Relevant bibliographies by topics / Catalyse aqueuse

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Catalyse aqueuse'

Author: Grafiati
Published: 4 June 2021
Last updated: 8 February 2022

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Journal articles on the topic "Catalyse aqueuse"

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Khan, Mohammad Niyaz, and Ibrahim Isah Fagge. "Kinetics and Mechanism of Cationic Micelle/Flexible Nanoparticle Catalysis: A Review." Progress in Reaction Kinetics and Mechanism 43, no. 1 (March 2018): 1–20. http://dx.doi.org/10.3184/146867818x15066862094905.

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The aqueous surfactant (Surf) solution at [Surf] > cmc (critical micelle concentration) contains flexible micelles/nanoparticles. These particles form a pseudophase of different shapes and sizes where the medium polarity decreases as the distance increases from the exterior region of the interface of the Surf/H2O particle towards its furthest interior region. Flexible nanoparticles (FNs) catalyse a variety of chemical and biochemical reactions. FN catalysis involves both positive catalysis ( i.e. rate increase) and negative catalysis ( i.e. rate decrease). This article describes the mechanistic details of these catalyses at the molecular level, which reveals the molecular origin of these catalyses. Effects of inert counterionic salts (MX) on the rates of bimolecular reactions (with one of the reactants as reactive counterion) in the presence of ionic FNs/micelles may result in either positive or negative catalysis. The kinetics of cationic FN (Surf/MX/H2O)-catalysed bimolecular reactions (with nonionic and anionic reactants) provide kinetic parameters which can be used to determine an ion exchange constant or the ratio of the binding constants of counterions.
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Lukey, CA, MA Long, and JL Garnett. "Aromatic Hydrogen Isotope Exchange Reactions Catalyzed by Iridium Complexes in Aqueous Solution." Australian Journal of Chemistry 48, no. 1 (1995): 79. http://dx.doi.org/10.1071/ch9950079.

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Sodium hexachloroiridate (III) and sodium hexachloroiridate (IV) have been used as homogeneous catalysts for hydrogen isotope exchange between benzenoid compounds and water. The ideal solvent consisted of 50 mole % acetic acid/water, and the optimum temperature was found to be 160°C. Under these conditions the rate of incorporation of deuterium into benzene was significant (typically 15% D in 6 h), and reduction to iridium metal was minimized. The active catalytic species was identified as a solvated iridium(III) species, which is also postulated to be the active catalyst in solutions containing hexachloroiridate (IV). The kinetics of exchange in benzene catalysed by sodium hexachloroiridate (III) were elucidated, and found to be more complex than for the corresponding sodium tetrachloroplatinate (II) catalysed exchange, in that a two-term rate dependence was found for catalyst concentration and the reaction was inversely dependent on hydrogen ion concentration. The reaction was found to be independent of chloride ion concentration, this confirming that the active catalyst is a solvated species. Isotopic labelling in all compounds was confined to the aromatic ring, and most substituted benzenes exhibited deactivation of the ortho positions, indicating that a dissociative π-complex exchange mechanism was operating. This was confirmed by exchange into naphthalene, where it was found that labelling was predominantly in the β position. Facile exchange into nitrobenzene provided good evidence of homogeneous catalysis, and not catalysis by precipitated metal.
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Salvio, Riccardo, Roberta Cacciapaglia, Luigi Mandolini, Francesco Sansone, and Alessandro Casnati. "Diguanidinocalix[4]arenes as effective and selective catalysts of the cleavage of diribonucleoside monophosphates." RSC Adv. 4, no. 65 (2014): 34412–16. http://dx.doi.org/10.1039/c4ra05751a.

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Upper rim diguanidino-cone-calix[4]arenes catalyze the hydrolytic cleavage of diribonucleoside monophosphates in aqueous DMSO with good substrate selectivity and rate accelerations approaching 105-fold in the most favourable substrate-catalyst combinations.
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Zhuang, Huimin, Bili Chen, Wenjin Cai, Yanyan Xi, Tianxu Ye, Chuangye Wang, and Xufeng Lin. "UiO-66-supported Fe catalyst: a vapour deposition preparation method and its superior catalytic performance for removal of organic pollutants in water." Royal Society Open Science 6, no. 4 (April 2019): 182047. http://dx.doi.org/10.1098/rsos.182047.

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A vapour deposition (VD) method was established for preparation of the UiO-66-supported Fe (Fe/UiO-66) catalyst, which provided the first case of the metal-organic framework (MOF)-supported Fe catalyst prepared by using the vapour-based method. The Fe loading was around 7.0–8.5 wt% under the present preparation conditions. The crystal structure of UiO-66 was not obviously influenced by the Fe loading, while the surface area significantly decreased, implicating most of the Fe components resided in the pores on UiO-66. The results for the methyl orange (MO) removal tests showed that MO in aqueous solution can be removed by UiO-66 by adsorption, and in contrast, it can be oxidized by H 2 O 2 with the catalysis of Fe/UiO-66. Further catalytic tests showed that Fe/UiO-66 was rather effective to catalyse the oxidation of benzene derivatives like aniline in water in terms of chemical oxygen demand (COD) removal efficiency. The catalytic test results for Fe/UiO-66 were compared to those of Fe/Al 2 O 3 with the same Fe loading and to the catalysts reported in the literature. This paper provides a general strategy for VD preparation of MOF-supported Fe catalyst on the one hand, and new catalysts for removing organic pollutants from water, on the other hand.
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Wang, Changlong, Lionel Salmon, Roberto Ciganda, Luis Yate, Sergio Moya, Jaime Ruiz, and Didier Astruc. "An efficient parts-per-million α-Fe2O3 nanocluster/graphene oxide catalyst for Suzuki–Miyaura coupling reactions and 4-nitrophenol reduction in aqueous solution." Chemical Communications 53, no. 3 (2017): 644–46. http://dx.doi.org/10.1039/c6cc08401j.

