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Hussain, Bashir. "Catalysis via Induced Intramolecularity: Carbonyl-catalyzed Hydration of α-Amino Nitriles." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31177.
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In the last decade, there has been a surge of interest from the chemistry community in developing synthetic catalysts that emulate the remarkable rate accelerations observed for enzymatic reactions. One approach utilized by enzymes involves preorganization of substrate(s) using a favourable binding event to orient the substrate(s) in a reactive arrangement. Although the “induced intramolecularity” is entropically unfavourable, it is facilitated by the enzymes and utilized to accelerate the subsequent chemical transformation. Chemists have often used a conceptually related stepwise approach in which temporary tethers are assembled to induce a temporary intramolecularity. This preorganization often enables difficult intermolecular reactions, and typically leads to increased regio-, chemo-, and stereoselectivity in chemical reactions. Seeking to develop a catalytic approach, we focused our efforts in developing a mild, carbonyl-catalyzed hydration protocol for - and -amino nitriles to give the corresponding - and -amino amide and acid. This work highlights the value of employing induced intramolecularity in accessing structurally important chemical motifs that otherwise require harsh reaction conditions. Additionally, this thesis presents the background material, design process, optimization and scope of this reactivity.
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Mekki-Berrada, Adrien. "Production of fatty nitriles by direct reaction of fatty acids and esters with ammonia : design of catalysts for operating at lower temperature." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10060.
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La synthèse de nitriles gras à partir de ressources renouvelables est un domaine qui attire depuis quelques temps les industries de la parfumerie, des polymères et des biocarburants pour avion. Ce travail de thèse s’est plus particulièrement intéressé à réduire de 100°C la température de travail pour les procédés en phase liquide et gaz, au moyen de catalyseurs plus efficaces. Le procédé en phase liquide a été étudié en terme de catalyse homogène et les formes actives à base de zinc ou indium ont été plus particulièrement détaillées ; des conditions ont été établies pour obtenir une réduction de 50°C de la température de travail. Le procédé en phase gaz a été étudié en terme de catalyse hétérogène, les catalyseurs obtenus ou synthétisés étant caractérisés par microcalorimétrie d’adsorption ; des corrélations entre la conversion de l’ester et l’acidité du lit catalytique ont été trouvées à 300°C, et des conditions expérimentales ont été développées pour obtenir une conversion totale à une température réduite de 100°C sur des catalyseurs choisisThe production of fatty nitriles from renewable sources has lately become attractive for the perfume, polymer and aviation biofuel industry. The present work investigated both liquidand gas-phase processes in the aim of developing catalysts working at 200°C, this is 100°C lower than the state-of-the-art. Homogeneous catalysis was described with zinc and indium based species for the liquid-phase process, succeeding in reducing by 50°C the operating temperature. Heterogeneous catalysts with acid-base features were characterized by adsorption calorimetry and tested in the gas-phase process, leading to correlations between acidity and ester conversion at 300°C, while conditions were found on selected catalysts in order for the process to perform the complete conversion of esters into nitriles at 200°C
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Oike, Keiko [Verfasser]. "Synthesis of α-keto acids and nitriles by enzyme catalysis / Keiko Oike." Bielefeld : Universitätsbibliothek Bielefeld, 2021. http://d-nb.info/1237048605/34.
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Bidange, Johan. "Valorisation de bio-ressources par catalyse au ruthénium." Thesis, Rennes 1, 2013. http://www.theses.fr/2013REN1S181/document.
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Dans un monde où la fin du pétrole est prévisible, l’utilisation de ressources renouvelables, issues de la biomasse, pour la production de bio-carburants et de matières premières pour l’industrie chimique est un domaine de recherche intense. La transformation de dérivés d’acides gras a pu être réalisée par des réactions de métathèse croisée, catalysées au ruthénium. La synthèse de nitriles dits «courts» comme additifs pour le kérosène ainsi que de monomères pour l’industrie des polymères a été développée. La purification des ressources renouvelables a été étudiée. Un traitement thermique, simple à mettre en œuvre, a montré son efficacité pour la réalisation de réactions de métathèse toujours plus efficientes. Enfin, pour des réactions de catalyse toujours plus efficaces, la synthèse de nouveaux complexes de ruthénium à ligand indénylidène chélatant de seconde génération a été entrepriseIn the context of depletion of crude oil, the production of bio-fuels and raw materials from renewable resources for the chemical industry is a topic of tremendous research. The transformation of fatty acid derivatives was developed by using olefin metathesis, using ruthenium catalysts. Short nitriles as kerosene additives and monomers for the polymer industry were synthesized. Purification of the renewable feedstock was studied. A simple thermal treatment was found to promote an increased efficiency for cross-metathesis reactions with fatty acid derivatives. Finally, the synthesis of new second generation ruthenium complexes with a chelating indenylidene ligand was investigated for the development of active and robust catalysts for olefin metathesis reactions
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Downs, Emma. "An Investigation of Transition Metal Catalysts for Cyanohydrin Hydration: The Interface of Homogeneous and Heterogeneous Catalysis." Thesis, University of Oregon, 2014. http://hdl.handle.net/1794/18348.
