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Sample records for boomerang catalyst system

  1. Outcomes of Clinical Application of Boomerang Closure Wire System

    Institute of Scientific and Technical Information of China (English)

    Jian-sheng WU; Wen-bin WEI; Yu-jia WANG; Xin-xia ZHANG; Xue-song HU

    2009-01-01

    Objectives To evaluate the efficacy and safety of clinical application of a novel type of vascular closure device named Boomerang closure wire system (BCWS). Methods BCWSs were used in 288 patients (BCWSs group) for hemostasis after transfernoral coronary angiography (CAG) or percutaneous coronary intervention (PCI). Device suc-cess rate, hemostasis success rate, manual compression time, recumbent time, minor peripheral complication rate, se-vere peripheral complication rate and hospital staying time after procedure were analyzed. Results were compared to those from 300 patients (control group) who received manual compression in our hospital during the same period. Results In BCWS group, device success rate was 97.2 %, hemostasis success rate was 95.1%. Manual compression time in CAG subgroup and PCI subgroup was 7.8 min and 11.2 min, respectively. Recumbent time was 136. 3 min in CAG subgroup, 284.6 min in PCI subgroup. Minor peripheral complication rate was 4.5 %, severe peripheral compli-cation rate was 2.4 %. Hospital-staying time after procedure in CAG group and PCI group was 1.8 d and 6.6 d, re-spectively. Compared to control group, manual compression time, recumbent time and hospital-staying time of BCWSs group had statistical significance; hemostasis success rate, minor peripheral complication rate and severe peripheral complication rate of BCWSs group bad no statistical difference. Conclusions BCWS provides satisfied haemostatic effect. Compared to routine manual compression, BCWS shortens manual compression time, recumbent time and hos-pital staying time.

  2. A comparison of the boomerang wire vascular access management system versus manual compression alone during percutaneous diagnostic and interventional cardiovascular procedures.

    Science.gov (United States)

    Echeverria, Angela; Krajcer, Zvonimir

    2016-01-01

    Vascular closure devices allow for early sheath removal, allowing for earlier patient mobilization The Boomerang vascular access management system does not alter arterial integrity for future interventions Access site complications provide significant morbidity in diagnostic and therapeutic interventions.

  3. Jedan pristup u oceni efektivnosti sistema za zvukometrijsko izviđanje 'Boomerang' / One approach to the evaluation of the effectiveness of the boomerang system for acoustic source localization and identification

    Directory of Open Access Journals (Sweden)

    Miroslav R. Terzić

    2010-07-01

    Full Text Available U radu je prikazan jedan pristup u oceni efektivnosti sistema za zvukometrijsko izviđanje. Sistem za zvukometrijsko izviđanje modelovan je kao sistem masovnog opsluživanja, opisana su stanja sistema, parametri i izveden izraz za određivanje verovatnoće opsluživanja sistema za zvukometrijskao izviđanje, kao kriterijuma za ocenu efektivnosti. / One approach to the evaluation of the effectiveness of a system for acoustic source localization and identification has been shown in this article. The system for acoustic source localization and identification has been presented as a model of mass servicing system. The states of the system as well as its features have been described while the formula for service probability determination has been derived as a criterion for effectiveness evaluation. The introductory part of the article describes the system for acoustic source localization and identification and shows a model for quantity estimation of the function of technical system effectiveness E (t. The system effectiveness represents a probability of system initiation as well as a probability of its successful mission accomplishment on the basis of designed capabilities within the given time period and operational conditions. The basic characteristics of the Boomerang system for acoustic source localization and identification show the system elements and its designed capability to detect, analyse and distribute acoustic source location data. The analytical model for the evaluation of the effectiveness of the Boomerang system for acoustic source localization and identification shows that 'n' stations for acoustic source localization can exchange information with each other using the network link. The system conditions are described and the expression for the determination of service probability as a criterion for system effectiveness evaluation is derived. The evaluation of the effectiveness of the Boomerang system for acoustic source

  4. Boomerang returns unexpectedly

    CERN Document Server

    White, M; Pierpaoli, E; White, Martin; Scott, Douglas; Pierpaol, Elena

    2000-01-01

    Experimental study of the anisotropy in the cosmic microwave background (CMB) is gathering momentum. The eagerly awaited Boomerang results have lived up to expectations. They provide convincing evidence in favor of the standard paradigm: the Universe is close to flat and with primordial fluctuations which are redolent of inflation. Further scrutiny reveals something even more exciting however -- two hints that there may be some unforeseen physical effects. Firstly the primary acoustic peak appears at slightly larger scales than expected. Although this may be explicable through a combination of mundane effects, we suggest it is also prudent to consider the possibility that the Universe might be marginally closed. The other hint is provided by a second peak which appears less prominent than expected. This may indicate one of a number of possibilities, including increased damping length or tilted initial conditions, but also breaking of coherence or features in the initial power spectrum. Further data should tes...

  5. Catalyst systems and uses thereof

    Science.gov (United States)

    Ozkan, Umit S.; Holmgreen, Erik M.; Yung, Matthew M.

    2012-07-24

    A method of carbon monoxide (CO) removal comprises providing an oxidation catalyst comprising cobalt supported on an inorganic oxide. The method further comprises feeding a gaseous stream comprising CO, and oxygen (O.sub.2) to the catalyst system, and removing CO from the gaseous stream by oxidizing the CO to carbon dioxide (CO.sub.2) in the presence of the oxidation catalyst at a temperature between about 20 to about 200.degree. C.

  6. Computational aspects of the smectization process in liquid crystals: An example study of a perfectly aligned two-dimensional hard-boomerang system

    Science.gov (United States)

    Chrzanowska, Agnieszka

    2017-06-01

    A replica method for calculation of smectic liquid crystal properties within the Onsager theory has been presented and applied to an exemplary case of two-dimensional perfectly aligned needlelike boomerangs. The method allows one to consider the complete influence of the interaction terms in contrast to the Fourier expansion method which uses mostly first or second order terms of expansion. The program based on the replica algorithm is able to calculate a single representative layer as an equivalent set of layers, depending on the size of the considered width of the sample integration interval. It predicts successfully smectic density distributions, energies, and layer thicknesses for different types of layer arrangement—of the antiferroelectric or of the smectic A order type. Specific features of the algorithm performance and influence of the numerical accuracy on the physical properties are presented. Future applications of the replica method to freely rotating molecules are discussed.

  7. Catalyst for microelectromechanical systems microreactors

    Science.gov (United States)

    Morse, Jeffrey D.; Sopchak, David A.; Upadhye, Ravindra S.; Reynolds, John G.; Satcher, Joseph H.; Gash, Alex E.

    2010-06-29

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  8. Manufacture of Catalyst Systems for Ammonia Conversion

    Institute of Scientific and Technical Information of China (English)

    GAKH S.V.; SAVENKOV D.A.

    2012-01-01

    Platinum catalyst gauzes have been in use since the moment of development of the process of catalyst oxidation of ammonia for production of nitric acid or hydrocyanic acid.Catalyst gauzes are usually made of platinum or its alloys with rhodium and palladium.These precious metals have remarkable properties that make them ideal catalysts for acceleration of the ammonia/oxygen reaction.In 2008,OJSC "SIC ‘Supermetal’" and Umicore AG&Co.KG launched a production line for Pt-alloy-based catalyst systems to be used for ammonia oxidation in the production of weak nitric acid.Catalyst systems consist of a pack of catalyst gauzes and a pack of catchment gauzes,which are made using flat-bed knitting machines and wire-cloth looms.Today,up-to-date catalyst systems MKSpreciseTM are being manufactured,the basic advantages of which are an individual structure of gauzes and composition of the material,which allows to define precisely the position of each gauze in the catalyst pack,a high activity of the catalyst pack,direct catching of platinum and rhodium in the catalyst system,and a reasonable combination of single- and multilayer types of gauzes.This makes it possible to vary the configuration of the catalyst and select an optimum composition of the system to ensure the maximum efficiency of the ammonia oxidation process.We also produce the catchment systems that allow to find the best decision from the economic point view for each individual case.

  9. The Boomerang Nebula - The Coldest Region of the Universe

    Science.gov (United States)

    Sahai, Raghvendra; Nyman, Lars-Ake

    1997-01-01

    In this letter, we report such observations of the Boomerang Nebula which show it to be a unique object, consisiting of an ultra-cold and extremely massive molecular envolope, expanding at very high speed. The extreeme physical characteristics of the Boomerang Nebula reported here have never been seen before in any AGB or post-AGB object, and should spur new theoretical and obesrvational efforts to understand the nature of the mass-loss processes occurring during later stellar evolution.

  10. Catalyst system of the structured type

    NARCIS (Netherlands)

    Jansen, J.C.; Legein, C.H.; Calis, H.P.A.; Van Bekkum, H.; Gerritsen, A.W.; Van den Bleek, M.

    1994-01-01

    The invention relates to a catalyst system of the structured type, in which a structured support is covered with a layer of molecular sieve crystals and/or modifications thereof. These crystals have substantially the same orientation relative to the support surface. The invention further relates to

  11. Supported catalyst systems and method of making biodiesel products using such catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Manhoe; Yan, Shuli; Salley, Steven O.; Ng, K. Y. Simon

    2015-10-20

    A heterogeneous catalyst system, a method of preparing the catalyst system and a method of forming a biodiesel product via transesterification reactions using the catalyst system is disclosed. The catalyst system according to one aspect of the present disclosure represents a class of supported mixed metal oxides that include at least calcium oxide and another metal oxide deposited on a lanthanum oxide or cerium oxide support. Preferably, the catalysts include CaO--CeO.sub.2ZLa.sub.2O.sub.3 or CaO--La.sub.2O.sub.3/CeO.sub.2. Optionally, the catalyst may further include additional metal oxides, such as CaO--La.sub.2O.sub.3--GdOxZLa.sub.2O.sub.3.

  12. Process of activation of a palladium catalyst system

    Science.gov (United States)

    Sobolevskiy, Anatoly; Rossin, Joseph A.; Knapke, Michael J.

    2011-08-02

    Improved processes for activating a catalyst system used for the reduction of nitrogen oxides are provided. In one embodiment, the catalyst system is activated by passing an activation gas stream having an amount of each of oxygen, water vapor, nitrogen oxides, and hydrogen over the catalyst system and increasing a temperature of the catalyst system to a temperature of at least 180.degree. C. at a heating rate of from 1-20.degree./min. Use of activation processes described herein leads to a catalyst system with superior NOx reduction capabilities.

  13. Alar base reduction: the boomerang-shaped excision.

    Science.gov (United States)

    Foda, Hossam M T

    2011-04-01

    A boomerang-shaped alar base excision is described to narrow the nasal base and correct the excessive alar flare. The boomerang excision combined the external alar wedge resection with an internal vestibular floor excision. The internal excision was inclined 30 to 45 degrees laterally to form the inner limb of the boomerang. The study included 46 patients presenting with wide nasal base and excessive alar flaring. All cases were followed for a mean period of 18 months (range, 8 to 36 months). The laterally oriented vestibular floor excision allowed for maximum preservation of the natural curvature of the alar rim where it meets the nostril floor and upon its closure resulted in a considerable medialization of alar lobule, which significantly reduced the amount of alar flare and the amount of external alar excision needed. This external alar excision measured, on average, 3.8 mm (range, 2 to 8 mm), which is significantly less than that needed when a standard vertical internal excision was used ( P < 0.0001). Such conservative external excisions eliminated the risk of obliterating the natural alar-facial crease, which did not occur in any of our cases. No cases of postoperative bleeding, infection, or vestibular stenosis were encountered. Keloid or hypertrophic scar formation was not encountered; however, dermabrasion of the scars was needed in three (6.5%) cases to eliminate apparent suture track marks. The boomerang alar base excision proved to be a safe and effective technique for narrowing the nasal base and elimination of the excessive flaring and resulted in a natural, well-proportioned nasal base with no obvious scarring. © Thieme Medical Publishers.

  14. General Motors Phase II Catalyst System

    Energy Technology Data Exchange (ETDEWEB)

    Canale, R.P.; Winegarden, S.R.; Carlson, C.R.; Miles, D.L.

    1978-01-01

    Three-way catalysts provide a means of catalytically achieving lower NOx emission levels while maintaining good control of HC and CO emissions. However, very accurate control of air-fuel ratio is necessary. The precise air-fuel ratio control required is accomplished by employing a closed loop fuel metering system in conjunction with an exhaust gas sensor and an electronic control unit. To gain production experience with this type of system, General Motors is introducing it on two 1978 engine families sold in California. One is a 2.5 liter L-4 engine and the other is a 3.8 liter V-6 engine. Closed loop controlled carburetors are used on both systems. The components used on both systems are described and emission and fuel economy results are reviewed.

  15. Multi-stage catalyst systems and uses thereof

    Science.gov (United States)

    Ozkan, Umit S.; Holmgreen, Erik M.; Yung, Matthew M.

    2009-02-10

    Catalyst systems and methods provide benefits in reducing the content of nitrogen oxides in a gaseous stream containing nitric oxide (NO), hydrocarbons, carbon monoxide (CO), and oxygen (O.sub.2). The catalyst system comprises an oxidation catalyst comprising a first metal supported on a first inorganic oxide for catalyzing the oxidation of NO to nitrogen dioxide (NO.sub.2), and a reduction catalyst comprising a second metal supported on a second inorganic oxide for catalyzing the reduction of NO.sub.2 to nitrogen (N.sub.2).

  16. A New Reaction-controlled Phase-transfer Catalyst System

    Institute of Scientific and Technical Information of China (English)

    Ming Qiang LI; Xi Gao JIAN; Gui Mei WANG; Yan YU

    2004-01-01

    A new reaction-controlled phase-transfer catalyst system was designed and synthesized. In this system, heteropolytungstate [C7H7N(CH3)3]9PW9O34 was used for catalytic epoxidation of cyclohexene with H2O2 as the oxidant. The conversion of H2O2 was 100% and the yield of cyclohexene oxide was 87.1% based on cyclohexene. Infrared spectra showed that both fresh catalyst and the recovered catalyst do have completely same absorption peak, indicating the structure of catalyst is very stability and can be recycled.

  17. The cosmic microwave background after MAXIMA and BOOMERANG

    Energy Technology Data Exchange (ETDEWEB)

    Richards, Paul L.

    2000-12-01

    The first release of data from the MAXIMA and BOOMERANG experiments has introduced a new era of precision cosmology. The two data sets are essentially independent, consistent and complementary. In a joint effort by the two teams, the two data sets were combined and then used to test cosmological models and determine values of cosmological constants. These results are available because of the success of bolometric detection techniques. The experimental approach is described with references to the MAXIMA-1 experiment. Important new cosmological experiments at far infrared and millimeter wavelengths require major improvements in bolometric techniques. A new technology, the voltage-biased superconducting bolometer, promises to provide the required experimental power.

  18. Spinning Flight Dynamics of Frisbees, Boomerangs, Samaras, and Skipping Stones

    CERN Document Server

    Lorenz, Ralph D

    2006-01-01

    More frisbees are sold each year than baseballs, basketballs, and footballs combined. Yet these familiar flying objects have subtle and clever aerodynamic and gyrodynamic properties which are only recently being documented by wind tunnel and other studies. In common with other rotating bodies discussed in this readily accessible book, they are typically not treated in textbooks of aeronautics and the literature is scattered in a variety of places. This book develops the theme of disc-wings and spinning aerospace vehicles in parallel. Many readers will have enjoyed these vehicles and their dynamics in recreational settings, so this book will be of wide interest. In addition to spinning objects of various shapes, several exotic manned aircraft with disc platforms have been proposed and prototypes built - these include a Nazi ‘secret weapon’ and the De Havilland Avrocar, also discussed in the book. Boomerangs represent another category of spinning aerodynamic body whose behavior can only be understood by cou...

  19. 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.

  20. Cathodic catalysts in bioelectrochemical systems for energy recovery from wastewater.

    Science.gov (United States)

    Liu, Xian-Wei; Li, Wen-Wei; Yu, Han-Qing

    2014-11-21

    Bioelectrochemical systems (BESs), in which microorganisms are utilized as a self-regenerable catalyst at the anode of an electrochemical cell to directly extract electrical energy from organic matter, have been widely recognized as a promising technology for energy-efficient wastewater treatment or even for net energy generation. However, currently BES performance is constrained by poor cathode reaction kinetics. Thus, there is a strong impetus to improve the cathodic catalysis performance through proper selection and design of catalysts. This review introduces the fundamentals and current development status of various cathodic catalysts (including electrocatalysts, photoelectrocatalysts and bioelectrocatalysts) in BES, identifies their limitations and influential factors, compares their catalytic performances in terms of catalytic efficiency, stability, selectivity, etc., and discusses the possible optimization strategies and future research directions. Special focus is given on the analysis of how the catalytic performance of different catalysts can be improved by fine tuning their physicochemical or physiological properties.

  1. Catalysts for portable, solid state hydrogen genration systems

    Science.gov (United States)

    Gabl, Jason Robert

    Hydrogen and air powered proton exchange membrane fuel cells are a potential alternative to batteries. In portable power systems, the design requirements often focus on cost efficiency, energy density, storability, as well as safety. Ammonia borane (AB), a chemical hydride containing 19.6 wt. % hydrogen, has a high hydrogen capacity and is a stable and non-toxic candidate for storing hydrogen in portable systems. Throughout this work, Department of Energy guidelines for low power portable hydrogen power systems were used as a baseline and comparison with commercially available systems. In order to make this comparison, the system parameters of a system using AB hydrolysis were estimated by developing capacity and cost correlations from the commercial systems and applying them to this work. Supporting experiments were designed to evaluate a system that would use a premixed solid storage bed of AB and a catalyst. This configuration would only require a user input of water in order to initiate the hydrogen production. Using ammonia borane hydrolysis, the hydrogen yield is ˜9 wt. %, when all reactants are considered. In addition to the simplicity of initiating the reaction, hydrolysis of AB has the advantage of suppressing the production of some toxic borazines that are present when AB is thermally decomposed. However, ammonia gas will be formed and this problem must be addressed, as ammonia is damaging to PEM fuel cells. The catalyst focused on throughout this work was Amberlyst - 15; an ion exchange resin with an acid capacity of 4.7 eq/kg and ammonia adsorbent. At less than 0.30/g, this is a cost effective alternative to precious metal catalysts. The testing with this catalyst was compared to a traditional catalyst in literature, 20% platinum in carbon, costing more than 40/g. The Amberlyst catalyst was found to reduce the formation of ammonia in the gas products from ˜3.71 wt. % with the Pt/C catalyst to 90 % to cost effective, energy dense, and safe option for

  2. Methods of producing epoxides from alkenes using a two-component catalyst system

    Science.gov (United States)

    Kung, Mayfair C.; Kung, Harold H.; Jiang, Jian

    2013-07-09

    Methods for the epoxidation of alkenes are provided. The methods include the steps of exposing the alkene to a two-component catalyst system in an aqueous solution in the presence of carbon monoxide and molecular oxygen under conditions in which the alkene is epoxidized. The two-component catalyst system comprises a first catalyst that generates peroxides or peroxy intermediates during oxidation of CO with molecular oxygen and a second catalyst that catalyzes the epoxidation of the alkene using the peroxides or peroxy intermediates. A catalyst system composed of particles of suspended gold and titanium silicalite is one example of a suitable two-component catalyst system.

  3. Dehalogenation of Aryl Halides Catalyzed by Montmorillonite Immobilized Bimetal Catalyst in Aqueous System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel bisupported bimetal catalyst PVP-PdCl2-FeSO4/Al-Mont-PEG600 was prepared by immobilization of PVP (poly (N-vinyl-2-pyrrolidone)) supported bimetallic catalyst using alumina pillared inartificial montmorillonite as the carrier. This catalyst has good dehalogenation activity and selectivity to aryl halides-o-chlorotoluene in aqueous system in the presence of phase transfer catalyst (PEG) and sodium formate as hydrogen source. The catalyst also shows good reusability.

  4. Sol-gel based oxidation catalyst and coating system using same

    Science.gov (United States)

    Watkins, Anthony N. (Inventor); Leighty, Bradley D. (Inventor); Oglesby, Donald M. (Inventor); Patry, JoAnne L. (Inventor); Schryer, Jacqueline L. (Inventor)

    2010-01-01

    An oxidation catalyst system is formed by particles of an oxidation catalyst dispersed in a porous sol-gel binder. The oxidation catalyst system can be applied by brush or spray painting while the sol-gel binder is in its sol state.

  5. Palladium catalyst system comprising zwitterion and/or acid-​functionalized ionic liquid

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention concerns a catalyst system in particular a catalyst system comprising Palladium (Pd), a zwitterion and/or an acid-functionalized ionic liquid, and one or more phosphine ligands, wherein the Pd catalyst can be provided by a complex precursor, such as Pd(CH3COO)2, PdCI2, Pd(CH3...

  6. Palladium catalyst system comprising zwitterion and/or acid-functionalized ionic liquid

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention concerns a catalyst system in particular a catalyst system comprising Palladium (Pd), a zwitterion and/or an acid-functionalized ionic liquid, and one or more phosphine ligands, wherein the Pd catalyst can be provided by a complex precursor, such as Pd(CH3COO)2, PdCI2, Pd(CH3...

  7. SO2 oxidation catalyst model systems characterized by thermal methods

    DEFF Research Database (Denmark)

    Hatem, G; Eriksen, Kim Michael; Gaune-Escard, M;

    2002-01-01

    The molten salts M2S2O7 and MHSO4, the binary molten salt Systems M2S2O7-MHSO4 and the molten salt-gas systems M2S2O7 V2O5 and M2S2O7-M2SO4 V2O5 (M = Na, K, Rb, Cs) in O-2, SO2 and At atmospheres have been investigated by thermal methods like calorimetry, Differential Enthalpic Analysis (DEA) and...... to the mechanism Of SO2 oxidation by V2O5 based industrial catalysts....

  8. Photo-oxidation catalysts

    Science.gov (United States)

    Pitts, J. Roland; Liu, Ping; Smith, R. Davis

    2009-07-14

    Photo-oxidation catalysts and methods for cleaning a metal-based catalyst are disclosed. An exemplary catalyst system implementing a photo-oxidation catalyst may comprise a metal-based catalyst, and a photo-oxidation catalyst for cleaning the metal-based catalyst in the presence of light. The exposure to light enables the photo-oxidation catalyst to substantially oxidize absorbed contaminants and reduce accumulation of the contaminants on the metal-based catalyst. Applications are also disclosed.

  9. Novel catalysts and photoelectrochemical system for solar fuel production

    Science.gov (United States)

    Zhang, Yan

    Solar fuel production from abundant raw chemicals such as CO2 and water is highly desired as a clean renewable energy solution for the future. Developing photoelectrochemical cells is viewed as a promising approach to realize this energy conversion and storage process. Efficient and robust oxygen evolution catalyst made from non-precious materials remains a major challenge for such a system. This thesis basically consists of three parts of work, including studies on enhancing the photocatalytic oxygen evolution activity of cobalt-based spinel nanoparticles by manganese3+ substitution, in situ formation of cobalt oxide nanocubanes as highly active catalyst for photocatalytic oxygen evolution reaction, and development of a photoanode-driven photoelectrochemical cell for CO2 reduction with water. The first part of this thesis work devotes efforts in the development and study on cobalt and other transition metal oxide based oxygen evolution catalyst. Photocatalytic oxygen evolution is a critical step for solar fuel production from abundant sources. It poses a significant challenge because it requires an efficient catalyst to bridge the one-electron photon capture process with the four-electron oxygen reaction. Among all the metal oxides, Co3O4 spinel exhibits a high activity as an oxygen evolution catalyst. The results of this work demonstrate that the photocatalytic oxygen evolution activity of Co3O4 spinel can be further enhanced by substituting Co with Mn in the spinel structure. Using a facile hydrothermal approach, Co3O4 spinel nanoparticles as well as Mn-substituted and Ni-substituted Co3O4 spinel nanoparticles with a typical particle size of 5-7 nm were successfully synthesized. The morphology and crystal structures of the as-synthesized nanoparticle catalysts have been carefully examined using various structural characterization techniques, including powder x-ray diffraction (PXRD), transmission electron microscope (TEM), gas adsorption, and x-ray absorption

  10. On the degradation of fuel cell catalyst. From model systems to high surface area catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Arenz, M. [Copenhagen Univ. (Denmark). Dept. of Chemistry

    2010-07-01

    In the presented work, as an alternative accelerated degradation tests in the form of half-cell measurements combined with identical location transmission electron microscopy (IL-TEM){sup 10,} {sup 11} are presented. It is demonstrated that for different catalysts the degradation mechanism can be scrutinized in detail. Thus this approach enables the systematic investigation of fuel cell catalyst degradation in a reduced period of time. (orig.)

  11. Searching for non Gaussian signals in the BOOMERanG 2003 CMB maps

    CERN Document Server

    De Troia, G; Bock, J J; Bond, J R; Borrill, J; Boscaleri, A; Cabella, P; Contaldi, C R; Crill, B P; De Bernardis, P; De Gasperis, G; De Oliveira-Costa, A; Di Stefano, G; Ferreira, P G; Hivon, E; Jaffe, A H; Kisner, T S; Kunz, M; Jones, W C; Lange, A E; Liguori, M; Masi, S; Matarrese, S; Mauskopf, P D; MacTavish, C J; Melchiorri, A; Montroy, T E; Natoli, P; Netterfield, C B; Pascale, E; Piacentini, F; Pogosyan, D; Polenta, G; Prunet, S; Ricciardi, S; Romeo, G; Ruhl, J E; Santini, P; Tegmark, M; Veneziani, M; Vittorio, N

    2007-01-01

    We analyze the BOOMERanG 2003 (B03) 145 GHz temperature map to constrain the amplitude of a non Gaussian, primordial contribution to CMB fluctuations. We perform a pixel space analysis restricted to a portion of the map chosen in view of high sensitivity, very low foreground contamination and tight control of systematic effects. We set up an estimator based on the three Minkowski functionals which relies on high quality simulated data, including non Gaussian CMB maps. We find good agreement with the Gaussian hypothesis and derive the first limits based on BOOMERanG data for the non linear coupling parameter f_NL as -350

  12. Boomerang sign: Clinical significance of transient lesion in splenium of corpus callosum

    Directory of Open Access Journals (Sweden)

    Hardeep Singh Malhotra

    2012-01-01

    Full Text Available Transient signal abnormality in the splenium of corpus callosum on magnetic resonance imaging (MRI is occasionally encountered in clinical practice. It has been reported in various clinical conditions apart from patients with epilepsy. We describe 4 patients with different etiologies presenting with signal changes in the splenium of corpus callosum. They were diagnosed as having progressive myoclonic epilepsy (case 1, localization-related epilepsy (case 2, hemicrania continua (case 3, and postinfectious parkinsonism (case 4. While three patients had complete involvement of the splenium on diffusion-weighted image ("boomerang sign", the patient having hemicrania continua showed semilunar involvement ("mini-boomerang" on T2-weighted and FLAIR image. All the cases had noncontiguous involvement of the splenium. We herein, discuss these cases with transient splenial involvement and stress that such patients do not need aggressive diagnostic and therapeutic interventions. An attempt has been made to review the literature regarding the pathophysiology, etiology, and outcome of such lesions.

  13. Controlling placement of nonspherical (boomerang) colloids in nematic cells with photopatterned director

    Science.gov (United States)

    Peng, Chenhui; Turiv, Taras; Zhang, Rui; Guo, Yubing; Shiyanovskii, Sergij V.; Wei, Qi-Huo; de Pablo, Juan; Lavrentovich, Oleg D.

    2017-01-01

    Placing colloidal particles in predesigned sites represents a major challenge of the current state-of-the-art colloidal science. Nematic liquid crystals with spatially varying director patterns represent a promising approach to achieve a well-controlled placement of colloidal particles thanks to the elastic forces between the particles and the surrounding landscape of molecular orientation. Here we demonstrate how the spatially varying director field can be used to control placement of non-spherical particles of boomerang shape. The boomerang colloids create director distortions of a dipolar symmetry. When a boomerang particle is placed in a periodic splay-bend director pattern, it migrates towards the region of a maximum bend. The behavior is contrasted to that one of spherical particles with normal surface anchoring, which also produce dipolar director distortions, but prefer to compartmentalize into the regions with a maximum splay. The splay-bend periodic landscape thus allows one to spatially separate these two types of particles. By exploring overdamped dynamics of the colloids, we determine elastic driving forces responsible for the preferential placement. Control of colloidal locations through patterned molecular orientation can be explored for future applications in microfluidic, lab on a chip, sensing and sorting devices.

  14. Recyclable hydroformylation catalysts of higher alkenes using immobilized catalysts and two-phase systems

    Energy Technology Data Exchange (ETDEWEB)

    Reek, J.N.H.; Sandee, A.J.; Schreuder Goedheijt, M.; Kamer, P.C.J.; Leeuwen, P.W.N.M. van [Amsterdam Univ. (Netherlands). Inst. of Molecular Chemistry, Homogeneous Catalysis

    2001-03-01

    This article reports on the use of recyclable catalysts, using different concepts, in the hydroformylation of 1-octene employing diphosphine ligands based on the xantene backbone. Amphiphilic diphosphines were developed for the aqueous two-phase catalysis, which spontaneously form aggregates that are remarkably thermostable. The observed TOF's in the hydroformylation of 1-octene using ligands that form vesicles are up to 14 times higher compared to analogue ligands that do not form aggregates. A water-soluble ligand based on the xantene backbone was used to form a stable and recyclable supported aqueous phase catalyst (SAPC). A xanthene-based ligand, N-(3-trimethoxysilane-n-propyl)-4,5-bis(diphenyl-phosphino)-phenoxazine (Siloxantphos) was anchored covalently to a silica support by the sol-gel technique. All concepts demonstrated that the rhodium complexes of these ligands form very selective hydroformylation catalysts producing linear aldehydes. Under similar conditions the activity of the silica-immobilized catalysts is higher than that of the aggregates (by a factor 2) of which the activity is higher than the SAP catalyst (factor 12). (orig.)

  15. Water-gas shift on gold catalysts: catalyst systems and fundamental studies.

    Science.gov (United States)

    Tao, Franklin Feng; Ma, Zhen

    2013-10-07

    Since the pioneering finding by Haruta et al. that small gold nanoparticles on reducible supports can be highly active for low-temperature CO oxidation, the synthesis, characterization, and application of supported gold catalysts have attracted much attention. The water-gas shift reaction (WGSR: CO + H2O = CO2 + H2) is important for removing CO and upgrading the purity of H2 for fuel cell applications, ammonia synthesis, and selective hydrogenation processes. In recent years, much attention has been paid to exploration the possibility of using supported gold nanocatalysts for WGSR and understanding the fundamental aspects related to catalyst deactivation mechanisms, nature of active sites, and reaction mechanisms. Here we summarize recent advances in the development of supported gold catalysts for this reaction and fundamental insights that can be gained, and furnish our assessment on the status of research progress.

  16. Low-temperature NOx reduction processes using combined systems of pulsed corona discharge and catalysts

    Science.gov (United States)

    Kim, H. H.; Takashima, K.; Katsura, S.; Mizuno, A.

    2001-02-01

    In this paper, we will report NOx removal via reduction processes using two types of combined system of pulse corona discharge and catalysts: the single-stage plasma-driven catalyst (PDC) system, and the two-stage plasma-enhanced selective catalytic reduction (PE-SCR) system. Several catalysts, such as γ-alumina catalysts, mechanically mixed catalysts of γ-alumina with BaTiO3 or TiO2, and Co-ZSM-5 were tested. In the PDC system, which is directly activated by the discharge plasma, it was found that the use of additives was necessary to achieve NOx removal by reduction. Removal rates of NO and NOx were linearly increased as the molar ratio of additive to NOx increased. The dependence of NO and NOx removal on the gas hourly space velocity (GHSV) at a fixed specific input energy (SIE) indicates that plasma-induced surface reaction on the catalyst plays an important role in the PDC system. It was found that the optimal GHSV of the PDC system with the γ-alumina catalyst was smaller than 6000 h-1. Mechanical mixing of γ-alumina with BaTiO3 or TiO2 did not enhance NO and NOx removal and γ-alumina alone was found to be the most suitable catalyst. The dielectric constant of the catalyst only influenced the plasma intensity, not the NOx removal. In the PE-SCR system, plasma-treated NOx (mostly NO2) was reduced effectively with NH3 over the Co-ZSM-5 catalyst at a relatively low temperature of 150 °C. Under optimal conditions the energy cost and energy yield were 25 eV/molecule and 21 g-N (kWh)-1, respectively.

  17. Non-Precious Bimetallic Catalysts for Selective Dehydrogenation of an Organic Chemical Hydride System

    KAUST Repository

    Shaikh Ali, Anaam

    2015-07-06

    Methylcyclohexane (MCH)-Toluene (TOL) chemical hydride cycles as a hydrogen carrier system is successful with the selective dehydrogenation reaction of MCH to TOL, which has been achieved only using precious Pt-based catalysts. Herein, we report improved selectivity using non-precious metal nickel-based bimetallic catalysts, where the second metal occupies the unselective step sites.

  18. How to Obtain Computational Completeness in P Systems with One Catalyst

    Directory of Open Access Journals (Sweden)

    Rudolf Freund

    2013-09-01

    Full Text Available Whether P systems with only one catalyst can already be computationally complete, is still an open problem. Here we establish computational completeness by using specific variants of additional control mechanisms. At each step using only multiset rewriting rules from one set of a finite number of sets of multiset rewriting rules allows for obtaining computational completeness with one catalyst and only one membrane. If the targets are used for choosing the multiset of rules to be applied, for getting computational completeness with only one catalyst more than one membrane is needed. If the available sets of rules change periodically with time, computational completeness can be obtained with one catalyst in one membrane. Moreover, we also improve existing computational completeness results for P systems with mobile catalysts and for P systems with membrane creation.

  19. Catalysts, systems and methods to reduce NOX in an exhaust gas stream

    Science.gov (United States)

    Castellano, Christopher R.; Moini, Ahmad; Koermer, Gerald S.; Furbeck, Howard

    2010-07-20

    Catalysts, systems and methods are described to reduce NO.sub.x emissions of an internal combustion engine. In one embodiment, an emissions treatment system for an exhaust stream is provided having an SCR catalyst comprising silver tungstate on an alumina support. The emissions treatment system may be used for the treatment of exhaust streams from diesel engines and lean burn gasoline engines. An emissions treatment system may further comprise an injection device operative to dispense a hydrocarbon reducing agent upstream of the catalyst.

  20. Riesgo de aparición del efecto boomerang en las comunicaciones contra la violencia The Risk of Emergence of Boomerang Effect in Communication against Violence

    Directory of Open Access Journals (Sweden)

    José Antonio Ruiz San Román

    2011-10-01

    Full Text Available Los comportamientos violentos causan inquietud entre los responsables públicos (políticos, educadores, asistentes sociales, asociaciones de madres y padres, etc. que, desde diversos ámbitos, toman medidas que tratan de dar solución al problema de la violencia. La difusión de campañas institucionales de comunicación en contra de la violencia y el fomento de la publicación de noticias relacionadas con sucesos violentos suelen ser algunas de las acciones utilizadas. No obstante, parte de los datos y de la literatura disponible han demostrado que su eficacia no siempre es la esperada e, incluso, dichas acciones pueden llegar a tener efectos contrarios al deseado y reforzar las actitudes de los que piensan que la violencia es necesaria. Se sostiene la hipótesis de que la mayoría de la población asumiría como propios los mensajes contrarios a la violencia. Sin embargo –y esto es la cuestión clave y más problemática– son justo aquellos individuos con mayor propensión a la violencia (precisamente aquellos a quienes deberían dirigirse tales comunicaciones quienes podrían reaccionar ante el mensaje antiviolencia de un modo no deseado. Se da una dramática paradoja: el mensaje antiviolencia podría aumentar la predisposición a desarrollar comportamientos violentos. Estaríamos ante un caso de lo que cierta literatura denomina efecto boomerang. Por último, se señala la necesidad de un estudio detallado sobre determinados efectos de los medios de comunicación (insensibilización, imitación, accesibilidad y reactancia, que podrían ayudar a explicar la aparición de dicho efecto boomerang.Violent behaviors cause concern among people, policy makers, politicians, educators, social workers, parents associations, etc. From different fields and perspectives, measures are taken to try to solve the problem of violence. Institutional communication campaigns against violence and the publication of news related to violent events are often

  1. A novel process for heavy residue hydroconversion using a recoverable pseudo-homogenous catalyst PHC system

    Energy Technology Data Exchange (ETDEWEB)

    Romocki, S.M.; Rhodey, W.G. [Mobis Energy Inc., Calgary, AB (Canada)

    2008-10-15

    This paper described a pseudo-homogenous catalyst (PHC) designed to refine heavy hydrocarbon residues containing sulfur, nitrogen, metals, and asphaltene impurities known to clog pores and deactivate traditional hydrocrackers. The heavy residue hydroconversion (HRH) process incorporated a single particle, chemically generated PHC uniformly distributed in the feed. Thermal decomposition within the reaction system of a water-in-oil emulsion containing ammonium paramolybdate was used to form molybdenum oxide, which was then sulfided within the feed in order to create an ultra-dispersed suspension of catalytically active molybdenum disulfide particles measuring between 2 and 9 nm. A proprietary online catalyst recovery and regeneration step was used to maintain high catalyst activity. The molybdenum was then recovered from a purge stream and then reintroduced to the catalyst preparation area as a catalyst precursor. After being conditioned, the feed was combined with hydrogen and a water-oil catalyst emulsion and introduced into a furnace. Heavy components were cracked, hydrogenated and converted to lighter products. The high performance catalyst system was able to convert 95 per cent of residues at pressures below 7.3 Mpa and at reaction temperatures ranging between 400 and 460 degrees C. The catalyst was tested at a pilot plant using Athabasca vacuum bottoms. It was concluded that the HRH process is now being successfully used to produce 200 barrels of heavy oil per day. Designs for commercial installations are now being prepared. 4 refs., 2 tabs., 2 figs.

  2. Integrated biodiesel production: a comparison of different homogeneous catalysts systems

    Energy Technology Data Exchange (ETDEWEB)

    Vicente, Gemma; Martinez, Mercedes; Aracil, Jose [Complutense Univ., Dept. of Chemical Engineering, Madrid (Spain)

    2004-05-01

    The most common catalysts for biodiesel production are homogeneous basic catalysts. In the present paper, a comparison is made of different basic catalysts (sodium methoxide, potassium methoxide, sodium hydroxide and potassium hydroxide) for methanolysis of sunflower oil. All the reactions were carried out under the same experimental conditions in a batch stirred reactor and the subsequent separation and purification stages in a decanter. The analytical methods included gas chromatography and the determination of fat and oil conventional parameters. The biodiesel purity was near 100 wt. % for all catalysts. However, near 100 wt. % biodiesel yields were only obtained with the methoxide catalysts. According to the material balance of the process, yield losses were due to triglyceride saponification and methyl ester dissolution in glycerol. Obtained biodiesel met the measured specifications, except for the iodine value, according to the German and EU draft standards. Although all the transesterification reactions were quite rapid and the biodiesel layers achieved nearly 100% methyl ester concentrations, the reactions using sodium hydroxide turned out the fastest. (Author)

  3. Economic implication s of the energy conservation potential: scenarios of effects boomerang and backfire incidence in the service sector; Implicacoes economicas do potencial de conservacao de energia: cenarios de incidencia dos efeitos boomerange and backfire no setor de servicos

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Anna Cecilia Jasmim de; Cohen, Claude; Furtado, Luana Moreira de Souza [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Economia]. E-mail: cissajasmim@gmail.com; claude@ppe.ufrj.br; luanamsfurtado@yahoo.com.br

    2006-07-01

    This paper approaches the economic implications of the contra-productivity , from the point of view of energy conservation, put into evidence by the boomerang and backfire effects. The paper used as an example the service sector - specifically the shopping centers. The energy efficiency variation and the possibility of tariff changes will be important factor analysis.

  4. ALMA Observations of the Coldest Place in the Universe: The Boomerang Nebula

    CERN Document Server

    Sahai, R; Huggins, P J; Nyman, L-A; Gonidakis, I

    2013-01-01

    The Boomerang Nebula is the coldest known object in the Universe, and an extreme member of the class of Pre-Planetary Nebulae, objects which represent a short-lived transitional phase between the AGB and Planetary Nebula evolutionary stages. Previous single-dish CO (J=1-0) observations (with a 45 arcsec beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang with ALMA in the CO J=2-1 and J=1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with HST and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter ...

  5. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Gary M. Blythe

    2003-05-01

    This document summarizes progress on Cooperative Agreement DE-FC26-01NT41185, ''Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems,'' during the time period January 1, 2003 through March 31, 2003. The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE), and City Public Service (CPS) of San Antonio are project cofunders. URS Group is the prime contractor. The mercury control process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates with the byproducts from the FGD system. The current project is testing previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, to provide engineering data for future full-scale designs. The pilot-scale tests will continue for up to 14 months at each of two sites to provide longer-term catalyst life data. This is the sixth full reporting period for the subject Cooperative Agreement. During this period, project efforts included continued operation of the pilot unit with three catalysts, conducting catalyst activity measurements, and procuring the fourth catalyst, all for the GRE Coal Creek pilot unit site. Laboratory efforts were also conducted to support catalyst selection for the second pilot unit site, at CPS' Spruce Plant. This technical progress report provides an update on these efforts.

  6. Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

    Energy Technology Data Exchange (ETDEWEB)

    Richard Rhudy

    2006-06-30

    This final report presents and discusses results from a mercury control process development project entitled ''Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems''. The objective of this project was to demonstrate at pilot scale a mercury control technology that uses solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. Oxidized mercury is removed in downstream wet flue gas desulfurization (FGD) absorbers and leaves with the FGD byproducts. The goal of the project was to achieve 90% oxidation of elemental mercury in the flue gas and 90% overall mercury capture with the downstream wet FGD system. The project was co-funded by EPRI and the U.S. Department of Energy's National Energy Technology Laboratory (DOE NETL) under Cooperative Agreement DE-FC26-01NT41185. Great River Energy (GRE) and City Public Service (now CPS Energy) of San Antonio were also project co-funders and provided host sites. URS Group, Inc. was the prime contractor. Longer-term pilot-scale tests were conducted at two sites to provide catalyst life data. GRE provided the first site, at their Coal Creek Station (CCS), which fires North Dakota lignite, and CPS Energy provided the second site, at their Spruce Plant, which fires Powder River Basin (PRB) coal. Mercury oxidation catalyst testing began at CCS in October 2002 and continued through the end of June 2004, representing nearly 21 months of catalyst operation. An important finding was that, even though the mercury oxidation catalyst pilot unit was installed downstream of a high-efficiency ESP, fly ash buildup began to plug flue gas flow through the horizontal catalyst cells. Sonic horns were installed in each catalyst compartment and appeared to limit fly ash buildup. A palladium-based catalyst showed initial elemental mercury oxidation percentages of 95% across the catalyst, declining to 67% after 21 months in service. A carbon

  7. System and method for determining an ammonia generation rate in a three-way catalyst

    Science.gov (United States)

    Sun, Min; Perry, Kevin L; Kim, Chang H

    2014-12-30

    A system according to the principles of the present disclosure includes a rate determination module, a storage level determination module, and an air/fuel ratio control module. The rate determination module determines an ammonia generation rate in a three-way catalyst based on a reaction efficiency and a reactant level. The storage level determination module determines an ammonia storage level in a selective catalytic reduction (SCR) catalyst positioned downstream from the three-way catalyst based on the ammonia generation rate. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the ammonia storage level.

  8. Exhaust system having a gold-platinum group metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Ragle, Christie Susan [Havana, IL; Silver, Ronald G [Peoria, IL; Zemskova, Svetlana Mikhailovna [Edelstein, IL; Eckstein, Colleen J [Metamora, IL

    2011-12-06

    A method of providing an exhaust treatment device is disclosed. The method includes applying a catalyst including gold and a platinum group metal to a particulate filter. The concentration of the gold and the platinum group metal is sufficient to enable oxidation of carbon monoxide and nitric oxide.

  9. Design of Embedded Metal Catalysts via Reverser Micro-Emulsion System: a Way to Suppress Catalyst Deactivation by Metal Sintering

    KAUST Repository

    AlMana, Noor

    2016-06-19

    The development of highly selective and active, long-lasting, robust, low-cost and environmentally benign catalytic materials is the greatest challenge in the area of catalysis study. In this context, core-shell structures where the active sites are embedded inside the protecting shell have attracted a lot of researchers working in the field of catalysis owing to their enhanced physical and chemical properties suppress catalyst deactivation. Also, a new active site generated at the interface between the core and shell may increases the activity and efficiency of the catalyst in catalytic reactions especially for oxide shells that exhibit redox properties such as TiO2 and CeO2. Moreover, coating oxide layer over metal nanoparticles (NPs) can be designed to provide porosity (micropore/mesopore) that gives selectivity of the various reactants by the different gas diffusion rates. In this thesis, we will discuss the concept of catalyst stabilization against metal sintering by a core-shell system. In particular we will study the mechanistic of forming core-shell particles and the key parameters that can influence the properties and morphology of the Pt metal particle core and SiO2 shell (Pt@SiO2) using the reverse micro-emulsion method. The Pt@SiO2 core-shell catalysts were investigated for low-temperature CO oxidation reaction. The study was further extended to other catalytic applications by varying the composition of the core as well as the chemical nature of the shell material. The Pt NPs were embedded within another oxide matrix such as ZrO2 and TiO2 for CO oxidation reaction. These materials were studied in details to identify the factors governing the coating of the oxide around the metal NPs. Next, a more challenging system, namely, bimetallic Ni9Pt NPs embedded in TiO2 and ZrO2 matrix were investigated for dry reforming of methane reaction at high temperatures. The challenges of designing Ni9Pt@oxide core-shell structure with TiO2 and ZrO2 and their tolerance

  10. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Gary M. Blythe

    2003-01-21

    This document summarizes progress on Cooperative Agreement DE-FC26-01NT41185, Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems, during the time period October 1, 2002 through December 31, 2002. The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE), and City Public Service (CPS) of San Antonio are project co-funders. URS Group is the prime contractor. The mercury catalytic oxidation process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates with the byproducts from the FGD system. The co-precipitated mercury does not appear to adversely affect the disposal or reuse properties of the FGD byproduct. The current project testing previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, to provide engineering data for future fullscale designs. The pilot-scale tests will continue for up to 14 months at each of two sites to provide longer-term catalyst life data. This is the fifth full reporting period for the subject Cooperative Agreement. During this period, project efforts included starting up the pilot unit with three catalysts at the first site, conducting catalyst activity measurements, completing comprehensive flue gas sampling and analyses, and procuring additional catalysts for the pilot unit. This technical progress report provides an update on these efforts.

  11. Dehalogenation of Aryl Halides Catalyzed by MontK10 Immobilized PVP-Pd-Sn Catalyst in Aqueous System

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of PVP-Pd-Sn/MontK10 catalysts were prepared by immobilization of PVP[poly(N-vinyl-2-pyrrolidone)] supported bimetallic catalyst using MontK10 as carrier. This catalyst has good catalytic activity for hydrogen transfer dehalogenation of aryl halides. The catalytic reaction was carried out in aqueous system in the presence of phase transfer catalyst and sodium formate as hydrogen source. The catalyst with loading Pd 0.19wt% and molar ratio of Pd/Sn 8:1 gives the highest activity and good stability. This catalyst is more reducible with NaBH4. It is also found that the catalyst is easily separated from the reaction system.

  12. Full-Scale Testing of a Mercury Oxidation Catalyst Upstream of a Wet FGD System

    Energy Technology Data Exchange (ETDEWEB)

    Gary Blythe; Jennifer Paradis

    2010-06-30

    This document presents and discusses results from Cooperative Agreement DE-FC26-06NT42778, 'Full-scale Testing of a Mercury Oxidation Catalyst Upstream of a Wet FGD System,' which was conducted over the time-period July 24, 2006 through June 30, 2010. The objective of the project was to demonstrate at full scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in pulverized-coal-fired flue gas. Oxidized mercury is removed downstream in wet flue gas desulfurization (FGD) absorbers and collected with the byproducts from the FGD system. The project was co-funded by EPRI, the Lower Colorado River Authority (LCRA), who also provided the host site, Great River Energy, Johnson Matthey, Southern Company, Salt River Project (SRP), the Tennessee Valley Authority (TVA), NRG Energy, Ontario Power and Westar. URS Group was the prime contractor and also provided cofunding. The scope of this project included installing and testing a gold-based catalyst upstream of one full-scale wet FGD absorber module (about 200-MW scale) at LCRA's Fayette Power Project (FPP) Unit 3, which fires Powder River Basin coal. Installation of the catalyst involved modifying the ductwork upstream of one of three wet FGD absorbers on Unit 3, Absorber C. The FGD system uses limestone reagent, operates with forced sulfite oxidation, and normally runs with two FGD modules in service and one spare. The full-scale catalyst test was planned for 24 months to provide catalyst life data. Over the test period, data were collected on catalyst pressure drop, elemental mercury oxidation across the catalyst module, and mercury capture by the downstream wet FGD absorber. The demonstration period began on May 6, 2008 with plans for the catalyst to remain in service until May 5, 2010. However, because of continual increases in pressure drop across the catalyst and concerns that further increases would adversely affect Unit 3 operations, LCRA decided to end the

  13. POLYKETONE FROM ETHYLENE WITH CARBON MONOXIDE CATALYZED BY NOVEL CATALYST SYSTEMS BASED ON COPPER WITH BIDENTATE PHOSPHORUS CHELATING LIGANDS

    Institute of Scientific and Technical Information of China (English)

    Jun Huang; Feng-bo Li; Jin Zou; Guo-qing Yuan; Xiu-li Shi; Ding-sheng Yu

    2003-01-01

    Copolymerization of ethylene with carbon monoxide was performed with Cu catalyst systems. Novel catalyst systems based on Cu (Cu(CH3COO)2/ligand/acid) were firstly reported for the copolymerization of ethylene with carbon monoxide, in which the ligand was a bidentate phosphorus chelating ligand. The experimental results showed that this kind of Cu catalyst system exhibited high activity. When DPPP (1,3-bis(diphenylphosphine)propane) and CH3COOH were used catalyst system had the advantages of high stability and low cost.

  14. Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

    Energy Technology Data Exchange (ETDEWEB)

    Richard Rhudy

    2006-06-30

    This final report presents and discusses results from a mercury control process development project entitled ''Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems''. The objective of this project was to demonstrate at pilot scale a mercury control technology that uses solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. Oxidized mercury is removed in downstream wet flue gas desulfurization (FGD) absorbers and leaves with the FGD byproducts. The goal of the project was to achieve 90% oxidation of elemental mercury in the flue gas and 90% overall mercury capture with the downstream wet FGD system. The project was co-funded by EPRI and the U.S. Department of Energy's National Energy Technology Laboratory (DOE NETL) under Cooperative Agreement DE-FC26-01NT41185. Great River Energy (GRE) and City Public Service (now CPS Energy) of San Antonio were also project co-funders and provided host sites. URS Group, Inc. was the prime contractor. Longer-term pilot-scale tests were conducted at two sites to provide catalyst life data. GRE provided the first site, at their Coal Creek Station (CCS), which fires North Dakota lignite, and CPS Energy provided the second site, at their Spruce Plant, which fires Powder River Basin (PRB) coal. Mercury oxidation catalyst testing began at CCS in October 2002 and continued through the end of June 2004, representing nearly 21 months of catalyst operation. An important finding was that, even though the mercury oxidation catalyst pilot unit was installed downstream of a high-efficiency ESP, fly ash buildup began to plug flue gas flow through the horizontal catalyst cells. Sonic horns were installed in each catalyst compartment and appeared to limit fly ash buildup. A palladium-based catalyst showed initial elemental mercury oxidation percentages of 95% across the catalyst, declining to 67% after 21 months in service. A carbon

  15. ALMA OBSERVATIONS OF THE COLDEST PLACE IN THE UNIVERSE: THE BOOMERANG NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, R. [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States); Vlemmings, W. H. T. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden); Huggins, P. J. [Physics Department, New York University, 4 Washington Place, New York, NY 10003 (United States); Nyman, L.-Å. [Joint ALMA Observatory (JAO), Alonso de Cordova 3107, Vitacura, Santiago de Chile (Chile); Gonidakis, I., E-mail: raghvendra.sahai@jpl.nasa.gov [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Marsfield NSW 2122 (Australia)

    2013-11-10

    The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45'' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist—these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating.

  16. ALMA Observations of the Coldest Place in the Universe: The Boomerang Nebula

    Science.gov (United States)

    Sahai, R.; Vlemmings, W. H. T.; Huggins, P. J.; Nyman, L.-Å.; Gonidakis, I.

    2013-11-01

    The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45'' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist—these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating.

  17. Heteroepitaxial praseodymium sesquioxide films on Si(1 1 1): A new model catalyst system for praseodymium oxide based catalysts

    Science.gov (United States)

    Schaefer, A.; Schroeder, T.; Lupina, G.; Borchert, Y.; Dabrowski, J.; Wenger, Ch.; Bäumer, M.

    2007-03-01

    The structure, growth and stoichiometry of heteroepitaxial Pr 2O 3 films on Si(1 1 1) were characterized by a combined RHEED, XRD, XPS and UPS study in view of future applications as a surface science model catalyst system. RHEED and XRD confirm the growth of a (0 0 0 1) oriented hexagonal Pr 2O 3 phase on Si(1 1 1), matching the surface symmetry by aligning the oxide in-plane direction along the Si azimuth. After an initial nucleation stage RHEED growth oscillation studies point to a Frank-van der Merwe growth mode up to a thickness of approximately 12 nm. XPS and UPS prove that the initial growth of the Pr 2O 3 layer on Si up to ˜1 nm thickness is characterized by an interface reaction with Si. Nevertheless stoichiometric Pr 2O 3 films of high crystalline quality form on top of these Pr-silicate containing interlayers.

  18. Catalyst system and process for benzyl ether fragmentation and coal liquefaction

    Science.gov (United States)

    Zoeller, Joseph Robert

    1998-04-28

    Dibenzyl ether can be readily cleaved to form primarily benzaldehyde and toluene as products, along with minor amounts of bibenzyl and benzyl benzoate, in the presence of a catalyst system comprising a Group 6 metal, preferably molybdenum, a salt, and an organic halide. Although useful synthetically for the cleavage of benzyl ethers, this cleavage also represents a key model reaction for the liquefaction of coal; thus this catalyst system and process should be useful in coal liquefaction with the advantage of operating at significantly lower temperatures and pressures.

  19. Probing primordial non Gaussianity in the BOOMERanG CMB maps: an analysis based on analytical Minkowski functionals

    Energy Technology Data Exchange (ETDEWEB)

    Migliaccio, M.; Natoli, P.; De Troia, G. [Dipartimento di Fisica, Universita di Roma ' Tor Vergata' , Via della Ricerca Scientifica, 1 I-00133 Roma (Italy); Hikage, C. [School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA (United Kingdom); Komatsu, E. [Texas Cosmology Center, University of Texas at Austin, 1 University Station, C1400, Austin, TX 78712 (United States); Ade, P.A.R. [School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA (United Kingdom); Bock, J.J. [Jet Propulsion Laboratory, Pasadena, CA (United States); Bond, J.R. [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, Ontario (Canada); Borrill, J. [Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Boscaleri, A. [IFAC-CNR, Firenze (Italy); Contaldi, C.R. [Theoretical Physics Group, Imperial College, London (United Kingdom); Crill, B.P. [Jet Propulsion Laboratory, Pasadena, CA (United States); Bernardis, P. de [Dipartimento di Fisica, Universita La Sapienza, Roma (Italy); Gasperis, G. de [Dipartimento di Fisica, Universita di Roma ' Tor Vergata' , Via della Ricerca Scientifica, 1 I-00133 Roma (Italy); Oliveira-Costa, A. de [Department of Physics, MIT, Cambridge, MA 02139 (United States); Di Stefano, G. [Istituto Nazionale di Geofisica e Vulcanologia, 00143 Rome (Italy); Hivon, E. [Institut d' Astrophysique, Paris (France); Kisner, T.S. [Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Jones, W.C. [Department of Physics, Princeton University, Princeton, NJ 0854 (United States); Lange, A.E. [Observational Cosmology, California Institute of Technology, Pasadena, CA (United States)

    2009-10-15

    Minkowski functionals are a powerful tool to constrain the Gaussianity of the Cosmic Microwave Background (CMB). In the limit of a weakly non Gaussian field, a perturbative approach can be derived [Hikage C., Komatsu E., and Matsubara T., 2006, ApJ, 653, 11] that is completely based on analytical formulae without requiring computationally intensive, dedicated Monte Carlo non Gaussian simulations of the CMB anisotropy. We apply this machinery to an intensity map derived from the 1998 and 2003 flights of BOOMERanG, analyzed here together for the first time. We set limits on the non-linear coupling parameter f{sub NL} as -1020BOOMERanG 2003 dataset. These limits are the most stringent ever set among suborbital experiments.

  20. Highly practical copper(I)/TEMPO catalyst system for chemoselective aerobic oxidation of primary alcohols.

    Science.gov (United States)

    Hoover, Jessica M; Stahl, Shannon S

    2011-10-26

    Aerobic oxidation reactions have been the focus of considerable attention, but their use in mainstream organic chemistry has been constrained by limitations in their synthetic scope and by practical factors, such as the use of pure O(2) as the oxidant or complex catalyst synthesis. Here, we report a new (bpy)Cu(I)/TEMPO catalyst system that enables efficient and selective aerobic oxidation of a broad range of primary alcohols, including allylic, benzylic, and aliphatic derivatives, to the corresponding aldehydes using readily available reagents, at room temperature with ambient air as the oxidant. The catalyst system is compatible with a wide range of functional groups and the high selectivity for 1° alcohols enables selective oxidation of diols that lack protecting groups.

  1. NO.sub.x catalyst and method of suppressing sulfate formation in an exhaust purification system

    Science.gov (United States)

    Balmer-Millar, Mari Lou; Park, Paul W.; Panov, Alexander G.

    2007-06-26

    The activity and durability of a zeolite lean-burn NOx catalyst can be increased by loading metal cations on the outer surface of the zeolite. However, the metal loadings can also oxidize sulfur dioxide to cause sulfate formation in the exhaust. The present invention is a method of suppressing sulfate formation in an exhaust purification system including a NO.sub.x catalyst. The NO.sub.x catalyst includes a zeolite loaded with at least one metal. The metal is selected from among an alkali metal, an alkaline earth metal, a lanthanide metal, a noble metal, and a transition metal. In order to suppress sulfate formation, at least a portion of the loaded metal is complexed with at least one of sulfate, phosphate, and carbonate.

  2. Chemical Fixation of CO2 with Highly Efficient ZnCl/[BMIm]Br Catalyst System

    Institute of Scientific and Technical Information of China (English)

    Li Fuwei; Xia Chungu

    2004-01-01

    The search for environmentally benign and economic process has been the impetus for much of the research involving epoxide and carbon dioxide coupling in view of the so called "green chemistry" and" atom economy ", since CO2 is a renewable resource and can be used as a safe and cheap C 1 building block to synthesize useful organic compounds without producing any coproducts.[1-2] One of the most attractive synthetic goals starting from carbon dioxide is the chemical fixation of CO2 onto epoxide to afford the five-membered cyclic carbonates (Scheme 1),which are excellent aprotic polar solvents and are used extensively as intermediates in the production of pharmaceuticals and fine chemicals.[3] In the last decades of the twentieth century numerous catalytic systems have been developed for this transformation. While some advances have been obtained, all suffer from either low catalyst stability/reactivity, the need for co-solvent, or the requirement for high pressure and/or catalyst costing expensive.[4] Therefore, to find an effective,not exrensive, environmentally benign and economic catalyst system is urgent.In this paper, chemical fixation of CO2 with mono-substituted terminal epoxides or cyclohexene oxide to form cyclic carbonates under the ZnCl2/[BMIm]Br Catalyst System without using additional organic solvents was achieved in excellent selectivity (>98%) and TOF(5410h-1) Besides,the pure cis-cyclic carbonate of cyclohexene oxide was obtained in this catalyst system.It was important to note that the catalyst could be recovered by simple vacuum distillation of the corresponding cyclic carbonates and could be used six times almost without losing its catalytic activity and selectivity. The catalyst system was found to be applicable to a variety of terminal epoxides and cyclohexene oxide, forming the corresponding cyclic carbonates in very high TOF and more than 98% selectivity. Based on the obtained results, we also propose the plausible mechanism for this

  3. An innovative catalyst system for slurry-phase Fischer-Tropsch synthesis: Cobalt plus a water-gas-shift catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Satterfield, C.N.; Yates, I.C.; Chanenchuk, C.

    1991-07-01

    The feasibility of using a mechanical mixture of a Co/MgO/SiO{sub 2} Fischer-Tropsch catalyst and a Cu-ZnO/Al{sub 2}O{sub 3} water-gas-shift (WGS) catalyst for hydrocarbon synthesis in a slurry reactor has been established. Such a mixture can combine the superior product distribution from cobalt with the high activity for the WGS reaction characteristic of iron. Weight ratios of Co/MgO/SiO{sub 2} to Cu-ZnO/Al{sub 2}O{sub 3} of 0.27 and 0.51 for the two catalysts were studied at 240{degrees}C, 0.79 MPa, and in situ H{sub 2}/CO ratios between 0.8 and 3.0. Each catalyst mixture showed stable Fischer-Tropsch activity for about 400 hours-on-stream at a level comparable to the cobalt catalyst operating alone. The Cu-ZnO/Al{sub 2}O{sub 3} catalyst exhibited a very slow loss of activity under these conditions, but when operated alone it was stable in a slurry reactor at 200--220{degrees}C, 0.79--1.48 MPa, and H{sub 2}/CO in situ ratios between 1.0 and 2.0. The presence of the water-gas-shift catalyst did not affect the long-term stability of the primary Fischer-Tropsch selectivity, but did increase the extent of secondary reactions, such as l-alkene hydrogenation and isomerization.