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α-Fe2O3 nanoclusters supported onto a graphene oxide catalyst are shown for the first time to catalyze Suzuki–Miyaura coupling and 4-nitrophenol reduction in aqueous solution with only parts-per-million loading.
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Voitko, K. V., O. M. Bakalinska, Yu V. Goshovska, Yu I. Sementsov, and M. T. Kartel. "Catalase-like properties of multilayer graphene oxides and their modified forms." Surface 12(27) (December 30, 2020): 251–62. http://dx.doi.org/10.15407/surface.2020.12.251.

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The catalytic system, that mimets catalase enzyme such as “multilayer graphene oxide /peroxide molecule” in aqueous media was investigated. The main factors that influence on catalyst’s effectiveness were determining. The catalytic activity of as-synthesized multilayered graphene oxides, and their modified forms (oxidized and nitrogen doped) were investigated in the decomposition of hydrogen peroxides at room temperature and physiological pHs by measuring the volume of released gases. A phosphate buffer with a pH of 5 to 8 was chosen as the reaction medium. The original and modified samples were characterized using XPS, TPD-MS, Boehm titration analyses. The effect of surface chemistry on the catalytic reaction proceeding has been studied. It was found that catalysis on the graphene plane is determined by the presence of heteroatoms in their structure. The catalytic process takes place in the kinetic zone over the entire accessible surface of the samples. The active sites of the catalysts contain a large amount of both nitrogen and oxygen-containing functional groups. In addition, the surface of graphene oxide is hydrophilic, which enhances the catalytic reaction in an aqueous medium. It has been established that the rate of hydrogen peroxide decomposition by reduced graphene oxide samples is lower than for samples modified with oxygen and nitrogen. The catalase-like activity of graphene increases in alkaline pH up to 7.8. Studies have shown that samples of multilayer graphenes with a high content of functional groups can be an alternative to the catalase enzyme as a catalyst for the decomposition of hydrogen peroxide in physiological solutions.
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Pradhan, Subhashis, Subhadip Dutta, and Rohith P. John. "A coordination driven self-assembled Pd6L8 nanoball catalyses copper and phosphine-free Sonogashira coupling reaction in both homogeneous and heterogeneous formats." New Journal of Chemistry 40, no. 8 (2016): 7140–47. http://dx.doi.org/10.1039/c5nj03658e.

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A self-assembled Pd6L8 nanocage catalysed copper free Sonogashira reaction under mild and aerobic conditions, at 100 ppm catalyst loading in aqueous medium in the homogeneous phase, and at 500 ppm in the heterogeneous phase.
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Khosravi, Kaveh, Mojgan Zendehdel, Shirin Naserifar, Fatemeh Tavakoli, Kobra Khalaji, and Atefeh Asgari. "Heteropoly acid/NaY zeolite as a reusable solid catalyst for highly efficient synthesis of gem-dihydroperoxides and 1,2,4,5-tetraoxanes." Journal of Chemical Research 40, no. 12 (December 2016): 744–49. http://dx.doi.org/10.3184/174751916x14792244600532.

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gem-Dihydroperoxides and 1,2,4,5-tetraoxanes were synthesised from aldehydes and ketones catalysed by heteropoly acid/NaY zeolite (HPA/NaY) as a new, effective and reusable solid catalyst using 30% aqueous hydrogen peroxide at room temperature. The reactions proceeded with high rates and excellent yields.
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Wang, Hui, Ambra Maria Fiore, Christophe Fliedel, Eric Manoury, Karine Philippot, Maria Michela Dell'Anna, Piero Mastrorilli, and Rinaldo Poli. "Rhodium nanoparticles inside well-defined unimolecular amphiphilic polymeric nanoreactors: synthesis and biphasic hydrogenation catalysis." Nanoscale Advances 3, no. 9 (2021): 2554–66. http://dx.doi.org/10.1039/d1na00028d.

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Triphenylphosphine-stabilised rhodium nanoparticles embedded in well-defined core-crosslinked micelles have been generated and used in aqueous biphasic catalysis. The conditions allowing core confinement and efficient catalyst recycle are outlined.
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Fan, Mengyang, Zhengyu Bai, Qing Zhang, Chengyu Ma, Xiao-Dong Zhou, and Jinli Qiao. "Aqueous CO2 reduction on morphology controlled CuxO nanocatalysts at low overpotential." RSC Adv. 4, no. 84 (2014): 44583–91. http://dx.doi.org/10.1039/c4ra09442e.

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The CuxO180-2 catalyst obtained with 3D hierarchical nanosphere structures could catalyze CO2 reduction in aqueous solution with very high catalytic activity and superb selectivity of produced formate, significantly outperforming CuxO catalysts without such special morphology.
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Dissertations / Theses on the topic "Catalyse aqueuse"

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Six, Natacha. "Nouveaux transporteurs et ligands supramoléculaires pour la catalyse organométallique aqueuse." Thesis, Artois, 2011. http://www.theses.fr/2011ARTO0406.

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Le développement des synthèses chimiques "vertes" mobilise actuellement beaucoup d'équipes de recherches scientifiques. La catalyse, et notamment la catalyse organométallique en milieu aqueux, répond bien aux critères de la chimie durable. En effet, ce procédé utilise un solvant vert par excellence: l'eau. Toutefois, ces systèmes sont peu actifs avec des substrats hydrophobes. Il est possible d'utiliser un transporteur supramoléculaire comme les cyclodextrines pour favoriser le transfert de matière entre la phase aqueuse et la phase organique. De nouveaux transporteurs supramoléculaires ont été synthétisés dans un premier temps. Les différents récepteurs mono et ditopiques ont été évalués dans deux réactions de catalyse organométallique: la réaction de clivage allylique (Trost-Tsuji) et la réaction d'hydroformylation d'oléfines grasses. Dans un second temps, une autre approche de l'utilisation des cyclodextrines a été mise en place. Elles permettent de former des complexes d'inclusion avec les phosphines hydrosolubles mises en jeu dans le processus catalytique à basse température et donc d'améliorer le recyclage du catalyseur lorsque le système se refroidit
The development of clean chemical synthesis currently mobilizes a wide range of scientific teams. Aqueous phase organometallic catalysis is a process that uses water as a green solvent. However, these systems are not really active with hydrophobic substrates. We can use supramolecular receptors as cyclodextrins to promote masse transfer between the aqueous and the organic phase. First, news supramolecular receptorss have been synthesized. These various mono and ditopic receptors have been evaluated in two catalytic reactions: allylic cleavage of carbonate and urethane (Trost-Tsuji) and hydroformylation of hydrophobic alkenes. Second, cyclodextrins and PTA-based ligands have been used in a thermocontroled catalytic process. The reaction takes place at high temperature and the catalyst is recycled at low temperature
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Vilcocq, Léa. "Transformation de polyols en phase aqueuse par catalyse hétérogène bifonctionnelle." Thesis, Poitiers, 2012. http://www.theses.fr/2012POIT2274/document.

