Bibliographies thématiques / Catalyse moderne

Littérature scientifique sur le sujet « Catalyse moderne »

Auteur : Grafiati
Publié le 20 juillet 2024

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Articles de revues sur le sujet "Catalyse moderne"

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Sambiagio, Carlo, Stephen P. Marsden, A. John Blacker et Patrick C. McGowan. « Copper catalysed Ullmann type chemistry : from mechanistic aspects to modern development ». Chem. Soc. Rev. 43, no 10 (2014) : 3525–50. http://dx.doi.org/10.1039/c3cs60289c.

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Copper-catalysed arylations represent valid and complementary alternatives to Pd catalysis. This review discusses the different mechanisms suggested for these reactions, and summarises some of their latest applications in synthesis.
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Mao, Zhenjun, Haorui Gu et Xufeng Lin. « Recent Advances of Pd/C-Catalyzed Reactions ». Catalysts 11, no 9 (7 septembre 2021) : 1078. http://dx.doi.org/10.3390/catal11091078.

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The Pd/C-catalyzed reactions, including reduction reactions and cross-coupling reactions, play an irreplaceable role in modern organic synthesis. Compared to the homogeneous palladium catalyst system, the heterogeneous Pd/C catalyst system offers an alternative protocol that has particular advantages and applications. Herein, a review on Pd/C-catalyzed reactions is presented. Both the advances in Pd/C-catalyzed methodologies and the application of Pd/C-catalysis in total synthesis are covered in this review.
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Costentin, Cyrille, Jean-Michel Savéant et Cédric Tard. « Ligand “noninnocence” in coordination complexes vs. kinetic, mechanistic, and selectivity issues in electrochemical catalysis ». Proceedings of the National Academy of Sciences 115, no 37 (24 août 2018) : 9104–9. http://dx.doi.org/10.1073/pnas.1810255115.

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The world of coordination complexes is currently stimulated by the quest for efficient catalysts for the electrochemical reactions underlying modern energy and environmental challenges. Even in the case of a multielectron−multistep process, catalysis starts with uptake or removal of one electron from the resting state of the catalyst. If this first step is an outer-sphere electron transfer (triggering a “redox catalysis” process), the electron distribution over the metal and the ligand is of minor importance. This is no longer the case with “chemical catalysis,” in which the active catalyst reacts with the substrate in an inner-sphere manner, often involving the transient formation of a catalyst−substrate adduct. The fact that, in most cases, the ligand is “noninnocent,” in the sense that the electron density and charge gained (or removed) from the resting state of the catalyst are shared between the metal and the ligand, has become common-place knowledge over the last half-century. Insistent focus on a large degree of noninnocence of the ligand in the resting state of the catalyst, even robustly validated by spectroscopic techniques, may lead to undermining the essential role of the metal when such essential issues as kinetics, mechanisms, and product selectivity are dealt with. These points are general in scope, but their discussion is eased by adequately documented examples. This is the case for reactions involving metalloporphyrins as well as vitamin B12 derivatives and similar cobalt complexes for which a wealth of experimental data is available.
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Li, Yongfei, Shu Zhang, Ying Wang, Guobin Qi, Tao Yu, Xin Xin, Bin Zhao et Gang Chen. « Oil-Soluble Exogenous Catalysts and Reservoir Minerals Synergistically Catalyze the Aquathermolysis of Heavy Oil ». Molecules 28, no 19 (22 septembre 2023) : 6766. http://dx.doi.org/10.3390/molecules28196766.

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Oil is the “blood” and economic lifeblood of modern industry, but traditional light crude oil has been over-consumed, and it has been difficult to meet human demand for energy, so the exploitation of heavy oil is particularly important. In this paper, an oil-soluble catalyst was synthesized to catalyze the pyrolysis reaction of heavy oil in collaboration with reservoir minerals, so as to achieve efficient viscosity reduction of heavy oil and reduce production costs. The experimental results showed that Zn(II)O + K had the best synergistic viscosity reduction effect after the aquathermolysis of No. 1 oil sample under the reaction conditions of 180 °C, 4 h, 30% of water, and 0.2% of catalyst, respectively, and the viscosity reduction rate was 61.74%. Under the catalysis of the isopropanol system, the viscosity reduction rate was increased to 91.22%. A series of characterizations such as freezing point, thermogravimetric analysis, DSC analysis, component analysis, gas chromatography, wax crystal morphology analysis, and GC-MS analysis of aqueous organic matter were carried out on heavy oil after reaction by different reaction systems, and it could be verified that the viscosity of heavy oil was reduced. Finally, through the study of the reaction mechanism of the model compound, combined with the aqueous phase analysis, it can be clearly found that the depolymerization between macromolecules, the breaking of heteroatom chains, hydrogenation, ring opening, and other effects mainly occur during the reaction, thereby weakening the van der Waals force and hydrogen bond of the recombinant interval, inhibiting the formation of grid structure in heavy oil and effectively reducing the viscosity of heavy oil.
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Wetchasat, Piraya, Saros Salakhum, Thidarat Imyen, Duangkamon Suttipat, Wannaruedee Wannapakdee, Marisa Ketkaew, Anittha Prasertsab, Pinit Kidkhunthod, Thongthai Witoon et Chularat Wattanakit. « One-Pot Synthesis of Ultra-Small Pt Dispersed on Hierarchical Zeolite Nanosheet Surfaces for Mild Hydrodeoxygenation of 4-Propylphenol ». Catalysts 11, no 3 (5 mars 2021) : 333. http://dx.doi.org/10.3390/catal11030333.

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The rational design of ultra-small metal clusters dispersed on a solid is of crucial importance in modern nanotechnology and catalysis. In this contribution, the concept of catalyst fabrication with a very ultra-small size of platinum nanoparticles supported on a hierarchical zeolite surface via a one-pot hydrothermal system was demonstrated. Combining the zeolite gel with ethylenediaminetetraacetic acid (EDTA) as a ligand precursor during the crystallization process, it allows significant improvement of the metal dispersion on a zeolite support. To illustrate the beneficial effect of ultra-small metal nanoparticles on a hierarchical zeolite surface as a bifunctional catalyst, a very high catalytic performance of almost 100% of cycloalkane product yield can be achieved in the consecutive mild hydrodeoxygenation of 4-propylphenol, which is a lignin-derived model molecule. This instance opens up perspectives to improve the efficiency of a catalyst for the sustainable conversion of biomass-derived compounds to fuels.
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Khairulin, Sergei, Mikhail Kerzhentsev, Anton Salnikov et Zinfer R. Ismagilov. « Direct Selective Oxidation of Hydrogen Sulfide : Laboratory, Pilot and Industrial Tests ». Catalysts 11, no 9 (15 septembre 2021) : 1109. http://dx.doi.org/10.3390/catal11091109.

