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Auswahl der wissenschaftlichen Literatur zum Thema „Catalyse de fer“
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Zeitschriftenartikel zum Thema "Catalyse de fer"
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Siffert, B., und A. Naidja. „Decarboxylation catalytique de l'acide oxaloacetique en presence de montmorillonite“. Clay Minerals 22, Nr. 4 (Dezember 1987): 435–46. http://dx.doi.org/10.1180/claymin.1987.022.4.07.
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ResumeLa décarboxylation de l'acide oxaloacétique en acide pyruvique a été étudiée en présence de montmorillonite saturée en cations différents et des mêmes cations à l'état libre (non incorporés). L'action catalytique dépend de la nature du cation, cést-à-dire de sa facilité à former des complexes avec l'acide oxaloacétique. Le réseau argileux intervient dans la catalyse essentiellement par les atomes d'aluminium (ou de fer) situés sur les bords des feuillets argileux. Il joue le rôle d'un métalloenzyme biologique. Le calcul des énergies d'activation pour les différents systèmes met bien en évidence l'activité catalytique de l'argile. En présence du phyllosilicate, la réaction a lieu avec un bon rendement jusqu'à une température de 60°C.
2
D'Hont, M., und J. C. Jungers. „Contribution à l'étude du mécanisme de la catalyse hétérogène: L'Activation de l'Azote par le fer et le Nickel“. Bulletin des Sociétés Chimiques Belges 58, Nr. 10-12 (01.09.2010): 450–59. http://dx.doi.org/10.1002/bscb.19490581004.
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3
Jurkowski, Artur, und Zofia Lendzion-Bieluń. „Determination of Fe2+/Fe3+ mole ratio based on the change of precursor lattice parameters of wustite based iron catalysts for the ammonia synthesis“. Polish Journal of Chemical Technology 21, Nr. 3 (01.09.2019): 48–52. http://dx.doi.org/10.2478/pjct-2019-0029.
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Abstract In the presented article, oxide forms of iron catalysts with the wustite structure and with a R = Fe2+/Fe3+ molar ratio in the range from 3.78 to 8.16 were investigated. The chemical composition of the tested catalyst precursors was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The X-ray diffraction (XRD) technique was used to determine the phase composition and location of reflections characteristic of the Fe1−xO phase. The molar ratio of iron ions R = Fe2+/Fe3+ was determined by manganometric titration. The distribution of promoters in the structure of iron catalyst precursors with different R = Fe2+/Fe3+ ratio was determined by a selective etching method. The dependence of the lattice parameter ao value in the crystal structure Fe1−xO on the molar ratio R = Fe2+/Fe3+ was determined. On the basis of the determined dependence, R can easily be calculated in catalyst precursors of the wustite structure.
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Sun, Xinhui, Antonios Arvanitis, Devaiah Damma, Noe T. Alvarez, Vesselin Shanov, Panagiotis G. Smirniotis und Junhang Dong. „Carbon Nanotube Formation on Cr-Doped Ferrite Catalyst during Water Gas Shift Membrane Reaction: Mechanistic Implications and Extended Studies on Dry Gas Conversions“. Catalysts 10, Nr. 8 (12.08.2020): 927. http://dx.doi.org/10.3390/catal10080927.
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A nanocrystalline chromium-doped ferrite (FeCr) catalyst was shown to coproduce H2 and multiwalled carbon nanotubes (MWCNTs) during water gas shift (WGS) reaction in a H2-permselective zeolite membrane reactor (MR) at reaction pressures of ~20 bar. The FeCr catalyst was further demonstrated in the synthesis of highly crystalline and dimensionally uniform MWCNTs from a dry gas mixture of CO and CH4, which were the apparent sources for MWCNT growth in the WGS MR. In both the WGS MR and dry gas reactions, the operating temperature was 500 °C, which is significantly lower than those commonly used in MWCNT production by chemical vapor deposition (CVD) method from CO, CH4, or any other precursor gases. Extensive ex situ characterizations of the reaction products revealed that the FeCr catalyst remained in partially reduced states of Fe3+/Fe2+ and Cr6+/Cr3+ in WGS membrane reaction while further reduction of Fe2+ to Fe0 occurred in the CO/CH4 dry gas environments. The formation of the metallic Fe nanoparticles or catalyst surface dramatically improved the crystallinity and dimensional uniformity of the MWCNTs from dry gas reaction as compared to that from WGS reaction in the MR. Reaction of the CO/CH4 mixture containing 500 ppmv H2S also resulted in high-quality MWCNTs similar to those from the H2S-free feed gas, demonstrating excellent sulfur tolerance of the FeCr catalyst that is practically meaningful for utilization of biogas and cheap coal-derived syngas.
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Gholami, Fatemeh, Zahra Gholami, Martin Tomas, Veronika Vavrunkova, Somayeh Mirzaei und Mohammadtaghi Vakili. „Promotional Effect of Manganese on Selective Catalytic Reduction of NO by CO in the Presence of Excess O2 over M@La–Fe/AC (M = Mn, Ce) Catalyst“. Catalysts 10, Nr. 11 (13.11.2020): 1322. http://dx.doi.org/10.3390/catal10111322.
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The catalytic performance of a series of La-Fe/AC catalysts was studied for the selective catalytic reduction (SCR) of NO by CO. With the increase in La content, the Fe2+/Fe3+ ratio and amount of surface oxygen vacancies (SOV) in the catalysts increased; thus the catalytic activity improved. Incorporating the promoters to La3-Fe1/active carbon (AC) catalyst could affect the catalyst activity by changing the electronic structure. The increase in Fe2+/Fe3+ ratio after the promoter addition is possibly due to the extra synergistic interaction of M (Mn and Ce) and Fe through the redox equilibrium of M3+ + Fe3+ ↔ M4+ + Fe2+. This phenomenon could have improved the redox cycle, enhanced the SOV formation, facilitated NO decomposition, and accelerated the CO-SCR process. The presence of O2 enhanced the formation of the C(O) complex and improved the activation of the metal site. Mn@La3-Fe1/AC catalyst revealed an excellent NO conversion of 93.8% at 400 °C in the presence of 10% oxygen. The high catalytic performance of MnOx and double exchange behavior of Mn3+ and Mn4+ can increase the number of SOV and improve the catalytic redox properties.
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Wang, Yizhou, Zheng Wang, Qiuyue Zhang, Yanping Ma, Gregory A. Solan, Yang Sun und Wen-Hua Sun. „Non-Symmetrically Fused Bis(arylimino)pyridines with para-Phenyl Substitution: Exploring Their Use as N′,N,N″-Supports in Iron Ethylene Polymerization Catalysis“. Catalysts 14, Nr. 3 (21.03.2024): 213. http://dx.doi.org/10.3390/catal14030213.
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Through the implementation of a one-pot strategy, five examples of non-symmetrical [N,N-diaryl-11-phenyl-1,2,3,7,8,9,10-heptahydrocyclohepta[b]quinoline-4,6-diimine]iron(II) chloride complexes (aryl = 2,6-Me2Ph Fe1, 2,6-Et2Ph Fe2, 2,6-i-Pr2Ph Fe3, 2,4,6-Me3Ph Fe4, and 2,6-Et2-4-MePh Fe5), incorporating fused six- and seven-membered carbocyclic rings and appended with a remote para-phenyl group, were readily prepared. The molecular structures of Fe2 and Fe3 emphasize the variation in fused ring size and the skewed disposition of the para-phenyl group present in the N′,N,N″-ligand support. Upon activation with MAO or MMAO, Fe1–Fe5 all showed high catalytic activity for ethylene polymerization, with an exceptional level of 35.92 × 106 g (PE) mol−1 (Fe) h−1 seen for mesityl-substituted Fe4/MMAO operating at 60 °C. All catalysts generated highly linear polyethylene with good control of the polymer molecular weight achievable via straightforward manipulation of run temperature. Typically, low molecular weight polymers with narrow dispersity (Mw/Mn = 1.5) were produced at 80 °C (MMAO: 3.7 kg mol−1 and MAO: 4.9 kg mol−1), while at temperatures between 40 °C and 50 °C, moderate molecular weight polymers were obtained (MMAO: 35.6–51.6 kg mol−1 and MAO: 72.4–95.5 kg mol−1). Moreover, analysis of these polyethylenes by 1H and 13C NMR spectroscopy highlighted the role played by both β-H elimination and chain transfer to aluminum during chain termination, with the highest rate of β-H elimination seen at 60 °C for the MMAO-activated system and 70 °C for the MAO system.
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Lin, Y. T., und M. C. Lu. „Catalytic action of goethite in the oxidation of 2-chlorophenols with hydrogen peroxide“. Water Science and Technology 55, Nr. 12 (01.06.2007): 101–6. http://dx.doi.org/10.2166/wst.2007.386.