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Une nouvelle voie de synthèse de carburants à partir de biomasse a été récemment proposée : la transformation directe du sorbitol (sucre hydrogéné d'origine lignocellulosique) en alcanes légers (six atomes de carbone au maximum) en phase aqueuse par catalyse hétérogène bifonctionnelle métal/acide, suivant la réaction : C6O6H14 + 6 H2 → C6H14 + 6 H2O (déshydratation/hydrogénation du sorbitol en hexane). L'enjeu de la thèse est d'identifier des systèmes catalytiques bifonctionnels stables, actifs et sélectifs pour les hydrocarbures à 5 ou 6 atomes de carbone, valorisables dans le pool essence.Les premiers systèmes étudiés sont des catalyseurs à base de platine et de ruthénium supportés sur silice-alumine. Ces catalyseurs ne sont pas stables en milieu hydrothermal et catalysent des réactions indésirables de rupture C-C : la décarbonylation dans le cas du platine (conduisant au CO2) et l'hydrogénolyse ou la méthanation dans le cas du ruthénium. C'est pourquoi de nouveaux systèmes catalytiques ont été préparés par des mélanges mécaniques de catalyseurs métalliques (Pt, Pd, Ir) déposés sur zircone et d'oxydes tungstés (ZrO2-WOx, Al2O3-WOx, TiO2-WOx). Ces systèmes catalytiques présentent une stabilité en phase aqueuse meilleure que pour les catalyseurs à base de silice-alumine. Les sélectivités varient en fonction de la nature de l'oxyde et de la nature du métal utilisés. En particulier, Un nouveau système catalytique, Pt/ZrO2 + TiO2-WOx, (brevet 12/01.546) s'est révélé actif et très sélectif pour les composés en C6. Enfin, les mécanismes réactionnels mis en jeu pour la réaction de transformation du sorbitol ont été discutés en s'appuyant sur des tests de réactivité modèle
A new way of biofuels synthesis was recently proposed: the direct transformation of sorbitol (ex-lignocellulose hydrogenated sugar) into light hydrocarbons (maximum six carbon atoms) in aqueous phase by metal/acid bifunctional heterogeneous catalysis, following the reaction : C6O6H14 + 6 H2 → C6H14 + 6 H2O (dehydration/hydrogenation of sorbitol into hexane). The aim of the PhD work is to identify stable and active bifunctional catalytic systems with selectivity to 5-6 carbon atoms hydrocarbons, which can be further upgraded into gasoline. The first studied systems are platinum and ruthenium catalysts supported on silica-alumina. These catalysts are not stable in hydrothermal medium and catalyse undesired C-C cleavage reactions such as decarbonylation for platinum (leading to CO2) and hydrogenolysis or methanation for ruthenium. That is why new catalytic systems have been prepared by mechanical mixing of metallic catalysts (Pt, Pd, Ir) supported on zirconia and tungstated oxides (ZrO2-WOx, Al2O3-WOx, TiO2-WOx). These catalytic systems present an improved hydrothermal stability compared to the silica-alumina based catalysts. Various selectivities are obtained depending on the oxide and metal natures. Particularly, A new catalytic system, Pt/ZrO2 + TiO2-WOx, (patent 12/01.546), was found to be active and very selective to C6 compounds. Finally, the reaction mechanisms involved in the sorbitol transformation reaction have been discussed, referring to model reactivity tests
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Jauregui, Haza Ulises Javier. "Catalyse en phase aqueuse supportée : hydroformylation d'oct-1-ene : optimisation de l'hydratation et cinétique." Toulouse, INPT, 2002. http://www.theses.fr/2002INPT021G.

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Le travail porte sur l'hydroformylation de l'oct-1-ène par catalyse en phase aqueuse supportée : nous avons cherché à mieux comprendre les mécanismes régissant ce type de catalyse et avons étudié l'influence des paramètres opératoires et des propriétés physico-chimiques de ce système polyphasique (gaz-liquide-liquide-solide) sur les performances (conversion et sélectivité) de la réaction. Nous avons d'abord tracé les isothermes d'adsoption du ligand, TPPTS, et des complexes catalytiques sur les silices : DS 22, DS50, S60, et S200 ; tous ces supports possèdent des capacités d'adsorption importantes. Les isothermes d'adsorption ont été bien représentés par des modèles de Fowler-Guggenheim/Jovanovic-Freundlich. Nous avons mis en évidence l'influence de la concentration en eau et des propriétés physico-chimiques du support sur les performances de la SAPC. Nous avons montré la faisabilité de la SAPC sur phospate apatitique. Nous avons réalisé une étude cinétique, montrant l'influence des pressions en CO et H2, de la concentration en octène et de la température. La loi cinétique proposée est de type Langmuir-Hinshelwood
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Corbel-Demailly, Louis. "Hydrogénation sélective de l’acide lévulinique en phase aqueuse par catalyse hétérogène." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10196.

