Fischer-Tropsch synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Baudry, A.; Schaub, G. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Engler-Bunte-Inst.

    2011-07-01

    Solid sponges (open-cell foams) may be used as catalyst support, due to favorable thermal properties and low pressure drop. As an example, they may lead to improved temperature control in Fischer-Tropsch applications, if compared to fixed beds of catalyst particles. The aim of this study was to develop and test a wet method for impregnating ceramic foam materials with a CoRe/{gamma}-Al{sub 2}O{sub 3} catalyst. Defined catalyst layers were generated on 20 ppi SiC-sponges. Resulting catalytic activities are nearly identical to those of the corresponding powder catalyst material. The difference observed can be explained by either mass transfer limitation or backmixing in the fixed bed configuration used. (orig.)

  12. Modeling and optimization of Fischer-Tropsch synthesis over Co-Mn-Ce/SiO_2 catalyst using hybrid RSM/LHHW approaches

    International Nuclear Information System (INIS)

    Zohdi-Fasaei, Hossein; Atashi, Hossein; Farshchi Tabrizi, Farshad; Mirzaei, Ali Akbar

    2017-01-01

    Operating conditions considerably affect the energy required for Fischer-Tropsch synthesis, depending on the catalyst composition and reactor type (catalyst system). This paper reports the use of cobalt-manganese-cerium supported on silica as a novel CO hydrogenation catalyst, to produce hydrocarbons in a fixed bed micro-reactor. Response surface methodology (RSM) was applied to study the effects of temperature, pressure, feed ratio and their interactions on CO consumption rate, and the selectivity of light olefins (light olefinity), methane and C_5_+ hydrocarbons. Quadratic mathematical models adequately described the responses in this catalyst system. According to Langmuir Hinshelwood Hougen Watson (LHHW) approach, kinetic mechanism of the reaction was found to be an associative adsorption of H_2 and CO. Statistical analysis demonstrated that pressure and feed ratio were the most important factors for the production of C_5_+ and light alkenes, respectively. Model graphs indicated that minimum methane selectivity was achieved at 523.15 k and 2 bar. The maximum amounts of light olefins and heavier hydrocarbons were obtained at H_2/CO = 1 and H_2/CO = 2, respectively. Characterization of precursor and calcined catalyst (before and after the reaction) was carried out using SEM and BET techniques. - Highlights: • The performance of a new catalytic system was studied using RSM as a research plan. • Interactions between significant factors were investigated using mathematical models. • Based on LHHW approach, kinetic mechanism was molecular adsorptions of H_2 and CO. • RSM rate expression was in consistent with the LHHW kinetic model. • Hybrid RSM/LHHW is promising for optimization, mechanism and selectivity studies.

  13. Effect of CO{sub 2} and H{sub 2}O content in syngas on activity and selectivity of a cobalt based Fischer-Tropsch synthesis catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Poehlmann, F.; Kaiser, P.; Kern, C.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2013-11-01

    When liquid hydrocarbons are to be used as CO{sub 2} neutral storage media for electrical energy, it is necessary to convert CO{sub 2} from e.g. flue gas and hydrogen from water electrolysis to synthesis gas (CO/H{sub 2}). This can be achieved by a high temperature reverse water gas shift (RWGS) reaction. Due to thermodynamic limitations, the product gas of RWGS reactors operated at technically feasible temperatures of around 900 C will always contain significant amounts of water and carbon dioxide, which can influence the activity of Fischer-Tropsch synthesis (FTS) catalysts for the actual hydrocarbon production. In this study, a commercial cobalt catalyst was investigated under low temperature FTS conditions (2.5 MPa, 215 C) regard to activity and selectivity in the presence of H{sub 2}O and CO{sub 2}. A continuous flow apparatus including a fixed-bed reactor for the synthesis step was used to conduct all experiments. The experimental data reveals that the CO/CO{sub 2}-ratio does not affect the activity and product selectivity until the CO{sub 2}-concentration reaches 75 vol.-% (CO{sub 2}/(CO+CO{sub 2})). On increasing the carbon dioxide concentration to 100 vol.-% (H{sub 2}/CO{sub 2} = 2), the methane selectivity rose up to 70 % and even above. Addition of water caused an initial loss of activity. After the initial loss of activity the FT catalyst activity was found to remain constant, irrespectively of if the water was removed from the feed or not. Thus, the deactivation was permanent. (orig.)

  14. Synthesis, characterization and electrochemical studies of Pt- W/C catalyst for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Ahmed, R.; Shahid, S.; Ansari, M. S.

    2013-01-01

    Pt-W/C catalyst was synthesized by slow reduction of platinum and tungsten solutions in the desired ratio with subsequent deposition on the Vulcan carbon already added to the solution. Crystallite size of catalyst was about 9 nm and its density, cell volume, d-spacing and lattice parameter were also calculated. EDX analysis of the catalyst was also done. Electrochemical surface area of the catalyst was determined by cyclic voltammetry (CV). CV of the catalyst was done both in acidic and basic media to find out the peak potential, peak current, specific activity and mass activity of the catalyst. Peak potential versus scan rate plots showed that the electro oxidation of methanol is an irreversible process. Tafel equation was used to plot polarization curves to find out the exchange current density. Higher values of exchange current indicate better catalysts. Specific activities of the catalyst were determined in acidic and basic media and it was found that the specific activity in basic media increased substantially as compared to acidic media. The specific activity in acidic media was 83 mA/mg pt whereas in basic media it was 137mA/mg pt which is a substantial increase. Heterogeneous rate constant in acidic media was 6.15 * 10-6 cm/ s and in basic media it was 4.92 * 10-5 cm/s which is much higher in basic media. In this binary catalyst addition of tungsten has increased the catalytic activity but it is non-noble metal thus will decrease the cost. Stability studies of the catalyst were done upto fifty cycles both in acidic and basic media and was found quite stable in both the media. (author)

  15. Synthesis, characterization and electrochemical studies of Pt-W/C catalyst for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Ahmed, Riaz; Shahid, Saliha; Ansari, Muhammad Shahid

    2014-01-01

    Pt-W/C catalyst was synthesized by slow reduction of platinum and tungsten solutions in the desired ratio with subsequent deposition on the Vulcan carbon already added to the solution. Crystallite size of catalyst was about 9 nm and its density, cell volume, d-spacing and lattice parameter were also calculated. EDX analysis of the catalyst was also done. Electrochemical surface area of the catalyst was determined by cyclic voltammetry (CV). CV of the catalyst was done both in acidic and basic media to find out the peak potential, peak current, specific activity and mass activity of the catalyst. Peak potential versus scan rate plots showed that the electro oxidation of methanol is an irreversible process. Tafel equation was used to plot polarization curves to find out the exchange current density. Higher values of exchange current indicate better catalysts. Specific activities of the catalyst were determined in acidic and basic media and it was found that the specific activity in basic media increased substantially as compared to acidic media. The specific activity in acidic media was 83 mA/mg pt whereas in basic media it was 137mA/mg pt which is a substantial increase. Heterogeneous rate constant in acidic media was 6.15 x 10 −6 cm/ s and in basic media it was 4.92 x 10 −5 cm/s which is much higher in basic media. In this binary catalyst addition of tungsten has increased the catalytic activity but it is non-noble metal thus will decrease the cost. Stability studies of the catalyst were done upto fifty cycles both in acidic and basic media and was found quite stable in both the media

  16. A new Ni(II complex as a novel and efficient recyclable catalyst for the synthesis of pyrano[2,3-d]pyrimidines

    Directory of Open Access Journals (Sweden)

    M. Habibi Kheirabadi

    2016-12-01

    Full Text Available A simple and highly efficient one-pot three-component synthesis of a series of pyrido[2,3-d]pyrimidines from the condensation of barbituric acid, malononitrile and aromatic aldehydes using catalytic amount of a new Ni(II complex based on 5-nitro-N1-((pyridin-2-ylmethylene benzene-1,2-diamine (NiL is reported. This new heterogeneous catalyst has the advantages of being environmentally friendly, simple work-up and high yields character.