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The use of goethite and hydrogen peroxide was recently found to effectively oxidise organic compounds. This research was to investigate the effect of adsorption, pH, Fe2 + and Fe3 + on 2-CP oxidation. Results indicated that 2-CP can be decomposed with hydrogen peroxide catalysed by goethite and the oxidation rate increased with decreasing goethite particle size. The optimum oxidation rate was observed at the pH below 3.0.Addition of Fe2 + and Fe3 + can enhance the catalytic oxidation rate of 2-CP very efficiently. The main mechanism of goethite catalysing hydrogen peroxide to oxidise 2-CP may be due to the catalysis of ferrous ions and goethite surface.
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Gowri Krishnan, Shamala, Fei Ling Pua, Kumaran Palanisamy und Sharifah Nabihah. „Preparation of Oil Palm EFB Derived Solid Acid Catalyst for Esterification Reaction: Effect of Calcination Temperature“. Key Engineering Materials 701 (Juli 2016): 117–21. http://dx.doi.org/10.4028/www.scientific.net/kem.701.117.
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Oil palm empty fruit bunch (EFB) is one of the palm biomass produced in abundance after oil extraction in Malaysia. This study was focused to utilize this waste biomass as a beneficial raw materials. EFB was used to prepare new solid acid catalyst for biodiesel production. EFB was converted into solid catalyst via direct impregnation method and it was used to catalyse esterification of oleic acid. Transition metal sulfide salt, Fe2(SO4)3 was impregnated on EFB fibres. Effect of different calcination temperature was studied on the properties of catalyst. The result shows that Fe2(SO4)3 based solid acid catalyst which calcined at 500°C exhibited the highest catalytic activity with 93.90% esterification rate was achieved. The morphology and surface chemistry and function group determination for the solid acid catalyst were characterized by SEM-EDX and FTIR.
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Boscá, Lisardo, und Antonio Castrillo. „Nitric oxide, vascular function and exercise“. Biochemist 34, Nr. 3 (01.06.2012): 28–32. http://dx.doi.org/10.1042/bio03403028.
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NO (nitric oxide) is a diffusible gas molecule produced intracellularly by three distinct nitric oxide synthase (NOS) enzymes that are highly conserved in mammalian species. The NOS enzymes are haemcontaining proteins that catalyse a fiveelectron oxidation process of the guanidino nitrogen of arginine and in the presence of O2. NOS activity is, in fact, a tandem of two consecutive reactions: a reductase step catalysed by a moiety of NOS homologous with the cytochrome P450 reductase, including the NADPH and flavin nucleotide cofactorbinding domains, and an oxygenase step coupling the reduction of Fe3+ to Fe2+ in the haem to the release of NO and citrulline from arginine and molecular oxygen. The reaction requires several cofactors, including tetrahydrobiopterin and calcium/calmodulin.
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Hu, Sihai, Yaoguo Wu, Hairui Yao, Cong Lu und Chengjun Zhang. „Enhanced Fenton-like removal of nitrobenzene via internal microelectrolysis in nano zerovalent iron/activated carbon composite“. Water Science and Technology 73, Nr. 1 (15.09.2015): 153–60. http://dx.doi.org/10.2166/wst.2015.467.
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The efficiency of Fenton-like catalysis using nano zerovalent iron (nZVI) is limited by nZVI aggregation and activity loss due to inactive ferric oxide forming on the nZVI surface, which hinders electron transfer. A novel iron–carbon composite catalyst consisting of nZVI and granular activated carbon (GAC), which can undergo internal iron–carbon microelectrolysis spontaneously, was successfully fabricated by the adsorption–reduction method. The catalyst efficiency was evaluated in nitrobenzene (NB) removal via the Fenton-like process (H2O2-nZVI/GAC). The results showed that nZVI/GAC composite was good for dispersing nZVI on the surface of GAC, which permitted much better removal efficiency (93.0%) than nZVI (31.0%) or GAC (20.0%) alone. Moreover, iron leaching decreased from 1.28 to 0.58 mg/L after reaction of 240 min and the oxidation kinetic of the Fenton-like reaction can be described well by the second-order reaction kinetic model (R2 = 0.988). The composite catalyst showed sustainable catalytic ability and GAC performed as a medium for electron transfer in internal iron–carbon microelectrolysis to promote Fe2+ regeneration and Fe3+/Fe2+ cycles. Therefore, this study represents an important method to design a low cost and high efficiency Fenton-like catalyst in practical application.
Dissertationen zum Thema "Catalyse de fer"
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Rangheard, Claudine. „Oligomérisation de l'éthylène par les complexes du fer“. Lyon 1, 2008. http://www.theses.fr/2008LYO10332.
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Vers la fin des années 90, les systèmes à base de fer associés à des ligands azotés de type diimines ou bis(imino)pyridines ont été décrits comme précurseurs de catalyseurs pour la polymérisation et /ou l'oligomérisation des oléfines. Ces catalyseurs présentent de nombreux avantages de par leur coût, leur facilité de préparation et de manipulation et leur impact environnemental négligeable. De plus, ils offrent la possibilité de pouvoir contrôler leur activité et leur sélectivité pour l'oligomérisation grâce à la modularité de l'architecture de leur ligand. Nous reportons ici l'étude de la réactivité des complexes bis(imino)pyridines du Fe11, activés par un aluminoxane, en oligomérisation/polymérisation de l'éthylène ainsi que la conception, la synthèse et la caractérisation de nouveaux ligands et complexes à base de fer et l'étude de leur réactivité vis-à-vis de l'éthylène. Nous exposons ainsi la synthèse de nouveaux complexes de fer associés à des ligands azotés potentiellement tridentes originaux basés sur la structure 2,4-dipyridin-2-yl-2-méthyl-1,2-dihydro-1,10-phénantroline. Nous montrons que ces précurseurs de catalyseurs, une fois oxydés et activés par le MAO, présentent des propriétés catalytiques et des sélectivités intéressantes pour l'oligomérisation de l'éthylèneAt the end of the 90’s, iron catalysts based on nitrogen-containing ligands, such as diimines and bis(imino)pyridines have been described as catalysts precursors for olefins oligomerization/polymerization. Theses catalysts display a wide range of advantages, spanning from the ease of preparation and handling to the use of low-cost metals with negligible environmental impact. Another interesting feature of theses complexes is provided by the facile tuning of their oligomerization activity by simple modifications of the ligand architecture. In this study, we report bis(imino)pyridine Fe11 complexes reactivities, after activation by an aluminoxane, for the ethylene oligomerization/polymerization, as well as the design, synthesis and characterization of new ligands and the reactivity of their iron complexes toward ethylene. We report the synthesis of new iron complexes associated with new potentially tridentate nitrogen ligands based on 2,4-dipyridin-2-yl-2-methyl-1,2-dihydro-1,10-phenantroline scaffold. We show that these catalysts precursors, once oxidized and activated by MAO, are active and display interesting selectivity for ethylene oligomerization
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Wei, Duo. „Iron, manganese and rhenium-catalyzed (de)hydrogenation and hydroelementation reactions“. Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1S105.
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L’objectif de ce travail doctoral a été de développer de nouvelles méthodes éco-compatibles pour réaliser efficacement des réactions de (dé)hydrogénation et d’hydroélémentation catalysées par des catalyseurs bien définis de fer, de manganèse et également de rhénium. La première partie de ce travail porte sur le développement des premiers exemples de réaction de borylation de dérivés styrènes et acétyléniques terminaux avec le pinacolborane via une réaction d’activation de liaison C-H catalysée par des systèmes à base de Fe(PMe3)4 ou de Fe(OTf)2/ DABCO. Dans une seconde partie, des complexes de fer à base de ligands carbènes N-hétérocycliques (NHC) tels que Fe(CO)4(IMes) et [CpFe(CO)2(IMes)][I] ont été efficacement utilisés pour la synthèse d’une grande variété d’amines cycliques (pyrrolidines, pipéridines et azépanes) via une réaction d’amination réductrice catalytique en présence d’hydrosilanes. De façon très intéressante, les catalyseurs commerciaux Mn2(CO)10 et Re2(CO)10 en présence de triéthylsilane, ont permis de réduire sélectivement les esters, acides carboxyliques et amides en acétals, alcools et amines correspondants. En complément de l’hydrosilylation, l’hydrogénation d’aldéhydes, cétones et aldimines a pu être efficacement menée grâce à l’utilisation de nouveaux précatalyseurs bien définis de manganèse à base de ligands bidentes facilement accessibles tels que la pyridinyl-phosphine et la 2-picolylamine. Dans la continuité de notre intérêt pour le développement de nouveaux catalyseurs à base de métaux du groupe 7, une série de complexes de rhénium coordinés à des ligands amino-bisphosphino a montré une excellente aptitude à promouvoir l’hydrogénation de composés carbonylés (aldéhydes, cétones), la mono-méthylation sélective d’amines avec le méthanol comme agent de méthylant durable et la synthèse quinolines substituées. La dernière partie de se travail décrit le développement d’oxydations aérobies d’amines pour préparer des aldimines, des composés N-hétéroaromatiques et des dérivés de type benzoimidazole via une catalyse au manganèse en l’absence de ligands ou d’additifsThis research work is aimed at developing advanced eco-friendly methodologies in the area of iron, manganese and rhenium-catalyzed (de)hydrogenation and hydroelementation reactions. Initially, we reported the first examples of highly selective catalytic direct C-H borylation of styrene derivatives and terminal alkynes with pinacolborane using Fe(PMe3)4 and Fe(OTf)2/DABCO as catalyst systems, respectively. Afterwards, N-heterocyclic carbene (NHC) based iron complexes Fe(CO)4(IMes) and [CpFe(CO)2(IMes)][I] were efficiently employed in the catalytic reductive amination reactions with hydrosilanes to access a large variety of cyclic amines (pyrrolidines, piperidines and azepanes). Interestingly, with the commercially available Mn2(CO)10 or Re2(CO)10 as catalyst and Et3SiH as an inexpensive hydrosilane source, carboxylic esters, acids and amides can be chemospecifically reduced to the corresponding acetals, alcohols and amines. Besides hydrosilylation, we also explored the application of a series of well-defined manganese pre-catalysts featuring readily available bidendate pyridinyl-phosphine and 2-picolylamine ligands in hydrogenation reactions of aldehydes, ketones and aldimines. In line with our interest in developing group 7 metals based catalysts, we have also demonstrated that a series of amino-bisphosphino ligands coordinated rhenium catalysts can efficiently promote the hydrogenation of carbonyl derivatives, the mono N-methylation of anilines with methanol and the dehydrogenative synthesis of substituted quinolines. Lastly we also developed the Mn-catalysed ligand- and additive-free aerobic oxidation of amines to prepare aldimines, N-heteroaromatics and benzoimidazole derivatives
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Calmus, Laurent. „Catalyse au fer : synthèse de 2H-chromènes, synthèse de métachromines“. Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066397.