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This article is devoted to scientific and technical aspects of the direct catalytic oxidation of hydrogen sulfide for the production of elemental sulfur. It includes a detailed description of the Claus process as the main reference technology for hydrogen sulfide processing methods. An overview of modern catalytic systems for direct catalytic oxidation technology and known processes is presented. Descriptions of the scientific results of the Institute of Catalysis of the SB RAS in a study of the physical and chemical foundations of the process and the creation of a catalyst for it are included. The Boreskov Institute of Catalysis SB RAS technologies based on fundamental studies and their pilot and industrial testing results are described.
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Latos, Piotr, Anna Wolny et Anna Chrobok. « Supported Ionic Liquid Phase Catalysts Dedicated for Continuous Flow Synthesis ». Materials 16, no 5 (5 mars 2023) : 2106. http://dx.doi.org/10.3390/ma16052106.

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Heterogeneous catalysis, although known for over a century, is constantly improved and plays a key role in solving the present problems in chemical technology. Thanks to the development of modern materials engineering, solid supports for catalytic phases having a highly developed surface are available. Recently, continuous-flow synthesis started to be a key technology in the synthesis of high added value chemicals. These processes are more efficient, sustainable, safer and cheaper to operate. The most promising is the use of heterogeneous catalyst with column-type fixed-bed reactors. The advantages of the use of heterogeneous catalyst in continuous flow reactors are the physical separation of product and catalyst, as well as the reduction in inactivation and loss of the catalyst. However, the state-of-the-art use of heterogeneous catalysts in flow systems compared to homogenous ones remains still open. The lifetime of heterogeneous catalysts remains a significant hurdle to realise sustainable flow synthesis. The goal of this review article was to present a state of knowledge concerning the application of Supported Ionic Liquid Phase (SILP) catalysts dedicated for continuous flow synthesis.
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Kaur, Navjeet, Neha Ahlawat, Pooja Grewal, Pranshu Bhardwaj et Yamini Verma. « Organo or Metal Complex Catalyzed Synthesis of Five-membered Oxygen Heterocycles ». Current Organic Chemistry 23, no 25 (14 janvier 2020) : 2822–47. http://dx.doi.org/10.2174/1385272823666191122111351.

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: The reactions involving the formation of C-O bond using metal as a catalyst have emerged to be one of the most influential reactions for the synthesis of heterocycles in modern organic chemistry. Catalysis by metals offers diverse opportunities to invent new organic reactions with a promising range of selectivities such as chemoselectivity, regioselectivity, diastereoselectivity, and enantioselectivity. The methodologies used earlier for synthesis were less approachable to the organic chemist because of their high cost, highly specified instrumentation and inconvenient methods. For both stereoselective and regioselective formation of five-membered O-containing heterocycles, cyclic reactions that are metal and non-metal-catalyzed have known to be very efficient. The present review article covers the applications of metal and non-metal as a catalyst for the synthesis of five-membered O-containing heterocycles.
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Fiore, Michele, et René Buchet. « Symmetry Breaking of Phospholipids ». Symmetry 12, no 9 (10 septembre 2020) : 1488. http://dx.doi.org/10.3390/sym12091488.

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Either stereo reactants or stereo catalysis from achiral or chiral molecules are a prerequisite to obtain pure enantiomeric lipid derivatives. We reviewed a few plausibly organic syntheses of phospholipids under prebiotic conditions with special attention paid to the starting materials as pro-chiral dihydroxyacetone and dihydroxyacetone phosphate (DHAP), which are the key molecules to break symmetry in phospholipids. The advantages of homochiral membranes compared to those of heterochiral membranes were analysed in terms of specific recognition, optimal functions of enzymes, membrane fluidity and topological packing. All biological membranes contain enantiomerically pure lipids in modern bacteria, eukarya and archaea. The contemporary archaea, comprising of methanogens, halobacteria and thermoacidophiles, are living under extreme conditions reminiscent of primitive environment and may indicate the origin of one ancient evolution path of lipid biosynthesis. The analysis of the known lipid metabolism reveals that all modern cells including archaea synthetize enantiomerically pure lipid precursors from prochiral DHAP. Sn-glycerol-1-phosphate dehydrogenase (G1PDH), usually found in archaea, catalyses the formation of sn-glycerol-1-phosphate (G1P), while sn-glycerol-3-phosphate dehydrogenase (G3PDH) catalyses the formation of sn-glycerol-3-phosphate (G3P) in bacteria and eukarya. The selective enzymatic activity seems to be the main strategy that evolution retained to obtain enantiomerically pure lipids. The occurrence of two genes encoding for G1PDH and G3PDH served to build up an evolutionary tree being the basis of our hypothesis article focusing on the evolution of these two genes. Gene encoding for G3PDH in eukarya may originate from G3PDH gene found in rare archaea indicating that archaea appeared earlier in the evolutionary tree than eukarya. Archaea and bacteria evolved probably separately, due to their distinct respective genes coding for G1PDH and G3PDH. We propose that prochiral DHAP is an essential molecule since it provides a convergent link between G1DPH and G3PDH. The synthesis of enantiopure phospholipids from DHAP appeared probably firstly in the presence of chemical catalysts, before being catalysed by enzymes which were the products of later Darwinian selection. The enzymes were probably selected for their efficient catalytic activities during evolution from large libraries of vesicles containing amino acids, carbohydrates, nucleic acids, lipids, and meteorite components that induced symmetry imbalance.
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Kazemi, Mosstafa, Massoud Ghobadi et Ali Mirzaie. « Cobalt ferrite nanoparticles (CoFe2O4 MNPs) as catalyst and support : magnetically recoverable nanocatalysts in organic synthesis ». Nanotechnology Reviews 7, no 1 (23 février 2018) : 43–68. http://dx.doi.org/10.1515/ntrev-2017-0138.

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AbstractRecovery and reusability of catalysts is an important aspect in modern catalysis research especially in organic synthesis. Compared to the conventional separation, magnetic separation has emerged as a robust, highly efficient, easy and rapid separation technique for products and catalysts. Cobalt ferrite nanoparticles are a well-known material, recognized as CoFe2O4MNPs, and can be used as both catalyst and a versatile support for functionalization of metals, organocatalysts. In recent times, catalysis research has clearly experienced a renaissance in the area of utility of cobalt ferrite (CoFe2O4MNPs) nanocatalysts based on their ability for recovery and reusability; the activity of these CoFe2O4MNPs was investigated in a category of organic reactions. In this review, the fabrication, characterization, and application of cobalt ferrite (CoFe2O4MNPs) nanocatalysts (CF-MNPs) in organic reactions have well summarized.
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Thèses sur le sujet "Catalyse moderne"

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Werner, Emilie. « Catalysis at the origin of life and catalysis today, a 3.8-billion-year jump ». Electronic Thesis or Diss., Strasbourg, 2024. https://publication-theses.unistra.fr/public/theses_doctorat/2024/Werner_Emilie_2024_ED222.pdf.