  17. A Combined Synthetic and DFT Study on the Catalyst-Free and Solvent-Assisted Synthesis of 1,3,4-Oxadiazole-2-thiol Derivatives

    Directory of Open Access Journals (Sweden)

    Mohammad Soleiman-Beigi

    2013-01-01

    Full Text Available A novel practical and efficient catalyst-free method for the synthesis of 5-substituted 1,3,4-oxadiazole-2-thiols has been developed, which is assisted by reaction solvent (DMF. The solvent effects on product selectivity were studied based on Onsager’s reaction field theory of electrostatic solvation. The ab initio theoretical studies on the effect of solvents on the process also supported the suitability of DMF as the reaction medium for the preparation of 1,3,4-oxadiazole-2-thiol derivatives.

  18. CuI nanoparticles as a remarkable catalyst in the synthesis of benzo[b][1,5]diazepines: an eco-friendly approach.

    Science.gov (United States)

    Ghasemzadeh, Mohammad Ali; Safaei-Ghomi, Javad

    2015-01-01

    Highly efficient CuI nanoparticles catalyzed one-pot synthesis of some benzo[b][1,5]diazepine derivatives via multi-component condensation of aromatic diamines, Meldrum's acid and isocyanides. The present approach creates a variety of benzo[b][1,5]diazepines as pharmaceutical and biologically active heterocyclic compounds in excellent yields and short reaction times. The salient features of the copper iodide nanoparticles are: easy preparation, cost-effective, high stability, low loading and reusability of the catalyst. The prepared copper iodide nanoparticles were fully characterized by XRD, EDX, FT-IR, SEM and TEM analysis.

  19. Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst

    Directory of Open Access Journals (Sweden)

    Dewi Tristantini

    2016-03-01

    Received: 10th November 2015; Revised: 10th February 2016; Accepted: 16th February 2016 How to Cite: Tristantini, D., Suwignjo, R.K. (2016. Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 84-92. (doi:10.9767/bcrec.11.1.424.84-92 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.424.84-92

  20. Synthesis of 2-Substituted Benzofurans from o-Iodophenols and Terminal Alkynes with a Recyclable Palladium Catalyst Supported on Nano-sized Carbon Balls under Copper- and Ligand-Free Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yum, Eul Kgun; Yang, Okkyung; Kim, Jieun; Park, Hee Jank [Chungnam National Univ., Daejeon (Korea, Republic of)

    2013-09-15

    We have developed a one-step synthesis of benzofurans from o-iodophenol and various terminal alkynes, by using Pd catalyst supported on nano-sized carbon balls (NCB) under copper- and ligand free conditions. This recyclable catalyst could be reused more than 5 times in the same heteroannulation reaction. The results have demonstrated that diverse 2-substituted benzofurans with tolerant functional groups can be prepared simply and conveniently under these conditions.

  1. Synthesis of 2-Substituted Benzofurans from o-Iodophenols and Terminal Alkynes with a Recyclable Palladium Catalyst Supported on Nano-sized Carbon Balls under Copper- and Ligand-Free Conditions

    International Nuclear Information System (INIS)

    Yum, Eul Kgun; Yang, Okkyung; Kim, Jieun; Park, Hee Jank

    2013-01-01

    We have developed a one-step synthesis of benzofurans from o-iodophenol and various terminal alkynes, by using Pd catalyst supported on nano-sized carbon balls (NCB) under copper- and ligand free conditions. This recyclable catalyst could be reused more than 5 times in the same heteroannulation reaction. The results have demonstrated that diverse 2-substituted benzofurans with tolerant functional groups can be prepared simply and conveniently under these conditions

  2. Wet chemical synthesis of nickel supported on alumina catalysts; Sintese de catalisadores de niquel suportado em alumina por via umida

    Energy Technology Data Exchange (ETDEWEB)

    Freire, Ranny Rodrigues; Costa, Talita Kenya Oliveira; Morais, Ana Carla da Fonseca Ferreira; Costa, Ana Cristina Figueiredo de Melo; Freitas, Normanda Lino de, E-mail: normanda@ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2016-07-01

    Heterogenic catalysts are those found to be in a different phase on the reaction when compared to the reactants and products. Preferred when compared to homogeneous catalysts due to the easiness on which the separation is processed. The objective of this study is to obtain and characterize Alumina based catalysts impregnated with Nickel (Al{sub 2}O{sub 3}), by wet impregnation. The alumina was synthesized by combustion reaction. Before and after the impregnation the catalysts were characterized by X-ray diffraction (XRD), granulometric analysis, the textural analysis will be held by nitrogen adsorption (BET), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results show a presence of a stable crystalline phase of Al2O3 in all the studied samples and after the impregnation the second phase formed was of NiO and NiAl{sub 2}O{sub 4}. The Al{sub 2}O{sub 3} e Ni/Al{sub 2}O{sub 3} catalysts resulted in clusters with a medium diameter of 18.9 and 14.2 μm, respectively. The catalysts show a medium-pore characteristic (medium pore diameter between 2 and 50 nm), the superficial area to Al{sub 2}O{sub 3} and Ni/Al{sub 2}O{sub 3} catalysts were 8.69 m{sup 2}/g and 5.56 m{sup 2}/g, respectively. (author)

  3. Based on a new support for synthesis of highly efficient palladium/hydroxyapatite catalyst for ethanol electrooxidation

    International Nuclear Information System (INIS)

    Cui, Qian; Chao, Shujun; Bai, Zhengyu; Yan, Huiying; Wang, Kui; Yang, Lin

    2014-01-01

    Based on a new support, hydroxyapatite (HAP), a facile and low–cost preparation of palladium/hydroxyapatite catalyst for ethanol electrooxidation is introduced in this paper through a solvothermal reaction without additives. HAP was employed as the catalyst support for its hydroxyl–rich surface in order to increase the stability and utilization ratio of catalyst. According to transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and X–ray diffraction (XRD) measurements, the as–prepared Pd nanoparticles with face–centered cubic crystal structure were evenly deposited on the surface of HAP. Cyclic voltammetry and chronoamperometry tests demonstrated that the Pd/HAP catalyst possessed a much higher current density (246 mA cm −2 ) than the Pd/C catalyst (109 mA cm −2 ) towards ethanol electrooxidation, and better stability as well. In the direct ethanol fuel cell (DEFC) test, Pd/HAP catalyst gives better performance than that with Pd/C in terms of both open-circuit voltage (OCV) and power density. These results indicate that the HAP is a better support and the catalyst developed in this study may be a better candidate for DEFCs. A possible mechanism consistent with the experimental is also proposed

  4. Controllable synthesis in a continuous mode of unsupported molybdenum catalysts with micro/nano size for heavy oil upgrading

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Hill, J.M.; Pereira Almao, P.R. [Calgary Univ., AB (Canada)

    2004-07-01

    Heavy oils contain significant amounts of impurities compared to conventional oils, thereby posing a challenge for hydroprocessing operations at refineries. Hydrodesulfurization is one of the important reactions involved in hydroprocessing. Transition metal sulfides have excellent properties in terms of sulphur removal. Molybdenum based catalysts have been used extensively in the petroleum industry for hydrotreating heavy oil fractions. Supported molybdenum based catalysts suffer strong deactivation in the traditional hydrotreating process due to the deposition of carbonaceous components on the surface of the catalyst when they are used in conventional fixed bed reactors. Unsupported catalysts have higher catalytic activity with better metal dispersion. Laboratory experiments were conducted in which micro/nano size unsupported molybdenum catalysts were synthesized from a water/oil emulsion. The catalysts were prepared in a continuous mode for online application to hydroprocessing or in situ upgrading. Dispersed molybdenum catalysts are more suitable for processing heavier feeds because they are less prone to deactivation. Also, their submicron size ensure high activities due to a large specific surface area. They are also sufficiently small to be readily dispersed in the residual oil. 4 refs., 1 tab., 2 figs.