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L'enjeu de cette thèse est d'identifier des systèmes catalytiques, actifs, sélectifs et stables pour la transformation de l'acide lévulinique (LevA) en 1,4-pentanediol (1,4-PDO) en phase aqueuse. Dans un premier temps, des catalyseurs monométalliques à base de ruthénium (Ru), palladium (Pd), platine (Pt) supportés sur charbon (C) ou sur oxyde de titane (TiO2) sont préparés et testés. Ces premiers résultats ont montré l'importance de certains paramètres sur les performances catalytiques observées. Les catalyseurs à base de Ru se sont révélés les plus actifs et sélectifs en 1,4-PDO (rendement maximal de 50%). L'utilisation de ces catalyseurs monométalliques favorise la formation importante de sous-produits et de réactions de craquage d'où des pertes de carbone transférées en phase gaz. Par imprégnation de différentes teneurs de rhénium (Re) ou de molybdène (Mo) sur ces catalyseurs monométalliques, des catalyseurs bimétalliques Re-Ru et Mo-Ru ont été préparés. L'ajout d'un promoteur permet d'augmenter la vitesse de la réaction de transformation du LevA et améliore significativement la sélectivité en 1,4-PDO (90%). Les mécanismes réactionnels mis en jeu ont été étudiés notamment en s'appuyant sur une modélisation cinétique et sur des tests de réactivité de molécules modèles identifiées comme intermédiaires réactionnels ou produits de la conversion du LevA en 1,4-PDO
The aim of our research project is the hydrogenation of the levulinic acid in aqueous phase into 1,4-pentadeniol using noble metal catalysts (Ru, Pd, Pt) supported on C or TiO2. First results have shown the effect of the metal, the method of preparation or the supports on catalytic performances. Monometallic Ru catalysts are active and selective into 1,4-PDO (maximum yield 50%). By using monometallic catalysts, an important formation of by-products and loss of carbon by cracking reactions was observed. By impregnating various amount of Re or Mo, bimetallic catalysts were prepared. Adding promoter both allows enhancing the reaction rate of LevA hydrogenation and improved the selectivity to 1,4-PDO up to 90%. In order to understand the mechanism, a kinetic modeling and stability test on intermediates or products of the reaction were realized
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Rivière, Maxime. "Transformation de polyols biosourcés par hydrogénolyse en phase aqueuse." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1200/document.

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Synthétiser de l'éthylène glycol et du propylène glycol à partir de ressources renouvelables est un défi pour une chimie durable. L'hydrogénolyse des alditols (xylitol et sorbitol) issus de la biomasse lignocellulosique en glycols est une possibilité. Cette réaction a été effectuée en milieu aqueux dans des conditions opératoires sévères (200°C ; 60 bar H2) en présence d'un catalyseur hétérogène à base de ruthénium (3%Ru/C) et d'une base homogène (Ca(OH)2). Après avoir fait l'étude détaillée des différents mécanismes intervenant au cours de la réaction (épimérisation, décarbonylation, rétro-aldol, etc.), nous avons déterminé un ratio molaire permettant d'obtenir une activité de 93 h-1 et une forte sélectivité en glycols (55%) et en glycérol (15%). Au-delà de ce ratio, le lactate est produit majoritairement au détriment du propylène glycol. Des catalyseurs bifonctionnels (Ru/oxyde basique/C) ont été développés pour s'affranchir de la base homogène. Le catalyseur 3%Ru/MnO(19%)/C présente une forte activité (384 h-1) pour une sélectivité en glycols et en glycérol de 35% et 17%. Cependant une lixiviation du Mn se produit au cours de la réaction en raison de la production de faibles quantités de carboxylates. L'utilisation d'un solvant binaire H2O : ROH (ROH : MeOH ; EtOH ; 1-PrOH et 1-BuOH) en présence d'un catalyseur Ru/MnO/C, a permis d'augmenter les sélectivités en glycols et glycérol jusqu'à 70%. Cependant le dépôt de coke en surface désactive le catalyseur. Des catalyseurs d'oxydes mixtes à base de Mn (ex. : Ru-MnOX-Al) ont également permis d'augmenter la sélectivité en glycols et glycérol jusqu'à 60% pour une activité de 60 h-1 tout en limitant la lixiviation du Mn
The synthesis of ethylene and propylene glycols from renewables is a great challenge for a green chemistry. The hydrogenolysis of alditols (i.e. xylitol and sorbitol) from lignocellulosic biomass into glycols is an interesting process. This reaction was investigated in aqueous media under harsh operating conditions (200°C; 60 bar H2) over Ru-based heterogeneous catalyst (i.e. 3%Ru/C) and a homogeneous basic promotor (i.e. Ca(OH)2). The kinetic studies revealed that several reactions can occur such as epimerization, decarbonylation or retro-aldol. An optimal molar ratio Rmol(OH-/alditol) of 0.13 led to the highest selectivities to glycols (55%) and glycerol (15%) for an activity of 93 h-1. Beyond this ratio, lactate was principally produced to the detriment of propylene glycol. Bifunctional catalysts (Ru/basic oxide/C) were synthetized in order to perform this reaction in neutral conditions. 3%Ru/MnO(19%)/C showed a high activity (384 h-1) and high selectivities to glycols (37%) and glycerol (17%). However, Mn leaching occurred during the reaction (70%) due to the production of small amount of carboxylates. The use of binary solvent H2O: ROH with ROH: MeOH; EtOH; 1-PrOH and 1-BuOH, enhanced the Ru/MnO/C behavior with selectivities to glycols and glycerol up to 70% in spite of the coke formation on the catalysts. Mn-based mixed oxide catalysts in presence of Ru (i.e. Ru-MnOX-Al) were synthetized and led to high selectivities to glycols and glycerol (60%) with an average activity of 60 h-1. The stability of these catalysts was enhanced by decreasing the substrate concentration
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Miquel, Laurent. "Hydroformulation des alcènes lourds catalysée par des complexes dinucléaires du rhodium maintenus en phase aqueuse supportée." Toulouse 3, 1997. http://www.theses.fr/1997TOU30255.