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La catalyse, permettant une réactivité sélective et accrue, est exploitée aussi bien en chimie de synthèse qu’en biologie. Cette thèse l’abordera à deux temporalités différentes. Dans un premier temps, les processus chimiques aux origines de la vie seront étudiés au travers de deux types de catalyse non enzymatique : la catalyse par les métaux rares et la cocatalyse métal/coenzyme. Cette dernière serait un produit de l’évolution pour s’affranchir d’environnements rares et permettre à la chimie prébiotique de se propager vers des milieux communs. Dans un deuxième temps, la catalyse métallique moderne sera discutée. Une nouvelle variante azotée du réarrangement de Piancatelli sera décrite avec des nucléophiles sulfoximines, permettant d’accéder directement et avec de bons rendements à des 4-sulfoximinocyclopenténones inédites, structures prometteuses pour des applications en chimie médicinale
Catalysis enables selective and enhanced reactivity and is harnessed in both synthetic chemistry and biology. This thesis will discuss this concept at two different time points. Firstly, the chemical processes at the origins of life will be studied through two types of non-enzymatic catalysis: rare metal catalysis and metal/coenzyme cocatalysis. The latter is thought to be a product of evolution to become independent from rare environments and enable prebiotic chemistry to spread to more common media. Secondly, modern metal catalysis will be examined. A new aza-variant of the Piancatelli rearrangement will be described with sulfoximine nucleophiles, giving direct access to unprecedented 4-sulfoximinocyclopentenone scaffolds in good yields. These structures hold promises for applications in drug discovery
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Laher, Romain. « Synthèse de nouvelles molécules odorantes par catalyse à l’or (I) : L’or au service de la parfumerie moderne ». Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4083.

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Ce manuscrit s’intéresse à la synthèse de composés olfactifs intéressants en vue d’une utilisation dans l’industrie de la parfumerie. Un premier chapitre bibliographique met en lumière l’utilisation de métaux de transition comme catalyseurs de réactions servant à la synthèse de composés commercialisés et utilisés dans des parfums. Le travail décrit dans ce manuscrit présente la mise au point et le développement de réactions de cycloisomérisation d’énynes-1,6 et d’additions de nucléophiles sur des substrats acétyléniques par catalyse à l’or (I) dans le but d’obtenir des molécules intéressantes pour l’industrie de la parfumerie. Le second chapitre de ce manuscrit s’intéresse à la synthèse de dérivés de 3-oxabicyclo[4.1.0]-hept-4-ènes. Ces composés ont pu être réalisés avec de très bons rendements à des charges catalytiques faibles, rendant possible l’industrialisation de telles structures. De manière remarquable, l’ensemble des composés synthétisés a présenté un intérêt olfactif, que ce soient les dérivés de départ ou bien les produits de cycloisomérisation. Il a été possible de mettre en évidence une induction de chiralité dans le cadre de la réaction de cycloisomérisation d’énynes-1,6 via l’utilisation de substrats énantiomériquement substitués en position -allylique. Le troisième chapitre met en avant des premiers exemples de réaction tandem de cycloisomérisation / réduction d’alcools acétyléniques ont été effectués conduisant à une nouvelle voie de synthèse de dérivés furaniques et pyraniques. L’emploi de catalyseur d’or permet la formation d’éther d’énol exocyclique puis la réduction de l’insaturation via l’utilisation d’un organosilane. L’ensemble des composés synthétisés évalués présente des notes remarquables permettant d’envisager des substitutions de produits à risque par de nouveaux ingrédients aux propriétés organoleptiques proches
This manuscript is concerned with the synthesis of interesting olfactory compounds for use in the perfume industry. A first bibliographic chapter highlights the use of transition metals as reaction catalysts for the synthesis of compounds marketed and used in perfumes. The work described in this manuscript presents the optimization and development gold (I)-catalyzed cycloisomerization of 1,6-enynes and additions of nucleophiles on acetylenic substrates in order to obtain molecules of interest for the perfume industry. The second chapter of this manuscript deals with the synthesis of 3-oxabicyclo[4.1.0] -hept-4-enes derivatives. These compounds could be produced with very good yields at low catalytic loads, making the industrialization of such structures possible. Remarkably, all of the compounds synthesized were of olfactory interest, whether they were the starting derivatives or the products of cycloisomerization. It has been possible to demonstrate an induction of chirality within the framework of the cycloisomerization reaction of 1,6-enynes via the use of substrates enantiomerically substituted in the -allylic position. The third chapter highlights the first examples of tandem reaction of cycloisomerization / reduction of acetylenic alcohols have been carried out leading to a new route of synthesis of furanic and pyranic derivatives. The use of gold catalyst allows the formation of an exocyclic enol ether followed by the reduction of the unsaturation formed through the use of an organosilane as Et3SiH. All of the synthesized compounds evaluated present remarkable scores allowing to consider substitutions of risky products by new ingredients with similar organoleptic properties
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Lakhdar, Mahjoub. « Application de la reaction d'hydrodesazotation de la pyridine a la caracterisation de l'activite et de la selectivite de catalyseurs sulfures ». Caen, 1987. http://www.theses.fr/1987CAEN2021.

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Isenogle, Melanie R. « Anna Atkins : Catalyst of Modern Photography Through The First Photobook ». Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1522796885194359.

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Dekker, Nicholas John. « The Modern Catalyst : German Influences on the British Stage, 1890-1918 ». Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1180431503.

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WENDLINGER, LAURENT. « Préparation de chlorofluoroalcanes par catalyse hétérogene ». Poitiers, 1989. http://www.theses.fr/1989POIT2252.

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Izquierdo, Colorado Armando. « Reforming of model biogas mixtures at moderate temperatures over Ni-containing catalysts ». Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS147.

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La préoccupation croissante envers les conséquences possiblement dramatiques de l’émission des gaz à effet de serre dans notre atmosphère a eu pour conséquence l’utilisation de ressources renouvelables et d’autres alternatives plus propres pour la génération énergétique, y compris la capture et le recyclage du CO2. Parmi les différents procédés, le reformage à sec utilise deux gaz à effet de serre, le CO2 et le méthane, dans le but de les transformer en H2 et CO, molécules pouvant être utilisées comme plateformes pour la synthèse de carburants et/ou de composés chimiques à haute valeur ajoutée. Dans ce contexte, le biogaz pourrait être utilisé comme une source renouvelable du méthane, qui contient, de plus, une quantité remarquable de CO2, il pourrait être alors transformé en hydrogène et/ou en gaz de synthèse comme une source renouvelable de carbone pour la synthèse de carburants alternatifs. Des catalyseurs à base du nickel ont été envisagés pour les procédés de reformage de méthane et pour son oxydation partielle, ils sont actifs et ont un coût moins élevé que les catalyseurs à base de métaux nobles. Le frittage des particules de Ni et la formation de carbone solide sont des causes de désactivation très importantes. Dans la présente thèse doctorale, de nouveaux catalyseurs à base de Ni sont proposés pour le reformage des mélanges modèles typique d’un biogaz. Dans ce but, des supports différents ont été examinés ainsi l’activation de Ni sur la surface du support. Les résultats ont été analysés en fonction des propriétés physico-chimiques des catalyseurs, évaluées en utilisant différentes techniques de caractérisation comme BET, XRD, CO2-TPD, NH3-TPD et la TEM
The increasing concern about the possible dramatic effects of greenhouse gases emissions to our atmosphere, is leading to propose sustainable alternatives, aiming either capture/storage or capture/utilization of CO2. Among the different technologies, dry reforming of methane has attracted much attention in the past decades because it consumes two of main greenhouse gases (CO2 and CH4) and convert them into useful chemical building blocks. In this context, biogas is another CH4-rich source, containing also non-negligible amounts of CO2, therefore, it can be upgraded into hydrogen and/or synthesis gas, as a renewable carbon source for the synthesis of alternative and carbon-neutral liquid fuels. Nickel-containing catalysts have been considered for methane reforming and its partial oxidation. This is due to its high activity and low cost. However, the sintering and carbon formation, producing catalyst deactivation. Thus, this PhD research focuses on proposing new strategies towards increasing the activity, selectivity and stability of Nickel-containing catalysts for their application in the reforming of biogas model mixtures. These strategies include the use of different supports aiming at increasing their interaction with the active nickel-phase and improving its dispersion and stability. Moreover, different approaches for the deposition of this Ni-phase and its activation have been investigated. The results were correlated with multiple characterizations, such as Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), NH3 and CO2-temperature programmed desorption (CO2-TPD, NH3-TPD) and Transmission electron microscopy (TEM)
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Sharma, Giriraj. « Modeling of selective catalytic reduction (SCR) of nitric oxide with ammonia using four modern catalysts ». Texas A&M University, 2004. http://hdl.handle.net/1969.1/2785.