  5. 3-[(3-(Trimethoxysilylpropylthio]propane-1-oxy-sulfonic acid: An efficient recyclable heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H-ones/thiones

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao Jetti

    2017-05-01

    Full Text Available An efficient method for the synthesis of 3,4-dihydropyrimidin-2(1H-ones and thiones through one-pot three-component reaction of ethyl acetoacetate, aryl aldehyde and urea or thiourea in ethanol using 3-[(3-(trimethoxysilylpropylthio]propane-1-oxy-sulfonic acid as catalyst is described. The use of 3-[(3-(trimethoxysilylpropylthio]propane-1-oxy-sulfonic acid as a catalyst offers several advantages such as high yields, short reaction times, mild reaction condition and a recyclable catalyst with a very easy work up.

  6. Non-Covalent Supported of l-Proline on Graphene Oxide/Fe3O4 Nanocomposite: A Novel, Highly Efficient and Superparamagnetically Separable Catalyst for the Synthesis of Bis-Pyrazole Derivatives

    Directory of Open Access Journals (Sweden)

    Mosadegh Keshavarz

    2018-02-01

    Full Text Available A superparamagnetic graphene oxide/Fe3O4/l-proline nano hybrid that was obtained from the non-covalent immobilization of l-proline on graphene oxide/Fe3O4 nanocomposite was used as a new magnetically separable catalyst for the efficient synthesis of 4,4′-(arylmethylenebis(1H-pyrazol-5-ol derivatives. The prepared heterogeneous catalyst was characterized using FTIR, TGA, DTG, XRD, TEM, SEM, and elemental analysis techniques. Short reaction times (5–15 min, excellent yields (87–98%, and simple experimental procedure with an easy work-up are some of the advantages of the introduced catalyst.

  7. B2O3/Al2O3 as a new, highly efficient and reusable heterogeneous catalyst for the selective synthesis of β-enamino ketones and esters under solvent-free conditions

    International Nuclear Information System (INIS)

    Chen, Jiu-Xi; Gao, Wen-Xia; Jin, Hui-Le; Ding, Jin-Chang; Wu, Hua-Yue

    2010-01-01

    Boron oxide adsorbed on alumina (B 2 O 3 /Al 2 O 3 ) has been found to be a new and highly efficient heterogeneous catalyst for the synthesis of β-enamino ketones and esters by the enamination of various primary and secondary amines with β-dicarbonyl compounds under solvent-free conditions. The important features of this methodology are broad substrate scope, high yield, no requirement of metal catalysts, high regio- and chemoselectivity and environmental friendliness. In addition, the catalyst could be recovered easily after the reactions and reused without evident loss of reactivity. (author)

  8. Ruthenium Modification on Mn and Zr-Modified Co/SiO2 Catalysts for Slurry-Phase Fischer-Tropsch Synthesis

    Directory of Open Access Journals (Sweden)

    Tomohisa Miyazawa

    2015-01-01

    Full Text Available The addition of Ru to Mn and Zr-modified Co/SiO2 catalysts, while applying different preparation orders and loading amounts, was investigated as a means of enhancing the Fischer-Tropsch synthesis reaction. The coimpregnation of Zr/SiO2 with Co, Mn and Ru gave the most attractive catalytic properties. This can be attributed to the higher dispersion of Co metal resulting from the coimpregnation of Co and Mn as well as enhanced reducibility due to the presence of Ru. The addition of a moderate amount of Ru together with the appropriate order of addition affected both the Co reducibility and the catalytic activity, primarily because of increased reducibility. The addition of even 0.1 wt.% Ru resulted in an obvious enhancement of Fischer-Tropsch synthesis activity.

  9. An efficient one-pot two catalyst system in the construction of 2-substituted benzimidazoles: synthesis of benzimidazo[1,2-c]quinazolines.

    Science.gov (United States)

    Cimarelli, Cristina; Di Nicola, Matteo; Diomedi, Simone; Giovannini, Riccardo; Hamprecht, Dieter; Properzi, Roberta; Sorana, Federico; Marcantoni, Enrico

    2015-12-28

    The benzimidazole core is a common moiety in a large number of natural products and pharmacologically active small molecules. The synthesis of novel benzimidazole derivatives remains a main focus in medicinal research. In continuation of the efforts towards Ce(III) catalysts for organic transformations, we observed for the first time the activity of the iodide ion and copper cation in activating CeCl3·7H2O in the selective formation of prototypical 2-substituted benzimidazoles. The one-pot CeCl3·7H2O-CuI catalytic system procedure includes the cyclo-dehydrogenation of aniline Schiff's bases, generated in situ from the condensation of 1,2-phenylenediamine and aldehydes, followed by the oxidation with iodine, which works as a hydrogen sponge. Mild reaction conditions, good to excellent yields, and clean reactions make the procedure a useful contribution to the synthesis of biologically active fused heterocycles containing benzimidazoquinazolines.

  10. Preparation of weak-light-driven TiO2-based catalysts via adsorbed-layer nanoreactor synthesis and enhancement of their photo-degradation performance in seawater

    Science.gov (United States)

    Wang, Ting; Xu, Zhi-yong; Zhu, Yi-chen; Wu, Li-guang; Yuan, Hao-xuan; Li, Chang-chun; Liu, Ya-yu; Cai, Jing

    2017-11-01

    Graphene oxide (GO) was first employed as a support in preparing TiO2 nanoparticles by adsorbed-layer nanoreactor synthesis (ALNS). Both TiO2 crystallization and GO reduction simultaneously occurred during solvothermal treatment with alcohol as a solvent. By transmission electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and photoluminescence spectroscopy, the results showed that TiO2 nanoparticles with less than 10 nm of size distributed very homogeneously on the GO surface. Tight interaction between TiO2 particles and GO surface could effectively inhibit the aggregation of TiO2 particles, during solvothermal treatment for anatase TiO2 formation. Alcohol could also reduce oxygenated functional groups on GO surface after solvothermal treatment. TiO2 particles with small size and the decrease in oxygenated functional groups on the GO surface both caused high separation efficiency of photo-generated charge carriers, thus resulting in high photo-degradation performance of catalysts. Strong phenol adsorption on photocatalyst was key to enhancing photo-degradation efficiency for phenol in seawater. Moreover, the change in catalyst structure was minimal at different temperatures of solvothermal treatment. But, the degradation rate and efficiency for phenol in seawater were obviously enhanced because of the sensitive structure-activity relationship of catalysts under weak-light irradiation.

  11. Selective and eco-friendly procedures for the synthesis of benzimidazole derivatives. The role of the Er(OTf)3 catalyst in the reaction selectivity.