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Les complexes rh#2(stbu)#2(co)#2l#2, ou l represente les ligands hydrosolubles tris(m-sulfonatophenyl)phosphine (tppts) et phospha-7-triaza-1, 3, 5-adamantane (pta), ont ete utilises dans la reaction d'hydroformylation des alcenes lourds. Ces complexes sont maintenus dans un film d'eau a la surface de solides hydrohiles. Il a ete montre que les catalyseurs travaillent a l'interface du film d'eau supporte et de la phase organique. L'examen des selectivites en aldehyde permet de proposser qu'en fait c'est la partie emergee du complexe dans la phase organique qui est responsable de la catalyse. Les differents parametres que sont le rapport ligand libre/complexe du rhodium, la quantite d'eau par rapport au solide, la nature du support, la dispersion du complexe sur le support ont ete examines et optimises. Alors que dans des travaux precedents l'utilisation d'un cosolvant en catalyse biphasique se traduisait par la formation de l'espece hrh(co)(tppts)#3, dans l'approche que nous avons menee le complexe dinucleaire en tppts est recupere en fin de catalyse. Un schema general du mecanisme de cette catalyse est propose, dans lequel, en particulier, le complexe et l'exces de ligand sont maintenus a la surface du solide dans des microreacteurs.
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Messou, Davina Gnamien-Bla. "Valorisation de polyols en phase aqueuse sur catalyseurs bimétalliques supportés pour la production d'hydrocarbures." Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2316/document.

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La biomasse végétale (source de carbone renouvelable) peut être utilisée pour fabriquer des carburants liquides et produits de base pour la chimie. Ainsi depuis environ une dizaine d'années, se développe le procédé APHDO (Aqueous Phase HydroDeOxygenation) de transformation directe en phase aqueuse de polyols d'origine lignocellulosique (comme le sorbitol) en alcanes valorisables (C5-C6). Ce procédé repose sur une catalyse hétérogène bifonctionnelle métal/acide et fait intervenir des ruptures compétitives de liaisons C-C et C-O. L'objectif de la thèse est de mettre au point des systèmes bimétalliques supportés actifs et sélectifs pour la transformation du sorbitol en hexane. La modification d'un catalyseur de référence Pt/SiO2-Al2O3 par ajout de Re, Ir, Pd, Rh et Ru est effectuée par trois techniques de synthèse : co-imprégnation, imprégnations successives et dépôt par réduction catalytique. Les performances des catalyseurs bimétalliques sont comparées à isoconversion de sorbitol à celles des catalyseurs monométalliques parents pour un test catalytique réalisé en autoclave, avec une solution aqueuse à 10% massique de sorbitol, à 240°C et 60 bar de pression totale sous H2. Les produits se répartissent en phase gaz (CO2, alcanes en C1-C6) et liquide (composés oxygénés). Le sorbitane et l'isosorbide sont majoritairement formés en phase liquide, le dernier étant un intermédiaire clé de la transformation du sorbitol dans cette étude. Les catalyseurs Pt-Ru/SiO2-Al2O3 s'avèrent les plus sélectifs pour la réaction, celui préparé par imprégnations successives conduisant à une plus forte proportion de C6 en phase gaz comparé aux deux monométalliques Pt/SiO2-Al2O3 et Ru/SiO2-Al2O3
Plant Biomass (renewable source of carbon) can be used to make liquid fuels and basic products of chemistry. So, from about ten years, the APHDO (Aqueous Phase HydroDeOxygenation) process is developed for the direct transformation in aqueous phase of polyols from Biomass (such as sorbitol) into renewable alkanes (C5-C6). This process involves a metal/acid bifunctional heterogeneous catalysis and competitive C-O and C-C bond cleavages. The aim of the PhD work is to develop supported bimetallic systems active and selective for the transformation of sorbitol into hexane. The modification of a reference Pt/SiO2-Al2O3 catalyst by addition of Re, Ir, Pd, Rh and Ru is carried out by three synthesis methods: co-impregnation, successive impregnations and deposit by catalytic reduction. The performances of bimetallic catalysts are compared at sorbitol isoconversion to those of the parent monometallic catalysts for a catalytic test carried out in an autoclave with an aqueous solution of sorbitol (10 wt%) at 240°C and 60 bar total pressure under dihydrogen. The products are distributed in the gas phase (CO2, C1-C6 alkanes) and in the liquid phase (oxygenated compounds). Sorbitan and isosorbide are predominantly formed in the liquid phase, the latter being a key intermediate of sorbitol transformation in this study. Pt-Ru/SiO2-Al2O3 catalysts are the most selective for the reaction, the one prepared by successive impregnations leads to a higher proportion of C6 in gaseous phase compared to both monometallic Pt/SiO2-Al2O3 and Ru/SiO2-Al2O3 catalysts
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Borsla, Abdou. "Catalyse par colloïdes de rhodium stabilisés en phase aqueuse : hydrogénation d'oct-1-ene." Toulouse, INPT, 2000. http://www.theses.fr/2000INPT005G.

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La catalyse biphasique presente l'avantage d'une separation plus aisee du catalyseur a la fin de la reaction par simple decantation. De l'oxyde de triphenylphosphine m-trisulfonee ainsi que des polymeres tels que l'alcool polyvinylique et la polyvinylpyrrolidone hautement solubles dans l'eau, ont ete utilises pour stabiliser une suspension colloidales de particules actives de rhodium et ceci dans le but de les employer dans l'hydrogenation biphasique de l'oct-1-ene. L'effet de differents parametres sur la stabilite et l'activite de ces nanoparticules sous des conditions plus ou moins severes a ete etudie. Dans le cas de colloides stabilises par l'oxyde de triphenylphosphine m-trisulfonee, il s'est avere que ces colloides sont stables et peuvent donc etre reutilises plusieurs fois dans des conditions de grands rapports molaires entre phosphore et rhodium et de faibles pressions d'hydrogene. Des frequences de rotation deux fois plus elevees que celles observees pour les complexes de coordination ont ete notes. L'emploi des polymeres a ete plus remarquable vu que les frequences de rotation obtenus ici sont trente fois plus importantes que les precedentes. L'alcool polyvinylique a montre moins de potentialites que la polyvinylpyrrolidone quant a sa capacite a stabiliser les colloides. L'etude cinetique de l'hydrogenation et de l'isomerisation de l'octene-1 a ete etudiee avec la presence d'ethanol comme cosolvant permettant une meilleur solubilite du substrat organique en phase aqueuse, et d'une faible concentration de colloides de rhodium afin d'eviter tout phenomene de transfert de matiere. Une dependance d'ordre un, a ete retrouvee par rapport aux concentrations de rhodium et du reactif liquide en phase catalytique, et a la pression d'hydrogene. Le modele cinetique valide sur toute la reaction en tenant compte de l'evolution du milieu et donc de la solubilite des reactifs, retrace les valeurs experimentales avec une bonne concordance.
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Potier, Jonathan. "Nouveaux récepteurs polytopiques à base de cyclodextrines pour la catalyse en phase aqueuse." Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10106/document.