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Acrylic monomers are important materials that represent a large portion of the economy. The current industrial synthesis hydrates cyanohydrins with sulfuric acid, a process which results in large amounts of waste and significant energy costs. A transition metal catalyzed, acid free hydration of cyanohydrins would be beneficial from both economic and environmental standpoints. However, this reaction is challenging, as many catalysts are poisoned by the cyanide released when cyanohydrins degrade. Therefore the development of a catalyst that is resistant to cyanide poisoning is the ideal method to circumvent these difficulties.
This dissertation describes several cyanohydrin hydration catalysts, with an emphasis on nanoparticle catalysts. These are at the interface between the homogeneous and heterogeneous catalysts that have been explored previously for this reaction. Chapter I surveys previous studies on nanoparticle catalysts for nitrile hydration and their implications for the hydration of cyanohydrins.
Chapter II reports on the homogeneous platinum catalysts [PtHCl(P(NMe2)3)2] and [PtH2(P(NMe2)3)2], exploring secondary coordination sphere effects to enhance nitrile hydration. Chapter III describes another example of this type of complex, [PtH2(P(OMe)3)2], that forms catalytically active nanoparticles under reaction conditions. Explorations of the reactivity of this catalyst with nitriles and cyanohydrins are also described in this chapter.
Chapter IV investigates a silver nanoparticle catalyst with a water soluble phosphine (1,3,5-triaza-7-phosphaadamantane) ligand for its activity towards the hydration of nitriles and cyanohydrins. The results of the degradation of the nanoparticles in the presence of cyanide are also described. Chapter V reports on the preparation and examination of a solid supported nickel catalyst for cyanohydrin hydration. Finally, Chapter VI describes how these investigations have made progress towards the development of a cyanide resistant nitrile hydration catalyst.
This dissertation includes previously published and unpublished co-authored material.2015-09-29
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Glennie, Sarah. "Catalytic hydrogenation of nitriles to amines." Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/54626/.
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The adiponitrile hydrogenation reaction, relevant for the production of aminocapronittile and hexamemyldiamine precursors for Nylon 6 and Nylon 6, 6 respectively, has been investigated. Three different reactor systems were used trickle-bed reactor, fixed-bed gas-phase reactor and the stirred-tank autoclave reactor. This meant comparisons between flow system and batch process could be made. Supported metal catalysts were investigated as alternatives for the currendy industrially used Raney catalyst. Precious metals, specifically rhodium, were compared with the base metals nickel and cobalt on the basis of activity and selectivity. Mixed metal alloy catalysts were also prepared and comparisons drawn. Finally a range of supports were also tested. Both flow systems were found to be of limited use with problems attributed to the practical applications of the reactor systems. Using Autoclave activity data as a standard it was possible to define differences in activity between each of the catalysts prepared.
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Parratt, Julian Simon. "Enzyme catalysed nitrile hydrolysis." Thesis, University of Exeter, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357898.
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Bond, G. "Fe/MgO catalysts for the hydrogenation of nitriles." Thesis, University of Bath, 1992. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317377.
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Beard, Timothy Mark. "Enzyme catalysed hydrolysis of nitriles and amides." Thesis, University of Huddersfield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363237.
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Described in this thesis is the isolation of two microorganisms containing a nitrile hydratase and amidase to effect the enantioselective hydrolysis of a-substituted nitriles to their corresponding amides and acids. Isolate NP3854 was identified as an atypical Rhodococcus sp. The nitrile hydratase proved to be non-selective for all the substrates tested. However, carboxylic acids with excellent enantiomeric excess were obtained from a large number of amides. X R~CN H nitr-il-e--h-y-d-r.a~tase ~X amidas.e RH CONH2 X R~"""CO H H 2 Optically active acids with an enantiomeric excess of, generally, >98 %, were obtained when X = NH2, Me and Cl, but proved to be racemic for OH and Br. R could be a variety of aromatic, cyclic and acyclic alkyl residues without adversely affecting the enantioselectivity. The pH-activity profile was determined for the amidase of NP3854 using propionamide as the substrate. From this data, coupled with inhibition studies, it may ,.tentatively be suggested that the amidase has a histidine residue in the active site, which may act as a general base for a serine amino acid. The pH-activity profile was determined for 2-amino-2-phenylacetamide 2b, and this suggested that the unprotonated form of the amine acted as the substrate. Within a pH range of 3 - 9 the enantiomeric excess remains high (>98 %) and experimentally invariant. The amidase was found to have a temperature optimum of 60°C and could tolerate 20 % THF with a loss of only 15 % activity. Attempts made to hydrolyse 4,5,6-amino nitriles and amides to the corresponding amino acids and isolate any reaction intermediates failed. This was presumed to be due to the large fraction of the unprotonated amine due to the higher pKa (- 9 - 10).
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Lester, Roy P. "Catalytic activation of nitriles towards nucleophilic addition." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28449/.