    Science.gov (United States)

    Herrera Cano, Natividad; Uranga, Jorge G; Nardi, Mónica; Procopio, Antonio; Wunderlin, Daniel A; Santiago, Ana N

    2016-01-01

    An improved and greener protocol for the synthesis of benzimidazole derivatives, starting from o -phenylenediamine, with different aldehydes is reported. Double-condensation products were selectively obtained when Er(OTf) 3 was used as the catalyst in the presence of electron-rich aldehydes. Conversely, the formation of mono-condensation products was the preferred path in absence of this catalyst. One of the major advantages of these reactions was the formation of a single product, avoiding extensive isolation and purification of products, which is frequently associated with these reactions. Theoretical calculations helped to understand the different reactivity established for these reactions. Thus, we found that the charge density on the oxygen of the carbonyl group has a significant impact on the reaction pathway. For instance, electron-rich aldehydes better coordinate to the catalyst, which favours the addition of the amine group to the carbonyl group, therefore facilitating the formation of double-condensation products. Reactions with aliphatic or aromatic aldehydes were possible, without using organic solvents and in a one-pot procedure with short reaction time (2-5 min), affording single products in excellent yields (75-99%). This convenient and eco-friendly methodology offers numerous benefits with respect to other protocols reported for similar compounds.

  12. Selective and eco-friendly procedures for the synthesis of benzimidazole derivatives. The role of the Er(OTf3 catalyst in the reaction selectivity

    Directory of Open Access Journals (Sweden)

    Natividad Herrera Cano

    2016-11-01

    Full Text Available An improved and greener protocol for the synthesis of benzimidazole derivatives, starting from o-phenylenediamine, with different aldehydes is reported. Double-condensation products were selectively obtained when Er(OTf3 was used as the catalyst in the presence of electron-rich aldehydes. Conversely, the formation of mono-condensation products was the preferred path in absence of this catalyst. One of the major advantages of these reactions was the formation of a single product, avoiding extensive isolation and purification of products, which is frequently associated with these reactions.Theoretical calculations helped to understand the different reactivity established for these reactions. Thus, we found that the charge density on the oxygen of the carbonyl group has a significant impact on the reaction pathway. For instance, electron-rich aldehydes better coordinate to the catalyst, which favours the addition of the amine group to the carbonyl group, therefore facilitating the formation of double-condensation products.Reactions with aliphatic or aromatic aldehydes were possible, without using organic solvents and in a one-pot procedure with short reaction time (2–5 min, affording single products in excellent yields (75–99%. This convenient and eco-friendly methodology offers numerous benefits with respect to other protocols reported for similar compounds.

  13. One-pot synthesis of reduced graphene oxide supported PtCuy catalysts with enhanced electro-catalytic activity for the methanol oxidation reaction

    International Nuclear Information System (INIS)

    Peng, Xinglan; Zhao, Yanchun; Chen, Duhong; Fan, Yanfang; Wang, Xiao; Wang, Weili; Tian, Jianniao

    2014-01-01

    The outstanding performance PtCu y (y = 1,2,3) alloy nanoparticles supported on reduced graphene oxide (rGO) have been synthesized by a facile, efficient, one-pot hydrothermal synthesis approach. The as-prepared PtCu y /rGO catalysts are comprehensively characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy. Cyclic voltammetry, CO-stripping voltammetry and chronoamperometry results reveal that the PtCu y /rGO catalysts have higher electro-catalytic activity, more negative onset oxidative potential, more excellent tolerance ability for CO poisoning and enhanced stability for the electro-oxidation of methanol compared to pure Pt/rGO. As far as the as-made PtCu y /rGO catalysts are concerned, the PtCu 2 /rGO exhibits the highest electro-catalytic activity. The mechanism of the promoting effect of Cu on Pt is explained based on the electronic modification effect. The nature of interfacial interactions between the Pt-Cu active metal phase and the rGO supporting materials is crucial to achieving high performance

  14. Synthesis of fatty acid methyl ester from crude jatropha (Jatropha curcas Linnaeus) oil using aluminium oxide modified Mg-Zn heterogeneous catalyst.

    Science.gov (United States)

    Olutoye, M A; Hameed, B H

    2011-06-01

    The synthesis of fatty acid methyl esters (FAME) as a substitute to petroleum diesel was investigated in this study from crude jatropha oil (CJO), a non-edible, low-cost alternative feedstock, using aluminium modified heterogeneous basic oxide (Mg-Zn) catalyst. The transesterification reaction with methanol to methyl esters yielded 94% in 6h with methanol-oil ratio of 11:1, catalyst loading of 8.68 wt.% at 182°C and the properties of CJO fuel produced were determine and found to be comparable to the standards according to ASTM. In the range of experimental parameters investigated, it showed that the catalyst is selective to production of methyl esters from oil with high free fatty acid (FFA) and water content of 7.23% and 3.28%, respectively in a single stage process. Thus, jatropha oil is a promising feedstock for methyl ester production and large scale cultivation will help to reduce the product cost. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. A novel continuous process for synthesis of carbon nanotubes using iron floating catalyst and MgO particles for CVD of methane in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Sarah; Khodadadi, Abasali [Catalysis and Nanostructured Materials Research Laboratory, School of Chemical Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Mortazavi, Yadollah, E-mail: mortazav@ut.ac.ir [Nanoelectronics Centre of Excellence, University of Tehran, POB 11365-4563, Tehran (Iran, Islamic Republic of)

    2010-02-15

    A novel continuous process is used for production of carbon nanotubes (CNTs) by catalytic chemical vapor deposition (CVD) of methane on iron floating catalyst in situ deposited on MgO in a fluidized bed reactor. In the hot zone of the reactor, sublimed ferrocene vapors were contacted with MgO powder fluidized by methane feed to produce Fe/MgO catalyst in situ. An annular tube was used to enhance the ferrocene and MgO contacting efficiency. Multi-wall as well as single-wall CNTs was grown on the Fe/MgO catalyst while falling down the reactor. The CNTs were continuously collected at the bottom of the reactor, only when MgO powder was used. The annular tube enhanced the contacting efficiency and improved both the quality and quantity of CNTs. The SEM and TEM micrographs of the products reveal that the CNTs are mostly entangled bundles with diameters of about 10-20 nm. Raman spectra show that the CNTs have low amount of amorphous/defected carbon with I{sub G}/I{sub D} ratios as high as 10.2 for synthesis at 900 deg. C. The RBM Raman peaks indicate formation of single-walled carbon nanotubes (SWNTs) of 1.0-1.2 nm diameter.

  16. Oxidation catalyst

    Science.gov (United States)

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  17. Synthesis of K2O/Zeolite catalysts by KOH impregnation for biodiesel production from waste frying oil

    Science.gov (United States)

    Fitriana, N.; Husin, H.; Yanti, D.; Pontas, K.; Alam, P. N.; Ridho, M.; Iskandar

    2018-03-01

    K2O/Zeolite compounds were successfully synthesized using KOH as starting material and natural zeolite as support. The catalysts were calcined at 500°C for 3 h and then characterized by X-Ray Diffractometer (XRD) and Scanning Electron Microscopy (SEM). The SEM images reveal that the zeolite and K2O/zeolite particles are irregular in shape (100 to 400 nm). The independent variables were impregnated amounts of KOH (15 - 25%), catalyst to oil ratios of 1.0 - 6.0 wt.%, and reaction time of 2 h. The highest biodiesel yield of 95% was produced from the reaction with 2.1 wt.% catalyst of 25% KOH impregnated. The properties of produced biodiesel complied with SNI. The catalytic stability test showed that the 25% KOH impregnated catalyst was stable.

  18. A Green Synthesis of Xanthenone Derivatives in Aqueous Media Using TiO2-CNTs Nanocomposite as an Eco-Friendly and Re-Usable Catalyst.