  4. Method of preparing and utilizing a catalyst system for an oxidation process on a gaseous hydrocarbon stream

    Science.gov (United States)

    Berry, David A; Shekhawat, Dushyant; Smith, Mark; Haynes, Daniel

    2013-07-16

    The disclosure relates to a method of utilizing a catalyst system for an oxidation process on a gaseous hydrocarbon stream with a mitigation of carbon accumulation. The system is comprised of a catalytically active phase deposited onto an oxygen conducting phase, with or without supplemental support. The catalytically active phase has a specified crystal structure where at least one catalytically active metal is a cation within the crystal structure and coordinated with oxygen atoms within the crystal structure. The catalyst system employs an optimum coverage ratio for a given set of oxidation conditions, based on a specified hydrocarbon conversion and a carbon deposition limit. Specific embodiments of the catalyst system are disclosed.

  5. [Boomerang flap. A true single-stage pedicled cross finger flap].

    Science.gov (United States)

    Legaillard, P; Grangier, Y; Casoli, V; Martin, D; Baudet, J

    1996-06-01

    The indications for cover of long fingers have been considerably modified over recent years as a result of the concept of retrograde flow flaps. However, in some cases in which the dorsal digital networks cannot be used, cross-finger flaps are still indicated for cover of long fingers beyond the PIP joint. The authors present a new flap eliminating the need for this rather complicated procedure. The donor site takes advantage of the rich dorsal collateral arterial network of P1 of an adjacent healthy finger. The flap can be raised due to the constant existence of a bifurcation between the collateral dorsal digital arterial networks and the anastomoses situated at various levels between the dorsal and palmar collateral networks of the long fingers, which are constant as far as the PIP joint. A dorsolateral flap can therefore be raised from a healthy finger and transferred to the injured finger by raising the fatty connective tissue, including the dorsal collateral pedicles, in the shape of a boomerang. This flap covers distal defects from the PIP joint to the fingertip. The authors describe the anatomical basis for raising of the flap, the operative technique and report six clinical cases with a mean follow-up of 11 months.

  6. A dangerous boomerang: Injunctive norms, hostile sexist attitudes, and male-to-female sexual aggression.

    Science.gov (United States)

    Bosson, Jennifer K; Parrott, Dominic J; Swan, Suzanne C; Kuchynka, Sophie L; Schramm, Andrew T

    2015-01-01

    This study examined the interactive effects of injunctive norm exposure and hostile and benevolent sexist attitudes on men's sexually aggressive responses during a behavioral analogue paradigm in which they interacted online with a bogus female partner. Heterosexual adult men (n = 201), recruited from an online sample, read fictional information regarding other men's approval of misogynistic, paternalistic, or egalitarian treatment of women, or non-gender-relevant control information. Through a media preference survey, men then learned that their female partner disliked sexual content in films, after which they had an opportunity to send her up to 120 sec' worth of either a sexually explicit or nonsexual film clip. Validating the online sexual aggression paradigm, men with a 1-year history of sexual assault exhibited more sexually aggressive responding during the film selection paradigm. Moreover, exposure to injunctive norm information produced a boomerang effect, such that men high in hostile sexist attitudes showed an increase in sexual aggression when confronted with paternalism and gender equality norms. Conversely, exposure to paternalism and gender equality norms suppressed the otherwise protective function of high benevolent sexism in reducing men's sexually aggressive tendencies. The implications of these results for social norms interventions are discussed.

  7. An analytical model for the evolution of the coldest component of the Boomerang Nebula

    Science.gov (United States)

    Bohigas, J.

    2017-04-01

    The most striking feature of the Boomerang Nebula is a large nearly spherical cloud where the temperature is close to 2 K. At its inner and outer boundaries, this cloud is expanding at velocities close to 35 and 180 km s-1. The cloud surrounds an asymptotic giant branch (AGB) star and a smaller bipolar molecular cloud, expanding much more slowly. The ultracold spherical cloud has been and still is expanding into a rarefied medium, since there is no trace of a shock wave. This ultracold cloud is modelled using the analytical solution for a power-driven expansion of a spherically symmetric cloud, followed by an adiabatic expansion phase, both into a vacuum. Assuming that the cloud is at a distance of 1500 pc, the present temperature and velocity profile are reproduced with a model where the cloud has an energy close to 8.5 × 1046 erg per solar mass and was ejected 1000 yr ago. In this model, the power-driven phase lasts for ∼10 yr and half of the energy is injected in less than a year. The general features of this model, are amenable with what is found in other spherical shells surrounding AGB stars, the small amount of mass lost by massive OH/IR stars and evolutionary models indicating that there may be extremely high and abrupt mass-loss phases in AGB stars. The energy and time-scale suggest that the ejection of the cold spherical cloud was an intermediate luminosity transient.

  8. High-throughput reactor system with individual temperature control for the investigation of monolith catalysts.

    Science.gov (United States)

    Dellamorte, Joseph C; Vijay, Rohit; Snively, Christopher M; Barteau, Mark A; Lauterbach, Jochen

    2007-07-01

    A high-throughput parallel reactor system has been designed and constructed to improve the reliability of results from large diameter catalysts such as monoliths. The system, which is expandable, consists of eight quartz reactors, 23.5 mm in diameter. The eight reactors were designed with separate K type thermocouples and radiant heaters, allowing for the independent measurement and control of each reactor temperature. This design gives steady state temperature distributions over the eight reactors within 0.5 degrees C of a common setpoint from 50 to 700 degrees C. Analysis of the effluent from these reactors is performed using rapid-scan Fourier transform infrared (FTIR) spectroscopic imaging. The integration of this technique to the reactor system allows a chemically specific, truly parallel analysis of the reactor effluents with a time resolution of approximately 8 s. The capabilities of this system were demonstrated via investigation of catalyst preparation conditions on the direct epoxidation of ethylene, i.e., on the ethylene conversion and the ethylene oxide selectivity. The ethylene, ethylene oxide, and carbon dioxide concentrations were calibrated based on spectra from FTIR imaging using univariate and multivariate chemometric techniques. The results from this analysis showed that the calcination conditions significantly affect the ethylene conversion, with a threefold increase in the conversion when the catalyst was calcined for 3 h versus 12 h at 400 degrees C.

  9. Polyethylene glycol: A recyclable solvent system for the synthesis of benzimidazole derivatives using CAN as catalyst

    Indian Academy of Sciences (India)

    Mazaahir Kidwai; Anwar Jahan; Divya Bhatnagar

    2010-07-01

    Ceric ammonium nitrate (CAN) efficiently catalysed the synthesis of benzimidazole derivatives from -phenylenediamine and aldehydes in PEG. This method provides a novel route for the synthesis of benzimidazoles in good yields with little catalyst loading. The recovery and the successful reutilization of the solvent system are also presented. Moreover, the easy set-up and purification tasks of this sustainable method make it appealing for bulk industry applications.

  10. Dehydration of xylose to furfural over niobium phosphate catalyst in biphasic solvent system

    Institute of Scientific and Technical Information of China (English)

    Boonrat; Pholjaroen; Ning; Li; Zhiqiang; Wang; Aiqin; Wang; Tao; Zhang

    2013-01-01

    Phosphoric acid treated niobic acid(NbP)was used for the dehydration of xylose to furfural in biphasic solvent system,which was found to exhibit the best performance among the tested catalysts.The excellent performance of NbP could be explained by the better synergistic cooperation between Bro¨nsted and Lewis acid sites.Moreover,NbP showed good stability and no obvious deactivation or leaching of Nb could be observed after six continuous recycles.

  11. A Systematic Modelling Framework for Phase Transfer Catalyst Systems

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata; Sales-Cruz, Mauricio; Hyung Kim, Sun

    2016-01-01

    in an aqueous phase. These reacting systems are receiving increased attention as novel organic synthesis options due to their flexible operation, higher product yields, and ability to avoid hazardous or expensive solvents. Major considerations in the design and analysis of PTC systems are physical and chemical...... equilibria, as well as kinetic mechanisms and rates. This paper presents a modelling framework for design and analysis of PTC systems that requires a minimum amount of experimental data to develop and employ the necessary thermodynamic and reaction models and embeds them into a reactor model for simulation....... The application of the framework is made to two cases in order to highlight the performance and issues of activity coefficient models for predicting design and operation and the effects when different organic solvents are employed....

  12. A new grafting technique for tympanoplasty: tympanoplasty with a boomerang-shaped chondroperichondrial graft (TwBSCPG).

    Science.gov (United States)

    Dündar, Rıza; Soy, Fatih Kemal; Kulduk, Erkan; Muluk, Nuray Bayar; Cingi, Cemal

    2014-10-01

    The aim of this study was to introduce a new grafting technique in tympanoplasty that involves use of a boomerang-shaped chondroperichondrial graft (BSCPG). The anatomical and functional results were evaluated. A new tympanoplasty with boomerang-shaped chondroperichondrial graft (TwBSCPG) technique was used in 99 chronic otitis media patients with central or marginal perforation of the tympanic membrane and a normal middle ear mucosa. All 99 patients received chondroperichondrial cartilage grafts with a boomerang-shaped cartilage island left at the anterior and inferior parts. Postoperative follow-ups were conducted at months 1, 6, and 12. Preoperative and postoperative audiological examinations were performed and air-bone gaps were calculated according to the pure-tone averages (PTAs) of the patients. In the preoperative period, most (83.8%) air-bone gaps were ≥ 16 dB; after operating using the TwBSCPG technique, the air-bone gaps decreased to 0-10 dB in most patients (77.8%). In the TwBSCPG patients, the mean preoperative air-bone gap was 22.02 ± 6.74 dB SPL. Postoperatively, the mean postoperative air-bone gap was 8.70 ± 5.74 dB SPL. The TwBSCPG technique therefore decreased the postoperative air-bone gap compared to that preoperatively (p = 0.000, z = -8.645). At the 1-month follow-up, there were six graft perforations and one graft retraction. At the 6-month follow-up, there were nine graft perforations and three graft retractions. At 12 months, there were seven graft perforations and four graft retractions. During the first year after the boomerang tympanoplasty surgery, graft lateralization was not detected in any patient. Retractions were grade 1 according to the Sade classification and were localized to the postero-superior quadrant of the tympanic membrane. The TwBSCPG technique has benefits with respect to postoperative anatomical and audiological results. It prevents perforation of the tympanic membrane at the anterior quadrant and avoids graft

  13. Application of New Electrolyte Model to Phase Transfer Catalyst (PTC) Systems

    DEFF Research Database (Denmark)

    2015-01-01

    Abstract Phase transfer catalyst (PTC) is used to transfer the desirable active form of an anion from the aqueous phase to organic phase where the reaction occurs. One of major challenges for process design of the PTC system is to establish a reliable thermodynamic model capable of describing phase...... in PTC systems, thereby, extending the application range of the PTC-system model. The solubility of PTC in organic solvents, which is a key factor for strategy of PTC and solvent selection, has been calculated using the e-NRTL-SAC model....

  14. System Identification for Experimental Study for Polymerization Catalyst Reaction in Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Ahmmed Saadi Ibrehem

    2011-11-01

    Full Text Available In this work, system identification method is used to capture the reactor characteristics of production rate of polyethylene (PE based on published experimental data. The identification method is used to measure the percentage effect on the production rate of PE by measuring the effect of input factors of temperature of reaction, hydrogen concentration, and [Al]/[Ti] molar catalyst ratio. Temperature of reaction has big effects equal 52.4 % on the output of the system and 47.6 % on interaction of the system's parameters compare to other two factors. Also, hydrogen concentration has big effect equal 45.66 % on the output of the system and 14.7 % on interaction of the system's parameters. [Al]/[Ti] molar catalyst ratio has big effect on interaction of the system equal 28.6 and 1.94 % on the output of the system but less than the reaction temperature and hydrogen concentration. All these results depend on experiment results and these results are very important in industrial plants. ©2011 BCREC UNDIP. All rights reserved(Received: 13rd May 2011; Revised: 27th July 2011; Accepted: 22th September 2011[How to Cite: Ahmmed S. Ibrehem. (2011. System Identification for Experimental Study for Polymerization Catalyst Reaction in Fluidized Bed. Bulletin of Chemical Reaction Engineering & Catalysis, 6 (2: 137-146. doi:10.9767/bcrec.6.2.874.137-146][How to Link / DOI: http://dx,doi.org/10.9767/bcrec.6.2.874.137-146 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/874 ] | View in 

  15. System and method for controlling an engine based on ammonia storage in multiple selective catalytic reduction catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Sun, MIn; Perry, Kevin L.

    2015-11-20

    A system according to the principles of the present disclosure includes a storage estimation module and an air/fuel ratio control module. The storage estimation module estimates a first amount of ammonia stored in a first selective catalytic reduction (SCR) catalyst and estimates a second amount of ammonia stored in a second SCR catalyst. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the first amount, the second amount, and a temperature of a substrate disposed in the second SCR catalyst.

  16. Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gary Blythe; Conor Braman; Katherine Dombrowski; Tom Machalek

    2010-12-31

    This document is the final technical report for Cooperative Agreement DE-FC26-04NT41992, 'Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems,' which was conducted over the time-period January 1, 2004 through December 31, 2010. The objective of this project has been to demonstrate at pilot scale the use of solid catalysts and/or fixed-structure mercury sorbents to promote the removal of total mercury and oxidation of elemental mercury in flue gas from coal combustion, followed by wet flue gas desulfurization (FGD) to remove the oxidized mercury at high efficiency. The project was co-funded by the U.S. DOE National Energy Technology Laboratory (DOE-NETL), EPRI, Great River Energy (GRE), TXU Energy (now called Luminant), Southern Company, Salt River Project (SRP) and Duke Energy. URS Group was the prime contractor. The mercury control process under development uses fixed-structure sorbents and/or catalysts to promote the removal of total mercury and/or oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone FGD systems. Oxidized mercury not adsorbed is removed in the wet FGD absorbers and leaves with the byproducts from the FGD system. The project has tested candidate materials at pilot scale and in a commercial form, to provide engineering data for future full-scale designs. Pilot-scale catalytic oxidation tests have been completed for periods of approximately 14 to19 months at three sites, with an additional round of pilot-scale fixed-structure sorbent tests being conducted at one of those sites. Additionally, pilot-scale wet FGD tests have been conducted downstream of mercury oxidation catalysts at a total of four sites. The sites include the two of three sites from this project and two sites where catalytic oxidation pilot testing was conducted as part of a previous DOE-NETL project. Pilot-scale wet FGD tests were also conducted at a fifth site, but with no catalyst or fixed

  17. Design of heterogeneous catalysts

    DEFF Research Database (Denmark)

    Frey, Anne Mette

    was inspired by a computational screening, suggesting that alloys such as Ni-Fe, Co-Ni, and Co-Fe should show superior activity to the industrially used nickel catalyst. Especially the Ni-Fe system was considered to be interesting, since such alloy catalysts should be both more active and cheaper than the Ni...... well, and the best catalyst prepared had a C5+ yield almost a factor of two higher than a standard air calcined Co catalyst. In the NH3-SCR reaction it is desirable to develop an active and stable catalyst for NOx removal in automotive applications, since the traditionally used vanadium-based catalyst...... pose an environmental risk. The focus was put on iron-containing zeolite catalysts, since these recently have shown great potential as catalysts for the process. A number of different zeolites were compared. BEA was found to be the most active, thus focus was put on this material. Different preparation...

  18. The Boomerang-Chapare transfer zone (recent oil discovery trend in Bolivia): structural interpretation and experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Specht, M.; Colletta, B.; Letouzey, J. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France); Baby, P. [Office de la Recherche Scientifique et Technique d`Outre-Mer (ORSTOM), 93 - Bondy (France); Oller, J.; Montemurro, G. [Yacimientos Petroliferos Fiscales Bolivianos, La Paz (Bolivia)

    1996-12-01

    The central part of the Bolivian Andean fold and thrust belt is characterized by the existence of lateral and oblique ramps offsetting its from. The Boomerang-Chapare transfer zone, north of Santa Cruz, is the most dramatic in so far as it provokes a hundred-kilometer sinistral offset of the Andean thrust front. Combined surface and subsurface data have been used here to present an up-to-date structural and kinematic model of the Boomerang-Chapare transfer zone. Moreover, a set of analog modeling in a sandbox has enabled us to test our hypotheses and study the propagation of the thrusts. THE 3D visualization of the deformed model was done by computerized X-ray tomography. We thus show that the main decollement level is located at the bottom of a Paleozoic sedimentary wedge lying on the Brazilian shield and that geometry of the border of the detached wedge is what governs and situates the development of the transfer zone. The relation between thrust propagation sequence and location of oil fields is then examined. (authors). 18 refs., 13 figs., 7 photos.

  19. An Economical, Highly Efficient and Recyclable Catalyst System for Asymmetric Dihydroxylation of Olefins

    Institute of Scientific and Technical Information of China (English)

    金瑛; 孙晓莉; 姜茹; 张生勇

    2005-01-01

    A reusable cinchona alkaloid derivative ligand, which could be easily synthesized by two step transformation with cheap 3,6-dichloropyridazine and quinine as materials, was applied to homogeneous asymmetric dihydroxylation of olefins with NMO as co-oxidant in Me2CO-H20 system and the products could be extracted with Et2O from the recyclable catalyst system. 80%---93% yield and 51%-99% ee have been obtained. When trans-stilbene was chosen as the substrate for recycling experiment, 88%-92% yield and >99% ee have been obtained for ten recycles.

  20. Photocatalytic oxidation of organic compounds in a hybrid system composed of a molecular catalyst and visible light-absorbing semiconductor.

    Science.gov (United States)

    Zhou, Xu; Li, Fei; Li, Xiaona; Li, Hua; Wang, Yong; Sun, Licheng

    2015-01-14

    Photocatalytic oxidation of organic compounds proceeded efficiently in a hybrid system with ruthenium aqua complexes as catalysts, BiVO4 as a light absorber, [Co(NH3)5Cl](2+) as a sacrificial electron acceptor and water as an oxygen source. The photogenerated holes in the semiconductor are used to oxidize molecular catalysts into the high-valent Ru(IV)=O intermediates for 2e(-) oxidation.

  1. Thermal desorption study of catalytic systems. Communication 20. Adsorption of water vapors on the calcium aluminate components of catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, V.D.; Danyushevskii, V.Y.; Golosman, E.Z.; Rubinstein, A.M.; Yakerson, V.I.

    1985-05-01

    Ca aluminates are used as a component of catalysts of gas-phase processes, some of which take place with the participation of water. Nickel calcium aluminate catalysts are thus used for hydrogenation of CO and CO/sub 2/ to CH/sub 4/ and water; zinc calcium aluminate catalysts are used for sulfur purification of process gases, where water is liberated during sulfiding of ZnO; and copper zinc calcium aluminate catalysts are used in low-temperature conversion of CO with water vapor. It is also known that Ca aluminates undergo various transformations in aqueous media with the formation of Ca hydroaluminates. This paper discusses the adsorption of water from the gas phase on calcium aluminate systems, which was investigated by the thermal desorption method. Samples of varying phase composition, different CaO/Al/sub 2/O/sub 3/ ratios, and specific surface areas were also studied and are reported on here.

  2. Catalyst development and systems analysis of methanol partial oxidation for the fuel processor - fuel cell integration

    Energy Technology Data Exchange (ETDEWEB)

    Newson, E.; Mizsey, P.; Hottinger, P.; Truong, T.B.; Roth, F. von; Schucan, Th.H. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Methanol partial oxidation (pox) to produce hydrogen for mobile fuel cell applications has proved initially more successful than hydrocarbon pox. Recent results of catalyst screening and kinetic studies with methanol show that hydrogen production rates have reached 7000 litres/hour/(litre reactor volume) for the dry pox route and 12,000 litres/hour/(litre reactor volume) for wet pox. These rates are equivalent to 21 and 35 kW{sub th}/(litre reactor volume) respectively. The reaction engineering problems remain to be solved for dry pox due to the significant exotherm of the reaction (hot spots of 100-200{sup o}C), but wet pox is essentially isothermal in operation. Analyses of the integrated fuel processor - fuel cell systems show that two routes are available to satisfy the sensitivity of the fuel cell catalysts to carbon monoxide, i.e. a preferential oxidation reactor or a membrane separator. Targets for individual system components are evaluated for the base and best case systems for both routes to reach the combined 40% efficiency required for the integrated fuel processor - fuel cell system. (author) 2 figs., 1 tab., 3 refs.

  3. Predictive Modelling of Phase-Transfer Catalyst Systems for Improved and Innovative Design

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata; Hyung Kim, Sun; Sales-Cruz, Mauricio

    2016-01-01

    increasing attention as a novel organic synthesis option due to its flexible and easier operation, higher production yield, and ability to eliminate expensive solvents, although, not eliminating the use of solvents. New mathematical models of the PTC system, which includes physical and chemical equilibrium......Phase-transfer catalyst (PTC) systems contain two immiscible liquid phases with a heterogeneous PTC transferring active ion from one phase to the other for converting the reactant to the desired product, and in the process generating the inactive ion. This type of reacting systems is receiving......, reaction mechanism and unit operation has been developed. In the developed model, the PTC system is divided into four sub-systems of aqueous-organic solvent partition, inorganic salt in aqueous phase, PTC in aqueous phase, and PTC in aqueous phase. Each subsystem requires an appropriate thermodynamic model...

  4. Nanolithographic Fabrication and Heterogeneous Reaction Studies ofTwo-Dimensional Platinum Model Catalyst Systems

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, Anthony Marshall [Univ. of California, Berkeley, CA (United States)

    2006-05-20

    In order to better understand the fundamental components that govern catalytic activity, two-dimensional model platinum nanocatalyst arrays have been designed and fabricated. These catalysts arrays are meant to model the interplay of the metal and support important to industrial heterogeneous catalytic reactions. Photolithography and sub-lithographic techniques such as electron beam lithography, size reduction lithography and nanoimprint lithography have been employed to create these platinum nanoarrays. Both in-situ and ex-situ surface science techniques and catalytic reaction measurements were used to correlate the structural parameters of the system to catalytic activity.

  5. In situ adsorption-catalysis system for the removal of o-xylene over an activated carbon supported Pd catalyst

    Institute of Scientific and Technical Information of China (English)

    HUANG Shaoyong; ZHANG Changbin; HE Hong

    2009-01-01

    An activated carbon (AC) supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene. In this study, three kinds of Pd/AC catalysts were prepared and tested to investigate the synergistic efficiency between adsorption and catalysis for o-xylene removal. The Pd/AC catalyst was first used as an adsorbent to concentrate dilute o-xylene at low temperature. After saturated adsorption, the adsorbed o-xylene was oxidized to CO2 and H2O by raising the temperature of the catalyst bed. The results showed that more than 99% of the adsorbed o-xylene was completely oxidized to CO2 over a 5% Pd/AC catalyst at 140℃. Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), temperature-programmed desorption (TPD), and temperature-programmed oxidation (TPO) were applied to investigate the physical properties of o-xylene adsorption-desorption and the in situ adsorption-catalysis activity of the AC support and Pd/AC catalyst. A synergistic relationship between the AC support and the active Pd species for the removal of low concentrations of o-xylene was established.

  6. Efficient solar-to-fuels production from a hybrid microbial-water-splitting catalyst system.

    Science.gov (United States)

    Torella, Joseph P; Gagliardi, Christopher J; Chen, Janice S; Bediako, D Kwabena; Colón, Brendan; Way, Jeffery C; Silver, Pamela A; Nocera, Daniel G

    2015-02-24

    Photovoltaic cells have considerable potential to satisfy future renewable-energy needs, but efficient and scalable methods of storing the intermittent electricity they produce are required for the large-scale implementation of solar energy. Current solar-to-fuels storage cycles based on water splitting produce hydrogen and oxygen, which are attractive fuels in principle but confront practical limitations from the current energy infrastructure that is based on liquid fuels. In this work, we report the development of a scalable, integrated bioelectrochemical system in which the bacterium Ralstonia eutropha is used to efficiently convert CO2, along with H2 and O2 produced from water splitting, into biomass and fusel alcohols. Water-splitting catalysis was performed using catalysts that are made of earth-abundant metals and enable low overpotential water splitting. In this integrated setup, equivalent solar-to-biomass yields of up to 3.2% of the thermodynamic maximum exceed that of most terrestrial plants. Moreover, engineering of R. eutropha enabled production of the fusel alcohol isopropanol at up to 216 mg/L, the highest bioelectrochemical fuel yield yet reported by >300%. This work demonstrates that catalysts of biotic and abiotic origin can be interfaced to achieve challenging chemical energy-to-fuels transformations.

  7. Exploration of Cocatalyst Effects on a Bimetallic Cobalt Catalyst System: Enhanced Activity and Enantioselectivity in Epoxide Polymerization

    KAUST Repository

    Widger, Peter C. B.

    2011-07-26

    Organic ionic compounds were synthesized and investigated as cocatalysts with a bimetallic cobalt complex for enantioselective epoxide polymerization. The identities of both the cation and the anion were systematically varied, and the subsequent reactivity was studied. The nature of the ionic cocatalyst dramatically impacted the rate and enantioselectivity of the catalyst system. The ionic cocatalyst [P(N=P(N(CH2)4)3) 4 +][tBuCO2 -] in combination with a bimetallic cobalt complex produced a catalyst system that exhibited the greatest activity and selectivity for a variety of monosubstituted epoxides. © 2011 American Chemical Society.

  8. Incorporation of Water-Oxidation Catalysts into Photoinduced Electron Transfer Systems: Toward Solar Fuel Generation via Artificial Photosynthesis

    Science.gov (United States)

    Vagnini, Michael Thomas

    mechanisms and probing highly-reactive intermediates, and it also establishes a basis in systems design for photodriving catalytic processes. Covalent dye-catalyst assemblies have been gaining recognition as a useful motif for incorporation into dye-sensitized photoanodes for photoelectrochemical water-splitting cells, and the PMI-Ir catalyst unit is well-poised, both in the energetics and kinetics of its electron transfer properties, to improve upon current solar-driven fuel-forming devices.

  9. Clean Catalysts for Water Recovery Systems in Long-Duration Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Oxidation catalysts based on innovative, physically-robust activated carbon materials containing dispersed noble metals are essential in process optimization for...

  10. Practical aerobic oxidations of alcohols and amines with homogeneous copper/TEMPO and related catalyst systems.

    Science.gov (United States)

    Ryland, Bradford L; Stahl, Shannon S

    2014-08-18

    Oxidations of alcohols and amines are common reactions in the synthesis of organic molecules in the laboratory and industry. Aerobic oxidation methods have long been sought for these transformations, but few practical methods exist that offer advantages over traditional oxidation methods. Recently developed homogeneous Cu/TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidinyl-N-oxyl) and related catalyst systems appear to fill this void. The reactions exhibit high levels of chemoselectivity and broad functional-group tolerance, and they often operate efficiently at room temperature with ambient air as the oxidant. These advances, together with their historical context and recent applications, are highlighted in this Minireview. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Greenhouse Gas Conversion by Homogeneous Salen Catalyst Systems under Very Mild Reaction Condition

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Hyungsock; Song, Sanghoon; Ahn, Sunghyun; Kim, Taesoon; Kim, Beomsik; Chang, Taesun [Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of)

    2013-08-15

    Homogeneous salen catalyt systems were investigated for the conversion of greenhouse gas into cyclic carbonate under room temperature and atmospheric pressure. Salen complexes were more active than salophen complexes. Neither electron withdrawing nor donating group showed lower conversion efficiency. Co-catalysts such as moisture or ammonium salt increased the conversion efficiency dramatically. These results have potential to decrease carbon dioxide emitted from fossil fuel combustions under mild condition. One of the main scientific challenges in the 21st century is the global warming due to the increasing level of carbon dioxide. The consumption of fossil fuels is continue to increase with emitting substantial amount of green house gas. The solution currently considered is capturing and storing of carbon dioxide which compressing carbon dioxide and then storing it into oil wells or under the ocean. The other solution include converting the carbon dioxide into useful chemicals with significant commercial demand, but low chemical reactivity of carbon dioxide restricts the chemical reactions.

  12. System and method for controlling ammonia levels in a selective catalytic reduction catalyst using a nitrogen oxide sensor

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-07-25

    A system according to the principles of the present disclosure includes an air/fuel ratio determination module and an emission level determination module. The air/fuel ratio determination module determines an air/fuel ratio based on input from an air/fuel ratio sensor positioned downstream from a three-way catalyst that is positioned upstream from a selective catalytic reduction (SCR) catalyst. The emission level determination module selects one of a predetermined value and an input based on the air/fuel ratio. The input is received from a nitrogen oxide sensor positioned downstream from the three-way catalyst. The emission level determination module determines an ammonia level based on the one of the predetermined value and the input received from the nitrogen oxide sensor.

  13. Development of a Practical Hydrogen Storage System Based on Liquid Organic Hydrogen Carriers and a Homogeneous Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Craig [Hawaii Hydrogen Carriers, LLC, Honolulu, HI (United States); Brayton, Daniel [Hawaii Hydrogen Carriers, LLC, Honolulu, HI (United States); Jorgensen, Scott W. [General Motors, LLC, Warren, MI (United States). Research and Development Center. Chemical and Material Systems Lab.; Hou, Peter [General Motors, LLC, Warren, MI (United States). Research and Development Center. Chemical and Material Systems Lab.

    2017-03-24

    The objectives of this project were: 1) optimize a hydrogen storage media based on LOC/homogeneous pincer catalyst (carried out at Hawaii Hydrogen Carriers, LLC) and 2) develop space, mass and energy efficient tank and reactor system to house and release hydrogen from the media (carried out at General Motor Research Center).

  14. Properties of La1-xCexCoO3 system perovskite-type catalysts for diesel engine exhaust removal

    Institute of Scientific and Technical Information of China (English)

    GONG Cairong; FAN Guoliang; HOU Yanfeng; SONG Chonglin; HUANG Qifei; ZHANG Zhongrong

    2007-01-01

    A series of complex oxide Lal-xCexCoO3 catalysts was synthesized at a low temperature through a combustion process,in which x is among 0,0.1,0.2,0.4 and 0.6 corresponding to the quantity of La3+ partial substitution by Ce4+ The catalysts were characterized for phase composition using chemical analysis and X-ray diffraction.The catalytic activity of the catalysts in removal of NOx,total hydrocarbon (THC)and particulate matter (PM) from diesel exhaust gases were examined in detail using temperature-programmed reaction technique.The results show that after partial substitution of La3+ with Ce4+,the oxygen vacancy concentration increases significantly and a Co3+-Co2~ system is formed.Consequently,the catalytic activity in the removal of THC and NOx is significantly improved.But for the PM,the effect is not so obvious.The possible catalytic mechanism for this was presented.It is also worth noting that the doped catalysts showed good stability.

  15. Zeolite Based SCR Catalysts - An Interesting Alternative To Vanadia-Titania Systems

    Energy Technology Data Exchange (ETDEWEB)

    Devadas, M.; Kroecher, O.; Wokaun, A.

    2004-03-01

    Metal exchanged zeolite catalysts were tested for the selective catalytic reduction of NO{sub x} with ammonia (NH{sub 3}-SCR) and compared with a vanadia based catalyst. With pure NO in the feed Cu-ZSM5 exhibited a better NO{sub x} conversion than Fe-ZSM5 and V{sub 2}O{sub 5}/WO{sub 3}-TiO{sub 2} at all temperatures. The main drawback of Cu-ZSM5 is the required excess of ammonia due to oxidation of NH{sub 3} to N{sub 2} (SCO). For a feed ratio of NO:NO{sub 2} = 0.5, all catalysts showed a high activity at elevated temperatures, but Fe-ZSM5 and Cu-ZSM5 performed better than the vanadia catalyst at lower temperatures. (author)

  16. A tuberculose no cotidiano médico e o efeito bumerangue do abandono Tuberculosis in day-to-day medical practice and the boomerang effect of neglect

    Directory of Open Access Journals (Sweden)

    Lia Selig

    2012-01-01

    Full Text Available O objetivo do estudo foi conhecer a percepção e os sentimentos dos médicos sobre a tuberculose (TB no Rio de Janeiro. Onze médicos de um hospital público de grande porte foram submetidos a uma entrevista semiestruturada. O processo investigativo teve como base a fenomenologia hermenêutica-dialética. As falas dos depoentes foram analisadas com o objetivo de identificar e compreender no seu discurso suas vivências sobre o seu viver-ser-estar-adoecer que estivessem relacionadas à TB. Dentre as categorias identificadas, o abandono foi abordado neste artigo em suas quatro dimensões: o respeito, a responsabilidade, as condições de atendimento e o mal-estar. Percebe-se o efeito bumerangue do abandono: aquele que abandona também é abandonado. Outros sentimentos referidos foram os de desmotivação, revolta e de frustração. É preocupante a saúde mental dos médicos submetidos à sobrecarga de trabalho e em condições inadequadas. Questiona-se como cuidadores nestas condições podem exercer sua função de cuidar. Concluímos que controlar a TB bem como alcançar os demais objetivos do SUS deve envolver uma política de recursos humanos que responda às questões apresentadas.The scope of this study was to understand the perceptions and feelings of physicians dealing with tuberculosis (TB in Rio de Janeiro. Eleven physicians working in a large public hospital were interviewed using a semi-structured questionnaire. The interpretation of the interviews was based on hermeneutic-dialectic phenomenology. The answers were analyzed in order to identify and understand their live TB-related experiences from their statements. Among the categories that emerged, neglect was chosen as the focus of this article in its four dimensions: respect, responsibility, conditions of care and discomfort. The boomerang effect of neglect was perceived during interviews with physicians: the one who neglects is also neglected. Other reported feelings included lack

  17. Structure and properties of molybdenum oxide nitrides as model systems for selective oxidation catalysts

    Directory of Open Access Journals (Sweden)

    Lerch Martin

    2011-07-01

    Full Text Available Abstract Molybdenum oxide nitride (denoted as Mo(O,N3 was obtained by ammonolysis of α-MoO3 with gaseous ammonia. Electronic and geometric structure, reducibility, and conductivity of Mo(O,N3 were investigated by XRD, XAS, UV-Vis spectroscopy, and impedance measurements. Catalytic performance in selective propene oxidation was determined by online mass spectrometry und gas chromatography. Upon incorporation of nitrogen, Mo(O,N3 maintained the characteristic layer structure of α-MoO3. XRD analysis showed an increased structural disorder in the layers while nitrogen is removed from the lattice of Mo(O,N3 at temperatures above ~600 K. Compared to regular α-MoO3, Mo(O,N3 exhibited a higher electronic and ionic conductivity and an onset of reduction in propene at lower temperatures. Surprisingly, α-MoO3 and Mo(O,N3 exhibited no detectable differences in onset temperatures of propene oxidation and catalytic selectivity or activity. Apparently, the increased reducibility, oxygen mobility, and conductivity of Mo(O,N3 compared to α-MoO3 had no effect on the catalytic behavior of the two catalysts. The results presented confirm the suitability of molybdenum oxide nitrides as model systems for studying bulk contributions to selective oxidation.

  18. Advanced cathode materials for polymer electrolyte fuel cells based on pt/ metal oxides: from model electrodes to catalyst systems.

    Science.gov (United States)

    Fabbri, Emiliana; Pătru, Alexandra; Rabis, Annett; Kötz, Rüdiger; Schmidt, Thomas J

    2014-01-01

    The development of stable catalyst systems for application at the cathode side of polymer electrolyte fuel cells (PEFCs) requires the substitution of the state-of-the-art carbon supports with materials showing high corrosion resistance in a strongly oxidizing environment. Metal oxides in their highest oxidation state can represent viable support materials for the next generation PEFC cathodes. In the present work a multilevel approach has been adopted to investigate the kinetics and the activity of Pt nanoparticles supported on SnO2-based metal oxides. Particularly, model electrodes made of SnO2 thin films supporting Pt nanoparticles, and porous catalyst systems made of Pt nanoparticles supported on Sb-doped SnO2 high surface area powders have been investigated. The present results indicate that SnO2-based supports do not modify the oxygen reduction reaction mechanism on the Pt nanoparticle surface, but rather lead to catalysts with enhanced specific activity compared to Pt/carbon systems. Different reasons for the enhancement in the specific activity are considered and discussed.

  19. Correction: A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide.

    Science.gov (United States)

    Ng, Chee Koon; Wu, Jie; Hor, T S Andy; Luo, He-Kuan

    2016-12-22

    Correction for 'A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide' by Chee Koon Ng et al., Chem. Commun., 2016, 52, 11842-11845.

  20. Assessment of microcapsule—catalyst particles healing system in high performance fibre reinforced polymer composite

    Science.gov (United States)

    Bolimowski, P. A.; Wass, D. F.; Bond, I. P.

    2016-08-01

    Autonomous self-healing in carbon fibre reinforced polymer (CFRP) is demonstrated using epoxy resin filled microcapsules and a solid-state catalyst. Microcapsules filled with oligomeric epoxy resin (20-450 μm) and particles of Sc(OTf)3 are embedded in an interleave region of a unidirectional CFRP laminate and tested under mode I loading. Double cantilever beam (DCB) test specimens containing variable concentrations of microcapsules and catalyst were prepared, tested and compared to those healed by manual injection with corresponding healing resin formulation. The healing efficiency was evaluated by comparing the maximum peak load recorded on load-displacement curves for pristine and healed specimens. A 44% maximum recovery was observed for specimens containing 10 wt% of solid phase catalyst and 11 wt% of epoxy microcapsules. However, a significant (80%) decrease in initial strain energy release rate (G IC) was observed for specimens with the embedded healing chemistries.

  1. Preparation of novel CdS-incorporated special glass composite as photocatalyst material used for catalyst-fixed system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Maochang; Jing, Dengwei; Zhao, Liang; Guo, Liejin [State Key Laboratory of Multiphase Flow, Xi' an Jiaotong University, Xi' an 710049 (China)

    2010-07-15

    A novel catalyst-fixed way is present. And two series of novel CdS-incorporated special glass composite photocatalysts working under visible light were successfully prepared in this way by a two-step thermal sulfidation procedure for the use of catalyst-fixed system. One was by a high temperature way, and the other was by a low temperature way. The composite photocatalysts with different content of CdS prepared by the methods were found to show a good activity for the decomposition of water under visible light. The highest rate of H{sub 2} revolution is 1549 {mu}mol/(hg{sub CdS}) with wt1%-Pt loaded. The composites prepared by high and low temperature were characterized by X-ray diffraction (XRD), diffuse reflectance UV-vis spectra and scanning electron microscopy (SEM). The as-prepared photocatalysts exhibited different photochemical and photophysical properties for the combined way between glass-base and CdS. The photochemical and photophysical properties were very important in the catalyst-fixed system used for large-scale hydrogen production. (author)

  2. Homogeneous catalysts

    CERN Document Server

    Chadwick, John C; Freixa, Zoraida; van Leeuwen, Piet W N M

    2011-01-01

    This first book to illuminate this important aspect of chemical synthesis improves the lifetime of catalysts, thus reducing material and saving energy, costs and waste.The international panel of expert authors describes the studies that have been conducted concerning the way homogeneous catalysts decompose, and the differences between homogeneous and heterogeneous catalysts. The result is a ready reference for organic, catalytic, polymer and complex chemists, as well as those working in industry and with/on organometallics.

  3. A highly versatile catalyst system for the cross-coupling of aryl chlorides and amines.

    Science.gov (United States)

    Lundgren, Rylan J; Sappong-Kumankumah, Antonia; Stradiotto, Mark

    2010-02-08

    The syntheses of 2-(di-tert-butylphosphino)-N,N-dimethylaniline (L1, 71%) and 2-(di-1-adamantylphosphino)-N,N-dimethylaniline (L2, 74 %), and their application in Buchwald-Hartwig amination, are reported. In combination with [Pd(allyl)Cl](2) or [Pd(cinnamyl)Cl](2), these structurally simple and air-stable P,N ligands enable the cross-coupling of aryl and heteroaryl chlorides, including those bearing as substituents enolizable ketones, ethers, esters, carboxylic acids, phenols, alcohols, olefins, amides, and halogens, to a diverse range of amine and related substrates that includes primary alkyl- and arylamines, cyclic and acyclic secondary amines, N-H imines, hydrazones, lithium amide, and ammonia. In many cases, the reactions can be performed at low catalyst loadings (0.5-0.02 mol % Pd) with excellent functional group tolerance and chemoselectivity. Examples of cross-coupling reactions involving 1,4-bromochlorobenzene and iodobenzene are also reported. Under similar conditions, inferior catalytic performance was achieved when using Pd(OAc)(2), PdCl(2), [PdCl(2)(cod)] (cod = 1,5-cyclooctadiene), [PdCl(2)(MeCN)(2)], or [Pd(2)(dba)(3)] (dba = dibenzylideneacetone) in combination with L1 or L2, or by use of [Pd(allyl)Cl](2) or [Pd(cinnamyl)Cl](2) with variants of L1 and L2 bearing less basic or less sterically demanding substituents on phosphorus or lacking an ortho-dimethylamino fragment. Given current limitations associated with established ligand classes with regard to maintaining high activity across the diverse possible range of C-N coupling applications, L1 and L2 represent unusually versatile ligand systems for the cross-coupling of aryl chlorides and amines.

  4. An innovative catalyst system for slurry-phase Fischer-Tropsch synthesis: Cobalt plus a water-gas-shift catalyst. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Satterfield, C.N.; Yates, I.C.; Chanenchuk, C.

    1991-07-01

    The feasibility of using a mechanical mixture of a Co/MgO/SiO{sub 2} Fischer-Tropsch catalyst and a Cu-ZnO/Al{sub 2}O{sub 3} water-gas-shift (WGS) catalyst for hydrocarbon synthesis in a slurry reactor has been established. Such a mixture can combine the superior product distribution from cobalt with the high activity for the WGS reaction characteristic of iron. Weight ratios of Co/MgO/SiO{sub 2} to Cu-ZnO/Al{sub 2}O{sub 3} of 0.27 and 0.51 for the two catalysts were studied at 240{degrees}C, 0.79 MPa, and in situ H{sub 2}/CO ratios between 0.8 and 3.0. Each catalyst mixture showed stable Fischer-Tropsch activity for about 400 hours-on-stream at a level comparable to the cobalt catalyst operating alone. The Cu-ZnO/Al{sub 2}O{sub 3} catalyst exhibited a very slow loss of activity under these conditions, but when operated alone it was stable in a slurry reactor at 200--220{degrees}C, 0.79--1.48 MPa, and H{sub 2}/CO in situ ratios between 1.0 and 2.0. The presence of the water-gas-shift catalyst did not affect the long-term stability of the primary Fischer-Tropsch selectivity, but did increase the extent of secondary reactions, such as l-alkene hydrogenation and isomerization.

  5. CONFIGURATION OF VO(OR)2Cl-Al(i-Bu)3 CATALYST SYSTEM AND CHARGE DISTRIBUTION OF VANADIUM CENTRAL ION

    Institute of Scientific and Technical Information of China (English)

    JIAO Shuke; LU Chongxian; JIANG Jian

    1987-01-01

    According to the calculation of quantum chemistry it could be deduced that configurations of the catalysts VO(OR)2Cl-Al (i-Bu)3, for the alternating copolymerization of butadiene with propene, the highest reactive configuration was A. When the catalyst complex forms the configuration A, the energy of the system was the lowest; the central vanadium atom had relatively high positive charge and whose frontier orbital overlapped easily with the frontier orbital of butadiene to form coordination complex, so it was concluded from the experimental results and calculations that the configuration of the catalyst of relatively high activity was A.

  6. In situ synthesis of nano clay filled polyethylene using polymer support metallocenes catalyst system

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, Z.V.P.; Parikh, Parimal A., E-mail: zvpm@ched.svnit.ac.in [Sardar Vallabhbhai National Institute of Technology, Gujarat (India). Chemical Engineering Department; Rajesh, Smitha [Sardar Vallabhbhai National Institute of Technology, Gujarat (India). Sardar Vallabhbhai National Institute of Technology. Chemical Engineering Department

    2011-07-01

    In situ ethylene polymerizations were performed using bis(cyclopentadiene)titanium dichloride supported on poly ethersulfone as catalyst. The bis(cyclopentadiene)titanium dichloride supported on poly ethersulfone catalyst activity estimated by ethylene polymerization was 360 kg PE/mol Ti/h. During polymerization the fillers used were montmorillonite nano clays having surface modifications with 35-45 wt % dimethyl dialkyl(14-18)amine (FA) and 25-30 wt % trimethyl stearyl ammonium (FB). These fillers were pretreated with methylaluminoxine (MAO; co catalyst) for better dispersion onto the polymer matrix. The formation of polyethylene within the whole matrix was confirmed by FTIR studies. It was found that the nature of nano filler did not have any remarkable effect on the melting characteristics of the polymer. TGA study indicates that nano clay FB filled polyethylene has higher thermal stability than nano clay FA filled polyethylene. The melting temperature of the obtained polyethylenes was 142 degree C, which corresponds to that synthesized by the polyether sulfone supported catalyst. (author)

  7. Direct transformation of xylan-type hemicelluloses to furfural via SnCl₄ catalysts in aqueous and biphasic systems.

    Science.gov (United States)

    Wang, Wenju; Ren, Junli; Li, Huiling; Deng, Aojie; Sun, Runcang

    2015-05-01

    Direct catalytic transformation of xylan-type hemicelluloses to furfural in the aqueous system and the biphasic system were comparatively investigated under mild conditions. Screening of several promising chlorides for conversion of beech xylan in the aqueous system revealed the Lewis acid SnCl4 was the most effective catalyst. Comparing to the single aqueous system, the bio-based 2-methyltetrahydrofuran (2-MTHF)/H2O biphasic system was more conducive to the synthesis of furfural, in which the highest furfural yield of 78.1% was achieved by using SnCl4 as catalysts under the optimized reaction conditions (150°C, 120 min). Additionally, the influences of xylan-type hemicelluloses with different chemical and structural features from beech, corncob and bagasse on the furfural production were studied. It was found that furfural yield to some extent was determined by the xylose content in hemicelluloses and also had relationships with the molecular weight of hemicelluloses and the degree of crystallization.

  8. The Coldest Object in the Universe: Probing the Mass Distribution of the Ultra-Cold Outflow and Dusty Disk in the Boomerang Nebula

    Science.gov (United States)

    Sahai, R.; Vlemmings, W.; Nyman, L.

    2015-12-01

    Our Cycle 0 ALMA observations confirmed that the Boomerang Nebula is the coldest known object in the Universe, with a massive high-speed outflow that has cooled significantly below the temperature of the cosmic background (CMB). The Boomerang's prodigious mass-loss rate (0.001M⊙) and low-luminosity (300L⊙) make it a key object for understanding the remarkable transition of the circumstellar envelopes of AGB stars into bipolar planetary nebulae. We have obtained new ACA CO 1-0 data that recover much of the flux lost in the Cycle 0 data, and reveal heretofore unseen distant regions of the ultra-cold outflow re-heated to temperatures above the CMB. Our CO J=3-2 data reveal the precise, highly collimated shape of an inner bipolar structure and its dense central waist, with unprecedented angular resolution (0.4”). The waist shows a core-halo structure in the thermal dust emission at 0.88 mm, and its derived flux at this wavelength, compared with the 3.3, 2.6, and 1.3 mm fluxes support the presence of about 5×10-4 M⊙ of very large (˜mm-sized), cold (˜30K) grains. We also find the unexpected presence of weak SO emission, possibly resulting from the release of S from grains due to high-speed shocks.

  9. The Coldest Object in the Universe: Probing the Mass Distribution of the Ultra-Cold Outflow and Dusty Disk in the Boomerang Nebula

    Science.gov (United States)

    Sahai, R.; Vlemmings, W.; Nyman, L. A.

    2014-01-01

    Our Cycle 0 ALMA observations confirmed that the Boomerang Nebula is the coldest known object in the universe, with a massive high-speed outflow that has cooled significantly below the temperature of the cosmic background (CMB). The Boomerang's prodigious mass-loss rate (0.001 solar mass M yr (exp -1) and low-luminosity (300L ) make it a key object for understanding the remarkable transition of the circumstellar envelopes of AGB stars into bipolar planetary nebulae. We have obtained new ACA CO 1-0 data that recover much of the flux lost in the Cycle O data, and reveal heretofore unseen distant regions of the ultra-cold outflow reheated to temperatures above the CMB. Our CO J=3-2 data reveal the precise, highly collimated shape of an inner bipolar structure and its dense central waist, with unprecedented angular resolution (0.4 in). The waist shows a core-halo structure in the thermal dust emission at 0.88 millimeter, and its derived flux at this wavelength, compared with the 3.3, 2.6, and 1.3 millimeter fluxes support the presence of about 5 x 10 (exp -4) solar mass of very large (approximately millimeter-sized), cold (approximately 30K) grains. We also find the unexpected presence of weak SO emission, possibly resulting from the release of S from grains due to high-speed shocks.

  10. High-Activity Dealloyed Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kongkanand, Anusorn [General Motors LLC, Pontiac, MI (United States)

    2014-09-30

    Reduction of costly Pt usage in proton exchange membrane fuel cell electrodes is one of the major challenges towards development and commercialization of fuel cell vehicles. Although few have met the initial-kinetic activity requirements in a realistic fuel cell device, no catalyst material has ever met the demanding fuel cell durability targets set by DOE. In this project, a team of 4 universities and 2 companies came together to investigate a concept that appeared promising in preliminary non-fuel cell tests then to further develop the catalyst to a mature level ready for vehicle implementation. The team consists of academia with technical leadership in their respective areas, a catalyst supplier, and a fuel cell system integrator.The tightly collaborative project enabled development of a highly active and durable catalyst with performance that significantly exceeds that of previous catalysts and meets the DOE targets for the first time (Figure 1A). The catalyst was then further evaluated in full-active-area stack in a realistic vehicle operating condition (Figure 1B). This is the first public demonstration that one can realize the performance benefit and Pt cost reduction over a conventional pure Pt catalyst in a long-term realistic PEMFC system. Furthermore, systematic analyses of a range of catalysts with different performance after fuel cell testing allowed for correlation between catalyst microstructure and its electrocatalytic activity and durability. This will in turn aid future catalyst development.

  11. SU-E-T-350: Verification of Gating Performance of a New Elekta Gating Solution: Response Kit and Catalyst System

    Energy Technology Data Exchange (ETDEWEB)

    Xie, X; Cao, D; Housley, D; Mehta, V; Shepard, D [Swedish Cancer Institute, Seattle, WA (United States)

    2014-06-01

    Purpose: In this work, we have tested the performance of new respiratory gating solutions for Elekta linacs. These solutions include the Response gating and the C-RAD Catalyst surface mapping system.Verification measurements have been performed for a series of clinical cases. We also examined the beam on latency of the system and its impact on delivery efficiency. Methods: To verify the benefits of tighter gating windows, a Quasar Respiratory Motion Platform was used. Its vertical-motion plate acted as a respiration surrogate and was tracked by the Catalyst system to generate gating signals. A MatriXX ion-chamber array was mounted on its longitudinal-moving platform. Clinical plans are delivered to a stationary and moving Matrix array at 100%, 50% and 30% gating windows and gamma scores were calculated comparing moving delivery results to the stationary result. It is important to note that as one moves to tighter gating windows, the delivery efficiency will be impacted by the linac's beam-on latency. Using a specialized software package, we generated beam-on signals of lengths of 1000ms, 600ms, 450ms, 400ms, 350ms and 300ms. As the gating windows get tighter, one can expect to reach a point where the dose rate will fall to nearly zero, indicating that the gating window is close to beam-on latency. A clinically useful gating window needs to be significantly longer than the latency for the linac. Results: As expected, the use of tighter gating windows improved delivery accuracy. However, a lower limit of the gating window, largely defined by linac beam-on latency, exists at around 300ms. Conclusion: The Response gating kit, combined with the C-RAD Catalyst, provides an effective solution for respiratorygated treatment delivery. Careful patient selection, gating window design, even visual/audio coaching may be necessary to ensure both delivery quality and efficiency. This research project is funded by Elekta.

  12. Evaluation of PEMFC System Contaminants on the Performance of Pt Catalyst via Cyclic Voltammetry: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Macomber, C.; Dinh, H. N.

    2012-07-01

    Using electrochemical cyclic voltammetry as a quick ex-situ screening tool, the impact of the extracted solution and the individual leachable constituents from prospective BOP component materials on the performance and recoverability of the platinum catalyst were evaluated. Taking an extract from Zytel{trademark} HTN51G35HSLR (PPA) as an example, the major leachable organic components are caprolactam and 1,6 hexanediol. While these organic compounds by themselves do poison the Pt catalyst to some extent, such influence is mostly recoverable by means of potential holding and potential cycling. The extracted solution, however, shows a more drastic poisoning effect and it was not recoverable. Therefore the non-recoverable poisoning effect observed for the extracted solution is not from the two organic species studied. This demonstrates the complexity of such a contaminant study. Inorganic compounds that are known poisons like sulfur even in very low concentrations, may have a more dominant effect on the Pt catalyst and the recoverability.

  13. Design of highly active binary catalyst systems for CO2/epoxide copolymerization: polymer selectivity, enantioselectivity, and stereochemistry control.

    Science.gov (United States)

    Lu, Xiao-Bing; Shi, Lei; Wang, Yi-Ming; Zhang, Rong; Zhang, Ying-Ju; Peng, Xiao-Jun; Zhang, Zhi-Chao; Li, Bo

    2006-02-01

    Asymmetric, regio- and stereoselective alternating copolymerization of CO(2) and racemic aliphatic epoxides proceeds effectively under mild temperature and pressure by using a binary catalyst system of a chiral tetradentate Schiff base cobalt complex [SalenCo(III)X] as the electrophile in conjunction with an ionic organic ammonium salt or a sterically hindered strong organic base as the nucleophile. The substituent groups on the aromatic rings, chiral diamine backbone, and axial X group of the electrophile, as well as the nucleophilicity, leaving ability, and coordination ability of the nucleophile, all significantly affect the catalyst activity, polymer selectivity, enantioselectivity, and stereochemistry. A bulky chiral cyclohexenediimine backbone complex [SalcyCo(III)X] with an axial X group of poor leaving ability as the electrophile, combined with a bulky nuclephile with poor leaving ability and low coordination ability, is an ideal binary catalyst system for the copolymerization of CO(2) and a racemic aliphatic epoxide to selectively produce polycarbonates with relatively high enantioselectivity, >95% head-to-tail connectivity, and >99% carbonate linkages. A fast copolymerization of CO(2) and epoxides was observed when the concentration of the electrophile or/and the nucleophile was increased, and the number of polycarbonate chains was proportional to the concentration of the nucleophile. Electrospray ionization mass spectrometry, in combination with a kinetic study, showed that the copolymerization involved the coordination activation of the monomer by the electrophile and polymer chain growth predominately occurring in the nucleophile. Both the enantiomorphic site effect resulting from the chiral electrophile and the polymer chain end effect mainly from the bulky nucleophile cooperatively control the stereochemistry of the CO(2)/epoxide copolymerization.

  14. Hydrogenation of Olefins Catalyzed by Highly Active Titanocene/NaH or n-BuLi Catalyst Systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effects of the substituents on the cyclopentadienyl ring and the reducing agents on the catalytic activity and the stability of titanocene/NaH or n-BuLi systems for the hydrogenation of olefins were investigated. For the catalyst systems composed of titanocene/NaH or n-BuLi, the nature and the number of the substituents on the cyclopentadienyl ring control the catalytic behavior of those two systems. The effect of the reducing agent on the catalytic activity is relatively small. In addition, the characters of the hydrogenation of various olefins catalyzed respectively by Cp2TiCl2/NaH or n-BuLi systems were compared.

  15. Catalyst mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Masel, Richard I.; Rosen, Brian A.

    2017-02-14

    Catalysts that include at least one catalytically active element and one helper catalyst can be used to increase the rate or lower the overpotential of chemical reactions. The helper catalyst can simultaneously act as a director molecule, suppressing undesired reactions and thus increasing selectivity toward the desired reaction. These catalysts can be useful for a variety of chemical reactions including, in particular, the electrochemical conversion of CO.sub.2 or formic acid. The catalysts can also suppress H.sub.2 evolution, permitting electrochemical cell operation at potentials below RHE. Chemical processes and devices using the catalysts are also disclosed, including processes to produce CO, OH.sup.-, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, O.sub.2, H.sub.2, (COOH).sub.2, or (COO.sup.-).sub.2, and a specific device, namely, a CO.sub.2 sensor.

  16. Insights into the Mechanism of a Covalently Linked Organic Dye-Cobaloxime Catalyst System for Dye-Sensitized Solar Fuel Devices.

    Science.gov (United States)

    Pati, Palas Baran; Zhang, Lei; Philippe, Bertrand; Fernández-Terán, Ricardo; Ahmadi, Sareh; Tian, Lei; Rensmo, Håkan; Hammarström, Leif; Tian, Haining

    2017-06-09

    A covalently linked organic dye-cobaloxime catalyst system based on mesoporous NiO is synthesized by a facile click reaction for mechanistic studies and application in a dye-sensitized solar fuel device. The system is systematically investigated by photoelectrochemical measurements, density functional theory, time-resolved fluorescence, transient absorption spectroscopy, and photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer process to reduce the catalyst. Moreover, the dye adopts different structures with different excited state energies, and excitation energy transfer occurs between neighboring molecules on the semiconductor surface. The photoelectrochemical experiments also show hydrogen production by this system. The axial chloride ligands of the catalyst are released during photocatalysis to create the active sites for proton reduction. A working mechanism of the dye-catalyst system on the photocathode is proposed on the basis of this study. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  17. Stabilized rhodium(0) nanoparticles: a reusable hydrogenation catalyst for arene derivatives in a biphasic water-liquid system.

    Science.gov (United States)

    Schulz, J; Roucoux, A; Patin, H

    2000-02-18

    A colloidal system based on an aqueous suspension of rhodium(o) nanoparticles proved to be an efficient catalyst for the hydrogenation of arene derivatives under biphasic conditions. The rhodium nanoparticles (2-2.5 nm) were synthesized by the reduction of RhCl3 x 3H2O with sodium borohydride and were stabilized by highly water-soluble N-alkyl-N-(2-hydroxyethyl)ammonium salts (HEA-Cn). These surfactant molecules were characterized by measurements of the surface tension and the aqueous dispersions with rhodium were observed by transmission electron cryomicroscopy. The catalytic system is efficient under ultramild conditions, namely room temperature and 1 atm H2 pressure. The aqueous phase which contains the protected rhodium(0) colloids can be reused without significant loss of activity. The microheterogeneous behavior of this catalytic system was confirmed on a mercury poisoning experiment.

  18. Nanoscale zero-valent iron/AC as heterogeneous Fenton catalysts in three-dimensional electrode system.

    Science.gov (United States)

    Zhang, Chao; Zhou, Lei; Yang, Jie; Yu, Xinmin; Jiang, Yonghai; Zhou, Minghua

    2014-01-01

    In the present work, nanoscale zero-valent iron/activated carbon (NZVI/AC) was investigated as heterogeneous Fenton catalyst in three-dimensional (3D) electrode system for methyl orange (MO) degradation. Some important operating parameters such as cathodic potential, pH, and O₂ flow rate were investigated, exhibiting good decolorization. The mineralization of MO was significantly improved by 20-35% compared to two-dimensional (2D) AC system at the optimum conditions. Although the TOC removal of AC was higher than NZVI/AC due to its good adsorption capacity initially, heterogeneous Fenton catalysis played a more and more important roles in the following test. After eight runs, NZVI/AC still exhibited excellent catalytic properties with low iron leaching. Further, a relatively comprehensive mechanism of NZVI/AC as particle electrodes in 3D system was proposed.

  19. Development of Optimal Catalyst Designs and Operating Strategies for Lean NOx Reduction in Coupled LNT-SCR Systems

    Energy Technology Data Exchange (ETDEWEB)

    Harold, Michael; Crocker, Mark; Balakotaiah, Vemuri; Luss, Dan; Choi, Jae-Soon; Dearth, Mark; McCabe, Bob; Theis, Joe

    2013-09-30

    Oxides of nitrogen in the form of nitric oxide (NO) and nitrogen dioxide (NO{sub 2}) commonly referred to as NO{sub x}, is one of the two chemical precursors that lead to ground-level ozone, a ubiquitous air pollutant in urban areas. A major source of NO{sub x} is generated by equipment and vehicles powered by diesel engines, which have a combustion exhaust that contains NO{sub x} in the presence of excess O{sub 2}. Catalytic abatement measures that are effective for gasoline-fueled engines such as the precious metal containing three-way catalytic converter (TWC) cannot be used to treat O2-laden exhaust containing NO{sub x}. Two catalytic technologies that have emerged as effective for NO{sub x} abatement are NO{sub x} storage and reduction (NSR) and selective catalytic reduction (SCR). NSR is similar to TWC but requires much larger quantities of expensive precious metals and sophisticated periodic switching operation, while SCR requires an on-board source of ammonia which serves as the chemical reductant of the NO{sub x}. The fact that NSR produces ammonia as a byproduct while SCR requires ammonia to work has led to interest in combining the two together to avoid the need for the cumbersome ammonia generation system. In this project a comprehensive study was carried out of the fundamental aspects and application feasibility of combined NSR/SCR. The project team, which included university, industry, and national lab researchers, investigated the kinetics and mechanistic features of the underlying chemistry in the lean NOx trap (LNT) wherein NSR was carried out, with particular focus on identifying the operating conditions such as temperature and catalytic properties which lead to the production of ammonia in the LNT. The performance features of SCR on both model and commercial catalysts focused on the synergy between the LNT and SCR converters in terms of utilizing the upstream-generated ammonia and alternative reductants such as propylene, representing the

  20. Ionic Liquid-Complex Pd/C System as Catalyst for Copolymerization of CO and Styrene

    Institute of Scientific and Technical Information of China (English)

    王海霞; 郭锦棠; 胡光; 冯亚凯; 武瑞涛

    2014-01-01

    The copolymerization of CO and styrene catalyzed by Pd/C toward the formation of polyketones (PK)was studied in the N-valeronitrile-N'-methylimidazolium hexafluorophosphate ([C4CNmim]+PF6-) medium. The synthe-sized PK was characterized by Fourier transform infrared(FTIR), elemental analysis, 13C-nuclear magnetic resonance (13C-NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and gel permeation chro-matography (GPC). The supported ionic liquid film on the surface of Pd/C catalyst can prevent the products from covering the hole of active carbon due to its chemical stability and weak coordination ability with metal ions, and thus efficiently improve the catalytic activity. The effects of different amounts of ionic liquid on the catalytic activity and reusability of the catalyst and the molecular weight of PK were discussed. When the usage of ionic liquid is 10wt%(0.1 g ionic liquid/1 g active carbon carrier) and the theoretical content of Pd2+is 5wt%(0.05 g Pd2+/1 g active car-bon carrier), the highest catalytic activity 2 963.64 gSTCO/(gPd·h) is achieved with the molecular weight and polydispersity index of PK as Mn=9 684, Mw=13 452 and Mw/Mn=1.389.