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Pour s’affranchir des problèmes liés à l’hydrophobie des alcènes terminaux dans des réactions d’hydroformylation utilisant des catalyseurs organométalliques hydrosolubles, l’association de polymères et de cyclodextrines (CDs) a été mise à profit pour concevoir de nouveaux additifs et de nouveaux milieux réactionnels. Trois combinaisons polymères/CDs ont été développées, soit par liaison covalente, soit par assemblage supramoléculaire. Premièrement, le greffage covalent de CDs partiellement méthylées sur des chaines polymères a permis d’augmenter significativement les capacités de reconnaissance moléculaire des CDs vis-à-vis d’alcènes possédant des chaines alkyles linéaires de plus de 12 carbones. La coopérativité entre CDs résultant de ce greffage covalent a conduit à une amélioration significative des performances catalytiques. Deuxièmement, des hydrogels supramoléculaires composés de poly(éthylène) glycols et d’α-CDs ont été utilisés avec succès en tant que milieu réactionnel dans des réactions d’hydroformylation biphasique. Enfin, des nouveaux systèmes catalytiques dits « intelligents » ont été obtenus en additionnant les propriétés de reconnaissance moléculaire des CDs partiellement méthylées avec celles de polymères thermosensibles
To overcome the problems related to the hydrophobicity of terminal alkenes in hydroformylation reactions using water-soluble organometallic catalysts, the combination of polymers and cyclodextrins (CDs) has been exploited to develop new additives and new reaction media. Three combinations polymers/CDs have been developed, either covalently or by supramolecular assembly. First, the covalent grafting of partially methylated CDs on polymer chains significantly increased the capacity of molecular recognition of the CDs regarding alkenes with linear alkyl chains longer than 12 carbons. Cooperativity between CDs resulting from the covalent grafting led to a significant improvement in catalytic performance. Second, supramolecular hydrogels composed of poly(ethylene) glycol and α-CDs have been successfully used as a reaction medium in biphasic hydroformylation reactions. Finally, new "smart" catalytic systems have been obtained by summing the molecular recognition properties of partially methylated CDs with those of thermosensitive polymers
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Auneau, Florian. "Transformation du glycérol par catalyse hétérogène : aspects théoriques et expérimentaux." Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00744531.

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Cette thèse s'intéresse à la conversion du glycérol en acide lactique (AL) et 1,2-propanediol (1,2-PDO) par catalyse hétérogène. Le mécanisme de la réaction fait débat, particulièrement au sujet de la première étape, qui peut être une déshydratation ou une déshydrogénation. Il est attendu que ces étapes élémentaires soient influencées par le pH et la nature de l'atmosphère. Ces paramètres ont donc été étudiés expérimentalement, en présence d'un catalyseur au rhodium supporté sur charbon. D'autre part, il y avait un manque de connaissances sur le comportement du glycérol à la surface métallique du catalyseur. Une approche théorique sur une surface modèle a donc été mise en oeuvre dans le champ de la théorie de la fonctionnelle de la densité (DFT), pour examiner les étapes élémentaires et calculer les états de transition correspondants. La combinaison de ces études a montré que la déshydrogénation du glycérol en glycéraldéhyde est la première étape de la réaction sur le catalyseur Rh/C en milieu basique sous atmosphère d'hélium et d'hydrogène. Cette étude a ensuite été étendue à un catalyseur iridium supporté sur charbon, qui a mené à de meilleurs rendements en 1,2-PDO et AL. L'utilisation de ce métal supporté sur carbonate de calcium a permis d'améliorer le rendement en AL, mais l'activité est plus faible. Cependant, ce catalyseur s'est révélé relativement actif dans l'eau à pH neutre, ce qui pourrait conduire à une synthèse plus verte de l'AL. Enfin, les aspects prédictifs de la chimie théorique ont été examinés, pour voir si la réactivité de ce polyol complexe (du point de vue de la chimie théorique) pouvait être modélisée par celle d'un monoalcool sur la surface.
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Books on the topic "Catalyse aqueuse"

1

Joó, Ferenc. Aqueous Organometallic Catalysis. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/0-306-47510-3.

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Aqueous organometallic catalysis. Dordrecht: Kluwer Academic Publishers, 2001.

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Horváth, István T., and Ferenc Joó, eds. Aqueous Organometallic Chemistry and Catalysis. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0355-8.

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Bouic, Phillip Joseph. Ruthenium complexes as potential aqueous romp catalysts. Birmingham: Aston University. Department of Chemical Engineering and Applied Chemistry, 1996.

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Loutchnikov, Andrei. Rhodium-catalyzed coupling reactions of multisubstituted alkenes, arylsubstituted allylic amines, esters and alcohols with arylboronic acids in aqueous media. Ottawa: National Library of Canada, 2003.

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Herrmann, Wolfgang A., and Boy Cornils. Aqueous-Phase Organometallic Catalysis: Concepts and Applications. Wiley & Sons, Limited, John, 2005.

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Herrmann, Wolfgang A., and Boy Cornils. Aqueous-Phase Organometallic Catalysis: Concepts and Applications. Wiley & Sons, Incorporated, John, 2006.

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(Editor), Boy Cornils, and Wolfgang A. Herrmann (Editor), eds. Aqueous-Phase Organometallic Catalysis: Concepts and Applications. 2nd ed. Wiley-VCH, 2004.

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Boy, Cornils, and Herrmann W. A, eds. Aqueous-phase organometallic catalysis: Concepts and applications. 2nd ed. Weinheim: Wiley-VCH, 2004.