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The work presented in this thesis is focused on the development of a multifaceted approach to the catalytic activation of nitriles. To develop a versatile method for catalytic nitrile activation two probes were utilised; i) the development of a direct synthesis of allylic amides from the corresponding allylic alcohol and nitrile using a commercial platinum salt, together with a detailed mechanistic investigation into the process, ii) the direct synthesis of 2-bezoxazole from the corresponding 2-aminophenol and nitrile with the aid of a commercial platinum salt as well as the use of alcoholic solvents. In addition to nitrile activation a preliminary study on the application and further functionisation of 2-trichlorobenzoxazoles was undertaken. i) A novel multifaceted approach to the direct synthesis of allylic amides via the catalytic activation of di- and trichloroacetonitrile will be discussed. This one-pot methodology relies on the same platinum catalyst to activate a nitrile towards nucleophilic attack of allylic alcohol as well as activate the newly formed allylic imidate towards a [3,3]-sigmatropic rearrangement, which produced a number of allylic amides. In addition to the development of the one-pot allylic amide methodology a number of mechanistic studies including 1H, 13C{1H} and gas chromatography were under taken to better understand the process. ii) The second probe used to identify the versatility of this multifaceted catalyst approach to nitrile activation was the direct synthesis of 2-benzoxazoles. Within this study it was discovered that protic solvents were able to activate di- and trichloroacetonitrile efficiently towards nucleophilic attack of the nitrogen nucleophile. From this discovery a mild and effective synthesis of a variety of di- and trichlorobenzoxazoles was developed in which the solvent was acting as the activating agent towards nucleophilic attack. iii) Preliminary results will also be reported on the novel manipulation of the trichloromethyl moiety of benzoxazoles. Within this study two efficient methodologies for the selective synthesis of 2-(pyrrolidin-1-yl)benzo[d]oxazole and benzo[d]oxazol-2-yl(pyrrolidin-1-yl)methanone were developed from a single starting material. These results show a positive direction for the study into diversity oriented synthesis to form a number of different small molecules from a single starting material by altering the conditions of the reaction.
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McKay, David. "Catalysis over molybdenum containing nitride materials." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/174/.
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Reactions involving nitrogen transfer/ fixation are of great industrial interest, as novel processes could help industries meet their increasingly challenging economic and environmental targets. An example of this could be the direct synthesis of aniline from benzene, which would avoid the lengthy, uneconomic, and environmentally unfriendly process currently employed. This work explores the reactivity of bulk and supported transition metal nitride catalysts, with particular emphasis on the possible reactivity of lattice nitrogen within bulk nitride catalysts. The experimental work has focussed on two main objectives: determining the most active transition metal nitride catalyst for ammonia synthesis, and hydrogenating these materials to in the absence of N2 to produce reactive NHx species. These materials were then tested for the possible direct synthesis of aniline from benzene by entrapment of reactive NHX species. The second objective was to achieve nitrogen reactivity with nitride catalysts akin to the Marsvan Krevelen mechanism observed in oxidation catalysis. It has been shown that the binary nitrides, γMo2Nand βMo2N0.78, have comparable ammonia synthesis activities although measurements indicate that βMo2N0.78 may have a much greater activity on a surface area normalised basis. Meanwhile the δMoNphase has an intermediate surface area, but very low activity. The influence of morphology in the ammonia synthesis reaction was investigated by testing nanorod forms of βand γphase molybdenum nitrides and comparing their ammonia synthesis activities with molybdenum nitride powders. Morphology was found to have little effect on the reaction and the influence of structure sensitivity is thought to be limited in this case. What was apparent, was that the highly specific temperature programmed reaction synthesis required to prepare γMo2Nproduced an ammonia synthesis catalyst with no catalytic advantage over one that is prepared in mixtures of H2/N2 (βMo2N0.78). The influence of preparation on the ammonia synthesis activity of ternary nitride catalysts was also investigated by preparing materials in NH3 or H2/N2 atmospheres. Treatment of iron and cobalt molybdenum oxide under H2/N2 was not sufficient to yield a pure phase nitride, however NiMoO4 was fully reduced to Ni2Mo3N. Co3Mo3N, prepared using NH3, was the most active of the ternary nitride catalysts tested, and preparing the materials in H2/N2 failed to increase the activity, with the exception of Ni2Mo3N. Reaction of Co3Mo3N with H2/Ar significantly decreased the nitrogen content of the material, and it is believed that a previously unknown eta12 Co6Mo6N phase has been formed as a result of the nitrogen removal. Hydrogen was shown to be essential to induce this change, despite the fact that most of the eliminated N ended up in the form of N2. Prolonged treatment with H2/Ar at elevated temperature did not remove any additional nitrogen. It is believed that the incomplete loss of nitrogen is a direct consequence of the migration of nitrogen between crystallographic sites as the stoichiometry is reduced. In the case of iron and nickelmolybdenum nitrides the loss of nitrogen was evidenced by combustion analysis, however no new phases of material were formed. Similar experiments, with conducted with different molybdenum nitride polymorphs have shown the removal of nitrogen with a mixed phase of constituent metal and nitrided species, with only βMo2N0.78 fully decomposing to the pure metal. The loss of nitrogen, and hence its potential for reaction, is evident. However, in all cases the predominant form of lost nitrogen is N2, which is believed to be a consequence of the thermodynamics of ammonia decomposition at higher temperatures. Restoration of stoichiometry by treatment with H2/N2 has been observed for a number of materials, i.e. Co3Mo3N, γMo2N. In the case of Co6Mo6N, the NH3 synthesis activity has been found to be comparable with Co3Mo3N. HZSM5 supported nitride catalysts were also tested for ammonia synthesis and it was observed that the introduction of iron as a dopant has significant promotional effects. XPS evidence confirmed the presence of Fe0 in the material, in addition to the molybdenum (oxy)nitride species observed for MoO3/HZSM5. FTIR spectroscopy was used to conduct isotopic nitrogen exchange experiments over nitrided HZSM5 and MoO3/HZSM5. Under the conditions of the experiment, it was shown that the presence of “molybdenum nitride” facilitated the exchange of 15N2 with zeolite framework NHx species. This shows that supported γMo2Nspecies can be a source of reactive and mobile Nspecies, potentially opening up possibilities for its application as a source of spillover nitrogen. A potential route for the direct synthesis of aniline from benzene by hydrogenating ternary nitrides with benzene in the feed, trapping the possible reactive nitrogen species, was investigated. GCMS data showed the no reaction occurred, as only benzene was found in the David Mckay Abstract iv product condensate. In all cases a significant amount of carbon was incorporated/ deposited on the catalysts. In the case of the cobalt molybdenum sample, the XRD data confirmed the conversion of nitride to the carbide, however postreaction XRD of the iron and nickel samples did not indicate carbide formation.