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In this work, the steady-state performance of zeolite-based Cu-ZSM-5, vanadium based honeycomb monolith catalysts (V), vanadium-titanium based pillared inter layered clay catalyst (V-Ti PLIC) and vanadium-titanium-tungsten-based honeycomb monolith catalysts (V-Ti-W) was investigated in the selective catalytic reduction process (SCR) for NO removal using NH3 in presence of oxygen. The objective is to obtain the expression that would predict the conversion performance of the catalysts for different values of the SCR process parameters, namely temperature, inlet oxygen concentration and inlet ammonia concentration. The NOx emission, its formation and control methods are discussed briefly and then the fundamentals of the SCR process are described. Heat transfer based and chemical kinetics based SCR process models are discussed and widely used rate order based model are reviewed. Based on the experimental data, regression analysis was performed that gives an expression for predicting the SCR rate for the complete temperature range and the rate order with respect to inlet oxygen and ammonia concentration. The average activation energy for the SCR process was calculated and optimum operating conditions were determined for each of the catalyst. The applicable operating range for the catalyst depends on the NO conversion as well as on the ammonia slip and the N2O and NO2 emission. The regression analysis was repeated for the applicable range and an expression was obtained that can be used to estimate the catalyst performance. For the Cu-ZSM-5, the best performance was observed for 400oC, 660 ppm inlet ammonia concentration and 0.1% inlet oxygen concentration. For the V based honeycomb monolith catalyst, the best performance was observed for 300oC, 264 ppm inlet ammonia concentration and 3% inlet oxygen concentration. For the V-Ti based PLIC catalyst, the best performance was observed for 350oC, 330 ppm inlet ammonia concentration and 3% inlet oxygen concentration. For the V-Ti-W based honeycomb monolith catalyst, the best performance was observed for 300oC, 330 ppm inlet ammonia concentration and 3% inlet oxygen concentration. The conversion performance of all of these catalysts is satisfactory for the industrial application. At the operating conditions listed above, the N2O emission is less than 20 ppm and the NO2 emission is less than 10 ppm. The results were validated by comparing the findings with the similar work by other research groups. The mechanism of SCR process is discussed for each of the catalyst. The probable reactions are listed and adsorption and desorption process are studied. The various mechanisms proposed by the researchers are discussed briefly. It is concluded that V-Ti-W and Cu-ZSM-5 catalyst are very promising for SCR of NOx. The expressions can be used to estimate the conversion performance and can be utilized for optimal design and operation. The expressions relate the SCR rate to the input parameters such as temperature and inlet oxygen and ammonia concentration hence by controlling these parameters desired NOx reduction can be achieved with minimal cost and emission.
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Falletta, E. « ¿RE-DISCOVERING¿ AN OLD MATERIAL, POLYANILINE, FOR MODERN APPLICATIONS ». Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/229552.

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The chemical industry of the forthcoming years will be shaped by a number of emerging global megatrends strictly related to the growth and aging of the world population (nine billion people in 2050). This will result in demand of innovative materials able to solve new needs in different fields: health, communication, energy, environmental sustainability, etc. In this diversified context, conducting organic polymers (COPs) are expected to play an important role thanks to their polyhedric properties. Among them, polyaniline is one of the more investigated COPs owing to its peculiar properties which make it a potential substitute of conventional materials in different fields (electronics, fenestration, textile industry, sensors and many others). However, to date many aspects related to its synthesis and application are still open. Scope of the present work is to provide alternative eco-friendly methods to the traditional synthetic routes towards PANI-based materials and enlarge their present applications in view of the novel requirements. This study has been organized in three main sections. In the first section a new green protocol will be present to prepare PANI/metal oxides nanocomposites, innovative materials in the field of EMI shielding. For the first time the double role of magnetic nanoparticles, as catalysts of the reaction and magnetic fillers of the final products, will be illustrated. Conducting/magnetic materials are particularly tempting for their ability to reduce the electromagnetic interferences (EMI) originated by the increasing use of electronic devices and telecommunication equipment. Preliminary results in terms of their microwave absorbing properties will be shown. The possibility to improve the health and quality of life for millions of people worldwide is, in fact, the overall goal of tissue engineering. Nanostructured PANI in form of fibers or wires could find application as novel conductive scaffolds in neuronal or cardiac stimulations. In the second section, the possibility to produce highly pure polyaniline nanofibers by electrospinning technique will be showed. These materials, characterized by high values of conductivity and cytocompatibility, could represent an alternative to traditional solutions for cardiac and neuronal stimulation. Regarding the third section of the work, the amazing piezoresistive properties of PANI, especially in form of film, will be for the first time herein presented. Herein, the extraordinary high GF values of PANI-based films (more than 10 times higher than those of commercial piezoresistors) will be reported. The mechanical monitoring in large and small scale (buildings/touch-technology) needs of highly sensitive stress/strains sensors and PANI-based materials are particularly promising in this sector. All these characteristics contribute to make PANI and its composites innovative materials which could offer new solutions for many challenges of the future.
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Poliukh, К. « Modern state in the research and application of proteolytic enzymes of fungi ». Thesis, National Aviation University, 2021. https://er.nau.edu.ua/handle/NAU/50640.