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Cornils, Boy, and Wolfgang A. Herrmann, eds. Aqueous‐Phase Organometallic Catalysis. Wiley, 2004. http://dx.doi.org/10.1002/3527602488.

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Book chapters on the topic "Catalyse aqueuse"

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Darensbourg, Donald J., and Cesar G. Ortiz. "Catalysts for an Aqueous Catalysis: Section 3.1." In Aqueous-Phase Organometallic Catalysis, 70–99. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527602488.ch3a.

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Bényei, Attila C. "Hexaaquaruthenate(II) as Catalyst Precursor in Aqueous Organometallic Catalysis." In Aqueous Organometallic Chemistry and Catalysis, 159–71. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0355-8_14.

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Šabata, S., J. Včelák, and J. Hetflejš. "Comparative Study of Biphase Reduction of Carbonyl Compounds Catalyzed by Homogeneous and Water Soluble Ru Catalysts." In Aqueous Organometallic Chemistry and Catalysis, 183–85. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0355-8_17.

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Herwig, Jürgen, and Richard Fischer. "Aqueous biphasic hydroformylation." In Rhodium Catalyzed Hydroformylation, 189–202. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/0-306-46947-2_7.

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Beletskaya, I. P., and A. V. Cheprakov. "Aqueous transition-metal catalysis." In Organic Synthesis in Water, 141–222. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-4950-1_5.

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Herrmann, Wolfgang A., and Fritz E. Kühn. "Aqueous Catalysts for Environment and Safety." In Aqueous-Phase Organometallic Catalysis, 326–47. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527602488.ch5.

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Cornils, Boy, and Wolfgang A. Herrmann. "Aqueous-Phase Catalysis: The Way Ahead." In Aqueous-Phase Organometallic Catalysis, 707–25. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527602488.ch8.

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Cornils, Boy, and Wolfgang A. Herrmann. "Introduction." In Aqueous-Phase Organometallic Catalysis, 1–24. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527602488.ch1.

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Lubineau, André, Jacques Augé, and Marie-Christine Scherrmann. "Basic Aqueous Chemistry: Section 2.1." In Aqueous-Phase Organometallic Catalysis, 25–43. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527602488.ch2a.

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Herrmann, Wolfgang A., and Fritz E. Kühn. "Basic Aqueous Chemistry: Section 2.2." In Aqueous-Phase Organometallic Catalysis, 44–56. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527602488.ch2b.

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Conference papers on the topic "Catalyse aqueuse"

1

Parks, James E. "Mitigation of Sulfur Effects on a Lean NOx Trap Catalyst by Sorbate Reapplication." In ASME 2007 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/icef2007-1628.

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Lean NOx trap catalysis has demonstrated the ability to reduce NOx emissions from lean natural gas reciprocating engines by >90%. The technology operates in a cyclic fashion where NOx is trapped on the catalyst during lean operation and released and reduced to N2 under rich exhaust conditions; the rich cleansing operation of the cycle is referred to as “regeneration” since the catalyst is reactivated for more NOx trapping. Natural gas combusted over partial oxidation catalysts in the exhaust can be used to obtain the rich exhaust conditions necessary for catalyst regeneration. Thus, the lean NOx trap technology is well suited for lean natural gas engine applications. One potential limitation of the lean NOx trap technology is sulfur poisoning. Sulfur compounds directly bond to the NOx trapping sites of the catalyst and render them ineffective; over time, the sulfur poisoning leads to degradation in overall NOx reduction performance. In order to mitigate the effects of sulfur poisoning, a process has been developed to restore catalyst activity after sulfur poisoning has occurred. The process is an aqueous-based wash process that removes the poisoned sorbate component of the catalyst. A new sorbate component is reapplied after removal of the poisoned sorbate. The process is low cost and does not involve reapplication of precious metal components of the catalyst. Experiments were conducted to investigate the feasibility of the washing process on a lean 8.3-liter natural gas engine on a dynamometer platform. The catalyst was rapidly sulfur poisoned with bottled SO2 gas; then, the catalyst sorbate was washed and reapplied and performance was reevaluated. Results show that the sorbate reapplication process is effective at restoring lost performance due to sulfur poisoning. Specific details relative to the implementation of the process for large stationary natural gas engines will be discussed.
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O’Hayre, Ryan, Yingke Zhou, Robert Pasquarelli, Joe Berry, and David Ginley. "Enhancement of Pt-Based Catalysts via N-Doped Carbon Supports." In ASME 2008 3rd Energy Nanotechnology International Conference collocated with the Heat Transfer, Fluids Engineering, and Energy Sustainability Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/enic2008-53078.

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This study experimentally examines the enhancement of carbon supported Pt-based catalysts systems via nitrogen doping. It has been reported that nitrogen-containing carbons promote significant enhancement in Pt/C catalyst activity and durability with respect to the methanol oxidation and oxygen reduction reactions. In order to systematically investigate the effect of N-doping, in this work we have developed geometrically well-defined model catalytic systems consisting of tunable assemblies of Pt catalyst nanoparticles deposited onto both N-doped and undoped highly-oriented pyrolytic graphite (HOPG) substrates. N-doping was achieved via ion beam implantation, and Pt was electrodeposited from solutions of H2PtCl6 in aqueous HClO4. Morphology from scanning electron microscopy (SEM) and catalytic activity measurement from aqueous electrochemical analysis were utilized to examine the N-doping effects. The results strongly support the theory that doping nitrogen into a graphite support significantly affects both the morphology and behavior of the overlying Pt nanoparticles. In particular, nitrogen-doping was observed to cause a significant decrease in the average Pt nanoparticle size, an increase in the Pt nanoparticle dispersion, and a significant increase in catalytic activity for both methanol oxidation and oxygen reduction.
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Akse, James, Richard Wheeler, John Holtsnider, and Layne Carter. "Advanced Aqueous Phase Catalyst Development Using Combinatorial Methods." In 41st International Conference on Environmental Systems. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2011. http://dx.doi.org/10.2514/6.2011-5195.