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Smith, Andrew Michael. "Bimetallic catalysts for the hydrogenation of amides and nitriles." Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433411.
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Chaumonnot, Alexandra. "Hydrocyanation et isomérisation de nitriles allyliques : études catalytique et mécanistique." Toulouse 3, 2001. http://www.theses.fr/2001TOU30213.
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Clutterbuck, Lisa. "The catalytic, asymmetric synthesis of cyanohydrins and amino nitriles." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505844.
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McMillan, Liam. "The palladium catalysed hydrogenation of multi-functional aromatic nitriles." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/3175/.
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A series of model compounds and a commercial Pd/C catalyst were used to study the issues relevant to the hydrogenation of aromatic nitrile molecules that are associated with an industrial agrichemicals process, where a primary amine is the target product. Benzonitrile hydrogenation was found to be converted to high value benzylamine before an unexpected hydrogenolysis reaction led to the loss of ammonia to ultimately yield toluene as the final product. Indeed, gas phase infrared studies unambiguously showed the formation of ammonia for the first time. On closer investigation, the reaction was found to be a consecutive process where the order of reaction changed from first order for hydrogenation to zero order for hydrogenolysis. Co-adsorption studies proved that the two reactions occurred independently on two distinct Pd sites. The choice of catalyst and the use of an acid additive were shown to improve selectivity to benzylamine. A dramatic change was noted when the aliphatic chain was extended. For benzyl cyanide hydrogenation, conversion was observed but, by way of a “spillover” process, the amine product was retained by the catalyst. Extending the chain further resulted in a complete loss in reactivity showing that electronic and structural factors had a major effect on activity and product distribution. Mandelonitrile hydrogenation required an acid additive to facilitate conversion since a series of co-adsorption studies showed that under neutral conditions an intermediate hydroxyamine acted as a poison. Recycling of the catalyst showed that a cumulative poisoning effect was evident, but manipulation of Pd particle shape and size resulted in an extended lifetime and superior selectivity. Introducing additional functionality to the aromatic ring meant that stabilised imine species were observed in the liquid phase. The nature of the substituent also affected product distribution and catalyst lifetime. MeO-, Me- and Cl-substituents all showed signs of reduced catalyst performance, but an OH-substituent exhibited greater durability, albeit with reduced selectivity to the primary amine. These systems also indicated the presence of a high energy site on the catalyst, which was responsible for the formation of secondary and tertiary amines.
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Gilpin, Lauren F. "The liquid phase hydrogenation of aromatic nitriles over supported palladium catalysts." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/7053/.
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Dai, Huiguang. "Iron and Cobalt Based Catalysts for the Hydrogenation of Esters, Amides and Nitriles." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1522319401761328.
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Knapp, Spring Melody, and Spring Melody Knapp. "Investigation of Secondary Coordination Sphere Effects for Cyanohydrin Hydration with Transition Metal Catalysts." Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12362.
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The synthesis of high value acrylic monomers is currently done industrially via cyanohydrin hydration using concentrated acids, resulting in large quantities of useless byproducts. This current process is energy intensive and lacks atom economy; therefore, alternative cyanohydrin hydration strategies are under investigation. Ideally, cyanohydrin hydration would be done using organometallic nitrile hydration catalysts. Cyanohydrin hydration with these catalysts is challenging, because it needs to be done at low temperatures and under acidic conditions to reduce cyanohydrin degradation and catalyst poisoning with cyanide.
This dissertation describes the reactivity of [Ru(#951;10000-01-01
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Zaki, Mohamed. "Réactivité et hémisynthèse des constituants majoritaires, de type eudesmanes, contenus dans des extraits de Dittrichia Viscosa." Thesis, Orléans, 2015. http://www.theses.fr/2015ORLE2014/document.