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1. Braga-Silva L.A., Santos A.L. Aspartic protease inhibitors as potential anti-Candida albicans drugs: impacts on fungal biology, virulence and pathogenesis. Curr Med Chem. 2011. Vol.18 (16). P. 2401-19. 2. Ghosh A.K., Osswald H.L., Prato G. Recent Progress in the developent of HIV-1 protease inhibitors for the treatment of HIV/AIDS. Journal of medicinal chemistry. 2016. Vol. 59 (11). P. 5172–5208. 3. Kim S.Y., Gunasekaran S., Olson N.F. Combined use of chymosin and protease from Cryphonectria parasitica for control of meltability and firmness of cheddar cheese. J Dairy Sci. 2004. Vol. 87(2). P. 274-83. URL: doi: 10.3168/jds.S0022-0302(04)73166-5. 4. Suwannarach N., Kumla J., Sujarit K. et al. Natural bioactive compounds from fungi as potential candidates for protease inhibitors and immunomodulators to apply for coronaviruses. Molecules. 2020. Vol. (25 (8). P.1800. 5. Варбанець Л.Д., Мацелюх О.В. Протеолітичні ферменти мікроорганізмів та методи їх дослідження: монографія. Київ. 2008. 108 с.
Proteolytic enzymes are studied as tools for understanding protein structure and the mechanisms of enzymatic catalysis, or as well as bioactive substances applied in medicine, agriculture and industry. The growing needs of biotechnology, changes in environmental and radiation backgrounds, widespread usage of drugs encourages the search for a new, effective, safe species and strains of fungi which could be the base for new probiotics production and serve in biotransformations of food products.
Протеолітичні ферменти вивчаються як інструменти для розуміння білкової структури та механізмів ферментативного каталізу, або, а також біологічно активних речовин, застосовуваних у медицині, сільському господарстві та промисловості. Зростаючі потреби біотехнології, зміни в екологічних та умовах випромінювання, широке використання наркотиків сприяє пошуку нових, ефективних, безпечних видів та штамів грибів, які можуть бути базою для виробництва нових пробіотиків та служать у біотрансформаціях харчових продуктів.
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Livres sur le sujet "Catalyse moderne"

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R, Moser William, dir. Advanced catalysts and nanostructured materials : Modern synthetic methods. San Diego : Academic Press, 1996.

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van Santen, Rutger A., dir. Modern Heterogeneous Catalysis. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2017. http://dx.doi.org/10.1002/9783527810253.

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Hashmi, A. Stephen K., et F. Dean Toste, dir. Modern Gold Catalyzed Synthesis. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2012. http://dx.doi.org/10.1002/9783527646869.

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Andrew, Evans P., dir. Modern rhodium-catalyzed organic reactions. Weinheim : Wiley-VCH, 2005.

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Chorkendorff, I. Concepts of modern catalysis and kinetics. Weinheim : Wiley-VCH, 2004.

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Chorkendorff, I. Concepts of modern catalysis and kinetics. Weinheim [Germany] : Wiley-VCH, 2003.

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Chorkendorff, I. Concepts of modern catalysis and kinetics. 2e éd. Weinheim : Wiley-VCH, 2007.

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University of Virginia. School of Architecture. Catalyst : 2012-2013 UVa. Sous la direction de Abbasy-Asbagh Ghazal editor, Hora Rebecca, Metcalf Ryan et Pinyan Matthew. New York, NY : Actar D, 2013.

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Mizuno, Noritaka. Modern heterogeneous oxidation catalysis : Design, reactions and characterization. Weinheim : Wiley-VCH, 2009.

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Fessner, W. D. Modern biocatalysis : Stereoselective and environmentally friendly reactions. Weinheim : Wiley-VCH, 2009.

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Chapitres de livres sur le sujet "Catalyse moderne"

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Deng, Jiayao, Xiao Hu, Gnauizhi Xu, Zhanfeng Deng, Lan Yang, Ding Chen, Ming Zhou et Boyuan Tian. « The Preparation of Iridium-Based Catalyst with Different Melting Point-Metal Nitrate and Its OER Performance in Acid Media ». Dans Proceedings of the 10th Hydrogen Technology Convention, Volume 1, 61–68. Singapore : Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-8631-6_6.

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AbstractOxygen evolution reaction (OER) is the main factor limiting the large-scale development of proton-exchange membrane (PEM) hydrogen production. It is urgent to develop catalysts with excellent OER catalytic performance and stability. Herein, several Iridium-based catalysts were prepared by simple mixing and calcination, the OER properties of catalysts with different melting points of nitrates as calcinating additives were investigated. The RbNO3 treated catalyst displayed a low overpotential(η) of 297.6 mV versus RHE, which is lower than the catalyst calcinated without nitrate (323.8 mV vs. RHE). Moreover, the RbNO3 treated catalyst displayed good acid stability over 20 h Chronopotentiometric test. The high OER catalytic activity and stability of RbNO3 treated catalyst may be attribute to the smaller nanoparticle morphology, pure IrO2 structure and high electrochemical surface area (ECSA), which increase the number of active sites and the intrinsic catalytic activity. This work indicated that the catalyst with excellent OER performance can be obtained by selecting nitrate with moderate melting point as the calcinating additive. Nitrates (like RbNO3) treated catalyst with excellent catalytic activity and stability has good application prospect in hydrogen production of PEM water splitting.
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Osawa, Tsutomu. « Heterogeneous Catalysis ». Dans Modern Organonickel Chemistry, 273–305. Weinheim, FRG : Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527604847.ch10.

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Park, Joo-Il, Isao Mochida, Abdulazeem M. J. Marafi et Adel Al-Mutairi. « Modern Approaches to Hydrotreating Catalysis ». Dans Springer Handbook of Petroleum Technology, 675–712. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-49347-3_21.

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Corma, Avelino, et Pedro Serna. « Gold-Catalyzed Reduction Reactions ». Dans Modern Gold Catalyzed Synthesis, 27–54. Weinheim, Germany : Wiley-VCH Verlag GmbH & Co. KGaA, 2012. http://dx.doi.org/10.1002/9783527646869.ch2.

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Tributsch, H. « Photoelectrolysis and Photoelectrochemical Catalysis ». Dans Modern Aspects of Electrochemistry, 303–55. Boston, MA : Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-2133-0_4.

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Takahashi, Tamotsu, et Ken-ichiro Kanno. « Nickel-Catalyzed Cross-Coupling Reactions ». Dans Modern Organonickel Chemistry, 41–55. Weinheim, FRG : Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527604847.ch2.

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Mori, Miwako, et Masanori Takimoto. « Nickel-Mediated and -Catalyzed Carboxylation ». Dans Modern Organonickel Chemistry, 205–23. Weinheim, FRG : Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527604847.ch7.

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Kasey, Christian, et Gavin J. Williams. « Chapter 8. Customizing Transcription-factor Biosensors for Modern Biotechnology ». Dans Catalysis Series, 203–33. Cambridge : Royal Society of Chemistry, 2018. http://dx.doi.org/10.1039/9781788010450-00203.

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Chi, Yongxiang, Wenjun Tang et Xumu Zhang. « Rhodium-Catalyzed Asymmetric Hydrogenation ». Dans Modern Rhodium-Catalyzed Organic Reactions, 1–31. Weinheim, FRG : Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527604693.ch1.

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Sinou, Denis. « Metal Catalysis in Water ». Dans Modern Solvents in Organic Synthesis, 41–59. Berlin, Heidelberg : Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/3-540-48664-x_2.

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Actes de conférences sur le sujet "Catalyse moderne"

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Manrique Carrera, Arturo, Jeevan Jayasuriya et Torsten Fransson. « Staged Lean Catalytic Combustion of Gasified Biomass for Gas Turbine Applications : An Experimental Approach to Investigate Performance of Catalysts ». Dans ASME Turbo Expo 2013 : Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95339.