  1. Carbon nanohybrids used as catalysts and emulsifiers for reactions in biphasic aqueous/organic systems

    Institute of Scientific and Technical Information of China (English)

    Daniel E. Resasco

    2014-01-01

    This mini-review summarizes some novel aspects of reactions conducted in aqueous/organic emul-sions stabilized by carbon nanohybrids functionalized with catalytic species. Carbon nanohybrids represent a family of solid catalysts that not only can stabilize water-oil emulsions in the same fash-ion as Pickering emulsions, but also catalyze reactions at the liquid/liquid interface. Several exam-ples are discussed in this mini-review. They include (a) aldol condensation-hydrodeoxygenation tandem reactions catalyzed by basic (MgO) and metal (Pd) catalysts, respectively; (b) Fischer-Tropsch synthesis catalyzed by carbon-nanotube-supported Ru;and (c) emulsion polymerization of styrene for the production of conductive polymer composites. Conducting these reactions in emul-sion generates important advantages, such as increased liquid/liquid interfacial area that conse-quently means faster mass transfer rates of molecules between the two phases, effective separation of products from the reaction mixture by differences in the water-oil solubility, and significant changes in product selectivity that can be adjusted by modifying the emulsion characteristics.

  2. Transition Metal Catalyzed Hydroarylation of Multiple Bonds: Exploration of Second Generation Ruthenium Catalysts and Extension to Copper Systems

    Energy Technology Data Exchange (ETDEWEB)

    T. Brent Gunnoe

    2011-02-17

    Catalysts provide foundational technology for the development of new materials and can enhance the efficiency of routes to known materials. New catalyst technologies offer the possibility of reducing energy and raw material consumption as well as enabling chemical processes with a lower environmental impact. The rising demand and expense of fossil resources has strained national and global economies and has increased the importance of accessing more efficient catalytic processes for the conversion of hydrocarbons to useful products. The goals of the research are to develop and understand single-site homogeneous catalysts for the conversion of readily available hydrocarbons into useful materials. A detailed understanding of these catalytic reactions could lead to the development of catalysts with improved activity, longevity and selectivity. Such transformations could reduce the environmental impact of hydrocarbon functionalization, conserve energy and valuable fossil resources and provide new technologies for the production of liquid fuels. This project is a collaborative effort that incorporates both experimental and computational studies to understand the details of transition metal catalyzed C-H activation and C-C bond forming reactions with olefins. Accomplishments of the current funding period include: (1) We have completed and published studies of C-H activation and catalytic olefin hydroarylation by TpRu{l_brace}P(pyr){sub 3}{r_brace}(NCMe)R (pyr = N-pyrrolyl) complexes. While these systems efficiently initiate stoichiometric benzene C-H activation, catalytic olefin hydroarylation is hindered by inhibition of olefin coordination, which is a result of the steric bulk of the P(pyr){sub 3} ligand. (2) We have extended our studies of catalytic olefin hydroarylation by TpRu(L)(NCMe)Ph systems to L = P(OCH{sub 2}){sub 3}CEt. Thus, we have now completed detailed mechanistic studies of four systems with L = CO, PMe{sub 3}, P(pyr){sub 3} and P(OCH{sub 2}){sub 3}CEt

  3. Improved Automotive NO (x) Aftertreatment System: Metal Ammine Complexes as NH3 Source for SCR Using Fe-Containing Zeolite Catalysts

    DEFF Research Database (Denmark)

    Johannessen, Tue; Schmidt, Henning; Frey, Anne Mette

    2009-01-01

    Ammonia storage is a challenge in the selective catalytic reduction of NO (x) in vehicles. We propose a new system, based on metal ammines as the ammonia source. In combination with iron containing zeolites as the SCR catalyst it should be possible to obtain a low temperature system for NO (x...

  4. Exploring the cooperation effect of DBD byproducts and Ag/TiO2 catalyst for water treatment in an APPJ system

    Science.gov (United States)

    Guangliang, Chen; Wei, Hu; Jinsong, Yu; Wenxia, Chen; Jun, Huang

    2017-01-01

    In this paper, the collective effects of combining heterogeneous Ag/TiO2 nanocomposite catalyst with the byproducts (primarily the irradiation and the O3 species) of an atmospheric pressure plasma jet (APPJ) system on the degradation of methyl orange (MO) were explored. The heterostructured Ag/TiO2 nanocomposite was achieved via decorating the Ag quantum dots (QDs) on the commercially available TiO2 catalyst (P25) through a hydrothermal method. The x-ray diffraction analysis of the nanocomposite catalyst showed the diffraction peaks at 44.3°, 64.4°, and 77.5°, corresponding to the Ag planes of (200), (220) and (311), respectively. The high resolution transmission electron microscope characterization of the nanocomposite catalyst indicated that the Ag QDs with an average diameter of 5 nm were homogeneously distributed on the P25 surface. The experimental results on the MO photodegradation showed that the APPJ irradiation had a marginal effect on the cleavage of the MO molecules. When the Ag/TiO2 nanocomposite catalyst was used, the photodegradation rate of MO increased about 5 times. When both the APPJ byproducts and the Ag/TiO2 nanocomposite catalyst were used, however, over 90% of the MO in the tested solution was cleaved within 15 min, and the energy efficiency was about 0.6 g/kW h. Moreover, an optimal Ag dosage value was determined (6 wt%). The catalytic results indicated that combining the DBD plasma byproducts with heterogeneous nanocomposite catalysts may be an effect protocol for decreasing the application cost of the DBD system and mitigating the environment pollution by organic dyes in the textile industry.

  5. Boomeranging in structural defense: phytophagous insect uses cycad trichomes to defend against entomophagy.

    Science.gov (United States)

    Marler, Thomas E

    2012-11-01

    Plant defensive behaviors that resist arthropod herbivory include trichome-mediated defenses, and variation in plant trichome morphology and abundance provides examples of the mechanistic complexities of insect-plant interactions. Trichomes were removed from Cycas revoluta cataphylls on the island of Guam to reveal Aulacaspis yasumatsui scale infestation, and predation of the newly exposed insects by pre-existing Rhyzobius lophanthae beetles commenced within one day. The quotient of predated/total scale insects was 0.5 by day 4 and stabilized at that found on adjacent glabrous leaves in about one week. The trichome phenotype covering the C. revoluta cataphyll complex offers the invasive A. yasumatsui armored scale effectual enemy-free space in this system. This pest and predator share no known evolutionary history with C. revoluta, therefore, the adaptive significance of this plant behavior in natural habitat is not yet known.

  6. Evaluation of SiO2 sonogels, prepared by a new catalyst-free method, as drug delivery system.

    Science.gov (United States)

    Piñón-Segundo, Elizabeth; Ganem-Quintanar, Adriana; Flores-Flores, José Ocotlán; Saniger-Blesa, José Manuel; Urbán-Morlán, María Zaida; Mendoza-Romero, Luis; Nava-Arzaluz, María Guadalupe; Quintanar-Guerrero, David

    2008-08-01

    Recently, we reported on the synthesis of catalyst-free SiO(2) sonogels prepared by the sonication of a neutral distilled water/ tetraethyl ortosilicate mixture. The purpose of the present study was to evaluate the feasibility of using these sonogels as pharmaceutical delivery systems. A certified color additive (sunset yellow, SY) was used as a model compound for the release experiments. Different amounts of dye were incorporated into the gels before drying. Sonogels were characterized by scanning electron microscopy and differential scanning calorimetry. The effect of three drying temperatures (25 degrees C, 40 degrees C and 80 degrees C) and two mean grain sizes (1125 and 630 microm) on release behavior was analyzed. The analysis of variance showed no significant differences between the Higuchi's constants (K(H)) obtained for SY-loaded sonogels dried at 80 degrees C with different SY loads, irrespective of the mean grain size. In contrast, for SY-loaded sonogels dried at 40 degrees C, differences were found between sonogels loaded with 2.7, 7.7, 12.2, and 18.2% of SY, and no significant differences were detected between the mean grain sizes analyzed. Considering that the preparation of sonogels by the catalyst-free method allows an easy encapsulation, sonogels may offer an interesting alternative for drug release in the pharmaceutical field.

  7. Highly dispersed metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Xin; West, William L.; Rhodes, William D.

    2016-11-08

    A supported catalyst having an atomic level single atom structure is provided such that substantially all the catalyst is available for catalytic function. A process of forming a single atom catalyst unto a porous catalyst support is also provided.

  8. Catalyst Architecture

    DEFF Research Database (Denmark)

    Kiib, Hans; Marling, Gitte; Hansen, Peter Mandal

    2014-01-01

    How can architecture promote the enriching experiences of the tolerant, the democratic, and the learning city - a city worth living in, worth supporting and worth investing in? Catalyst Architecture comprises architectural projects, which, by virtue of their location, context and their combination...... of programs, have a role in mediating positive social and/or cultural development. In this sense, we talk about architecture as a catalyst for: sustainable adaptation of the city’s infrastructure appropriate renovation of dilapidated urban districts strengthening of social cohesiveness in the city development...

  9. Dynamics of Catalyst Nanoparticles

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Cavalca, Filippo; Wagner, Jakob Birkedal

    under gas exposure, dynamic phenomena such as sintering and growth can be observed with sub-Ångstrøm resolution. Metal nanoparticles contain the active sites in heterogeneous catalysts, which are important for many industrial applications including the production of clean fuels, chemicals...... and pharmaceuticals, and the cleanup of exhaust from automobiles and stationary power plants. Sintering, or thermal deactivation, is an important mechanism for the loss of catalyst activity. In order to initiate a systematic study of the dynamics and sintering of nanoparticles, various catalytic systems have been...

  10. New 'Foucaultdian Boomerangs'

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2016-01-01

    This paper uses the metaphor of ‘boomerangs’ articulated by Michel Foucault to discuss the potential for drones to become the ‘next layer’ of urban surveillance in our cities. Like earlier Western technologies and techniques of government that were ‘tested out’ in foreign warzones and then ‘brought...... to Western cities. The paper explores how a nexus of Surveillance Studies and mobilities research may be a fruitful way into comprehending this new phenomenon. En route the practical applications of drones as well as the historical importance of aerial power are connected to a situational understanding...

  11. New 'Foucaultdian Boomerangs'

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    as ‘mobilites design’ for the contemporary network city (Jensen, 2014) and drones as yet another potential ‘tool’ in the ICT toolbox of urban planners and designers (Jensen in press). En route to this discussion I will explore the idea that urban surveillance drones may be comprehended as a new dimension...... of ‘mobilities design’ (Jensen, 2014). By marrying surveillance studies and mobilities theories I explore the potential of such new framing to increase our understanding of drone technologies in future urban societies. The paper is structured in six sections. After the introduction in section one, I move......Contemporary drone technology (here defined as unmanned and remote controlled flying devices capable of transmitting long-distance surveillance information as well as carrying weapons) raises international debate about ethical issues related to ’kills at a distance’ policies carried out by US...

  12. Exploring the Boomerang Effect

    DEFF Research Database (Denmark)

    Laursen, Keld; Leone, M. Isabella; Moreira, Solon

    Licensing is one of the most commonly observed inter-firm contractual agreements.Drawing on the resource-based view of the firm and contract economics, we argue that the inclusion of a grant-back clause in licensing agreements emerges as a consequence of the licensor and licensee firms’ requireme...

  13. New 'Foucaultdian Boomerangs'

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    and environmental surveillance of remote areas. In this paper I will set the agenda for doing two things. One is to explore the potential and scenarios related to the utilization of drone technologies in urban space surveillance (ITS/traffic control, crime prevention etc.). Like GPS that was developed for warfare...... are living within these huge human-made artefacts called ‘cities’. Therefore one may assume that the interest (commercial as well as governmental) for utilizing these new technologies for crowd surveillance and general population control will be increasing. Two decades ago urban scholar Mike Davies claimed......, 2006; Jensen, 2013; Urry, 2000, 2007, 2014). The framing of these technologies will touch upon modern warfare and ‘air power’ (Kaplan, 2006), militarization of urban space (Graham, 2010), ‘dark sides’ of mobilities (Jensen, 2013) as well as point towards a discussion about drone technologies...

  14. Evading the Boomerang Effect

    DEFF Research Database (Denmark)

    Laursen, Keld; Moreira, Solon; Reichstein, Toke

    2017-01-01

    Technology licensing agreements potentially can create future appropriability problems. Drawing on the appropriability literature, we argue that the inclusion of a grant-back clause in technology licensing agreements is an attempt to balance the gains from and protection of the focal firms’ techn...

  15. Ultrasound assisted free radical polymerization of glycidyl methacrylate by a new disite phase-transfer catalyst system: A kinetic study.

    Science.gov (United States)

    Sankar, Kavitha; Rajendran, Venugopal

    2012-11-01

    The kinetics of multi-site phase-transfer catalyzed free radical polymerisation of glycidyl methacrylate (GMA) using potassium peroxy disulphate (PDS) as water soluble initiator and newly synthesized 1,4-dihexadecylpyrazine-1,4-diium dibromide as multi-site phase-transfer catalyst (MPTC) has been investigated in ethyl acetate/water two phase system at constant temperature 65±1°C under nitrogen atmosphere and ultrasound irradiation conditions. The rate of polymerization increases with an increase in concentrations of GMA, PDS and MPTC. The order with respect to monomer, initiator and MPTC were found to be 1.0, 0.5 and 1.0, respectively. The comparative study reveals that the Rp of GMA determined in the presence of PTC combined with ultrasound has shown more enhancements in the activity than PTC alone. Based on the observed results a suitable mechanism has been proposed to account for the experimental observations and its significance was discussed.

  16. Polystyrene-supported Phenol/DMAP: an Efficient Binary Catalyst System for CO2 Fixation to Give Cyclic Carbonates

    Institute of Scientific and Technical Information of China (English)

    QI, Chao-Rong; JIANG, Huan-Feng; WANG, Zhao-Yang; ZOU, Bo

    2007-01-01

    Polystyrene-supported phenol (PS-PhOH) was successfully synthesized by alkylation reaction of phenol with 2% DVB cross-linked chloromethylated polystyrene and characterized by IR spectra and elemental analysis. In conjunction with an organic base such as DMAP, DBU, triethylamine (Et3N), diethylamine (Et2NH) or pyridine, the PS-PhOH could effectively catalyze the coupling reaction of carbon dioxide with epoxides to give cyclic carbonates in high yield and selectivity under mild conditions. The binary catalyst system of the PS-PhOH/DMAP was found to be the most active. The influence of reaction temperature, carbon dioxide pressure and reaction time on the yield of product was carefully investigated. The PS-PhOH could be recycled by simple filtration for at least up to ten times without loss of catalytic activity.

  17. Heterogeneous Catalysts

    NARCIS (Netherlands)

    Dakka, J.; Sheldon, R.A.; Sanderson, W.A.

    1997-01-01

    Abstract of GB 2309655 (A) Heterogeneous catalysts comprising one or more metal compounds selected from the group consisting of tin, molybdenum, tungsten, zirconium and selenium compounds deposited on the surface of a silicalite are provided. Preferably Sn(IV) and/or Mo(VI) are employed. The cat

  18. Heterogeneous chromium catalysts

    NARCIS (Netherlands)

    2005-01-01

    The present invention relates to a heterogeneous chromium catalyst system for the polymerisation of ethylene and/or alpha olefins prepared by the steps of: (a) providing a silica-containing support, (b) treating the silica-containing support with a chromium compound to form a chromium-based silica-c

  19. deNOx catalysts for biomass combustion

    DEFF Research Database (Denmark)

    Kristensen, Steffen Buus

    industrial reference catalyst, after impregnation of 225 mole potassium/g of catalyst. A catalyst plate was synthesised using 20 wt.% sepiolite mixed with nano catalyst, supported by a SiO2-fibre mesh. Realistic potassium poisoning was performed on the catalyst plate, by exposure in a potassium aerosol...... for 632 hours at 350 C. Owing to physical blocking of potassium by sepiolite fibres the composite catalyst showed a further increase in potassium resistance compared with the unsupported catalyst. Finally a refined mechanism was proposed for the nano particle SCR catalyst explaining insitu FTIR...... observation done on the system. Most importantly it indicated that the V=O bond did not break during the SCR reaction, suggesting that another oxygen is responsible for the activity of the active vanadia site....

  20. Surface chemistry and catalytic properties of VO{sub X}/Ti-MCM-41 catalysts for dibenzothiophene oxidation in a biphasic system

    Energy Technology Data Exchange (ETDEWEB)

    González, J. [ESIQIE, Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional s/n, 07738 Col. Zacatenco, Mexico City (Mexico); Chen, L.F., E-mail: lchen@ipn.mx [ESIQIE, Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional s/n, 07738 Col. Zacatenco, Mexico City (Mexico); Wang, J.A.; Manríquez, Ma.; Limas, R. [ESIQIE, Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional s/n, 07738 Col. Zacatenco, Mexico City (Mexico); Schachat, P.; Navarrete, J. [Dirección de Investigación, Instituto Mexicano del Petróleo, Eje Lázaro Cárdenas 152, 07730 México D.F. (Mexico); Contreras, J.L. [Laboratorio de Catálisis y Polímeros, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-A, Av. San Pablo No. 180, 02200 México D.F. (Mexico)

    2016-08-30

    Highlights: • Oxidative desulfurization of model diesel was tested in a biphasic system. • ODS activity was proportional to the V{sup 5+}/(V{sup 4+} + V{sup 5+}) values of the catalysts. • Lewis acidity was related to vanadium content and catalytic activity. • 99.9% DBT was oxidized using 25%V{sub 2}O{sub 5}/Ti-MCM-41 at 60 °C within 60 min. - Abstract: A series of vanadium oxide supported on Ti-MCM-41 catalysts was synthesized via the incipient impregnation method by varying the vanadia loading from 5 wt% to 10, 15, 20 and 25 wt%. These catalysts were characterized by a variety of advanced techniques for investigating their crystalline structure, textural properties, and surface chemistry information including surface acidity, reducibility, vanadium oxidation states, and morphological features. The catalytic activities of the catalysts were evaluated in a biphasic reaction system for oxidative desulfurization (ODS) of a model diesel containing 300 ppm of dibenzothiophene (DBT) where acetonitrile was used as extraction solvent and H{sub 2}O{sub 2} as oxidant. ODS activity was found to be proportional to the V{sup 5+}/(V{sup 4+} + V{sup 5+}) values of the catalysts, indicating that the surface vanadium pentoxide (V{sub 2}O{sub 5}) was the active phase. Reaction temperature would influence significantly the ODS efficiency; high temperature, i.e., 80 °C, would lead to low ODS reaction due to the partial decomposition of oxidant. All the catalysts contained both Lewis and Brønsted acid sites but the former was predominant. The catalysts with low vanadia loading (5 or 10 wt%V{sub 2}O{sub 5}) had many Lewis acid sites and could strongly adsorb DBT molecule via the electron donation/acceptance action which resulted in an inhibition for the reaction of DBT with the surface peroxometallic species. The catalyst with high vanadia loading (25wt%V{sub 2}O{sub 5}/Ti-MCM-41) showed the highest catalytic activity and could remove 99.9% of DBT at 60 °C within 60 min.

  1. A semiconductor gas sensor system for high throughput screening of heterogeneous catalysts for the production of benzene derivatives

    Science.gov (United States)

    Yamada, Yusuke; Ueda, Atsushi; Shioyama, Hiroshi; Maekawa, Toru; Kanda, Keisen; Suzuki, Kengo; Kobayashi, Tetsuhiko

    2005-01-01

    We used a semiconductor gas sensor system developed for odour discrimination for a rapid quantification of benzene derivatives which can be formed as the product of a catalytic reaction. Phenol can be obtained by the selective oxidation of benzene. The sensor system shows higher sensitivity to phenol than benzene. In particular, a SnO2 sensor sensitized with ZrO2 responds selectively to phenol. Aniline is provided as a reaction product between ammonia and benzene. The output signal of the gas sensor system increases when it is exposed to air containing aniline at the ppm level; on the other hand, the sensor output resulting from 1% ammonia in air does not increase so much. Cumene formation can be observed by the reaction of propane and benzene. The sensitivity of a SnO2 sensor sensitized with 12%SiO2-Al2O3 to cumene was about ten times higher than that to benzene. These results indicate that the semiconductor gas sensor system is useful for rapid screening of the catalyst for benzene functionalization.

  2. Efficient Nd Promoted Rh Catalysts for Vapor Phase Methanol Carbonylation

    Institute of Scientific and Technical Information of China (English)

    Shu Feng ZHANG; Qing Li QIAN; Ping Lai PAN; Yi CHEN; Guo Qing YUAN

    2005-01-01

    A Nd promoted-Rh catalysts supported on polymer-derived carbon beads for vapor-phase methanol carbonylation was developed. Rh-Nd bimetallic catalysts obviously have higher activity than that of supported Rh catalyst under similar reaction condition. The difference between the activity of above two catalyst systems is clearly caused by the intrinsic properties generated by the introduction of Nd.

  3. Synthesis of dimethyl ether and alternative fuels in the liquid phase from coal-derived synthesis gas. Task 3.2: Screen novel catalyst systems; Task 3.3:, Evaluation of the preferred catalyst system

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, R.P.

    1993-01-01

    As part of the DOE-sponsored contract ``Synthesis of Dimethyl Ether and Alternative Fuels in the Liquid Phase from Coal-Derived Syngas`` experimental evaluations of the one-step synthesis of alternative fuels were carried out. The objective of this work was to develop novel processes for converting coal-derived syngas to fuels or fuel additives. Building on a technology base acquired during the development of the Liquid Phase Methanol (LPMEOH) process, this work focused on the development of slurry reactor based processes. The experimental investigations, which involved bench-scale reactor studies, focused primarily on three areas: (1) One-step, slurry-phase syngas conversion to hydrocarbons or methanol/hydrocarbon mixtures using a mixture of methanol synthesis catalyst and methanol conversion catalyst in the same slurry reactor. (2) Slurry-phase conversion of syngas to mixed alcohols using various catalysts. (3) One-step, slurry-phase syngas conversion to mixed ethers using a mixture of mixed alcohols synthesis catalyst and dehydration catalyst in the same slurry reactor. The experimental results indicate that, of the three types of processes investigated, slurry phase conversion of syngas to mixed alcohols shows the most promise for further process development. Evaluations of various mixed alcohols catalysts show that a cesium-promoted Cu/ZnO/Al{sub 2}O{sub 3} methanol synthesis catalyst, developed in Air Products` laboratories, has the highest performance in terms of rate and selectivity for C{sub 2+}-alcohols. In fact, once-through conversion at industrially practical reaction conditions yielded a mixed alcohols product potentially suitable for direct gasoline blending. Moreover, an additional attractive aspect of this catalyst is its high selectivity for branched alcohols, potential precursors to iso-olefins for use in etherification.

  4. Structural and functional investigations of biological catalysts for optimization of solar-driven H II production systems

    Science.gov (United States)

    King, Paul W.; Svedruzic, Drazenka; Cohen, Jordi; Schulten, Klaus; Seibert, Michael; Ghirardi, Maria L.

    2006-08-01

    Research efforts to develop efficient systems for H II production encompass a variety of biological and chemical approaches. For solar-driven H II production we are investigating an approach that integrates biological catalysts, the [FeFe] hydrogenases, with a photoelectrochemical cell as a novel bio-hybrid system. Structurally the [FeFe] hydrogenases consist of an iron-sulfur catalytic site that in some instances is electronically wired to accessory iron-sulfur clusters proposed to function in electron transfer. The inherent structural complexity of most examples of these enzymes is compensated by characteristics desired for bio-hybrid systems (i.e., low activation energy, high catalytic activity and solubility) with the benefit of utilizing abundant, less costly non-precious metals. Redesign and modification of [FeFe] hydrogenases is being undertaken to reduce complexity and to optimize structural properties for various integration strategies. The least complex examples of [FeFe] hydrogenase are found in the species of photosynthetic green algae and are being studied as design models for investigating the effects of structural minimization on substrate transfer, catalytic activity and oxygen sensitivity. Redesigning hydrogenases for effective use in bio-hybrid systems requires a detailed understanding of the relationship between structure and catalysis. To achieve better mechanistic understanding of [FeFe] hydrogenases both structural and dynamic models are being used to identify potential substrate transfer mechanisms which are tested in an experimental system. Here we report on recent progress of our investigations in the areas of [FeFe] hydrogenase overexpression, minimization and biochemical characterization.

  5. In-line localized monitoring of catalyst activity in selective catalytic NO.sub.x reduction systems

    Science.gov (United States)

    Muzio, Lawrence J.; Smith, Randall A.

    2009-12-22

    Localized catalyst activity in an SCR unit for controlling emissions from a boiler, power plant, or any facility that generates NO.sub.x-containing flue gases is monitored by one or more modules that operate on-line without disrupting the normal operation of the facility. Each module is positioned over a designated lateral area of one of the catalyst beds in the SCR unit, and supplies ammonia, urea, or other suitable reductant to the catalyst in the designated area at a rate that produces an excess of the reductant over NO.sub.x on a molar basis through the designated area. Sampling probes upstream and downstream of the designated area draw samples of the gas stream for NO.sub.x analysis, and the catalyst activity is determined from the difference in NO.sub.x levels between the two probes.

  6. Low-temperature catalytic oxidative coupling of methane in an electric field over a Ce–W–O catalyst system

    OpenAIRE

    Kei Sugiura; Shuhei Ogo; Kousei Iwasaki; Tomohiro Yabe; Yasushi Sekine

    2016-01-01

    We examined oxidative coupling of methane (OCM) over various Ce–W–O catalysts at 423 K in an electric field. Ce2(WO4)3/CeO2 catalyst showed high OCM activity. In a periodic operation test over Ce2(WO4)3/CeO2 catalyst, C2 selectivity exceeded 60% during three redox cycles. However, Ce2(WO4)3/CeO2 catalyst without the electric field showed low activity, even at 1073 K: CH4 Conv., 6.0%; C2 Sel., 2.1%. A synergetic effect between the Ce2(WO4)3 structure and electric field created the reactive oxy...

  7. Catalyst Architecture

    DEFF Research Database (Denmark)

    Kiib, Hans; Marling, Gitte; Hansen, Peter Mandal

    2014-01-01

    of programs, have a role in mediating positive social and/or cultural development. In this sense, we talk about architecture as a catalyst for: sustainable adaptation of the city’s infrastructure appropriate renovation of dilapidated urban districts strengthening of social cohesiveness in the city development...... meaningful for everyone. The exhibited works are designed by SANAA, Diller Scofidio + Renfro, James Corner Field Operation, JBMC Arquitetura e Urbanismo, Atelier Bow-Wow, Ateliers Jean Nouvel, COBE, Transform, BIG, Topotek1, Superflex, and by visual artist Jane Maria Petersen....

  8. Development and Commercial Application of Third Generation Resid Hydrotreating Catalysts

    Institute of Scientific and Technical Information of China (English)

    Hu Dawei; Yang Qinghe; Dai Lishun; Zhao Xinqiang

    2013-01-01

    Based on the mechanism of resid hydrotreating reaction by coordinating the catalyst activity and stability, the diffusion mechanism and catalyst reactivity, the cost and catalyst performance, and the production and application re-quirements, the third-generation series catalysts for residue hydrotreating have been developed by Research Institute of Petroleum Processing, SINOPEC. The new series RHT catalysts possess higher activity for HDS, HDM and HDCCR per-formance as well as longer run length. The commercial results for application of these catalysts have demonstrated that the new catalyst system performs better than the reference ones.

  9. Autothermal reforming catalyst having perovskite structure

    Science.gov (United States)

    Krumpel, Michael; Liu, Di-Jia

    2009-03-24

    The invention addressed two critical issues in fuel processing for fuel cell application, i.e. catalyst cost and operating stability. The existing state-of-the-art fuel reforming catalyst uses Rh and platinum supported over refractory oxide which add significant cost to the fuel cell system. Supported metals agglomerate under elevated temperature during reforming and decrease the catalyst activity. The catalyst is a perovskite oxide or a Ruddlesden-Popper type oxide containing rare-earth elements, catalytically active firs row transition metal elements, and stabilizing elements, such that the catalyst is a single phase in high temperature oxidizing conditions and maintains a primarily perovskite or Ruddlesden-Popper structure under high temperature reducing conditions. The catalyst can also contain alkaline earth dopants, which enhance the catalytic activity of the catalyst, but do not compromise the stability of the perovskite structure.

  10. Cationic ruthenium alkylidene catalysts bearing phosphine ligands.

    Science.gov (United States)

    Endo, Koji; Grubbs, Robert H

    2016-02-28

    The discovery of highly active catalysts and the success of ionic liquid immobilized systems have accelerated attention to a new class of cationic metathesis catalysts. We herein report the facile syntheses of cationic ruthenium catalysts bearing bulky phosphine ligands. Simple ligand exchange using silver(i) salts of non-coordinating or weakly coordinating anions provided either PPh3 or chelating Ph2P(CH2)nPPh2 (n = 2 or 3) ligated cationic catalysts. The structures of these newly reported catalysts feature unique geometries caused by ligation of the bulky phosphine ligands. Their activities and selectivities in standard metathesis reactions were also investigated. These cationic ruthenium alkylidene catalysts reported here showed moderate activity and very similar stereoselectivity when compared to the second generation ruthenium dichloride catalyst in ring-closing metathesis, cross metathesis, and ring-opening metathesis polymerization assays.

  11. Development of a condenser for the dual catalyst water recovery system

    Science.gov (United States)

    Budinikas, P.; Rasouli, F.; Rabadi, N.

    1983-01-01

    Conceptual evaporation/condensation systems suitable for integration with the catalytic water recovery method were evaluated. The primary requirements for each concept were its capability to operate under zero-gravity conditions, condense recovered water from a vapor-noncondensable gas mixture, and integrate with the catalytic system. Specific energy requirements were estimated for concepts meeting the primary requirements, and the concept most suitable for integration with the catalytic system was proposed. A three-man rate condenser capable of integration with the proposed system, condensing water vapor in presence of noncondensables and transferring the heat of condensation to feed urine was designed, fabricated, and tested. It was treated with steam/air mixtures at atmospheric and elevated pressures and integrated with an actual catalytic water recovery system. The condenser has a condensation efficiency exceeding 90% and heat transfer rate of approximately 85% of theoretical value at coolant temperature ranging from 7 to 80 deg C.

  12. Automotive Catalyst State Diagnosis Using Microwaves

    Directory of Open Access Journals (Sweden)

    Moos Ralf

    2015-01-01

    Full Text Available The state of catalysts plays a key role in automotive exhaust gas aftertreatment. The soot or ash loading of Diesel particulate filters, the oxygen loading degree in three-way catalysts, the amount of stored ammonia in SCR catalysts, or the NOx loading degree in NOx storage catalysts are important parameters that are today determined indirectly and in a model-based manner with gas sensors installed upstream and/or downstream of the catalysts. This contribution gives an overview on a novel approach to determine the catalyst state directly by a microwave-based technique. The method exploits the fact that the catalyst housing acts as a microwave cavity resonator. As “sensing” elements, one or two simple antennas are mounted inside the catalyst canning. The electrical properties of the catalyst device (ceramic honeycomb plus coating and storage material can be measured. Preferably, the resonance characteristics, e.g., the resonance frequencies, of selected cavity modes are observed. The information on the catalyst interior obtained in such a contactless manner is very well correlated with the catalyst state as will be demonstrated for different exhaust gas aftertreatment systems.

  13. STUDIES ON THE RING-OPENING POLYMERIZATION OF TETRAHYDROFURAN Ⅳ. COPOLYMERIZATION OF TETRAHYDROFURAN AND PROPYLENE OXIDE INITIATED BY FUMING SULFURIC ACID AND PERCHLORIC ACID CATALYST SYSTEM

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hongzhi; GAO Guozhen; WANG Yin; FENG Xinde(S. T. Voong)

    1983-01-01

    The yield of copolymerization of tetrahydrofuran and propylene oxide (THF: PO = 100: 5-15, by wt) using a binary catalyst of fuming sulfuric acid (21% or 28%) and perchloric acid is around 50-60%, and the loss of THF in the reaction is below 10-15%. The average molecular weight of the product can be controlled in the range of 1000-2000 by varying the binary catalyst system.The present method, which is different from the usual copolymerization initiated by BF3-diol or SbCl5-diol system, shows the pecularities i.e. the yield of copolymerization with the low PO feed is not decreased, the hydroxyl functionality is equal to 2, and the end-groups are predominantly primary hydroxyls (around 65-70%).

  14. Surface analysis of model systems: From a metal-graphite interface to an intermetallic catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kwolek, Emma J. [Iowa State Univ., Ames, IA (United States)

    2016-10-25

    This thesis summarizes research completed on two different model systems. In the first system, we investigate the deposition of the elemental metal dysprosium on highly-oriented pyrolytic graphite (HOPG) and its resulting nucleation and growth. The goal of this research is to better understand the metal-carbon interactions that occur on HOPG and to apply those to an array of other carbon surfaces. This insight may prove beneficial to developing and using new materials for electronic applications, magnetic applications and catalysis.

  15. Simple systematization of vibrational excitation cross-section calculations for resonant electron-molecule scattering in the boomerang and impulse models.

    Science.gov (United States)

    Sarma, Manabendra; Adhikari, S; Mishra, Manoj K

    2007-01-28

    Vibrational excitation (nu(f), where psi(nu(i))(R,t) approximately =e(-iH(A(2))-(R)t/h phi(nu(i))(R) with time evolution under the influence of the resonance anionic Hamiltonian H(A(2) (-))(A(2) (-)=N(2)(-)/H(2) (-)) implemented using Lanczos and fast Fourier transforms. The target (A(2)) vibrational eigenfunctions phi(nu(i))(R) and phi(nu(f))(R) are calculated using Fourier grid Hamiltonian method applied to potential energy (PE) curves of the neutral target. Application of this simple systematization to calculate vibrational structure in e-N(2) and e-H(2) scattering cross-sections provides mechanistic insights into features underlying presence/absence of structure in e-N(2) and e-H(2) scattering cross-sections. The results obtained with approximate PE curves are in reasonable agreement with experimental/calculated cross-section profiles, and cross correlation functions provide a simple demarcation between the boomerang and impulse models.

  16. CMB Analysis of Boomerang & Maxima & the Cosmic Parameters {Omega_tot,Omega_b h^2,Omega_cdm h^2,Omega_Lambda,n_s}

    CERN Document Server

    Bond, J R; Balbi, A; Bock, J J; Borrill, J; Boscaleri, A; Coble, K; Crill, B P; De Bernardis, P; Farese, P; Ferreira, P; Ganga, K; Giacometti, M; Hanany, S; Hivon, E; Hristov, V V; Iacoangeli, A; Jaffe, A; Lange, A; Lee, A; Martinis, L; Masi, S; Mauskopf, P D; Melchiorri, A; Montroy, T; Netterfield, C B; Oh, S; Pascale, E; Piacentini, F; Pogosyan, D; Prunet, S; Rabii, B; Rao, S; Richards, P; Romeo, G; Ruhl, J E; Scaramuzzi, F; Sforza, D M; Sigurdson, K; Smoot, G F; Stompor, R; Winant, C; Wu, P

    2000-01-01

    We show how estimates of parameters characterizing inflation-based theories of structure formation localized over the past year when large scale structure (LSS) information from galaxy and cluster surveys was combined with the rapidly developing cosmic microwave background (CMB) data, especially from the recent Boomerang and Maxima balloon experiments. All current CMB data plus a relatively weak prior probability on the Hubble constant, age and LSS points to little mean curvature (Omega_{tot} = 1.08\\pm 0.06) and nearly scale invariant initial fluctuations (n_s =1.03\\pm 0.08), both predictions of (non-baroque) inflation theory. We emphasize the role that degeneracy among parameters in the L_{pk} = 212\\pm 7 position of the (first acoustic) peak plays in defining the $\\Omega_{tot}$ range upon marginalization over other variables. Though the CDM density is in the expected range (\\Omega_{cdm}h^2=0.17\\pm 0.02), the baryon density Omega_bh^2=0.030\\pm 0.005 is somewhat above the independent 0.019\\pm 0.002 nucleosynth...

  17. A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide.

    Science.gov (United States)

    Ng, Chee Koon; Wu, Jie; Hor, T S Andy; Luo, He-Kuan

    2016-09-27

    Binary catalyst systems comprising a cationic Ru-CNC pincer complex and an alkali metal salt were developed for selective hydroboration of CO2 utilizing pinacolborane at r.t. and 1 atm CO2, with the combination of [Ru(CNCBn)(CO)2(H)][PF6] and KOCO2(t)Bu producing formoxyborane in 76% yield. A bicyclic catalytic mechanism was proposed and discussed.

  18. CrCl3·6H2O/Hydrogenated Bis-Schiff Base as a New Efficient Catalyst System for Synthesis of Bis(indoly) Methane%CrCl3·6H2O/Hydrogenated Bis-Schiff Base as a New Efficient Catalyst System for Synthesis of Bis(indoly) Methane

    Institute of Scientific and Technical Information of China (English)

    杨永磊; 解正峰; 王吉德

    2011-01-01

    CrCl3·6H2O/hydrogenated bis-Schiff base is found to be an effective catalyst system for synthesis of bis(indoly) methane via electrophilic addition reaction of indoles with aldehydes using acetonitrile as the solvent. The yields of isolated products are from good to excellent.

  19. Integrated System in the Malaysian Education Paradigm: A Catalyst for a Holistic Personality Development

    Science.gov (United States)

    Othman, Nooraini; Mohamad, Khairul Azmi

    2014-01-01

    This paper intends to describe and analyse the process of education reform that has taken place in Malaysia. Islamisation plays a major role in such reform. The approach is innovative and novel in nature. Historically, Malaysia was under the British colony and the British left a strong impact in the education system. Naturally the position of…

  20. Catalyst Architecture

    DEFF Research Database (Denmark)

    the projects as case studies, which contribute with strategic knowledge rather than generalizing from average considerations. These are ‘strategic projects’ where we have looked for the specific and the particular (Flyvbjerg 1991). According to the case studies, we use the case study method developed by Bent......’ interpretations and architectural strategies are included in the analyses. This implies that there is a large variation of empirical knowledge about the selected problems. That is the reason why we give a short introduction to the exact use of approaches and methods in the beginning of each case study. Based...... in experience? Which design qualities do the best examples of architecture as urban catalysts have, and how can we as citizens, politicians and professionals use knowledge about this in the development of our cities as good places to live? We wish to throw light on these key questions through case studies...

  1. Facile heterogenization of a cobalt catalyst via graphene adsorption: robust and versatile dihydrogen production systems.

    Science.gov (United States)

    Eady, Shawn C; Peczonczyk, Sabrina L; Maldonado, Stephen; Lehnert, Nicolai

    2014-07-28

    A heterogeneous dihydrogen (H2) production system has been attained by simply soaking electrodes made from electro-deposited graphene on FTO plated glass in solutions of a cobalt bis(dithiolate) compound. The resulting electrodes are active in weakly acidic aqueous solutions (pH > 3), have relatively low overpotentials (0.37 V versus platinum), show high catalytic rates (TOF > 1000 s(-1)), and are resistant to degradation by dioxygen.

  2. Can main group systems act as superior catalysts for dihydrogen generation reactions? A computational investigation.

    Science.gov (United States)

    Kuriakose, Nishamol; Vanka, Kumar

    2016-04-14

    The protolytic cleavage of the O-H bond in water and alcohols is a very important reaction, and an important method for producing dihydrogen. Full quantum chemical studies with density functional theory (DFT) reveal that germanium based complexes, such as HC{CMeArB}2GeH (Ar = 2,6-(i)Pr2C6H3), with the assistance of silicon based compounds such as SiF3H, can perform significantly better than the existing state-of-the-art post-transition metal based systems for catalyzing dihydrogen generation from water and alcohols through the protolysis reaction.

  3. Condensation reaction of formaldehyde and methyl formate catalyzed by a composite catalyst system

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The condensation reaction of formaldehyde and methyl formate to form methyl glycolate and methyl methoxy acetate catalyzed by p-toluenesulfonic acid and different Lewis acid compounds has been investigated. The composite catalytic system consisting of p-toluenesulfonic acid and NiX2 (X = Cl, Br, I), especially NiI2, exhibited a high catalytic performance for the condensation reaction, the total yield of MG and MMAc was up to 72.37%.(C) 2007 Gong Ying Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  4. Method of treating emissions of a hybrid vehicle with a hydrocarbon absorber and a catalyst bypass system

    Science.gov (United States)

    Roos, Bryan Nathaniel; Gonze, Eugene V; Santoso, Halim G; Spohn, Brian L

    2014-01-14

    A method of treating emissions from an internal combustion engine of a hybrid vehicle includes directing a flow of air created by the internal combustion engine when the internal combustion engine is spinning but not being fueled through a hydrocarbon absorber to collect hydrocarbons within the flow of air. When the hydrocarbon absorber is full and unable to collect additional hydrocarbons, the flow of air is directed through an electrically heated catalyst to treat the flow of air and remove the hydrocarbons. When the hydrocarbon absorber is not full and able to collect additional hydrocarbons, the flow of air is directed through a bypass path that bypasses the electrically heated catalyst to conserve the thermal energy stored within the electrically heated catalyst.

  5. Niobium(v) chloride and imidazolium bromides as efficient dual catalyst systems for the cycloaddition of carbon dioxide and propylene oxide

    KAUST Repository

    Wilhelm, Michael E.

    2014-02-19

    The application of niobium(v) chloride and several imidazolium bromides as catalyst systems for the cycloaddition of propylene oxide (PO) with carbon dioxide to propylene carbonate (PC) is reported. A set of 31 different imidazolium bromides has been synthesized with varying substituents at all five imidazolium ring atoms, of which 17 have not been reported before. The impact of different substitution patterns (steric and electronic changes and solubility in PO) at the imidazolium ring on the catalytic activity was investigated. The optimisation of the catalyst structure allows for the valorisation of carbon dioxide under mild reaction conditions with high reaction rates in very good yield and selectivity for PC. This journal is © the Partner Organisations 2014.

  6. Niobium(v) chloride and imidazolium bromides as efficient dual catalyst systems for the cycloaddition of carbon dioxide and propylene oxide

    KAUST Repository

    Wilhelm, Michael E.

    2014-01-01

    The application of niobium(v) chloride and several imidazolium bromides as catalyst systems for the cycloaddition of propylene oxide (PO) with carbon dioxide to propylene carbonate (PC) is reported. A set of 31 different imidazolium bromides has been synthesized with varying substituents at all five imidazolium ring atoms, of which 17 have not been reported before. The impact of different substitution patterns (steric and electronic changes and solubility in PO) at the imidazolium ring on the catalytic activity was investigated. The optimisation of the catalyst structure allows for the valorisation of carbon dioxide under mild reaction conditions with high reaction rates in very good yield and selectivity for PC. This journal is © the Partner Organisations 2014.

  7. Characterisation of a PdCl 2/SnCl 2 electroless plating catalyst system adsorbed on barium titanate-based electroactive ceramics

    Science.gov (United States)

    Meenan, B. J.; Brown, N. M. D.; Wilson, J. W.

    1994-03-01

    A PdCl 2/SnCl 2 metallisation catalyst system, of the type used to activate non-conducting surfaces for electroless metal deposition, has been characterised by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The substrate is a barium titanate (BaTiO 3)-based electroactive ceramic of the type used in the fabrication of multilayer ceramic capacitors (MLCC). The treatment of the substrate surface with the PdCl 2/SnCl 2 "sensitiser" solution leads to the adsorption of catalytically inactive compounds of palladium and tin. Subsequent treatment of this surface with an "accelerator" solution removes excess oxides, hydroxides and salts of tin thereby leaving the active catalyst species, Pd xSn y, on the surface. Such sites, on exposure to the appropriete electroless plating bath, are then responsible for the metal deposition. In this study, the chemical state and relative quantities of the various surface species present after each of the processing stages have been determined by XPS. The surface roughness of the substrate results in less of the tin compounds present thereon being removed on washing the catalysed surface in the accelerator solution than normally reported for such systems, thereby affecting the measured Pd: Sn ratio. SEM studies show that the accelerator solution treatment generates crystalline areas, which may be a result of coagulation of the Pd xSn y particles present, in the otherwise amorphous catalyst coating.

  8. Wet air oxidation of pretreatment of pharmaceutical wastewater by Cu2+ and [PxWmOy]q- co-catalyst system.

    Science.gov (United States)

    Wang, Guowen; Wang, Dong; Xu, Xiaochen; Liu, Lifen; Yang, Fenglin

    2012-05-30

    This study concentrates on the pretreatment of real wastewater using catalytic wet air oxidation (CWAO). WO(3-) and PO(4)(3-) contained in fosfomycin pharmaceutical wastewater (FPW) and Cu(2+) contained in berberine pharmaceutical wastewater (BPW) were studied as CWAO influent. Mixture of this two streams were reused to form Cu(2+) and [P(x)W(m)O(y)](q-), namely polyoxometalates (POMs) as co-catalyst system to treat themselves. Experiments were conducted to investigate the effects of the initial oxygen pressure and temperature on the COD (chemical oxygen demand), TOC (total organic carbon) removal and biodegradable enhancement, it was discovered that over 40% of COD and TOC removal can be easily realized in an hour of WAO oxidation at 523 K, 1.4 MPa. The BOD(5)/COD (BOD(5), biochemical oxygen demand in 5 days) of this two pharmaceutical mixture ascended from nonexistent to maximum 0.41 depends on the optimal FPW:BPW volume ratio 4:1, to compose POM co-catalyst system. Organic pollutants were incompletely oxidized to propionic acid and other intermediates. Some properties (e.g., TGA, IR, XRF) of POM catalyst separated from effluent, were obtained to provide additional information.

  9. Africa's game changers and the catalysts of social and system innovation

    Directory of Open Access Journals (Sweden)

    Mark Swilling

    2016-03-01

    Full Text Available It is widely recognized that many African economies are being transformed by rapid economic growth driven largely by rising demand for the abundant natural resources scattered across the African continent. I critically review the mainstream game-changing dynamics driving this process, with special reference to a set of influential policy-oriented documents. This is followed by an analysis of less-recognized game-changing dynamics that have, in turn, been affected by the mainstream game-changing dynamics. These less-recognized game-changing dynamics include energy infrastructure challenges in a context of climate change, securing access to water, access to arable soils, slum urbanism, and food security responses. These mainstream and less-recognized game-changing dynamics provide the context for analyzing a range of African actor networks engaged in social and system innovations. I use a transdisciplinary framework to discuss these actor networks and how they construct their understanding of the game changers affecting their programs and actions. Based on a case study of the iShack initiative in Stellenbosch, South Africa, I conclude that social and system innovations will need to be driven by transformation knowledge co-produced by researchers and social actors who can actively link game-changing dynamics that operate at multiple scales with local-level innovations with potential societal impacts.

  10. Electrochemical catalyst recovery method

    Science.gov (United States)

    Silva, Laura J.; Bray, Lane A.

    1995-01-01

    A method of recovering catalyst material from latent catalyst material solids includes: a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications.

  11. 2D-QSPR/DFT studies of aryl-substituted PNP-Cr-based catalyst systems for highly selective ethylene oligomerization.

    Science.gov (United States)

    Tang, Siyang; Liu, Zhen; Zhan, Xingwen; Cheng, Ruihua; He, Xuelian; Liu, Boping

    2014-03-01

    1-Hexene and 1-octene are important comonomers for the synthesis of high performance polyolefins. Recently, various N-substituted Cr-bis(diphenylphosphino)amine (PNP-Cr) catalysts show the potential as excellent candidates for highly selective ethylene trimerization/tetramerization. In this work, a series of aryl-substituted PNP-Cr catalysts were studied by two-dimensional quantitative structure-property relationship (QSPR) method based on density functional theory (DFT) calculations. The heuristic method (HM) and best multi-linear regression (BMLR) were used to establish the best linear regression models to describe the relationship between selectivities and catalyst structures. Both Cr(I) and Cr(II) active site models for ethylene trimerization/tetramerization were considered. It was found that 1) the relativity and stability of the models were increased by using self-defined descriptors based on DFT calculations; 2) Cr(I)/Cr(III) centers were the most plausible active sites for ethylene trimerization, while Cr(II)/Cr(IV) active sites were most possibly responsible for ethylene tetramerization; and 3) the skeleton structures of the PNP-Cr system with good complanation and symmetry were crucial for achieving excellent catalytic selectivity of 1-octene, while the PNP-Cr backbone with a large steric effect on N atom would benefit ethylene trimerization. Six new PNP ligands with high selectivity toward ethylene trimerization/tetramerization were predicted based on descriptor analysis and the best linear regression models providing a good basis for further development of novel catalyst systems with better performance.

  12. Efficiency and mechanism of degradation of alachlor in water by O3/H2O2 catalyst system

    Institute of Scientific and Technical Information of China (English)

    高金胜; 于颖慧; 孙志忠; 马军

    2003-01-01

    Alachlor is used widely as a herbicide,but is an environmental endocrine disruptor. O3/H2O2 systemis used as catalyst to delve on the degradation efficiency of alachlor. The amount of the catalyst-H2O2 ,the pHvalue of the soluble, the temperature and quality of water sample are changed to investigate the effect of thesefactors on the degradation of alaehlor. The degradation of alachlor is qualitatively analyzed through their GS-MSspectra and the possible mechanism of the degradation of alachlor is discussed as well.

  13. Systems including catalysts in porous zeolite materials within a reactor for use in synthesizing hydrocarbons

    Science.gov (United States)

    Rolllins, Harry W [Idaho Falls, ID; Petkovic, Lucia M [Idaho Falls, ID; Ginosar, Daniel M [Idaho Falls, ID

    2012-07-24

    Catalytic structures include a catalytic material disposed within a zeolite material. The catalytic material may be capable of catalyzing a formation of methanol from carbon monoxide and/or carbon dioxide, and the zeolite material may be capable of catalyzing a formation of hydrocarbon molecules from methanol. The catalytic material may include copper and zinc oxide. The zeolite material may include a first plurality of pores substantially defined by a crystal structure of the zeolite material and a second plurality of pores dispersed throughout the zeolite material. Systems for synthesizing hydrocarbon molecules also include catalytic structures. Methods for synthesizing hydrocarbon molecules include contacting hydrogen and at least one of carbon monoxide and carbon dioxide with such catalytic structures. Catalytic structures are fabricated by forming a zeolite material at least partially around a template structure, removing the template structure, and introducing a catalytic material into the zeolite material.

  14. Ceria nanoclusters on graphene/Ru(0001): A new model catalyst system

    Science.gov (United States)

    Novotny, Z.; Netzer, F. P.; Dohnálek, Z.

    2016-10-01

    The growth of ceria nanoclusters on single-layer graphene on Ru(0001) has been examined, with a view towards fabricating a stable system for model catalysis studies. The surface morphology and cluster distribution as a function of oxide coverage and substrate temperature has been monitored by scanning tunneling microscopy (STM), whereas the chemical composition of the cluster deposits has been determined by Auger electron spectroscopy (AES). The ceria nanoparticles are of the CeO2(111)-type and are anchored at the intrinsic defects of the graphene surface, resulting in a variation of the cluster densities across the macroscopic sample surface. The ceria clusters on graphene display a remarkable stability against reduction in ultrahigh vacuum up to 900 K, but some sintering of clusters is observed for temperatures > 450 K. The evolution of the cluster size distribution suggests that the sintering proceeds via a Smoluchowski ripening mechanism, i.e. diffusion and aggregation of entire clusters.

  15. Rapid Syphilis Tests as Catalysts for Health Systems Strengthening: A Case Study from Peru

    Science.gov (United States)

    García, Patricia J.; Cárcamo, César P.; Chiappe, Marina; Valderrama, Maria; La Rosa, Sayda; Holmes, King K.; Mabey, David C. W.; Peeling, Rosanna W.

    2013-01-01

    Objectives Untreated maternal syphilis leads to adverse pregnancy outcomes. The use of point of care tests (POCT) offers an opportunity to improve screening coverage for syphilis and other aspects of health systems. Our objective is to present the experience of the introduction of POCT for syphilis in Peru and describe how new technology can catalyze health system strengthening. Methods The study was implemented from September 2009–November 2010 to assess the feasibility of the use of a POCT for syphilis for screening pregnant women in Lima, Peru. Outcomes measured included access to syphilis screening, treatment coverage, partner treatment, effect on patient flow and service efficiency, acceptability among providers and patients, and sustainability. Results Before the introduction of POCT, a pregnant woman needed 6 visits to the health center in 27 days before she received her syphilis result. We trained 604 health providers and implemented the POCT for syphilis as the “two for one strategy”, offering with one finger stick both syphilis and HIV testing. Implementation of the POCT resulted in testing and treatment on the first visit. Screening and treatment coverages for syphilis improved significantly compared with the previous year. Implementation of POCT has been scaled up nationally since the study ended, and coverages for screening, treatment and partner treatment have remained over 92%. Conclusions Implementation of POCT for syphilis proved feasible and acceptable, and led to improvement in several aspects of health services. For the process to be effective we highlight the importance of: (1) engaging the authorities; (2) dissipating tensions between providers and identifying champions; (3) training according to the needs; (4) providing monitoring, supervision, support and recognition; (5) sharing results and discussing actions together; (6) consulting and obtaining feedback from users; and (7) integrating with other services such as with rapid HIV

  16. Rapid Syphilis Tests as Catalysts for Health Systems Strengthening: A Case Study from Peru.

    Directory of Open Access Journals (Sweden)

    Patricia J García

    Full Text Available Untreated maternal syphilis leads to adverse pregnancy outcomes. The use of point of care tests (POCT offers an opportunity to improve screening coverage for syphilis and other aspects of health systems. Our objective is to present the experience of the introduction of POCT for syphilis in Peru and describe how new technology can catalyze health system strengthening.The study was implemented from September 2009-November 2010 to assess the feasibility of the use of a POCT for syphilis for screening pregnant women in Lima, Peru. Outcomes measured included access to syphilis screening, treatment coverage, partner treatment, effect on patient flow and service efficiency, acceptability among providers and patients, and sustainability.Before the introduction of POCT, a pregnant woman needed 6 visits to the health center in 27 days before she received her syphilis result. We trained 604 health providers and implemented the POCT for syphilis as the "two for one strategy", offering with one finger stick both syphilis and HIV testing. Implementation of the POCT resulted in testing and treatment on the first visit. Screening and treatment coverages for syphilis improved significantly compared with the previous year. Implementation of POCT has been scaled up nationally since the study ended, and coverages for screening, treatment and partner treatment have remained over 92%.Implementation of POCT for syphilis proved feasible and acceptable, and led to improvement in several aspects of health services. For the process to be effective we highlight the importance of: (1 engaging the authorities; (2 dissipating tensions between providers and identifying champions; (3 training according to the needs; (4 providing monitoring, supervision, support and recognition; (5 sharing results and discussing actions together; (6 consulting and obtaining feedback from users; and (7 integrating with other services such as with rapid HIV testing.

  17. Catalytic hydrodechlorination of trichloroethylene in a novel NaOH/2-propanol/methanol/water system on ceria-supported Pd and Rh catalysts.

    Science.gov (United States)

    Cobo, Martha; Becerra, Jorge; Castelblanco, Miguel; Cifuentes, Bernay; Conesa, Juan A

    2015-08-01

    The catalytic hydrodechlorination (HDC) of high concentrations of trichloroethylene (TCE) (4.9 mol%, 11.6 vol%) was studied over 1%Pd, 1%Rh and 0.5%Pd-0.5%Rh catalysts supported on CeO2 under conditions of room temperature and pressure. For this, a one-phase system of NaOH/2-propanol/methanol/water was designed with molar percentages of 13.2/17.5/36.9/27.6, respectively. In this system, the alcohols delivered the hydrogen required for the reaction through in-situ dehydrogenation reactions. PdRh/CeO2 was the most active catalyst for the degradation of TCE among the evaluated materials, degrading 85% of the trichloroethylene, with alcohol dehydrogenation rates of 89% for 2-propanol and 83% for methanol after 1 h of reaction. Fresh and used catalysts were characterized by Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Thermogravimetric analysis (TGA). These results showed important differences of the active phase in each catalyst sample. Rh/CeO2 had particle sizes smaller than 1 nm and the active metal was partially oxidized (Rh(0)/Rh(+δ) ratio of 0.43). This configuration showed to be suitable for alcohols dehydrogenation. On the contrary, Pd/CeO2 showed a Pd completed oxidized and with a mean particle size of 1.7 nm, which seemed to be unfavorable for both, alcohols dehydrogenation and TCE HDC. On PdRh/CeO2, active metals presented a mean particle size of 2.7 nm and more reduced metallic species, with ratios of Rh(0)/Rh(+δ) = 0.67 and Pd(0)/Pd(+δ) = 0.28, which showed to be suitable features for the TCE HDC. On the other hand, TGA results suggested some deposition of NaCl residues over the catalyst surfaces. Thus, the new reaction system using PdRh/CeO2 allowed for the degradation of high concentrations of the chlorinated compound by using in situ hydrogen liquid donors in a reaction at room temperature and pressure.

  18. Hydrogenation of fast pyrolyis oil and model compounds in a two-phase aqueous organic system using homogeneous ruthenium catalysts

    NARCIS (Netherlands)

    Mahfud, F. H.; Ghijsen, F.; Heeres, H. J.

    2007-01-01

    The use of homogeneous ruthenium catalysts to hydrogenate the water-soluble fraction of pyrolysis oil is reported. Pyrolysis oil, which is obtained by fast pyrolysis of lignocellulosic biomass at 450-600 degrees C, contains significant amounts of aldehydes and ketones (e.g. 1-hydroxy-2-propanone (1)

  19. Low-temperature catalytic oxidative coupling of methane in an electric field over a Ce–W–O catalyst system

    Science.gov (United States)

    Sugiura, Kei; Ogo, Shuhei; Iwasaki, Kousei; Yabe, Tomohiro; Sekine, Yasushi

    2016-04-01

    We examined oxidative coupling of methane (OCM) over various Ce–W–O catalysts at 423 K in an electric field. Ce2(WO4)3/CeO2 catalyst showed high OCM activity. In a periodic operation test over Ce2(WO4)3/CeO2 catalyst, C2 selectivity exceeded 60% during three redox cycles. However, Ce2(WO4)3/CeO2 catalyst without the electric field showed low activity, even at 1073 K: CH4 Conv., 6.0%; C2 Sel., 2.1%. A synergetic effect between the Ce2(WO4)3 structure and electric field created the reactive oxygen species for selective oxidation of methane. Results of XAFS, in-situ Raman and periodic operation tests demonstrated that OCM occurred as the lattice oxygen in Ce2(WO4)3 (short W–O bonds in distorted WO4 unit) was consumed. The consumed oxygen was reproduced by a redox mechanism in the electric field.

  20. Low-temperature catalytic oxidative coupling of methane in an electric field over a Ce-W-O catalyst system.

    Science.gov (United States)

    Sugiura, Kei; Ogo, Shuhei; Iwasaki, Kousei; Yabe, Tomohiro; Sekine, Yasushi

    2016-04-27

    We examined oxidative coupling of methane (OCM) over various Ce-W-O catalysts at 423 K in an electric field. Ce2(WO4)3/CeO2 catalyst showed high OCM activity. In a periodic operation test over Ce2(WO4)3/CeO2 catalyst, C2 selectivity exceeded 60% during three redox cycles. However, Ce2(WO4)3/CeO2 catalyst without the electric field showed low activity, even at 1073 K: CH4 Conv., 6.0%; C2 Sel., 2.1%. A synergetic effect between the Ce2(WO4)3 structure and electric field created the reactive oxygen species for selective oxidation of methane. Results of XAFS, in-situ Raman and periodic operation tests demonstrated that OCM occurred as the lattice oxygen in Ce2(WO4)3 (short W-O bonds in distorted WO4 unit) was consumed. The consumed oxygen was reproduced by a redox mechanism in the electric field.

  1. Palladium(II/Cationic 2,2’-Bipyridyl System as a Highly Efficient and Reusable Catalyst for the Mizoroki-Heck Reaction in Water

    Directory of Open Access Journals (Sweden)

    Fu-Yu Tsai

    2010-01-01

    Full Text Available A water-soluble and air-stable Pd(NH32Cl2/cationic 2,2’-bipyridyl system was found to be a highly-efficient and reusable catalyst for the coupling of aryl iodides and alkenes in neat water using Bu3N as a base. The reaction was conducted at 140 °C in a sealed tube in air with a catalyst loading as low as 0.0001 mol % for the coupling of activated aryl iodides with butyl and ethyl acrylates, providing the corresponding products in good to excellent yields with very high turnover numbers. In the case of styrene, Mizoroki-Heck coupling products were obtained in good to high yields by using a greater catalyst loading (1 mol % and TBAB as a phase-transfer agent. After extraction, the residual aqueous solution could be reused several times with only a slight decrease in its activity, making the Mizoroki-Heck reaction “greener”.

  2. Method for reactivating catalysts and a method for recycling supercritical fluids used to reactivate the catalysts

    Science.gov (United States)

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2008-08-05

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  3. Catalysts for decomposing ozone tail gas

    Institute of Scientific and Technical Information of China (English)

    LIU Chang-an; SUN De-zhi; WANG Hui; LI Wei

    2003-01-01

    The preparation of immobilizing-catalysts for decomposing ozone by using dipping method was studied. XRD, XPS and TEM were used to characterize the catalysts. The three kinds of catalysts were selected preferentially, and their catalytic activities were investigated. The results showed that the catalyst with activated carbon dipping acetate (active components are Mn: Cu = 3:2, active component proportion in catalyst is 15%, calcination temperature is 200℃ ) has the best catalytic activity for ozone decomposing. One gram of catalyst can decompose 17.6 g ozone at initial ozone concentration of 2.5 g/m3 and the residence time in reactor of 0.1 s. The experimental results also indicated that humidity of reaction system had negative effect on catalytic activity.