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Au cours de ces dernières années, les sesquiterpénoïdes de type eudesmane et leurs activités biologiques font l'objet de nombreuses études phytochimiques et pharmacologiques, ainsi que des recherches de voies de synthèse et d'hémisynthèse. Pour notre part, nous nous sommes intéressés à la synthèse des analogues de types eudesmanes par fonctionnalisation des constituants majoritaires de Dittrichia Viscosa. Dans le premier chapitre, nous avons donné un rappel bibliographique sur l’aspect botanique de Dittrichia Viscosa, ainsi qu’une description phytochimique qui montre que cette plante renferme différents constituants : terpénödes, flavonoïdes, phénylpropanoïdes et polycétides présentant des propriétés pharmacologiques variés. Dans le deuxième chapitre, et après un rappel bibliographique sur les différents types d’eudesmane et l’extraction et la purification des produits majoritaires de Dittrichia Viscosa (l'acide α-costique, l'acide ilicique et la tomentosine), nous avons réalisé l’étude des réarrangements des époxy-eudesmanes par catalyse acide et la synthèse de l'aldéhyde α-costal et ses analogues. Nous avons aussi mise au point des conditions réactionnelles de fonctionnalisation de la double liaison C11-C13 par couplage de Heck permettant l’accès à des librairies d'eudesmanes arylés en position 13. En fin, le dernier chapitre est consacré à l’étude de la réactivité de la tomentosine vis-à-vis des additions nucléophiles (type Addition de Michael) et des additions 1,3 dipolaire (des nitrones et des oxydes de nitrile) sur la double liaison conjuguée exo-cycliqueIn recent years, the sesquiterpenoids eudesmane type and their biological activities are subject to numerous phytochemical and pharmacological studies and research of synthetic and semisynthetic routes. For our part, we are interested in the synthesis of similar types of eudesmanes by functionalization of the major constituents of Dittrichia Viscosa. In the first part we gave a bibliographical recall on the botanical aspect of Dittrichia Viscosa and a phytochemical description shows that this plant contains various constituents: terpénödes, flavonoids, phenylpropanoids and polyketides with various pharmacological properties. In the second part, and after giving a bibliographical recall of the different types of eudesmane and extraction and purification of major products of Dittrichia Viscosa (α-costique acid, ilicique acid and tomentosin), we realized the study of epoxy eudesmanes rearrangements by acid catalysis and the synthesis of α-costal aldehyde and its analogues. We also focus on the reaction conditions for functionalization of C11-C13 dual link Heck coupling allowing access to libraries eudesmanes aryl in position 13. In the last part, we are interested to the study of the reactivity of the tomentosin with nucleophilic additions (type Michael Addition) and 1,3-dipolar additions (nitrones and nitrile oxides) on the double link exo-cyclic combined
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Lagriffoul, Pierre-Henri. "Hydratation énantiosélective des nitriles alpha-aminés catalysée par des composés cétoniques chiraux." Montpellier 2, 1992. http://www.theses.fr/1992MON20013.
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L'hydratation enantioselective des alpha-aminonitriles catalysee par des composes cetoniques chiraux, mise en evidence par notre groupe de recherche, est etendue dans cette these aux alpha-aminonitriles precurseurs d'acides amines comme la phenylalanine, la phenylglycine ou la valine. La composition du solvant (et particulierement la teneur en cosolvant alcoolique) est, dans ce processus catalytique, un parametre determinant de l'efficacite du catalyseur cetonique mais aussi de son enantioselectivite. Le caractere pseudoenzymatique de cette catalyse enantioselective est souligne. Dans une seconde partie, apres avoir defini les meilleures conditions d'immobilisation de cetones achirales sur support acrylique, une resine cetonique chirale a ete preparee. La faisabilite de l'hydratation enantioselective des alpha-aminonitriles en presence de ce catalyseur supporte chiral est demontree
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Dumoulin, Michel. "Alcoxycarbonylation d'oléfines fonctionnelles catalysée par des composés du cobalt et du ruthénium." Lyon 1, 1997. http://www.theses.fr/1997LYO10359.
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Dans le cadre de la recherche d'une nouvelle voie d'acces a l'epsilon-caprolactame, la methoxycarbonylation du pentene-3-nitrile a ete examinee. Catalysee par l'octacarbonyldicobalt, cette reaction conduit a la formation d'une grande quantite de cyanovalerate de methyle. Les produits secondaires sont le valeronitrile, des diesters, des aldehydes et des cyanoesters ramifies. L'utilisation des pentenenitriles isomeres et la mise en oeuvre de la reaction dans l'ethanol ou l'isopropanol a la place du methanol permet d'approfondir certains aspects du mecanisme reactionnel. La formation de l'espece active, l'hydrurotetracarbonylcobalt, resulterait du transfert d'un proton hydroxylique d'une molecule d'alcool coordonnee au cobalt(ii) vers l'anion tetracarbonylcobaltate(-i). Ces deux especes du cobalt sont issues de la dismutation de l'octacarbonyldicobalt en milieu alcoolique. La coordination de la fonction nitrile du substrat sur le cobalt(ii) favoriserait sa methanolyse en ester methylique et serait a l'origine de la forte proportion en 2-cyanovalerate de methyle par rapport aux autres cyanoesters ramifies. En presence d'un cocatalyseur au ruthenium, un effet de synergie avec le cobalt est observe. Il se traduit par un accroissement simultane des vitesses d'isomerisation du substrat et de formation des cyanoesters, du valeronitrile et des aldehydes. L'hydrurotetracarbonylcobalt est l'espece active commune a ces trois composes et sa formation est l'etape cinetiquement limitante. Le ruthenium faciliterait sa formation et serait responsable de la reduction d'une partie du cobalt(ii) en complexe carbonyle du cobalt(-i). La methoxycarbonylation d'esters methyliques insatures met en evidence l'existence d'interactions intramoleculaires dans les complexes alkyl- et acylcobalt. Elles seraient responsables de la plus faible proportion de reduction du substrat ainsi que de la distribution des diesters.