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Emission demands for gas turbine utilization will become more stringent in the coming years. Currently different techniques are used to reach low levels of NOx emissions. One possible solution is the Staged Lean Catalytic Combustion. In this concept a catalysts arrangement is used to generate high temperature combustion gases. The high temperature gases could be used to feed a second combustion stage in which more fuel is injected. In this work a series of experiments were performed at the Catalytic Combustion High Pressure Test Facility at the Royal Institute of Technology (KTH) in Sweden. The fuel used was a simulated gasified biomass and the catalytic combustor consisted of an arrangement of different catalysts, e.g. bimetallic, hexaaluminates, and perovskites catalysts. These were used as, ignition catalyst, medium temperature catalyst and high temperature catalyst respectively. The tests were performed between 5 and 13.5 bar, and the overall conversion varied between 60% and 70% and the temperature of flue gases could reach 750°C and contains high level of oxygen. The determining factor to control the exit gas temperature was the richness of the mixture (λ value). On the other hand, the increased pressure had a moderate negative effect in the overall fuel conversion. This effect is stronger at leaner mixtures compared to richer ones. Moreover, λ value and also pressure affected the temperature distribution along the reactor. The utilization of a lean catalytic combustion approach makes possible the use of a post catalytic combustion. In this region additional fuel is injected to fully burn the exiting gases and increase the exit temperature to the desired levels. This staged lean catalytic combustion approach could resemble moderate levels exhaust gas recirculation techniques and/or high air temperature combustion and it is also briefly examined in the present work.
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Berahim, Nor Hafizah, et Akbar Abu Seman. « CO2 Utilization : Converting Waste into Valuable Products ». Dans SPE Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210729-ms.

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Abstract Carbon dioxide capture, utilization, and storage (CCUS), which includes conversion to valuable products, is a complex modern issue with many perspectives. In recent years, the idea of using carbon dioxide (CO2) as a feedstock for synthetic applications in the chemical and fuel sectors via reduction reactions has piqued interest. If the hydrogen is created using a renewable energy source, catalytic CO2 hydrogenation is the most viable and appealing alternative among the existing CO2-recycling solutions. CO2 hydrogenation has many chemical paths depending on the catalyst, and multiple value-added hydrocarbons can be generated. This research looks into a catalyst development for converting high CO2 gas field into methane and alcohols. The study focused on catalytic conversion of CO2 to methane over Ru based catalyst while in the case of alcohols using Cu based catalyst. Both catalysts were synthesized via impregnation techniques where the aqueous precursors’ solution were impregnated on the oxide supports, stirred, filtered and washed. The samples were then dried, ground and calcined. The synthesized catalysts were characterized using various analytical techniques (e.g., TPR, FESEM, N2 adsorption-desorption, XRD) for their physicochemical properties. The catalytic performance in CO2 hydrogenation was performed using a fixed bed reactor at various factors such as temperature, pressure, feed gas ratio and space velocity. The experimental findings indicate that conversion of CO2 to methane over Ru based catalyst resulted in >84% CO2 conversion with 99% methane selectivity in the range of temperature 280 – 320 °C and at atmospheric pressure. In the case of hydrogenation of CO2 to alcohols, the catalytic performance of Cu based catalyst exhibited CO2 conversion of >11% and selectivity towards alcohols, C1 and C2, both at 4% with reaction temperature of 250 °C and pressure 30 bar. These findings revealed that methane could easily be formed from CO2 as compared to alcohol. However, both technology conversions are dependent on the catalyst selection and its’ activity. Process parameters need to be optimized to maximize targeted product formation and suppress the side products.
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Patel, Sanjay, et K. K. Pant. « Hydrogen Production for PEM Fuel Cells via Oxidative Steam Reforming of Methanol Using Cu-Al Catalysts Modified With Ce and Cr ». Dans ASME 2006 4th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2006. http://dx.doi.org/10.1115/fuelcell2006-97209.

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The performance of Cu-Ce-Al-oxide and Cu-Cr-Al-oxide catalysts of varying compositions prepared by co-precipitation method was evaluated for the PEM fuel cell grade hydrogen production via oxidative steam reforming of methanol (OSRM). The limitations of partial oxidation and steam reforming of methanol for the hydrogen production for PEM fuel cell could be overcome using OSRM and can be performed auto-thermally with idealized reaction stoichiomatry. Catalysts surface area and pore volume were determined using N2 adsorption-desorption method. The final elemental compositions were determined using atomic absorption spectroscopy. Crystalline phases of catalyst samples were determined by X-ray diffraction (XRD) technique. Temperature programmed reduction (TPR) demonstrated that the incorporation of Ce improved the copper reducibility significantly compared to Cr promoter. The OSRM was carried out in a fixed bed catalytic reactor. Reaction temperature, contact-time (W/F) and oxygen to methanol (O/M) molar ratio varied from 200–300°C, 3–21 kgcat s mol−1 and 0–0.5 respectively. The steam to methanol (S/M) molar ratio = 1.4 and pressure = 1 atm were kept constant. Catalyst Cu-Ce-Al:30-10-60 exhibited 100% methanol conversion and 152 mmol s−1 kgcat−1 hydrogen production rate at 300°C with carbon monoxide formation as low as 1300 ppm, which reduces the load on preferential oxidation of CO to CO2 (PROX) significantly before feeding the hydrogen rich stream to the PEM fuel cell as a feed. The higher catalytic performance of Ce containing catalysts was attributed to the improved Cu reducibility, higher surface area, and better copper dispersion. Reaction parameters were optimized in order to maximize the hydrogen production and to keep the CO formation as low as possible. The time-on-stream stability test showed that the Cu-Ce-Al-oxide catalysts subjected to a moderate deactivation compared to Cu-Cr-Al-oxide catalysts. The amount of carbon deposited onto the catalysts was determined using TG/DTA thermogravimetric analyzer. C1s spectra were obtained by surface analysis of post reaction catalysts using X-ray photoelectron spectroscopy (XPS) to investigate the nature of coke deposited.
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Нурмахаматов, Герман Владимирович, et Владислав Сергеевич Хрипко. « IMPROVING THE ENERGY EFFICIENCY OF THE REFINING PROCESS BY THE EXAMPLE OF THE ISOMERIZATION PROCESS ». Dans Наука, общество, производство и промышленность : актуальные проблемы и перспективы : сборник статей международной научной конференции (Омск, Апрель 2023). Crossref, 2023. http://dx.doi.org/10.37539/230407.2023.66.59.002.

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Повышение энергоэффективности процесса нефтепереработки является одним из важных процессов, используемых современными нефтеперерабатывающими заводами для катализа твердых кислот из-за ограниченного содержания бензола, ароматических соединений и олефинов в бензине. Целью данной статьи является изучение влияния различных катализаторов на изомеризацию светлых нефтепродуктов. Improving the energy efficiency of the refining process is one of the important processes used by modern refineries for the catalysis of solid acids due to the limited content of benzene, aromatic compounds and olefins in gasoline. The purpose of this article is to study the effect of various catalysts on the isomerization of light petroleum products.
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Olimov, Bobir, et Vohid Akhmedov. « THE EFFECT OF REACTION DURATION AND CATALYST ON THE SYNTHESIS OF ARYLVINYL ESTERS ». Dans MODALITĂȚI CONCEPTUALE DE DEZVOLTARE A ȘTIINȚEI MODERNE. European Scientific Platform, 2020. http://dx.doi.org/10.36074/20.11.2020.v2.07.