    Science.gov (United States)

    Samani, Amir; Abdolmohammadi, Shahrzad; Otaredi-Kashani, Asieh

    2018-01-01

    The xanthene (dibenzopyran) framework constitutes the core structure of many biologically active compounds, that they have been of interest because of their pharmacological activities like antiviral, antibacterial, anti-inflammatory, and CCR1 antagonist. As heterogeneous catalysts offer several advantages over homogeneous catalysts, the performance of reactions on the surface of nanosized heterogeneous salts has received a great deal of interest in recent years. In the area of nanosized heterogeneous catalysts there is a noticeable range of reactions that are catalyzed efficiently by TiO2 NPs. Moreover, carbon nanotubes (CNTs) as a support can be used to obtain nanoparticles with modified morphology, structural, chemical, electrical, and optical properties. The catalytic activity of titanium dioxide supported on carbon nanotubes has been greatly improved. The present methodology focus on the synthesis of 7,7-dimethyl-10-aryl- 6,7,8,10-tetrahydro-9H-[1,3]dioxolo[4,5-b]xanthen-9-ones, through a condensation reaction of dimedone, aromatic aldehydes and 3,4-methylenedioxyphenol, using a catalytic amount of TiO2- CNTs nanocomposite (15 mol%) at 80 ˚C in aqueous media, within 60-90 min. The TiO2-CNTs nanocomposite was also prepared by a known simple sonochemical method. A series of 7,7-dimethyl-10-aryl-6,7,8,10-tetrahydro-9H-[1,3]dioxolo[4,5-b]xanthen-9-ones were successfully synthesized in high yields (92-98%). All synthesized compounds were well characterized by their satisfactory elemental analyses, IR, 1H and 13C NMR spectroscopy. The synthesized catalyst was fully characterized by SEM, TEM, XRD, and EDX techniques. In summary, this investigation constitutes a novel and efficient route for the synthesis of 7,7-dimethyl-10-aryl-6,7,8,10-tetrahydro-9H-[1,3]dioxolo[4,5-b]xanthen-9-ones in high yields, by a three-component reaction of dimedone, aromatic aldehydes and 3,4-methylenedioxyphenol in water and in the presence of the TiO2-CNTs nanocomposite as a green

  19. Synthesis of carbonate esters by carboxymethylation using NaAlO2 as a highly active heterogeneous catalyst

    OpenAIRE

    Ramesh, Sreerangappa; Indukuri, Kiran; Riant, Olivier; Debecker, Damien

    2018-01-01

    Sodium aluminate is presented as a highly active heterogeneous catalyst able to convert a range of alcohols into the corresponding mixed carbonate esters, in high yield and under green conditions. The reaction is carried out using dimethyl carbonate both as a reactant and solvent, at 90°C. Allylic, aliphatic and aromatic alcohols are converted in good yields. The solid catalyst is shown to be truly heterogeneous, resistant to leaching, and recyclable.

  20. Enhancement of biodiesel synthesis from soybean oil by potassium fluoride modification of a calcium magnesium oxides catalyst.

    Science.gov (United States)

    Fan, Mingming; Zhang, Pingbo; Ma, Qinke

    2012-01-01

    Transesterification of soybean oil with methanol was carried out in the presence of CaO-MgO and KF-modified CaO-MgO catalysts at atmospheric pressure. While the methyl ester yield for the CaO-MgO catalyst with a ratio of 8:2 (CaO:MgO) was 63.6%, it was 97.9% for the KF-modified catalyst at a 2% catalyst to the reactants (methanol/oil mixture) weight ratio, a temperature of 65 °C, a methanol-soybean oil ratio of 9:1 and a reaction time of 2.5 h. The KF/CaO-MgO catalyst still yielded 86.7% after four successive uses. The catalytic performance of the KF/CaO-MgO catalyst was attributed to the formation of active KCaF(3) and K(2)MgF(4) centers. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Synthesis of Co/MCM-41catalysts and characterization by XRD, EDX, DTA/TG, SEM and TEM

    International Nuclear Information System (INIS)

    Sousa, B.V.; Rodrigues, M.G.F.

    2009-01-01

    Full text: In this work, molecular sieve MCM-41 was prepared as well as the Co/MCM-41 catalyst, via humid impregnation with concentration of 5 wt.% and 10 wt.% Co/MCM- 41. The attainment of the mesoporous molecular sieve, Si-MCM-41, was confirmed by the x-ray diffractogram. It was verified that after the calcination all the bromine (Br) was removed indicating that the calcination process removed all surfactant in the mesoporous structure. XRD and EDX analyses indicated that cobalt was found in the form of Co3O2 in the Co/MCM-41 catalysts. The diffraction standards showed that the impregnation and calcination processes caused changes in the structure only for catalyst with 10 wt.% Co/MCM-41. The DTA/TG curves showed that cobalt nitrate was totally decomposed on the MCM-41. From the images of SEM, it was possible to observe that the Co/MCM-41 catalysts were composed by clusters of small crystals. The images obtained from TEM showed clearly the presence of metal cobalt particles in a well dispersed form for catalyst with 5 wt.% Co/MCM41, except for the catalyst with 10 wt.% Co/MCM41. (author)

  2. Synthesis of highly efficient Mn2O3 catalysts for CO oxidation derived from Mn-MIL-100

    Science.gov (United States)

    Zhang, Xiaodong; Li, Hongxin; Hou, Fulin; Yang, Yang; Dong, Han; Liu, Ning; Wang, Yuxin; Cui, Lifeng

    2017-07-01

    In this work, metal-organic frameworks (MOFs) Mn-MIL-100 were first prepared, which were next used as templates to obtain the irregular porous Mn2O3 cubes through calcination with air at different temperature. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), H2-temperature program reduction (H2-TPR) and X-ray photoelectron spectroscopic (XPS). The catalytic activity for CO oxidation over Mn2O3 catalysts was investigated. It was found that calcination temperature had a strong effect on the structure and catalytic activity of Mn2O3 catalyst. Mn2O3 catalyst obtained by calcined at 700 °C (Mn2O3-700) showed a smaller specific surface area, but displayed a high catalytic activity and excellent stability with a complete CO conversion temperature (T98) of 240 °C, which was attributed to the unique structure, a high quantity of surface active oxygen species, smaller particle size, oxygen vacancies and good low temperature reduction behavior. The effect of water vapor on catalytic activity was also examined. The introduction of water vapor to the feedstock induced a positive effect on CO oxidation over Mn2O3-700 catalyst. Furthermore, no obvious drop is observed in activity over catalysts even in the presence of water vapor during 48 h.

  3. Metal chloride hydrates as Lewis acid catalysts in multicomponent synthesis of 2,4,5-triarylimidazoles or 2,4,5-triaryloxazoles

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Marcelo V. [Departamento de Engenharia de Processos, Fundacao de Ciencia e Tecnologia, Cachoeirinha, RS (Brazil); Russowsky, Dennis, E-mail: dennis@iq.ufrgs.br [Laboratorio de Sinteses Organicas, Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS (Brazil); Ruthner, Marcelo M.; Fontoura, Luiz A.M. [Curso de Quimica, Universidade Luterana do Brasil, Canoas, RS (Brazil)

    2012-07-01

    A series of nine metal chloride hydrates (ZnCl{sub 2}.2H{sub 2}O, SnCl{sub 2}.2H{sub 2}O, CdCl{sub 2}.2H{sub 2}O, MnCl{sub 2}.4H{sub 2}O, CoCl{sub 2}.6H{sub 2}O, SrCl{sub 2}.6H{sub 2}O, NiCl{sub 2}.6H{sub 2}O, CrCl{sub 3}.6H{sub 2}O and CeCl{sub 3}.7H{sub 2}O) was investigated as mild and inexpensive Lewis acid catalysts to promote the multicomponent synthesis of triarylimidazoles. Reactions starting from benzil showed the best results when SnCl{sub 2}.2H{sub 2}O was used, while for benzoin as the starting material, CeCl{sub 3}.7H{sub 2}O was more efficient. All reactions were performed in EtOH as solvent. These catalysts were also successfully employed in the synthesis of triaryloxazoles. (author)

  4. Template-Assisted Wet-Combustion Synthesis of Fibrous Nickel-Based Catalyst for Carbon Dioxide Methanation and Methane Steam Reforming.