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Metzke, Sarah. "Synthesis and characterization of transition metal nitrides and carbides for catalysis and electrochemistry application." Bachelor's thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2014/6983/.
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It was the goal of this work to explore two different synthesis pathways using green chemistry. The first part of this thesis is focusing on the use of the urea-glass route towards single phase manganese nitride and manganese nitride/oxide nano-composites embedded in carbon, while the second part of the thesis is focusing on the use of the “saccharide route” (namely cellulose, sucrose, glucose and lignin) towards metal (Ni0), metal alloy (Pd0.9Ni0.1, Pd0.5Ni0.5, Fe0.5Ni0.5, Cu0.5Ni0.5 and W0.15Ni0.85) and ternary carbide (Mn0.75Fe2.25C) nanoparticles embedded in carbon.
In the interest of battery application, MnN0.43 nanoparticles surrounded by a graphitic shell and embedded in carbon with a high surface area (79 m^2/g) were synthesized, following a previously set route.The comparison of the material characteristics before and after the discharge showed no remarkable difference in terms of composition and just slight differences in the morphological point of view, meaning the particles are stable but agglomerate. The graphitic shell is contributing to the resistance of the material and leads to a fine cyclic stability over 140 cycles of 230 mAh/g after the first charge/discharge and coulombic efficiencies close to 100%. Due to the low voltage towards Li/Li+ and the low polarization, it might be an attractive anode material for lithium ion batteries. However, the capacity is still noticeably lower than the theoretical value for MnN0.43. A mixture of MnN0.43 and MnO nanoparticles embedded in carbon (surface area 93 m^2/g) was able to improve the cyclic stability to over 160 cycles giving a capacity of 811 mAh/g, which is considerably higher than the capacity of the conventional material graphite (372 mAh/g). This nano-composite seems to agglomerate less during the process of discharge. Interestingly, although the capacity is much higher than of the single phase manganese nitride, the nano-composite seems to only contain MnN0.43 nanoparticles after the process of discharge with no oxide phase to be found.
Concerning catalysis application, different metal, metal alloy, and metal carbide nanoparticles were synthesized using the saccharide route. At first, systems that were already investigated before, being Pd0.9Ni0.1, Pd0.5Ni0.5, Fe0.5Ni0.5 and Mn0.75Fe2.25C using cellulose as the carbon source were prepared and tested in an alkylation reaction of toluene with benzylchloride. Unexpectedly, the metal alloys did not show any catalytic activity, but the ternary carbide Mn0.75Fe2.25C showed fine catalytic activity of 98% conversion after 9 hour reaction time (110 °C).
In a second step, the saccharide route was modified towards other carbon sources and carbon to metal ratios in order to improve the homogeneity of the samples and accessibility of the particle surfaces. The used carbon sources sucrose and glucose are similar in their basic structure of carbohydrates, but reducing the (polymeric) chain length. Indeed, the cellulose could be successfully replaced by sucrose and glucose. A lower carbon to metal ratio was found to influence the size, homogeneity and accessibility (as evidenced by TEM) of the samples. Since sucrose is an aliment, glucose is the better choice as a carbon source.
Using glucose, the synthesis of Cu0.5Ni0.5 and W0.15Ni0.85 nano-composites was also possible, although the later was never obtained as pure phase. These alloy nano-composites were tested, along with nickel0 nanoparticles also prepared with glucose and on their catalytic activity towards the reduction of phenylacetylene.
The results obtained let believe that any (poly) saccharide, including lignin, could be used as carbon source. The nickel0 nano-composites prepared with lignin as a carbon source were tested along with those prepared with cellulose and sucrose for their catalytic activity in the transfer hydrogenation of nitrobenzene (results compared with exposed nickel nanoparticles and nickel supported on carbon) leading to very promising results.