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Sappok, Alexander G., et Victor W. Wong. « Comparative Particulate Trap Performance Using Fischer-Tropsch and Conventional Diesel Fuels in a Modern CI Engine ». Dans ASME 2006 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ices2006-1345.

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Increasingly stringent emissions regulations aimed at drastically reducing particulate emissions from diesel engines pose one of the greatest challenges to diesel engine development today. Furthermore, engine manufacturers are finding it more and more difficult to comply with these new regulations through in-cylinder optimization alone. As a result, exhaust after-treatment systems, namely diesel particulate traps, present additional means for meeting these strict requirements. A previous study demonstrated the potential for diesel particulate emissions reduction using neat Fischer-Tropsch (F-T) fuel and blends. The absence of sulfur in F-T fuels permits the use of more aggressively catalyzed traps, as sulfur poisoning is not an issue. Furthermore, the reduced particulate emissions of F-T fuels leads to increased time between trap regenerations, which in conjunction with advanced catalyst formulations reducing the temperatures required to initiate regeneration, may provide substantial improvements in trap durability and performance. However, the deposition of particulates from F-T fuels on the trap substrates and loading and regeneration of the trap with F-T particulates and F-T fuel have not been adequately addressed. In this study a 2002, six-cylinder, 5.9 liter, Cummins ISB 300 diesel engine, outfitted with a fully instrumented particulate trap, was subjected to a subset of the Euro III 13-mode test cycle under steady-state operating conditions. In order to investigate the fundamental fuel effects on particulate trap loading characteristics, un-catalyzed Cordierite substrates were loaded with particulates generated from neat F-T diesel and a low sulfur diesel (LSD). Trap temperature, pressure drop, particulate emissions, and gaseous exhaust composition were monitored before and after the trap. The use of F-T fuel significantly extended the trapping period and reduced the regeneration frequency as compared to the LSD. Based on the differences in emissions and fuel composition, explanations for the observed differences in the trap performance were developed.
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Muravyova, E. A., et R. F. Gabitov. « Economic Features to Optimize the Catalyst Calcinations Process ». Dans 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon). IEEE, 2018. http://dx.doi.org/10.1109/fareastcon.2018.8602535.

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Simijonović, Dušica, Edina Avdović, Žiko Milanović, Dejan Milenković et Zoran Marković. « Green synthesis of chromeno-pyrimidine derivatives – Part I ». Dans 2nd International Conference on Chemo and Bioinformatics. Institute for Information Technologies, University of Kragujevac, 2023. http://dx.doi.org/10.46793/iccbi23.686s.

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Two different chromeno-pyrimidine derivatives were synthetized in the ionic liquid catalyzed reaction of barbituric acid and substituted salicylaldehydes. The product 5-(7-bromo-2,4-dioxo-1,3,4,5-tetrahydro-2H-chromeno[2,3-d]pyrimidin-5-yl)pyrimidine-2,4,6(1H,3H,5H)-tri-one (CP-1) was obtained in the reaction of barbiruric acid and 5-bromo-2-hydroxybenzaldehyde. The second new product 8,9-dihydroxy-2H-chromeno[2,3-d]pyrimidine-2,4(3H)-dione (CP-2) was yielded in the reaction between barbituric acid and 2,3,4-trihydroxybenzaldehyde. These products were isolated in moderate to good yield after 3h reflux in mixture of water: ethanol (1:1v/v) and in presence 20 mol% of catalyst – diethanolammonium chloroacetate. The structure of obtained products was confirmed using 1H NMR, 13C NMR, and IR spectroscopy methods.
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Zheng, Ming, David K. Irick et Jeffrey Hodgson. « Stabilizing Excessive EGR With an Oxidation Catalyst on a Modern Diesel Engine ». Dans ASME 2002 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/ices2002-455.

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For diesel engines (CIDI) the excessive use of exhaust gas recirculation (EGR) can reduce in-cylinder oxides of nitrogen (NOx) generation dramatically, but engine operation can also approach zones with high instabilities, usually accompanied with high cycle-to-cycle variations and deteriorated emissions of total hydrocarbon (THC), carbon monoxide (CO), and soot. A new approach has been proposed and tested to eliminate the influences of recycled combustibles on such instabilities, by applying an oxidation catalyst in the high-pressure EGR loop of a turbocharged diesel engine. The testing was directed to identifying the thresholds of stable operation at high rates of EGR without causing cycle-to-cycle variations associated with untreated recycled combustibles. The elimination of recycled combustibles using the oxidation catalyst showed significant influences on stabilizing the cyclic variations, so that the EGR applicable limits are effectively extended. The attainability of low NOx emissions with the catalytically oxidized EGR is also evaluated.
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Fan, Dinghui, Li Yin et Zuyu Liu. « Preparation and activity of perovskite-type catalyst LaCo1−2xMnxCuxO3/γ-Al2O3 ». Dans International Conference on Modern Engineering Soultions for the Industry. Southampton, UK : WIT Press, 2014. http://dx.doi.org/10.2495/mesi141402.

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Rapports d'organisations sur le sujet "Catalyse moderne"

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Kang, Grace, Sifat Muin, Jorge Archbold, Bitanoosh Woods et Khalid Mosalam. Expected Earthquake Performance of Buildings Designed to the California Building Code. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, juillet 2019. http://dx.doi.org/10.55461/lotg8562.

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The brochure explains the intent of the California Building Code, the expected performance of code-compliant new buildings when they are subjected to moderate and large earthquakes, possible consequences to residents, businesses, and communities, and initial proactive actions that can be taken. “This publication combines information from the earthquake engineering community as well as policy and community officials, and it incorporates input from SSC’s commissioners and staff, whose valuable feedback reflected their diverse range of expertise and experience,” said Grace Kang, PEER Director of Communications. “The brochure is an educational tool intended to raise public awareness and provide basic information for decision-makers. It can be used to initiate and catalyze discussion.”
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Hotsur, Oksana. FROM THE ECONOMIC CRISIS TO COVID-19 : FEATURES OF THE DEVELOPMENT OF THE PRINT MEDIA MARKET OF UKRAINE. Ivan Franko National University of Lviv, février 2022. http://dx.doi.org/10.30970/vjo.2022.51.11396.

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The study analyzes the traditional media during 2013-2021 and draws attention to a number of factors, factors of economic and global nature in the historical context, which affect the general state of the media market in Ukraine. The main goal is to outline the peculiarities of the development of the print media market in modern conditions and challenges. The study uses socio-communicative and axiological approaches, methods of content analysis, synthesis and general are the main methods that were used in the research process. In addition to catalysts for abrupt changes in the print media market of Ukraine, factors have been identified that significantly affect the development trends of the general media market: digitalization, destruction of logistics, periodicals, outflow of advertisers from traditional media (television, radio, newspapers and magazines). There are already forecasts that due to the increase in the price of paper on the world market there will be an increase in prices for printed products by 40%), the lack of a culture of consumption of subscription information, as there is a free alternative (social networks, search engines). Results/findings and conclusions of my research: a set of three crisis periods, as a result of which the factors identified in the study are the main characteristics of the development of the modern print media market in Ukraine. The print media market, due to the global situation through COVID-19, is going through difficult times. In fact, the prospect for further scientific research may be the study of the financial component of the Ukrainian media market in the context of general world trends.
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Kanner, Joseph, Dennis Miller, Ido Bartov, John Kinsella et Stella Harel. The Effect of Dietary Iron Level on Lipid Peroxidation of Muscle Food. United States Department of Agriculture, janvier 1995. http://dx.doi.org/10.32747/1995.7604282.bard.