    Science.gov (United States)

    Aghayan, M; Potemkin, D I; Rubio-Marcos, F; Uskov, S I; Snytnikov, P V; Hussainova, I

    2017-12-20

    Efficient capture and recycling of CO 2 enable not only prevention of global warming but also the supply of useful low-carbon fuels. The catalytic conversion of CO 2 into an organic compound is a promising recycling approach which opens new concepts and opportunities for catalytic and industrial development. Here we report about template-assisted wet-combustion synthesis of a one-dimensional nickel-based catalyst for carbon dioxide methanation and methane steam reforming. Because of a high temperature achieved in a short time during reaction and a large amount of evolved gases, the wet-combustion synthesis yields homogeneously precipitated nanoparticles of NiO with average particle size of 4 nm on alumina nanofibers covered with a NiAl 2 O 4 nanolayer. The as-synthesized core-shell structured fibers exhibit outstanding activity in steam reforming of methane and sufficient activity in carbon dioxide methanation with 100% selectivity toward methane formation. The as-synthesized catalyst shows stable operation under the reaction conditions for at least 50 h.

  5. Theoretical study of methanol synthesis from CO2 and CO hydrogenation on the surface of ZrO2 supported In2O3 catalyst

    Science.gov (United States)

    Dou, Maobin; Zhang, Minhua; Chen, Yifei; Yu, Yingzhe

    2018-06-01

    The interactions between ZrO2 support and In2O3 catalyst play pivotal role in the catalytic conversion of CO2 to methanol. Herein, a density functional theory study has been conducted to research the mechanism of methanol synthesis from CO2 and CO hydrogenation on the defective ZrO2 supported In2O3(110) surface (D surface). The calculations reveal that methanol is produced mainly via the HCOO reaction pathway from CO2 hydrogenation on D surface, and the hydrogenation of HCOO to form H2COO species with an activation barrier of 1.21 eV plays the rate determining step for the HCOO reaction pathway. The direct dissociation of CO2 to CO on D surface is kinetically and energetically prohibited. Methanol synthesis from CO hydrogenation on D surface is much facile comparing with the elementary steps involved in CO2 hydrogenation. The rate determining step of CO hydrogenation to methanol is the formation of H3CO species on the vacancy site with a barrier of 0.51 eV. ZrO2 support has significant effect on the suppressing of the dissociation of CO2 and stabilization of H2COO species on the surface of In2O3 catalyst.

  6. Green Synthesis of Cationic Polyacrylamide Composite Catalyzed by An Ecologically Catalyst Clay Called Maghnite-H+ (Algerian MMT Under Microwave Irradiation.

    Directory of Open Access Journals (Sweden)

    Rahmouni Abdelkader

    2016-08-01

    Full Text Available In this study, a novel green cationic hydrogel of cationic polyacrylamide composite have been prepared and investigated. The synthesis of green cationic polyacrylamide composite was evaluated for its solubility in water. The reactions were performed using acrylamide monomer, solvent, catalyst (clay fin called maghnite and solution of  H2SO4 (0.25 M, with the system under microwave irradiation (160 ºC for 4 min. Major factors affecting the polymerization reaction were studied with a view to discover appropriate conditions for preparation of the composite. The cationic polyacrylamide obtained is the subject of future studies of modification and transformation. The resulting polymer has been characterized by a variety of characterization techniques, such as: Fourier Transform Infrared Spectra and 1H NMR spectra.  Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th June 2015; Revised: 2nd September 2015; Accepted: 5th January 2016 How to Cite: Abdelkader, R., Mohammed, B. (2016. Green Synthesis of Cationic Polyacrylamide Composite Catalyzed by An Ecologically  Catalyst Clay Called Maghnite-H+ (Algerian MMT Under Microwave Irradiation. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (2: 170-175 (doi:10.9767/bcrec.11.2.543.170-175 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.2.543.170-175

  7. Sustainable Applications of Nano-Catalysts and Alternative Methods in the Greener Synthesis and Transformations of Chemical

    Science.gov (United States)

    The presentation summarizes our sustainable chemical synthesis activity involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions.1 The synthesis of heterocyclic compounds, coupling reactions, and a var...

  8. Sustainable Biomimetic Approach to Nanomaterials and Applications of Nano-Catalysts in Green Synthesis and Environmental Remediation.

    Science.gov (United States)

    The presentation summarizes our sustainable chemical synthesis activity involving benign alternatives, such as the use of supported reagents, and greener reaction medium in aqueous or solvent-free conditions. The synthesis of heterocyclic compounds, coupling reactions, and a vari...

  9. Ultrasound assisted two-stage biodiesel synthesis from non-edible Schleichera triguga oil using heterogeneous catalyst: Kinetics and thermodynamic analysis.

    Science.gov (United States)

    Sarve, Antaram N; Varma, Mahesh N; Sonawane, Shriram S

    2016-03-01

    Present work deals with the ultrasound-assisted biodiesel production from low cost, substantial acid value kusum (Schleichera triguga) oil using a two-step method of esterification in presence of acid (H2SO4) catalyst followed by transesterification using a basic heterogeneous barium hydroxide (Ba(OH)2) catalyst. The initial acid value of kusum oil was reduced from 21.65 to 0.84 mg of KOH/g of oil, by acid catalyzed esterification with 4:1 methanol to oil molar ratio, catalyst concentration 1% (v/v), ultrasonic irradiation time 20 min at 40 °C. Then, Ba(OH)2 concentration of 3% (w/w), methanol to oil molar ratio of 9:1, ultrasonic irradiation time of 80 min, and temperature of 50 °C was found to be the optimum conditions for transesterification step and triglyceride conversion of 96.8% (wt) was achieved. This paper also examined the kinetics as well as the evaluation of thermodynamic parameters for both esterification and transesterification reactions. The lower value of activation energy and higher values of kinetic constants indicated a fast rate of reaction, which could be attributed to the physical effect of emulsification, in which the microturbulence generated due to radial motion of bubbles, creates an intimate mixing of the immiscible reactants causing the increase in the interfacial area, giving faster reaction kinetics. The positive values of Gibbs-free energy (ΔG), enthalpy (ΔH) and negative value of entropy (ΔS) revealed that both the esterification and transesterification were non-spontaneous, endothermic and endergonic reactions. Therefore, the present work has not only established the escalation obtained due to ultrasonication but also exemplified the two-step approach for synthesis of biodiesel from non-edible kusum oil based on the use of heterogeneous catalyst for the transesterification step. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Effect of CO Concentration on the α-Value of Plasma-Synthesized Co/C Catalyst in Fischer-Tropsch Synthesis

    Directory of Open Access Journals (Sweden)

    James Aluha

    2017-02-01

    Full Text Available A plasma-synthesized cobalt catalyst supported on carbon (Co/C was tested for Fischer-Tropsch synthesis (FTS in a 3-phase continuously-stirred tank slurry reactor (3-φ-CSTSR operated isothermally at 220 °C (493 K, and 2 MPa pressure. Initial syngas feed stream of H2:CO ratio = 2 with molar composition of 0.6 L/L (60 vol % H2 and 0.3 L/L (30 vol % CO, balanced in 0.1 L/L (10 vol % Ar was used, flowing at hourly space velocity (GHSV of 3600 cm3·h−1·g−1 of catalyst. Similarly, other syngas feed compositions of H2:CO ratio = 1.5 and 1.0 were used. Results showed ~40% CO conversion with early catalyst selectivity inclined towards formation of gasoline (C4–C12 and diesel (C13–C20 fractions. With prolonged time-on-stream (TOS, catalyst selectivity escalated towards the heavier molecular-weight fractions such as waxes (C21+. The catalyst’s α-value, which signifies the probability of the hydrocarbon chain growth was empirically determined to be in the range of 0.85–0.87 (at H2:CO ratio = 2, demonstrating prevalence of the hydrocarbon-chain propagation, with particular predisposition for wax production. The inhibiting CO effect towards FTS was noted at molar H2:CO ratio of 1.0 and 1.5, giving only ~10% and ~20% CO conversion respectively, although with a high α-value of 0.93 in both cases, which showed predominant production of the heavier molecular weight fractions.