  4. A comparison study of toluene removal by two-stage DBD-catalyst systems loading with MnO(x), CeMnO(x), and CoMnO(x).

    Science.gov (United States)

    Huang, Yifan; Dai, Shaolong; Feng, Fada; Zhang, Xuming; Liu, Zhen; Yan, Keping

    2015-12-01

    This paper studies the toluene removal by a two-stage dielectric barrier discharge (DBD)-catalyst system with three catalysts: MnO(x)/ZSM-5, CoMnO(x)/ZSM-5, and CeMnO(x)/ZSM-5. V-Q Lissajous method, Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), and X-ray photoelectron (XPS) are used to characterize the DBD and catalysts. The DBD processing partially oxidizes the toluene, and the removal efficiency has a linear relationship with ozone generation. Three DBD-catalyst systems are compared in terms of their toluene removal efficiency, Fourier transform infrared (FTIR) spectra, carbon balance, CO selectivity, CO2 selectivity, and ozone residual. The results show that the DBD-catalyst system with CoMnO(x)/ZSM-5 performs better than the other two systems. It has the highest removal efficiency of about 93.7%, and the corresponding energy yield is 4.22 g/kWh. The carbon balance and CO2 selectivity of CoMnO(x)/ZSM-5 is also better than the other two catalysts. The measurements of two important byproducts including aerosols and ozone are also presented.

  5. Design and fabrication of an automated temperature programmed reaction system to evaluate 3-way catalysts Ce1--(La/Y)PtO2-

    Indian Academy of Sciences (India)

    Arup Gayen; Tinku Baidya; G S Ramesh; R Sriharia; M S Hegde

    2006-01-01

    A completely automated temperature-programmed reaction (TPR) system for carrying out gas-solid catalytic reactions under atmospheric flow conditions is fabricated to study CO and hydrocarbon oxidation, and NO reduction. The system consists of an all-stainless steel UHV system, quadrupole mass spectrometer SX200 (VG Scientific), a tubular furnace and micro-reactor, a temperature controller, a versatile gas handling system, and a data acquisition and analysis system. The performance of the system has been tested under standard experimental conditions for CO oxidation over well-characterized Ce1--Pt(La/Y)O2- catalysts. Testing of 3-way catalysis with CO, NO and C2H2 to convert to CO2, N2 and H2O is done with this catalyst which shows complete removal of pollutants below 325°C. Fixed oxide-ion defects in Pt substituted Ce1-(La/Y)O2-/2 show higher catalytic activity than Pt ion-substituted CeO2.

  6. From Homogeneous to Heterogenized Solar Fuels Assemblies: Observation of Electron Transfer Events in Systems Containing Dye-Sensitized Semiconductors and Molecular Catalysts

    Science.gov (United States)

    Kamire, Rebecca Joy

    The conversion of solar energy into chemical energy by simultaneously oxidizing water and reducing protons to hydrogen could provide a much-needed fuel source within a more sustainable energy economy. Dye-sensitized photoelectrochemical cells (DSPECs) are capable of forming fuels using sunlight if photoexcited chromophores transfer charges to semiconductor electrodes and catalysts, and catalysis occurs, at rates exceeding those of charge recombination. The rational design of efficient DSPECs will require an understanding of the catalytic mechanisms and rate-limiting steps of the oxidative and reductive reactions. Here, we focus on how molecular and electrode design can be used to favor the desired charge transfer events from photoexcited perylene-3,4-dicarboximide (PMI) chromophores into semiconductor films and to molecular catalysts. Previous efforts with related chromophores have focused on charge transfer between dyes and catalysts in homogeneous covalent systems without the presence of a supporting electrode. In this work, femtosecond to millisecond transient absorption spectroscopies are utilized to identify a PMI derivative capable of injecting electrons into nanostructured semiconductor films with favorable rates and yields. The identified derivative is further used to oxidize covalently attached homogeneous water oxidation catalyst (WOC) precursor Cp*Ir III(ppy)Cl, where ppy = 2-phenylpyridine, on TiO2 and then incorporated into several photoelectrodes for photodriven water oxidation and hydrogen production. Atomic layer deposition of Al2O3 following chromophore adsorption is employed to improve the chemical stability of the chromophores and to prevent rapid electron-hole recombination. The TiO2-based photoanodes contain a coadsorbed WOC [(Ir IV(pyalc)(H2O)R)2(micro-O)] +2, where pyalc = 2-(2'pyridyl)-2-propanolate, or its mononuclear precursor functionalized with a siloxane binding group. NiO-based photocathodes include molecular cobaloxime- or [Ni(P2N2) 2

  7. A micro-structured 5kW complete fuel processor for iso-octane as hydrogen supply system for mobile auxiliary power units Part I. Development of autothermal reforming catalyst and reactor

    OpenAIRE

    Kolb, Gunther; Baier, Tobias; Schürer, Jochen; Tiemann, David; Ziogas, Athanassios; Ehwald, Hermann; Alphonse, Pierre

    2008-01-01

    A micro-structured autothermal reformer was developed for a fuel processing/fuel cell system running on iso-octane and designed for an electrical power output of 5kWel. The target application was an automotive auxiliary power unit (APU). The work covered both catalyst and reactor development. In fixed bed screening, nickel and rhodium were identified as the best candidates for autothermal reforming of gasoline. Under higher feed flow rates applied in microchannel testing, a catalyst formul...

  8. Aldol condensations of a variety of different aldehydes and ketones under ultrasonic irradiation using poly(N-vinylimidazole) as a new heterogeneous base catalyst under solvent-free conditions in a liquid-solid system

    Institute of Scientific and Technical Information of China (English)

    Nader Ghaffari Khaligh; Taraneh Mihankhah

    2013-01-01

    An ultrasound-assisted aldol condensation reaction has been developed for a range of ketones with a variety of aromatic aldehydes using poly(N-vinylimidazole) as a solid base catalyst in a liquid-solid system. The catalyst can be recovered by simple filtration and reused at least 10 times without any significant reduction in its activity. The reaction is also amenable to the large scale, making the pro-cedure potentially useful for industrial applications.

  9. Foundation Flash Catalyst

    CERN Document Server

    Goralski, Greg

    2010-01-01

    This book offers an introduction to Flash Catalyst for designers with intermediate to advanced skills. It discusses where Catalyst sits within the production process and how it communicates with other programs. It covers all of the features of the Flash Catalyst workspace, teaching you how to create designs from scratch, how to build application designs and add functionality, and how to master the Catalyst/Flex workflow. * Introduces Flash Catalyst * Focuses on production process * Covers the interrelation between Flash Catalyst and Photoshop/Illustrator/Flex/Flash What you'll learn Starting f

  10. Metal-mediated Layer-by-layer Films of Multi-metalloporphyrin Arrays:a Novel Switchable Catalyst System

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results Metalloporphyrins as one kind of effective catalysts have received considerable attention in the past two decades,because of their selective oxidation of hydrocarbons and other organic compound under mild conditions.Great efforts have been made to oxidize or epoxidize the hydrocarbons and cycloparaffin with the oxidants such as PhIO,H2O2 catalyzed by the metalloporphyrins.However,the metalloporphyrins are normally dissolved in the reaction solution or immobilized on silica or other porous supp...

  11. A high-throughput reactor system for optimization of Mo–V–Nb mixed oxide catalyst composition in ethane ODH

    KAUST Repository

    Zhu, Haibo

    2015-01-01

    75 Mo-V-Nb mixed oxide catalysts with a broad range of compositions were prepared by a simple evaporation method, and were screened for the ethane oxidative dehydrogenation (ODH) reaction. The compositions of these 75 catalysts were systematically changed by varying the Nb loading, and the Mo/V molar ratio. Characterization by XRD, XPS, H2-TPR and SEM revealed that an intimate structure is formed among the 3 components. The strong interaction among different components leads to the formation of a new phase or an "intimate structure". The dependency of conversion and selectivity on the catalyst composition was clearly demonstrated from the results of high-throughput testing. The optimized Mo-V-Nb molar composition was confirmed to be composed of a Nb content of 4-8%, a Mo content of 70-83%, and a V content of 12-25%. The enhanced catalytic performance of the mixed oxides is obviously due to the synergistic effects of the different components. The optimized compositions for ethane ODH revealed in our high-throughput tests and the structural information provided by our characterization studies can serve as the starting point for future efforts to improve the catalytic performance of Mo-V-Nb oxides. This journal is © The Royal Society of Chemistry.

  12. 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 C12 -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 C12 alcohol and ketone. Over the Pd-modified magnesium- aluminium hydrotalcite (Pd-MgAl-HT) catalyst, a high total carbon yield (73.0 %) of C12 oxygenates can be achieved under mild conditions. In the second bed, the C12 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/SiO2 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.

  13. PEG-stabilized palladium nanoparticles: An efficient and recyclable catalyst for the selective hydrogenation of 1,5-cyclooctadiene in thermoregulated PEG biphase system

    Institute of Scientific and Technical Information of China (English)

    Tian Song Huang; Yan Hua Wang; Jing Yang Jiang; Zi Lin Jin

    2008-01-01

    Polyethylene glycol (PEG)-stabilized palladium nanoparticles were prepared and applied to the selective hydrogenation of 1,5-cyclooctadiene (1,5-COD) in thermoregulated PEG biphase system, which allows a reaction in a single-phase at a highertemperature followed by a phase split at a lower temperature. Under the optimized reaction conditions, the conversion of 1,5-CODand the selectivity of cyclooctene (COE) were 100 and 98%, respectively. The catalyst could be easily separated from the product byphase separation and reused for 6 times without evident loss in activity and selectivity.

  14. A Highly Efficient Method for Synthesis of Bisarylmethylidenes of Cyclic Ketones in [BMIm]Cl/NaOH System as New and Recyclable Catalyst

    Directory of Open Access Journals (Sweden)

    Shahrzad Javanshir

    2014-03-01

    Full Text Available An ionic liquid 1-Butyl-3-methylimidazoliumchloride[BMIm]Cl/sodium hydroxide system, was employed as a catalyst for the fast and one-pot crossed aldol-condensation of various aromatic aldehydes and cyclic ketones, to produce a variety of substituted α,α'-bis(benzylidene-cycloalkanones under neat conditions. This process is simple, efficient and environmentally benign and proceeds in high yield and short reaction times. The ionic liquid can be recycled for subsequent reactions without any appreciable loss of efficiency.

  15. A hybrid photocatalytic system comprising ZnS as light harvester and an [Fe(2)S(2)] hydrogenase mimic as hydrogen evolution catalyst.

    Science.gov (United States)

    Wen, Fuyu; Wang, Xiuli; Huang, Lei; Ma, Guijun; Yang, Jinhui; Li, Can

    2012-05-01

    Photo opportunity: A highly efficient and stable hybrid artificial photosynthetic H(2) evolution system is assembled by using a semiconductor (ZnS) as light-harvester and an [Fe(2)S(2)] hydrogenase mimic ([(μ-SPh-4-NH(2) )(2) Fe(2) (CO)(6)]) as catalyst for H(2) evolution. Photocatalytic H(2) production is achieved with more than 2607 turnovers (based on [Fe(2)S(2)]) and an initial turnover frequency of 100 h(-1) through the efficient transfer of photogenerated electrons from ZnS to the [Fe(2)S(2)] complex.

  16. New diesel catalyst systems to achieve European 2005 legislation - tested on a Volvo S60 passenger car; Neue Dieselkatalysatorsysteme zur Erreichung der europaeischen Grenzwerte 2005 - getestet an einem Volvo S60 Personenkraftwagen

    Energy Technology Data Exchange (ETDEWEB)

    Diefke, F.; Lundgren, M.; Nilsson, P. [Volvo Car Corp. (Germany); Brueck, R.; Kruse, C.; Schaper, S. [Emitec GmbH (Germany)

    2003-07-01

    In order to comply with the European 2005 legislation for diesel cars improved catalyst efficiencies for all emission components are needed. Apart form optimizing engines and engine management systems, the oxidation catalyst for converting HC and CO has to be designed for the specific demands of direct injected turbo-charged diesel engines. Because of the trade off between NO{sub x} and particulates (PM) engine out emissions, cars with higher mass in particular might require increased PM efficiency. Tests were conducted using a Volvo S60 in order to investigate the emission potential of various new diesel catalyst systems, such as PM Catalysts, Hybrid Catalysts and Pre-Turbo-charger Catalysts. (orig.) [German] Zur Einhaltung der europaeischen Stufe IV (2005) Gesetzgebung fuer Dieselfahrzeuge werden hinsichtlich aller Schadstoffe verbesserte Katalysatoreffektivitaeten benoetigt. Neben einer Optimierung des Motors und des Motorsteuerungssystems, muessen die fuer die HC und CO Umsetzung erforderlichen Oxidationskatalysatoren an die spezifischen Anforderungen von modernen direkteinspritzenden Dieselmotoren angepasst werden. Aufgrund der Wechselwirkung zwischen Stickoxid und Partikelemissionen, werden speziell Fahrzeuge mit hoeherer Fahrzeugmasse eine Partikelreduktionsmassnahme benoetigen. An einem Volvo S60 wurde das Potential verschiedener Dieselktalysatorsysteme wie Hybrid Katalysatoren, PM-Filterkatalysatoren und Vorturboladerkatalysatoren im neuen und gealterten Zustand dargestellt. (orig.)

  17. Analysis of catalyst loss of VQS system of FCCU settler%催化裂化沉降器VQS系统催化剂跑损浅析

    Institute of Scientific and Technical Information of China (English)

    李继翔

    2011-01-01

    After analysis of catalyst losses in VQS system of FCCU settler in SINOPEC Qingdao Refining & Chemical Co., Ltd., the operation of the settler was adjusted, which has solved the catalyst loss problem,ensured the normal operation of reactor and regenerator system, reduced the solid content of oil slurry and eliminated the safety potential in oil slurry system. These provide good conditions for the safe stable operation of FCC unit.%对中国石油化工股份有限公司青岛炼化分公司催化裂化装置沉降器VQS系统催化剂跑损的情况进行了分析.通过调整操作解决了催化剂跑损问题,保证了反再系统的正常运行,同时降低了油浆系统的固含量,消除了油浆系统运行的安全隐患,为装置安稳优运行提供了保障.

  18. Tethered catalysts for the hydration of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Valdez, Carlos A; Satcher, Jr., Joe H; Aines, Roger D; Wong, Sergio E; Baker, Sarah E; Lightstone, Felice C; Stolaroff, Joshuah K

    2014-11-04

    A system is provided that substantially increases the efficiency of CO.sub.2 capture and removal by positioning a catalyst within an optimal distance from the air-liquid interface. The catalyst is positioned within the layer determined to be the highest concentration of carbon dioxide. A hydrophobic tether is attached to the catalyst and the hydrophobic tether modulates the position of the catalyst within the liquid layer containing the highest concentration of carbon dioxide.

  19. Pd Close Coupled Catalyst

    Institute of Scientific and Technical Information of China (English)

    Zhong Hua SHI; Mao Chu GONG; Yao Qiang CHEN

    2006-01-01

    A catalyst comprised novel high surface area alumina support was prepared to control emission of automobiles. The results showed that prepared catalyst could satisfy the requirements of a high performance close coupled catalyst for its good catalytic activity at low temperature and good stability at high temperature.

  20. Characterization of three-way automotive catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kenik, E.A.; More, K.L. [Oak Ridge National Laboratory, TN (United States); LaBarge, W. [General Motors-AC Delco Systems, Flint, MI (United States)] [and others

    1995-05-01

    This has been the second year of a CRADA between General Motors - AC Delco Systems (GM-ACDS) and Martin Marietta Energy Systems (MMES) aimed at improved performance/lifetime of platinum-rhodium based three-way-catalysts (TWC) for automotive emission control systems. While current formulations meet existing emission standards, higher than optimum Pt-Rh loadings are often required. In additionk, more stringent emission standards have been imposed for the near future, demanding improved performance and service life from these catalysts. Understanding the changes of TWC conversion efficiency with ageing is a critical need in improving these catalysts.

  1. Synthesis of 2-Methyl-4-methoxyaniline from o-Nitrotoluene Using Pt/C and Acidic Ionic Liquid as Catalyst System

    Institute of Scientific and Technical Information of China (English)

    LIU Yingxin; LI Xiying; FANG Yanyan; ZHANG Lin

    2013-01-01

    2-Methyl-4-methoxyaniline (MMA) was synthesized by one-pot method through the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol using acidic ionic liquid and 3% Pt/C as catalyst system.The effects of ionic liquid type,dosage of ionic liquid and 3% Pt/C,reaction temperature and reaction pressure on o-nitrotoluene conversion and MMA selectivity were investigated.The results indicated that the imidazolium-based acidic ionic liquid which contains SO3H-functionalized cation showed higher selectivity to MMA than other acidic ionic liquids used in this work.Using 1-(propyl-3-sulfonate)-3-methylimidazolium hydrosulfate ([HSO3-pmim][HSO4])as the acid catalyst,the selectivity to MMA was as high as 67.6% at 97.8% of o-nitrotoluene conversion.As 3% Pt/C increased from 0.01 g to 0.025 g,the selectivity to MMA decreased from 73.4% to 62.5%,because of the hydrogenation of intermediate o-methyl-phenylhydroxylamine to o-toluidine becoming more dominant.An increase in hydrogen pressure also had obviously dramatic effect in lowering the MMA selectivity.After easy separation from the products,the catalvst system could be reused at least 3 times.

  2. Electrochemical Behavior of TiO(x)C(y) as Catalyst Support for Direct Ethanol Fuel Cells at Intermediate Temperature: From Planar Systems to Powders.

    Science.gov (United States)

    Calvillo, Laura; García, Gonzalo; Paduano, Andrea; Guillen-Villafuerte, Olmedo; Valero-Vidal, Carlos; Vittadini, Andrea; Bellini, Marco; Lavacchi, Alessandro; Agnoli, Stefano; Martucci, Alessandro; Kunze-Liebhäuser, Julia; Pastor, Elena; Granozzi, Gaetano

    2016-01-13

    To achieve complete oxidation of ethanol (EOR) to CO2, higher operating temperatures (often called intermediate-T, 150-200 °C) and appropriate catalysts are required. We examine here titanium oxycarbide (hereafter TiOxCy) as a possible alternative to standard carbon-based supports to enhance the stability of the catalyst/support assembly at intermediate-T. To test this material as electrocatalyst support, a systematic study of its behavior under electrochemical conditions was carried out. To have a clear description of the chemical changes of TiOxCy induced by electrochemical polarization of the material, a special setup that allows the combination of X-ray photoelectron spectroscopy and electrochemical measurements was used. Subsequently, an electrochemical study was carried out on TiOxCy powders, both at room temperature and at 150 °C. The present study has revealed that TiOxCy is a sufficiently conductive material whose surface is passivated by a TiO2 film under working conditions, which prevents the full oxidation of the TiOxCy and can thus be considered a stable electrode material for EOR working conditions. This result has also been confirmed through density functional theory (DFT) calculations on a simplified model system. Furthermore, it has been experimentally observed that ethanol molecules adsorb on the TiOxCy surface, inhibiting its oxidation. This result has been confirmed by using in situ Fourier transform infrared spectroscopy (FTIRS). The adsorption of ethanol is expected to favor the EOR in the presence of suitable catalyst nanoparticles supported on TiOxCy.

  3. Investigation of the influence of heated catalyst feeding system on the intensity of temperature-dependent chemical reaction in the fluidized bed apparatus

    Science.gov (United States)

    Soloveva, O. V.; Solovyev, S. A.

    2016-11-01

    A mathematical model was developed and a numerical study of operation parameters of the fluidized bed apparatus for temperature-dependent processes was performed. Fields of catalyst concentration and temperature fields were obtained. The circulation flow analysis was carried out. The effect of the influence of heated catalyst feeder on the efficiency of apparatus heating was analyzed. The change of the circulating gas flows and catalyst structures due to changes in the heated catalyst feeder was shown. The influence of the catalyst fractional composition on the efficiency of apparatus heating was studied.

  4. Enhanced gasification of wood in the presence of mixed catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Weber, S. L.; Mudge, L. K.; Sealock, Jr., L. J.; Robertus, R. J.; Mitchell, D. E.

    Experimental results obtained in laboratory investigations of steam gasification of wood in the presence of mixed catalysts are presented. These studies are designed to test the technical feasibility of producing specific gaseous products from wood by enhancing its reactivity and product specificity through the use of combined catalysts. The desired products include substitute natural gas, hydrocarbon synthesis gas and ammonia synthesis gas. The gasification reactions are controlled through the use of specific catalyst combinations and operating parameters. A primary alkali carbonate gasification catalyst impregnated into the wood combined with specific commercially available secondary catalysts produced the desired products. A yield of 50 vol % methane was obtained with a randomly mixed combination of a commercial nickel methanation catalyst and silica-alumina cracking catalyst at a weight ratio of 3:1 respectively. Steam gasification of wood in the presence of a commercial Si-Al cracking catalyst produced the desired hydrocarbon synthesis gas. Hydrogen-to-carbon monoxide ratios needed for Fischer-Tropsch synthesis of hydrocarbons were obtained with this catalyst system. A hydrogen-to-nitrogen ratio of 3:1 for ammonia synthesis gas was achieved with steam-air gasification of wood in the presence of catalysts. The most effective secondary catalyst system employed to produce the ammonia synthesis gas included two commercially prepared catalysts formulated to promote the water-gas shift reaction.

  5. Ruthenium-based olefin metathesis catalysts bearing pH-responsive ligands: External control of catalyst solubility and activity

    Science.gov (United States)

    Balof, Shawna Lynn

    2011-12-01

    Sixteen novel, Ru-based olefin metathesis catalysts bearing pH responsive ligands were synthesized. The pH-responsive groups employed with these catalysts included dimethylamino (NMe2) modified NHC ligands as well as N-donor dimethylaminopyridine (DMAP) and 3-(o-pyridyl)propylidene ligands. These pH-responsive ligands provided the means by which the solubility and/or activity profiles of the catalysts produced could be controlled via acid addition. The main goal of this dissertation was to design catalyst systems capable of performing ring opening metathesis (ROMP) and ring closing metathesis (RCM) reactions in both organic and aqueous media. In an effort to quickly gain access to new catalyst structures, a template synthesis for functionalized NHC ligand precursors was designed, in addition to other strategies, to obtain ligand precursors with ancillary NMe2 groups. Kinetic studies for the catalysts produced from these precursors showed external control of catalyst solubility was afforded via protonation of the NMe2 groups of their NHC ligands. Additionally, this protonation afforded external control of catalyst propagation rates for several catalysts. This is the first known independent external control for the propagation rates of ROMP catalysts. The incorporation of pH-responsive N-donor ligands into catalyst structures also provided the means for the external control of metathesis activity, as the protonation of these ligands resulted in an increased initiation rate based on their fast and irreversible dissociation from the metal center. The enhanced external control makes these catalysts applicable to a wide range of applications, some of which have been explored by us and/or through collaboration. Three of the catalysts designed showed remarkable metathesis activity in aqueous media. These catalysts displayed comparable RCM activity in aqueous media to a class of water-soluble catalysts reported by Grubbs et al., considered to be the most active catalyst for

  6. Renovation and Reuse of Reactive Dyeing Effluent by a Novel Heterogeneous Fenton System Based on Metal Modified PTFE Fibrous Catalyst/H2O2

    Directory of Open Access Journals (Sweden)

    Bing Li

    2013-01-01

    Full Text Available Cu-Fe bimetallic grafted polytetrafluoroethylene (PTFE fiber complexes were prepared and optimized as the novel heterogeneous Fenton catalysts for the degradation of reactive dyes under UV irradiation. Cotton fabrics were dyed with three reactive dyes, namely, Reactive Red 195, Reactive Yellow 145, and Reactive Blue 222, in tap fresh water using exhaustion process. The spent dyeing effluents were then collected and degraded with the optimized Cu-Fe bimetallic grafted PTFE fiber complex/H2O2 system. The treated dyeing effluents were characterized and reused for the dyeing of cotton fabrics through the same process. The effect of reuse process number on quality of the dyed cotton fabrics was examined. The results indicated that the Cu-Fe bimetallic modified PTFE fiber complex with a Cu/Fe molar ratio of 2.87 was found to be the most effective fibrous catalyst, which enhanced complete decolorization of the treated dyeing effluents with H2O2 in 4 h. However, the TOC removal for the treated dyeing effluents was below 80%. The dyeing quality was not affected for three successive cycles. The increase in residual TOC value influences fourth dyeing cycle. Further TOC reduction of the treated effluents is needed for its repeated reuse in more than three dyeing cycles.

  7. Engineering design and testing of a ground water remediation system using electrolytically generated hydrogen with a palladium catalyst for dehalogenation of chlorinated hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, R.

    1997-12-01

    Recent studies have shown that dissolved hydrogen causes rapid dehalogenation of chlorinated hydrocarbons in the presence of a palladium catalyst. The speed and completeness of these reactions offer advantages in designing remediation technologies for certain ground water contamination problems. However, a practical design challenge arises in the need to saturate the aqueous phase with hydrogen in an expeditious manner. To address this issue, a two-stage treatment reactor has been developed. The first stage consists of an electrolytic cell that generates hydrogen by applying a voltage potential across the influent water stream. The second stage consists of a catalyst column of palladium metal supported on alumina beads. A bench-scale reactor has been used to test this design for treating ground water contaminated with trichloroethene and other chlorinated hydrocarbons. In influent streams containing contaminant concentrations up to 4 ppm, initial results confirm that destruction efficiencies greater than 95% may be achieved with residence times short enough to allow practical implementation in specially designed flow-through treatment wells. Results from the bench-scale tests are being used to design a pilot ground water treatment system.

  8. Plasmonic Ag-pillared rectorite as catalyst for degradation of 2,4-DCP in the H2O2-containing system under visible light irradiation.

    Science.gov (United States)

    Chen, Yunfang; Fang, Jianzhang; Lu, Shaoyou; Wu, Yan; Chen, Dazhi; Huang, Liyan; Cheng, Cong; Ren, Lu; Zhu, Ximiao; Fang, Zhanqiang

    2015-10-30

    This study aims at photocatalytic degradation of 2,4-DCP with the assistance of H2O2 in aqueous solution by a composite catalyst of Ag-rectorite. The catalysts were prepared via a novel thermal decomposition method followed after the cation-exchange process. The synthesized nano-materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface analyzer, Ultraviolet-visible light (UV-vis) absorption spectra, field-emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The different mechanisms of degradation process with or without visible light irradiation were discussed, respectively. Moreover, the degradation efficiency of 2,4-DCP wastewater under Ag-rectorite/H2O2/visible light system was investigated by series of experiments, concerning on effects of major operation factors, such as H2O2 dosage and the initial pH value. The highest degradation rate was observed when adding 0.18 mL H2O2 into 50 mL 2,4-DCP solution, and the optimal pH value was 4 for the reaction. Afterwards, total organic carbon (TOC) experiments were carried out to evaluate the mineralization ratio of 2,4-DCP.

  9. Engineering design and testing of a ground water remediation system using electrolytically generated hydrogen with a palladium catalyst for dehalogenation of chlorinated hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, R.

    1997-12-01

    Recent studies have shown that dissolved hydrogen causes rapid dehalogenation of chlorinated hydrocarbons in the presence of a palladium catalyst. The speed and completeness of these reactions offer advantages in designing remediation technologies for certain ground water contamination problems. However, a practical design challenge arises in the need to saturate the aqueous phase with hydrogen in an expeditious manner. To address this issue, a two-stage treatment reactor has been developed. The first stage consists of an electrolytic cell that generates hydrogen by applying a voltage potential across the influent water stream. The second stage consists of a catalyst column of palladium metal supported on alumina beads. A bench-scale reactor has been used to test this design for treating ground water contaminated with trichloroethene and other chlorinated hydrocarbons. In influent streams containing contaminant concentrations up to 4 ppm, initial results confirm that destruction efficiencies greater than 95% may be achieved with residence times short enough to allow practical implementation in specially designed flow-through treatment wells. Results from the bench-scale tests are being used to design a pilot ground water treatment system.

  10. Steam Reforming of Glycerol for Hydrogen Production over Catalyst

    OpenAIRE

    Sadanandam, G.; Sreelatha, N.; Phanikrishna Sharma, M. V.; Kishta Reddy, S.; B. Srinivas; K. Venkateswarlu; T. Krishnudu; Subrahmanyam, M; Durga Kumari, V.

    2012-01-01

    The performance of Ni/SiO2 catalyst for glycerol reforming has been investigated in fixed-bed reactor using careful tailoring of the operational conditions. In this paper, a commercial Engelhard catalyst has been sized and compared to gas product distribution versus catalyst size, water-to-carbon ratio, and stability of the catalyst system. Ni/SiO2 catalysts of three sizes (2×2, 2×4, and 3×5 mm) are evaluated using glycerol: water mixture at 600°C to produce 2 L H2 g−1 cat h−1. The results in...

  11. Physico-chemical characterisations and catalytic performance of Ni-based catalyst systems for dry reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Vlach, K.; Hoang, D.L.; Schneider, M.; Pohl, M.M.; Armbruster, U.; Martin, A. [Rostock Univ. (Germany). Leibniz-Institut fuer Katalyse e.V.

    2012-07-01

    In this study, ternary perovskite type oxides LaNi{sub x}Cu{sub 1-x}O{sub 3} (x = 0, 0.2, 0.5, 0.8, 1) were synthesized using NaOH and diethylenetriaminepentaacetic acid (H{sub 5}DTPA). The catalysts resulting from perovskite precursors exhibit catalytic activities for CO{sub 2} reforming of CH{sub 4} at 700 C that increase with a higher Ni content. Characterization methods showed that the activation led to formation of small metallic Ni/Cu particles. Methane and carbon dioxide conversions varied from 20 to 65% for CH{sub 4} and 3 to 58% for CO{sub 2}. Selectivities from 46 to 93% for CO and from 4 to 64% for H{sub 2} were obtained. (orig.)

  12. Influence of Organoboron Compounds on Ethylene Polymerization Using Cp2ZrCl2/MAO as Catalyst System

    Directory of Open Access Journals (Sweden)

    Luis Alexandro Valencia López

    2014-01-01

    Full Text Available Organoboron compounds of nonionic and ionic nature, tris(pentafluorophenylborane, and N,N-dimethylanilinium tetra(pentafluorophenylborate were evaluated to act in conjunction with MAO as activators on ethylene polymerization by using the catalyst Cp2ZrCl2. A decrease on the catalytic activity was observed in both cases in relation with a reference polyethylene which was synthesized in absence of any organoboron compound. An increase on the crystallinity degree and molecular weight, as well as an improvement in thermal and dynamic-mechanical properties, was observed in polyethylenes synthetized in presence of tris(pentafluorophenylborane. A low density polyethylene with improved thermal stability was obtained when N,N-dimethylanilinium tetra(pentafluorophenylborate was employed as activator.

  13. Light alkane conversion processes - Suprabiotic catalyst systems for selective oxidation of light alkane gases to fuel oxygenates

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, J.E.

    1992-01-01

    The objective of the work presented in this paper is to develop new, efficient catalysts for the selective transformation of the light alkanes in natural gas to alcohols for use as liquid transportation fuels, fuel precursors and chemical products. There currently exists no DIRECT one-step catalytic air-oxidation process to convert these substrates to alcohols. Such a one-step route would represent superior useful technology for the utilization of natural gas and similar refinery-derived light hydrocarbon streams. Processes for converting natural gas or its components (methane, ethane, propane, and the butanes) to alcohols for use as motor fuels, fuel additives or fuel precursors will not only add a valuable alternative to crude oil but will produce a clean-burning, high octane alternative to conventional gasoline.

  14. Light alkane conversion processes - Suprabiotic catalyst systems for selective oxidation of light alkane gases to fuel oxygenates.

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, J.E.

    1992-07-01

    The objective of the work presented in this paper is to develop new, efficient catalysts for the selective transformation of the light alkanes in natural gas to alcohols for use as liquid transportation fuels, fuel precursors and chemical products. There currently exists no DIRECT one-step catalytic air-oxidation process to convert these substrates to alcohols. Such a one-step route would represent superior useful technology for the utilization of natural gas and similar refinery-derived light hydrocarbon streams. Processes for converting natural gas or its components (methane, ethane, propane, and the butanes) to alcohols for use as motor fuels, fuel additives or fuel precursors will not only add a valuable alternative to crude oil but will produce a clean-burning, high octane alternative to conventional gasoline.

  15. Catalyst Alloys Processing

    Science.gov (United States)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  16. Resin Catalyst Hybrids

    Institute of Scientific and Technical Information of China (English)

    S. Asaoka

    2005-01-01

    @@ 1Introduction: What are resin catalyst hybrids? There are typically two types of resin catalyst. One is acidic resin which representative is polystyrene sulfonic acid. The other is basic resin which is availed as metal complex support. The objective items of this study on resin catalyst are consisting of pellet hybrid, equilibrium hybrid and function hybrid of acid and base,as shown in Fig. 1[1-5].

  17. Stereospecific olefin polymerization catalysts

    Science.gov (United States)

    Bercaw, John E.; Herzog, Timothy A.

    1998-01-01

    A metallocene catalyst system for the polymerization of .alpha.-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula ##STR1## wherein: R.sup.1, R.sup.2, and R.sup.3 are independently selected from the group consisting of hydrogen, C.sub.1 to C.sub.10 alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C.sub.1 to C.sub.10 alkyls as a substituent, C.sub.6 to C.sub.15 aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si(R.sup.8).sub.3 where R.sup.8 is selected from the group consisting of C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; R.sup.4 and R.sup.6 are substituents both having van der Waals radii larger than the van der Waals radii of groups R.sup.1 and R.sup.3 ; R.sup.5 is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E.sup.1, E.sup.2 are independently selected from the group consisting of Si(R.sup.9).sub.2, Si(R.sup.9).sub.2 --Si(R.sup.9).sub.2, Ge(R.sup.9).sub.2, Sn(R.sup.9).sub.2, C(R.sup.9).sub.2, C(R.sup.9).sub.2 --C(R.sup.9).sub.2, where R.sup.9 is C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; and the ligand may have C.sub.S or C.sub.1 -symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from .alpha.-olefin monomers.

  18. Removal of H2S from Biogas by Iron (Fe3+ Doped MgO on Ceramic Honeycomb Catalyst using Double Packed Columns System

    Directory of Open Access Journals (Sweden)

    Juntima Chungsiriporn

    2010-03-01

    Full Text Available Hydrogen sulfide is a toxic and corrosive in nature, gas should be safely removed from the biogas streams before subjecting into the fuel cell. Fe3+ doped magnesium oxide was synthesized using sol-gel technique and dip coating process of Fe3+ doped MgO on foam ceramic honeycomb. XRD and SEM indicate that Fe3+ in Fe3+ doped MgO on foam ceramic honeycomb catalyst is finely dispersed in the MgO support. Performance of the synthesized Fe3+ doped magnesium oxide on the honeycomb catalyst was examined for hydrogen sulfide (H2S oxidation by double packed column scrubbers. The absorption column was used for H2S scrubbing from biogas by deionized water absorption and catalytic column was used as catalyst bed for degradation of absorbed H2S in scrubbing water. In the catalytic column, counter current flow of the scrubbing water and air through the catalyst pack was performed for H2S oxidation accompany with catalyst regeneration. System capacity for H2S removal from gas stream showed 98% constant along 3 hr testing time at room temperature.

  19. Polymerization of ethyl methacrylate under the influence of ultrasound assisted a new multi-site phase-transfer catalyst system--a kinetic study.

    Science.gov (United States)

    Sankar, Kavitha; Rajendran, Venugopal

    2013-01-01

    The kinetics of multi-site phase-transfer catalyzed free radical polymerisation of ethyl methacrylate (EMA) using potassium peroxy disulphate (PDS) as a water soluble initiator and newly synthesized 1,4-dihexadecylpyrazine-1,4-diium dibromide as multi-site phase-transfer catalyst (MPTC) has been investigated in ethyl acetate/water two phase system at constant temperature 55 ± 1 °C under nitrogen atmosphere and ultrasound irradiation conditions. The rate of polymerization increases with an increase in concentrations of EMA, PDS and MPTC. The order with respect to monomer, initiator and MPTC were found to be 1.03, 0.52 and 0.53, respectively. Based on the observed results a suitable mechanism has been proposed to account for the experimental observations and its significance was discussed.

  20. Copolymerization of 1-hexene and 1-dodecene with 1,3-butadiene by a versatate/diisobutylaluminum hydride/t-butyl chloride catalyst system

    Directory of Open Access Journals (Sweden)

    Gustavo Monteiro da Silva

    2014-01-01

    Full Text Available The aim of this study was to incorporate an alpha-olefin (1-hexene or 1-dodecene in a high cis polybutadiene chain, using a neodymium versatate/diisobutylaluminum hydride/t-butyl chloride catalyst system. The influence of alpha-olefin on polymerization reaction and polymer characteristics, using different weight ratios of butadiene/α-olefin, was evaluated. The copolymers were characterized by SEC, FTIR, NMR, TGA and viscosimetric analysis. The thermal stability of the polymer tended to increase with incorporation of alpha-olefins, while its microstructure was not affected. The weight average molecular mass (Mw tended to increase and the polymerization conversion tended to decrease with increasing alpha-olefins content. The copolymers showed a lower intrinsic viscosity than for the homopolymer. The results indicated that the alpha-olefins were incorporated in the polybutadiene chain.

  1. Surfactant-coated Candida rugosa Lipase as Catalyst for Hydrolysis of Olive Oil in Solvent-Free Two-Phase System

    Institute of Scientific and Technical Information of China (English)

    宋宝东; 丁辉; 吴金川; HayashiY.; TalukderMMR; 王世昌

    2003-01-01

    The surfactant-coated Candida rugosa lipase was used as catalyst for hydrolysis of olive oil in two-phase system consisting of olive oil and phosphate buffer without organic solvent. For both the coated and native lipases,the optimal buffer/oil volume ratio of 1.0, aqueous pH 6.8 and reaction temperature 30℃ were determined. The maximum activity of the coated lipase was ca 1.3 times than that of the native lipase. The half-life of the coated lipase in olive oil and the native lipase in phosphate buffer was ca 9 h and 12 h, and the final residual activity was 27% and 20% of their initial values, respectively. The final substrate conversion by the coated lipase was ca 20% higher than that of the native lipase.

  2. Aqueous Biphasic Systems for the Synthesis of Formates by Catalytic CO2 Hydrogenation: Integrated Reaction and Catalyst Separation for CO2 -Scrubbing Solutions.

    Science.gov (United States)

    Scott, Martin; Blas Molinos, Beatriz; Westhues, Christian; Franciò, Giancarlo; Leitner, Walter

    2017-03-22

    Aqueous biphasic systems were investigated for the production of formate-amine adducts by metal-catalyzed CO2 hydrogenation, including typical scrubbing solutions as feedstocks. Different hydrophobic organic solvents and ionic liquids could be employed as the stationary phase for cis-[Ru(dppm)2 Cl2 ] (dppm=bis-diphenylphosphinomethane) as prototypical catalyst without any modification or tagging of the complex. The amines were found to partition between the two phases depending on their structure, whereas the formate-amine adducts were nearly quantitatively extracted into the aqueous phase, providing a favorable phase behavior for the envisaged integrated reaction/separation sequence. The solvent pair of methyl isobutyl carbinol (MIBC) and water led to the most practical and productive system and repeated use of the catalyst phase was demonstrated. The highest single batch activity with a TOFav of approximately 35 000 h(-1) and an initial TOF of approximately 180 000 h(-1) was achieved in the presence of NEt3 . Owing to higher stability, the highest productivities were obtained with methyl diethanolamine (Aminosol CST 115) and monoethanolamine (MEA), which are used in commercial scale CO2 -scrubbing processes. Saturated aqueous solutions (CO2 overpressure 5-10 bar) of MEA could be converted into the corresponding formate adducts with average turnover frequencies up to 14×10(3)  h(-1) with an overall yield of 70 % based on the amine, corresponding to a total turnover number of 150 000 over eleven recycling experiments. This opens the possibility for integrated approaches to carbon capture and utilization.

  3. Advanced Petroleum-Based Fuels - Diesel Emissions Project (APBF-DEC): 2,000-Hour Performance of a NOx Adsorber Catalyst and Diesel Particle Filter System for a Medium-Duty, Pick-Up Diesel Engine Platform; Final Report

    Energy Technology Data Exchange (ETDEWEB)

    2007-03-01

    Presents the results of a 2,000-hour test of an emissions control system consisting of a nitrogen oxides adsorber catalyst in combination with a diesel particle filter, advanced fuels, and advanced engine controls in an SUV/pick-up truck vehicle platform.

  4. Advanced Petroleum-Based Fuels - Diesel Emissions Project (APBF-DEC): 2,000-Hour Performance of a NOx Adsorber Catalyst and Diesel Particle Filter System for a Medium-Duty, Pick-Up Diesel Engine Platform; Final Report

    Energy Technology Data Exchange (ETDEWEB)

    2007-03-01

    Presents the results of a 2,000-hour test of an emissions control system consisting of a nitrogen oxides adsorber catalyst in combination with a diesel particle filter, advanced fuels, and advanced engine controls in an SUV/pick-up truck vehicle platform.

  5. Synthesis and application of aryl-ferrocenyl(pseudo-biarylic) complexes. Part 5. Design and synthesis of a new type of ferrocene-based planar chiral DMAP analogues. A new catalyst system for asymmetric nucleophilic catalysis

    DEFF Research Database (Denmark)

    Seitzberg, J.G; Dissing, C; Søtofte, Inger

    2005-01-01

    A new first-generation catalyst system for nucleophilic catalysis has been developed. It is based on a planar chiral ferrocene skeleton with either the potent nucleophile 4-(dimethylamino)pyridine (DMAP) or the related 4-nitropyridine N-oxide attached in either the 2- or the 3-position...

  6. Modulation of the Reactivity, Stability and Substrate- and Enantioselectivity of an Epoxidation Catalyst by Noncovalent Dynamic Attachment of a Receptor Functionality - Aspects on the Mechanism of the Jacobsen-Katsuki Epoxidation Applied to a Supramolecular System

    DEFF Research Database (Denmark)

    Jónsson, Stefán; Odille, Fabrice G. J.; Norrby, Per-Ola;

    2006-01-01

    model of the metal-free system 4 + 5 refutes the earlier assumption that macrocycle 1 is the predominant form of catalyst 2 under the standard epoxidation reaction conditions with 2 + 3. Evidence are provided that receptor-binding substrates and nonbinding substrates, respectively, are epoxidised by two...

  7. Nano-catalysts: Bridging the gap between homogeneous and heterogeneous catalysis

    Science.gov (United States)

    Functionalized nanoparticles have emerged as sustainable alternatives to conventional materials, as robust, high-surface-area heterogeneous catalyst supports. We envisioned a catalyst system, which can bridge the homogenous and heterogeneous system. Postsynthetic surface modifica...

  8. Magnetic catalyst bodies

    NARCIS (Netherlands)

    Teunissen, Wendy; Bol, A.A.; Geus, John W.

    2001-01-01

    After a discussion about the importance of the size of the catalyst bodies with reactions in the liquid-phase with a suspended catalyst, the possibilities of magnetic separation are dealt with. Deficiencies of the usual ferromagnetic particles are the reactivity and the clustering of the particles.

  9. External Catalyst Breakup Phenomena

    Science.gov (United States)

    1976-06-01

    14-18 Mesh Catalyst 127 4-12 Hot Gas Thermal Fatigue Test Results for 25-30 Mesh Catalyst 128 4-13 Hot Gas Thermal Aging Test Results 131 - 19 - LISI ...magnitude of the thermal and internal pressure solution3, These solucions siu- Li.L fti’r oir =ztcrii ad the pressure and temperature profiles of

  10. Catalyst for Ammonia Oxidation

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

  11. Reducible oxide based catalysts

    Science.gov (United States)

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.

    2010-04-06

    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  12. 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...

  13. Catalysts and process for liquid hydrocarbon fuel production

    Energy Technology Data Exchange (ETDEWEB)

    White, Mark G.; Ranaweera, Samantha A.; Henry, William P.

    2016-08-02

    The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality distillates, gasoline components, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel supported bimetallic ion complex catalyst for conversion, and provides methods of preparing such novel catalysts and use of the novel catalysts in the process and system of the invention.

  14. Genetics Home Reference: boomerang dysplasia

    Science.gov (United States)

    ... affinity in the absence of major structural disturbance: Insights from the crystal structures of filamin B actin ... healthcare professional . About Genetics Home Reference Site Map Customer Support Selection Criteria for Links USA.gov Copyright ...

  15. Protic acid immobilized on solid support as an extremely efficient recyclable catalyst system for a direct and atom economical esterification of carboxylic acids with alcohols.

    Science.gov (United States)

    Chakraborti, Asit K; Singh, Bavneet; Chankeshwara, Sunay V; Patel, Alpesh R

    2009-08-21

    A convenient and clean procedure of esterification is reported by direct condensation of equimolar amounts of carboxylic acids with alcohols catalyzed by an easy to prepare catalyst system of perchloric acid immobilized on silica gel (HClO(4)-SiO(2)). The direct condensation of aryl, heteroaryl, styryl, aryl alkyl, alkyl, cycloalkyl, and long-chain aliphatic carboxylic acids with primary/secondary alkyl/cycloalkyl, allyl, propargyl, and long-chain aliphatic alcohols has been achieved to afford the corresponding esters in excellent yields. Chiral alcohol and N-t-Boc protected chiral amino acid also resulted in ester formation with the representative carboxylic acid or alcohol without competitive N-t-Boc deprotection and detrimental effect on the optical purity of the product demonstrating the mildness and chemoselectivity of the procedure. The esters of long-chain (>C(10)) acids and alcohols are obtained in high yields. The catalyst is recovered and recycled without significant loss of activity. The industrial application of the esterification process is demonstrated by the synthesis of prodrugs of ibuprofen and a few commercial flavoring agents. Other protic acids such as H(2)SO(4), HBr, TfOH, HBF(4), and TFA that were adsorbed on silica gel were less effective compared to HClO(4)-SiO(2) following the order HClO(4)-SiO(2) > H(2)SO(4)-SiO(2) > HBr-SiO(2) > TfOH-SiO(2) > HBF(4)-SiO(2) approximately TFA-SiO(2). When HClO(4) was immobilized on other solid supports the catalytic efficiency followed the order HClO(4)-SiO(2) > HClO(4)-K10 > HClO(4)-Al(2)O(3) (neutral) > HClO(4)-Al(2)O(3) (acidic) > HClO(4)-Al(2)O(3) (basic).

  16. Idea of environmental catalyst and its application; Kankyo shokubai no hasso to sono riyo

    Energy Technology Data Exchange (ETDEWEB)

    Inumaru, K. [The University of Tokyo, Tokyo (Japan)

    1997-10-20

    The catalyst creating environmental conservation and comfortable environment is generally named an `environmental catalyst (EC).` EC is roughly classified into direct and indirect type ECs. Purification catalysts for automobile exhaust gas, and catalysts for chemical production process are under investigation as direct and indirect type ECs, respectively. The catalyst was found which can remove NOx under the coexistence of oxygen by using hydrocarbon as reductant. In addition, the practical exhaust gas purification catalyst was also developed for lean-burn engines by combining noble metal catalysts with NOx absorbing materials or zeolite superior in reductant adsorbing power. {epsilon}-caprolactam as raw material of nylon 6 is synthesized from cyclohexanoneoxime through Beckmann` rearrangement reaction. Zeolite system solid catalysts using no ammonia are under investigation. An environment-friendly synthesis method using not phosgene but catalyst was proposed for production of dimethyl carbonate. How to utilize catalysts for global material circulation remains unsolved for the future study. 5 refs.

  17. Unraveling the Active Site in Copper-ceria Systems for the Water Gas Shift Reaction: In-situ Characterization of an Inverse Powder CeO2-x/CuO-Cu Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, J.A.; Barrio, L.; Estrella, M.; Zhou, G.; Wen, W.; Hanson, J.C.; Hungría, A.B.; Hornés, A.; Fernández-García, M.; Arturo Martínez-Arias, A.

    2010-03-04

    An inverse powder system composed of CeO{sub 2} nanoparticles dispersed over a CuO-Cu matrix is proposed as a novel catalyst for the water-gas shift reaction. This inverse CeO{sub 2}/CuO-Cu catalyst exhibits a higher activity than standard Cu/CeO{sub 2} catalysts. In situ synchrotron characterization techniques were employed to follow the structural changes of CeO{sub 2}/CuO-Cu under reaction conditions. Time-resolved X-ray diffraction experiments showed the transformation of CuO to metallic Cu via a Cu{sub 2}O intermediate. Short-order structural changes were followed by pair distribution function analysis and corroborated the results obtained by diffraction. Moreover, X-ray absorption spectroscopy also revealed oxidation state changes from Cu{sup 2+} to Cu{sup 0} and the partial reduction of CeOx nanoparticles. The activity data obtained by mass spectrometry revealed that hydrogen production starts once the copper has been fully reduced. The strong interaction of ceria and copper boosted the catalytic performance of the sample. The inverse catalyst was active at low temperatures, stable to several reaction runs and to redox cycles. These characteristics are highly valuable for mobile fuel cell applications. The active phases of the inverse CeO{sub 2}/CuO-Cu catalyst are partially reduced ceria nanoparticles strongly interacting with metallic copper. The nature and structure of the ceria nanoparticles are of critical importance because they are involved in processes related to water dissociation over the catalyst surface.

  18. Unraveling the Active Site in Copper-Ceria Systems for the Water-Gas Shift Reaction: In Situ Characterization of an Inverse Powder CeO2-x/CuO-Cu Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Barrio, L.; Estrella, M; Zhou, G; Wen, W; Hanson, J; Hungria, A; Hornes, A; Fernandez-Garcia, M; Martinez-Arias, A; Rodriguez, J

    2010-01-01

    An inverse powder system composed of CeO{sub 2} nanoparticles dispersed over a CuO-Cu matrix is proposed as a novel catalyst for the water-gas shift reaction. This inverse CeO{sub 2}/CuO-Cu catalyst exhibits a higher activity than standard Cu/CeO{sub 2} catalysts. In situ synchrotron characterization techniques were employed to follow the structural changes of CeO{sub 2}/CuO-Cu under reaction conditions. Time-resolved X-ray diffraction experiments showed the transformation of CuO to metallic Cu via a Cu{sub 2}O intermediate. Short-order structural changes were followed by pair distribution function analysis and corroborated the results obtained by diffraction. Moreover, X-ray absorption spectroscopy also revealed oxidation state changes from Cu{sup 2+} to Cu{sup 0} and the partial reduction of CeO{sub x} nanoparticles. The activity data obtained by mass spectrometry revealed that hydrogen production starts once the copper has been fully reduced. The strong interaction of ceria and copper boosted the catalytic performance of the sample. The inverse catalyst was active at low temperatures, stable to several reaction runs and to redox cycles. These characteristics are highly valuable for mobile fuel cell applications. The active phases of the inverse CeO{sub 2}/CuO-Cu catalyst are partially reduced ceria nanoparticles strongly interacting with metallic copper. The nature and structure of the ceria nanoparticles are of critical importance because they are involved in processes related to water dissociation over the catalyst surface.

  19. Covalent anchoring of a racemization catalyst to CALB-beads: towards dual immobilization of DKR catalysts

    NARCIS (Netherlands)

    Wieczorek, B.; Träff, A.; Krumlinde, P.; Dijkstra, H.P.; Egmond, M.R.; van Koten, G.; Bäckvall, J.-E.; Klein Gebbink, R.J.M.

    2011-01-01

    The preparation of a heterogeneous bifunctional catalytic system, combining the catalytic properties of an organometallic catalyst (racemization) with those of an enzyme (enantioselective acylation) is described. A novel ruthenium phosphonate inhibitor was synthesized and covalently anchored to a

  20. Catalysts, methods of making catalysts, and methods of use

    KAUST Repository

    Renard, Laetitia

    2014-03-06

    Embodiments of the present disclosure provide for catalysts, methods of making catalysts, methods of using catalysts, and the like. In an embodiment, the method of making the catalysts can be performed in a single step with a metal nanoparticle precursor and a metal oxide precursor, where a separate stabilizing agent is not needed.

  1. Synthesis and Understanding of Novel Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Stair, Peter C. [Northwestern University

    2013-07-09

    The research took advantage of our capabilities to perform in-situ and operando Raman spectroscopy on complex systems along with our developing expertise in the synthesis of uniform, supported metal oxide materials to investigate relationships between the catalytically active oxide composition, atomic structure, and support and the corresponding chemical and catalytic properties. The project was organized into two efforts: 1) Synthesis of novel catalyst materials by atomic layer deposition (ALD). 2) Spectroscopic and chemical investigations of coke formation and catalyst deactivation. ALD synthesis was combined with conventional physical characterization, Raman spectroscopy, and probe molecule chemisorption to study the effect of supported metal oxide composition and atomic structure on acid-base and catalytic properties. Operando Raman spectroscopy studies of olefin polymerization leading to coke formation and catalyst deactivation clarified the mechanism of coke formation by acid catalysts.

  2. Catalyst in Basic Oleochemicals

    Directory of Open Access Journals (Sweden)

    Eva Suyenty

    2007-10-01

    Full Text Available Currently Indonesia is the world largest palm oil producer with production volume reaching 16 million tones per annum. The high crude oil and ethylene prices in the last 3 – 4 years contribute to the healthy demand growth for basic oleochemicals: fatty acids and fatty alcohols. Oleochemicals are starting to replace crude oil derived products in various applications. As widely practiced in petrochemical industry, catalyst plays a very important role in the production of basic oleochemicals. Catalytic reactions are abound in the production of oleochemicals: Nickel based catalysts are used in the hydrogenation of unsaturated fatty acids; sodium methylate catalyst in the transesterification of triglycerides; sulfonic based polystyrene resin catalyst in esterification of fatty acids; and copper chromite/copper zinc catalyst in the high pressure hydrogenation of methyl esters or fatty acids to produce fatty alcohols. To maintain long catalyst life, it is crucial to ensure the absence of catalyst poisons and inhibitors in the feed. The preparation methods of nickel and copper chromite catalysts are as follows: precipitation, filtration, drying, and calcinations. Sodium methylate is derived from direct reaction of sodium metal and methanol under inert gas. The sulfonic based polystyrene resin is derived from sulfonation of polystyrene crosslinked with di-vinyl-benzene. © 2007 BCREC UNDIP. All rights reserved.[Presented at Symposium and Congress of MKICS 2007, 18-19 April 2007, Semarang, Indonesia][How to Cite: E. Suyenty, H. Sentosa, M. Agustine, S. Anwar, A. Lie, E. Sutanto. (2007. Catalyst in Basic Oleochemicals. Bulletin of Chemical Reaction Engineering and Catalysis, 2 (2-3: 22-31.  doi:10.9767/bcrec.2.2-3.6.22-31][How to Link/DOI: http://dx.doi.org/10.9767/bcrec.2.2-3.6.22-31 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/6

  3. Catalysts and process for liquid hydrocarbon fuel production

    Science.gov (United States)

    White, Mark G; Liu, Shetian

    2014-12-09

    The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality gasoline components, aromatic compounds, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel molybdenum-zeolite catalyst in high pressure hydrogen for conversion, as well as a novel rhenium-zeolite catalyst in place of the molybdenum-zeolite catalyst, and provides for use of the novel catalysts in the process and system of the invention.

  4. ALKALI RESISTANT CATALYST

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention concerns the selective removal of nitrogen oxides (NOx) from gasses. In particular, the invention concerns a process, a catalyst and the use of a catalyst for the selective removal of nitrogen oxides in the presence of ammonia from gases containing a significant amount...... of alkali metal and/or alkali-earth compounds which process comprises using a catalyst combined of (i) a formed porous superacidic support, said superacidic support having an Hammett acidity stronger than Ho=-12, and (ii) a metal oxide catalytic component deposited on said superacidic support selected from...

  5. Catalyst for Carbon Monoxide Oxidation

    Science.gov (United States)

    Davis, Patricia; Brown, Kenneth; VanNorman, John; Brown, David; Upchurch, Billy; Schryer, David; Miller, Irvin

    2010-01-01

    In many applications, it is highly desirable to operate a CO2 laser in a sealed condition, for in an open system the laser requires a continuous flow of laser gas to remove the dissociation products that occur in the discharge zone of the laser, in order to maintain a stable power output. This adds to the operating cost of the laser, and in airborne or space applications, it also adds to the weight penalty of the laser. In a sealed CO2 laser, a small amount of CO2 gas is decomposed in the electrical discharge zone into corresponding quantities of CO and O2. As the laser continues to operate, the concentration of CO2 decreases, while the concentrations of CO and O2 correspondingly increase. The increasing concentration of O2 reduces laser power, because O2 scavenges electrons in the electrical discharge, thereby causing arcing in the electric discharge and a loss of the energetic electrons required to boost CO2 molecules to lasing energy levels. As a result, laser power decreases rapidly. The primary object of this invention is to provide a catalyst that, by composition of matter alone, contains chemisorbed water within and upon its structure. Such bound moisture renders the catalyst highly active and very long-lived, such that only a small quantity of it needs to be used with a CO2 laser under ambient operating conditions. This object is achieved by a catalyst that consists essentially of about 1 to 40 percent by weight of one or more platinum group metals (Pt, Pd, Rh, Ir, Ru, Os, Pt being preferred); about 1 to 90 percent by weight of one or more oxides of reducible metals having multiple valence states (such as Sn, Ti, Mn, Cu, and Ce, with SnO2 being preferred); and about 1 to 90 percent by weight of a compound that can bind water to its structure (such as silica gel, calcium chloride, magnesium sulfate, hydrated alumina, and magnesium perchlorate, with silica gel being preferred). Especially beneficial results are obtained when platinum is present in the

  6. Lacunary Keggin Polyoxotungstate as Reaction-controlled Phasetransfer Catalyst for Catalytic Epoxidation of Olefins

    Institute of Scientific and Technical Information of China (English)

    LI,Ming-Qiang(李明强); JIAN,Xi-Gao(蹇锡高); YANG,Yong-Qiang(杨永强)

    2004-01-01

    A new reaction-controlled phase-transfer catalyst system, lacunary Keggin polyoxotungstate [C7H7N(CH3)3]9PW9O34 has been synthesized and used for catalytic epoxidation of olefins with H2O2 as the oxidant.Infrared spectra were used to analyze the behavior of the phase transfer of catalyst. In this system, the catalyst not only can act as homogeneous catalyst but also as heterogeneous catalyst to be easily filtered and reused. The epoxidation reaction is clean and exhibits high conversion and selectivity as well as excellent catalyst stability.

  7. Epoxidation catalyst and process

    Science.gov (United States)

    Linic, Suljo; Christopher, Phillip

    2010-10-26

    Disclosed herein is a catalytic method of converting alkenes to epoxides. This method generally includes reacting alkenes with oxygen in the presence of a specific silver catalyst under conditions suitable to produce a yield of the epoxides. The specific silver catalyst is a silver nanocrystal having a plurality of surface planes, a substantial portion of which is defined by Miller indices of (100). The reaction is performed by charging a suitable reactor with this silver catalyst and then feeding the reactants to the reactor under conditions to carry out the reaction. The reaction may be performed in batch, or as a continuous process that employs a recycle of any unreacted alkenes. The specific silver catalyst has unexpectedly high selectivity for epoxide products. Consequently, this general method (and its various embodiments) will result in extraordinarily high epoxide yields heretofore unattainable.

  8. 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

  9. Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride-Molecular Ni Catalyst System.

    Science.gov (United States)

    Kasap, Hatice; Caputo, Christine A; Martindale, Benjamin C M; Godin, Robert; Lau, Vincent Wing-Hei; Lotsch, Bettina V; Durrant, James R; Reisner, Erwin

    2016-07-27

    Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride ((NCN)CNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The (NCN)CNx-NiP system showed an activity of 763 μmol (g CNx)(-1) h(-1) toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h(-1), and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of (NCN)CNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited (NCN)CNx in the presence of an organic substrate can accumulate ultralong-lived "trapped electrons", which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel.

  10. New Catalysts for ROMP

    Institute of Scientific and Technical Information of China (English)

    H. Berke; C. Frech; A. Lhamazares; O. Blacque; H.W. Schmalle; C. Adlhart; P. Chen

    2005-01-01

    @@ 1Introduction Ring Opening Metathesis Polymerization (ROMP) is based on the olefin metathesis reaction, which requires transition metal catalysts. Mainly molybdenum, tungsten and ruthenium based catalysts have up to now been used. The "in-between" metal rhenium was only rarely applied in olefin metathesis reactions, and not at all in ROMP processes.We have found that cationic phosphine substituted dinitrosyl rhenium complexes[1]1a and 1b effectively catalyze ROMP of norbonene, dicyclopentadiene and of cyclooctene. See Fig. 1.

  11. Catalysts from synthetic genetic polymers.

    Science.gov (United States)

    Taylor, Alexander I; Pinheiro, Vitor B; Smola, Matthew J; Morgunov, Alexey S; Peak-Chew, Sew; Cozens, Christopher; Weeks, Kevin M; Herdewijn, Piet; Holliger, Philipp

    2015-02-19

    The emergence of catalysis in early genetic polymers such as RNA is considered a key transition in the origin of life, pre-dating the appearance of protein enzymes. DNA also demonstrates the capacity to fold into three-dimensional structures and form catalysts in vitro. However, to what degree these natural biopolymers comprise functionally privileged chemical scaffolds for folding or the evolution of catalysis is not known. The ability of synthetic genetic polymers (XNAs) with alternative backbone chemistries not found in nature to fold into defined structures and bind ligands raises the possibility that these too might be capable of forming catalysts (XNAzymes). Here we report the discovery of such XNAzymes, elaborated in four different chemistries (arabino nucleic acids, ANA; 2'-fluoroarabino nucleic acids, FANA; hexitol nucleic acids, HNA; and cyclohexene nucleic acids, CeNA) directly from random XNA oligomer pools, exhibiting in trans RNA endonuclease and ligase activities. We also describe an XNA-XNA ligase metalloenzyme in the FANA framework, establishing catalysis in an entirely synthetic system and enabling the synthesis of FANA oligomers and an active RNA endonuclease FANAzyme from its constituent parts. These results extend catalysis beyond biopolymers and establish technologies for the discovery of catalysts in a wide range of polymer scaffolds not found in nature. Evolution of catalysis independent of any natural polymer has implications for the definition of chemical boundary conditions for the emergence of life on Earth and elsewhere in the Universe.