Based on the urea-glass route and the saccharide route, simple equipment and transition metals, it was possible to have a one-pot synthesize with scale-up possibilities towards new material that can be applied in catalysis and battery systems.Im Rahmen dieser Arbeit wird sowohl die Synthese von Mangannitrid- und -oxid-Nanopartikeln, als auch die Synthese verschiedener Metall- und Legierungsnanopartikel untersucht. Einen Schwerpunkt stellt dabei die Optimierung der Synthese unter den Gesichtspunkten der Nachhaltigkeit dar, was sich insbesondere in der Verwendung diverser nachwachsender Rohstoffe als Kohlenstoffquelle äußert. Für eine mögliche Anwendung in Akkumulatoren werden mit Graphit ummantelte MnN0.43-Nanopartikel mit einer großen Oberfläche (79 m^2/g) synthetisiert. Diese werden exemplarischen Ladezyklen unterzogen, wobei eine strukturelle und auch elektrochemische Stabilität festgestellt werden kann. Eine Mischung der Mangannitride mit Manganoxiden führt zu einer weiteren Verbesserung der Ladekapazität und einer weiteren Oberflächenvergrößerung (93 m^2/g). Die Langlebigkeit der Strukturen wird durch die Einbettung der Nanopartikel in Kohlenstoff unterstützt und kann zu einer Anwendung als Anodenmaterial in den heutzutage vielfach verwendeten Lithiumionen-Akkus führen. Im Sinne der Nachhaltigkeit ist auch die Entwicklung von Katalysatoren. Dabei soll insbesondere die Verwendung von Lignin, was als Bestandteil vieler Pflanzen zwar leicht verfügbar, aber unglücklicherweise bisher chemisch unverwertbar ist, fokussiert werden. Um sich diesem Ziel zu nähern und entsprechende Mechanismen zur Reduktion des Lignins zu entwickeln, werden in dieser Arbeit zunächst verschiedene Kohlenstoffquellen (wie Cellulose, Sucrose und Glucose) zur Synthese von reduktiven Katalysatoren untersucht. Der Kohlenstoff dient dabei sowohl als preiswertes Reduktionsmittel für Metallsalze zur Gewinnung von Metallnanopartikel als auch zur Stabilisierung ebendieser. Es werden vielfältige Legierungen mit Nickel (z.B. Pd0.9Ni0.1, Pd0.5.Ni0.5, Fe0.5.Ni0.5, und Cu0.5.Ni0.5) aber auch ternäre Carbide (z.B. Mn0.75Fe2.25C) erhalten, die schon in ersten Alkylierungs- und Hydrierungsreaktionen ein großes Potential als Katalysatoren zeigen. Um die erhaltenen Nanopartikel in zukünftigen Anwendungen nutzbar zu machen, ist eine ausführliche Charakterisierung unabdingbar. Auch die Ergebnisse der zahlreichen durchgeführten Analysen werden in dieser Arbeit zusammengestellt und bilden gemeinsam mit den optimierten Syntheserouten einen tiefgreifenden Überblick über dieses Forschungsfeld.
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Kim, Jung-Hee. "Developing artificial proteases and nucleases : catalytic hydrolysis of unactivated amides, nitriles and phosphates." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39317.
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Cis-diaqua cobalt complex ((L)Co(III)(OH$ sb2) sb2 rbrack sp{3+}$ promoted hydrolyses of phosphate esters, nitriles and carboxy amides are examined (L represents 1,4,7,10-tetraazacyclododecane (cyclen) and its N-methylated derivatives). ((Cyclen)Co(OH$ sb2) sb2 rbrack sp{3+}$ is more active than any other catalysts reported to date for hydrolyzing dimethyl phosphate, acetonitrile and formyl morpholine.((Cyclen)Co(OH$ sb2) sb2 rbrack sp{3+}$ efficiently hydrolyzes dimethyl phosphate under mild conditions (k = 3.7 $ times$ 10$ sp{-5}$ M$ sp{-1}$ sec$ sp{-1}$ at pD 6.3, 60$ sp circ$C). This represents the first hydrolysis of dimethyl phosphate (P-O bond cleavage) at neutral pH. Mechanism for the cobalt complex promoted hydrolysis of dimethyl phosphate and its implication on the role of metal ions in ribozymes is discussed.
((Cyclen)Co(OH$ sb2) sb2 rbrack sp{3+}$ catalyzes the hydration of nitriles to amides. Acetonitrile coordinated to the cobalt complex is hydrated 10$ sp9$ times more rapidly than the uncoordinated acetonitrile at pH 7 and 40$ sp circ$C. Catalytic turnover for the hydration reaction is demonstrated for the first time with the Co(III) complex. Chelated benzamide, a key intermediate in the catalytic hydration of benzonitrile, is isolated and its crystal structure determined. Detailed kinetics and mechanistic analyses of the cobalt complex catalyzed hydration of acetonitrile including the equilibrium constant for complexation of acetonitrile to the cobalt complex (K = 0.6 M$ sp{-1})$ are reported. Synthetic utility of the catalyst including acrylamide production is discussed.
((Cyclen)Co(OH$ sb2) sb2 rbrack sp{3+}$ efficiently hydrolyzes formyl morpholine under mild conditions (k = 7.97 $ times$ 10$ sp{-5}$ M$ sp{-1}$ sec$ sp{-1}$ at pD 6, 60$ sp circ$C). The equilibrium constant for complexation of formyl morpholine to the cobalt complex is 0.4 M$ sp{-1}.$ The equilibrium constant for complexation of amides to metal complexes had not been previously measured. The efficiency and mechanism of the cobalt complex for hydrolyzing amides are compared to those of carboxypeptidase A.
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Schwartz, Viviane. "Preparation and Reactivity of Niobium-Containing Hydrotreating Catalysts." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/26368.
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A series of niobium-containing nitride and carbides were prepared by a temperature-programmed synthesis method. The catalysts synthesized comprised a monometallic niobium oxynitride and a new bimetallic oxycarbide supported system, Nb-Mo-O-C/Al₂O₃ (Mo/Nb = 1.2; 1.6; 2.0).