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La mise au point de nouvelles méthodes de synthèse permettant d'accéder à des produits biologiquement actifs en utilisant réactifs peu onéreux dans des conditions respectueuses de l'environnement est un enjeu majeur. Le motif 2H-chromène est présent dans un grand nombre de molécules naturelles, et notamment dans plusieurs métachromines. Les métachromines sont des méroterpénoïdes naturels possédant des propriétés biologiques intéressantes. Notre étude s'est portée sur le développement d'une méthode de synthèse permettant d'accéder à des 2H-chromènes hautement fonctionnalisés par une réaction de cyclisation catalysée par des complexes de fer(III) à partir d'alcools allyliques phénoliques ainsi que l'application de cette méthode à la synthèse de produits naturels.Dans une première partie, cette méthode a été appliquée à des alcools allyliques phénoliques mono-, di-, tri-, ou tétra-substitués, pour conduire aux 2H-chromènes de manière efficace. L'étude de cette méthode a montré qu'un grand nombre de fonctionnalités étaient tolérées et qu'il était possible de moduler la réactivité des alcools allyliques phénoliques par la substitution du cycle aromatique et de la double liaison allylique. Cette méthode a été utilisée efficacement comme étape-clé dans la première synthèse totale de la téphrowatsine B, un 2H-chromène naturel issu d'une plante équatoriale présentant des propriétés insecticides. Dans une seconde partie, la première synthèse totale des métachromines J et T a été abordée. Notre méthode a été utilisée comme étape-clé pour accéder à un fragment 2H-chromène, précurseur commun de ces molécules. La synthèse totale de la métachromine C a également été étudiéeThe development of new synthetic methods, which could be used in the synthesis of biologically active compounds using inexpensive reactants and environmentally friendly conditions, is a major challenge in modern chemistry. 2H-Chromenes are present in a large number of biologically active compounds and especially in metachromins. Metachromins are natural marine meroterpenoids that present interesting biological activities. With these objectives in mind, our investigations were focused on the development of a synthetic method to access highly functionalised 2H-chromenes from readily accessible phenolic allylic alcohols, catalysed by iron(III) complexes as well as applications to the synthesis of various natural products. At the beginning, this method was applied to mono-, di-, tri- and tetra-substituted phenolic allylic alcohols to efficiently access the corresponding 2H-chromenes. This method tolerated a large number of functionalities and it was possible to modulate the reactivity of the substrates by substituting the aromatic ring and/or the allylic double bond. This method was applied as a key step in the first total synthesis of tephrowatsin B, a natural 2H-chromene isolated from an equatorial plant having insecticidal activities. On the other hand, the first total synthesis of metachromin J and T was investigated. Our method was used as a key step to access their 2H-chromene fragment, a common precursor of these molecules. The total synthesis of metachromin C was also studied
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Guérin, Nicolas. „Fonctionnalisation du chrysotile avec du fer pour fins de catalyse“. Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25608/25608.pdf.
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Trehoux, Alexandre. „Synthèse de complexes binucléaires de fer pour activation réductrice du dioxygène : vers de nouveaux catalyseurs d'oxydation bio-inspirés“. Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS052/document.
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Ces travaux décrivent la synthèse et l'étude de la réactivité de complexes binucléaires à fer, développés dans le but de mimer l'activité catalytique d'enzymes binucléaires à fer telles que la méthane monooxygénase soluble. Nous avons synthétisé et caractérisé plusieurs complexes binucléaires à fer(III), possédant différents types de groupements (électro-donneurs, électro-attracteurs, donneurs de liaison hydrogène) dans leur seconde sphère de coordination, de façon symétrique ou dissymétrique. Nous avons étudié l'influence de la seconde sphère de coordination de ces différents complexes sur les différents intermédiaires formés (notamment l'intermédiaire µ-peroxo-FeIIIFeIII) lorsque que ces complexes sont exposés au peroxyde d'hydrogène. Nous avons également étudié la capacité de ces différents complexes à catalyser les réactions d'oxydation de différents substrats (sulfures, alcènes et alcanes) par le peroxyde d'hydrogène, en absence et en présence d'eau dans le milieu réactionnel. Une modification intéressante de la chimiosélectivité de la réaction d'oxydation du cyclooctène par le peroxyde d'hydrogène, en présence d'un complexe binucléaire à fer dissymétrique et d'eau dans le milieu réactionnel a été observée. Différentes études d'aspect mécanistique ont été réalisées afin de déterminer l'origine des différents phénomènes observés en catalyse d'oxydationThis work describes the synthesis and the study of the reactivity of diiron complexes, developed in order to mimic the catalytic activity of diiron enzymes such as the soluble methane monooxygenase. We synthesized and characterized several diiron(III) complexes, bearing different types of groups (electron-donating, electron-withdrawing, hydrogen bond donating) in their second coordination sphere, in a symmetrical or non-symmetrical way. We studied the influence of the second coordination sphere of these different complexes over the different intermediates (particularly the µ-peroxo-FeIIIFeIII intermediate) formed by exposing them to hydrogen peroxide. We also studied the ability of these complexes to catalyze the oxidation of various substrates (sulfurs, alkenes, alkanes) by hydrogen peroxide, in absence or in presence of water in the reaction mixture. An interesting modification of chemoselectivity was observed in the case of oxidation of cyclooctene by hydrogen peroxyde, catalyzed by a non-symmetrical diiron complex, in presence of water in the reaction mixture. Several mechanistic studies were performed in order to investigate on the origin of the phenomenons we observed during oxidation catalysis studies
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Ahr, Mathieu. „Réactions d'homocouplage de composés organomagnésiens aromatiques en présence de sels de fer“. Cergy-Pontoise, 2004. http://www.theses.fr/2004CERG0207.
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Une nouvelle réaction d'homocouplage d'organomagnésiens aromatiques a été développée. Elle est effectuée en présence de sels de fer et d'un halogénure organique qui joue le rôle d'oxydant. Un mécanisme a été proposé et discuté. L'utilisation de 1,2-dihalogénoéthanes comme oxydants a permis d'effectuer la réaction d'homocouplage de phénylmagnésiens substitués en para, méta ou ortho par divers groupes fonctionnels (méthyle, méthoxy, fluoro, diméthylamino, carbéthoxy, cyano) pour conduire aux biphényles correspondants avec de bons rendements. La 3,3'-bipyridine et la 2,2'-difluoro-3,3'-dicarbéthoxy-4,4'-bipyridine ont également été préparées selon cette méthode. La réaction a été appliquée au couplage intramoléculaire de dimagnésiens aromatiques qui conduit à la formation de cycles à 5, 6 et 8 chaînons. Enfin, la synthèse totale de la N-méthylcrinasiadine a été effectuée en utilisant la réaction de couplage intramoléculaire comme étape cléA new homocoupling reaction of aryl Grignard reagents was developed. It takes place in the presence of iron salts and a organic halide which is used as an oxidant. A mechanism was proposed and discussed. Using 1,2-dihalogenoethanes as oxidant reagents, the homocoupling reaction of para-, meta- and ortho- subtitued by various functionalysed aryl Grignard reagents leads the corresponding biphenyls in good yields. 3,3'-bipyridine and 2,2'-difluoro-3,3'-dicarbethoxy-4,4'-bipyridine were also prepared. This reaction was used to perform intramolecular coupling reactions to create rings of 5, 6 and 8 atoms. At last, the total synthesis of N-methylcrinasiadine was completed using the intramolecular coupling reaction as the key step
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Lepori, Clément. „Complexes de fer(II) et de cobalt(II) de basse coordinance : synthèses, caractérisations et applications en réaction d’hydroamination des alcènes“. Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS509.