  11. Synthesis of subnanometer-diameter vertically aligned single-walled carbon nanotubes with copper-anchored cobalt catalysts

    Science.gov (United States)

    Cui, Kehang; Kumamoto, Akihito; Xiang, Rong; An, Hua; Wang, Benjamin; Inoue, Taiki; Chiashi, Shohei; Ikuhara, Yuichi; Maruyama, Shigeo

    2016-01-01

    We synthesize vertically aligned single-walled carbon nanotubes (VA-SWNTs) with subnanometer diameters on quartz (and SiO2/Si) substrates by alcohol CVD using Cu-anchored Co catalysts. The uniform VA-SWNTs with a nanotube diameter of 1 nm are synthesized at a CVD temperature of 800 °C and have a thickness of several tens of μm. The diameter of SWNTs was reduced to 0.75 nm at 650 °C with the G/D ratio maintained above 24. Scanning transmission electron microscopy energy-dispersive X-ray spectroscopy (EDS-STEM) and high angle annular dark field (HAADF-STEM) imaging of the Co/Cu bimetallic catalyst system showed that Co catalysts were captured and anchored by adjacent Cu nanoparticles, and thus were prevented from coalescing into a larger size, which contributed to the small diameter of SWNTs. The correlation between the catalyst size and the SWNT diameter was experimentally clarified. The subnanometer-diameter and high-quality SWNTs are expected to pave the way to replace silicon for next-generation optoelectronic and photovoltaic devices.We synthesize vertically aligned single-walled carbon nanotubes (VA-SWNTs) with subnanometer diameters on quartz (and SiO2/Si) substrates by alcohol CVD using Cu-anchored Co catalysts. The uniform VA-SWNTs with a nanotube diameter of 1 nm are synthesized at a CVD temperature of 800 °C and have a thickness of several tens of μm. The diameter of SWNTs was reduced to 0.75 nm at 650 °C with the G/D ratio maintained above 24. Scanning transmission electron microscopy energy-dispersive X-ray spectroscopy (EDS-STEM) and high angle annular dark field (HAADF-STEM) imaging of the Co/Cu bimetallic catalyst system showed that Co catalysts were captured and anchored by adjacent Cu nanoparticles, and thus were prevented from coalescing into a larger size, which contributed to the small diameter of SWNTs. The correlation between the catalyst size and the SWNT diameter was experimentally clarified. The subnanometer-diameter and high

  12. Facile synthesis of a platinum-lead oxide nanocomposite catalyst with high activity and durability for ethanol electrooxidation.

    Science.gov (United States)

    Yang, Wei-Hua; Wang, Hong-Hui; Chen, De-Hao; Zhou, Zhi-You; Sun, Shi-Gang

    2012-12-21

    Aimed at searching for highly active and stable nano-scale Pt-based catalysts that can improve significantly the energy conversion efficiency of direct ethanol fuel cells (DEFCs), a novel Pt-PbO(x) nanocomposite (Pt-PbO(x) NC) catalyst with a mean size of 3.23 nm was synthesized through a simple wet chemistry method without using a surfactant, organometallic precursors and high temperature. Electrocatalytic tests demonstrated that the as-prepared Pt-PbO(x) NC catalyst possesses a much higher catalytic activity and a longer durability than Pt nanoparticles (nm-Pt) and commercial Pt black catalysts for ethanol electrooxidation. For instance, Pt-PbO(x) NC showed an onset potential that was 30 mV and 44 mV less positive, together with a peak current density 1.7 and 2.6 times higher than those observed for nm-Pt and Pt black catalysts in the cyclic voltammogram tests. The ratio of current densities per unit Pt mass on Pt-PbO(x) NC, nm-Pt and Pt black catalysts is 27.3 : 3.4 : 1 for the long-term (2 hours) chronoamperometric experiments measured at -0.4 V (vs. SCE). In situ FTIR spectroscopic studies revealed that the activity of breaking C-C bonds of ethanol of the Pt-PbO(x) NC is as high as 5.17 times that of the nm-Pt, which illustrates a high efficiency of ethanol oxidation to CO(2) on the as-prepared Pt-PbO(x) NC catalyst.

  13. Synthesis and characterization of nanometal-ordered mesoporous carbon composites as heterogeneous catalysts for electrooxidation of aniline

    International Nuclear Information System (INIS)

    Duan, Xiaoyue; Chen, Yawen; Liu, Xinyue; Chang, Limin

    2017-01-01

    Highlights: •NM-OMC catalysts were prepared for electrochemical oxidation of aniline. •The oxidation of aniline was studied with NM-OMC catalysts suspended in solution. •The Cu-OMC exhibited the highest catalytic activity for aniline degradation. •The mineralization current efficiency was improved by 2 times with Cu-OMC catalyst. •An electrochemical mineralization pathway of aniline was proposed. -- Abstract: The Cu, Co and Ni nanometal embedded ordered mesoporous carbons (NM-OMCs) were fabricated by a soft-template method using phenol/formaldehyde as carbon source and triblock copolymer F127 as template agent. The morphology, structure, surface physicochemical properties and pore structure of the NM-OMCs were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption isotherms. Their potential application to the electrocatalytic degradation of aniline was investigated using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and ·OH radicals generation test. Furthermore, the electrochemical oxidation process of aniline was also investigated in the presence of the OMC-based catalyst particles suspended in a Na 2 SO 4 solution using a PbO 2 anode. Results revealed that the NM-OMCs inherited the ordered mesostructure of pristine OMC and the metal nanoparticles (Cu, Co or Ni) were embedded in the carbon framework. The Cu-OMC exhibited significantly higher catalytic activity than OMC and other NM-OMCs for the electrooxidation of aniline. In electrochemical oxidation process of aniline, nearly all of aniline could be degraded after 120 min of electrolysis with Cu-OMC particles as catalyst, while 89%, 92%, and 97% with OMC, Co-OMC and Ni-OMC catalysts, respectively, obviously higher than 76% of electrochemical oxidation without assistance of catalysts. After

  14. Controllable synthesis of carbon nanotubes by changing the Mo content in bimetallic Fe-Mo/MgO catalyst

    International Nuclear Information System (INIS)