  12. Characterization of three-way automotive catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kenik, E.A.; More, K.L. [Oak Ridge National Lab., TN (United States); LaBarge, W. [Delphi Automotive Systems, Flint, MI (United States)] [and others

    1997-04-01

    The CRADA between Delphi Automotive Systems (Delphi; formerly General Motors - AC Delco, Systems) and Lockheed Martin Energy Research (LMER) on automotive catalysts was completed at the end of FY96, after a ten month, no-cost extension. The CRADA was aimed at improved performance and lifetime of noble metal based three-way-catalysts (TWC), which are the primary catalytic system for automotive emission control systems. While these TWC can meet the currently required emission standards, higher than optimum noble metal loadings are often required to meet lifetime requirements. In addition, more stringent emission standards will be imposed in the near future, demanding improved performance and service life from these catalysts. Understanding the changes of TWC conversion efficiency with ageing is a critical need in improving these catalysts. Initially in a fresh catalyst, the active material is often distributed on a very fine scale, approaching single atoms or small atomic clusters. As such, a wide range of analytical techniques have been employed to provide high spatial resolution characterization of the evolving state of the catalytic material.

  13. Ni-Based Catalysts for Low Temperature Methane Steam Reforming: Recent Results on Ni-Au and Comparison with Other Bi-Metallic Systems

    Directory of Open Access Journals (Sweden)

    Anna M. Venezia

    2013-06-01

    Full Text Available Steam reforming of light hydrocarbons provides a promising method for hydrogen production. Ni-based catalysts are so far the best and the most commonly used catalysts for steam reforming because of their acceptably high activity and significantly lower cost in comparison with alternative precious metal-based catalysts. However, nickel catalysts are susceptible to deactivation from the deposition of carbon, even when operating at steam-to-carbon ratios predicted to be thermodynamically outside of the carbon-forming regime. Reactivity and deactivation by carbon formation can be tuned by modifying Ni surfaces with a second metal, such as Au through alloy formation. In the present review, we summarize the very recent progress in the design, synthesis, and characterization of supported bimetallic Ni-based catalysts for steam reforming. The progress in the modification of Ni with noble metals (such as Au and Ag is discussed in terms of preparation, characterization and pretreatment methods. Moreover, the comparison with the effects of other metals (such as Sn, Cu, Co, Mo, Fe, Gd and B is addressed. The differences of catalytic activity, thermal stability and carbon species between bimetallic and monometallic Ni-based catalysts are also briefly shown.

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

    OpenAIRE

    Galip Akay

    2016-01-01

    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 s...

  15. A One-Bead-One-Catalyst Approach to Aspartic Acid-Based Oxidation Catalyst Discovery

    Science.gov (United States)

    Lichtor, Phillip A.; Miller, Scott J.

    2011-01-01

    We report an approach to the high-throughput screening of asymmetric oxidation catalysts. The strategy is based on application of the one-bead-one-compound library approach, wherein each of our catalyst candidates is based on a peptide scaffold. For this purpose we rely on a recently developed catalytic cycle that employs an acid-peracid shuttle. In order to implement our approach, we developed a compatible linker and demonstrated that the library format is amenable to screening and sequencing of catalysts employing partial Edman degradation and MALDI mass spectrometry analysis. The system was applied to the discovery (and re-discovery) of catalysts for the enantioselective oxidation of a cyclohexene derivative. The system is now poised for application to unprecedented substrate classes for asymmetric oxidation reactions. PMID:21417485

  16. Stability and resistance of nickel catalysts for hydrodeoxygenation

    DEFF Research Database (Denmark)

    Mortensen, Peter Mølgaard; Gardini, Diego; de Carvalho, Hudson W. P.;

    2014-01-01

    of activity. Analysis of the spent catalyst revealed that the adsorption of chlorine on the catalyst was completely reversible, but chlorine had caused sintering of nickel particles. In two experiments, potassium, as either KCl or KNO3, was impregnated on the catalyst prior to testing. In both cases......The long term stability and resistance toward carbon deposition, sulfur, chlorine, and potassium of Ni/ZrO2 as a catalyst for the hydrodeoxygenation (HDO) of guaiacol in 1-octanol (as a model compound system for bio-oil) has been investigated at 250 degrees C and 100 bar in a trickle bed reactor...... setup. Without impurities in the feed good stability of the Ni/ZrO2 catalyst could be achieved over more than 100 h of operation, particularly for a sample prepared with small Ni particles, which minimized carbon deposition. Exposing the catalyst to 0.05 wt% sulfur in the feed resulted in rapid...

  17. High-quality bio-oil from one-pot catalytic hydrocracking of kraft lignin over supported noble metal catalysts in isopropanol system.

    Science.gov (United States)

    Yang, Jing; Zhao, Liang; Liu, Shaotong; Wang, Yuanyuan; Dai, Liyi

    2016-07-01

    Catalytic hydrocracking of kraft lignin was carried out in isopropanol system and an orthogonal array design (OAD) was employed to optimize the experimental conditions. GC-MS/FID, elemental analysis, GPC and (1)H-(13)C HSQC NMR were carried out for entire investigation of the liquid products. The results indicated that the hydrocracking process was thermally controlled and catalysts showed significant influences on the product distributions. Comparing with Pd/C, Pt/C and Ru/C, Rh/C inhibited the self-condensation of isopropanol and reduced the formation of oxygenic-chain compounds. The excellent catalytic activity for phenols conversion was obtained over Rh/C. The routes of oxygenic-chain compounds formation and phenol conversion were proposed in detail. The least oxygenic-chain compounds formation, the highest phenols conversion (93.4%), the lowest O/C ratio (0.094) and the highest HHV (37.969MJ/kg) provided the possibility of the high quality bio-oil obtained over Rh/C in isopropanol medium.

  18. Ruthenium-Aryloxide Catalysts for Olefin Metathesis

    Science.gov (United States)

    Monfette, Sebastien; Blacquiere, Johanna M.; Conrad, Jay C.; Beach, Nicholas J.; Fogg, Deryn E.

    : Advances in design of ruthenium aryloxide catalysts for olefin metathesis are described. The target complexes are accessible on reaction of RuCl2(NHC)(py)2 (CHPh) (NHC - N-heterocyclic carbene) with electron-deficient, monodentate aryl- oxides, or aryloxides that yield small, rigid chelate rings. The best of these catalysts offer activity comparable to or greater than that of the parent chloride (Grubbs) systems in ring-closing metathesis (RCM). Preliminary studies of the electronic nature of the Ru-X bond suggest that the metal center is more electropositive in the aryloxide complexes than in the Grubbs systems.

  19. CERES AuTomAted job Loading SYSTem (CATALYST): An automated workflow manager for satellite data production

    Science.gov (United States)

    Gleason, J. L.; Hillyer, T. N.; Wilkins, J.

    2012-12-01

    The CERES Science Team integrates data from 5 CERES instruments onboard the Terra, Aqua and NPP missions. The processing chain fuses CERES observations with data from 19 other unique sources. The addition of CERES Flight Model 5 (FM5) onboard NPP, coupled with ground processing system upgrades further emphasizes the need for an automated job-submission utility to manage multiple processing streams concurrently. The operator-driven, legacy-processing approach relied on manually staging data from magnetic tape to limited spinning disk attached to a shared memory architecture system. The migration of CERES production code to a distributed, cluster computing environment with approximately one petabyte of spinning disk containing all precursor input data products facilitates the development of a CERES-specific, automated workflow manager. In the cluster environment, I/O is the primary system resource in contention across jobs. Therefore, system load can be maximized with a throttling workload manager. This poster discusses a Java and Perl implementation of an automated job management tool tailored for CERES processing.

  20. Triphasic liquid systems: generation and segregation of catalytically active Pd nanoparticles in an ammonium-based catalyst-philic phase.

    Science.gov (United States)

    Perosa, Alvise; Tundo, Pietro; Selva, Maurizio; Canton, Patrizia

    2006-11-21

    A triphasic liquid system fabricated from isooctane, aqueous base, and trioctylmethylammonium chloride/decanol promoted the formation of Pd-nanoparticles in the size range of 2-4 nm which remained immobilised in the onium phase, catalysed organic reactions, and could be recycled.

  1. MgCl2/Et3N Base System as a New Catalyst for the Synthesis of a-Hydroxyphosphonate

    Institute of Scientific and Technical Information of China (English)

    Tajbakhsh, Mahmood; Khaksar, Samad; Tafazoli, Zahra; Bekhradnia, Ahmadreza

    2012-01-01

    An efficient and simple synthesis of a-hydroxyphosphonates via reaction of aldehydes and ketones with di- methylphosphite in the presence of MgCI2/Et3N base system is reported. The use of readily available and easy to handle reagent MgCI2/Et3N makes this method simple, convenient, and practical.

  2. The Information Ecology of Personal Health Record Systems: Secure Messaging as Catalyst and Its Evolving Impact on Use and Consequences

    Science.gov (United States)

    Nazi, Kim M.

    2012-01-01

    Personal Health Records (PHRs) and PHR systems have been designed as consumer-oriented tools to empower patients and improve health care. Despite significant consumer interest and anticipated benefits, adoption remains low. Understanding the consumer perspective is necessary, but insufficient by itself. Consumer PHR use also has broad implications…

  3. New catalysts for exhaust gas cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Haerkoenen, M. [Kemira Metalkat Oy, Oulu (Finland)

    1996-12-31

    Major challenge for future catalyst systems was to develop thermally more stable washcoats for close coupled operating conditions and for engines operating under high speed and load conditions. To design these future emission systems extensive research and development was undertaken to develop methods to disperse and stabilize the key catalytic materials for operation at much higher temperatures. Second priority was to design catalysts that are more effective under low temperature exhaust conditions and have improved oxygen storage properties in the washcoats. Incorporating new materials and modified preparation technology a new generation of metallic catalyst formulations emerged, those being trimetallic K6 (Pt:Pd:Rh and bimetallic K7) (Pd+Pd:Rh). The target was to combine the best property of Pt:Rh (good NO{sub x} reduction) with that of the good HC oxidation activity of Pd and to ensure that precious metal/support interactions were positively maintained. Both K6 and K7 concepts contain special catalyst structures with optimized washcoat performance which can be brick converter configuration. Improvement in light-off, thermal stability and transient performance with these new catalyst formulations have clearly been shown in both laboratory and vehicle testing. (author) (20 refs.)

  4. Chemical interactions in multimetal/zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Sachtler, W.M.H.

    1992-12-21

    Research is proposed on two groups of zeolite based catalysts that contain two transition elements. In one group both metals are fully reduced, in the other group one element is left as a positive ion; it can act as a chemical anchor'', or as a catalyst promoter for the reduced metal. The objective is to explore the potential of such materials for designing superior catalysts for synthesis and conversion of hydrocarbons and other energy carriers. ENDOR, EXAFS, CO-FTIR and TPD will be used to identify the interaction of Mn[sup 2+] ions with Rh[sub n] particles in the same zeolite cage. EXAFS at the Kedge of Fe and Pd, FTIR and Moessbauer spectroscopy will be used to characterize Fe ions and alloyed Fe atoms in PdFe/NaHY. The catalysts will be probed with CO hydrogenation and conversion of hydrocarbons. Methods Which proved successful in our study of Y supported bimetal systems will be applied to identify the state of Pt and Cu in ZSM-5, a catalyst system holding large promise for NO abatement, even in the presence of oxygen.

  5. Supported organoiridium catalysts for alkane dehydrogenation

    Science.gov (United States)

    Baker, R. Thomas; Sattelberger, Alfred P.; Li, Hongbo

    2013-09-03

    Solid supported organoiridium catalysts, a process for preparing such solid supported organoiridium catalysts, and the use of such solid supported organoiridium catalysts in dehydrogenation reactions of alkanes is provided. The catalysts can be easily recovered and recycled.

  6. MicroChannel Reactors for ISRU Applications Using Nanofabricated Catalysts

    Science.gov (United States)

    Carranza, Susana; Makel, Darby B.; Vander Wal, Randall L.; Berger, Gordon M.; Pushkarev, Vladimir V.

    2006-01-01

    With the new direction of NASA to emphasize the exploration of the Moon, Mars and beyond, quick development and demonstration of efficient systems for In-Situ Resources Utilization (ISRU) is more critical and timely than ever before. Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. This paper presents current development of miniaturized chemical processing systems that combine microchannel reactor design with nanofabricated catalysts. Carbon nanotubes (CNT) are used to produce a nanostructure within microchannel reactors, as support for catalysts. By virtue of their nanoscale dimensions, nanotubes geometrically restrict the catalyst particle size that can be supported upon the tube walls. By confining catalyst particles to sizes smaller than the CNT diameter, a more uniform catalyst particle size distribution may be maintained. The high dispersion permitted by the vast surface area of the nanoscale material serves to retain the integrity of the catalyst by reducing sintering or coalescence. Additionally, catalytic efficiency increases with decreasing catalyst particle size (reflecting higher surface area per unit mass) while chemical reactivity frequently is enhanced at the nanoscale. Particularly significant is the catalyst exposure. Rather than being confined within a porous material or deposited upon a 2-d surface, the catalyst is fully exposed to the reactant gases by virtue of the nanofabricated support structure. The combination of microchannel technology with nanofabricated catalysts provides a synergistic effect, enhancing both technologies with the potential to produce much more efficient systems than either technology alone. The development of highly efficient microchannel reactors will be applicable to multiple ISRU programs. By selection of proper nanofabricated catalysts, the microchannel reactors can be

  7. Combined high-pressure cell-ultrahigh vacuum system for fast testing of model metal alloy catalysts using scanning mass spectrometry

    DEFF Research Database (Denmark)

    Johansson, Martin; Jørgensen, Jan Hoffmann; Chorkendorff, Ib

    2004-01-01

    An apparatus for fabrication, surface analysis in ultrahigh vacuum, and testing of the catalytic activity of model metal alloy catalysts is described. Arrays of model catalysts are produced by electron-beam deposition of up to four metals simultaneously onto a substrate. The surface analysis...... techniques available are scanning electron microscopy, x-ray photoemission spectroscopy, ion scattering spectroscopy, Auger electron spectroscopy, sputter profiling, and temperature programmed desorption. The catalytic activity of the model catalysts is tested individually by scanning a combined gas delivery...... be studied on a substrate 10 mm in diameter. A high pressure cell with an all-metal sealed ultrahigh vacuum lock is also described as part of the work. ©2004 American Institute of Physics....

  8. Mesoporous molecular sieve catalysts

    DEFF Research Database (Denmark)

    Højholt, Karen Thrane

    be used as solid acid catalysts but can also be used as a size-selective matrix. It was shown that it is possible to encapsulate 1-2 nm sized gold nanoparticles by silicalite-1 or ZSM-5 zeolite crystals thereby forming a sintering-stable and substrate size-selective oxidation catalyst. After carrying out...... calcination experiments, both in situ and ex situ indicated that the gold nanoparticles embedded in the crystals were highly stable towards sintering. The catalytic tests proved that the embedded gold nanoparticles were active in selective aldehyde oxidation and were only accessible through the micropores...

  9. Aerogel derived catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, J. G., LLNL

    1996-12-11

    Aerogels area class of colloidal materials which have high surface areas and abundant mesoporous structure. SiO{sub 2} aerogels show unique physical, optical and structural properties. When catalytic metals are incorporated in the aerogel framework, the potential exists for new and very effective catalysts for industrial processes. Three applications of these metal-containing SiO{sub 2} aerogels as catalysts are briefly reviewed in this paper--NO{sub x} reduction, volatile organic compound destruction, and partial oxidation of methane.

  10. Olefin metathesis catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kukes, S.G.; Banks, R.L.

    1986-05-20

    A process is described for preparing a disproportionation catalyst comprising admixing a catalytically effective amount of a calcined and activated catalyst consisting essentially of at least one metal oxide selected from molybdenum oxide and tungsten oxide and a support containing a major proportion of silica or alumina with a promoting amount of a methylating agent selected from the group consisting of dimethyl sulfate, dimethylsulfoxide, trimethyloxonium tetrafluorborate, methyl iodide, and methyl bromide, and subjecting same to inert atmospheric conditions for the methylating agent to promote the activity of the calcined molybdenum and tungsten oxides for the disproportionation of olefins.

  11. Efficient electrochemical water oxidation in neutral and near-neutral systems with a nanoscale silver-oxide catalyst.

    Science.gov (United States)

    Joya, Khurram S; Ahmad, Zahoor; Joya, Yasir F; Garcia-Esparza, Angel T; de Groot, Huub J M

    2016-08-11

    In electrocatalytic water splitting systems pursuing for renewable energy using sunlight, developing robust, stable and easily accessible materials operating under mild chemical conditions is pivotal. We present here a unique nanoparticulate type silver-oxide (AgOx-NP) based robust and highly stable electrocatalyst for efficient water oxidation. The AgOx-NP is generated in situ in a HCO3(-)/CO2 system under benign conditions. Micrographs show that they exhibit a nanoscale box type squared nano-bipyramidal configuration. The oxygen generation is initiated at low overpotential, and a sustained O2 evolution current density of >1.1 mA cm(-2) is achieved during prolonged-period water electrolysis. The AgOx-NP electrocatalyst performs exceptionally well in metal-ion free neutral or near-neutral carbonate, phosphate and borate buffers relative to recently reported Co-oxide and Ni-oxide based heterogeneous electrocatalysts, which are unstable in metal-ion free electrolytes and tend to deactivate with time and lose catalytic performance during long-term experimental tests.

  12. Efficient electrochemical water oxidation in neutral and near-neutral systems by nanoscale silver-oxide catalyst

    KAUST Repository

    Joya, Khurram

    2016-07-19

    In electrocatalytic water splitting systems pursuing for renewable energy using sun light, developing robust, stable and easy accessible materials operating under mild chemical conditions is pivotal. We present here unique nano-particulate type silver-oxide (AgOx-NP) based robust and highly stable electrocatalyst for efficient water oxidation. The AgOx-NP is generated in situ in a HCO3–/CO2 system under benign conditions. Mircographs show that they exhibit nanoscale box type squared nano-bipyramidal configuration. The oxygen generation is initiated at low overpotential, and a sustained O2 evolution current density of > 1.1 mA cm–2 is achieved during prolonged-period water electrolysis. The AgOx-NP electrocatalyst performs exceptionally well in metal-ions free neutral or near-neutral carbonate, phosphate and borate buffers relative to recently reported Co-oxide and Ni-oxide based heterogeneous electrocatalysts, which are unstable in metal-ions free electrolyte and tend to degrade with time and lose catalytic performance during long-term experimental tests.

  13. Study and Commercial Application of Graded Optimization of Catalysts for Fixed Bed Residue Upgrading Unit

    Institute of Scientific and Technical Information of China (English)

    Han Zhaoming; Jiang Lijing

    2007-01-01

    The SHIFT-G technology of inverse catalyst loading is used to optimize the catalyst grading in the residue hydrotreating unit.The results,taken from pilot tests and commercial units,have showed that the optimized catalyst grading system can reasonably distribute the reaction load,effectively improve the properties of hydrotreated products,prolong the operating cycle and promote economic benefits.

  14. Plasmonic Ag-pillared rectorite as catalyst for degradation of 2,4-DCP in the H{sub 2}O{sub 2}-containing system under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yunfang [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Fang, Jianzhang, E-mail: fangjzh@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China); Lu, Shaoyou [Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China); Wu, Yan; Chen, Dazhi; Huang, Liyan [Institute of Engineering Technology of Guangdong Province, Key Laboratory of Water Environmental Pollution Control of Guangdong Province, Guangzhou 510440 (China); Cheng, Cong; Ren, Lu; Zhu, Ximiao [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Fang, Zhanqiang [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China)

    2015-10-30

    Highlights: • The Ag-R catalyst was synthesized via a novel thermal decomposition method. • Ag-R catalyst possessed the synergistic effects of SPR and adsorption capacity. • The degradation of 2,4-DCP was evaluated in Ag-R/H{sub 2}O{sub 2}/visible light system. - Abstract: This study aims at photocatalytic degradation of 2,4-DCP with the assistance of H{sub 2}O{sub 2} in aqueous solution by a composite catalyst of Ag-rectorite. The catalysts were prepared via a novel thermal decomposition method followed after the cation-exchange process. The synthesized nano-materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface analyzer, Ultraviolet–visible light (UV–vis) absorption spectra, field-emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The different mechanisms of degradation process with or without visible light irradiation were discussed, respectively. Moreover, the degradation efficiency of 2,4-DCP wastewater under Ag-rectorite/H{sub 2}O{sub 2}/visible light system was investigated by series of experiments, concerning on effects of major operation factors, such as H{sub 2}O{sub 2} dosage and the initial pH value. The highest degradation rate was observed when adding 0.18 mL H{sub 2}O{sub 2} into 50 mL 2,4-DCP solution, and the optimal pH value was 4 for the reaction. Afterwards, total organic carbon (TOC) experiments were carried out to evaluate the mineralization ratio of 2,4-DCP.

  15. A general, efficient, and functional-group-tolerant catalyst system for the palladium-catalyzed thioetherification of aryl bromides and iodides.

    Science.gov (United States)

    Fernández-Rodríguez, Manuel A; Hartwig, John F

    2009-02-20

    The cross-coupling reaction of aryl bromides and iodides with aliphatic and aromatic thiols catalyzed by palladium complexes of the bisphosphine ligand CyPF-tBu (1) is reported. Reactions occur in excellent yields, broad scope, high tolerance of functional groups, and with turnover numbers that exceed those of previous catalysts by 2 or 3 orders of magnitude. These couplings of bromo- and iodoarenes are more efficient than the corresponding reactions of chloroarenes and could be conducted with less catalyst loading and/or milder reaction conditions. Consequently, limitations regarding scope and functional group tolerance previously reported in the coupling of aryl chlorides are now overcome.

  16. Optimization of furfural production from D-xylose with formic acid as catalyst in a reactive extraction system.

    Science.gov (United States)

    Yang, Wandian; Li, Pingli; Bo, Dechen; Chang, Heying; Wang, Xiaowei; Zhu, Tao

    2013-04-01

    Furfural is one of the most promising platform chemicals derived from biomass. In this study, response surface methodology (RSM) was utilized to determine four important parameters including reaction temperature (170-210°C), formic acid concentration (5-25 g/L), o-nitrotoluene volume percentage (20-80 vt.%), and residence time (40-200 min). The maximum furfural yield of 74% and selectivity of 86% were achieved at 190°C for 20 g/L formic acid concentration and 75 vt.% o-nitrotoluene by 75 min. The high boiling solvent, o-nitrotoluene, was recommended as extraction solvent in a reactive extraction system to obtain high furfural yield and reduce furfural-solvent separation costs. Although the addition of halides to the xylose solutions enhanced the furfural yield and selectivity, the concentration of halides was not an important factor on the furfural yield and selectivity.

  17. Gas Phase Polymerization of Ethylene with Supported Titanium-Nickel Catalysts

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new ditransition-metal catalyst system TiCl4-NiCl2/MgCl2-SiO2/AlR3 was prepared.Gas phase polymerization of ethylene with the catalysts has been studied.The kinetic curves of gas phase polymerization showed a decline.The catalystic efficiency and polymerization reaction rates have a optimum value when Ni content of the catalysts was 12.5%(mol).The products obtained are branched polyethylene.

  18. Deactivation-resistant catalyst for selective catalyst reduction of NOx

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to a catalyst for selective catalytic reduction of NOx in alkali metal containing flue gas using ammonia as reductant, the catalyst comprising a surface with catalytically active sites, wherein the surface is at least partly coated with a coating comprising at least...... one metal oxide. In another aspect the present invention relates to the use of said catalyst and to a method of producing said catalyst. In addition, the present invention relates to a method of treating an catalyst for conferring thereon an improved resistance to alkali poisoning....

  19. Protein Scaffolding for Small Molecule Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Baker, David [Univ. of Washington, Seattle, WA (United States)

    2014-09-14

    We aim to design hybrid catalysts for energy production and storage that combine the high specificity, affinity, and tunability of proteins with the potent chemical reactivities of small organometallic molecules. The widely used Rosetta and RosettaDesign methodologies will be extended to model novel protein / small molecule catalysts in which one or many small molecule active centers are supported and coordinated by protein scaffolding. The promise of such hybrid molecular systems will be demonstrated with the nickel-phosphine hydrogenase of DuBois et. al.We will enhance the hydrogenase activity of the catalyst by designing protein scaffolds that incorporate proton relays and systematically modulate the local environment of the catalyticcenter. In collaboration with DuBois and Shaw, the designs will be experimentally synthesized and characterized.

  20. Polypropylene obtained through zeolite supported catalysts

    Directory of Open Access Journals (Sweden)

    Queli C. Bastos

    2004-01-01

    Full Text Available Propylene polymerizations were carried out with f2C(Flu(CpZrCl2 and SiMe2(Ind2ZrCl2 catalysts supported on silica, zeolite sodic mordenite (NaM and acid mordenite (HM. The polymerizations were performed at different temperatures and varying aluminium/zirconium molar ratios ([Al]/[Zr]. The effect of these reaction parameters on the catalyst activity was investigated using a proposed statistical experimental planning. In the case of f2C(Flu(CpZrCl2, SiO2 and NaM were used as support and the catalyst performance evaluated using toluene and pentane as polymerization solvent. The molecular weight, molecular weight distribution, melting point and crystallinity of the polymers were examined. The results indicate very high activities for the syndiospecific heterogeneous system. Also, the polymers obtained had superior Mw and stereoregularity.

  1. Nanopore and nanoparticle catalysts.

    Science.gov (United States)

    Thomas, J M; Raja, R

    2001-01-01

    The design, atomic characterization, performance, and relevance to clean technology of two distinct categories of new nanocatalysts are described and interpreted. Exceptional molecular selectivity and high activity are exhibited by these catalysts. The first category consists of extended, crystallographically ordered inorganic solids possessing nanopores (apertures, cages, and channels), the diameters of which fall in the range of about 0.4 to about 1.5 nm, and the second of discrete bimetallic nanoparticles of diameter 1 to 2 nm, distributed more or less uniformly along the inner walls of mesoporous (ca. 3 to 10 nm diameter) silica supports. Using the principles and practices of solid-state and organometallic chemistry and advanced physico-chemical techniques for in situ and ex situ characterization, a variety of powerful new catalysts has been evolved. Apart from those that, inter alia, simulate the behavior of enzymes in their specificity, shape selectivity, regio-selectivity, and ability to function under ambient conditions, many of these new nanocatalysts are also viable as agents for effecting commercially significant processes in a clean, benign, solvent-free, single-step fashion. In particular, a bifunctional, molecular sieve nanopore catalyst is described that converts cyclohexanone in air and ammonia to its oxime and caprolactam, and a bimetallic nanoparticle catalyst that selectively converts cyclic polyenes into desirable intermediates. Nanocatalysts in the first category are especially effective in facilitating highly selective oxidations in air, and those in the second are well suited to effecting rapid and selective hydrogenations of a range of organic compounds.

  2. Olefin metathesis and catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kukes, S. G.; Banks, R. L.

    1985-05-14

    Olefins are converted into other olefins having different numbers of carbon atoms by contact with a catalyst comprising an inorganic refractory oxide support containing at least one of tungsten oxide and molybdenum oxide and a promoting amount of at least one methylating agent under conditions suitable for the methylating agent compounds to promote the activity of tungsten and molybdenum oxides for the disproportionation reaction.

  3. Deactivation of Oxidation Catalysts

    Science.gov (United States)

    1991-05-01

    Levenspiel (Reference 10) have proposed an equivalent general expression of the form dS _KST (4) dtk to account for deactivation due to catalyst pore...Voorhies, A., IEC, 1954, vol. 37, p. 318. 10. Szepe, S., and 0. Levenspiel , Proc. 4th Europ. Symp. Chem. React. Eng., Pergamon Press, p. 265. 11. U.S

  4. Catalysts for Environmental Remediation

    DEFF Research Database (Denmark)

    Abrams, B. L.; Vesborg, Peter Christian Kjærgaard

    2013-01-01

    The properties of catalysts used in environmental remediation are described here through specific examples in heterogeneous catalysis and photocatalysis. In the area of heterogeneous catalysis, selective catalytic reduction (SCR) of NOx was used as an example reaction with vanadia and tungsta...

  5. Catalytic Destruction of a Surrogate Organic Hazardous Air Pollutant as a Potential Co-benefit for Coal-fired Selective Catalyst Reduction Systems

    Science.gov (United States)

    Catalytic destruction of benzene (C6H6), a surrogate for organic hazardous air pollutants (HAPs) produced from coal combustion, was investigated using a commercial selective catalytic reduction (SCR) catalyst for evaluating the potential co-benefit of the SCR technology for reduc...

  6. Effect of iron-manganese-sepiolite as heterogeneous Fenton-like catalyst on the performance and microbial community of anaerobic granular sludge treatment system.

    Science.gov (United States)

    Su, Chengyuan; Li, Weiguang; Chen, Menglin; Huang, Zhi; Wu, Lei

    2016-01-01

    Both short-term and long-term exposure experiments have been carried out to investigate the influence of iron (Fe)-manganese (Mn)-sepiolite, as a heterogeneous Fenton-like catalyst, on the performance and microbial community of anaerobic granular sludge. During the short-term exposure experiments, chemical oxygen demand (COD) removal efficiency decreased from 73.1% to 64.1% with the presence of 100mg/L of catalyst. However, long-term exposure to the catalyst did not significantly affect the COD removal efficiency (81.8%) as compared to the control (83.5%). Meanwhile, the absorption peaks of coenzyme F420 in extracellular polymeric substances (EPS) of sludge samples were remarkable by excitation-emission matrix (EEM) fluorescence spectra. After long-term exposure, the presence of the catalyst increased secretions of EPS from 83.7mg/g VSS to 89.1mg/g VSS. Further investigations with high throughput sequencing indicated that the abundance of Methanosaeta increased from 57.7% to 70.4% after long-term exposure. In bacterial communities, Proteobacteria, Firmicutes, and Synergistetes were predominant.

  7. PHENANTHROLINE-STABILIZED PALLADIUM NANOPARTICLES IN POLYETHYLENE GLYCOL—AN ACTIVE AND RECYCLABLE CATALYST SYSTEM FOR THE SELECTIVE HYDROGENATION OF OLEFINS USING MOLECULAR HYDROGEN

    Science.gov (United States)

    1,10-Phenanthroline-stabilized palladium nanoparticles dispersed in a polyethylene glycol (PEG) matrix is synthesized which is found to be a stable and active catalyst for the selective hydrogenation of olefins using molecular hydrogen under mild reaction conditions. A variety of...

  8. Synthesis of Arylzinc Thiolates Containing Perfluoroalkyl Chains : Model Catalyst Precursors for the Enantioselective Zinc-Mediated 1,2-Addition of Dialkylzincs to Aldehydes in Fluorous Biphase Systems

    NARCIS (Netherlands)

    Koten, G. van; Kleijn, H.; Rijnberg, E.; Jastrzebski, J.T.B.H.

    1999-01-01

    The synthesis of perfluoroalkyl-functionalized arene trimethylsilyl ethers and their conversion to ethylzinc thiolates is described. These compounds have been successfully applied as catalysts in the enantioselective addition of diethylzinc to benzaldehyde. This is the first example of a two-phase o

  9. Molybdenum sulfide/carbide catalysts

    Science.gov (United States)

    Alonso, Gabriel; Chianelli, Russell R.; Fuentes, Sergio; Torres, Brenda

    2007-05-29

    The present invention provides methods of synthesizing molybdenum disulfide (MoS.sub.2) and carbon-containing molybdenum disulfide (MoS.sub.2-xC.sub.x) catalysts that exhibit improved catalytic activity for hydrotreating reactions involving hydrodesulfurization, hydrodenitrogenation, and hydrogenation. The present invention also concerns the resulting catalysts. Furthermore, the invention concerns the promotion of these catalysts with Co, Ni, Fe, and/or Ru sulfides to create catalysts with greater activity, for hydrotreating reactions, than conventional catalysts such as cobalt molybdate on alumina support.

  10. Testing zinc chloride as a new catalyst for direct synthesis of cellulose di- and tri-acetate in a solvent free system under microwave irradiation.

    Science.gov (United States)

    El Nemr, Ahmed; Ragab, Safaa; El Sikaily, Amany

    2016-10-20

    This research demonstrates the effect of ZnCl2 as a catalyst on the esterification of commercial cotton cellulose using acetic anhydride in order to obtain di- and tri-cellulose acetates under microwave irradiation. It was discovered that microwave irradiation significantly increased the yield and reduced the reaction time. It was found that the maximum yield for cellulose triacetates was 95.83% under the reaction conditions that were as follows: 3min reaction time, 200mg of ZnCl2 catalyst and 20ml of Ac2O for 5g cellulose. However, the cellulose acetate obtained in this manner had the highest DS (2.87). The cellulose di-acetate was produced with the maximum yield of 89.97% and with the highest DS (2.69) using 25ml Ac2O, 200mg of ZnCl2 for 5g cellulose and in 3min reaction time. The effect of some factors such as the amount of used catalyst, the quantity of acetic acid anhydride and the reaction time of the esterification process have been investigated. The production of di- and tri-cellulose acetate and the degree of substitution were confirmed using Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR). The thermal stability was investigated using thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The molecular weight and the degree of polymerization were obtained using Gel Permeation Chromatography (GPC). The analysis confirmed the successful synthesis of di- and tri-cellulose acetate without degradation during the reaction; these results were found to be in contrast to some recent studies. The present study reveals that ZnCl2 is a new catalyst; it is effective as well as inexpensive and is a low toxicity catalyst for usage in cellulose esterification.

  11. Fundamental studies of the mechanism of catalytic reactions with catalysts effective in the gasification of carbon solids and the oxidative coupling of methane. Quarterly report, October 1, 1994--December 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Iglesia, E.; Perry, D.L.; Heinemann, H.

    1994-12-01

    This report describes research on the oxidative coupling of methane and catalysts involved in coal gasification. Topics include methane pyrolysis and catalysts, and magnetic properties of the coal gasification catalyst Ca-Ni-K-O system.

  12. Green heterogeneous Pd(II) catalyst produced from chitosan-cellulose micro beads for green synthesis of biaryls.

    Science.gov (United States)

    Baran, Talat; Sargin, Idris; Kaya, Murat; Menteş, Ayfer

    2016-11-01

    In green catalyst systems, both the catalyst and the technique should be environmentally safe. In this study we designed a green palladium(II) catalyst for microwave-assisted Suzuki CC coupling reactions. The catalyst support was produced from biopolymers; chitosan and cellulose. The catalytic activity of the catalyst was tested on 16 substrates in solvent-free media and compared with those of commercial palladium salts. Reusability tests were done. The catalyst was also used in conventional reflux-heating system to demonstrate the efficiency of microwave heating method. We recorded high activity, selectivity and excellent TONs (6600) and TOFs (82500) just using a small catalyst loading (1.5×10(-3)mol%) in short reaction time (5min). The catalyst exhibited a long lifetime (9 runs). The findings indicated that both green chitosan/cellulose-Pd(II) catalyst and the microwave heating are suitable for synthesis of biaryl compounds by using Suzuki CC coupling reactions.

  13. Magnetic nanoparticles conjugated to chiral imidazolidinone as recoverable catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Mondini, Sara [Consiglio Nazionale delle Ricerche, Laboratorio di Nanotecnologie, Istituto di Scienze e Tecnologie Molecolari (Italy); Puglisi, Alessandra; Benaglia, Maurizio, E-mail: maurizio.benaglia@unimi.it; Ramella, Daniela [Università degli Studi di Milano, Dipartimento di Chimica (Italy); Drago, Carmelo [Consiglio Nazionale delle Ricerche, Istituto di Chimica Biomolecolare (Italy); Ferretti, Anna M.; Ponti, Alessandro, E-mail: alessandro.ponti@istm.cnr.it [Consiglio Nazionale delle Ricerche, Laboratorio di Nanotecnologie, Istituto di Scienze e Tecnologie Molecolari (Italy)

    2013-11-15

    The immobilization of an ad hoc designed chiral imidazolidin-4-one onto iron oxide magnetic nanoparticles (MNPs) is described, to afford MNP-supported MacMillan’s catalyst. Morphological and structural analysis of the materials, during preparation, use, and recycle, has been carried out by transmission electron microscopy. The supported catalyst was tested in the Diels–Alder reaction of cyclopentadiene with cinnamic aldehyde, affording the products in good yields and enantiomeric excesses up to 93 %, comparable to those observed with the non-supported catalyst. Recovery of the chiral catalyst has been successfully performed by simply applying an external magnet to achieve a perfect separation of the MNPs from the reaction product. The recycle of the catalytic system has been also investigated. Noteworthy, this immobilized MacMillan’s catalyst proved to be able to efficiently promote the reaction in pure water.

  14. Catalysts Efficiency Evaluation by using CC Analysis Test

    Directory of Open Access Journals (Sweden)

    Arina Negoitescu

    2011-10-01

    Full Text Available The study emphasizes the necessity of the catalysts efficiency testing. Diagnosis systems using lambda probes are based on the capacity of the catalyst oxygen storage. Comparing the lambda probe signals upstream and downstream of catalyst provides an indication on catalyst activity, although the correlation between oxygen storage capacity and catalyst efficiency is still difficult. Diagnosis for the 1.4 Renault Clio Symbol was accomplished in the Road Vehicles Lab at the Politehnica University of Timisoara using AVL Dicom 4000. The tests showed that the engine worked with lean mixture being necessary a fuel mixture correction calculated by the control unit ECU. A compensation of 0.14 % vol is required for the engine correct operation and emissions integration within permissible limits

  15. Computationally Probing the Performance of Hybrid, Heterogeneous, and Homogeneous Iridium-Based Catalysts for Water Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    García-Melchor, Max [SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford CA (United States); Vilella, Laia [Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST),Tarragona (Spain); Departament de Quimica, Universitat Autonoma de Barcelona, Barcelona (Spain); López, Núria [Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Tarragona (Spain); Vojvodic, Aleksandra [SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park CA (United States)

    2016-04-29

    An attractive strategy to improve the performance of water oxidation catalysts would be to anchor a homogeneous molecular catalyst on a heterogeneous solid surface to create a hybrid catalyst. The idea of this combined system is to take advantage of the individual properties of each of the two catalyst components. We use Density Functional Theory to determine the stability and activity of a model hybrid water oxidation catalyst consisting of a dimeric Ir complex attached on the IrO2(110) surface through two oxygen atoms. We find that homogeneous catalysts can be bound to its matrix oxide without losing significant activity. Hence, designing hybrid systems that benefit from both the high tunability of activity of homogeneous catalysts and the stability of heterogeneous systems seems feasible.

  16. SCALEUP OF ALUMINUM PHOSPHATE CATALYST FOR PILOT PLANT LPDMEtm RUN

    Energy Technology Data Exchange (ETDEWEB)

    Andrew W. Wang

    2002-01-01

    The Liquid Phase Dimethyl Ether (LPDME{trademark}) process converts synthesis gas to dimethyl ether in a single slurry bubble column reactor. A mixed slurry of methanol synthesis catalyst and methanol dehydration catalyst in a neutral mineral oil simultaneously synthesizes methanol from syngas and converts some of it to dimethyl ether and water. The reaction scheme is shown below: 2H{sub 2} + CO = CH{sub 3}OH; 2CH{sub 3}OH = CH{sub 3}OCH{sub 3} + H{sub 2}O; H{sub 2}O + CO = CO{sub 2} + H{sub 2}. Most of the water produced in this reaction is converted to hydrogen by reduction with carbon monoxide (water gas shift reaction). This synergy permits higher per pass conversion than methanol synthesis alone. The enhancement in conversion occurs because dehydration of the methanol circumvents the equilibrium constraint of the syngas-to-methanol step. The slurry bubble column reactor provides the necessary heat transfer capacity to handle the greater heat duty associated with high conversion. In order to improve the stability of the catalyst system, non-stoichiometric aluminum phosphate was proposed as the dehydration catalyst for the LPDME{trademark} process. This aluminum phosphate material is a proprietary catalyst. This catalyst system of a standard methanol catalyst and the aluminum phosphate provided stable process performance that met the program targets under our standard test process conditions in the laboratory. These targets are (1) an initial methanol equivalent productivity of 28 gmol/kg/hr, (2) a CO{sub 2}-free, carbon selectivity of 80% to dimethyl ether and (3) stability of both catalysts equivalent to that of the methanol catalyst in the absence of the aluminum phosphate. A pilot plant trial of the LPDME{trademark} process using the aluminum phosphate catalyst was originally planned for March 1998 at the DOE-owned, Air Products (APCI)-operated facility at LaPorte, Texas. Because the aluminum phosphate catalyst is not commercially available, we initiated a

  17. SCALEUP OF ALUMINUM PHOSPHATE CATALYST FOR PILOT PLANT LPDMEtm RUN

    Energy Technology Data Exchange (ETDEWEB)

    Andrew W. Wang

    2002-05-15

    The Liquid Phase Dimethyl Ether (LPDME{trademark}) process converts synthesis gas to dimethyl ether in a single slurry bubble column reactor. A mixed slurry of methanol synthesis catalyst and methanol dehydration catalyst in a neutral mineral oil simultaneously synthesizes methanol from syngas and converts some of it to dimethyl ether and water. The reaction scheme is: 2H{sub 2} + CO = CH{sub 3}OH 2CH{sub 3}OH = CH{sub 3}OCH{sub 3} + H{sub 2}O H{sub 2}O + CO = CO{sub 2} + H{sub 2}. Most of the water produced in this reaction is converted to hydrogen by reduction with carbon monoxide (water gas shift reaction). This synergy permits higher per pass conversion than methanol synthesis alone. The enhancement in conversion occurs because dehydration of the methanol circumvents the equilibrium constraint of the syngas-to-methanol step. The slurry bubble column reactor provides the necessary heat transfer capacity to handle the greater heat duty associated with high conversion. In order to improve the stability of the catalyst system, non-stoichiometric aluminum phosphate was proposed as the dehydration catalyst for the LPDME{trademark} process. This aluminum phosphate material is a proprietary catalyst. This catalyst system of a standard methanol catalyst and the aluminum phosphate provided stable process performance that met the program targets under our standard test process conditions in the laboratory. These targets are (1) an initial methanol equivalent productivity of 28 gmol/kg/hr, (2) a CO{sub 2}-free, carbon selectivity of 80% to dimethyl ether and (3) stability of both catalysts equivalent to that of the methanol catalyst in the absence of the aluminum phosphate. A pilot plant trial of the LPDME{trademark} process using the aluminum phosphate catalyst was originally planned for March 1998 at the DOE-owned, Air Products (APCI)-operated facility at LaPorte, Texas. Because the aluminum phosphate catalyst is not commercially available, we initiated a scaleup project

  18. Studies on PEM Fuel Cell Noble Metal Catalyst Dissolution

    DEFF Research Database (Denmark)

    Ma, Shuang; Skou, Eivind Morten

    Incredibly vast advance has been achieved in fuel cell technology regarding to catalyst efficiency, improvement of electrolyte conductivity and optimization of cell system. With breathtakingly accelerating progress, Proton Exchange Membrane Fuel Cells (PEMFC) is the most promising and most widely...

  19. Fluorination process using catalysts

    Science.gov (United States)

    Hochel, R.C.; Saturday, K.A.

    1983-08-25

    A process is given for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/, AgF/sub 2/ and NiF/sub 2/, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/ and AgF/sub 2/, whereby the fluorination is significantly enhanced.

  20. Fluorination process using catalyst

    Science.gov (United States)

    Hochel, Robert C.; Saturday, Kathy A.

    1985-01-01

    A process for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3, AgF.sub.2 and NiF.sub.2, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3 and AgF.sub.2, whereby the fluorination is significantly enhanced.

  1. Photo catalyst; Ko shokubai

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    While titanium oxide is excited by the light, electrons of titanium oxide are taken away by the light energy to form positive holes. Water will be decomposed into hydrogen ion and hydroxy radical (OH) by these positive holes. This hydroxy radical is a strong reactive substance called active oxygen, it decomposes organisms. Besides this photo- catalyst function, the titanium oxide can also make surface of a substance superhydrophilic. The super hydrophilicity results in not forming water drops on the glass surface but spreading all over the surface to prevent a covering of fog on the glass surface. The published patents concerning the photo catalysts were 593 from Jan. 1998 to Jan. 1999. The applicant order is the first TOTO 143, the second Daikin Industry 19, the third Toshiba Raitech, Nitto Denko, Hitachi 17 respectively. (NEDO)

  2. Biomass Conversion over Heteropoly Acid Catalysts

    KAUST Repository

    Zhang, Jizhe

    2015-04-01

    Biomass is a natural resource that is both abundant and sustainable. Its efficient utilization has long been the focus of research and development efforts with the aim to substitute it for fossil-based feedstock. In addition to the production of biofuels (e.g., ethanol) from biomass, which has been to some degree successful, its conversion to high value-added chemicals is equally important. Among various biomass conversion pathways, catalytic conversion is usually preferred, as it provides a cost-effective and eco-benign route to the desired products with high selectivities. The research of this thesis is focused on the conversion of biomass to various chemicals of commercial interest by selective catalytic oxidation. Molecular oxygen is chosen as the oxidant considering its low cost and environment friendly features in comparison with commonly used hydrogen peroxide. However, the activation of molecular oxygen usually requires high reaction temperatures, leading to over oxidation and thus lower selectivities. Therefore, it is highly desirable to develop effective catalysts for such conversion systems. We use kegging-type heteropoly acids (HPAs) as a platform for catalysts design because of their high catalytic activities and ease of medication. Using HPA catalysts allows the conversion taking place at relatively low temperature, which is beneficial to saving production cost as well as to improving the reaction selectivity. The strong acidity of HPA promotes the hydrolysis of biomass of giant molecules (e.g. cellulose), which is the first as well as the most difficult step in the conversion process. Under certain circumstances, a HPA combines the merits of homogeneous and heterogeneous catalysts, acting as an efficient homogeneous catalyst during the reaction while being easily separated as a heterogeneous catalyst after the reaction. We have successfully applied HPAs in several biomass conversion systems. Specially, we prepared a HPA-based bi-functional catalyst

  3. Regeneration of LOHC dehydrogenation catalysts: In-situ IR spectroscopy on single crystals, model catalysts, and real catalysts from UHV to near ambient pressure

    Energy Technology Data Exchange (ETDEWEB)

    Amende, Max, E-mail: max.amende@fau.de [Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Kaftan, Andre, E-mail: andre.kaftan@fau.de [Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Bachmann, Philipp, E-mail: philipp.bachmann@fau.de [Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Brehmer, Richard, E-mail: richard.brehmer@fau.de [Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Preuster, Patrick, E-mail: patrick.preuster@fau.de [Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Koch, Marcus, E-mail: marcus.koch@crt.cbi.uni-erlangen.de [Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); and others

    2016-01-01

    Graphical abstract: - Highlights: • We examine the regeneration of Pt-based catalysts poisoned by LOHC degradation. • A microscopic mechanism of the removal of degradation products from Pt is proposed. • Results of our UHV studies on model catalysts are transferred to real catalysis. • Oxidative regeneration of Pt/alumina is possible under mild conditions (600 K). • The degree and temperature regime of regeneration depends on the catalyst morphology. - Abstract: The Liquid Organic Hydrogen Carrier (LOHC) concept offers an efficient route to store hydrogen using organic compounds that are reversibly hydrogenated and dehydrogenated. One important challenge towards application of the LOHC technology at a larger scale is to minimize degradation of Pt-based dehydrogenation catalysts during long-term operation. Herein, we investigate the regeneration of Pt/alumina catalysts poisoned by LOHC degradation. We combine ultrahigh vacuum (UHV) studies on Pt(111), investigations on well-defined Pt/Al{sub 2}O{sub 3} model catalysts, and near-ambient pressure (NAP) measurements on real core–shell Pt/Al{sub 2}O{sub 3} catalyst pellets. The catalysts were purposely poisoned by reaction with the LOHC perhydro-dibenzyltoluene (H18-MSH) and with dicyclohexylmethane (DCHM) as a simpler model compound. We focus on oxidative regeneration under conditions that may be applied in real dehydrogenation reactors. The degree of poisoning and regeneration under oxidative reaction conditions was quantified using CO as a probe molecule and measured by infrared reflection-absorption spectroscopy (IRAS) and diffuse reflectance Fourier transform IR spectroscopy (DRIFTS) for planar model systems and real catalysts, respectively. We find that regeneration strongly depends on the composition of the catalyst surface. While the clean surface of a poisoned Pt(111) single crystal is fully restored upon thermal treatment in oxygen up to 700 K, contaminated Pt/Al{sub 2}O{sub 3} model catalyst and

  4. Olefin metathesis and catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kukes, S. G.; Banks, R. L.

    1985-03-12

    Olefins are converted into other olefins having different numbers of carbon atoms by contact with a catalyst comprising an inorganic refractory material containing at least one of tungsten oxide and molybdenum oxide and a promoting amount of at least one treating agent selected from chlorinated silicon compounds, thionyl chloride, and sulfuryl chloride under conditions suitable for the treating agent to promote the activity of tungsten and molybdenum oxides for the disporoportionation reaction.

  5. 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)

  6. 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.

  7. 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.

  8. Olefin metathesis and side reactions with the binary systems of WCl/sub 6/ and metal alkyls. [Bu/sub 4/Sn, Et/sub 2/Zn, Et/sub 3/Al, BuLi co-catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, K.; Watanabe, O.; Takagi, T.; Fukuzumi, K.

    1976-09-01

    The comparison of the behaviors of the WCl/sub 6/-metal alkyl systems (metal alkyls are Bu/sub 4/Sn, Et/sub 2/Zn, Et/sub 3/Al, and BuLi) was carried out in the metathesis of 2-heptene in benzene. The WCl/sub 6/--Et/sub 2/Zn and the WCl/sub 6/--BuLi systems showed the sharp dependence of metathesis on the co-catalyst/WCl/sub 6/ ratio. The yield of the Friedel--Crafts products, heptylbenzenes, increased with a decrease in the co-catalyst/WCl/sub 6/ and the olefin/WCl/sub 6/ ratios, though the WCl/sub 6/--BuLi system barely catalyzed this side reaction. A proper amount of dicyclopentadiene, phenylacetylene, ethyl ether, ethanol, and esters repressed the Friedel--Crafts reaction, and the metathesis products were obtained in high yield and high selectivity in the metathesis of 2-heptene catalyzed by the WCl/sub 6/--Bu/sub 4/Sn system.

  9. The nanosize catalysts role in the modern hydroprocesses

    Energy Technology Data Exchange (ETDEWEB)

    Irisova, K N; Smirnov, V K; Talisman, E L, E-mail: catachem@mtu-net.ru [Catachem Company Ltd., 20 Narodnaya st., Moscow, 117152 (Russian Federation)

    2011-04-01

    Introduction of the modern technological procedures operating the catalytic systems with different nanosized characteristics is the only way to fabricate components of commercial oils that meet the current requirements. Specifications to the individual catalysts, which form a catalytic system, differ both in nanostructural features of the support porosity and in distribution of nanosized active site. These specifications are related to the purpose of the process and the role of the catalyst in the process.

  10. Novel Brφnsted Acidic Ionic Liquid Based on a Cyclic Guanidinium Cation: a Green, Efficient, and Recyclable Dual Slovent-catalyst System for Fisher Esterification

    Institute of Scientific and Technical Information of China (English)

    GUO Xu; DUAN Hai-feng; SUN Hai; CAO Jun-gang; LIN Ying-jie

    2007-01-01

    A novel Brφnsted acidic ionic liquid(IL) based on the cyclic guanidinium cation has been synthesized. This IL,as a strong Brφnsted acid catalyst or solvent, shows high catalytic activity and biphsaic behavor in the esterifications of carboxylic acids and alcohols. The produced esters as a separate phase can be conveniently decanted out from the IL and the IL is recyclable without any loss of catalytic activity.

  11. Commercializable power source using heterogeneous hydrino catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Mills, R.L.; Akhtar, K.; Zhao, G.; Chang, Z.; He, J.; Hu, X.; Chu, G. [BlackLight Power, Inc., 493 Old Trenton Road, Cranbury, NJ 08512 (United States)

    2010-01-15

    Using Maxwell's equations, the structure of the electron was derived by Mills as a boundary-value problem wherein the electron comprises the source current of time-varying electromagnetic fields during transitions with the constraint that the bound n = 1 state electron cannot radiate energy. A reaction predicted by the solution involves a resonant, nonradiative energy transfer from otherwise stable atomic hydrogen to a catalyst capable of accepting the energy. Specifically, a catalyst comprises a chemical or physical process with an enthalpy change equal to an integer multiple m of the potential energy of atomic hydrogen, 27.2 eV. The product is H (1/p), fractional Rydberg states of atomic hydrogen called ''hydrino atoms'' wherein n=1/2,1/3,1/4,..,1/p (p {<=} 137 is an integer) replaces the well-known parameter n = integer in the Rydberg equation for hydrogen excited states. The reaction step of a nonradiative energy transfer of an integer multiple of 27.2 eV from atomic hydrogen to the catalyst results in an ionized catalyst and free electrons that may cause the reaction to rapidly cease due to charge accumulation. Li, K, and NaH served as the catalysts to form hydrinos at a rapid rate when a high-surface-area conductive support doped with an oxidant was added to speed up the rate limiting step, the removal of electrons from the catalyst as it is ionized by accepting the nonradiative resonant energy transfer from atomic hydrogen to form hydrinos. The concerted electron-acceptor reaction from the catalyst to oxidant via the support was also exothermic to heat the reactants and enhance the rates. Using water-flow, batch calorimetry, the measured power and energy gain from these heterogeneous catalyst systems were up to over 10 W/cm{sup 3} (reactant volume) and a factor of over six times the maximum theoretical, respectively. The reaction scaled linearly to 580 kJ that developed a power of about 30 kW. Solution {sup 1}H NMR on samples

  12. Removal of Disinfection By-Products from Contaminated Water Using a Synthetic Goethite Catalyst via Catalytic Ozonation and a Biofiltration System

    Directory of Open Access Journals (Sweden)

    Yu-Hsiang Wang

    2014-09-01

    Full Text Available The effects of synthetic goethite (α-FeOOH used as the catalyst in catalytic ozonation for the degradation of disinfection by-product (DBP precursors are investigated. A biofiltration column applied following the catalytic ozonation process is used to evaluate the efficiency of removing DBP precursors via biotreatment. Ozone can rapidly react with aromatic compounds and oxidize organic compounds, resulting in a decrease in the fluorescence intensity of dissolved organic matter (DOM. In addition, catalytic ozonation can break down large organic molecules, which causes a blue shift in the emission-excitation matrix spectra. Water treated with catalytic ozonation is composed of low-molecular structures, including soluble microbial products (SMPs and other aromatic proteins (APs. The DOM in SMPs and APs is removed by subsequent biofiltration. Catalytic ozonation has a higher removal efficiency for dissolved organic carbon and higher ultraviolet absorbance at 254 nm compared to those of ozonation without a catalyst. The use of catalytic ozonation and subsequent biofiltration leads to a lower DBP formation potential during chlorination compared to that obtained using ozonation and catalytic ozonation alone. Regarding DBP species during chlorination, the bromine incorporation factor (BIF of trihalomethanes and haloacetic acids increases with increasing catalyst dosage in catalytic ozonation. Moreover, the highest BIF is obtained for catalytic ozonation and subsequent biofiltration.

  13. Decoupling HZSM-5 catalyst activity from deactivation during upgrading of pyrolysis oil vapors.

    Science.gov (United States)

    Wan, Shaolong; Waters, Christopher; Stevens, Adam; Gumidyala, Abhishek; Jentoft, Rolf; Lobban, Lance; Resasco, Daniel; Mallinson, Richard; Crossley, Steven

    2015-02-01

    The independent evaluation of catalyst activity and stability during the catalytic pyrolysis of biomass is challenging because of the nature of the reaction system and rapid catalyst deactivation that force the use of excess catalyst. In this contribution we use a modified pyroprobe system in which pulses of pyrolysis vapors are converted over a series of HZSM-5 catalysts in a separate fixed-bed reactor controlled independently. Both the reactor-bed temperature and the Si/Al ratio of the zeolite are varied to evaluate catalyst activity and deactivation rates independently both on a constant surface area and constant acid site basis. Results show that there is an optimum catalyst-bed temperature for the production of aromatics, above which the production of light gases increases and that of aromatics decrease. Zeolites with lower Si/Al ratios give comparable initial rates for aromatics production, but far more rapid catalyst deactivation rates than those with higher Si/Al ratios.

  14. Routes for deactivation of different autothermal reforming catalysts

    Science.gov (United States)

    Pasel, Joachim; Wohlrab, Sebastian; Kreft, Stefanie; Rotov, Mikhail; Löhken, Katrin; Peters, Ralf; Stolten, Detlef

    2016-09-01

    Fuel cell systems with integrated autothermal reforming units require active and robust catalysts for H2 production. In pursuit of this, an experimental screening of catalysts utilized in the autothermal reforming of commercial diesel fuels is performed. The catalysts incorporate a monolithic cordierite substrate, an oxide support (γ-Al2O3, La-Al2O3, CeO2, Gd-CeO2, ZrO2, Y-ZrO2) and Rh as the active phase. Experiments are run by widely varying the O2/C and H2O/C molar ratios at different gas hourly space velocities. In most cases, this provokes accelerated catalyst deactivation and permits an informative comparison of the catalysts. Fresh and aged catalysts are characterized by temperature-programmed methods, thermogravimetry and transmission electron microscopy to find correlations with catalytic activity and stability. Using this approach, routes for catalyst deactivation are identified, together with causes of different catalytic activities. Suitable reaction conditions can be derived from our results for the operation of reactors for autothermal reforming at steady-state and under transient reaction conditions, which helps improve the efficiency and the stability of fuel cell systems.

  15. 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.

  16. Oxygen-reducing catalyst layer

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Dennis P. (Maplewood, MN); Schmoeckel, Alison K. (Stillwater, MN); Vernstrom, George D. (Cottage Grove, MN); Atanasoski, Radoslav (Edina, MN); Wood, Thomas E. (Stillwater, MN); Yang, Ruizhi (Halifax, CA); Easton, E. Bradley (Halifax, CA); Dahn, Jeffrey R. (Hubley, CA); O' Neill, David G. (Lake Elmo, MN)

    2011-03-22

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  17. Privileged chiral ligands and catalysts

    CERN Document Server

    Zhou, Qi-Lin

    2011-01-01

    This ultimate ""must have"" and long awaited reference for every chemist working in the field of asymmetric catalysis starts with the core structure of the catalysts, explaining why a certain ligand or catalyst is so successful. It describes in detail the history, the basic structural characteristics, and the applications of these ""privileged catalysts"". A novel concept that gives readers a much deeper insight into the topic.

  18. Nano Catalysts for Diesel Engine Emission Remediation

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya Kumar [ORNL; Yang, Xiaofan [ORNL; Debusk, Melanie Moses [ORNL; Mullins, David R [ORNL; Mahurin, Shannon Mark [ORNL; Wu, Zili [ORNL

    2012-06-01

    conditions were provided by our collaborators at John Deere Power Systems. Among various zeolites reported here, CuFe-SSZ-13 offers the best NO{sub x} conversion activity in 150-650 C range and is hydrothermally stable when tested under accelerated aging conditions. It is important to note that Cu-SSZ-13 is now a commercial catalyst for NO{sub x} treatment on diesel passenger vehicles. Thus, our catalyst performs better than the commercial catalyst under fast SCR conditions. We initially focused on fast SCR tests to enable us to screen catalysts rapidly. Only the catalysts that exhibit high NO{sub x} conversion at low temperatures are selected for screening under varying NO{sub 2}:NO{sub x} ratio. The detailed tests of CuFe-SSZ-13 show that CuFe-SSZ-13 is more effective than commercial Cu-SSZ-13 even at NO{sub 2}:NO{sub x} ratio of 0.1. The mechanistic studies, employing stop-flow diffuse reflectance FTIR spectroscopy (DRIFTS), suggest that high concentration of NO{sup +}, generated by heterobimetallic zeolites, is probably responsible for their superior low temperature NO{sub x} activity. The results described in this report clearly show that we have successfully completed the first step in a new emission treatment catalyst which is synthesis and laboratory testing employing simulated exhaust. The next step in the catalyst development is engine testing. Efforts are in progress to obtain follow-on funding to carry out scale-up and engine testing to facilitate commercialization of this technology.

  19. Wafer scale integration of catalyst dots into nonplanar microsystems

    DEFF Research Database (Denmark)

    Gjerde, Kjetil; Kjelstrup-Hansen, Jakob; Gammelgaard, Lauge;

    2007-01-01

    In order to successfully integrate bottom-up fabricated nanostructures such as carbon nanotubes or silicon, germanium, or III-V nanowires into microelectromechanical systems on a wafer scale, reliable ways of integrating catalyst dots are needed. Here, four methods for integrating sub-100-nm...... diameter nickel catalyst dots on a wafer scale are presented and compared. Three of the methods are based on a p-Si layer utilized as an in situ mask, an encapsulating layer, and a sacrificial window mask, respectively. All methods enable precise positioning of nickel catalyst dots at the end...

  20. Poisoning of vanadia based SCR catalysts by potassium:influence of catalyst composition and potassium mobility

    DEFF Research Database (Denmark)

    Olsen, Brian Kjærgaard; Kügler, Frauke; Jensen, Anker Degn

    2016-01-01

    aerosol (mass based distribution mode:1.3 μm) compared to that of the KCl aerosol (mass based distribution mode: 0.12 μm). The relative activities of exposed catalysts indicate that promotion with WO3 accelerates the deactivation, likely due to theenhanced Brønsted acidity which appears to promote...... the transport of potassium. Using a newly developed experimental protocol consisting of two-layer pellets of SCR catalysts, where one side is impregnated with KCl or K2SO4, the potassium transport in such systems, which is assumed to take place through reactionand diffusion over acid sites, was investigated...

  1. REACTOR FILLED WITH CATALYST MATERIAL, AND CATALYST THEREFOR

    NARCIS (Netherlands)

    Sie, S.T.

    1995-01-01

    Abstract of WO 9521691 (A1) Described is a reactor (1) at least partially filled with catalyst granules (11), which is intended for catalytically reacting at least one gas and at least one liquid with each other. According to the invention the catalyst granules (11) are collected in agglomerates

  2. Mechanochemistry, catalysis, and catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Butyagin, P.Yu.

    1987-07-01

    The physical basis of mechanochemistry and the reasons for the initiation and acceleration of chemical reactions upon the mechanical treatment of solids have been considered. The phenomenon of mechanical catalysis has been described in the example case of the oxidation of CO on oxide surfaces, and the nature of the active sites and the laws governing the mechanically activated chemisorption of gases on cleavage and friction surfaces of solids have been examined. The possibilities of the use of the methods of mechanochemistry in processes used to prepare catalysts have been analyzed in examples of decomposition reactions of inorganic compounds and solid-phase synthesis.