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Les motifs azotés sont présents dans de nombreuses molécules d’intérêts pharmaceutiques. Les méthodes de synthèses traditionnelles de ces motifs vont, par exemple, de la substitution nucléophile d’amines sur des halogénures d’alkyles à de l’amination réductrice des composés carbonylés. Ces méthodes, bien qu’efficaces, nécessitent néanmoins des quantités stœchiométriques de réactifs pour être appliquées et génèrent souvent des quantités importantes de déchets. Un des challenges de la chimie organique moderne consiste à développer de nouvelles méthodes de synthèses de ces motifs plus économiques et plus respectueuses de l’environnement en produisant un taux de déchets le plus faible possible. L’addition directe d’une amine sur une double liaison carbone-carbone non-activée que l’on appelle la réaction d’hydroamination des alcènes est une approche très prometteuse pour le développement d’une méthodologie de synthèse alternative de ces composés. En effet, dans cette réaction, tous les atomes du substrat de départ sont transférés au produit réduisant ainsi considérablement les déchets produits. De plus, les amines et les oléfines employées sont des réactifs relativement bon marché, abondants et variés. Néanmoins, cette transformation a priori simple nécessite généralement l’emploi d’un catalyseur. Dans la littérature, la réaction d’hydroamination des alcènes a été étudiée en utilisant comme catalyseur des complexes de métaux alcalins, alcalino-terreux, de terre-rares et de métaux de transition. Au commencement de ce projet, il n’existait pas d’exemples de réaction d’hydroamination des alcènes mettant en jeu des amines primaires non protégées catalysée par des complexes de fer ou de de cobalt. Dans ce contexte, notre équipe s’est intéressée à la réactivité de complexes de fer(II) et de cobalt(II) de basse valence stabilisés par des ligands de type β-dicétiminate. Ces complexes se sont révélés être d’excellents catalyseurs pour promouvoir la réaction d’hydroamination des amines primaires non protégées liées à des alcènes non activés.Dans un premier temps, les synthèses des complexes de fer(II) et de cobalt(II) alkyles stabilisés par des ligands β-dicétiminates ainsi que leurs applications en réaction de cyclohydroamination des amines primaires non protégées seront présentées. De plus, des études mécanistiques poussées permettront d’éclaircir le mécanisme de la réaction, qui est proposé de passer par une étape élémentaire clé d’insertion 1,2 migratoire aboutissant à la formation d’une liaison carbone-azote.Dans un second temps, les influences des propriétés électroniques et stériques des ligands sur la réactivité en réaction d’hydroamination des alcènes des complexes de fer(II) alkyles seront étudiées. Nous nous attarderons particulièrement sur des complexes stabilisés par des ligands β-dicétiminates dissymétriques ou iminoanilidures. Les données cristallographiques des complexes à l’état solide permettront alors de rationaliser les variations de réactivités de ces différents complexes.Enfin, les complexes de fer(II) et de cobalt(II) synthétisés précédemment seront exploités pour développer de nouvelles réactivités en réactions d’oxydation, d’amination oxydante ou de création de liaison azote-silicium par un couplage déshydrogénantThe nitrogenous units are present in many molecules of pharmaceutical interest. The traditional synthesis methods of these units range, for example, from the nucleophilic substitution of amines on alkyl halides to reductive amination of the carbonyl compounds. These methods, although effective, nevertheless require stoichiometric amounts of reagents to be applied and often generate large amounts of waste. One of the challenges of modern organic chemistry is to develop new methods of synthesizing these more economical and environmentally friendly patterns by producing the lowest waste rate possible. The direct addition of an amine to an unactivated carbon-carbon double bond known as the alkene hydroamination reaction is a very promising approach for the development of an alternative synthesis methodology for these compounds. Indeed, in this reaction, all the atoms of the starting substrate are transferred to the product thus considerably reducing the waste produced. In addition, the amines and olefins employed are relatively inexpensive, abundant and varied reagents. Nevertheless, this simple transformation generally requires the use of a catalyst. In the literature, the hydroamination reaction of alkenes has been studied using alkali metal, alkaline earth, rare earth and transition metal complexes as catalysts. At the beginning of this project there were no examples of the hydroamination reaction of alkenes involving unprotected primary amines catalysed by iron or cobalt complexes. In this context, our team was interested in the reactivity of iron (II) and cobalt (II) complexes of low valence stabilized by β-diketiminate ligands. These complexes have proved to be excellent catalysts for promoting the hydroamination reaction of unprotected primary amines bound to non-activated alkenes.In a first step, the syntheses of the iron (II) and cobalt (II) complexes stabilized by β-diketiminate ligands as well as their applications in cyclohydroamination reaction of the unprotected primary amines will be presented. In addition, advanced mechanistic studies will clarify the mechanism of the reaction, which is proposed to go through a key elementary 1..2 migratory insertion leading to the formation of a carbon-nitrogen bond.In a second step, the influence of the electron and steric properties of the ligands on the reactivity in the hydroamination reaction of the alkenes of the iron (II) alkyl complexes will be studied. We will focus particularly on complexes stabilized by asymmetric β-diketiminate ligands or iminoanilides. The crystallographic data of the solid state complexes will then make it possible to rationalize the variations of reactivities of these various complexes.Finally, the iron (II) and cobalt (II) complexes synthesized above will be exploited to develop new reactivities in oxidation reactions, oxidative amination or the creation of a nitrogen-silicon bond by a dehydrogenating coupling
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Jollet, Véronique. „Complexes de fer bio inspirés pour la catalyse d'oxydation : systèmes homogènes et supportés“. Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00915279.
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Certaines métalloenzymes catalysent l'oxydation de petites molécules organiques, dans des conditions douces (par activation du dioxygène à température et pression ambiante). Ce travail a pour but d'améliorer l'utilisation et l'efficacité catalytique des complexes de fer mimant cette activité.D'abord, par fonctionnalisation du ligand, un des complexes les plus efficaces pour catalyser l'oxydation de substrats aromatiques par H2O2, a pu être greffé dans des mésopores de silice. Ce matériau est utilisé comme support de catalyseur, en raison de sa grande surface spécifique et de sa chimie de surface versatile. Par ailleurs, la méthode de synthèse permet de structurer la taille des cavités formées, à l'aide d'un surfactant utilisé comme modèle. Le contrôle du nombre de sites catalytiques sur la surface est rendu possible par la procédure qui exploite le concept du pochoir moléculaire. Le confinement du catalyseur dans les pores pourrait être mis à profit pour former des produits à haute valeur ajoutée. En parallèle, ce complexe a aussi été greffé sur des billes de silices, un matériau moins élaboré pouvant être utilisé pour la dégradation de polluants. L'élaboration de ce type de catalyseurs supportés a nécessité de nombreuses caractérisations : analyses élémentaires, spectroscopies RMN, IR, XPS, UV-vis, RPE, isotherme d'adsorption d'azote, ATG, DRX sur poudre. Différentes méthodes de greffage ont été ainsi développées, et leur efficacité a été comparée. L'activité en catalyse d'oxydation de ces différents systèmes a aussi été évaluée.Concernant le développement des catalyseurs homogènes, le renforcement des positions des pyridines du ligand a permis l'obtention de nouveaux complexes de fer, possédant une meilleure stabilité pour réaliser des réactions catalytiques en milieu homogène et des propriétés structurales, spectroscopiques, chimiques et catalytiques analogues aux complexes de la même famille.Enfin, un autre complexe de fer a été mis en jeu dans un procédé électrochimique utilisant le dioxygène en présence de protons pour catalyser l'hydroxylation de substrats aromatiques.
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Nicolas, Irène. „Cyclopropanation asymétrique catalysée par les métalloporphyrines (fer et ruthénium)“. Rennes 1, 2009. http://www.theses.fr/2009REN1S129.