    Xu Xiangju; Huang Shaoming; Yang Zhi; Zou Chao; Jiang Junfan; Shang Zhijie

    2011-01-01

    Research highlights: → Increasing the Mo content in the Fe-Mo/MgO catalysts resulted in an increase in wall number, diameter and growth yield of carbon nanotubes. → The Fe interacts with MgO to form complex (MgO) x (FeO) 1-x (0 4 and relative large metal Mo particles can be generated after reduction. → The avalanche-like reduction of MgMoO 4 makes the catalyst particles to be small thus enhances the utilize efficiency of Fe nanoparticles. - Abstract: A series of Fe-Mo/MgO catalysts with different Mo content were prepared by combustion method and used as catalysts for carbon nanotube (CNT) growth. Transmission electron microscopy studies of the nanotubes show that the number of the CNT walls and the CNT diameters increase with the increasing of Mo content in the bimetallic catalyst. The growth yield determined by thermogravimetric analysis also follows the trend: the higher the Mo content, the higher the yield of the CNTs. However, the increase of Mo content leads to the lower degree of graphitization of CNTs. A comparative study on the morphology and catalytic functions of Fe/MgO, Mo/MgO and Fe-Mo/MgO catalysts was carried out by scanning electron microscopy and X-ray diffraction. It is found that the Fe interacts with MgO to form complexes and is then dispersed into the MgO support uniformly, resulting in very small Fe nanoparticles after reduction. The Mo interacts with MgO to form stoichiometry compound MgMoO 4 and relative large metal Mo particles can be generated after reduction. High yield CNTs with small diameter can be generated from Fe-Mo/MgO because the avalanche-like reduction of MgMoO 4 makes the catalyst particles to be small thus enhances the utilize efficiency of Fe nanoparticles.

  15. Synthesis of the catalyst

    Indian Academy of Sciences (India)

    Admin

    ... to stop the reaction and washed with 60% ethanol until neutrality by successive centrifugations ... The obtained solid was centrifuged and washed with copious amounts of distilled .... [1-(4-Bromo-phenyl)-1H-[1,2,3]triazol-4-yl]-methanol (3l).

  16. Synthesis of vertical MnO_2 wire arrays on hemp-derived carbon for efficient and robust green catalysts

    International Nuclear Information System (INIS)

    Yang, MinHo; Kim, Dong Seok; Sim, Jae-Wook; Jeong, Jae-Min; Kim, Do Hyun; Choi, Jae Hyung; Kim, Jinsoo; Kim, Seung-Soo; Choi, Bong Gill

    2017-01-01

    Highlights: • The three-dimensional nanocomposites based on vertical MnO_2 array on hemp-derived carbon (HDC) were prepared by hydrothermal method. • The 3D v-MnO_2/HDC nanocomposites showed well-defined porous nature with a high specific surface area of 382.3 m"2 g"−"1. • PET glycolysis was performed using the 3D v-MnO_2/HDC nanocomposites as a catalyst, leading to efficient catalytic performance. - Abstract: Three-dimensional (3D) carbon materials derived from waste biomass have been attracted increasing attention in catalysis and materials science because of their great potential of catalyst supports with respect to multi-functionality, unique structures, high surface area, and low cost. Here, we present a facile and efficient way for preparing 3D heterogeneous catalysts based on vertical MnO_2 wires deposited on hemp-derived 3D porous carbon. The 3D porous carbon materials are fabricated by carbonization and activation processes using hemp (Cannabis Sttiva L.). These 3D porous carbon materials are employed as catalyst supports for direct deposition of vertical MnO_2 wires using a one-step hydrothermal method. The XRD and XPS results reveal the crystalline structure of α-MnO_2 wires. The resultant composites are further employed as a catalyst for glycolysis of poly(ethylene terephthalate) (PET) with high conversion yield of 98%, which is expected to be expressly profitable for plastics recycling industry.

  17. A novel method for synthesis of phosphomolybdic acid-modified Pd/C catalysts for oxygen reduction reaction

    Science.gov (United States)

    Zhu, Mingyuan; Gao, Xiaoling; Luo, Guangqin; Dai, Bin

    2013-03-01

    This manuscript reports a convenient method for immobilizing phosphomolybdic acid (HPMo) on polyaniline (PAN-) functionalized carbon supports. The obtained HPMo-PAN-C sample is used as the support to prepare a Pd/HPMo-PAN-C catalyst. The samples are characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and X-ray diffraction analysis. The results suggest that HPMo retains its Keggin structure and that the presence of HPMo reduces the average particle size of the Pd nano-particles in the obtained Pd/HPMo-PAN-C catalyst. Electro-chemical measurements in 0.5 M HClO4 solution reveal that the Pd/HPMo-PAN-C catalyst has higher catalytic activity for oxygen reduction reactions than does a Pd/C catalyst prepared using a similar procedure. The stability of the Pd/HPMo-PAN-C catalyst is evaluated by multiple-cycle voltammetry techniques; the mass catalytic activity decreases by only 10% after 100 scanning cycles.

  18. Synthesis of a highly active carbon-supported Ir-V/C catalyst for the hydrogen oxidation reaction in PEMFC

    International Nuclear Information System (INIS)

    Li Bing; Qiao Jinli; Yang Daijun; Zheng Junsheng; Ma Jianxin; Zhang Jiujun; Wang Haijiang

    2009-01-01

    The active, carbon-supported Ir and Ir-V nanoclusters with well-controlled particle size, dispersity, and composition uniformity, have been synthesized via an ethylene glycol method using IrCl 3 and NH 4 VO 3 as the Ir and V precursors. The nanostructured catalysts were characterized by X-ray diffraction and high-resolution transmission electron microscopy. The catalytic activities of these carbon-supported nanoclusters were screened by applying on-line cyclic voltammetry and electrochemical impedance spectroscopy techniques, which were used to characterize the electrochemical properties of fuel cells using several anode Ir/C and Ir-V/C catalysts. It was found that Ir/C and Ir-V/C catalysts affect the performance of electrocatalysts significantly based on the discharge characteristics of the fuel cell. The catalyst Ir-V/C at 40 wt.% displayed the highest catalytic activity to hydrogen oxidation reaction and, therefore, high cell performance is achieved which results in a maximum power density of 563 mW cm -2 at 0.512 V and 70 deg. C in a real H 2 /air fuel cell. This performance is 20% higher as compared to the commercial available Pt/C catalyst. Fuel cell life test at a constant current density of 1000 mA cm -2 in a H 2 /O 2 condition shows good stability of anode Ir-V/C after 100 h of continuous operation.

  19. Development of GREET Catalyst Module

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States); Benavides, Pahola T. [Argonne National Lab. (ANL), Argonne, IL (United States); Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Cronauer, Donald C. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    In this report, we develop energy and material flows for the production of five different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5], Mo/Co/ γ-Al2O3, and Pt/ γ-Al2O3) and two chemicals (olivine, dimethyl ether of polyethylene glycol [DEPG]). These compounds and catalysts are now included in the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET™) catalyst module.

  20. Synthesis and characterization of Pt-Sn-Ni alloys to application as catalysts for direct ethanol fuel cells

    International Nuclear Information System (INIS)

    Silva, E.L. da; Correa, P.S.; Oliveira, E.L. de; Takimi, A.S.; Malfatti, C.F.; Radtke, C.

    2010-01-01

    Direct ethanol fuel cells (DEFCs) have been the focus of recent research due its application in mobile energy sources. In order to obtain the maximum efficiency from these systems, it is necessary the total ethanol oxidation, which implies in C-C bond break. Different catalysts described in literature are employed with this intent. This work consists in studying PtSnNi catalysts supported on carbon Vulcan XC72R, to application in DEFCs. Thus, it was used the impregnation/reduction method, varying the atomic proportion among Pt, Sn and Ni. The alloys were characterized by X-Ray Diffraction, Cyclic Voltammetry and Transmission Microscopy. Preliminary results show that predominant structure on the catalysts is the face centered cubic platinum and the densities currents are dependent on the platinum amount. (author)