  3. Using Mechanical Alloying to Create Bimetallic Catalysts for Vapor-Phase Carbon Nanofiber Synthesis

    Directory of Open Access Journals (Sweden)

    Laura Guevara

    2015-10-01

    Full Text Available Carbon nanofibers were generated over bimetallic catalysts in an atmospheric pressure chemical vapor deposition (APCVD reactor. Catalyst compositions of Fe 30 at%, Cu and Ni 30 at% and Cu were mechanically alloyed using high-energy ball milling over durations of 4, 8, 12, 16, and 20 h. The catalyst powders were then used to produce carbon nanofibers in ethylene and hydrogen (4:1 at temperatures of 500, 550, and 600 °C. The microstructures of the catalysts were characterized as a function of milling time as well as at deposition temperature. The corresponding carbon deposition rates were assessed and are correlated to the microstructural features of each catalyst. The milling process directly determines the performance of each catalyst toward carbon deposition, and both catalysts performed comparably to those made by traditional co-precipitation methods. Considerations in miscible and immiscible nanostructured alloy systems are discussed.

  4. Synthesis,characterization and hydrodesulfurization activity of silica-dispersed NiMoW trimetallic catalysts

    Institute of Scientific and Technical Information of China (English)

    Di Liu; Lihua Liu; Guangci Li; Chenguang Liu

    2010-01-01

    Silica-dispersed NiMoW trimetallic hydrodesulfurization catalysts were prepared by deposition-precipitation method.For comparative purposes,bulk NiMoW trimetallic catalysts were obtained by co-precipitation.Silica was employed to disperse active metals for full utilization of active components and silica-dispersed NiMoW catalyst had high active metal content.BET analysis showed that silica-dispersed NiMoW trimetallic catalysts had a high surface area(165.1 m2/g)and pore volume(0.27 ml/g).Transmission electron microscopy results proved that active components were well dispersed.Hydrodesulfurization activity of silica-dispersed NiMoW catalysts was much higher than that of comparative catalysts and up to twice greater than those of commercial NiMo alumina-supported systems per gram of catalyst.

  5. Aqueous phase reforming of glycerol over Ni-based catalysts for hydrogen production.

    Science.gov (United States)

    Cho, Su Hyun; Moon, Dong Ju

    2011-08-01

    Aqueous phase reforming of glycerol over Ni-based catalysts for hydrogen production was carried out at 225 degrees C, 23 bar and LHSV = 4 h(-1). The Ni-based catalyst was prepared by an incipient wetness impregnation method. The catalysts before and after the reaction were characterized by N2 physisorption, CO chemisorption, XRD, TPR, SEM and TEM techniques. It was found that Ni(20 wt%)-Co(3 wt%)/gamma-Al2O3 catalyst showed higher glycerol conversion and hydrogen selectivity than Ni(20 wt%)/gamma-Al2O3 catalyst. There are no major changes in Ni particles after the reaction over Ni-Co/gamma-Al2O3 catalyst. The results suggest that the Ni-Co/gamma-Al2O3 catalyst can be applied to the hydrogen production system using APR of glycerol.

  6. Ultrasound-assisted phase-transfer catalysis: benzoylation of sodium 4-acetylphenoxide by dual-site phase-transfer catalyst in a tri-liquid system.

    Science.gov (United States)

    Yang, Hung-Ming; Chiu, Chun-Cheng

    2011-01-01

    A novel dual-site phase-transfer catalyst (PTC) was prepared and used to conduct the benzoylation of sodium 4-acetylphenoxide by ultrasound-assisted third-liquid phase-transfer catalysis. The catalyst 1,4-bis(tributylammoniomethyl)benzene dibromide (BTBAMBB) was synthesized from the reaction of p-xylylene dibromide and tributylamine in toluene at 70°C. The dual-site PTC was employed to form the third-liquid phase by extra addition of 0.04-0.05 mol of NaCl into 10 cm(3) of water. In the condition of 0.0425 mol of NaCl at 30°C, the catalytic intermediate in the third-liquid phase reached a maximum value. Almost 80% of the catalyst was transferred from the aqueous phase into the third-liquid phase. The distributions of the catalytic intermediate and dual-site PTC between phases and the kinetics of benzoylation of sodium 4-acetylphenoxide catalyzed by BTBAMBB with ultrasound irradiation were performed. The pseudo-first-order kinetic equation was applied to describe the overall reaction. Under ultrasound irradiation (28 kHz/300 W) in a batch reactor, the yield of product 4-acetylphenyl benzoate in the organic phase was 98.1% in 2 min at 30°C and 250 rpm with the apparent rate constant k(app) to be 0.0075 s(-1), which was 6 times faster than that without using ultrasound (yield=14.4%, k(app)=0.0013 s(-1)). The present study provides a green method to synthesize esters by ultrasound-assisted third-liquid phase-transfer catalysis.

  7. In-situ characterization of heterogeneous catalysts

    CERN Document Server

    Rodriguez, Jose A; Chupas, Peter J

    2013-01-01

    Helps researchers develop new catalysts for sustainable fuel and chemical production Reviewing the latest developments in the field, this book explores the in-situ characterization of heterogeneous catalysts, enabling readers to take full advantage of the sophisticated techniques used to study heterogeneous catalysts and reaction mechanisms. In using these techniques, readers can learn to improve the selectivity and the performance of catalysts and how to prepare catalysts as efficiently as possible, with minimum waste. In-situ Characterization of Heterogeneous Catalysts feat

  8. The generation of efficient supported (Heterogeneous) olefin metathesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grubbs, Robert H

    2013-04-05

    Over the past decade, a new family of homogeneous metathesis catalysts has been developed that will tolerate most organic functionalities as well as water and air. These homogeneous catalysts are finding numerous applications in the pharmaceutical industry as well as in the production of functional polymers. In addition the catalysts are being used to convert seed oils into products that can substitute for those that are now made from petroleum products. Seed oils are unsaturated, contain double bonds, and are a ready source of linear hydrocarbon fragments that are specifically functionalized. To increase the number of applications in the area of biomaterial conversion to petrol chemicals, the activity and efficiency of the catalysts need to be as high as possible. The higher the efficiency of the catalysts, the lower the cost of the conversion and a larger number of practical applications become available. Active supported catalysts were prepared and tested in the conversion of seed oils and other important starting materials. The outcome of the work was successful and the technology has been transferred to a commercial operation to develop viable applications of the discovered systems. A biorefinery that converts seed oils is under construction in Indonesia. The catalysts developed in this study will be considered for the next generation of operations.

  9. Electrochemical Catalyst-Support Effects and Their Stabilizing Role for IrOx Nanoparticle Catalysts during the Oxygen Evolution Reaction.

    Science.gov (United States)

    Oh, Hyung-Suk; Nong, Hong Nhan; Reier, Tobias; Bergmann, Arno; Gliech, Manuel; Ferreira de Araújo, Jorge; Willinger, Elena; Schlögl, Robert; Teschner, Detre; Strasser, Peter

    2016-09-28

    Redox-active support materials can help reduce the noble-metal loading of a solid chemical catalyst while offering electronic catalyst-support interactions beneficial for catalyst durability. This is well known in heterogeneous gas-phase catalysis but much less discussed for electrocatalysis at electrified liquid-solid interfaces. Here, we demonstrate experimental evidence for electronic catalyst-support interactions in electrochemical environments and study their role and contribution to the corrosion stability of catalyst/support couples. Electrochemically oxidized Ir oxide nanoparticles, supported on high surface area carbons and oxides, were selected as model catalyst/support systems for the electrocatalytic oxygen evolution reaction (OER). First, the electronic, chemical, and structural state of the catalyst/support couple was compared using XANES, EXAFS, TEM, and depth-resolved XPS. While carbon-supported oxidized Ir particle showed exclusively the redox state (+4), the Ir/IrOx/ATO system exhibited evidence of metal/metal-oxide support interactions (MMOSI) that stabilized the metal particles on antimony-doped tin oxide (ATO) in sustained lower Ir oxidation states (Ir(3.2+)). At the same time, the growth of higher valent Ir oxide layers that compromise catalyst stability was suppressed. Then the electrochemical stability and the charge-transfer kinetics of the electrocatalysts were evaluated under constant current and constant potential conditions, where the analysis of the metal dissolution confirmed that the ATO support mitigates Ir(z+) dissolution thanks to a stronger MMOSI effect. Our findings raise the possibility that MMOSI effects in electrochemistry-largely neglected in the past-may be more important for a detailed understanding of the durability of oxide-supported nanoparticle OER catalysts than previously thought.

  10. Post-functionalized Hybrid Materials as Multi-site Catalysts

    OpenAIRE

    Rasero Almansa, Antonia María

    2016-01-01

    [EN] Catalysis is one of the fundamental pillars of green chemistry, which was described as the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. The design and application of new catalysts and catalytic systems lead to the dual goals of environmental protection and economic benefit. Heterogeneous catalysts are the most used in industry because they present several advantages such as easy post reaction separation, high stability...

  11. Synthesis of PET and Its Copolymer with Rare Earth Catalysts

    Institute of Scientific and Technical Information of China (English)

    张天骄; 武荣瑞

    2003-01-01

    A new catalyst system was used in the synthesis of polyethylene terephthalate(PET) and its copolymers, which involved a Ln3+ containing compound. The catalytic effects were studied, and it was found that the direct esterification reaction of terephthalate acid(TPA) with ethylene glycol(EG) can be accelerated by the addition of Ln3+ containing compound, which acts as a promoter of the catalyst Sb2O3 in polycondensation of bis hydroxyethyl terephthalate(BHET).

  12. Catalyst design for biorefining.

    Science.gov (United States)

    Wilson, Karen; Lee, Adam F

    2016-02-28

    The quest for sustainable resources to meet the demands of a rapidly rising global population while mitigating the risks of rising CO2 emissions and associated climate change, represents a grand challenge for humanity. Biomass offers the most readily implemented and low-cost solution for sustainable transportation fuels, and the only non-petroleum route to organic molecules for the manufacture of bulk, fine and speciality chemicals and polymers. To be considered truly sustainable, biomass must be derived from resources which do not compete with agricultural land use for food production, or compromise the environment (e.g. via deforestation). Potential feedstocks include waste lignocellulosic or oil-based materials derived from plant or aquatic sources, with the so-called biorefinery concept offering the co-production of biofuels, platform chemicals and energy; analogous to today's petroleum refineries which deliver both high-volume/low-value (e.g. fuels and commodity chemicals) and low-volume/high-value (e.g. fine/speciality chemicals) products, thereby maximizing biomass valorization. This article addresses the challenges to catalytic biomass processing and highlights recent successes in the rational design of heterogeneous catalysts facilitated by advances in nanotechnology and the synthesis of templated porous materials, as well as the use of tailored catalyst surfaces to generate bifunctional solid acid/base materials or tune hydrophobicity.

  13. Latent catalyst; Senzaisei shokubai

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Epoxy resin, an important function material to support such main industries as electric and electronic devices, automobiles, civil engineering, and building construction, is demanded of development of single liquid type resin having excellent quick hardening performance and storage stability. This requirement comes from environmental problems with an intention of saving energies and reducing resin wastes. The Company, using freely its independent phase separation technology that controls molecular structure of catalysts, developed a latent catalyst having excellent storage stability and high-temperature quick hardening performance. Its major features may be summarized as follows: (1) excellent storage stability at room temperature keeping the product stable for 2.5 months or longer (2 days in conventional products); (2) quick hardening performance hardening the resin in seven seconds at 150 degrees C (equivalent to conventional products); and (3) excellent insulation performance of hardened resin at 140 degrees C of 7 times 10 {sup 13} (ohm) (center dot) cm (2 times 10 {sup 12} (ohm) (center dot) cm in conventional products) (translated by NEDO)

  14. Investigation and development of heavy oil upgrading catalysts. 3

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.K.; Lee, I.C.; Yoon, W.L.; Lee, H.T.; Chung, H.; Hwang, Y.J.; Park, S.H. [Korea Inst. of Energy Research, Taejon (Korea, Republic of)

    1995-12-01

    This study aimed at the domestic development of HDS catalysts which are most fundamental and wide-used in the petroleum refinery. In this year, some experimental works were conducted for developing the effective utilization technology of the novel dispersed-catalysts in the hydro-desulfurization of heavy oils, and improving the reaction performance of alumina-supported Mo-based hydro-treating catalysts conventionally used in most of refineries. First, it was experimentally proved that the dispersed catalysts of Co-Mo could be employed for the hydro-desulfurization of a heavy atmospheric residual oil excluding the catalyst deactivation. The utilization of a carbon-expanded reactor in combination with this dispersed catalyst system exhibited an enhanced reaction performance and provided an efficient way for the separation and recovery of the dispersed catalytic component from oils. Second, the tungsten-incorporated WCoMo/{gamma}-Al{sub 2}O{sub 3} catalyst revealed the improved catalytic performance in the various hydro-treating reactions and in the initial deactivation rates for the high pressure hydro-treatment of a heavy oil as compared with the commercial CoMo/{gamma}-Al{sub 2}O{sub 3} catalyst. This new experimental finding for the promoting role of the monomeric WO{sub 3} species in CoMo/{gamma}-Al{sub 2}O{sub 3} catalyst may be generally applicable to the Mo-based alumina-sulfide phase, higher catalytic activity, and more extended service life. (author). 101 refs., 33 figs., 18 tabs.

  15. 球形催化剂气力输送系统研究%Study on Pneumatic Conveying System for Spheroidal Catalyst

    Institute of Scientific and Technical Information of China (English)

    张洁; 刘宏伟; 许浩洋

    2012-01-01

    为实现球形催化剂生产过程物料自动化转序,开展气力输送工业试验,考察不同流速下球形催化剂的破碎率,通过对最佳输送流速下物料输送前后的物化指标及颗粒外观对比表明,球形颗粒的强度和磨损率未降低,颗粒外观及物化性能无变化.%For auto-conveying of the material in spheroidal catalyst production, the pneumatic conveying experiment was implemented to examine the breaking rate of spheroidal catalyst. Comparing material' s physical and chemical data and particle appearance before and after being conveyed at an optimum conveying speed shows that both spheroidal particle strength and breaking rate can keep still, including its appearance and physical and chemical data.

  16. Synthesis and characterization of niobium-promoted cobalt/iron catalysts supported on carbon nanotubes for the hydrogenation of carbon monoxide

    Institute of Scientific and Technical Information of China (English)

    Zahra Gholami; Noor Asmawati Mohd Zabidi; Fatemeh Gholami; Mohammadtaghi Vakili

    2016-01-01

    Bimetallic Co/Fe catalysts supported on carbon nanotubes ( CNTs) were prepared, and niobium ( Nb) was added as promoter to the 70Co:30Fe/CNT catalyst. The physicochemical properties of the catalysts were characterized, and the catalytic performances were analyzed at the same operation conditions (H2:CO (volume ratio)= 2:1, p = 1 MPa, and t = 260℃) in a tubular fixed-bed microreactor system. The addition of Nb to the bimetallic catalyst decreases the average size of the oxide nanoparticles and improves the reducibility of the bimetallic catalyst. Evaluation of the catalyst performance in a Fischer-Tropsch reaction shows that the catalyst results in high selectivity to methane, and the selectivity to C5+ increased slightly in the bimetallic catalyst unlike that in the monometallic catalysts. The addition of 1% Nb to the bimetallic catalyst increases CO conversion and selectivity to C5+. Meanwhile, a decrease in methane selectivity is observed.

  17. Long time experience with deactivation and regeneration of DENOX catalysts and evaluation with the Internet database LEONID; Langzeiterfahrung mit der Deaktivierung und Regeneration von DENOX-Katalysatoren sowie Auswertung mit der Internet-Datenbank LEONID

    Energy Technology Data Exchange (ETDEWEB)

    Brandenstein, J.; Dieckmann, H.J.; Gutberlet, H. [E.ON Engineering GmbH, Gelsenkirchen (Germany)

    2008-07-01

    The paper gives an overview over the long-term catalyst deactivation and the main reasons for catalyst aging. The chemical composition of de-activated catalysts provides information on the optimum catalyst regeneration process. The long-term deactivation behaviour of regenerated catalysts is compared to new catalysts. All characteristic catalyst features are listed in an online 'LEONID'-database, developed by E.ON Engineering. The database provides the basis for long-term catalyst management of all connected SCR systems. (orig.)

  18. Iridium-Doped Ruthenium Oxide Catalyst for Oxygen Evolution

    Science.gov (United States)

    Valdez, Thomas I.; Narayan, Sri R.; Billings, Keith J.

    2011-01-01

    NASA requires a durable and efficient catalyst for the electrolysis of water in a polymer-electrolyte-membrane (PEM) cell. Ruthenium oxide in a slightly reduced form is known to be a very efficient catalyst for the anodic oxidation of water to oxygen, but it degrades rapidly, reducing efficiency. To combat this tendency of ruthenium oxide to change oxidation states, it is combined with iridium, which has a tendency to stabilize ruthenium oxide at oxygen evolution potentials. The novel oxygen evolution catalyst was fabricated under flowing argon in order to allow the iridium to preferentially react with oxygen from the ruthenium oxide, and not oxygen from the environment. Nanoparticulate iridium black and anhydrous ruthenium oxide are weighed out and mixed to 5 18 atomic percent. They are then heat treated at 300 C under flowing argon (in order to create an inert environment) for a minimum of 14 hours. This temperature was chosen because it is approximately the creep temperature of ruthenium oxide, and is below the sintering temperature of both materials. In general, the temperature should always be below the sintering temperature of both materials. The iridium- doped ruthenium oxide catalyst is then fabricated into a PEM-based membrane- electrode assembly (MEA), and then mounted into test cells. The result is an electrolyzer system that can sustain electrolysis at twice the current density, and at the same efficiency as commercial catalysts in the range of 100-200 mA/sq cm. At 200 mA/sq cm, this new system operates at an efficiency of 85 percent, which is 2 percent greater than commercially available catalysts. Testing has shown that this material is as stable as commercially available oxygen evolution catalysts. This means that this new catalyst can be used to regenerate fuel cell systems in space, and as a hydrogen generator on Earth.

  19. Ceramic catalyst materials

    Energy Technology Data Exchange (ETDEWEB)

    Sault, A.G.; Gardner, T.J. [Sandia National Laboratories, Albuquerque, NM (United States); Hanprasopwattanna, A.; Reardon, J.; Datye, A.K. [Univ. of New Mexico, Albuquerque, NM (United States)

    1995-08-01

    Hydrous titanium oxide (HTO) ion-exchange materials show great potential as ceramic catalyst supports due to an inherently high ion-exchange capacity which allows facile loading of catalytically active transition metal ions, and an ability to be cast as thin films on virtually any substrate. By coating titania and HTO materials onto inexpensive, high surface area substrates such as silica and alumina, the economics of using these materials is greatly improved, particularly for the HTO materials, which are substantially more expensive in the bulk form than other oxide supports. In addition, the development of thin film forms of these materials allows the catalytic and mechanical properties of the final catalyst formulation to be separately engineered. In order to fully realize the potential of thin film forms of titania and HTO, improved methods for the deposition and characterization of titania and HTO films on high surface area substrates are being developed. By varying deposition procedures, titania film thickness and substrate coverage can be varied from the submonolayer range to multilayer thicknesses on both silica and alumina. HTO films can also be formed, but the quality and reproducibility of these films is not nearly as good as for pure titania films. The films are characterized using a combination of isopropanol dehydration rate measurements, point of zero charge (PZC) measurements, BET surface area, transmission electron microscopy (TEM), and elemental analysis. In order to assess the effects of changes in film morphology on catalytic activity, the films are being loaded with MoO{sub 3} using either incipient wetness impregnation or ion-exchange of heptamolybdate anions followed by calcining. The MoO{sub 3} is then sulfided to form MOS{sub 2}, and tested for catalytic activity using pyrene hydrogenation and dibenzothiophene (DBT) desulfurization, model reactions that simulate reactions occurring during coal liquefaction.

  20. Development of GREET Catalyst Module

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Cronauer, Donald C. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division

    2014-09-01

    Catalysts are critical inputs for many pathways that convert biomass into biofuels. Energy consumption and greenhouse gas (GHG) emissions during the production of catalysts and chemical inputs influence the life-cycle energy consumption, and GHG emissions of biofuels and need to be considered in biofuel life-cycle analysis (LCA). In this report, we develop energy and material flows for the production of three different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5]) 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. They were selected because they are consumed in existing U.S. Department of Energy (DOE) analyses of biofuel processes. For example, a thermochemical ethanol production pathway (indirect gasification and mixed alcohol synthesis) developed by the National Renewable Energy Laboratory (NREL) uses olivine, DEPG, and tar reforming and alcohol synthesis catalysts (Dutta et al., 2011). ZSM-5 can be used in biofuel production pathways such as catalytic upgrading of sugars into hydrocarbons (Biddy and Jones, 2013). Other uses for these compounds and catalysts are certainly possible. In this report, we document the data sources and methodology we used to develop material and energy flows for the catalysts and compounds in the GREET catalyst module. In Section 2 we focus on compounds used in the model Dutta et al. (2011) developed. In Section 3, we report material and energy flows associated with ZSM-5 production. Finally, in Section 4, we report results.

  1. Manipulating the reactivity of nanoscale catalysts

    DEFF Research Database (Denmark)

    Conradsen, Christian Nagstrup

    . A volcano shaped curve of the activity is found as a function of the copper overlayer thickness. The volcano has an optimum at a copper overlayer thickness of 2 Å corresponding to a coverage of 0.78 ML. The Cu/Ru system is deployed to a real catalyst on a high surface area support. The catalyst also proved...... to the single crystal by sputtering. The defects improve the activity of the single crystal by a factor of 8 for the methanation reaction. CO desorption is studied on both a ruthenium single crystal and on ruthenium nanoparticles. In an collaborative project relating CO desorption, a crossover in CO desorption....... Equally, the desorption profile of a flat ruthenium single crystal can be obtained by annealing a thinfilm of nanoparticles to 900 K for 10 min. In the second project it is found that forming a pseudomorphic overlayer of copper on ruthenium enhances the activity compared to both copper and ruthenium...

  2. Synthesis of Anchored Bimetallic Catalysts via Epitaxy

    Directory of Open Access Journals (Sweden)

    Jiaxin Liu

    2016-06-01

    Full Text Available The development of thermodynamically stable supported bimetallic catalysts for high-temperature reaction is significant and highly desirable but remains a grand challenge. In this work, we report a novel approach that relies on the interaction of metal nanoparticles with the support material to form unique bimetallic nanoparticles, which epitaxially anchor onto the support surface. Such unique nanostructured systems are catalytically active and ultrastable during selected catalytic reactions. In this paper, we describe the synthesis processes of ultrastable PtZn nanoparticles epitaxially anchored onto ZnO nanowires, which primarily consist of {10−10} nanoscale facets. Such anchored PtZn nanoparticles demonstrated good stability during high temperature treatments and selected catalytic reactions. The synthesis approach reported in this work provides a new strategy to develop thermodynamically stable supported bimetallic catalysts.

  3. On-demand Hydrogen Production from Organosilanes at Ambient Temperature Using Heterogeneous Gold Catalysts

    Science.gov (United States)

    Mitsudome, Takato; Urayama, Teppei; Kiyohiro, Taizo; Maeno, Zen; Mizugaki, Tomoo; Jitsukawa, Koichiro; Kaneda, Kiyotomi

    2016-11-01

    An environmentally friendly (“green”), H2-generation system was developed that involved hydrolytic oxidation of inexpensive organosilanes as hydrogen storage materials with newly developed heterogeneous gold nanoparticle catalysts. The gold catalyst functioned well at ambient temperature under aerobic conditions, providing efficient production of pure H2. The newly developed size-selective gold nanoparticle catalysts could be separated easily from the reaction mixture containing organosilanes, allowing an on/off-switchable H2-production by the introduction and removal of the catalyst. This is the first report of an on/off-switchable H2-production system employing hydrolytic oxidation of inexpensive organosilanes without requiring additional energy.

  4. On the Effect of Preparation Methods of PdCe-MOR Catalysts as NOx CH4-SCR System for Natural Gas Vehicles Application

    Directory of Open Access Journals (Sweden)

    Acácio Nobre Mendes

    2015-10-01

    Full Text Available In the present work, the effect of several parameters involved in the preparation of PdCe-HMOR catalysts active for NOx selective catalytic reduction with methane (NOx CH4-SCR was studied. Results show that the catalytic performance of Pd-HMOR is better when palladium is introduced by ion-exchange, namely at room temperature. It was also shown that Pd loading does not influence the formation of cerium species, namely surface Ce4+ (CeO2 species and CeO2 species in interaction with Pd. However, when Ce is introduced before Pd, more surface CeO2 species are stabilized in the support and less CeO2 become in interaction with Pd, which results in a worse NOx CH4-SCR catalytic performance.

  5. Effects of Cu over Pd based catalysts supported on silica or niobia

    Directory of Open Access Journals (Sweden)

    Roma M.N.S.C.

    2000-01-01

    Full Text Available Palladium and palladium-copper catalysts supported on silica and niobia were characterized by H2 chemisorption and H2-O2 titration. Systems over silica were also analyzed by transmission electron microscopy and EXAFS. The metallic dispersion decreased from 20% to 7% when the content of Pd was increased from 0.5wt.-% to 3wt.-% in monometallic catalysts. The addition of 3 wt.-% Cu to obtain Pd-Cu catalysts caused a remarkable capacity loss of hydrogen chemisorption. TPR analysis suggested an interaction between the two metals and EXAFS characterization of the catalyst supported on silica confirmed the formation of Pd-Cu alloy. Pd/Nb2O5 catalysts showed turnover numbers higher than those obtained with the Pd/SiO2 systems in the cyclohexane dehydrogenation. However, the bimetallic catalysts showed very low turnover numbers.

  6. Catalyst support effects on hydrogen spillover

    Science.gov (United States)

    Karim, Waiz; Spreafico, Clelia; Kleibert, Armin; Gobrecht, Jens; Vandevondele, Joost; Ekinci, Yasin; van Bokhoven, Jeroen A.

    2017-01-01

    Hydrogen spillover is the surface migration of activated hydrogen atoms from a metal catalyst particle, on which they are generated, onto the catalyst support. The phenomenon has been much studied and its occurrence on reducible supports such as titanium oxide is established, yet questions remain about whether hydrogen spillover can take place on nonreducible supports such as aluminium oxide. Here we use the enhanced precision of top-down nanofabrication to prepare controlled and precisely tunable model systems that allow us to quantify the efficiency and spatial extent of hydrogen spillover on both reducible and nonreducible supports. We place multiple pairs of iron oxide and platinum nanoparticles on titanium oxide and aluminium oxide supports, varying the distance between the pairs from zero to 45 nanometres with a precision of one nanometre. We then observe the extent of the reduction of the iron oxide particles by hydrogen atoms generated on the platinum using single-particle in situ X-ray absorption spectromicroscopy applied simultaneously to all particle pairs. The data, in conjunction with density functional theory calculations, reveal fast hydrogen spillover on titanium oxide that reduces remote iron oxide nanoparticles via coupled proton-electron transfer. In contrast, spillover on aluminium oxide is mediated by three-coordinated aluminium centres that also interact with water and that give rise to hydrogen mobility competing with hydrogen desorption; this results in hydrogen spillover about ten orders of magnitude slower than on titanium oxide and restricted to very short distances from the platinum particle. We anticipate that these observations will improve our understanding of hydrogen storage and catalytic reactions involving hydrogen, and that our approach to creating and probing model catalyst systems will provide opportunities for studying the origin of synergistic effects in supported catalysts that combine multiple functionalities.

  7. Impeded solid state reactions and transformations in ceramic catalysts supports and catalysts

    Directory of Open Access Journals (Sweden)

    Ernő E. Kiss

    2012-12-01

    Full Text Available Impeded chemical reactions and impeded polymorphous transformation in materials are discussed, as desired effects, for stabilization of ceramic catalyst supports and ceramic based catalysts. This paper gives a short overview about the possibilities of slowing down the aging processes in ceramic catalyst supports and catalysts. Special attention is given to alumina and titania based catalysts.

  8. Catalyst Kinetics Analytical Method Study of Ruthenium

    Institute of Scientific and Technical Information of China (English)

    Kou ming-ze; Zhan hui-ying; Kou zong-yan

    2004-01-01

    Color reactions are used to determine ruthenium utilizing spectrophotometer, but the process need high temperature, long time pyrogenation and miscellaneous extraction and it contaminates the enviroment. As the sensitive degree and simple apparatus of catalyst kinetics analytical method, it was extensively attentcd. The fundmental principle means to determinn a certain chemistry reaction rate accelerated by homogeneous catalyst and determine substantial content using the function of the numerical value of of its and the catalyst concentration. Color acid double azo-reagents (chloro-phosphor group, arsenic group and carboxylic acid group) are sensitive color reagent determining uranium and thorium of lanthanon, but the report is few that it is used to determine ruthenium. Since 1990s, the author studied that the ruthenium was possessed evident catalysis to the fade reaction of oxidant (KIO4, KBrO3) oxidating color acid double azo-reagent in acitidy medium and provided the catalyst kinetics analytical method to determine trace ruthenium.sensitive degree was increased 1 ~2 amount than color reaction. The reaction as:The original concentration of color acid double azo-reagents is A. The instantaneous absorbency after t reaction time is At. In homogeneous catalyst reaction: log(A0/At) = KCRu3+t. Reaction time t is invarible, so log(A0/At) = K' CRu3+t.Color acid double azo-reagents, such as: chlor-azochlorphosphor(CPA-TC),bromic-azochlorphosphor (CPA-TB), DBS-azochlorphosphor(DBS-CPA), DBC-azochlorphosphor (DBC-CPA), DBOK-azochlorpho sphor (DBOK-CPA), p-iodineazochlorphosphor(CPA-PI),p-acetylazochlorphosphor (CPA-PA), azochlorpho sphorⅢ(CPAⅢ), chlor-azoarsenic (TC-AsA),bromic-azoarsenic (TB-AsA), DBS-azoarsenic(DCS-AsA), DCS-azoarsenic(DCS-AsA),azoarsenicⅢ(AsAⅢ), bromicnityrlazoarsenic (DBN-AsA), P-acetylcarboxy lazo-p,P-acetylcarboxylazo, were utilized in catalyst kinetics system. The author obtains the satisfactory results that color acid double azo-rea gents

  9. Physico-Chemical and Structural Properties of DeNOx and SO2 Oxidation Catalysts

    DEFF Research Database (Denmark)

    Masters, Stephen Grenville; Oehlers, Cord; Nielsen, Kurt;

    1996-01-01

    Commercial catalysts for NOx removal and SO2 oxidation and their model systems have been investigated by spectroscopic, thermal, electrochemical and X-ray methods. Structural information on the vanadium complexes and compounds as well as physico-chemical properties for catalyst model systems have...... been obtained. The results are discussed in relation to proposed reaction mechanisms....

  10. New hydrocracking catalysts increase throughput, run length

    Energy Technology Data Exchange (ETDEWEB)

    Huizinga, T. [Shell Internationale Petroleum Mij., The Hague (Netherlands); Theunissen, J.M.H. [Rayong Refinery Co. Ltd., Rayong (Thailand); Minderhoud, H.; Veen, R. van [Koninklijke/Shell-Lab., Amsterdam (Netherlands)

    1995-06-26

    An improved, second-stage hydrocracking catalyst has been developed by combining stabilized Y zeolites with amorphous silica alumina cracking components. A commercial application of this catalyst, along with a new, first-stage zeolitic hydrocracking catalyst, resulted in increased unit throughput and cycle length. The paper discusses the hydrocracking process, first-stage catalysts, second-stage catalysts, hydrogenation process, commercial results, and product properties.

  11. Silica supported Brӧnsted acids as catalyst in organic transformations:A comprehensive review

    Institute of Scientific and Technical Information of China (English)

    Manpreet Kaur; Sahil Sharma; Preet M. S. Bedi

    2015-01-01

    Brӧnsted acid catalysts have been used in a number of organic transformations. To overcome limi‐tations, such as toxicity, volatility, high price and hazardous nature of the conventional methods, the catalysts are adsorbed on silica gel to give the benefits and advantages of ready availability, simple work‐up procedure, long catalytic life, environment‐friendliness, good to excellent yields and recy‐clability. The uses of such catalysts have gained importance worldwide. This article describes some of the important silicated catalysts, namely, heteropolyacids, polyphosphoric acid, perchloric acid, fluoroboric acid, and silicated sulphuric acid. These catalysts have been used in a number of organic reactions to yield compounds that are important in the chemical and pharmaceutical industries. We summarize the beneficial effects of these catalysts and the reports that have been published on them in the past several years. In the present review, the description of the catalysts are introduced followed by a recent research history, and a comparison between the silica supported catalysts and other (polymer) supported catalysts. The article ends up giving the advantages of these catalytic systems over the conventional catalyst.

  12. Biomass processing over gold catalysts

    CERN Document Server

    Simakova, Olga A; Murzin, Dmitry Yu

    2014-01-01

    The book describes the valorization of biomass-derived compounds over gold catalysts. Since biomass is a rich renewable feedstock for diverse platform molecules, including those currently derived from petroleum, the interest in various transformation routes has become intense. Catalytic conversion of biomass is one of the main approaches to improving the economic viability of biorefineries.  In addition, Gold catalysts were found to have outstanding activity and selectivity in many key reactions. This book collects information about transformations of the most promising and important compounds derived from cellulose, hemicelluloses, and woody biomass extractives. Since gold catalysts possess high stability under oxidative conditions, selective oxidation reactions were discussed more thoroughly than other critical reactions such as partial hydrogenation, acetalization, and isomerization. The influence of reaction conditions, the role of the catalyst, and the advantages and disadvantages of using gold are pre...

  13. Organometallic catalysts for primary phosphoric acid fuel cells

    Science.gov (United States)

    Walsh, Fraser

    1987-01-01

    A continuing effort by the U.S. Department of Energy to improve the competitiveness of the phosphoric acid fuel cell by improving cell performance and/or reducing cell cost is discussed. Cathode improvement, both in performance and cost, available through the use of a class of organometallic cathode catalysts, the tetraazaannulenes (TAAs), was investigated. A new mixed catalyst was identified which provides improved cathode performance without the need for the use of a noble metal. This mixed catalyst was tested under load for 1000 hr. in full cell at 160 to 200 C in phosphoric acid H3PO4, and was shown to provide stable performance. The mixed catalyst contains an organometallic to catalyze electroreduction of oxygen to hydrogen peroxide and a metal to catalyze further electroreduction of the hydrogen peroxide to water. Cathodes containing an exemplar mixed catalyst (e.g., Co bisphenyl TAA/Mn) operate at approximately 650 mV vs DHE in 160 C, 85% H3PO4 with oxygen as reactant. In developing this mixed catalyst, a broad spectrum of TAAs were prepared, tested in half-cell and in a rotating ring-disk electrode system. TAAs found to facilitate the production of hydrogen peroxide in electroreduction were shown to be preferred TAAs for use in the mixed catalyst. Manganese (Mn) was identified as a preferred metal because it is capable of catalyzing hydrogen peroxide electroreduction, is lower in cost and is of less strategic importance than platinum, the cathode catalyst normally used in the fuel cell.

  14. The selective hydrogenation of crotonaldehyde over bimetallic catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Schoeb, Ann M. [Iowa State Univ., Ames, IA (United States)

    1997-10-17

    The selective hydrogenation of crotonaldehyde has been investigated over a monometallic Pt/SiO2 catalyst and platinum bimetallic catalysts where the second metal was either silver, copper, or tin. The effects of addition of a second metal to the Pt/SiO2 system on the selectivity to crotyl alcohol were investigated. The Pt-Sn bimetallic catalysts were characterized by hydrogen chemisorption, 1H NMR and microcalorimetry. The Pt-Ag/SiO2 and Pt-Cu/SiO2 catalysts were characterized by hydrogen chemisorption. Pt-Sn/SiO2 catalysts selectively hydrogenated crotonaldehyde to crotyl alcohol and the method of preparation of these catalysts affected the selectivity. The most selective Pt-Sn/SiO2 catalysts for the hydrogenation of crotonaldehyde to crotyl alcohol were those in which the Sn precursor was dissolved in a HCl solution. Sn increased both the rate of formation of butyraldehyde and the rate of formation of crotyl alcohol. The Pt/SiO2, Pt-Ag/SiO2 and Pt-Cu/SiO2 catalysts produced only butyraldehyde. Initial heats of adsorption (~90 kJ/mol) measured using microcalorimetry were not affected by the presence of Sn on Pt. We can conclude that there is no through metal electronic interaction between Pt and Sn at least with respect to hydrogen surface bonds since the Pt and Pt-Sn at least with respect to hydrogen surface bonds since the Pt and Pt-Sn had similar initial heats of adsorption coupled with the invariance of the 1H NMR Knight shift.

  15. Hydroformylation of 1-Hexene over Rh/Nano-Oxide Catalysts

    Directory of Open Access Journals (Sweden)

    Sari Suvanto

    2013-03-01

    Full Text Available The effect of nanostructured supports on the activity of Rh catalysts was studied by comparing the catalytic performance of nano- and bulk-oxide supported Rh/ZnO, Rh/SiO2 and Rh/TiO2 systems in 1-hexene hydroformylation. The highest activity with 100% total conversion and 96% yield of aldehydes was obtained with the Rh/nano-ZnO catalyst. The Rh/nano-ZnO catalyst was found to be more stable and active than the corresponding rhodium catalyst supported on bulk ZnO. The favorable morphology of Rh/nano-ZnO particles led to an increased metal content and an increased number of weak acid sites compared to the bulk ZnO supported catalysts. Both these factors favored the improved catalytic performance. Improvements of catalytic properties were obtained also with the nano-SiO2 and nano-TiO2 supports in comparison with the bulk supports. All of the catalysts were characterized by scanning electron microscope (SEM, inductively coupled plasma mass spectrometry (ICP-MS, BET, powder X-ray diffraction (PXRD and NH3- temperature-programmed desorption (TPD.

  16. Investigation of syngas interactions in alcohol synthesis catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Akundi, M.A.

    1998-04-15

    The primary objectives of the project are to (a) synthesize, by controlled sequential and co-impregnation techniques, three distinct composition metal clusters (consisting of Cu-Co-Cr and Cu-Fe-Zn): rich in copper (Methanol selective), rich in ferromagnetic metal (Co or Fe-Hydrocarbon selective) and intermediate range (mixed alcohol catalysts); (b) investigate the changes in the magnetic character of the systems due to interaction with CO, through Zero-field Nuclear Magnetic Resonance (ZFNMR) study of cobalt and Magnetic character (saturation magnetization and coercive field) analysis of the composite catalyst of Vibrating Sample Magnetometry (VSM); (c) examine the changes in syngas adsorption character of the catalyst as the composition changes, by FTIR Spectroscopic analysis of CO stretching frequencies; (d) determine the nature and size of these intermetallic clusters by Scanning Electron Microscopy (SEM); and (e) perform catalytic runs on selected samples and analyze the correlations between the physical and chemical characteristics. The catalysts chosen have a greater promise for industrial application than the Rh and Mo based catalysts. Several groups preparing catalysts by synthetic routes have reported divergent results for activity and selectivity. Generally the research has followed an empirical path and less effort is devoted to analyze the mechanisms and the scientific basis. The primary intent of this study is to analyze the nature of the intermetallic and gas-metal interactions and examine the correlations to catalytic properties.

  17. States of carbon nanotube supported Mo-based HDS catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Hongyan; Liu, Chenguang; Xu, Yongqiang [Key Laboratory of Catalysis, CNPC, College of Chemistry and Chemical Engineering, University of Petroleum, Dongying 257061 (China); Qiu, Jieshan [Carbon Research Laboratory, Center for Nano Materials and Science, Dalian University of Technology, 158 Zhongshan Road, P. O. Box 49, Dalian 116012 (China); Wei, Fei [Department of Chemical Engineering, Tsinghua University, Being, 100084 (China)

    2007-02-15

    As HDS catalysts, the supported catalysts including oxide state Mo, Co-Mo and sulfide state Mo on carbon nanotube (CNT) were prepared, while the corresponding supported catalysts on {gamma}-Al{sub 2}O{sub 3} were prepared as comparison. Firstly, the dispersion of the active phase and loading capacity of Mo species on CNT was studied by XRD and the reducibility properties of Co-Mo catalysts in oxide state over CNTs were investigated by TPR while the sulfide Co-Mo/CNT catalysts were characterized by XRD and LRS techniques. Secondly, the activity and selectivity of hydrodesulfurization (HDS) of dibenzothiophene with Co-Mo/CNT and Co-Mo/{gamma}-Al{sub 2}O{sub 3} were studied. It has been found that the main active molybdenum species in the oxide state MoO{sub 3}/CNT catalysts were MoO{sub 2}, rather than MoO{sub 3} as generally expected. The maximum loading before formation of the bulk phase was lower than 6%m (calculated in MoO{sub 3}). The TPR studies revealed that that active species in oxide state Co-Mo/CNT catalysts were more easily reduced at relatively lower temperatures in comparison to those in Co-Mo/{gamma}-Al{sub 2}O{sub 3}, indicating that the CNT support promoted the reduction of active species. Among 0-1.0 Co/Mo atomic ratio on Co-Mo/CNT, 0.7 has the highest reducibility. It shows that the Co/Mo atomic ratio has a great effect on the reducibility of active species on CNT and their HDS activities and that the incorporation of cobalt improved the dispersion of molybdenum species on CNT and mobilization. It was also found that re-dispersion could occur during the sulfiding process, resulting in low valence state Mo{sub 3}S{sub 4} and Co-MoS{sub 2.17} active phases. The HDS of DBT showed that Co-Mo/CNT catalysts were more active than Co-Mo/{gamma}-Al{sub 2}O{sub 3} and the hydrogenolysis/hydrogenation selectivity of Co-Mo/CNT catalyst was also much higher than Co-Mo/{gamma}-Al{sub 2}O{sub 3}. For the Co-Mo/CNT catalysis system, the catalyst with Co/Mo atomic

  18. Mechanistic insight into sonochemical biodiesel synthesis using heterogeneous base catalyst.

    Science.gov (United States)

    Choudhury, Hanif A; Chakma, Sankar; Moholkar, Vijayanand S

    2014-01-01

    The beneficial effect of ultrasound on transesterification reaction is well known. Heterogeneous (or solid) catalysts for biodiesel synthesis have merit that they do not contaminate the byproduct of glycerol. In this paper, we have attempted to identify the mechanistic features of ultrasound-enhanced biodiesel synthesis with the base-catalyst of CaO. A statistical design of experiments (Box-Behnken) was used to identify the influence of temperature, alcohol to oil molar ratio and catalyst loading on transesterification yield. The optimum values of these parameters for the highest yield were identified through Response Surface Method (with a quadratic model) and ANOVA. These values are: temperature=62 °C, molar ratio=10:1 and catalyst loading=6 wt.%. The activation energy was determined as 82.3 kJ/mol, which is higher than that for homogeneous catalyzed system (for both acidic and basic catalyst). The experimental results have been analyzed vis-à-vis simulations of cavitation bubble dynamics. Due to 3-phase heterogeneity of the system, the yield was dominated by intrinsic kinetics, and the optimum temperature for the highest yield was close to boiling point of methanol. At this temperature, the influence of cavitation bubbles (in terms of both sonochemical and sonophysical effect) is negligible, and ultrasonic micro-streaming provided necessary convection in the system. The influence of all parameters on the reaction system was found to be strongly inter-dependent.

  19. Light Absorbers and Catalysts for Solar to Fuel Conversion

    Science.gov (United States)

    Kornienko, Nikolay I.

    Increasing fossil fuel consumption and the resulting consequences to the environment has propelled research into means of utilizing alternative, clean energy sources. Solar power is among the most promising of renewable energy sources but must be converted into an energy dense medium such as chemical bonds to render it useful for transport and energy storage. Photoelectrochemistry (PEC), the splitting of water into oxygen and hydrogen fuel or reducing CO 2 to hydrocarbon fuels via sunlight is a promising approach towards this goal. Photoelectrochemical systems are comprised of several components, including light absorbers and catalysts. These parts must all synergistically function in a working device. Therefore, the continual development of each component is crucial for the overall goal. For PEC systems to be practical for large scale use, the must be efficient, stable, and composed of cost effective components. To this end, my work focused on the development of light absorbing and catalyst components of PEC solar to fuel converting systems. In the direction of light absorbers, I focused of utilizing Indium Phosphide (InP) nanowires (NWs) as photocathodes. I first developed synthetic techniques for InP NW solution phase and vapor phase growth. Next, I developed light absorbing photocathodes from my InP NWs towards PEC water splitting cells. I studied cobalt sulfide (CoSx) as an earth abundant catalyst for the reductive hydrogen evolution half reaction. Using in situ spectroscopic techniques, I elucidated the active structure of this catalyst and offered clues to its high activity. In addition to hydrogen evolution catalysts, I established a new generation of earth abundant catalysts for CO2 reduction to CO fuel/chemical feedstock. I first worked with molecularly tunable homogeneous catalysts that exhibited high selectivity for CO2 reduction in non-aqueous media. Next, in order to retain molecular tunability while achieving stability and efficiency in aqueous

  20. Intermediate Ethanol Blends Catalyst Durability Program

    Energy Technology Data Exchange (ETDEWEB)

    West, Brian H; Sluder, Scott; Knoll, Keith; Orban, John; Feng, Jingyu

    2012-02-01

    In the summer of 2007, the U.S. Department of Energy (DOE) initiated a test program to evaluate the potential impacts of intermediate ethanol blends (also known as mid-level blends) on legacy vehicles and other engines. The purpose of the test program was to develop information important to assessing the viability of using intermediate blends as a contributor to meeting national goals for the use of renewable fuels. Through a wide range of experimental activities, DOE is evaluating the effects of E15 and E20 - gasoline blended with 15% and 20% ethanol - on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials. This report provides the results of the catalyst durability study, a substantial part of the overall test program. Results from additional projects will be reported separately. The principal purpose of the catalyst durability study was to investigate the effects of adding up to 20% ethanol to gasoline on the durability of catalysts and other aspects of the emissions control systems of vehicles. Section 1 provides further information about the purpose and context of the study. Section 2 describes the experimental approach for the test program, including vehicle selection, aging and emissions test cycle, fuel selection, and data handling and analysis. Section 3 summarizes the effects of the ethanol blends on emissions and fuel economy of the test vehicles. Section 4 summarizes notable unscheduled maintenance and testing issues experienced during the program. The appendixes provide additional detail about the statistical models used in the analysis, detailed statistical analyses, and detailed vehicle specifications.

  1. Selective catalyst reduction light-off strategy

    Science.gov (United States)

    Gonze, Eugene V [Pinckney, MI

    2011-10-18

    An emissions control system includes a temperature determination module and an emissions control module. The temperature determination module determines a first temperature of a heater element of a diesel particulate filter (DPF) assembly in an exhaust system and determines a second temperature of a catalyst of the DPF assembly. The emissions control module selectively activates the heater element, selectively initiates a predefined combustion process in an engine based upon the first temperature, and selectively starts a reductant injection process based upon the second temperature.

  2. Evaluation of different catalysts and development of a new catalyst for the reduction of CO2 to graphite

    Science.gov (United States)

    Tschekalinskij, Alexander; Schindler, Matthias; Kretschmer, Wolfgang

    2016-02-01

    We present an evaluation of different catalysts, methods and parameters for the catalytic reduction of CO2 for 14C-AMS graphite targets for radiocarbon measurement at the Physical Institute of the University Erlangen-Nuremberg in Germany. Currently 10 μm iron powder is used as a catalyst to reduce carbon dioxide to graphite following our standard protocol. An optimal catalyst should provide a short reduction time, no additional fractionation effects, a good reduction yield, lack sintering and should not contain any amounts of both "dead" and "modern" carbon. Seven purchasable catalysts have been evaluated regarding this criteria. Further, the method using zinc and titanium hydride instead of hydrogen gas and the water-trap has been applied to our system and the effect of the water-trap temperature on the reduction time has been tested. A self-made catalyst was produced using aluminum oxide impregnated with iron nitrate. The results of this study indicate three good catalysts and show the success of the applied methods on standard samples like Ox II and Alfa graphite.

  3. The innovation catalysts.

    Science.gov (United States)

    Martin, Roger L

    2011-06-01

    A few years ago the software development company Intuit realized that it needed a new approach to galvanizing customers. The company's Net Promoter Score was faltering, and customer recommendations of new products were especially disappointing. Intuit decided to hold a two-day, off-site meeting for the company's top 300 managers with a focus on the role of design in innovation. One of the days was dedicated to a program called Design for Delight. The centerpiece of the day was a PowerPoint presentation by Intuit founder Scott Cook, who realized midway through that he was no Steve Jobs: The managers listened dutifully, but there was little energy in the room. By contrast, a subsequent exercise in which the participants worked through a design challenge by creating prototypes, getting feedback, iterating, and refining, had them mesmerized. The eventual result was the creation of a team of nine design-thinking coaches--"innovation catalysts"--from across Intuit who were made available to help any work group create prototypes, run experiments, and learn from customers. The process includes a "painstorm" (to determine the customer's greatest pain point), a "soljam" (to generate and then winnow possible solutions), and a "code-jam" (to write code "good enough" to take to customers within two weeks). Design for Delight has enabled employees throughout Intuit to move from satisfying customers to delighting them.

  4. Hydrocarbon conversion catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hoek, A.; Huizinga, T.; Maxwell, I.E.

    1989-08-15

    This patent describes a process for hydrocracking hydrocarbon oils into products of lower average molecular weight and lower average boiling point. It comprises contacting a hydrocarbon oil at a temperature between 250{sup 0}C and 500{sup 0}C and a pressure up to 300 bar in the presence of hydrogen with a catalyst consisting essentially of a Y zeolite modified to have a unit cell size below 24.35A, a water absorption capacity (at 25{sup 0}C and a rho/rho/sub o/ value of 0.2) of at least 8% by weight of the zeolite and a pore volume of at least 0.25 ml/g wherein between 10% and 60% of the total pore volume is made up of pores having a diameter of at least 8 nm; an alumina binder and at least one hydrogenation component selected from the group consisting of a Group VI metal, a Group VIII metal and mixtures thereof.

  5. Supported Catalysts Useful in Ring-Closing Metathesis, Cross Metathesis, and Ring-Opening Metathesis Polymerization

    Directory of Open Access Journals (Sweden)

    Jakkrit Suriboot

    2016-04-01

    Full Text Available Ruthenium and molybdenum catalysts are widely used in synthesis of both small molecules and macromolecules. While major developments have led to new increasingly active catalysts that have high functional group compatibility and stereoselectivity, catalyst/product separation, catalyst recycling, and/or catalyst residue/product separation remain an issue in some applications of these catalysts. This review highlights some of the history of efforts to address these problems, first discussing the problem in the context of reactions like ring-closing metathesis and cross metathesis catalysis used in the synthesis of low molecular weight compounds. It then discusses in more detail progress in dealing with these issues in ring opening metathesis polymerization chemistry. Such approaches depend on a biphasic solid/liquid or liquid separation and can use either always biphasic or sometimes biphasic systems and approaches to this problem using insoluble inorganic supports, insoluble crosslinked polymeric organic supports, soluble polymeric supports, ionic liquids and fluorous phases are discussed.

  6. Low-Temperature CO Oxidation over a Ternary Oxide Catalyst with High Resistance to Hydrocarbon Inhibition.

    Science.gov (United States)

    Binder, Andrew J; Toops, Todd J; Unocic, Raymond R; Parks, James E; Dai, Sheng

    2015-11-02

    Platinum group metal (PGM) catalysts are the current standard for control of pollutants in automotive exhaust streams. Aside from their high cost, PGM catalysts struggle with CO oxidation at low temperatures (oxide catalyst composed of copper oxide, cobalt oxide, and ceria (dubbed CCC) that outperforms synthesized and commercial PGM catalysts for CO oxidation in simulated exhaust streams while showing no signs of inhibition by propene. Diffuse reflectance IR (DRIFTS) and light-off data both indicate low interaction between propene and the CO oxidation active site on this catalyst, and a separation of adsorption sites is proposed as the cause of this inhibition resistance. This catalyst shows great potential as a low-cost component for low temperature exhaust streams that are expected to be a characteristic of future automotive systems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Biphasic catalysis using amphiphilic polyphenols-chelated noble metals as highly active and selective catalysts

    Science.gov (United States)

    Mao, Hui; Yu, Hong; Chen, Jing; Liao, Xuepin

    2013-07-01

    In the field of catalysis, it is highly desired to develop novel catalysts that combine the advantages of both homogeneous and heterogeneous catalysts. Here we disclose that the use of plant pholyphenol as amphiphilic large molecule ligand/stabilizer allows for the preparation of noble metal complex and noble metal nanoparticle catalysts. These catalysts are found to be highly selective and active in aqueous-organic biphasic catalysis of cinnamaldehyde and quinoline, and can be reused at least 3 times without significant loss of activity. Moreover, the catalytic activity and reusability of the catalysts can be rationally controlled by simply adjusting the content of polyphenols in the catalysts. Our strategy may be extended to design a wide range of aqueous-organic biphasic catalysis system.

  8. Ethylene Oligomerization and Polymerization: Alternative Iron Catalysts beyond 2,6-Bisiminopyridyl Iron Complexes

    Institute of Scientific and Technical Information of China (English)

    Suyun Jie; Shu Zhang; Wenjuan Zhang; Yingxia Song; Junxian Hou; Wen-Hua Sun

    2005-01-01

    @@ 1Introduction Polyolefin industry arrives the option to transfer from multiple-site systems of the classical Ziegler-Natta catalysts to more sophisticated single-site catalysts. The late-transition metal compounds were traditionally assumed with poor polymerization properties due to the highly competitive chain-termination step, and produced the short-chain oligomers up to 40 carbon atoms (SHOP catalysts). Recently the polyolefins employing latetransition metal complexes as catalysts became a hot research subject with the pioneering works by Brookhart and Gibson. It is promising for nickel catalysts to use solely ethylene as monomer for highly branched polyethylenes, and the designed nickel catalysts were not useful in industry. It is critical time to investigate the relationship of coordination modes of nickel complexes and its catalytic activities and the properties of resultant polyethylenes.

  9. Biomimetic catalysts responsive to specific chemical signals

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yan [Iowa State Univ., Ames, IA (United States)

    2015-03-04

    Part 1. Design of Biomimetic Catalysts Based on Amphiphilic Systems The overall objective of our research is to create biomimetic catalysts from amphiphilic molecules. More specifically, we aim to create supramolecular systems that can be used to control the microenvironment around a catalytic center in a biomimetic fashion and apply the learning to construct supramolecular catalysts with novel functions found in enzymatic catalysts. We have prepared synthetic molecules (i.e., foldamers) that could fold into helical structures with nanometer-sized internal hydrophilic cavities. Cavities of this size are typically observed only in the tertiary and quaternary structures of proteins but were formed in our foldamer prepared in just a few steps from the monomer. Similar to many proteins, our foldamers displayed cooperativity in the folding/unfolding equilibrium and followed a two-state conformational transition. In addition, their conformational change could be triggered by solvent polarity, pH, or presence of metal ions and certain organic molecules. We studied their environmentally dependent conformational changes in solutions, surfactant micelles, and lipid bilayer membranes. Unlike conventional rigid supramolecular host, a foldamer undergoes conformational change during guest binding. Our study in the molecular recognition of an oligocholate host yielded some extremely exciting results. Cooperativity between host conformation and host–guest interactions was found to “magnify” weak binding interactions. In other words, since binding affinity is determined by the overall change of free energy during the binding, guest-induced conformational change of the host, whether near or far from the binding site, affects the binding. This study has strong implications in catalysis because enzymes have been hypothesized to harvest similar intramolecular forces to strengthen their binding with the transition state of an enzyme-catalyzed reaction. The supramolecular and

  10. Direct NO decomposition over conventional and mesoporous Cu-ZSM-5 and Cu-ZSM-11 catalysts

    DEFF Research Database (Denmark)

    Kustova, Marina; Rasmussen, Søren Birk; Kustov, Arkadii

    2006-01-01

    Conventional Cu-ZSM-5 has for many years been recognized as a unique catalyst for direct NO decomposition. Zeolite-based catalysts have a crystallographically well-defined microporous structure. In such microporous catalysts, the creation and accessibility of the active sites is often influenced...... by the geometry of the pore system. To improve these catalysts, secondary mesoporous systems can benefitially be introduced into the structure of conventional zeolites. Here, this approach was used with Cu-containing ZSM-5 and ZSM-11 type mesoporous zeolite catalysts, which were used as catalysts for direct...... NO decomposition. It was discovered that introducing mesoporosity into the conventional materials leads to a significant improvement of the catalytic activity. Additionally, mesoporous Cu-ZSM-11 catalyst was found to be about twice as active as mesoporous Cu-ZSM-5. This difference is attributed to the fact...

  11. Deactivation by carbon of iron catalysts for indirect liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, C.H.

    1990-10-29

    This report describes recent progress in a fundamental, three-year investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for synthesis, the objectives of which are: determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation over a range of CO concentrations, CO:H{sub 2} ratios, and temperatures; model the rates of deactivation of the same catalysts in fixed-bed reactors. During the fourteenth quarter design of software for a computer-automated reactor system to be used in the kinetic and deactivation studies was continued. Further progress was made toward the completion of the control language, control routines, and software for operating this system. Progress was also made towards testing of the system hardware and software. 47 refs.

  12. Oscillatory behaviour of isomers of hydroxybenzoic acid with and without catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Masood A.; Rastogi, R.P.; Peerzada, G.M. [University of Kashmir, Srinagar (India). Dept. of Chemistry]. E-mail: nath_masood@yahoo.co.in

    2009-07-01

    The present work establishes and compares the oscillatory behaviour of mono-, di- and trihydroxybenzoic acids as organic substrates in acidic bromate (1.0 mol L{sup -1} H{sub 2}SO{sub 4}) without catalyst and in the presence of Mn{sup 2+} ion as the main catalyst. The oscillations are also affected by other catalyst such as Fe{sup 2+} ion. Further, the oscillations start diminishing in mixed catalyst systems. The experimental parameters were obtained potentiometrically and the results have been interpreted on the basis of FKN mechanism. (author)

  13. Control of branch formation in ethylene polymerization by a [Ni(h3-2-MeC3H4(diimine] PF6 / DEAC catalyst system

    Directory of Open Access Journals (Sweden)

    Escher Fernanda F. N.

    2001-01-01

    Full Text Available The polymerization of ethylene mediated by [Ni(eta³-2-MeC3H4{ArN=C(HC(H=NAr}] PF6, Ar = 2,6-C6H3iPr2 /DEAC catalyst precursor under mild reaction conditions (reaction temperature between -10 ºC and 25 ºC and ethylene pressure between 109 and 1520 kPa yields high molecular weight branched polyethylene. The degree of branching was modulated by a careful choice of reaction conditions. Thus, at 0 ºC and 109 kPa, the branching degree was 17 branches/1000 backbone carbon atoms and at 25 ºC, it went up to 90 branches/1000 backbone carbon atoms. The nature of the observed branches (methyl, ethyl and longer, their quantity and distribution along the polymer backbone chain can be rationalized in terms of a chain walking process and control of the extend of isomerization by the steric hindrance of the growing chain.

  14. Design of a core–shell Pt–SiO2 catalyst in a reverse microemulsion system: Distinctive kinetics on CO oxidation at low temperature

    KAUST Repository

    Al Mana, Noor

    2016-06-28

    The mechanism of formation of Pt@SiO2 as a model of core–shell nanoparticles via water-in-oil reverse microemulsions was studied in detail. By controlling the time of growth of Pt precursors, Pt(OH)x, after hydrolysis in NH3 aq. before adding SiO2 precursor (TEOS), Pt nanoparticles with a narrow size distribution were produced, from ultrafine metal nanoparticles (<1 nm) to 6 nm nanocrystals. Separately, the thickness of SiO2 was controllably synthesized from 1 to 15 nm to yield different Pt@SiO2 materials. The Pt@SiO2 core–shell catalysts exhibited a higher rate of CO oxidation by one order of magnitude with a positive order regarding CO pressure. The SiO2 shell did not perturb the Pt chemical nature, but it provided different coverage of CO in steady-state CO oxidation. © 2016 Elsevier Inc.

  15. Static and dynamic structural characterization of nanomaterial catalysts

    Science.gov (United States)

    Masiel, Daniel Joseph

    Heterogeneous catalysts systems are pervasive in industry, technology and academia. These systems often involve nanostructured transition metal particles that have crucial interfaces with either their supports or solid products. Understanding the nature of these interfaces as well as the structure of the catalysts and support materials themselves is crucial for the advancement of catalysis in general. Recent developments in the field of transmission electron microscopy (TEM) including dynamic transmission electron microscopy (DTEM), electron tomography, and in situ techniques stand poised to provide fresh insight into nanostructured catalyst systems. Several electron microscopy techniques are applied in this study to elucidate the mechanism of silica nanocoil growth and to discern the role of the support material and catalyst size in carbon dioxide and steam reforming of methane. The growth of silica nanocoils by faceted cobalt nanoparticles is a process that was initially believed to take place via a vapor-liquid-solid growth mechanism similar to other nanowire growth techniques. The extensive TEM work described here suggests that the process may instead occur via transport of silicate and silica species over the nanoparticle surface. Electron tomography studies of the interface between the catalyst particles and the wire indicate that they grow from edges between facets. Studies on reduction of the Co 3O4 nanoparticle precursors to the faceted pure cobalt catalysts were carried out using DTEM and in situ heating. Supported catalyst systems for methane reforming were studied using dark field scanning TEM to better understand sintering effects and the increased activity of Ni/Co catalysts supported by carbon nanotubes. Several novel electron microscopy techniques are described including annular dark field DTEM and a metaheuristic algorithm for solving the phase problem of coherent diffractive imaging. By inserting an annular dark field aperture into the back focal

  16. CATALYST ACTIVITY MAINTENANCE FOR THE LIQUID PHASE SYNTHESIS GAS-TO-DIMETHYL ETHER PROCESS PART II: DEVELOPMENT OF ALUMINUM PHOSPHATE AS THE DEHYDRATION CATALYST FOR THE SINGLE-STEP LIQUID PHASE SYNGAS-TO-DME PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Xiang-Dong Peng

    2002-05-01

    At the heart of the single-step liquid phase syngas-to-DME process (LPDME{trademark}) is a catalyst system that can be active as well as stable. In the Alternative Fuels I program, a dual-catalyst system containing a Cu-based commercial methanol synthesis catalyst (BASF S3-86) and a commercial dehydration material ({gamma}-alumina) was demonstrated. It provided the productivity and selectivity expected from the LPDME process. However, the catalyst system deactivated too rapidly to warrant a viable commercial process [1]. The mechanistic investigation in the early part of the DOE's Alternative Fuels II program revealed that the accelerated catalyst deactivation under LPDME conditions is due to detrimental interaction between the methanol synthesis catalyst and methanol dehydration catalyst [2,3]. The interaction was attributed to migration of Cu- and/or Zn-containing species from the synthesis catalyst to the dehydration catalyst. Identification of a dehydration catalyst that did not lead to this detrimental interaction while retaining adequate dehydration activity was elusive. Twenty-nine different dehydration materials were tested, but none showed the desired performance [2]. The search came to a turning point when aluminum phosphate was tested. This amorphous material is prepared by precipitating a solution containing Al(NO{sub 3}){sub 3} and H{sub 3}PO{sub 4} with NH{sub 4}OH, followed by washing, drying and calcination. The aluminum phosphate catalyst has adequate dehydration activity and good stability. It can co-exist with the Cu-based methanol synthesis catalyst without negatively affecting the latter catalyst's stability. This report documents the details of the development of this catalyst. These include initial leads, efforts in improving activity and stability, investigation and development of the best preparation parameters and procedures, mechanistic understanding and resulting preparation guidelines, and the accomplishments of this work.