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The development of environmentally benign reactions is an important goal in synthetic organic chemistry and chemical engineering. However, catalytic enantioselective reactions using transition-metal complexes in protic or aqueous solvents are within limited ranges. Since we previously observed that some ruthenium porphyrin carbene complexes were stable in presence of hydrophilic solvent, such as methanol, we are interested in exploring the possibility that these complexes may also catalyze cyclopropanation in water and alcohols. Accordingly, we reveal herein that not only ruthenium porphyrins but also chiral water soluble iron porphyrins can be prepared and are indeed efficient catalysts for asymmetric cyclopropanation in water. In parallel, and in order to extend the scopes of application of these metalloporphyrins (Fe, Ru) as catalysts, we are interested in the synthesis of cyclopropylketones. The asymmetric addition of diazoketone to styrene derivatives to give optically active cyclopropylketones (ee up to 86%) was carried out by using chiral ruthenium porphyrins as homogeneous catalysts, offering for the first time, a general access to optically active cyclopropylketonesDe nos jours le développement durable est devenu une des principales préoccupations des chimistes. Toutefois, les réactions catalytiques énantiosélectives utilisant des complexes de métaux de transition dans des solvants aqueux restent limitées. Pourtant nous avons mis en évidence que des complexes ruthénium-carbène sur des porphyrines pouvaient être stables en présence de solvants protiques. Nous nous sommes donc intéressés à la possibilité d’utiliser ces complexes mais également de développer de nouveaux catalyseurs chiraux hydrosolubles pour des réactions de cyclopropanations. Nos résultats ont montré que les porphyrines de ruthénium et de fer sont des catalyseurs efficaces pour la cyclopropanation asymétrique dans l'eau conduisant même, dans certains cas, à de meilleurs excès énantiomériques. En parallèle, et afin d'étendre les domaines d’applications de ces métalloporphyrines (Fe, Ru) comme catalyseurs, nous nous sommes intéressés à la synthèse de cyclopropyles cétones. Nous avons démontré lors de notre étude que l'addition asymétrique de la diazocétone sur des dérivés du styrène donne des excès énantiomériques allant jusqu'à 86% offrant pour la première fois un accès direct aux cyclopropyles cétones optiquement actives
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Thibon, Aurore. „Complexes de fer non-hémiques, modèles de catalyseurs d’oxydation biologiques. Synthèses et caractérisations de complexes fer oxo et fer hydroperoxo. Utilisation en catalyse d’hydroxylation d’hydrocarbures aromatiques“. Paris 11, 2007. http://www.theses.fr/2007PA112152.
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Ce travail s’inscrit dans le cadre de la modélisation fonctionnelle de monooxygénases à fer capables d’hydroxyler les hydrocarbures aromatiques. La synthèse de différents ligands hexadentes de type amino-pyridine et d’un ligand de type macrocyclique a permis l’obtention et la caractérisation de nouveaux complexes de Fe(II) qui sont le point de départ de ce travail. L’action de divers oxydants, tels que des peroxydes, mCPBA ou le dioxygène sur ces précurseurs de Fe(II) a été étudiée à différentes températures et dans différents solvants. Des intermédiaires de type Fe(IV)O, Fe(III)OOH et Fe(III)(O2) ont été obtenus et identifiés. Ces différents complexes de Fe(II) se sont également révélés capables de catalyser l’hydroxylation de composés aromatiques par H2O2. L’ajout d’un réducteur a dans certains cas permis l’amélioration des rendements en produits d’oxydation. L’isolation de l’espèce [(L52)Fe(III)OOH]2+ sous forme solide a permis d’effectuer une étude mécanistique de l’hydroxylation des aromatiquesThe aim of this work is the functional modeling of iron monooxygenases. Among these biological systems, some are able to hydroxylate aromatic hydrocarbons. New Fe(II) complexes bearing hexadentate amine pyridine ligands or a pentadentate macrocyclic ligand with a pendant pyridine have been synthesized and characterized. The reaction of these Fe(II) precursors in presence of oxidants or oxidizing agents (peroxides, mCPBA, dioxygen) has been studied in different solvents at different temperatures. High valent Fe(IV)(O) intermediate and peroxo complexes (Fe(III)OOH and Fe(III)(O2)) have been obtained and identified. It has also been shown that these Fe(II) precursors are efficient catalyst for the hydroxylation of aromatic hydrocarbons by H2O2. In some instance, the presence of a reducing agent as a cofactor improves the yields in oxidation products. The obtention of [(L52)Fe(III)OOH]2+ as a microcrystalline powder has allowed to perform a mechanistic study of the hydroxylation of aromatics
Bücher zum Thema "Catalyse de fer"
1
National Symposium on Catalysis (8th 1987 Sindri, India). Challenges in catalysis science and technology: Proceedings of the 8th National Symposium on Catalysis held at Sindri during Feb. 12-14, 1987 under the joint auspices of Projects and Development India Limited and Catalysis Society of India. Sindri: Projects & Development India, 1987.
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2
National Symposium on Catalysis (8th 1987 Sindri, India). Challenges in catalysis science and technology: Proceedings of the 8th National Symposium on Catalysis held at Sindri during Feb. 12-14, 19 87, under the joint auspices of Projects and Development India Limited and Catalysis Society of India. Sindri: Projects & Development India Ltd., 1987.
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Meunier, Florent. Réactions d'oxydation catalysées par des complexes de ruthénium et de fer. Grenoble: A.N.R.T. Université Pierre Mendès France Grenoble 2, 1986.
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Patricia, Peppin, McCreary Bruce D, Stanton Barbara, Queen's University (Kingston, Ont.). Developmental Consulting Program. und Queen's University (Kingston, Ont.). Division of Developmental Disabilities., Hrsg. Catalysts for university education in developmental disabilities. [Kingston, Ont.]: Developmental Consulting Program, Queen's University, 2001.
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5
National Institutes of Health (U.S.). NCRR: A catalyst for discovery : a plan for the National Center for Research Resources. Bethesda, Md: NCRR, National Institutes of Health, 1994.
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Center, International Fertilizer Development, und CATALIST (Project), Hrsg. Proposition pour l'amelioration des recommandations pour la gestion integree de la fertilite des sols (GIFS) sur la base des resultats des tests participatifs et des demonstrations de fertilisation du projet CATALIST. Muscle Shoals, Ala: IDFC, 2012.
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Ferando, Christina. Exhibiting Antonio Canova. Nieuwe Prinsengracht 89 1018 VR Amsterdam Nederland: Amsterdam University Press, 2023. http://dx.doi.org/10.5117/9789463724098.
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Exhibiting Antonio Canova: Display and the Transformation of Sculptural Theory argues that the display of Canova’s sculptures in the late eighteenth and early nineteenth centuries acted as a catalyst for discourse across a broad range of subjects. By enshrining his marble figures alongside plaster casts of ancient works, bathing them in candlelight, staining and waxing their surfaces, and even setting them in motion on rotating bases, Canova engaged viewers intellectually, physically, and emotionally. These displays inspired discussions on topics as diverse as originality and artistic production, the association between the sculptural surface, flesh, and anatomy, the relationship between painting and sculpture, and the role of public museums. Beholders’ discussions also shaped the legacy of important sculptural theories. They helped usher in their modern definitions and created the lenses through which we experience and interpret works of art, establishing modern attitudes not just towards sculpture, but towards cultural patrimony in general.
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Davis, Burtron H. Fischer-Tropsch Synthesis, Catalysts, and Catalysis: Advances and Applications. Taylor & Francis Group, 2016.
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Davis, Burtron H. Fischer-Tropsch Synthesis, Catalysts, and Catalysis: Advances and Applications. Taylor & Francis Group, 2016.
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Davis, Burtron H. Fischer-Tropsch Synthesis, Catalysts, and Catalysis: Advances and Applications. Taylor & Francis Group, 2016.
Den vollen Inhalt der Quelle findenBuchteile zum Thema "Catalyse de fer"
1
Duan, Lunbo, und Lin Li. „Oxygen Carrier Aided Gasification (OCAG)“. In Oxygen-Carrier-Aided Combustion Technology for Solid-Fuel Conversion in Fluidized Bed, 79–96. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-9127-1_5.
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AbstractGasification is regarded as an effective clean utilization technology of solid fuel, which can convert the chemical energy of solid fuel into gaseous fuel. However, the primary gas products contain not only the essential gas products, but also an unacceptable amount of tars, which will cause operational problems such as blockage of downstream equipment during gasification. Catalysts are often used after the gasifier to catalyze tar in the pyrolysis product gas. However, the activity ofcatalysts generally declines over time, as they will be poisoned by prolonged exposure to an atmosphere containing elements such as sulfur, chlorine and alkali metals. In addition, under the condition of high tar content, carbon deposition may form on the surface of catalyst, which leads to the deactivation of catalyst. The oxygen carrier particles of natural ores not only can transport oxygen, but also contain various metal elements that can be used as catalysts for tar cracking. Introduce the OCs to replace inert bed materials may not only provide a cheap catalyst for the technology, but also complete the transfer of oxygen between the two reactors, this process is oxygen carrier aided gasification (OCAG).
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Terpstra, Marten. „Various Compositions Mainly Used as Catalysts or Catalyst Components“. In Materials for Refractories and Ceramics, 44–55. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4325-4_8.
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Knözinger, H. „Metal Clusters and Particles as Catalyst Precursors and Catalysts“. In Cluster Models for Surface and Bulk Phenomena, 131–49. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4684-6021-6_12.
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Bobrov, N. N., und V. N. Parmon. „Rapid Catalyst Testing in The Boreskov Institute of Catalysis“. In Principles and Methods for Accelerated Catalyst Design and Testing, 197–215. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-010-0554-8_10.
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Zhang, Huanjun, Guohua Chen und Detlef W. Bahnemann. „Environmental Photo(electro)catalysis: Fundamental Principles and Applied Catalysts“. In Electrochemistry for the Environment, 371–442. New York, NY: Springer New York, 2009. http://dx.doi.org/10.1007/978-0-387-68318-8_16.