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Biological oxidations are almost exclusively metal ion-promoted reactions and in ths respect iron, being the most abundant, is the commonly involved. The effect of dietary iron levels on pork, turkey and chick muscle lipid peroxidation and various other related compounds were evaluated. Crossbred feeder pigs were fed to market weight on corn-soy rations containing either 62, 131 or 209 ppm iron. After slaughter, the muscles were dissected, cooked and stored at 4°C. Heavily fortifying swine rations with iron (>200 ppm) increase nn-heme iron (NHI), thiobarbituric acid reactive substances (TBARS), and decrease a-tocopherol in cooked stored pork but did not increase warmed-over aroma (WOA). NHI and TBARS were higher in cooked pork from pigs fed high-iron diets. Liver iron correlated with muscle iron. TBARS were strongly related with WOA. The role of dietary vitamin E and ascorbic acid on Fe-induced in vivo lipid peroxidation in swine was also evaluated. Moderate elevation in iron stores had a marked effect on oxidative stress, especially as indicated by liver TBARS. Supplemental vitamin E, and to a lesser extent vitamin C, protect against this oxidative stress. Unsupplementation of Fe in the regular diet of turkeys did not affect body weight, blood hemoglobin level, or iron pool in the liver or muscle. The reason being that it contained "natural" ~120 mg Fe/kg feed, and this amount is high enough to keep constant the pool of iron in the body, liver or muscle tissues. Only Fe-supplementation with high amounts of Fe (500 ppm) significantly increased turkey blood hemoglobin and total iron in the liver, in 1 out of 3 experiments, but only slightly affects iron pool in the muscles. It seems that the liver accumulates very high concentations of iron and significantly regulates iron concentration in skeletal muscles. For this reason, it was very difficult to decrease muscle stability in turkeys through a diet containing high levels of Fe-supplementation. It was shown that the significant increase in the amount of iron (total and "free") in the muscle by injections with Fe-dextran accelerated its lipid peroxidation rate and decreased its a-tocopherol concentration. The level and metabolism of iron in the muscles affects the intensity of in vivo lipid peroxidation. This process was found to ifluence the turnover and accumulation of a-tocopherol in turkey and chick muscles. Treatments which could significantly decrease the amount and metabolism of iron pool in muscle tissues (or other organs) may affect the rate of lipid peroxidation and the turnover of a-tocopherol. Several defense enzymes were determined and found in the turkey muscle, such as superoxide dismutase, catalase, and glutathione peroxidase. Glutathione peroxidase was more active in muscles with a high trend of lipid peroxidation, lmore so in drumsticks than in breast muscles, or muscles with a low a-tocopherol content. The activity of glutathione peroxidase increased several fold in muscle stored at 4°C. Our work demonstrated that it will be much more practical to increase the stability of muscle tissues in swine, turkeys and chickens during storage and processing by increasing the amount of vitamin E in the diet than by withdrawing iron supplementation.
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Hochman, Ayala, Thomas Nash III et Pamela Padgett. Physiological and Biochemical Characterization of the Effects of Oxidant Air Pollutants, Ozone and Gas-phase Nitric Acid, on Plants and Lichens for their Use as Early Warning Biomonitors of these Air Pollutants. United States Department of Agriculture, janvier 2011. http://dx.doi.org/10.32747/2011.7697115.bard.

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Introduction. Ozone and related oxidants are regarded as the most important phytotoxic air pollutant in many parts of the western world. A previously unrecognized component of smog, nitric acid, may have even greater deleterious effects on plants either by itself or by augmenting ozone injury. The effects of ozone on plants are well characterized with respect to structural and physiological changes, but very little is known about the biochemical changes in plants and lichens exposed to ozone and/or HNO3. Objectives.To compare and contrast the responses of crop plants and lichens to dry deposition of HNO3 and O3., separately, and combined in order to assess our working hypothesis that lichens respond to air pollution faster than plants. Lichens are most suitable for use as biomonitors because they offer a live-organism-based system that does not require maintenance and can be attached to any site, without the need for man-made technical support systems. Original Immediate aims To expose the tobacco (Nicotiana tabacum L.) cultivar Bel-W3 that is ozone supersensitive and the ozone sensitive red kidney bean (Phaseolusvulgaris) and the lichen Ramalinamenziesii to controlled HNO3 and O3 fumigations and combined and to follow the resulting structural, physiological and biochemical changes, with special reference to reactive oxygen species related parameters. Revised. Due to technical problems and time limitations we studied the lichen Ramalinamenziesii and two cultivar of tobacco: Bel-W3 that is ozone supersensitive and a resistant cultivar, which were exposed to HNO3 and O3 alone (not combined). Methodology. Plants and lichens were exposed in fumigation experiments to HNO3 and O3, in constantly stirred tank reactors and the resulting structural, physiological and biochemical changes were analyzed. Results. Lichens. Exposure of Ramalinamenziesiito HNO3 resulted in cell membrane damage that was evident by 14 days and continues to worsen by 28 days. Chlorophyll, photosynthesis and respiration all declined significantly in HNO3 treatments, with the toxic effects increasing with dosage. In contrast, O3 fumigations of R. menziesii showed no significant negative effects with no differences in the above response variables between high, moderate and low levels of fumigations. There was a gradual decrease in catalase activity with increased levels of HNO3. The activity of glutathione reductase dropped to 20% in thalli exposed to low HNO3 but increased with its increase. Glucose 6-phosphate dehydrogenase activity increase by 20% with low levels of the pollutants but decreased with its increase. Tobacco. After 3 weeks of exposure of the sensitive tobacco cultivar to ozone there were visible symptoms of toxicity, but no danmage was evident in the tolerant cultivar. Neither cultivar showed any visible symptoms after exposure to HNO3.In tobacco fumigated with O3, there was a significant decrease in maximum photosynthetic CO2 assimilation and stomatal conductance at high levels of the pollutant, while changes in mesophyll conductance were not significant. However, under HNO3 fumigation there was a significant increase in mesophyll conductance at low and high HNO3 levels while changes in maximum photosynthetic CO2 assimilation and stomatal conductance were not significant. We could not detect any activity of the antioxidant enzymes in the fumigated tobacco leaves. This is in spite of the fact that we were able to assay the enzymes in tobacco leaves grown in Israel. Conclusions. This project generated novel data, and potentially applicable to agriculture, on the differential response of lichens and tobacco to HNO3 and O3 pollutants. However, due to experimental problems and time limitation discussed in the body of the report, our data do not justify yet application for a full, 4-year grant. We hope that in the future we shall conduct more experiments related to our objectives, which will serve as a basis for a larger scale project to explore the possibility of using lichens and/or plants for biomonitoring of ozone and nitric acid air pollution.
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