  17. Studies on PEM Fuel Cell Noble Metal Catalyst Dissolution

    DEFF Research Database (Denmark)

    Ma, Shuang; Skou, Eivind Morten

    . Membrane Electrode Assembly (MEA) is commonly considered as the heart of cell system [2]. Degradation of the noble metal catalysts in MEAs especially Three-Phase-Boundary (TPB) is a key factor directly influencing fuel cell durability. In this work, electrochemical degradation of Pt and Pt/Ru alloy were......Incredibly vast advance has been achieved in fuel cell technology regarding to catalyst efficiency, improvement of electrolyte conductivity and optimization of cell system. With breathtakingly accelerating progress, Proton Exchange Membrane Fuel Cells (PEMFC) is the most promising and most widely...

  18. A pentanuclear iron catalyst designed for water oxidation

    Science.gov (United States)

    Okamura, Masaya; Kondo, Mio; Kuga, Reiko; Kurashige, Yuki; Yanai, Takeshi; Hayami, Shinya; Praneeth, Vijayendran K. K.; Yoshida, Masaki; Yoneda, Ko; Kawata, Satoshi; Masaoka, Shigeyuki

    2016-02-01

    Although the oxidation of water is efficiently catalysed by the oxygen-evolving complex in photosystem II (refs 1 and 2), it remains one of the main bottlenecks when aiming for synthetic chemical fuel production powered by sunlight or electricity. Consequently, the development of active and stable water oxidation catalysts is crucial, with heterogeneous systems considered more suitable for practical use and their homogeneous counterparts more suitable for targeted, molecular-level design guided by mechanistic understanding. Research into the mechanism of water oxidation has resulted in a range of synthetic molecular catalysts, yet there remains much interest in systems that use abundant, inexpensive and environmentally benign metals such as iron (the most abundant transition metal in the Earth’s crust and found in natural and synthetic oxidation catalysts). Water oxidation catalysts based on mononuclear iron complexes have been explored, but they often deactivate rapidly and exhibit relatively low activities. Here we report a pentanuclear iron complex that efficiently and robustly catalyses water oxidation with a turnover frequency of 1,900 per second, which is about three orders of magnitude larger than that of other iron-based catalysts. Electrochemical analysis confirms the redox flexibility of the system, characterized by six different oxidation states between FeII5 and FeIII5; the FeIII5 state is active for oxidizing water. Quantum chemistry calculations indicate that the presence of adjacent active sites facilitates O-O bond formation with a reaction barrier of less than ten kilocalories per mole. Although the need for a high overpotential and the inability to operate in water-rich solutions limit the practicality of the present system, our findings clearly indicate that efficient water oxidation catalysts based on iron complexes can be created by ensuring that the system has redox flexibility and contains adjacent water-activation sites.

  19. Edge termination of MoS2 and CoMoS catalyst particles

    DEFF Research Database (Denmark)

    Byskov, Line Sjolte; Nørskov, Jens Kehlet; Clausen, B. S.;

    2000-01-01

    The edge termination of MoS2 and CoMoS catalyst particles is studied by density functional calculations. We show that for structures without vacancies Mo-terminated edges have the lowest edge energies. Creation of vacancies, which are believed to be active sites in these catalyst systems, leads...

  20. Study of Nanoconfined Phases for the Rational Synthesis of Supported Catalysts

    NARCIS (Netherlands)

    Eggenhuisen, T.M.

    2012-01-01

    Catalysts are indispensable for modern day society since they are used in the production of transportation fuels, chemicals and materials. Understanding the structure-activity relation for a catalytic system allows the formulation of catalyst structure specifications that optimizes activity, selecti

  1. Methods and catalysts for making biodiesel from the transesterification and esterification of unrefined oils

    Science.gov (United States)

    Yan, Shuli [Detroit, MI; Salley, Steven O [Grosse Pointe Park, MI; Ng, K Y. Simon [West Bloomfield, MI

    2012-04-24

    A method of forming a biodiesel product and a heterogeneous catalyst system used to form said product that has a high tolerance for the presence of water and free fatty acids (FFA) in the oil feedstock is disclosed. This catalyst system may simultaneously catalyze both the esterification of FAA and the transesterification of triglycerides present in the oil feedstock. The catalyst system according to one aspect of the present disclosure represents a class of zinc and lanthanum oxide heterogeneous catalysts that include different ratios of zinc oxide to lanthanum oxides (Zn:La ratio) ranging from about 10:0 to 0:10. The Zn:La ratio in the catalyst is believed to have an effect on the number and reactivity of Lewis acid and base sites, as well as the transesterification of glycerides, the esterification of fatty acids, and the hydrolysis of glycerides and biodiesel.

  2. Supramolecular water oxidation with rubda-based catalysts

    KAUST Repository

    Richmond, Craig J.

    2014-11-05

    Extremely slow and extremely fast new water oxidation catalysts based on the Rubda (bda = 2,2′-bipyri-dine-6,6′-dicarboxylate) systems are reported with turnover frequencies in the range of 1 and 900 cycless"1, respectively. Detailed analyses of the main factors involved in the water oxidation reaction have been carried out and are based on a combination of reactivity tests, electrochemical experiments, and DFT calculations. These analyses give a convergent interpretation that generates a solid understanding of the main factors involved in the water oxidation reaction, which in turn allows the design of catalysts with very low energy barriers in all the steps involved in the water oxidation catalytic cycle. We show that for this type of system p-stacking interactions are the key factors that influence reactivity and by adequately controlling them we can generate exceptionally fast water oxidation catalysts.

  3. Au-Based Catalysts: Electrochemical Characterization for Structural Insights

    Directory of Open Access Journals (Sweden)

    Valentina Pifferi

    2016-02-01

    Full Text Available Au-based catalysts are widely used in important processes because of their peculiar characteristics. The catalyst performance depends strongly on the nature and structure of the metal nanoparticles, especially in the case of bimetallic catalysts where synergistic effects between the two metals can be occasionally seen. In this paper, it is shown that electrochemical characterisation (cyclovoltammetry CV and electrochemical impedance spectroscopy EIS of AuPd systems can be used to determine the presence of an electronic interaction between the two metals, thus providing a strong support in the determination of the nature of the synergy between Au and Pd in the liquid phase oxidation of alcohols. However, it seems likely that the strong difference in the catalytic behavior between the single metals and the bimetallic system is connected not only to the redox behaviour, but also to the energetic balance between the different elementary steps of the reaction.

  4. Regeneration of Hydrotreating and FCC Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    CM Wai; JG Frye; JL Fulton; LE Bowman; LJ Silva; MA Gerber

    1999-09-30

    Hydrotreating, hydrocracking, and fluid catalytic cracking (FCC) catalysts are important components of petroleum refining processes. Hydrotreating and hydrocracking catalysts are used to improve the yield of high-quality light oil fractions from heavier crude oil and petroleum feedstocks containing high levels of impurities. FCC catalysts improve the yield of higher octane gasoline from crude oil. Residuum hydrotreating and cracking catalysts are susceptible to irreversible deactivation caused by adsorption of sulfur and by metals impurities, such as vanadium and nickel. The gradual buildup of these impurities in a hydrotreating catalyst eventually plugs the pores and deactivates it. Nickel and vanadium adversely affect the behavior of cracking catalysts, reducing product yield and quality. Replacing deactivated catalysts represents a significant cost in petroleum refining. Equally important are the costs and potential liabilities associated with treating and disposing spent catalysts. For example, recent US Environmental Protection Agency rulings have listed spent hydrotreating and hydrorefining catalysts as hazardous wastes. FCC catalysts, though more easily disposed of as road-base or as filler in asphalt and cement, are still an economic concern mainly because of the large volumes of spent catalysts generated. New processes are being considered to increase the useful life of catalysts or for meeting more stringent disposal requirements for spent catalysts containing metals. This report discusses a collaborative effort between Pacific Northwest National Laboratory (PNNL) and Phillips Petroleum, Inc., to identify promising chemical processes for removing metals adhered to spent hydrodesulfurization (HDS, a type of hydrotreating catalyst) and FCC catalysts. This study, conducted by PNNL, was funded by the US Department of Energy's Bartlesville Project Office. Fresh and spent catalysts were provided by Phillips Petroleum. The FCC catalyst was a rare

  5. Methyltrioxorhenium as catalyst for olefin metathesis

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, W.A. (Technische Univ. Muenchen, Garching (Germany). Anorganisch-Chemisches Inst.); Wagner, W. (Consortium fuer Elektrochemische Industrie GmbH, Muenchen (Germany)); Flessner, U.N.; Volkhardt, U.; Komber, H. (Institut fuer Technologie der Polymere, Dresden (Germany))

    1991-12-01

    No cocatalysts are needed as additives when methyltrioxorhenium (MTO) supported on acidic carriers is employed to catalyze the metathesis of functionalized olefins. A typical system is MTO/Al{sub 2}O{sub 3}-SiO{sub 2}, which is active, for instance, in the metathesis of allyl halides, allylsilanes, unsaturated carboxylates, and nitriles. MTO in combination with R{sub n}AlCl{sub 3-n} is a homogeneous catalyst in ring-opening polymerizations (R = CH{sub 3}, C{sub 2}H{sub 5}; n = 1,2). (orig.).

  6. Catalyst containing oxygen transport membrane

    Science.gov (United States)

    Christie, Gervase Maxwell; Wilson, Jamie Robyn; van Hassel, Bart Antonie

    2012-12-04

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  7. Catalyst containing oxygen transport membrane

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Jonathan A.; Wilson, Jamie R.; Christie, Gervase Maxwell; Petigny, Nathalie; Sarantopoulos, Christos

    2017-02-07

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a microstructure exhibiting substantially uniform pore size distribution as a result of using PMMA pore forming materials or a bi-modal particle size distribution of the porous support layer materials. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  8. Templating Routes to Supported Oxide Catalysts by Design

    Energy Technology Data Exchange (ETDEWEB)

    Notestein, Justin M. [Northwestern Univ., Evanston, IL (United States)

    2016-09-08

    The rational design and understanding of supported oxide catalysts requires at least three advancements, in order of increasing complexity: the ability to quantify the number and nature of active sites in a catalytic material, the ability to place external controls on the number and structure of these active sites, and the ability to assemble these active sites so as to carry out more complex functions in tandem. As part of an individual investigator research program that is integrated with the Northwestern University Institute for Catalysis in Energy Processes (ICEP) as of 2015, significant advances were achieved in these three areas. First, phosphonic acids were utilized in the quantitative assessment of the number of active and geometrically-available sites in MOx-SiO2 catalysts, including nanocrystalline composites, co-condensed materials, and grafted structures, for M=Ti, Zr, Hf, Nb, and Ta. That work built off progress in understanding supported Fe, Cu, and Co oxide catalysts from chelating and/or multinuclear precursors to maximize surface reactivity. Secondly, significant progress was made in the new area of using thin oxide overcoats containing ‘nanocavities’ from organic templates as a method to control the dispersion and thermal stability of subsequently deposited metal nanoparticles or other catalytic domains. Similar methods were used to control surface reactivity in SiO2-Al2O3 acid catalysts and to control reactant selectivity in Al2O3-TiO2 photocatalysts. Finally, knowledge gained from the first two areas has been combined to synthesize a tandem catalyst for hydrotreating reactions and an orthogonal tandem catalyst system where two subsequent reactions in a reaction network are independently controlled by light and heat. Overall, work carried out under this project significantly advanced the knowledge of synthesis-structure-function relationships in supported

  9. Catalyst and electrolyte synergy in Li-O2 batteries.

    Science.gov (United States)

    Gittleson, Forrest S; Sekol, Ryan C; Doubek, Gustavo; Linardi, Marcelo; Taylor, André D

    2014-02-21

    Understanding the interactions between catalyst and electrolyte in Li-O2 systems is crucial to improving capacities, efficiencies, and cycle life. In this study, supported noble metal catalysts Pt/C, Pd/C, and Au/C were paired with popular Li-O2 electrolyte solvents dimethoxyethane (DME), tetraglyme (TEGDME), and dimethyl sulfoxide (DMSO). The effects of these combinations on stability, kinetics, and activity were assessed. We show evidence of a synergistic effect between Pt and Pd catalysts and a DMSO-based electrolyte which enhances the kinetics of oxygen reduction and evolution reactions. DME and TEGDME are more prone to decomposition and less kinetically favorable for oxygen reduction and evolution than DMSO. While the order of oxygen reduction onset potentials with each catalyst was found to be consistent across electrolyte (Pd > Pt > Au), larger overpotentials with DME and TEGDME, and negative shifts in onset after only five cycles favor the stability of a DMSO electrolyte. Full cell cycling experiments confirm that catalyst-DMSO combinations produce up to 9 times higher discharge capacities than the same with TEGDME after 20 cycles (∼707.4 vs. 78.8 mA h g(-1) with Pd/C). Ex situ EDS and in situ EIS analyses of resistive species in the cathode suggest that improvements in capacity with DMSO are due to a combination of greater electrolyte conductivity and catalyst synergies. Our findings demonstrate that co-selection of catalyst and electrolyte is necessary to exploit chemical synergies and improve the performance of Li-O2 cells.

  10. Novel reaction engineering concepts for catalyst immobilisation in hydroformylation

    Energy Technology Data Exchange (ETDEWEB)

    Cole-Hamilton, D.J.; Desset, S.L.; Muldoon, M.J. [St. Andrews Univ. (United Kingdom). EaStChem, School of Chemistry; Hintermair, U. [St. Andrews Univ. (United Kingdom). EaStChem, School of Chemistry]|[CNRS, Lyon (France). Laboratoire de Chimie Organometallique de Surface; Santini, C.C. [CNRS, Lyon (France). Laboratoire de Chimie Organometallique de Surface

    2006-07-01

    Various methods for the separation of the aldehyde products from the catalyst and any solvent during or after hydroformylation reactions of long chain alkenes are reviewed. The catalyst can be immobilized on a soluble or insoluble support or in a phase that does not mix with the product phase under the separation conditions. Aqueous, fluorous, and ionic liquid biphasic systems as well as systems involving scCO{sub 2} sometimes in conjunction with one or other of the types of solvents listed above. Hybrid systems in which a liquid phase containing the catalyst is supported on a microporous solid support are also discussed. The advantages and disadvantages of the various systems are considered and new results concerning the addition of [1-octyl-3-methylimidazolium]Br to aqueous biphasic systems and the use of supercritical fluids to transport substrates over supported ionic liquid phases are presented. Both of these new approaches give high reaction rates, which for the supported ionic liquid phase catalysts can be maintained for at least 40 h of continuous flow operation. For the aqueous biphasic systems, leaching is low and phase separation is fast. (orig.)

  11. Productions of sunflower oil biodiesel and used cooking oil through heterogeneous catalysts compared to conventional homogeneous catalysts

    Science.gov (United States)

    Gutiérrez-Zapata, C. A.; Blanco Martínez, D.; Collazos, C. A.; Castellanos Acuña, H. E.; Cuervo, J. A.; Fernandez, C. P.

    2017-01-01

    This document compares homogeneous and heterogeneous catalysts used by production of biodiesel of sunflower oil and cooking oil used in frying. For this, NaOH was used as a catalyst homogeneous, and K2CO3 and Na2CO3 supported in gamma-alumina (K2CO3/γ Al2O3 y Na2CO3 /γ-Al2O3) were synthesized as heterogeneous catalysts, which were characterized by X-ray diffraction. The transesterification tests were carried out for the sunflower oil and used cooking oil, in a reflux system, to different molar relations methanol/oil, depending on the type of oil and characterization of the same. The reflux system is performed at a temperature of 55-60°C for one hour. Finally, biofuel was characterized and the yield of the reaction was calculated.

  12. Monitoring catalysts at work in their final form: spectroscopic investigations on a monolithic catalyst

    DEFF Research Database (Denmark)

    Rasmussen, Søren B.; Bañares, Miguel A.; Bazin, Philippe;

    2012-01-01

    A monolithic vanadia–titania based catalyst has been subjected to studies with in situ FTIR spectroscopy coupled with mass spectrometry, during the SCR (Selective Catalytic Reduction) reaction. A device based on a transmission reactor cell for monolithic samples was constructed, dedicated to the ...... with other surface or bulk sensitive techniques, e.g. Raman and UV-vis spectroscopy.......A monolithic vanadia–titania based catalyst has been subjected to studies with in situ FTIR spectroscopy coupled with mass spectrometry, during the SCR (Selective Catalytic Reduction) reaction. A device based on a transmission reactor cell for monolithic samples was constructed, dedicated....... The observations reported here serve as a demonstration of the great potential for the application of operando spectroscopy on monolithic systems. This cross disciplinary approach aims to identify reaction pathways, active sites, intermediate- and spectator-species for catalytic reactions under truly industrial...

  13. Novel Fischer-Tropsch catalysts. [DOE patent

    Science.gov (United States)

    Vollhardt, K.P.C.; Perkins, P.

    Novel compounds are described which are used as improved Fischer-Tropsch catalysts particularly for the conversion of CO + H/sub 2/ to gaseous and liquid hydrocarbons at milder conditions than with prior catalysts.

  14. Rhenium Nanochemistry for Catalyst Preparation

    Directory of Open Access Journals (Sweden)

    Vadim G. Kessler

    2012-08-01

    Full Text Available The review presents synthetic approaches to modern rhenium-based catalysts. Creation of an active center is considered as a process of obtaining a nanoparticle or a molecule, immobilized within a matrix of the substrate. Selective chemical routes to preparation of particles of rhenium alloys, rhenium oxides and the molecules of alkyltrioxorhenium, and their insertion into porous structure of zeolites, ordered mesoporous MCM matrices, anodic mesoporous alumina, and porous transition metal oxides are considered. Structure-property relationships are traced for these catalysts in relation to such processes as alkylation and isomerization, olefin metathesis, selective oxidation of olefins, methanol to formaldehyde conversion, etc.

  15. Quick Guide to Flash Catalyst

    CERN Document Server

    Elmansy, Rafiq

    2011-01-01

    How do you transform user interface designs created in Photoshop or Illustrator into interactive web pages? It's easier than you think. This guide shows you how to use Adobe Flash Catalyst to create interactive UIs and website wireframes for Rich Internet Applications-without writing a single line of code. Ideal for web designers, this book introduces Flash Catalyst basics with detailed step-by-step instructions and screenshots that illustrate every part of the process. You'll learn hands-on how to turn your static design or artwork into working user interfaces that can be implemented in Fla

  16. Paraffin Alkylation Using Zeolite Catalysts in a slurry reactor: Chemical Engineering Principles to Extend Catalyst Lifetime

    NARCIS (Netherlands)

    Jong, K.P. de; Mesters, C.M.A.M.; Peferoen, D.G.R.; Brugge, P.T.M. van; Groot, C. de

    1996-01-01

    The alkylation of isobutane with 2-butene is carried out using a zeolitic catalyst in a well stirred slurry reactor. Whereas application of fixed bed technology using a solid acid alkylation catalyst has in the led to catalysts lifetimes in the range of minutes, in this work we report catalyst

  17. Water/Oil Biphasic Hydroformylation of Higher Olefins over a TPPTS-Rh/SiO2 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Hejun Zhu; Yunjie Ding; Fu Yang; Li Yan; Jianmin Xiong; Hongmei Yin; Liwu Lin

    2004-01-01

    A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous highsurface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of mass transfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performance for hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of the traditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersed Rh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation of higher olefins such as 1-dodecene.

  18. Long-Term Testing of Rhodium-Based Catalysts for Mixed Alcohol Synthesis – 2013 Progress Report

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-23

    The U.S. Department of Energy’s Pacific Northwest National Laboratory has been conducting research since 2005 to develop a catalyst for the conversion of synthesis gas (carbon monoxide and hydrogen) into mixed alcohols for use in liquid transportation fuels. Initially, research involved screening possible catalysts based on a review of the literature, because at that time, there were no commercial catalysts available. The screening effort resulted in a decision to focus on catalysts containing rhodium and manganese. Subsequent research identified iridium as a key promoter for this catalyst system. Since then, research has continued to improve rhodium/manganese/iridium-based catalysts, optimizing the relative and total concentrations of the three metals, examining baseline catalysts on alternative supports, and examining effects of additional promoters. Testing was continued in FY 2013 to evaluate the performance and long-term stability of the best catalysts tested to date. Three tests were conducted. A long-term test of over 2300 hr duration at a single set of operating conditions was conducted with the best carbon-supported catalyst. A second test of about 650 hr duration at a single set of operating conditions was performed for comparison using the same catalyst formulation on an alternative carbon support. A third test of about 680 hr duration at a single set of operating conditions was performed using the best silica-supported catalyst tested to date.

  19. Pentafluorophenylammonium triflate-CuCl2: A mild, efficient and reusable heterogeneous catalyst system for facile synthesis of 4(3H)-quinazolinones under solvent-free conditions

    Indian Academy of Sciences (India)

    Naser Montazeri; Khalil Pourshamsian; Soghra Yosefiyan; Seydeh Samaneh Momeni

    2012-07-01

    Pentafluorophenylammonium triflate (PFPAT) was found to be highly efficient, and recyclable heterogeneous catalyst for the synthesis of 4(3H)-quinazolinones by cyclocondensation reaction of 2-aminobenzamide with aryl aldehydes in the presence of CuCl2 as co-catalyst in good to excellent yields under solvent-free conditions. The present methodology offers several advantages, such as simple procedure with an easy work-up, high yields, short reaction times, and the absence of any volatile or hazardous organic solvents. Moreover, the catalyst can be easily recovered and reused at least three times with only slight reduction in its catalytic activity.

  20. On-line regeneration of hydrodesulfurization catalyst

    Science.gov (United States)

    Preston, Jr., John L.

    1980-01-01

    A hydrotreating catalyst is regenerated as it concurrently hydrotreats a hydrocarbon fuel by introducing a low concentration of oxygen into the catalyst bed either continuously or periodically. At low oxygen concentrations the carbon deposits on the catalyst are burned off without harming the catalyst and without significantly affecting the hydrotreating process. In a preferred embodiment the hydrotreating process is hydrodesulfurization, and regenerating is done periodically with oxygen concentrations between 0.1 and 0.5 volume percent.

  1. Determination of the dominant catalyst derived from the classic [RhCp*Cl₂]₂ precatalyst system: Is it single-metal Rh₁Cp*-based, subnanometer Rh₄ cluster-based, or Rh(0)n nanoparticle-based cyclohexene hydrogenation catalysis at room temperature and mild pressures?

    Energy Technology Data Exchange (ETDEWEB)

    Bayram, Ercan [Colorado State Univ., Fort Collins, CO (United States); Linehan, John C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fulton, John L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Szymczak, Nathaniel K. [Univ. of Michigan, Ann Arbor, MI (United States); Finke, Richard G. [Colorado State Univ., Fort Collins, CO (United States)

    2015-05-27

    Determining the kinetically dominant catalyst in a given catalytic system is a forefront topic in catalysis. The [RhCp*Cl₂]₂ (Cp* =[η⁵-C₅(CH₃)₅]) system pioneered by Maitlis and co-workers is a classic precatalyst system from which homogeneous mononuclear Rh₁, subnanometer Rh₄ cluster, and heterogeneous polymetallic Rh(0)n nanoparticle have all arisen as viable candidates for the true hydrogenation catalyst, depending on the precise substrate, H₂ pressure, temperature, and catalyst concentration conditions. Addressed herein is the question of whether the prior assignment of homogeneous, mononuclear Rh₁Cp*-based catalysis is correct, or are trace Rh₄ subnanometer clusters or possibly Rh(0)n nanoparticles the dominant, actual cyclohexene hydrogenation catalyst at 22 °C and 2.7 atm initial H₂ pressure? The observation herein of Rh₄ species by in operando-X-ray absorption fine structure (XAFS) spectroscopy, at the only slightly more vigorous conditions of 26 °C and 8.3 atm H₂ pressure, and the confirmation of Rh₄ clusters by ex situ mass spectroscopy raises the question of the dominant, room temperature, and mild pressure cyclohexene hydrogenation catalyst derived from the classic [RhCp*Cl₂]₂ precatalyst pioneered by Maitlis and co-workers. Ten lines of evidence are provided herein to address the nature of the true room temperature and mild pressure cyclohexene hydrogenation catalyst derived from [RhCp*Cl₂]₂. Especially significant among those experiments are quantitative catalyst poisoning experiments, in the present case using 1,10-phenanthroline. Those poisoning studies allow one to distinguish mononuclear Rh₁, subnanometer Rh₄ cluster, and Rh(0)n nanoparticle catalysis hypotheses. The evidence obtained provides a compelling case for a mononuclear, Rh₁Cp*-based cyclohexene hydrogenation catalyst at 22 °C and 2.7 atm H₂ pressure. The resultant methodology, especially the quantitative

  2. Development of Non-Noble Metal Ni-Based Catalysts for Dehydrogenation of Methylcyclohexane

    KAUST Repository

    Al-ShaikhAli, Anaam H.

    2016-11-30

    Liquid organic chemical hydride is a promising candidate for hydrogen storage and transport. Methylcyclohexane (MCH) to toluene (TOL) cycle has been considered as one of the feasible hydrogen carrier systems, but selective dehydrogenation of MCH to TOL has only been achieved using the noble Pt-based catalysts. The aim of this study is to develop non-noble, cost-effective metal catalysts that can show excellent catalytic performance, mainly maintaining high TOL selectivity achievable by Pt based catalysts. Mono-metallic Ni based catalyst is a well-known dehydrogenation catalyst, but the major drawback with Ni is its hydrogenolysis activity to cleave C-C bonds, which leads to inferior selectivity towards dehydrogenation of MCH to TOL. This study elucidate addition of the second metal to Ni based catalyst to improve the TOL selectivity. Herein, ubiquitous bi-metallic nanoparticles catalysts were investigated including (Ni–M, M: Ag, Zn, Sn or In) based catalysts. Among the catalysts investigated, the high TOL selectivity (> 99%) at low conversions was achieved effectively using the supported NiZn catalyst under flow of excess H2. In this work, a combined study of experimental and computational approaches was conducted to determine the main role of Zn over Ni based catalyst in promoting the TOL selectivity. A kinetic study using mono- and bimetallic Ni based catalysts was conducted to elucidate reaction mechanism and site requirement for MCH dehydrogenation reaction. The impact of different reaction conditions (feed compositions, temperature, space velocity and stability) and catalyst properties were evaluated. This study elucidates a distinctive mechanism of MCH dehydrogenation to TOL reaction over the Ni-based catalysts. Distinctive from Pt catalyst, a nearly positive half order with respect to H2 pressure was obtained for mono- and bi-metallic Ni based catalysts. This kinetic data was consistent with rate determining step as (somewhat paradoxically) hydrogenation

  3. TEST REPORT OF MOBILE SOURCE EMISSIONS CONTROL DEVICES DONALDSON COMPANY INC.SERIES 6000 DISEL OXIDATION CATALYST MUFFLER AND SPIRACLE CLOSED CRANKCASE FILTRATION SYSTEM

    Science.gov (United States)

    This report is on testing of a Donaldson Corp. catalytic muffler and closed crankcase filtration system for diesel trucks. It verified the emissions for these systems using low sufur and ultra low sulfur fuel.

  4. 板式催化剂生产线原料加料系统设计与改进%Design and Improvement for Raw material Feeding System of Plate Catalyst Production Line

    Institute of Scientific and Technical Information of China (English)

    郑承霞; 杨光; 梅辉

    2015-01-01

    A SCR catalyst production line is introduce by a steel mill,artificial form of raw materials is used in mixing ma-chine.The efficiency is low and worker's labor load is heavy.In order to improve the efficiency and lighten the labor load,The au-thor designs a raw material feeding system which exposes some problems in practical application.Improvement should be made to perfect the system.%某钢厂引进SCR脱硝板式催化剂生产线,原料市场采购,原料加入混料机采用人工形式,加料效率低,劳动负荷大,为了提高生产效率,降低工人劳动负荷,作者设计了一套原料加料系统,但实际使用中,出现了一些问题,需要改进。

  5. Comparing kinetic profiles between bifunctional and binary type of Zn(salen-based catalysts for organic carbonate formation

    Directory of Open Access Journals (Sweden)

    Carmen Martín

    2014-08-01

    Full Text Available Zn(salen complexes have been employed as active catalysts for the formation of cyclic carbonates from epoxides and CO2. A series of kinetic experiments was carried out to obtain information about the mechanism for this process catalyzed by these complexes and in particular about the order-dependence in catalyst. A comparative analysis was done between the binary catalyst system Zn(salphen/NBu4I and a bifunctional system Zn(salpyr·MeI with a built-in nucleophile. The latter system demonstrates an apparent second-order dependence on the bifunctional catalyst concentration and thus follows a different, bimetallic mechanism as opposed to the binary catalyst that is connected with a first-order dependence on the catalyst concentration and a monometallic mechanism.

  6. Efficient epoxidation of propene using molecular catalysts

    DEFF Research Database (Denmark)

    Markovits, Iulius I. E.; Anthofer, Michael H.; Kolding, Helene

    2014-01-01

    The epoxidation of propene is performed in homogeneous phase using various molecular catalysts and H2O2 or tert-butyl hydroperoxide as oxidants. A comparison between some molybdenum catalysts and methyltrioxorhenium (MTO) shows that the well known Re catalyst is the best among the examined...

  7. Catalysts and methods of using the same

    Energy Technology Data Exchange (ETDEWEB)

    Slowing, Igor Ivan; Kandel, Kapil

    2017-02-14

    The present invention provides a catalyst including a mesoporous silica nanoparticle and a catalytic material comprising iron. In various embodiments, the present invention provides methods of using and making the catalyst. In some examples, the catalyst can be used to hydrotreat fatty acids or to selectively remove fatty acids from feedstocks.

  8. Novel non-platinum metal catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

  9. Supported Catalysts for CO2 Methanation: A Review

    Directory of Open Access Journals (Sweden)

    Patrizia Frontera

    2017-02-01

    Full Text Available CO2 methanation is a well-known reaction that is of interest as a capture and storage (CCS process and as a renewable energy storage system based on a power-to-gas conversion process by substitute or synthetic natural gas (SNG production. Integrating water electrolysis and CO2 methanation is a highly effective way to store energy produced by renewables sources. The conversion of electricity into methane takes place via two steps: hydrogen is produced by electrolysis and converted to methane by CO2 methanation. The effectiveness and efficiency of power-to-gas plants strongly depend on the CO2 methanation process. For this reason, research on CO2 methanation has intensified over the last 10 years. The rise of active, selective, and stable catalysts is the core of the CO2 methanation process. Novel, heterogeneous catalysts have been tested and tuned such that the CO2 methanation process increases their productivity. The present work aims to give a critical overview of CO2 methanation catalyst production and research carried out in the last 50 years. The fundamentals of reaction mechanism, catalyst deactivation, and catalyst promoters, as well as a discussion of current and future developments in CO2 methanation, are also included.

  10. Iron Contamination Mechanism and Reaction Performance Research on FCC Catalyst

    Directory of Open Access Journals (Sweden)

    Zhaoyong Liu

    2015-01-01

    Full Text Available FCC (Fluid Catalytic Cracking catalyst iron poisoning would not only influence units’ product slate; when the poisoning is serious, it could also jeopardize FCC catalysts’ fluidization in reaction-regeneration system and further cause bad influences on units’ stable operation. Under catalytic cracking reaction conditions, large amount of iron nanonodules is formed on the seriously iron contaminated catalyst due to exothermic reaction. These nodules intensify the attrition between catalyst particles and generate plenty of fines which severely influence units’ smooth running. A dense layer could be formed on the catalysts’ surface after iron contamination and the dense layer stops reactants to diffuse to inner structures of catalyst. This causes extremely negative effects on catalyst’s heavy oil conversion ability and could greatly cut down gasoline yield while increasing yields of dry gas, coke, and slurry largely. Research shows that catalyst’s reaction performance would be severely deteriorated when iron content in E-cat (equilibrium catalyst exceeds 8000 μg/g.

  11. Deactivation by carbon of iron catalysts for indirect liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, C H

    1991-02-14

    Progress is reported for a four-year fundamental investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for FT synthesis, the objectives of which were to (1) determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation and (2) model the global rates of deactivation at the surface of the catalyst for the same catalysts. A computer-automated reactor system to be used in the kinetic and deactivation studies was designed, constructed and tested. Kinetic data for CO hydrogenation on unsupported, unpromoted iron, 99% Fe/1% Al{sub 2}O{sub 3}, and K-promoted 99% Fe/1% Al{sub 2}O{sub 3} catalysts were obtained as functions of temperature, reactant particle pressures and time. The activity/selectivity and kinetic data are consistent with those previously reported for supported, unpromoted and promoted iron. Two kinds of deactivation were observed during FT synthesis on these samples: (1) loss of surface area after reduction of unsupported, unpromoted iron at 400{degree}C and (2) loss of activity with time due to carbon deposition, especially in the case of K-promoted 99% Fe/1% A1{sub 2}O{sub 3}. Deactivation rate data were obtained for CO hydrogenation on promoted Fe as a function of time, temperature, and H{sub 2}/CO ratio. 50 refs., 24 figs., 5 tabs.

  12. STUDY OF SOLVENT AND CATALYST INTERACTIONS IN DIRECT COAL LIQUEFACTION

    Energy Technology Data Exchange (ETDEWEB)

    Michael T. Klein

    2000-01-01

    There are several aspects of the Direct Coal Liquefaction process which are not fully understood and which if better understood might lead to improved yields and conversions. Among these questions are the roles of the catalyst and the solvent. While the solvent is known to act by transfer of hydrogen atoms to the free radicals formed by thermal breakdown of the coal in an uncatalyzed system, in the presence of a solid catalyst as is now currently practiced, the yields and conversions are higher than in an uncatalyzed system. The role of the catalyst in this case is not completely understood. DOE has funded many projects to produce ultrafine and more active catalysts in the expectation that better contact between catalyst and coal might result. This approach has met with limited success probably because mass transfer between two solids in a fluid medium i.e. the catalyst and the coal, is very poor. It is to develop an understanding of the role of the catalyst and solvent in Direct Liquefaction that this project was initiated. Specifically it was of interest to know whether direct contact between the coal and the catalyst was important. By separating the solid catalyst in a stainless steel basket permeable to the solvent but not the coal in the liquefaction reactor, it was shown that the catalyst still maintains a catalytic effect on the liquefaction process. There is apparently transfer of hydrogen atoms from the catalyst through the basket wall to the coal via the solvent. Strong hydrogen donor solvents appear to be more effective in this respect than weak hydrogen donors. It therefore appears that intimate contact between catalyst and coal is not a requirement, and that the role of the catalyst may be to restore the hydrogen donor strength to the solvent as the reaction proceeds. A range of solvents of varying hydrogen donor strength was investigated. Because of the extensive use of thermogravimetric analysis in this laboratory in was noted that the peak

  13. Effect of Amine Catalyst Work on Epoxy / Anhydride Curing System%胺类促进剂对环氧树脂/酸酐固化体系的影响

    Institute of Scientific and Technical Information of China (English)

    刘琳; 张晓逆

    2012-01-01

    Adopting liquid methyltetrahydro phthalic anhydride as curing agent, multiplicate amine catalyst (including aliphatic ethanol amine, cycloaliphatic amine, aliphatic amine, quaternary ammonium salt, urea) were used to study diglycidyl ether bisphnol-A epoxy resin system. The best formula was confirmed from the aspects of amine catalyst compatibility, gel time, Tg, pot life etc. The results showed that cycloaliphatic amine (N,N-dimethylcyclohexylamine), aliphatic amine (N-dimethylpropane-l, 3-diamine), quaternary ammonium salt ( 2,2-dimethyl-Propanoic acid ammonium salt) could accelerate the curing system by decreasing the curing temperature from 160? to 100-120? and satisfied the mechanical properties request of FRP wind and casting / encapsulation.%以液体四氢甲基苯酐为固化剂,选用了多种胺类促进剂(包括脂肪类乙醇胺、脂环胺、脂肪胺、季胺盐、脲类)对双酚A缩水甘油醚类环氧树脂固化体系进行研究.从固化促进剂的相容性、凝胶时间、玻璃化转化温度、可使用时间等方面确定最佳配方.研究表明,脂环胺(N,N-二甲环己胺)、脂肪胺[三(二甲胺基丙基)胺]、季胺盐(2,2-二甲基丙酸季胺盐)可以促进双酚A缩水甘油醚类环氧树脂/液体四氢甲基苯酐固化体系的固化,并能使该体系的固化温度从160℃降低到100~120℃,力学性能达到玻璃钢缠绕和灌封浇注料的要求.

  14. Search for new catalysts from a fundamental basis

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, M.; Lytken, O.; Engbaek, J.; Nielsen, G.; Schumacher, N.; Johansson, M.; Chorkendorff, I. [Interdisciplinary Research Center for Catalysis (ICAT), Department of Physics and Department of Chemical Engineering, Building 312, Technical University of Denmark (DTU), DK-2800 Kongens Lyngby (Denmark)

    2005-02-15

    In this overview, we present some of our more fundamental approaches for making new and/or improved catalysts. First, the effect of mono atomic steps is discussed both in relation to the mechanism of the ammonia synthesis, and in terms of relevance for other reactions, such as the steam reforming and methanization processes. The possibility for utilizing steps to improve selectivity is also discussed. It is shown how micro kinetic modelling can be used to predict how the catalyst for the WGS reaction could be improved. Furthermore, an experimental technique is demonstrated, where alloys consisting of up to four metals can be tested under realistic conditions without loosing the ability to study the catalysts with surface science techniques both prior to and after they have been subjected to reaction conditions. Finally, the importance of in situ measurements will be demonstrated for some preliminary investigations of systems of relevance to fuel cell technology.

  15. Focussing the view on Nature's water-splitting catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Messinger, Johannes; Yano, Junko

    2008-01-01

    About 3 billion years ago Nature invented a catalyst that splits water with highefficiency into molecular oxygen and hydrogen equivalents (protons and electrons). This reaction is energetically driven by sun light and the active centre contains relatively cheap and abundant metals: manganese and calcium. This biological system therefore forms the paradigm for all man made attempts for direct solar fuel production and several studies are underway to determine the electronic and geometric structures of this catalyst. In this report we briefly summarize the problems and the current status of these efforts, and propose a DFT-based strategy for obtaining a reliable high resolution structure of this unique catalyst that includes both the inorganic core and the first ligand sphere.

  16. Steam Reforming of Acetic Acid over Co-supported Catalysts: Coupling Ketonization for Greater Stability

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, Stephen D.; Spies, Kurt A.; Mei, Donghai; Kovarik, Libor; Kutnyakov, Igor V.; Li, Xiaohong S.; Dagle, Vanessa; Albrecht, Karl O.; Dagle, Robert A.

    2017-09-11

    We report on the markedly improved stability of a novel 2-bed catalytic system, as compared to a conventional 1-bed steam reforming catalyst, for the production of H2 from acetic acid. The 2-bed catalytic system comprises of i) a basic oxide ketonization catalyst for the conversion of acetic acid to acetone, and a ii) Co-based steam reforming catalyst, both catalytic beds placed in sequence within the same unit operation. Steam reforming catalysts are particularly prone to catalytic deactivation when steam reforming acetic acid, used here as a model compound for the aqueous fraction of bio-oil. Catalysts comprising MgAl2O4, ZnO, CeO2, and activated carbon (AC) both with and without Co-addition were evaluated for conversion of acetic acid and acetone, its ketonization product, in the presence of steam. It was found that over the bare oxide support only ketonization activity was observed and coke deposition was minimal. With addition of Co to the oxide support steam reforming activity was facilitated and coke deposition was significantly increased. Acetone steam reforming over the same Co-supported catalysts demonstrated more stable performance and with less coke deposition than with acetic acid feedstock. DFT analysis suggests that over Co surface CHxCOO species are more favorably formed from acetic acid versus acetone. These CHxCOO species are strongly bound to the Co catalyst surface and could explain the higher propensity for coke formation from acetic acid. Based on these findings, in order to enhance stability of the steam reforming catalyst a dual-bed (2-bed) catalyst system was implemented. Comparing the 2-bed and 1-bed (Co-supported catalyst only) systems under otherwise identical reaction conditions the 2-bed demonstrated significantly improved stability and coke deposition was decreased by a factor of 4.

  17. Perovskite catalysts for oxidative coupling

    Science.gov (United States)

    Campbell, Kenneth D.

    1991-01-01

    Perovskites of the structure A.sub.2 B.sub.2 C.sub.3 O.sub.10 are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  18. Biodiesel production using heterogenous catalyst

    Science.gov (United States)

    The current transesterification of triacylglycerides (TAG) to produce biodiesel is based on the homogenous catalyst method using strong base such as hydroxides or methoxides. However, this method results in a number of problems: (1) acid pre-treatment is required of feedstocks high in free fatty ac...

  19. Polymerization of 4—Vinylpyridine by Lanthanide Coordination Catalyst

    Institute of Scientific and Technical Information of China (English)

    GuoHuaTAN; YiFengZHANG; 等

    2002-01-01

    Polymerization of 4-vinylpyridine was carried out with the lanthanide coordination catalyst. The influence of the component in catalytic system and solvents had been examined. The molecular weight of poly(4-viylpyridine) obtained in CH2Cl2 with Ln(P204)3/Al(i-Bu)3 is more than 20×104.

  20. Polymerization of 4-Vinylpyridine by Lanthanide Coordination Catalyst

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Polymerization of 4-vinylpyridine was carried out with the lanthanide coordination catalyst. The influence of the component in catalytic system and solvents had been examined.The molecular weight of poly(4-vinylpyridinc) obtained in CH2Cl2 with Ln(P204)3/Al(i-Bu)3 is more than 20×104.

  1. Efficient H{sub 2}-producing photo-catalytic systems based on cyclo-metallated iridium- and tricarbonyl-rhenium-diimine photosensitizers and cobaloxime catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Fihri, A.; Artero, V.; Fontecave, M. [Univ Grenoble 1, Lab Chim et Biol Metaux, Grenoble (France); Fihri, A.; Artero, V.; Fontecave, M. [CNRS, UMR 5249, F-75700 Paris (France); Fihri, A.; Artero, V.; Fontecave, M. [CEA, DSV, iRTSV, F-38054 Grenoble 9 (France); Pereira, A. [CEA, DRT, Liten, DTNM, LTS, Grenoble (France)

    2008-07-01

    Quantum yield values up to 16% under visible irradiation associated with high turnover frequencies ({approx} 50 h{sup -1}) and stability (up to 273 turnovers), characterize the new photo-catalytic systems for hydrogen production, based on diimine derivatives of ruthenium, cyclo-metallated iridium or tricarbonyl-rhenium as photosensitizers and cobaloxime H{sub 2}-evolving catalytic centers, which are among the most efficient molecular systems reported so far and compete with some platinum-based systems. (authors)

  2. Synthesis, characterization and evaluation of CO-oxidation catalysts for high repetition rate CO2 TEA lasers

    Science.gov (United States)

    Moser, Thomas P.

    1990-06-01

    An extremely active class of noble metal catalysts supported on titania was developed and fabricated at Hughes for the recombination of oxygen (O2) and carbon monoxide (CO) in closed-cycle CO2 TEA lasers. The incipient wetness technique was used to impregnate titania and alumina pellets with precious metals including platinum and palladium. In particular, the addition of cerium (used as an oxygen storage promoter) produced an extremely active Pt/Ce/TiO2 catalyst. By comparison, the complementary Pt/Ce/ gamma-Al2O3 catalyst was considerably less active. In general, chloride-free catalyst precursors proved critical in obtaining an active catalyst while also providing uniform metal distributions throughout the support structure. Detailed characterization of the Pt/Ce/TiO2 catalyst demonstrated uniform dendritic crystal growth of the metals throughout the support. Electron spectroscopy for Chemical Analysis (ESCA) analysis was used to characterize the oxidation states of Pt, Ce and Ti. The performance of the catalysts was evaluated with an integral flow reactor system incorporating real time analysis of O2 and CO. With this system, the transient and steady-state behavior of the catalysts were evaluated. The kinetic evaluation was complemented by tests in a compact, closed-cycle Hughes CO2 TEA laser operating at a pulse repetition rate of 100 Hz with a catalyst temperature of 75 to 95 C. The Pt/Ce/TiO2 catalyst was compatible with a C(13)O(16)2 gas fill.

  3. MECHANICAL STRENGTH AND RELIABILITY OF SOLID CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    Yongdan Li; Dongfang Wu; Y.S. Lin

    2004-01-01

    The mechanical strength of solid catalysts is one of the key parameters for reliable and efficient performance of a fixed bed reactor. Some recent developments and their basic mechanics within this context are reviewed. The main concepts discussed are brittle fracture which leads to the mechanical failure of the catalyst pellets, measurement and statistical properties of the catalyst strength data, and mechanical reliability of the catalyst pellets and their packed bed. The scientific basis for the issues on the catalyst mechanical properties calls yet for further elucidation and advancement.

  4. WATER-GAS SHIFT KINETICS OVER IRON OXIDE CATALYSTS AT MEMBRANE REACTOR CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Carl R.F. Lund

    2002-08-02

    The kinetics of water-gas shift were studied over ferrochrome catalysts under conditions with high carbon dioxide partial pressures, such as would be expected in a membrane reactor. The catalyst activity is inhibited by increasing carbon dioxide partial pressure. A microkinetic model of the reaction kinetics was developed. The model indicated that catalyst performance could be improved by decreasing the strength of surface oxygen bonds. Literature data indicated that adding either ceria or copper to the catalyst as a promoter might impart this desired effect. Ceria-promoted ferrochrome catalysts did not perform any better than unpromoted catalyst at the conditions tested, but copper-promoted ferrochrome catalysts did offer an improvement over the base ferrochrome material. A different class of water-gas shift catalyst, sulfided CoMo/Al{sub 2}O{sub 3} is not affected by carbon dioxide and may be a good alternative to the ferrochrome system, provided other constraints, notably the requisite sulfur level and maximum temperature, are not too limiting. A model was developed for an adiabatic, high-temperature water-gas shift membrane reactor. Simulation results indicate that an excess of steam in the feed (three moles of water per mole of CO) is beneficial even in a membrane reactor as it reduces the rate of adiabatic temperature rise. The simulations also indicate that much greater improvement can be attained by improving the catalyst as opposed to improving the membrane. Further, eliminating the inhibition by carbon dioxide will have a greater impact than will increasing the catalyst activity (assuming inhibition is still operative). Follow-up research into the use of sulfide catalysts with continued kinetic and reactor modeling is suggested.

  5. Evaluation of nanostructured Pt-Ru catalyst for application in DMFC

    Energy Technology Data Exchange (ETDEWEB)

    Ocampo, A.L.; Gamboa, S.A. [Centro de Investigacion en Energia-UNAM, Morelos (Mexico); Sebastien, P.J. [Centro de Investigacion en Energia-UNAM, Morelos (Mexico)]|[Chiapas Politecnica Univ., Chiapas (Mexico); Morgado, J.; Montoya, J.A. [IMP, Eje Central Lazaro Cardenas, (Mexico); Savadogo, O. [Ecole Polytechnique, Montreal, PQ (Canada). Laboratoire d' electrochimie et de materiaux energetiques

    2006-07-01

    Slow methanol oxidation kinetics and the poisoning of the anode catalyst are the major factors that limit the performance of the direct methanol fuel cell (DMFC). Catalysts with higher catalytic activity are needed in order to overcome these challenges. Although platinum (Pt) is a good catalyst for methanol oxidation, it can be highly affected by carbon monoxide (CO) reaction intermediates. Superior catalytic activity occurs in Pt based alloys, such as platinum ruthenium (Pt-Ru), platinum molybdenum (Pt-Mo), platinum tin (Pt-Sn), and platinum osmium (Pt-Os). This is due to the bifunctional mechanism and/or by the electronic effect, which indicates a promotional effect of the alloyed metal on Pt. The most studied binary system is the Pt-Ru (ruthenium), which has shown the best catalytic activity. There are many factors that influence the physical properties and the electrochemical performance of the Pt-Ru catalyst. These include the preparation method; the atomic ratio between platinum and ruthenium; the nature of the catalyst support; and, an optional heat treatment. Other important factors such as the particle size, the morphology, the electrochemically active area, and the crystalline phase influence the physical properties. In this study, nanostructured Pt-Ru catalysts were fabricated and evaluated physicochemically and electrochemically for its use in direct methanol fuel cell (DMFC). The catalysts were synthesized from the carbonyl compounds of Pt and Ru via a pyrolysis-condensation reaction. The high resolution results showed a homogenous distribution of the nanostructured catalysts on Vulcan support. The catalyst was evaluated by XRD, HRTEM, electrochemical impedance spectroscopy and the methanol oxidation on the catalyst was studied using volt-amperometry. The performance of the catalyst was found to be similar or better than the commercial one. It was concluded that it is possible to synthesize Pt-Ru/C with good morphological characteristics and improve it

  6. 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

  7. Deactivation by carbon of iron catalysts for indirect liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, C.H.

    1990-10-11

    This report describes recent progress in a fundamental, three-year investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for Fischer-Tropsch (FT) synthesis, the objectives of which are: determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation over a range of CO concentrations, CO:H{sub 2} ratios, and temperatures; model the rates of deactivation of the same catalysts in fixed-bed reactors. During the thirteenth quarter design of software for a computer-automated reactor system to be used in the kinetic and deactivation studies was continued. Further progress was made toward the completion of the control language, control routines, and software for operating this system. Progress was also made on the testing of the system hardware and software. H{sub 2} chemisorption capacities and activity selectivity data were also measured for three iron catalysts promoted with 1% alumina. 47 refs., 8 figs., 1 tab.

  8. A trinuclear ruthenium complex as a highly efficient molecular catalyst for water oxidation.

    Science.gov (United States)

    Zhang, L L; Gao, Y; Liu, Z; Ding, X; Yu, Z; Sun, L C

    2016-03-01

    A trinuclear ruthenium complex, 3, was designed and synthesized with the ligand 2,2'-bipyridine-6,6'-dicarboxylic acid (bda) and we found that this complex could function as a highly efficient molecular catalyst for water oxidation in homogeneous systems. This trinuclear molecular water oxidation catalyst, 3, displayed much higher efficiencies in terms of turnover numbers and initial oxygen evolution rate than its counterparts, a binuclear catalyst, 2, and a mononuclear catalyst, 1, in both chemically driven and photochemically driven water oxidation based on either the whole catalytic molecules or just the active Ru centers. The reasons for the superior performance of catalyst 3 were discussed and we believe that multiple Ru centers in a single molecule are indeed beneficial for increasing the probability of the formation of O-O bonds through an intramolecular radical coupling pathway.

  9. Influence of Yttrium and Ytterbium on Reaction Performance of Platinum-Rhenium Reforming Catalyst

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The influence of yttrium and ytterbium on the catalytic performance of Pt-Re reforming cata-lysts was studied in a continuous flow pressurized microreactor-chromatograph system and pilot unit. Theresults of micro-reactor test showed that both yttrium and ytterbium could improve the selectivity of Pt-Recatalysts for the conversion ofn-heptane as well as MCP into aromatics, but also suppressed their activityas well. Pilot test results showed that yttrium and ytterbium enhanced both the selectivity and activity ofPt-Re catalysts for naphtha reforming. Yttrium showed more improvement than ytterbium. The perfor-mance difference between microreactor test and pilot test might be due to the difference in improvement ofcatalytic stability of yttrium or ytterbium modified Pt-Re catalysts. Yttrium and ytterbium improved thecoking resistance of yttrium or ytterbium modified Pt-Re catalysts. TEM determination results indicatedthat both yttrium and ytterbium had improved the thermal stability of Pt-Re catalysts.

  10. TEST REPORT OF MOBILE SOURCE EMISSIONS CONTROL DEVICES DONALDSON COMPANY INC.SERIES 6100 DIESEL OXIDATION CATALYST MUFFLER AND SPIRACLE CLOSED CRANKCASE FILTRATION SYSTEM

    Science.gov (United States)

    This report is on an environmental verification of the emissions characteristics of a Donaldson Corp. catalytic muffler and catalyic crankcase emissions control. It was found the systems reduced emissions.

  11. Solvent effects on Pt-Ru/C catalyst for methanol electro-oxidation

    Institute of Scientific and Technical Information of China (English)

    Jinwei Chen; Chunping Jiang; Hui Lu; Lan Feng; Xin Yang; Liangqiong Li; Ruilin Wang

    2009-01-01

    Alloying degree,particle size and the level of dispersion are the key structural parameters of Pt-Ru/C catalyst in fuel cells. Solvent(s) used in the preparation process can affect the particle size and alloying degree of the object substance,which lead to a great positive impact on its properties. In this work,three types of solvents and their mixtures were used in preparation of the Pt-Ru/C catalysts by chemical reduction of metal precursors with sodium borohydride at room temperature. The structure of the catalysts was characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The catalytic activity and stability for methanol electro-oxidation were studied by Cyclic Voltammetry (CV) and Chronoamperometry (CA). Pt-Ru/C catalyst prepared in H_2O or binary solvents of H_2O and isopropanol had large particle size and low alloying degree leading to low catalytic activity and less stability in methanol electro-oxidation. When tetrahydrofuran was added to the above solvent systems,Pt-Ru/C catalyst prepared had smaller particle size and higher alloying degree which resulted in better catalytic activity,lower onset and peak potentials,compared with the above catalysts. Moreover,the catalyst prepared in ternary solvents of isopropanol,water and tetrahydrofuran had the smallest particle size,and the high alloying degree and the dispersion kept unchanged. Therefore,this kind of catalyst showed the highest catalytic activity and good stability for methanol electro-oxidation.

  12. Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chunshan Song; Schobert, H.H.; Parfitt, D.P. [and others

    1997-11-01

    Development of new catalysts is a promising approach to more efficient coal liquefaction. It has been recognized that dispersed catalysts are superior to supported catalysts for primary liquefaction of coals, because the control of initial coal dissolution or depolymerization requires intimate contact between the catalyst and coal. This research is a fundamental and exploratory study on catalytic coal liquefaction, with the emphasis on exploring novel bimetallic dispersed catalysts for coal liquefaction and the effectiveness of temperature-programmed liquefaction using dispersed catalysts. The primary objective of this research was to explore novel bimetallic dispersed catalysts from organometallic molecular precursors, that could be used in low concentrations but exhibit relatively high activity for efficient hydroliquefaction of coals under temperature-programmed conditions. We have synthesized and tested various catalyst precursors in liquefaction of subbituminous and bituminous coals and in model compound studies to examine how do the composition and structure of the catalytic precursors affect their effectiveness for coal liquefaction under different reaction conditions, and how do these factors affect their catalytic functions for hydrogenation of polyaromatic hydrocarbons, for cleavage of C-C bonds in polycyclic systems such as 4-(1-naphthylmethyl)bibenzyl, for hydrogenolysis of C-O bond such as that in dinaphthylether, for hydrodeoxygenation of phenolic compounds and other oxygen-containing compounds such as xanthene, and for hydrodesulfurization of polycyclic sulfur compounds such as dibenzothiophene. The novel bimetallic and monometallic precursors synthesized and tested in this project include various Mo- and Fe-based compounds.

  13. Life Cycle Assessment of Biochar versus Metal Catalysts Used in Syngas Cleaning

    Directory of Open Access Journals (Sweden)

    Robert S. Frazier

    2015-01-01

    Full Text Available Biomass gasification has the potential to produce renewable fuels, chemicals and power at large utility scale facilities. In these plants catalysts would likely be used to reform and clean the generated biomass syngas. Traditional catalysts are made from transition metals, while catalysts made from biochar are being studied. A life cycle assessment (LCA study was performed to analyze the sustainability, via impact assessments, of producing a metal catalyst versus a dedicated biochar catalyst. The LCA results indicate that biochar has a 93% reduction in greenhouse gas (GHG emissions and requires 95.7% less energy than the metal catalyst to produce. The study also estimated that biochar production would also have fewer impacts on human health (e.g., carcinogens and respiratory impacts than the production of a metal catalyst. The possible disadvantage of biochar production in the ecosystem quality is due mostly to its impacts on agricultural land occupation. Sensitivity analysis was carried out to assess environmental impacts of variability in the two production systems. In the metal catalyst manufacture, the extraction and production of nickel (Ni had significant negative effects on the environmental impacts. For biochar production, low moisture content (MC, 9% and high yield type (8 tons/acre switchgrass appeared more sustainable.

  14. CO Selective Oxidation in Hydrogen-Rich Gas over Copper-Series Catalysts

    Institute of Scientific and Technical Information of China (English)

    Hanbo Zou; Xinfa Dong; Weiming Lin

    2005-01-01

    The performances of CO selective oxidation in hydrogen-rich gas over four catalytic systems of CuO/ZrO2, CuO/MnO2, CuO/CoO and CuO/CeO2 were compared. The reducibility of these catalysts and the effect of CuO and CeO2 molar ratio of CuO/CeO2 catalysts on the activity of selective CO oxidation are investigated by XRD and TPR methods. The results show that the catalysts with the exception of CuO/ZrO2 have the interactions between CuO and CoO, CeO2 or MnO2, which result in a decrease in the reduction temperature. Among the catalysts studied, CuO/ZrO2 catalyst shows the lowest catalytic activity while CuO/CeO2 catalyst exhibits the best catalytic performance. The CuO(10%)/CeO2 catalyst attains the highest CO conversion and selectivity at 140 and 160 ℃. The addition of 9% H2O in the reactant feed decreases the activity of CuO/CeO2 catalyst but increases its CO selectivity.

  15. 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.)

  16. Advances in the development of new catalysts for ethylene and α-olefin polymerisation

    Science.gov (United States)

    Ivanchev, Sergei S.

    2007-07-01

    The role of catalyst systems in the perfection of polymerisation processes and the improvement of the performance characteristics of polyethylene and other polyolefins is considered. The scope of application of post-metallocene catalysts based on transition metal α-diimine, bis(imino)pyridine and phenoxy imine complexes designed in the last decade is analysed. The structures of complexes depending on the type of ligands are described systematically. The development of research into these catalyst systems is discussed, the optimal structures as regards the activity and selectivity are mentioned, and the mechanism of their action and the prospects for industrial use are demonstrated.

  17. Activity of platinum/carbon and palladium/carbon catalysts promoted by Ni2 P in direct ethanol fuel cells.

    Science.gov (United States)

    Li, Guoqiang; Feng, Ligang; Chang, Jinfa; Wickman, Björn; Grönbeck, Henrik; Liu, Changpeng; Xing, Wei

    2014-12-01

    Ethanol is an alternative fuel for direct alcohol fuel cells, in which the electrode materials are commonly based on Pt or Pd. Owing to the excellent promotion effect of Ni2 P that was found in methanol oxidation, we extended the catalyst system of Pt or Pd modified by Ni2 P in direct ethanol fuel cells. The Ni2 P-promoted catalysts were compared to commercial catalysts as well as to reference catalysts promoted with only Ni or only P. Among the studied catalysts, Pt/C and Pd/C modified by Ni2 P (30 wt %) showed both the highest activity and stability. Upon integration into the anode of a homemade direct ethanol fuel cell, the Pt-Ni2 P/C-30 % catalyst showed a maximum power density of 21 mW cm(-2) , which is approximately two times higher than that of a commercial Pt/C catalyst. The Pd-Ni2 P/C-30 % catalyst exhibited a maximum power density of 90 mW cm(-2) . This is approximately 1.5 times higher than that of a commercial Pd/C catalyst. The discharge stability on both two catalysts was also greatly improved over a 12 h discharge operation.

  18. Studies in transition metal chemistry ; VI. Soluble Ziegler-type catalysts based on vanadium, part II

    NARCIS (Netherlands)

    Liefde Meijer, H.J. de; Hurk, J.W.G. van den; Kerk, G.J.M. van der

    1966-01-01

    Spectrophotometric measurements in the visible region on soluble catalyst systems prepared from (i) vanadium tetrachloride, aluminium bromide and tetraphenyltin and (ii) vanadium tetrachloride or vanadium oxytrichloride and ethylaluminium dihalides are reported. The formation of hydrocarbonsoluble i

  19. Biodiesel production using heterogeneous catalysts.

    Science.gov (United States)

    Semwal, Surbhi; Arora, Ajay K; Badoni, Rajendra P; Tuli, Deepak K

    2011-02-01

    The production and use of biodiesel has seen a quantum jump in the recent past due to benefits associated with its ability to mitigate greenhouse gas (GHG). There are large number of commercial plants producing biodiesel by transesterification of vegetable oils and fats based on base catalyzed (caustic) homogeneous transesterification of oils. However, homogeneous process needs steps of glycerol separation, washings, very stringent and extremely low limits of Na, K, glycerides and moisture limits in biodiesel. Heterogeneous catalyzed production of biodiesel has emerged as a preferred route as it is environmentally benign needs no water washing and product separation is much easier. The present report is review of the progress made in development of heterogeneous catalysts suitable for biodiesel production. This review shall help in selection of suitable catalysts and the optimum conditions for biodiesel production.