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Arvidsson, Niklas. „Overall conclusions this far“. In People as Care Catalysts, 127–29. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2015. http://dx.doi.org/10.1002/9781119207818.ch8.
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Hermanns, Ellen, Jens Hasenjäger und Birgit Drießen-Hölscher. „PEG-Modified Ligands for Catalysis and Catalyst Recycling in Thermoregulated Systems“. In Regulated Systems for Multiphase Catalysis, 53–66. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/3418_2006_061.
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Berman, Carol W. „Fear: The Catalyst That Breaks Through Denial“. In Surviving Dementia, 7–11. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-35102-5_2.
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Schmiermund, Torsten. „Catalysis“. In The Chemistry Knowledge for Firefighters, 437–45. Berlin, Heidelberg: Springer Berlin Heidelberg, 2022. http://dx.doi.org/10.1007/978-3-662-64423-2_36.
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Figueiredo, Jośe Lúís, und Manuel Fernando R. Pereira. „Carbon as Catalyst“. In Carbon Materials for Catalysis, 177–217. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2008. http://dx.doi.org/10.1002/9780470403709.ch6.
Der volle Inhalt der QuelleKonferenzberichte zum Thema "Catalyse de fer"
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Kang, Inyong, und Joongmyeon Bae. „Study on Autothermal Reforming of Diesel“. In ASME 2005 3rd International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2005. http://dx.doi.org/10.1115/fuelcell2005-74063.
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Diesel is one of the best hydrogen storage systems, which has very high volumetric density [kg H2/m3] (>100) and gravimetric density [%H2] (>15). Several catalysts were selected for diesel reforming. 3 catalysts (Pt on gadolinium doped ceria, Rh and Ru on the same support, Patent for catalyst formulation of Argonne National Laboratory in U.S.A) and 2 commercial catalysts (FCR-HC14 and FCR-HC35, Su¨d-Chemie, Inc.) were used to reform diesel. Pt catalyst showed the best performance. Effects of operating conditions such as temperature, O2/C and H2O/C on ATR (autothermal reforming) were investigated. In addition, we studied on reaction characteristics for better understanding about ATR reaction by analyzing concentrations of products and temperature profiles along catalyst bed. We found key issues such as fuel delivery and heat transfer between front exothermic part and rear endothermic part of catalyst bed.
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Lobato, J., P. Can˜izares, M. A. Rodrigo, J. J. Linares und B. Sa´nchez-Rivera. „Testing Different Catalysts for a Vapor-Fed PBI-Based Direct Ethanol Fuel Cell“. In ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2009. http://dx.doi.org/10.1115/fuelcell2009-85055.
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With the aim of improving the ethanol oxidation in fuel cells, researchers have developed numerous catalysts to break up the C-C bond. Most of the tests have been carried out at low temperature, using Nafion membrane as electrolyte. The cell performance of the Direct Ethanol Fuel Cells (DEFCs) at low temperature is still far from its industrial application. To improve the DEFC power density, high temperature operation (150–200 °C) has been suggested to promote the complete oxidation of ethanol. Thus, three different catalysts (Pt-Ru (1:1), Pt-Sn (1:1) and Pt-Sn-Ru (1:1:0.3), all of them supported on both non-activated and activated carbon were tested in H3PO4 doped PBI-based fuel cell, using vapour fed ethanol, operating in the range of 150–200 °C, and high ethanol concentration 6.7 M. The catalyst were synthesized using NaBH4 as reducing agent and were characterized by XRD, ICP-AES and TPR analyses. The best performance was reached at the highest temperature and with the catalyst based on Pt-Ru. The best results for the Ru-based catalyst can be explained by the higher level of alloying reached for the Ru than for Sn, which modifies the crystalline structure of Pt and enhances the activity oxidation of ethanol and of intermediates that are generated during the oxidation of ethanol.
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Wu, Quanwen, Wenhua Luo, Daqiao Meng, Jinchun Bao und Jingwen Ba. „High Efficient Detritiation Catalysts for Fusion Safety“. In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-81269.
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Tritium is indispensable to the fusion reactor engineering, and it must be seriously defended because of its radioactivity and permeability. The method of catalytic oxidation and absorption is the most widely used process for tritium cleanup so far, in which detritiation catalyst is of great importance. The poor stability caused by the agglomeration of noble metal limits the life of detritiation catalysts. Here, Anti–Ostwald Ripening is used to prepare single-atom detritiation catalysts S-Pt/Ce0.7Zr0.3O2 for tritium (HT, DT and T2) oxidation. Single-atom dispersed Pt ensures the catalytic activity and decreased the economic cost. The strong metal-support interaction (SMSI) keeps Pt from aggregating, thus increases the working life of catalyst. And Pd based catalyst supported by a cation ordered κ-Ce2Zr2O8 is prepared for tritiated methane (CH4-xTx) oxidation. Tritiated methane is mostly oxidized by Pd/κ-Ce2Zr2O8 at about 450 °C, which is at least 50 °C lower than normal catalysts (such as Pd/Al2O3).
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Prikhodko, Vitaly Y., Josh A. Pihl, Samuel A. Lewis und James E. Parks. „Effect of Hydrocarbon Emissions From PCCI-Type Combustion on the Performance of Selective Catalytic Reduction Catalysts“. In ASME 2011 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/icef2011-60129.
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Core samples cut from full size commercial Fe- and Cu-zeolite SCR catalysts were exposed to a slipstream of raw engine exhaust from a 1.9-liter 4-cylinder diesel engine operating in conventional and PCCI combustion modes. Subsequently, the NOx reduction performance of the exposed catalysts was evaluated on a laboratory bench-reactor fed with simulated exhaust. The Fe-zeolite NOx conversion efficiency was significantly degraded, especially at low temperatures (<250°C), after the catalyst was exposed to the engine exhaust. The degradation of the Fe-zeolite performance was similar for both combustion modes. The Cu-zeolite was much more resistant to HC fouling than the Fe-zeolite catalyst. In the case of the Cu-zeolite, PCCI exhaust had a more significant impact than the exhaust from conventional combustion on the NOx conversion efficiency. For all cases, the clean catalyst performance was recovered after heating to 600°C. GC-MS analysis of the HCs adsorbed to the catalyst surface provided insights into the observed NOx reduction performance trends.
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Jayasuriya, Jeevan, Arturo Manrique, Reza Fakhrai, Jan Fredriksson und Torsten Fransson. „Experimental Investigations of Catalytic Combustion for High-Pressure Gas Turbine Applications“. In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90986.
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Catalytic combustion has proven to be a suitable alternative to conventional flame combustion in gas turbines for achieving Ultra-Low Emission levels (ULE). In the process of catalytic combustion, it is possible to achieve a stable combustion of lean fuel/air mixtures which results in reduced combustion temperature in the combustor. The ultimate result is that almost no thermal-NOx is formed and the emissions of carbon monoxide and hydrocarbon emissions are reduced to single-digit limits. Successful development of catalytic combustion technology would lead to reducing pollutant emissions in gas turbines to ultra-low levels at lower operating costs. Since the catalytic combustion prevents the pollutant formations in the combustion there is no need for costly emission cleaning systems. High-quality experimental data of combustion catalyst operations at gas turbine working conditions and validated numerical models are essential tools for the design and development of catalytic gas turbine combustors. The prime objective of the work presented in this paper was to obtain catalytic operational data under said conditions. Experimental investigations were carried out to determine the operational data on different types of combustion catalysts against different fuel types at gas turbine operational conditions. A pilot-scale 100 k W high-pressure combustion test facility was used for the experimental investigations of catalytic combustion under real gas turbine conditions. Combustor pressure can be maintained at any desired level between 1 to 35 bars. The maximum combustion air supply is 100 g/s, which can be electrically preheated up to 600°C and humidified up to 30% of weight as required by test conditions. Catalysts used in the test facility are highly active noble metal catalysts for ignition purposes and thermally stable metal oxide catalysts for continuing reactions. Tests are conducted as the testing of single catalyst segments or combinations of several segments. The measurements taken are flow rates (air/fuel ratio) temperatures (inlet, surface and the outlet of each catalyst segment), pressure (combustor) and emissions of NOx, CO and UHC. This paper presents the design of the high-pressure catalytic combustion test facility and an experimental comparison of methane combustion over Pd on alumina and Pd/Pt (bi-metal) on alumina catalysts at varying pressure levels up to 20 bars. The catalysts concerned were cylindrical shaped (35 mm in diameter and 20 mm in height) honeycomb type fully coated catalysts. The results showed that the Pt/Pd on alumina catalysts is better in low temperature ignition and combustion stability over the Pd on alumina catalysts. Emission measurements showed that the fuel conversion over the tested Pt/Pd on alumina catalyst was around 10% while fuel conversion over a similar Pd on alumina catalyst (geometry and capacity) was only 4%. Fuel conversion rates showed the tendency to be further reduced (over the same catalysts) against increasing pressure.