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Furugori, Ryota, Seiki Ikeda, and Makoto Tanaka. "Effects of Copper Ions and Chelate Agent on Output of Ascorbic Acid Fuel Cell." In ASME 2011 Power Conference collocated with JSME ICOPE 2011. ASMEDC, 2011. http://dx.doi.org/10.1115/power2011-55393.

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A catalyst plays an important role in fuel cell because of promotion of chemical reaction for room temperature type fuel cell. In general, platinum is adopted as a catalyst even though it is very expensive. An ascorbic acid aqueous solution is able to react without catalyst for the oxidation reaction. At first, authors made sure of generation of the electric output using ascorbic acid for fuel without the catalyst. Next, we were able to increase the electric output with adding to metal ions to ascorbic acid aqueous solution. Finally, high and stable electric output was obtained by using the chelating agent.
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Santi, Claudio, Marcello Tiecco, Lorenzo Testaferri, Chun-wing Steven Si, Stefano Santoro, Blerina Gjoka, and Benedetta Battistelli. "Selenium catalyzed oxidation of alkynes in aqueous media." In The 13th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2009. http://dx.doi.org/10.3390/ecsoc-13-00227.

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Gvoić, Vesna, Miljana Prica, Đurđa Kerkez, Ognjan Lužanin, Aleksandra Kulić Mandić, Milena Bečelić-Tomin, and Dragana Tomašević Pilipović. "Fenton-like oxidation of flexographic water-based key (black) dye: a definitive screening design optimization." In 10th International Symposium on Graphic Engineering and Design. University of Novi Sad, Faculty of technical sciences, Department of graphic engineering and design,, 2020. http://dx.doi.org/10.24867/grid-2020-p25.

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Fenton oxidation process has obtained large applicative use for efficient water remediation, whereby overall reaction efficiency could be improved by developing advanced Fenton catalysts. In order to synthesize iron nanoparticles with higher catalytic activity, a simple and eco-friendly method using FeCl3 and aqueous plant extract (oak leaves) was applied in this paper. The nano zero valent iron particles were used as a catalyst in Fenton treatment to remove organic dye from aqueous solution. The objective of this study was to optimize Fenton-like process for the removal of black printing dye using a recently developed design of experiment method - definitive screening design. This novel design framework significantly reduces the number of experiments required to estimate the model parameters and to establish the optimum operation conditions. The experiments were carried out in a batch mode technique, investigating the influence of dye concentration (20 - 180 mgL-1), nanoparticles dosage (0.75 - 60 mgL-1), H2O2 concentration (1 - 11 mM) and pH value of the solution (2 - 10) on the decolorization efficiency. The Fenton-like process resulted with 79% of dye removal from aqueous solution under the optimal process conditions: dye concentration of 180 mgL-1, nanoparticles dosage of 0.75 mgL-1, H2O2 concentration of 1 mM and pH of 2. Increasing the pH value to slightly acidic or near neutral (5-7) medium resulted with slight decrease in the process efficiency (69.14 - 62.63%), but a limitation in the form of sludge generation is noticeable.
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Kim, Kyu-Jung, George Miley, Nie Luo, and Ankeeth Ved. "System Integration Issues for a Direct Sodium Borohydride Fuel Cell (DNBFC)." In ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2009. http://dx.doi.org/10.1115/fuelcell2009-85178.

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A fuel cell for air independent mobile applications using Direct Sodium Borohydride/Hydrogen Peroxide fuels in a low temperature PEM configuration is under development [1, 2]. As part of the development of this unique all liquid fuel cell, we have been studying methods for system integration, including methods for water management, stacking issues involving fluid conductivity control, and the design of a composite catalysis-diffusion layers. [3, 4] The goal is to find optimal conditions (minimum activation, ohmic and transport losses plus maximum run time per fuel loading) in this unique all liquid fuel cell. In contrast to conventional H2/O2 cells, the high electron and ion conductivity of the aqueous solution based fuels introduces special design considerations. For example, in stack design, the path length of flow channels connecting cells must be lengthened to increase the electric resistance which would otherwise introduce serious electrical shorting. With the catalyst coated throughout the diffusion layer, increasing ion conductivity from reaction sites to the PEM region also becomes a key design consideration, involving the porosity and entanglement of catalyst materials. Water management in this type of cell involves unique issues beyond humidification of the PEM which is automatically wetted by the liquid fuels. Here the issue is recirculation of product water from the cathode side back to the borohydride side to prevent reaction product NaBO2 from exceeding its solubility limit. These system integration issues are studied by a coordinated experimental approach which will be described in the presentation.
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Dekamin, Mohammad G., Niaz Kheirabi, and Zahra Karimi. "A green and facile ultrasound-promoted synthesis of thioamide derivatives catalyzed by Cu(I)@Chitosan as a new bio-polymeric nano catalyst in aqueous media." In The 19th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2015. http://dx.doi.org/10.3390/ecsoc-19-a028.

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Xi, Fanxing, Peter Bogdanoff, and Sebastian Fiechter. "Activation of amorphous MoSx as a hydrogen evolving catalyst in aqueous electrolysis." In nanoGe Fall Meeting 2018. València: Fundació Scito, 2018. http://dx.doi.org/10.29363/nanoge.fallmeeting.2018.108.

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Husin, Husni, Adisalamun, Yuliana Sy, Teku Muhammad Asnawi, and Fikri Hasfita. "Pt nanoparticle on La0.02Na0.98TaO3 catalyst for hydrogen evolution from glycerol aqueous solution." In INTERNATIONAL CONFERENCE ON ENGINEERING, SCIENCE AND NANOTECHNOLOGY 2016 (ICESNANO 2016). Author(s), 2017. http://dx.doi.org/10.1063/1.4968326.

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Reports on the topic "Catalyse aqueuse"

1

Haas, P. A. Catalyzed reduction of nitrate in aqueous solutions. Office of Scientific and Technical Information (OSTI), August 1994. http://dx.doi.org/10.2172/10177061.

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Hyder, M. L. The Role of Oxygen in the Copper-Catalyzed Decomposition of Phenylborates in Aqueous Alkaline Solutions. Office of Scientific and Technical Information (OSTI), March 1997. http://dx.doi.org/10.2172/585000.

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