  20. Co-Production of Electricity and Hydrogen Using a Novel Iron-based Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Hilaly, Ahmad; Georgas, Adam; Leboreiro, Jose; Arora, Salil; Head, Megann; Trembly, Jason; Turk, Brian; Gupta, Raghubir

    2011-09-30

    The primary objective of this project was to develop a hydrogen production technology for gasification applications based on a circulating fluid-bed reactor and an attrition resistant iron catalyst. The work towards achieving this objective consisted of three key activities: • Development of an iron-based catalyst suitable for a circulating fluid-bed reactor • Design, construction, and operation of a bench-scale circulating fluid-bed reactor system for hydrogen production • Techno-economic analysis of the steam-iron and the pressure swing adsorption hydrogen production processes. This report describes the work completed in each of these activities during this project. The catalyst development and testing program prepared and iron-based catalysts using different support and promoters to identify catalysts that had sufficient activity for cyclic reduction with syngas and steam oxidation and attrition resistance to enable use in a circulating fluid-bed reactor system. The best performing catalyst from this catalyst development program was produced by a commercial catalyst toll manufacturer to support the bench-scale testing activities. The reactor testing systems used during material development evaluated catalysts in a single fluid-bed reactor by cycling between reduction with syngas and oxidation with steam. The prototype SIP reactor system (PSRS) consisted of two circulating fluid-bed reactors with the iron catalyst being transferred between the two reactors. This design enabled demonstration of the technical feasibility of the combination of the circulating fluid-bed reactor system and the iron-based catalyst for commercial hydrogen production. The specific activities associated with this bench-scale circulating fluid-bed reactor systems that were completed in this project included design, construction, commissioning, and operation. The experimental portion of this project focused on technical demonstration of the performance of an iron-based catalyst and a

  1. Alternative alkali resistant deNOx catalysts

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Kristensen, Steffen Buus; Due-Hansen, Johannes;

    2012-01-01

    Alternative alkali resistant deNOx catalysts were prepared using three different supports ZrO2, TiO2 and Mordenite zeolite. The majority of the catalysts were prepared by incipient wetness impregnation of a commercial support, with vanadium, copper or iron precursor, one catalyst was prepared...... by onepot sol–gel method. All catalysts were characterized by BET, XRPD and NH3-TPD. Initial SCR activities of 8 out of 9 catalysts showed higher NO conversion at least at one temperature in the temperature range 300–500 ◦C compared to the conventional V2O5-WO3/TiO2 catalyst. After potassium poisoning (100......–130 µmol of K/g of catalyst) the relative drop in SCR activity and acidity was lower for all the alternative catalysts compared to the industrial V2O5-WO3/TiO2 catalyst. Furthermore, Cu/MOR and Nano-V2O5/Sul-TiO2 catalysts showed 8–16 times higher SCR activities than the conventional even after high...

  2. Hydrocarbon conversion process and catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hoek, A.; Huizinga, T.; Maxwell, I.E.

    1990-05-15

    This patent describes a catalyst composition. It comprises: a modified Y zeolite having a unit cell size below about 24.45 {angstrom}, a degree of crystallinity which is at least retained at increasing SiO{sub 2}/Al{sub 2}O{sub 3} molar ratios, a SiO{sub 2}/Al{sub 2}O{sub 3} molar ratio between about 8 to about 15, a water adsorption capacity at (25{degree}C and a p/p{sub {ital o}} value of 0.2) of between about 10--15% by weight of modified zeolite and a pore volume of at lest about 0.25 ml/g. Between about 10 to about 40% of the total pore volume is made up of pores having a diameter of at least about 8 nm; an amorphous cracking component comprising a silica-alumina containing 50--95% by weight of silica; a binder comprising alumina; from about 0.05 to about 10 percent by weight of nickel and from about 2 to about 40 percent by weight of tungsten, calculated as metals per 100 parts by weight of total catalyst. The modified Y zeolite and amorphous cracking component comprises about 60--85% by weight of the total catalyst, the binder comprises about 15--40% by weight of the total catalyst and the amount of modified Y zeolite ranges between about 10--75% of the combined amount of modified Y zeolite and amorphous cracking component.

  3. NMR study of complexation in the catalyst - hydroperoxide, catalyst - alcohol, and catalyst - olefin - hydroperoxide systems

    Energy Technology Data Exchange (ETDEWEB)

    Azhikova, R.M.; Syroezhko, A.M.; Proskuryakov, V.A.

    1989-01-01

    On the basis of paramagnetic shifts and the broadening of NMR lines of hydroperoxide protons of cyclohexyl- and 1-methylcyclohexyl peroxides in haptane solution containing Mo(O) hexacarbonyl or Co(II) acetylacetonate, the authors have determined the heats of complexation and the lifetimes of hydroperoxide ligands in the metal - complex-former coordination sphere, and the activation energies of their emergence from the coordination sphere. They have determined the distances from the complex former of the central metal to the hydroxyl protons of the ligand (hydroperoxide, alcohol), and the hyperfine electron - nucleus interaction constants for the ligand hydroxyl protons in the complex. Molybdenum hexacarbonyl forms labile outer-sphere complexes with hydroperoxides and alcohols. However Co(II) acetylacetonate forms complexes that are stronger and intermediate between inner-sphere and outer-sphere complexes.

  4. Sulfiding behavior of iron based coal liquefaction catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Ikenaga, N.; Taniguchi, H.; Watanabe, A.; Suzuki, T. [Kansai University, Osaka (Japan). Dept. of Chemical Engineering

    2000-03-01

    In order to understand the transformation mechanisms of iron-sulfur catalyst systems to pyrrhotite, the iron catalysts ({gamma}-FeOOH, {alpha}-FeOOH, Fe(CO){sub 5} and Fe{sub 3}(CO){sub 12}) and sulfur compounds (S and H{sub 2}S) were treated at 150-420{degree}C with or without an activated carbon, and then subjected to XRD and XPS analyses. Pyrrhotite (Fe{sub 1-x}S) was the major phase above 200{degree}C in the XRD profiles of all iron-sulfur catalyst systems. However, the formation of pyrite (FeS{sub 2}) from {gamma}-FeOOH and {gamma}-FeOOH on the catalyst surface was observed at 150-325{degree}C by XPS analyses. This result seems to indicate that active species (Fe{sub 1-x}S) would be transformed through FeS{sub 2} as an intermediate, but iron carbonyl complexes were directly transformed into pyrrhotite without the formation of FeS{sub 2}. 28 refs., 8 figs., 1 tab.

  5. Monodisperse Platinum and Rhodium Nanoparticles as Model Heterogeneous Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grass, Michael Edward [Univ. of California, Berkeley, CA (United States)

    2008-09-01

    Model heterogeneous catalysts have been synthesized and studied to better understand how the surface structure of noble metal nanoparticles affects catalytic performance. In this project, monodisperse rhodium and platinum nanoparticles of controlled size and shape have been synthesized by solution phase polyol reduction, stabilized by polyvinylpyrrolidone (PVP). Model catalysts have been developed using these nanoparticles by two methods: synthesis of mesoporous silica (SBA-15) in the presence of nanoparticles (nanoparticle encapsulation, NE) to form a composite of metal nanoparticles supported on SBA-15 and by deposition of the particles onto a silicon wafer using Langmuir-Blodgett (LB) monolayer deposition. The particle shapes were analyzed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM) and the sizes were determined by TEM, X-ray diffraction (XRD), and in the case of NE samples, room temperature H2 and CO adsorption isotherms. Catalytic studies were carried out in homebuilt gas-phase reactors. For the nanoparticles supported on SBA-15, the catalysts are in powder form and were studied using the homebuilt systems as plug-flow reactors. In the case of nanoparticles deposited on silicon wafers, the same systems were operated as batch reactors. This dissertation has focused on the synthesis, characterization, and reaction studies of model noble metal heterogeneous catalysts. Careful control of particle size and shape has been accomplished though solution phase synthesis of Pt and Rh nanoparticles in order to elucidate further structure-reactivity relationships in noble metal catalysis.

  6. Multistep continuous-flow synthesis of (R)- and (S)-rolipram using heterogeneous catalysts

    Science.gov (United States)

    Tsubogo, Tetsu; Oyamada, Hidekazu; Kobayashi, Shū

    2015-04-01

    Chemical manufacturing is conducted using either batch systems or continuous-flow systems. Flow systems have several advantages over batch systems, particularly in terms of productivity, heat and mixing efficiency, safety, and reproducibility. However, for over half a century, pharmaceutical manufacturing has used batch systems because the synthesis of complex molecules such as drugs has been difficult to achieve with continuous-flow systems. Here we describe the continuous-flow synthesis of drugs using only columns packed with heterogeneous catalysts. Commercially available starting materials were successively passed through four columns containing achiral and chiral heterogeneous catalysts to produce (R)-rolipram, an anti-inflammatory drug and one of the family of γ-aminobutyric acid (GABA) derivatives. In addition, simply by replacing a column packed with a chiral heterogeneous catalyst with another column packed with the opposing enantiomer, we obtained antipole (S)-rolipram. Similarly, we also synthesized (R)-phenibut, another drug belonging to the GABA family. These flow systems are simple and stable with no leaching of metal catalysts. Our results demonstrate that multistep (eight steps in this case) chemical transformations for drug synthesis can proceed smoothly under flow conditions using only heterogeneous catalysts, without the isolation of any intermediates and without the separation of any catalysts, co-products, by-products, and excess reagents. We anticipate that such syntheses will be useful in pharmaceutical manufacturing.

  7. Systems and methods for solar energy storage, transportation, and conversion utilizing photochemically active organometallic isomeric compounds and solid-state catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Vollhardt, K. Peter C.; Segalman, Rachel A; Majumdar, Arunava; Meier, Steven

    2015-02-10

    A system for converting solar energy to chemical energy, and, subsequently, to thermal energy includes a light-harvesting station, a storage station, and a thermal energy release station. The system may include additional stations for converting the released thermal energy to other energy forms, e.g., to electrical energy and mechanical work. At the light-harvesting station, a photochemically active first organometallic compound, e.g., a fulvalenyl diruthenium complex, is exposed to light and is photochemically converted to a second, higher-energy organometallic compound, which is then transported to a storage station. At the storage station, the high-energy organometallic compound is stored for a desired time and/or is transported to a desired location for thermal energy release. At the thermal energy release station, the high-energy organometallic compound is catalytically converted back to the photochemically active organometallic compound by an exothermic process, while the released thermal energy is captured for subsequent use.

  8. Mussel-inspired Functionalization of Cotton for Nano-catalyst Support and Its Application in a Fixed-bed System with High Performance

    Science.gov (United States)

    Xi, Jiangbo; Xiao, Junwu; Xiao, Fei; Jin, Yunxia; Dong, Yue; Jing, Feng; Wang, Shuai

    2016-02-01

    Inspired by the composition of adhesive and reductive proteins secreted by marine mussels, polydopamine (PDA) was used to coat cotton microfiber (CMF), and then acted as reducing agent for the growth of Pd nanoparticles on PDA coated CMF (PDA@CMF) composites. The resultant CMF@PDA/Pd composites were then packed in a column for the further use in fixed-bed system. For the catalysis of the reduction of 4-nitrophenol, the flow rate of the 4-aminophenol solution (0.5 mM) was as high as 60 mL/min. The obtained fixed-bed system even exhibited superior performance to conventional batch reaction process because it greatly facilitated the efficiency of the catalytic fibers. Consequently, its turnover frequency (TOF) was up to 1.587 min-1, while the TOF in the conventional batch reaction was 0.643 min-1. The catalytic fibers also showed good recyclability, which can be recycled for nine successive cycles without a loss of activity. Furthermore, the catalytic system based on CMF@PDA/Pd can also be applied for Suzuki coupling reaction with the iodobenzene conversion up to 96.7%. The strategy to prepare CMF@PDA/Pd catalytic fixed bed was simple, economical and scalable, which can also be applied for coating different microfibers and loading other noble metal nanoparticles, was amenable for automated industrial processes.

  9. Final technical report. Bimetallic complexes as methanol oxidation catalysts

    Energy Technology Data Exchange (ETDEWEB)

    McElwee-White, Lisa

    2002-01-21

    Our work on the electrocatalyzed oxidation of methanol was initially motivated by the interest in methanol as an anodic reactant in fuel cells. The literature on electrochemical oxidation of alcohols can be roughly grouped into two sets: fuel cell studies and inorganic chemistry studies. Work on fuel cells primarily focuses on surface-catalyzed oxidation at bulk metal anodes, usually Pt or Pt/Ru alloys. In the surface science/electrochemistry approach to these studies, single molecule catalysts are generally not considered. In contrast, the inorganic community investigates the electrooxidation of alcohols in homogeneous systems. Ruthenium complexes have been the most common catalysts in these studies. The alcohol substrates are typically either secondary alcohols (e.g., isopropanol) such that the reaction stops after 2 e{sup -} oxidation to the aldehyde and 4 e{sup -} oxidation to the carboxylic acid can be observed. Methanol, which can also undergo 6 e{sup -} oxidation to CO{sub 2}, rarely appears in the homogeneous catalysis studies. Surface studies have shown that two types of metal centers with different functions result in more effective catalysts than a single metal; however, application of this concept to homogeneous systems has not been demonstrated. The major thrust of the work is to apply this insight from the surface studies to homogeneous catalysis. Even though homogeneous systems would not be appropriate models for active sites on Pt/Ru anodes, it is possible that heterobimetallic catalysts could also utilize two metal centers for different roles. Starting from that perspective, this work involves the preparation and investigation of heterobinuclear catalysts for the electrochemical oxidation of methanol.

  10. Rational approach to polymer-supported catalysts: synergy between catalytic reaction mechanism and polymer design.

    Science.gov (United States)

    Madhavan, Nandita; Jones, Christopher W; Weck, Marcus

    2008-09-01

    Supported catalysis is emerging as a cornerstone of transition metal catalysis, as environmental awareness necessitates "green" methodologies and transition metal resources become scarcer and more expensive. Although these supported systems are quite useful, especially in their capacity for transition metal catalyst recycling and recovery, higher activity and selectivity have been elusive compared with nonsupported catalysts. This Account describes recent developments in polymer-supported metal-salen complexes, which often surpass nonsupported analogues in catalytic activity and selectivity, demonstrating the effectiveness of a systematic, logical approach to designing supported catalysts from a detailed understanding of the catalytic reaction mechanism. Over the past few decades, a large number of transition metal complex catalysts have been supported on a variety of materials ranging from polymers to mesoporous silica. In particular, soluble polymer supports are advantageous because of the development of controlled and living polymerization methods that are tolerant to a wide variety of functional groups, including controlled radical polymerizations and ring-opening metathesis polymerization. These methods allow for tuning the density and structure of the catalyst sites along the polymer chain, thereby enabling the development of structure-property relationships between a catalyst and its polymer support. The fine-tuning of the catalyst-support interface, in combination with a detailed understanding of catalytic reaction mechanisms, not only permits the generation of reusable and recyclable polymer-supported catalysts but also facilitates the design and realization of supported catalysts that are significantly more active and selective than their nonsupported counterparts. These superior supported catalysts are accessible through the optimization of four basic variables in their design: (i) polymer backbone rigidity, (ii) the nature of the linker, (iii) catalyst

  11. Ni-Cu Hydrotalcite-Derived Mixed Oxides as Highly Selective and Stable Catalysts for the Synthesis of β-Branched Bioalcohols by the Guerbet Reaction.

    Science.gov (United States)

    Hernández, Willinton Y; De Vlieger, Kevin; Van Der Voort, Pascal; Verberckmoes, An

    2016-11-23

    A series of Ni-Cu hydrotalcite-derived mixed oxides have been synthesized and evaluated as heterogeneous catalysts for the dimerization of linear aliphatic alcohols to afford β-branched Guerbet alcohols. The use of the hydrotalcite-structured catalyst precursor highly favors the catalyst stability. This Cu/Ni catalyst has an enhanced reducibility of Ni(2+) species under reaction conditions, favoring the hydrogen transfer and hydrogenation capacity of the catalyst system. Catalytic results are reported for C8 , mixed C8 /C10 , and C18 alcohol feeds, with full conversions and Guerbet product purities of 72.5-96 %.

  12. Mussel-inspired Functionalization of Cotton for Nano-catalyst Support and Its Application in a Fixed-bed System with High Performance

    OpenAIRE

    Jiangbo Xi; Junwu Xiao; Fei Xiao; Yunxia Jin; Yue Dong; Feng Jing; Shuai Wang

    2016-01-01

    Inspired by the composition of adhesive and reductive proteins secreted by marine mussels, polydopamine (PDA) was used to coat cotton microfiber (CMF), and then acted as reducing agent for the growth of Pd nanoparticles on PDA coated CMF (PDA@CMF) composites. The resultant CMF@PDA/Pd composites were then packed in a column for the further use in fixed-bed system. For the catalysis of the reduction of 4-nitrophenol, the flow rate of the 4-aminophenol solution (0.5 mM) was as high as 60 mL/min....

  13. Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts

    Directory of Open Access Journals (Sweden)

    R. Prasad

    2011-05-01

    Full Text Available CuO-CeO2 systems have been proposed as a promising catalyst for low temperature diesel-soot oxidation. CuO-CeO2 catalysts prepared by various methods were examined for air oxidation of the soot in a semi batch tubular flow reactor. The air oxidation of soot was carried out under tight contact with soot/catalyst ratio of 1/10. Air flow rate was 150 ml/min, soot-catalyst mixture was 110 mg, heating rate was 5 0C/min. Prepared catalysts were calcined at 500 0C and their stability was examined by further heating to 800 0C for 4 hours. It was found that the selectivity of all the catalysts was nearly 100% to CO2 production. It was observed that the activity and stability of the catalysts greatly influenced by the preparation methods. The strong interaction between CuO and CeO2 is closely related to the preparation route that plays a crucial role in the soot oxidation over the CuO-CeO2 catalysts. The ranking order of the preparation methods of the catalysts in the soot oxidation performance is as follows: sol-gel > urea nitrate combustion > Urea gelation method > thermal decomposition > co-precipitation. Copyright © 2011 BCREC UNDIP. All rights reserved.(Received: 27th June 2010, Revised: 7th August 2010; Accepted: 13rd October 2010[How to Cite: R. Prasad, V.R. Bella. (2011. Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts. Bulletin of Chemical Reaction Engineering and Catalysis, 6(1: 15-21. doi:10.9767/bcrec.6.1.822.15-21][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.1.822.15-21 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/822 | View in 

  14. Evaluation of Promoters for Rhodium-Based Catalysts for Mixed Alcohol Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, Mark A.; White, James F.; Gray, Michel J.; Stevens, Don J.

    2008-12-08

    Pacific Northwest National Laboratory (PNNL) and National Renewable Energy Laboratory (NREL) are conducting research to investigate the feasibility of producing mixed alcohols from biomass-derived synthesis gas (syngas). PNNL is tasked with obtaining commercially-available catalysts or preparing promising mixed-alcohol catalysts and screening them in a laboratory-scale reactor system. Commercially-available catalysts and the most promising experimental catalysts are provided to NREL for testing using a slipstream from a pilot-scale biomass gasifier. A total of 28 tests were conducted to evaluate 22 different promoters as well as an unpromoted catalyst. The following general trends were observed for the test results: • The highest carbon selectivity to C2+ oxygenates occurred at the lowest reaction temperatures and accompanying lowest space time yields (STYs). • The lowest carbon selectivity to C2+ oxygenates occurred at the highest reaction temperatures because of high carbon conversion to hydrocarbons. • The highest C2+-oxygenate STYs occurred between 300°C and 325°C, with the gas hourly space velocity (GHSV) adjusted when necessary to maintain carbon conversion ranges between ~ 30 and 40 percent. Higher carbon selectivity to hydrocarbons at higher temperatures resulted in lower C2+-oxygenate STYs. • When catalysts were heated to between 300°C and 325°C the catalysts showed evidence of some deactivation with respect to C2+ oxygenate productivity, accompanied by reduced chain growth for the hydrocarbon products. The degree of deactivation and the temperature at which it occurred varied between the different catalysts tested. Of all of the catalysts evaluated, the Li-promoted catalysts had the highest carbon selectivity to C2+ oxygenates (47 percent) under the conditions at which the maximum C2+-oxygenate STYs were obtained.

  15. Synthesis and characterization of mesoporous hydrocracking catalysts

    Science.gov (United States)

    Munir, D.; Usman, M. R.

    2016-08-01

    Mesoporous catalysts have shown great prospective for catalytic reactions due to their high surface area that aids better distribution of impregnated metal. They have been found to contain more adsorption sites and controlled pore diameter. Hydrocracking, in the presence of mesoporous catalyst is considered more efficient and higher conversion of larger molecules is observed as compared to the cracking reactions in smaller microporous cavities of traditional zeolites. In the present study, a number of silica-alumina based mesoporous catalysts are synthesized in the laboratory. The concentration and type of surfactants and quantities of silica and alumina sources are the variables studied in the preparation of catalyst supports. The supports prepared are well characterized using SEM, EDX, and N2-BET techniques. Finally, the catalysts are tested in a high pressure autoclave reactor to study the activity and selectivity of the catalysts for the hydrocracking of a model mixture of plastics comprising of LDPE, HDPE, PP, and PS.

  16. Organic synthesis with olefin metathesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grubbs, R.H. [California Institute of Technology, Pasadena, CA (United States)

    1995-12-31

    Over the past nine years, early transition metal catalysts for the ring opening metathesis polymerization of cyclic olefins have been developed. These catalysts are simple organometallic complexes containing metal carbon multiple bonds that in most cases polymerize olefins by a living process. These catalysts have been used to prepare a family of near monodispersed and structurally homogeneous polymers. A series of group VII ROMP catalysts that allow a wide range of functionality to be incorporated into the polymer side chains have been prepared. The most important member of this family of complexes are the bisphosphinedihalo-ruthenium carbene complexes. These polymerization catalysts can also be used in the synthesis of fine chemicals by ring closing (RCM) and vinyl coupling reactions. The availability of the group VII catalysts allow metathesis to be carried out on highly functionalized substrates such as polypeptides and in unusual environments such as in aqueous emulsions.

  17. EFFECTS OF CATALYST MORPHOLOGY ON HYDROTREATING REACTIONS

    Directory of Open Access Journals (Sweden)

    TYE CHING THIAN

    2008-08-01

    Full Text Available Due to the new environmental regulations for fuel quality, refineries need to process cleaner fuel. This requires an improvement in performance of hydrotreating catalysts. Improvements in catalyst activity require knowledge of the relationships between catalyst morphology and activity. Molybdenum sulfide, the generally agreed catalysts that give the best performance in hydrocracking and hydrotreating was investigated for its morphology effects on hydrotreating reactions. Three types of MoS2 catalysts with different morphology were studied. They are crystalline MoS2, exfoliated MoS2 and MoS2 derived from a precursor, molybdenum naphthenate. Exfoliated MoS2 with minimal long range order, with much higher rim edges has shown relative higher hydrogenation activity. Generally, results of MoS2 catalyst activities in hydrogenation, hydrodesulfurization, hydrodenitrogenation and hydrideoxy¬gena¬tion are in agreement with the rim-edge model.

  18. Liquid-phase non-thermal plasma-prepared N-doped TiO(2) for azo dye degradation with the catalyst separation system by ceramic membranes.

    Science.gov (United States)

    Cheng, Hsu-Hui; Chen, Shiao-Shing; Cheng, Yi-Wen; Tseng, Wei-Lun; Wang, Yi-Hui

    2010-01-01

    This study strived to improve the photocatalytic activity by using liquid-phase non-thermal plasma (LPNTP) technology for preparing N-doping TiO(2) as well as to separate/recover the N-dope TiO(2) particles by using ceramic ultrafiltration membrane process. The yellow color N-doped TiO(2) photocatalysts, obtained through the LPNTP process, were characterized with UV-Vis spectroscopy, X-ray diffraction (XRD), and electron spectroscopy for chemical analysis (ESCA). The UV-Vis spectrum of N-doped TiO(2) showed that the absorption band was shifted to 439 nm and the band gap was reduced to 2.82 eV. The structure analysis of XRD spectra showed that the peak positions and the crystal structure remained unchanged as anatase after plasma-treating at 13.5 W for 40 min. The photocatalytic activity of N-doped TiO(2) was evaluated by azo dyes under visible light, and 63% of them was degraded after 16 hours in a continuous-flow photocatalytic system. For membrane separation/recover system, the recovery efficiency reached 99.5% after the ultrafiltration had been carried out for 90 min, and the result indicated that the photocatalyst was able to be separated/recovered completely.

  19. Biomimetic catalysts responsive to specific chemical signals

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yan [Iowa State Univ., Ames, IA (United States)

    2015-03-04

    Part 1. Design of Biomimetic Catalysts Based on Amphiphilic Systems The overall objective of our research is to create biomimetic catalysts from amphiphilic molecules. More specifically, we aim to create supramolecular systems that can be used to control the microenvironment around a catalytic center in a biomimetic fashion and apply the learning to construct supramolecular catalysts with novel functions found in enzymatic catalysts. We have prepared synthetic molecules (i.e., foldamers) that could fold into helical structures with nanometer-sized internal hydrophilic cavities. Cavities of this size are typically observed only in the tertiary and quaternary structures of proteins but were formed in our foldamer prepared in just a few steps from the monomer. Similar to many proteins, our foldamers displayed cooperativity in the folding/unfolding equilibrium and followed a two-state conformational transition. In addition, their conformational change could be triggered by solvent polarity, pH, or presence of metal ions and certain organic molecules. We studied their environmentally dependent conformational changes in solutions, surfactant micelles, and lipid bilayer membranes. Unlike conventional rigid supramolecular host, a foldamer undergoes conformational change during guest binding. Our study in the molecular recognition of an oligocholate host yielded some extremely exciting results. Cooperativity between host conformation and host–guest interactions was found to “magnify” weak binding interactions. In other words, since binding affinity is determined by the overall change of free energy during the binding, guest-induced conformational change of the host, whether near or far from the binding site, affects the binding. This study has strong implications in catalysis because enzymes have been hypothesized to harvest similar intramolecular forces to strengthen their binding with the transition state of an enzyme-catalyzed reaction. The supramolecular and

  20. LDRD final report on new homogeneous and supported oligomerization catalysts (LDRD 42461).

    Energy Technology Data Exchange (ETDEWEB)

    Hascall, Anthony G.; Kemp, Richard Alan

    2004-11-01

    The overall purpose of this LDRD is multifold. First, we are interested in preparing new homogeneous catalysts that can be used in the oligomerization of ethylene and in understanding commercially important systems better. Second, we are interested in attempting to support these new homogeneous catalysts in the pores of nano- or mesoporous materials in order to force new and unusual distributions of a-olefins to be formed during the oligomerization. Thus the overall purpose is to try to prepare new catalytic species and to possibly control the active site architecture in order to yield certain desired products during a catalytic reaction, much like nature does with enzymes. In order to rationally synthesize catalysts it is imperative to comprehend the function of the various components of the catalyst. In heterogeneous systems, it is of utmost importance to know how a support interacts with the active site of the catalyst. In fact, in the catalysis world this lack of fundamental understanding of the relationship between active site and support is the single largest reason catalysis is considered an 'empirical' or 'black box' science rather than a well-understood one. In this work we will be preparing novel ethylene oligomerization catalysts, which are normally P-O chelated homogeneous complexes, with new ligands that replace P with a stable carbene. We will also examine a commercially catalyst system and investigate the active site in it via X-ray crystallography. We will also attempt to support these materials inside the pores of nano- and mesoporous materials. Essentially, we will be tailoring the size and scale of the catalyst active site and its surrounding environment to match the size of the molecular product(s) we wish to make. The overall purpose of the study will be to prepare new homogeneous catalysts, and if successful in supporting them to examine the effects that steric constraints and pore structures can have on growing oligomer

  1. Methane Tri-reforming over nickel catalysts

    OpenAIRE

    García Vargas, José Manuel

    2014-01-01

    The present work is part of a research program carried out in the Department of Chemical Engineering at the University of Castilla-La Mancha, focused in the preparation, characterization and evaluation of catalysts that can be applied in industrially relevant reactions. In this way, the PhD work reported here was aimed to study and improve nickel catalysts applied to the tri-reforming process, evaluating the role of support, precursor and promoter and optimizing the catalyst preparation. Furt...

  2. Oxidation catalysts on alkaline earth supports

    Science.gov (United States)

    Mohajeri, Nahid

    2017-03-21

    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  3. Oxidation catalysts on alkaline earth supports

    Energy Technology Data Exchange (ETDEWEB)

    Mohajeri, Nahid

    2017-03-21

    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  4. Molecular catalysts structure and functional design

    CERN Document Server

    Gade, Lutz H

    2014-01-01

    Highlighting the key aspects and latest advances in the rapidly developing field of molecular catalysis, this book covers new strategies to investigate reaction mechanisms, the enhancement of the catalysts' selectivity and efficiency, as well as the rational design of well-defined molecular catalysts. The interdisciplinary author team with an excellent reputation within the community discusses experimental and theoretical studies, along with examples of improved catalysts, and their application in organic synthesis, biocatalysis, and supported organometallic catalysis. As a result, readers wil

  5. POLYMER-SUPPORTED LEWIS ACID CATALYSTS. VI. POLYSTYRENE-BONDED STANNIC CHLORIDE CATALYST

    Institute of Scientific and Technical Information of China (English)

    RAN Ruicheng; FU Diankui

    1991-01-01

    A polystyrene-bonded stannic chloride catalyst was synthesized by the method of lithium polystyryl combined with stannic chloride. This catalyst is a polymeric organometallic compound containing 0.25 mmol Sn(IV)/g catalyst. The catalyst showed sufficient stability and catalytic activity in organic reaction such as esterification, acetalation and ketal formation, and it could be reused many times without losing its catalytic activity.

  6. Silica deactivation of bead VOC catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Libanati, C.; Pereira, C.J. [Research Division, W. R. Grace and Co., Columbia, MD (United States); Ullenius, D.A. [Grace TEC Systems, De Pere, WI (United States)

    1998-01-15

    Catalytic oxidation is a key technology for controlling the emissions of Volatile Organic Compounds (VOCs) from industrial plants. The present paper examines the deactivation by silica of bead VOC catalysts in a flexographic printing application. Post mortem analyses of field-aged catalysts suggest that organosilicon compounds contained in the printing ink diffuse into the catalyst and deposit as silica particles in the micropores. Laboratory activity evaluation of aged catalysts suggests that silica deposition is non-selective and that silica masks the noble metal active site

  7. Nanoparticular metal oxide/anatase catalysts

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention concerns a method of preparation of nanoparticular metal oxide catalysts having a narrow particle size distribution. In particular, the invention concerns preparation of nanoparticular metal oxide catalyst precursors comprising combustible crystallization seeds upon which...... the catalyst metai oxide is co-precipitated with the carrier metal oxide, which crystallization seeds are removed by combustion in a final calcining step. The present invention also concerns processes wherein the nanoparticular metal oxide catalysts of the invention are used, such as SCR (deNOx) reactions...

  8. The development of aqueous transfer hydrogenation catalysts.

    Science.gov (United States)

    Robertson, Andrew; Matsumoto, Takahiro; Ogo, Seiji

    2011-10-28

    This review discusses the development of aqueous phase, homogeneous, transfer hydrogenation catalysis. Transfer hydrogenation catalysts, based on Ru, Ir and Rh, reduce organic substrates in water by assisting the transfer of hydrogen from simple donor species. These catalysts are expected to have significant benefits when compared with organic phase catalysts, including greater activity, greater selectivity and smaller environmental impact. They will therefore be expected to make a significant contribution to homogeneous catalysis and 'green chemistry'. Here, we comprehensively examine these catalysts, paying special attention to structural features.

  9. Nitrogen oxides storage catalysts containing cobalt

    Science.gov (United States)

    Lauterbach, Jochen; Snively, Christopher M.; Vijay, Rohit; Hendershot, Reed; Feist, Ben

    2010-10-12

    Nitrogen oxides (NO.sub.x) storage catalysts comprising cobalt and barium with a lean NO.sub.x storage ratio of 1.3 or greater. The NO.sub.x storage catalysts can be used to reduce NO.sub.x emissions from diesel or gas combustion engines by contacting the catalysts with the exhaust gas from the engines. The NO.sub.x storage catalysts can be one of the active components of a catalytic converter, which is used to treat exhaust gas from such engines.

  10. Catalyst Initiation in the Oscillatory Carbonylation Reaction

    Directory of Open Access Journals (Sweden)

    Katarina Novakovic

    2011-01-01

    Full Text Available Palladium(II iodide is used as a catalyst in the phenylacetylene oxidative carbonylation reaction that has demonstrated oscillatory behaviour in both pH and heat of reaction. In an attempt to extract the reaction network responsible for the oscillatory nature of this reaction, the system was divided into smaller parts and they were studied. This paper focuses on understanding the reaction network responsible for the initial reactions of palladium(II iodide within this oscillatory reaction. The species researched include methanol, palladium(II iodide, potassium iodide, and carbon monoxide. Several chemical reactions were considered and applied in a modelling study. The study revealed the significant role played by traces of water contained in the standard HPLC grade methanol used.

  11. Isomerization of -carotene by titanium tetrachloride catalyst

    Indian Academy of Sciences (India)

    V Rajendran; B H Chen

    2007-05-01

    Isomerization of all-trans--carotene occurs during shaking with 0.5% of titanium tetrachloride catalyst in methylene chloride at room temperature. In the present study we compared two types of columns C18 and C30 and various solvent systems for the separation of -carotene and its cis isomers by high performance liquid chromatography (HPLC). Results showed that -carotene isomers were resolved by employing a C30 column with a mobile phase of methanol (100%) (A) and methylene chloride (100%) (B) under a gradient elution condition. A total of eleven cis isomers and one all-trans--carotene isomer were resolved within 50 min at a flow rate of 1 ml/min and detection wave-length of 470 nm.

  12. PURIFIED WASTE FCC CATALYST AS A CEMENT REPLACEMENT MATERIAL

    Directory of Open Access Journals (Sweden)

    Danute Vaiciukyniene

    2015-06-01

    Full Text Available Zeolites are commonly used in the fluid catalytic cracking process. Zeolite polluted with oil products and became waste after some time used. The quantity of this waste inevitably rises by expanding rapidly oil industry. The composition of these catalysts depends on the manufacturer and on the process that is going to be used. The main factors retarding hydration process of cement systems and modifying them strength are organic compounds impurities in the waste FCC catalyst. The present paper shows the results of using purified waste FCC catalyst (pFCC from Lithuania oil refinery, as Portland cement replacement material. For this purpose, the purification of waste FCC catalyst (FCC samples was treated with hydrogen peroxide. Hydrogen peroxide (H2O2 is one of the most powerful oxidizers known. By acting of waste with H2O2 it can eliminate the aforementioned waste deficiency, and the obtained product becomes one of the most promising ingredients, in new advanced building materials. Hardened cement paste samples with FCC or pFCC were formed. It was observed that the pFCC blended cements developed higher strength, after 28 days, compared to the samples with FCC or reference samples. Typical content of Portland cement substituting does not exceed 30 % of mass of Portland cement in samples. Reducing the consumption of Portland cement with utilizing waste materials is preferred for reasons of environmental protection.

  13. Ceria-based solid catalysts for organic chemistry.

    Science.gov (United States)

    Vivier, Laurence; Duprez, Daniel

    2010-06-21

    Ceria has been the subject of thorough investigations, mainly because of its use as an active component of catalytic converters for the treatment of exhaust gases. However, ceria-based catalysts have also been developed for different applications in organic chemistry. The redox and acid-base properties of ceria, either alone or in the presence of transition metals, are important parameters that allow to activate complex organic molecules and to selectively orient their transformation. Pure ceria is used in several organic reactions, such as the dehydration of alcohols, the alkylation of aromatic compounds, ketone formation, and aldolization, and in redox reactions. Ceria-supported metal catalysts allow the hydrogenation of many unsaturated compounds. They can also be used for coupling or ring-opening reactions. Cerium atoms can be added as dopants to catalytic system or impregnated onto zeolites and mesoporous catalyst materials to improve their performances. This Review demonstrates that the exceptional surface (and sometimes bulk) properties of ceria make cerium-based catalysts very effective for a broad range of organic reactions.

  14. Metal Phosphate-Supported Pt Catalysts for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Xiaoshuang Qian

    2014-12-01

    Full Text Available Oxides (such as SiO2, TiO2, ZrO2, Al2O3, Fe2O3, CeO2 have often been used to prepare supported Pt catalysts for CO oxidation and other reactions, whereas metal phosphate-supported Pt catalysts for CO oxidation were rarely reported. Metal phosphates are a family of metal salts with high thermal stability and acid-base properties. Hydroxyapatite (Ca10(PO46(OH2, denoted as Ca-P-O here also has rich hydroxyls. Here we report a series of metal phosphate-supported Pt (Pt/M-P-O, M = Mg, Al, Ca, Fe, Co, Zn, La catalysts for CO oxidation. Pt/Ca-P-O shows the highest activity. Relevant characterization was conducted using N2 adsorption-desorption, inductively coupled plasma (ICP atomic emission spectroscopy, X-ray diffraction (XRD, transmission electron microscopy (TEM, CO2 temperature-programmed desorption (CO2-TPD, X-ray photoelectron spectroscopy (XPS, and H2 temperature-programmed reduction (H2-TPR. This work furnishes a new catalyst system for CO oxidation and other possible reactions.

  15. Alternative deNO{sub x} catalysts and technologies

    Energy Technology Data Exchange (ETDEWEB)

    Due-Hansen, J.

    2010-06-15

    Two approaches are undertaken in the present work to reduce the emission of NO{sub x}: by means of catalytic removal, and by NO absorption in ionic liquids. The commercial catalyst used for the selective catalytic reduction (SCR) of nitrogen oxides exhibits high activity and selectivity towards N{sub 2}. However, the vanadia-titania-based catalyst used is very sensitive to deactivation by alkali-species (primarily potassium), which are typically present in high amounts in the flue gas when biomass is combusted. By co-firing with large amounts of CO{sub 2}-neutral straw or wood (to meet stringent CO{sub 2} emission legislation), the lifetime of the traditional SCR catalyst is thus significantly reduced due to the presence of deactivating species originating from the fuel. To develop a catalyst less susceptible to the poisons present in the flue gas, a number of catalysts have been synthesized and tested in the present work, all based on commercially available supports. A highly acidic support consisting of sulfated zirconia was chosen based on preliminary studies. A number of different active species distributed on the support were investigated, such as iron, copper and vanadium oxides. However, based on the catalysts performance in the SCR reaction and their resistances towards potassium, the most promising candidate of the formulations studied was the vanadia-loaded catalyst, i.e. V{sub 2}O{sub 5}-SO{sub 4}2-ZrO{sub 2}. This work, together with an introduction to the catalytic removal of NO{sub x}, are described in chapter 3. The remainder of the first part is concerned with the catalytic NO{sub x} removal (chapter 4) and it addresses the upscaling of the best catalyst candidate. The catalyst was mixed with the natural binding clay (sepiolite) to upscale the selected catalyst to the monolithic level, suitable for installation in gas stream with high flows, e.g. a flue gas duct of a power plant. A series of catalyst pellets with increasing levels of sepiolite were

  16. Robust CoAl Alloy: Highly Active, Reusable and Green Catalyst in the Hydrogenolysis of Glycerol%Robust CoAl Alloy: Highly Active, Reusable and Green Catalyst in the Hydrogenolysis of Glycerol

    Institute of Scientific and Technical Information of China (English)

    郭晓洋; 尹安远; 郭晓东; 郭秀英; 戴维林; 范康年

    2011-01-01

    CoAl alloy catalyst is found, for the first time, to be highly active, selective and reusable for the synthesis of diols via the hydrogenolysis of glycerol under mild conditions. The products and the catalyst could be self-separated from the reaction system through a simple reactor.

  17. Toluene decomposition by DBD-type plasma combined with metal oxide catalysts supported on ferroelectric materials.

    Science.gov (United States)

    Jeong, Jin Guk; Lee, Hyeong Seok; Kang, Youngjin; Lee, Ki Bong; Yoo, Jung Whan

    2013-06-01

    We investigated toluene decomposition with a single-stage plasma catalytic system operated at atmospheric pressure and working at reduced temperature (T < 75 degrees C), where a synergistic catalyst was integrated on ferroelectric BaTiO3 beads with a high dielectric constant. The catalyst species were characterized by FE-SEM and XPS before and after the experiment. The MnO2/BaTiO3 catalyst showed high stability in igniting plasma during destruction of toluene for 230 hours in a lifetime test.

  18. Plasma breaking of thin films into nano-sized catalysts for carbon nanotube synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gao, J.S.; Umeda, K.; Uchino, K.; Nakashima, H.; Muraoka, K

    2003-07-15

    Iron thin films deposited by pulse laser deposition (PLD) were broken into uniform nano-sized catalysts by plasma bombardment for carbon nanotube (CNT) synthesis. Size distributions of broken catalysts were obtained in terms of plasma discharge conditions. Vertically arranged high-density (10{sup 13} per m{sup 2}) CNTs were synthesized using microwave plasma chemical vapor deposition (MP-CVD) system and the gas mixture of N{sub 2} and CH{sub 4} on optimally broken catalysts with few carbonaceous particles on a large area Si substrate. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy (RS) were used to evaluate the obtained CNTs.

  19. 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

    was successfully prepared on a gram scale by using a hydrothermal-based route, purification of biphasic M1-M2 (M2 phase - ICSD 55098) oxide systems, and an innovative approach utilizing a superheated water vapor treatment of calcined precursors. The influence of the preparation technique on the particle morphology...... 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....

  20. New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

    Directory of Open Access Journals (Sweden)

    Agnieszka Hryniewicka

    2015-12-01

    Full Text Available The synthesis of a new type of Hoveyda–Grubbs 2nd generation catalyst bearing a modified N-heterocyclic carbene ligands is reported. The new catalyst contains an NHC ligand symmetrically substituted with chromanyl moieties. The complex was tested in model CM and RCM reactions. It showed very high activity in CM reactions with electron-deficient α,β-unsaturated compounds even at 0 °C. It was also examined in more demanding systems such as conjugated dienes and polyenes. The catalyst is stable, storable and easy to purify.

  1. Ethoxylation of p-chloronitrobenzene using phase-transfer catalysts by ultrasound irradiation: a kinetic study.

    Science.gov (United States)

    Wang, Maw-Ling; Rajendran, Venugopal

    2007-03-01

    Ethoxy-4-nitrobenzene was synthesized by the reaction of 4-chloronitrobenzene with potassium ethoxide in a homogeneous system using benzyltriethylammonium chloride (QCl) as a phase-transfer catalyst at 50 degrees C under ultrasound irradiation conditions. The use of phase-transfer catalysts and ultrasound has been compared and demonstrated in this nucleophilic substitution reactions. The kinetics of the reaction depends on the effect of amount of catalyst, quaternary ammonium salts, agitation speed, amount of potassium hydroxide, amount of ethanol, temperature and the frequency of the ultrasound waves on the conversion of the reaction.

  2. Acetic Acid Formation by Selective Aerobic Oxidation of Aqueous Ethanol over Heterogeneous Ruthenium Catalysts

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Hanning, Christopher William

    2012-01-01

    Heterogeneous catalyst systems comprising ruthenium hydroxide supported on different carrier materials, titania, alumina, ceria, and spinel (MgAl2O4), were applied in selective aerobic oxidation ethanol to form acetic acid, an important bulk chemical and food ingredient. The catalysts were...... of catalysts, oxidant pressure, reaction temperature, and substrate concentration were investigated. Quantitative yield of acetic acid was obtained with 1.2 wt % Ru(OH)x/CeO2 under optimized conditions (150 °C, 10 bar O2, 12 h of reaction time, 0.23 mol % Ru to substrate)....

  3. XAFS characterization of industrial catalysts: in situ study of phase transformation of nickel sulfide

    Science.gov (United States)

    Wang, J.; Jia, Z.; Wang, Q.; Zhao, S.; Xu, Z.; Yang, W.; Frenkel, A. I.

    2016-05-01

    The online sulfiding process for nickel-contained catalyst often ends up with a nickel sulfide mixture in refinery plant. To elucidate the local environment of nickel and its corresponding sulfur species, a model catalyst (nickel sulfide) and model thermal process were employed to explore the possibilities for characterization of real catalysts in industrial conditions. The present investigation shows effectiveness of in situ XANES and EXAFS measurements for studying the phase stability and phase composition in these systems, which could be used to simulate real sulfiding process in industrial reactions, such as hydrodesulfurizations of oil.

  4. On the Use of Fourier Transform Infrared (FT-IR) Spectroscopy and Synthetic Calibration Spectra to Quantify Gas Concentrations in a Fischer-Tropsch Catalyst System

    Science.gov (United States)

    Ferguson, Frank T.; Johnson, Natasha M.; Nuth, Joseph A., III

    2015-01-01

    One possible origin of prebiotic organic material is that these compounds were formed via Fischer-Tropsch-type (FTT) reactions of carbon monoxide and hydrogen on silicate and oxide grains in the warm, inner-solar nebula. To investigate this possibility, an experimental system has been built in which the catalytic efficiency of different grain-analog materials can be tested. During such runs, the gas phase above these grain analogs is sampled using Fourier transform infrared (FT-IR) spectroscopy. To provide quantitative estimates of the concentration of these gases, a technique in which high-resolution spectra of the gases are calculated using the high-resolution transmission molecular absorption (HITRAN) database is used. Next, these spectra are processed via a method that mimics the processes giving rise to the instrumental line shape of the FT-IR spectrometer, including apodization, self-apodization, and broadening due to the finite resolution. The result is a very close match between the measured and computed spectra. This technique was tested using four major gases found in the FTT reactions: carbon monoxide, methane, carbon dioxide, and water. For the ranges typical of the FTT reactions, the carbon monoxide results were found to be accurate to within 5% and the remaining gases accurate to within 10%. These spectra can then be used to generate synthetic calibration data, allowing the rapid computation of the gas concentrations in the FTT experiments.

  5. High-Performance Monopropellants and Catalysts Evaluated

    Science.gov (United States)

    Reed, Brian D.

    2004-01-01

    The NASA Glenn Research Center is sponsoring efforts to develop advanced monopropellant technology. The focus has been on monopropellant formulations composed of an aqueous solution of hydroxylammonium nitrate (HAN) and a fuel component. HAN-based monopropellants do not have a toxic vapor and do not need the extraordinary procedures for storage, handling, and disposal required of hydrazine (N2H4). Generically, HAN-based monopropellants are denser and have lower freezing points than N2H4. The performance of HAN-based monopropellants depends on the selection of fuel, the HAN-to-fuel ratio, and the amount of water in the formulation. HAN-based monopropellants are not seen as a replacement for N2H4 per se, but rather as a propulsion option in their own right. For example, HAN-based monopropellants would prove beneficial to the orbit insertion of small, power-limited satellites because of this propellant's high performance (reduced system mass), high density (reduced system volume), and low freezing point (elimination of tank and line heaters). Under a Glenn-contracted effort, Aerojet Redmond Rocket Center conducted testing to provide the foundation for the development of monopropellant thrusters with an I(sub sp) goal of 250 sec. A modular, workhorse reactor (representative of a 1-lbf thruster) was used to evaluate HAN formulations with catalyst materials. Stoichiometric, oxygen-rich, and fuelrich formulations of HAN-methanol and HAN-tris(aminoethyl)amine trinitrate were tested to investigate the effects of stoichiometry on combustion behavior. Aerojet found that fuelrich formulations degrade the catalyst and reactor faster than oxygen-rich and stoichiometric formulations do. A HAN-methanol formulation with a theoretical Isp of 269 sec (designated HAN269MEO) was selected as the baseline. With a combustion efficiency of at least 93 percent demonstrated for HAN-based monopropellants, HAN269MEO will meet the I(sub sp) 250 sec goal.

  6. Cr(VI) and azo dye removal using a hollow-fibre membrane system functionalized with a biogenic Pd-magnetite catalyst.

    Science.gov (United States)

    Coker, V S; Garrity, A; Wennekes, W B; Roesink, H D W; Cutting, R S; Lloyd, J R

    2014-01-01

    This study investigates the application of a hybrid system combining hollow-fibre membrane technology with the reductive abilities of magnetic nanoparticles for the remediation of toxic Cr(VI) and the azo dye, Remazol Black B. Nano-scale biogenic magnetite (Fe3O4), formed by microbial reduction of the mineral ferrihydrite, has a high reductive capacity due to the presence of Fe(II) in the mineral structure. The magnetic nanoparticles (approximately 20 nm) can be arrayed with Pd0 nanoparticles (approximately 5 nm) making a catalytically active nanomaterial. Membrane units, with and without nanoparticles, were challenged with either Cr(VI) or azo dye and some were supplemented with sodium formate, as an electron donor for contaminant reduction promoted by the Pd. The combination of Pd-magnetite with formate resulted in the most effective remediation strategy for both contaminants and the lifetime of the membrane unit was also increased, with 55% (19 days) and 70% (23 days) removal of the azo dye and Cr(VI), respectively. Low flow rates of 0.1 ml/min resulted in improved efficiencies due to increased contact time with the membrane/nanoparticle unit, with 70-75% removal of each contaminant. Chemical analyses of the nanoparticles post-exposure to Cr(VI) in the membrane modules indicated Pd to be more oxidized when Cr removal was maximized, and that the Cr was partially reduced to Cr(III) at the surface of the magnetite. These results have demonstrated that hollow-fibre membrane units can be enhanced for the removal of soluble, redox sensitive contaminants by incorporation of a layer of palladized biogenic nanoparticulate magnetite.

  7. Friedel-Crafts Alkylation of o-xylene over V2O5/ZrO2 Catalysts

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2012-01-01

    Full Text Available The present study has undertaken the Friedel-Crafts benzylation of aromatics over the V2O5/ZrO2 catalysts systems. Catalysts with different V2O5 content (0-15wt %) was prepared by wet impregnation method and characterized by XRD, BET surface area...

  8. Catalysts for cleaner combustion of coal, wood and briquettes sulfur dioxide reduction options for low emission sources

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.V. [Global Environmental Solutions, Inc., Morton Grove, IL (United States)

    1995-12-31

    Coal fired, low emission sources are a major factor in the air quality problems facing eastern European cities. These sources include: stoker-fired boilers which feed district heating systems and also meet local industrial steam demand, hand-fired boilers which provide heat for one building or a small group of buildings, and masonary tile stoves which heat individual rooms. Global Environmental Systems is marketing through Global Environmental Systems of Polane, Inc. catalysts to improve the combustion of coal, wood or fuel oils in these combustion systems. PCCL-II Combustion Catalysts promotes more complete combustion, reduces or eliminates slag formations, soot, corrosion and some air pollution emissions and is especially effective on high sulfur-high vanadium residual oils. Glo-Klen is a semi-dry powder continuous acting catalyst that is injected directly into the furnace of boilers by operating personnel. It is a multi-purpose catalyst that is a furnace combustion catalyst that saves fuel by increasing combustion efficiency, a cleaner of heat transfer surfaces that saves additional fuel by increasing the absorption of heat, a corrosion-inhibiting catalyst that reduces costly corrosion damage and an air pollution reducing catalyst that reduces air pollution type stack emissions. The reduction of sulfur dioxides from coal or oil-fired boilers of the hand fired stoker design and larger, can be controlled by the induction of the Glo-Klen combustion catalyst and either hydrated lime or pulverized limestone.

  9. [Hmim]3PW12O40: A high-efficient and green catalyst for the acetalization of carbonyl compounds

    Institute of Scientific and Technical Information of China (English)

    Yan; Lü

    2010-01-01

    [Hmim]3PW12O40 was developed and used in the acetalization of carbonyl compounds in excellent yields. The ionic liquid-heteropoly acid hybrid compound and reaction medium formed temperature-dependent phase-separation system with the ease of product as well as catalyst separation. The catalyst was recycled more than 10 times without any apparent loss of catalytic activity.

  10. OXIDATION OF MERCURY ACROSS SCR CATALYSTS IN COAL-FIRED POWER PLANTS BURNING LOW RANK FUELS

    Energy Technology Data Exchange (ETDEWEB)

    Constance Senior; Temi Linjewile

    2003-10-31

    This is the third Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-03NT41728. The objective of this program is to measure the oxidation of mercury in flue gas across SCR catalyst in a coal-fired power plant burning low rank fuels using a slipstream reactor containing multiple commercial catalysts in parallel. The Electric Power Research Institute (EPRI) and Argillon GmbH are providing co-funding for this program. This program contains multiple tasks and good progress is being made on all fronts. During this quarter, the second set of mercury measurements was made after the catalysts had been exposed to flue gas for about 2,000 hours. There was good agreement between the Ontario Hydro measurements and the SCEM measurements. Carbon trap measurements of total mercury agreed fairly well with the SCEM. There did appear to be some loss of mercury in the sampling system toward the end of the sampling campaign. NO{sub x} reductions across the catalysts ranged from 60% to 88%. Loss of total mercury across the commercial catalysts was not observed, as it had been in the March/April test series. It is not clear whether this was due to aging of the catalyst or to changes in the sampling system made between March/April and August. In the presence of ammonia, the blank monolith showed no oxidation. Two of the commercial catalysts showed mercury oxidation that was comparable to that in the March/April series. The other three commercial catalysts showed a decrease in mercury oxidation relative to the March/April series. Oxidation of mercury increased without ammonia present. Transient experiments showed that when ammonia was turned on, mercury appeared to desorb from the catalyst, suggesting displacement of adsorbed mercury by the ammonia.

  11. New Trends in Gold Catalysts

    Directory of Open Access Journals (Sweden)

    Leonarda F. Liotta

    2014-07-01

    Full Text Available Gold is an element that has fascinated mankind for millennia. The catalytic properties of gold have been a source of debate, due to its complete chemical inertness when in a bulk form, while it can oxidize CO at temperatures as low as ~200 K when in a nanocrystalline state, as discovered by Haruta in the late 1980s [1]. Since then, extensive activity in both applied and fundamental research on gold has been initiated. The importance of the catalysis by gold represents one of the fasted growing fields in science and is proven by the promising applications in several fields, such as green chemistry and environmental catalysis, in the synthesis of single-walled carbon nanotubes, as modifiers of Ni catalysts for methane steam and dry reforming reactions and in biological and electrochemistry applications. The range of reactions catalyzed by gold, as well as the suitability of different supports and the influence of the preparation conditions have been widely explored and optimized in applied research [2]. Gold catalysts appeared to be very different from the other noble metal-based catalysts, due to their marked dependence on the preparation method, which is crucial for the genesis of the catalytic activity. Several methods, including deposition-precipitation, chemical vapor deposition and cation adsorption, have been applied for the preparation of gold catalysts over reducible oxides, like TiO2. Among these methods, deposition-precipitation has been the most frequently employed method for Au loading, and it involves the use of tetrachloroauric (III acid as a precursor. On the other hand, the number of articles dealing with Au-loaded acidic supports is smaller than that on basic supports, possibly because the deposition of [AuCl4]− or [AuOHxCl4−x]− species on acidic supports is difficult, due to their very low point of zero charge. Despite this challenge, several groups have reported the use of acidic zeolites as supports for gold. Zeolites

  12. Off-gas catalyst. Abgaskatalysator

    Energy Technology Data Exchange (ETDEWEB)

    Saris, L.; Kloeck, H.

    1987-02-19

    The invention deals with a waste gas catalyst with a thermo-resistant SiO{sub 2} and Al{sub 2}O{sub 3} containing carrier of snarled ceramic fibres which form between themselves the flow paths for the waste gas to be purified and which are coated with platinum, palladium and/or rhodium. The ceramic fibres forming the carrier consist of SiO{sub 2} and Al{sub 2}O{sub 3} and have a diameter of 1 to 10 {mu}m. (orig./RB).

  13. Thermodynamic Properties of Supported Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gorte, Raymond J.

    2014-03-26

    The goals of this work were to develop Coulometric Titration as a method for characterizing the thermodynamic redox properties of oxides and to apply this technique to the characterization of ceria- and vanadia-based catalysts. The redox properties of ceria and vanadia are a major part of what makes these materials catalytically active but their properties are also dependent on their structure and the presence of other oxides. Quantifying these properties through the measurement of oxidation energetics was the goal of this work.

  14. The application of water-soluble ruthenium catalysts for the hydrogenation of the dichloromethane soluble fraction of fast pyrolysis oil and related model compounds in a two phase aqueous-organic system

    NARCIS (Netherlands)

    Mahfud, F.H.; Bussemaker, S.; Kooi, B.J.; ten Brink, Gert; Heeres, H.J.

    2007-01-01

    The hydrogenation of a dichloromethane soluble fraction of flash pyrolysis oil (bio-oil, BO), obtained by treatment of BO with a water–dichloromethane solvent mixture, was investigated using a water-soluble homogeneous ruthenium catalyst (RuCl3·3H2O/tris(m-sulfonatophenyl)phosphine, TPPTS). The

  15. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    Energy Technology Data Exchange (ETDEWEB)

    Amitava Sarkar; James K. Neathery; Burtron H. Davis

    2006-12-31

    A fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of operation since the reaction is highly exothermic. Consequently, heavy wax products in one approach may be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase iron-based FTS and is a key factor for optimizing operating costs. The separation problem is further compounded by attrition of iron catalyst particles and the formation of ultra-fine particles.

  16. Methane decomposition on Ni-Cu alloyed Raney-type catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, A.F.; Orfao, J.J.M.; Figueiredo, J.L. [Laboratorio de Catalise e Materiais, Laboratorio Associado LSRE/LCM, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)

    2009-06-15

    In the present work, we report on the performance of Ni-Cu alloyed Raney-type catalysts for the production of hydrogen by catalytic methane decomposition. The activity of the catalysts was assessed by comparing the experimental conversions with the calculated equilibrium conversions for each set of experimental conditions. The stability of the catalysts was assessed by comparing the maximum conversions with the conversions at the end of 5 h tests. Comparison with monometallic Ni Raney-type catalytic systems shows that Cu addition significantly improves catalyst stability. Excellent results were obtained when the Ni-Cu Raney-type system was thermally treated in situ at 600 C, as a result of incipient alloy formation. (author)

  17. Reduce NOx Emissions by Adsorber-Reduction Catalyst on Lean Burn Gasoline Engine

    Directory of Open Access Journals (Sweden)

    Dongpeng Yue

    2013-09-01

    Full Text Available The effect of a new catalyst system composed of traditional three way catalyst converter and adsorber-reduction catalysis converter on the emission characteristics and BSFC (Breake Specific Fuel Consumption- BSFCof a lean burn gasoline engine operated were investigated in this paper under different schemes of catalyst converter arrangement and different speeds and loads. The results show that the position of Three Way Catalyst is before the NOx adsorber Catalyst was the best scheme of catalyst converter arrangement. Which has the highest converter efficiency of reduction NOx emission in lean burn gasoline engine. The effects of speed on the exhaust emission and BSFC were also related to the ratio of lean burn time to rich burn time and the absolute value of both time of the adsorber-reduction catalyst converter. The load of the engine was the main influential factor to the exhaust emission characteristics and BSFC of lean burn gasoline engine, and the more load of the engine was, the more NOx emission , the less NOx conversion rate (CNOx and the better BSFC were.

  18. Performance of Ni/Nano-ZrO2 Catalysts for CO Preferential Methanation

    Institute of Scientific and Technical Information of China (English)

    刘其海; 董新法; 刘自力

    2014-01-01

    Large surface areas nano-scale zirconia was prepared by the self-assembly route and was employed as support in nickel catalysts for the CO selective methanation. The effects of Ni loading and the catalyst calcination temperature on the performance of the catalyst for CO selective methanation reaction were investigated. The cata-lysts were characterized by Brunauer-Emmett-Teller (BET), transmission electron microscope (TEM), X-ray dif-fraction (XRD) and temperature-programmed reduction (TPR). The results showed that the as-synthesized Ni/nano-ZrO2 catalysts presented high activity for CO methanation due to the interaction between Ni active particle and nano zir-conia support. The selectivity for the CO methanation influenced significantly by the particle size of the active Ni species. The exorbitant calcination resulted in the conglomeration of dispersive Ni particles and led to the decrease of CO methanation selectivity. Among the catalysts studied, the 7.5%(by mass) Ni/ZrO2 catalyst calcinated at 500 °C was the most effective for the CO selective methanation. It can preferentially catalyze the CO methanation with a higher 99%conversion in the CO/CO2 competitive methanation system over the temperature range of 260-280 °C, while keeping the CO2 conversion relatively low.

  19. Amphiphilic phase-transforming catalysts for transesterification of triglycerides

    Science.gov (United States)

    Nawaratna, Gayan Ivantha

    Heterogeneous catalytic reactions that involve immiscible liquid-phase reactants are challenging to conduct due to limitations associated with mass transport. Nevertheless, there are numerous reactions such as esterification, transesterification, etherification, and hydrolysis where two immiscible liquid reactants (such as polar and non-polar liquids) need to be brought into contact with a catalyst. With the intention of alleviating mass transport issues associated with such systems but affording the ability to separate the catalyst once the reaction is complete, the overall goal of this study is geared toward developing a catalyst that has emulsification properties as well as the ability to phase-transfer (from liquid-phase to solid-phase) while the reaction is ongoing and evaluating the effectiveness of such a catalytic process in a practical reaction. To elucidate this concept, the transesterification reaction was selected. Metal-alkoxides that possess acidic and basic properties (to catalyze the reaction), amphiphilic properties (to stabilize the alcohol/oil emulsion) and that can undergo condensation polymerization when heated (to separate as a solid subsequent to the completion of the reaction) were used to test the concept. Studies included elucidating the effect of metal sites and alkoxide sites and their concentration effects on transesterification reaction, effect of various metal alkoxide groups on the phase stability of the reactant system, and kinetic effects of the reaction system. The studies revealed that several transition-metal alkoxides, especially, titanium and yttrium based, responded positively to this reaction system. These alkoxides were able to be added to the reaction medium in liquid phase and were able to stabilize the alcohol/oil system. The alkoxides were selective to the transesterification reaction giving a range of ester yields (depending on the catalyst used). It was also observed that transition-metal alkoxides were able to be

  20. European workshop on spent catalysts. Book of abstracts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    In 1999 and 2002 two well attended workshops on recycling, regeneration, reuse and disposal of spent catalysts took place in Frankfurt. This series has been continued in Berlin. The workshop was organized in collaboration with DGMK, the German Society for Petroleum and Coal Science and Technology. Contributions were in the following areas of catalyst deactivation: recycling of spent catalysts in chemical and petrochemical industry, recycling of precious metal catalysts and heterogenous base metal catalysts, legal aspects of transboundary movements, catalyst regeneration, quality control, slurry catalysts, commercial reactivation of hydrotreating catalysts. (uke)