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Djimasbe, Richard, Mikhail A. Varfolomeev, Eduard A. Galiullin, Ameen A. Al-Muntaser, Bulat I. Gareev, Rail I. Kadyrov, Muneer A. Suwaid, Rustam R. Davletshin und Konstantin Yu Prochukhan. „Development and Assisted Injection of Sub- And Supercritical Water by the Oil-Soluble Catalysts for the Intensification of Upgrading Process of the Bazhenov Oil Shale and Production of Synthetic Oil“. In SPE/IATMI Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/215485-ms.
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Abstract In this paper, an EOR technology was proposed, including a development of oil soluble catalytic compositions and their injection with sub- and supercritical water (sub- and SCW) for in-situ hydrothermal upgrading of oil shale and intensifies the generation of synthetic oil. The experiments were carried with the oil shale sample from the Bazhenov formation (Russia) with 9.13% of the total organic carbon (TOC) which 83% composed of kerogen, at the sub- and SCW conditions of 300-400°C taking into account of the reservoir pressure ≥ 250 bars and with time (6-24h) in the presence and absence of catalysts. Combined methods have been used to characterize the catalysts, oil shale and assess the composition of the reaction products, are illustrated in the experimental section. Additionally, simulation software (Hysys v.12) was also used to calculate the heat load. In this study, the designation of the Kat-1 and Kat-2 refers to Nickel (Ni2+) based catalysts with the «vegetable oil» and «tall oil» as organic ligands, and the Kat-3 and Kat-4 refers to Iron (Fe3+) based catalysts with similar above organic ligands, respectively. The results of injection of sub- and SCW without catalyst showed that the maximum oil shale conversion reaches 52.46% at 350°C and 24h. Consequently, the higher synthetic oil yields of 29.22%, 43.59% and 9.75 % have been obtained after the non-catalytic upgrading process at temperatures of 300°C, 350°C, 400°C and time 24h, 6h and 6h, respectively. It has been established that an increase in reservoir pressure can lead to a proportional increase in yield of gas up to 2.74% at 400°C. Injection of sub- and SCW with oil soluble catalysts at temperatures of 300°C - 400 °C improves the oil shale upgrading and it reveals that the maximum organic maters conversion of 76.67% at 350°C was obtained using the Kat-1. Particularly, it has been found that due to high activity of nickel and considerable amount of π bonds in the ligand the catalyst, the Kat-2 exhibits good performance for upgrading reactions and generate the synthetic oil. Consequently, at an identical temperature of 350°C the yield of synthetic oil increased from 29.22% for the absence of a catalyst to 39.1% using the Kat-2. That means that the Kat-2 can increase more additionally 9.88% of synthetic oil also reducing 4 times the necessary time for the non-catalytic upgrading process. Moreover, at conditions of 350°C and 24h, around 214.06 kg additional of synthetic oil can be produced from a ton organic using Kat-1. Overall, it found that the catalysts (Kat-2 and Kat-4) show appropriate ability for synthetic oil production, while the catalysts (Kat-1 and Kat-3) selectively improve the quality of synthetic oil and the gas yields. Thus, the reasons for good selectivity of Kat-2 and Kat-4 for the synthetic oil production is not only attributed to the metals (Ni2+ and Fe3+) activities, but more to the types of the used ligand. The greater the number of pi bonds in the organic ligands of catalysts, the faster the catalyst is activated. We also observed that at a high temperature of 400°C, a significant decrease in the synthetic oil yield is possible, due to fast decomposition of kerogen into gas and polymerization of intermediate products to coke. According to the results of GC the obtained synthetic oil at the optimal conditions of (350°C, 6h, 24h and the Kat-3) most composed of gasoline - 6.95%, kerosene - 16.88%. It is revealed that the required amount of catalyst to upgrade a ton of Bazhenov organic potential is 13.42 kg, and the amount of sub- and SCW for injection is (8-10:1). After calculation, optimal energy load to reach optimal conversions (46.5% - 50.7%) is 2833 - 4250 kW/h. Thus, use of oil soluble catalysts for the synthetic oil production from the Bazhenov formation is potentially recommended, due to its ecological and has perspective for the exploitation of oil shale in Russia.
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Samsa, Žiga, Darja Pečar und Andreja Goršek. „Catalyzed Degradation of Polyethylene Terephthalate“. In International Conference on Technologies & Business Models for Circular Economy. University of Maribor Press, 2023. http://dx.doi.org/10.18690/um.fkkt.1.2023.5.
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In this research catalyzed degradation of polyethylene terephthalate was performed. For that purpose, ZSM-5 zeolite was synthesized as an acid catalyst. For its characterization N2 adsorption, scanning electron microscopy, NH3 temperature programmed desorption, differential scanning calorimetry, thermogravimetric analysis, dynamic light scattering, and Fourier transform infrared spectroscopy were utilized. Degradation reactions were performed in high pressure crucibles using differential scanning calorimeter at different temperatures (200, 250 and 300) °C and time intervals (2.5, 5, 10 and 15) min. Samples were analyzed using high performance liquid chromatography coupled with UV-VIS detector. The results revealed that the highest conversion was achieved at 300 °C and 10 min. The analysis of obtained results showed that despite the differences in conversions being not as high as expected, reactions with the catalyst were slightly more effective than without it. For the future work, we plan to finetune the synthesis procedure to obtain more active catalyst. And for the upgrade of the study the kinetic analysis of the reaction will be conducted.
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Harth, Florian M., Brigita Hočevar, Blaž Likozar und Miha Grilc. „A Novel Process to Produce Adipic Acid by Catalytic Dehydroxylation of Biomass-derived Mucic Acid“. In International Conference on Technologies & Business Models for Circular Economy. University of Maribor Press, 2022. http://dx.doi.org/10.18690/um.fkkt.3.2022.1.
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The heterogeneously catalyzed dehydroxylation of mucic acid to produce adipic acid, a highly relevant polymer precursor, was investigated. The use of methanol as solvent is particularly important since it not only acts as reducing agent but also protects the carboxylic acid functionality by esterification. Re/C was found a well-suited catalyst for this reaction and not only showed high activity but was also reusable with suitable reactivation procedure. Under optimized reaction conditions, 98 % of dehydroxylated products could be obtained from mucic acid. Moreover, combining Re/C with a suitable hydrogenation catalyst (e.g. Pd/C) and performing the reaction under H2 atmosphere steers the reaction towards adipic acid ester. Therefore, it could be shown that adipic acid derivatives are available from biomass-accessible mucic by this novel and renewable approach.
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V, Praveena, Rajarajeswari R und Deborah Stephen. „Enhancing the Performance of DOC and SCR After-Treatment Devices Using Statistical Techniques and Heating Strategies“. In International Conference on Advances in Design, Materials, Manufacturing and Surface Engineering for Mobility. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2023. http://dx.doi.org/10.4271/2023-28-0128.
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<div class="section abstract"><div class="htmlview paragraph">Exhaust gas emissions from compression ignition engines are the most hazardous contaminants to human beings as well as the atmosphere. This research work contributes to develop a combined technology that targets the reduction in HC, CO, smoke and NOx emissions collectively without any modification in engine fuel or injection strategy. Slight changes in the exhaust after- treatment system will help in meeting the goal of reduced standards. DOC and SCR devices fitted at the exhaust gas pipe reduces CO, HC, smoke, and NOx emissions produced by the CI engine. A combination of aluminum oxide- cerium oxide and iron oxide are used as SCR and DOC catalysts, whose preparation is done by impregnation method and their performance is tested on a SCR+DOC bed. The injection of aqueous urea solution is varied from 200 ml to 600 ml by intervals of 200 ml at different load conditions. Response parameters for various experiments are predicted using response surface methodology. Utilizing this novel combination of catalysts shows a reduction of 2.6% in CO, 2.2% in HC and 73.2% in NOx emissions. To enable the regeneration of catalysts, a heating strategy is implemented. This helps in replenishing the SCR and DOC bed which gets affected by repeated usage for a continuous period of time. The catalyst light-off temperature is reduced which overcomes the difficulty of operation in cold regions. A significant improvement in the after-treatment system is noticed by electrically heating the catalyst with an electrical power of 400 W. CO and HC emissions are reduced by 12.2% and 2.1% respectively.</div></div>
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Zhu, Yimin, Ionel Stefan, Baixin Qian, Jay Goldman, Jurgen Hofler und Jason Hartlove. „Inorganic-Nano-Fiber-Based Catalyst for Hydrogen Fuel Cells With Superior Performance“. In ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2009. http://dx.doi.org/10.1115/fuelcell2009-85130.
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In this paper we report on a novel, cost-effective fuel cell catalyst solution that meets performance as well as reliability goals set forth by the Department Of Energy for transportation applications for 2010. Our fuel cell catalyst technology is based on an inorganic, conductive nano-fiber network decorated with Pt or Pt-alloy nano-particles. The nano-fibers have diameters in the 10s of nanometers and aspect ratios of ∼100:1. The resulting large surface area, high chemical activity, and efficient electron and proton transport in the membrane electrode assembly (MEA) allow for ultra-low material loading at very high performance. Specifically, with a total loading (anode and cathode) of only 0.2mg/cm2, we have demonstrated a performance of 0.25g/kW at 0.65V exceeding the 2010 DOE goal of 0.3g/kW. We also met the DOE target for power density of 0.25 W/cm2 at 0.8V. Very important for practical applications, the initial reliability tests show that our inorganic nano-fiber-based catalysts have a lifetime performance far superior to carbon-based approaches.
Berichte der Organisationen zum Thema "Catalyse de fer"
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Olsen, Daniel, Bryan Hackleman und Rodrigo Bauza Tellechaea. PR-179-16207-R01 Oxidation Catalyst Degradation on a 2-Stroke Lean-Burn NG Engine - Washing. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), Mai 2019. http://dx.doi.org/10.55274/r0011586.
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Oxidation catalysts are often utilized to reduce carbon monoxide, formaldehyde, and volatile organic compounds in order to meet emissions regulations for large bore natural gas engines. These catalysts degrade over time and need to be replaced or regenerated to maintain emissions compliance. This work evaluates the effectiveness of catalyst regeneration, or catalyst washing. The evaluation is performed by utilizing field and laboratory slip streams combined with catalyst module performance (reduction efficiency) measurements and catalyst material surface analysis to quantify catalyst poisons.
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Stevens und Olsen. PR-179-12214-R01 CO Sensor Experimental Evaluation for Catalyst Health Monitoring. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), September 2014. http://dx.doi.org/10.55274/r0010827.
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Oxidation catalysts and three-way catalysts can be used to reduce the amount of CO present in engine exhaust. For 2-stroke lean-burn engines, the oxidation catalyst degrades over time be-cause of the buildup of poisons such as sulfur, zinc, phosphorous, and calcium. Three-way cata-lysts used with stoichiometric engines also degrade over time. Emissions analyzers are often used to evaluate the degradation of oxidation catalysts and three-way catalysts, but it can be very time consuming and expensive. Ideally, a simple sensor system would be beneficial for operating companies to determine if the catalyst were out of compliance according to normal operating standards. An ECM CO sensor and recording device was acquired for testing. The CO sensor system was evaluated for its ability to monitor post-catalyst CO concentration. The results show that this CO sensor system is ineffective at monitoring post-catalyst CO concentration.
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Badrinarayanan und Olsen. PR-179-11201-R01 Performance Evaluation of Multiple Oxidation Catalysts on a Lean Burn Natural Gas Engine. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), August 2012. http://dx.doi.org/10.55274/r0010772.
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Two-way catalysts or oxidation catalysts are the common after-treatment systems used on lean burn natural gas engines to reduce CO, VOCs and formaldehyde emissions. The study evaluates the performance of oxidation catalysts from commercial vendors for varying catalyst temperature and space velocity. For this study, a part of the exhaust from a Waukesha VGF-18 GL lean burn natural gas engine was flowed through a catalyst slipstream system to assess the performance of the oxidation catalysts. The slipstream is used to reduce the size of the catalysts and to allow precise control of temperature and space velocity. Analyzers used include Rosemount 5-gas emissions bench, Nicolet Fourier Transform Infra-Red spectrometer and HP 5890 Series II Gas Chromatograph. The oxidation catalysts were degreened at 1200oF (650oC) for 24 hours prior to performance testing. The reduction efficencies for the emission species varied among the oxidation catalysts tested from different vendors. Most oxidation catalysts showed over 90% maximum reduction efficiencies on CO, VOCs and formaldehyde. VOC reduction efficiency was limited by poor propane emission reduction efficiency at the catalyst temperatures tested. Saturated hydrocarbons such as propane showed low reduction efficiencies on all oxidation catalysts due to high activation energy. Variation in space velocity showed very little effect on the conversion efficiencies. Most species showed over 90% conversion efficiency during the space velocity sweep. Adding more catalyst volume may not increase the reduction efficiency of emission species. Varying cell density showed very little effect on performance of the oxidation catalysts. The friction factor correlation showed the friction factor for flow through a single channel is inversely proportional to cell density.
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Olsen und Neuner. PR-179-12207-R01 Performance Measurements of Oxidation Catalyst on an Exhaust Slipstream. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), August 2013. http://dx.doi.org/10.55274/r0010800.
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Oxidation catalysts are effective at reducing CO, formaldehyde, and VOCs as long as the catalyst temperature is above the light-off temperature for each species. It is important to understand the effects of temperature and space velocity on regulated species in order to effectively apply oxidation catalyst technology to lean burn engines, in particular 2-stroke engines that typically have lower exhaust temperatures. Various catalysts were tested on an exhaust slipstream coupled to a 4-stroke lean-burn engine which allows tests to be conducted at different temperatures and flow rates. The effect of the oxidation catalysts on NO2 and odor are also discussed.
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Defoort, Willson und Olsen. L51849 Performance Evaluation of Exhaust Catalysts During the Initial Aging on Large Industrial Engines. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), Juni 2001. http://dx.doi.org/10.55274/r0011213.
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An investigation of catalyst performance during the initial aging process, providing insight into the deactivation rate of the catalyst and assisting in predicting the operational lifetime of the catalyst was preformed. The information gained through the test program provides a mechanism to assist in developing new technologies geared at reducing engine emission while providing improvements in efficiency, reliability, and operability for the aging industrial reciprocating engine fleet. Two natural gas lean burn engines, a 2-stroke, large bore slow speed and a 4-stroke medium bore medium speed, were operated at pre-determined conditions in conjunction with an oxidation catalyst. The aging process of the catalysts was observed. The research concluded that the catalyst performance is much lower than anticipated,particularly in relation to the aging process. During the aging process for the large bore 2-stroke engine (about 200 hours) the catalyst efficiency drops from 95% to 80% for CO and from 75% to 45% for CH2O. Results for the medium bore 4-stroke engine are better as a result of nearly 200°F higher catalyst temperatures. During aging (approximately 150 hours) the catalyst efficiencies are reduced from 99.2 to 97.7% for CO and from undetectable post catalyst levels (essentially 100% removal) to 67% for CH2O.
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Swanson, Dr Larry, und Christopher Samuelson. PR-362-06208-R01 Evaluation of Byproduct Emissions from Gas Turbine SCR Catalyst. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), Februar 2009. http://dx.doi.org/10.55274/r0010978.
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The primary objective of the test program was to evaluate byproduct emissions at steady state and transient operating conditions for two commercially available SCR catalysts used in gas turbine applications. Both NOX removal efficiency and ammonia slip behavior were also examined to validate expected catalyst trends and activity. Even though the study replicated expected field catalyst process conditions as well as possible (e.g., flue gas temperatures, space velocities, and inlet species concentrations), the data and results are from pilot-scale testing only, and consequently may differ from actual gas turbine field tests.
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Bauza, Rodrigo, und Daniel Olsen. PR-179-20200-R01 Improved Catalyst Regeneration Process to Increase Poison Removal. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), Juni 2021. http://dx.doi.org/10.55274/r0012106.
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In this work, the details of catalyst poison deposition are studied, and new catalyst restoration methods are explored. Lubrication oil makes its way through the combustion chamber and into the exhaust system, depositing poisons onto the catalyst and degrading catalyst performance. To estimate the degradation rate of the units and to find the best restoration method, two identical alumina-platinum oxidation catalysts were used in a dual setting, combining a field degradation engine and a laboratory testing engine. In order to find the best restoration process, the combination of both baking and washing is tested with poison deposition and performance analysis, and a hydrogen reduction is tested for the restoration of the platinum crystallites. The units were aged, then restored with the industry-standard washing procedure, then aged again until reaching non-compliance with emissions standards, and then restored a second time with a modified version of the industry-standard washing process that combines baking and washing. There is a related webinar.
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Baumgardner, Davis und Olsen. PR-179-13205-R01 Field Evaluation of Oxidation Catalyst Degradation - 2-Stroke Lean-Burn NG Engine. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), Oktober 2015. http://dx.doi.org/10.55274/r0010036.
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This study examines the degradation of an exhaust oxidation catalyst on a Cooper-Bessemer GMVH 12C2 gas engine. Critical parameters were determined, such as light-off temperature and reduction efficiency at 450 and 600?F. The catalyst surface was analyzed to examine the location and rate of poison deposition. Catalyst life was examined based on NESHAP guidelines. Catalyst life is strongly dependent on catalyst temperature and space velocity. For similar industrial applications, if the engine unit particulars are known, site operators can use the information in this study to predict when the oxidation catalyst will need to be either replaced or regenerated (washed).
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Datye, A. K., M. D. Shroff, Y. Jin, R. P. Brooks, J. A. Wilder, M. S. Harrington, A. G. Sault und N. B. Jackson. Nanoscale attrition during activation of precipitated iron Fischer- Tropsch catalysts: Implications for catalyst design. Office of Scientific and Technical Information (OSTI), Juni 1996. http://dx.doi.org/10.2172/237416.
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MAVRIKAKIS, MANOS DUMESIC, JAMES A. CATALYSIS SCIENCE INITIATIVE: From First Principles Design to Realization of Bimetallic Catalysts for Enhanced Selectivity. Office of Scientific and Technical Information (OSTI), Mai 2007. http://dx.doi.org/10.2172/902903.
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