In the case of the niobium oxynitride, the progress of formation was analyzed by interrupting the synthesis at various stages. The effect of the heating rate on product properties was also investigated. The solid intermediates and the final niobium oxynitride were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), elemental analysis (CHNS), and gas adsorption techniques. The solid state transformation occurred directly from Nb₂O₅ to NbNxOy without any suboxide intermediates.
The bimetallic supported oxycarbide materials were also characterized by X-ray diffraction (XRD), gas adsorption techniques, X-ray photoelectron spectroscopy (XPS), and near-edge X-ray absorption fine structure (NEXAFS). It was found that the electronic properties of the oxycarbide were modified by the interaction with the Al₂O₃ support, and that most of the oxygen atoms were associated with the niobium rather than the molybdenum atom. All of the niobium-containing catalysts were tested in a three-phase trickle-bed reactor for the simultaneous hydrodenitrogenation (HDN) of quinoline and hydrodesulfurization (HDS) of dibenzothiophene. The niobium oxynitride presented low HDS activity and moderate HDN activity, whereas the supported bimetallic oxycarbide was found to be highly active for both, HDN and HDS, demonstrating higher activities than the commercial sulfided Ni-Mo/Al₂O₃ when compared on the basis of active sites.
In addition to these studies a comprehensive investigation of the HDN reaction mechanism was carried out over bulk unsupported Mo₂C, NbC, NbMo₂-O-C, and compared with the mechanism over a sulfide catalyst, MoS₂/SiO₂. For this purpose, a comparison of the HDN rate of a series of isomeric amines was performed, and the reaction occurred mainly through a β-elimination mechanism for all catalysts. Temperature programmed desorption of ethylamine was used to investigate the acid properties of the catalytic surfaces, and a good agreement between the specific rate of reaction and the number of Brønsted acid-sites was obtained. Infrared spectroscopy showed that the amines interacted with acidic centers to form adsorbed quartenary ammonium species. The deamination reaction over the carbide and sulfide catalysts probably occurs by a concerted push-pull mechanism involving basic sulfur species and Brønsted-acidic centers. In order to obtain more insight into the mechanism a study of the pyridine HDN network was carried out.All of the catalysts showed the same activity trend: the reactivity of n-pentylamine was high, while those of piperidine and pyridine were relatively low. The carbide catalysts showed higher selectivity towards HDN products than the sulfide catalyst at the same conversion levels. The higher selectivity was related to the higher ratio (r = k₂/k₁) between the rate constants of the two consecutive reactions, hydrogenation of pyridine (k₁) and ring opening of piperidine (k₂). The order of activity of the carbides and sulfide differed considerably depending on the substrate. However, for the pyridine reaction network the similarity in product distribution suggested that a similar surface composition, a carbosulfide, was attained during the reaction.Ph. D.
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Guilet, Richard. "Alkylation du phénylacétonitrile en catalyse par transfert de phase solide-liquide assistée par ultrasons. Application à la synthèse d'une lactone." Toulouse, INPT, 1995. http://www.theses.fr/1995INPT026G.
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L'alkylation des nitriles aromatiques et en particulier du phenylacetonitrile presente un grand interet dans l'industrie pharmaceutique. Cette alkylation se fait en general a l'aide d'une base forte telle que l'amidure de sodium, dont l'utilisation a l'echelle industrielle presente certains risques (stockage, transport). L'auteur presente une etude sur des conditions operatoires plus douces pour l'alkylation du phenylacetonitrile par l'epichlorhydrine en catalyse par transfert de phase solide-liquide assistee par les ultrasons. Le produit de cette alkylation, un cyanocyclopropane, conduit a une lactone, intermediaire reactionnel dans la synthese d'un anti-depresseur. Dans un premier temps, l'auteur s'interesse aux parametres influencant l'alkylation, en catalyse par transfert de phase solide-liquide, du phenylacetonitrile par le bromoethane, un agent alkylant largement etudie en liquide-liquide. Ensuite, l'auteur determine les conditions operatoires optimales et envisageables industriellement pour l'alkylation par l'epichlorhydrine dans le but de synthetiser la lactone. L'etude porte sur les effets de la nature de l'agent de transfert de phase, du solvant, de la puissance ultrasonore, de la nature de la base et d'autres parametres (mode d'addition des reactifs, impregnation de la base sur alumine,) ainsi, l'alkylation du phenylacetonitrile dans le dimethylsulfoxyde en presence d'hydroxyde de potassium et de polyethylene glycol a permis de reduire le temps de reaction et a conduit a une conversion superieure a 90% du substrat. La lactone desiree (isolee et cristallisee) est obtenue avec un rendement de l'ordre de 60%, comparable a celui obtenu industriellement avec l'amidure de sodium
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Ketchum, Douglas Robert. "Boron nitride: Nanotubes, composites, and potential catalyst support /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487946776020971.
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Poupin, Christophe. "Hydrogénation sélective ou compétitive de nitriles par voie catalytique." Poitiers, 2011. http://nuxeo.edel.univ-poitiers.fr/nuxeo/site/esupversions/518d1471-2f36-47d1-acac-5a37ac8f6936.
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Largement utilisées dans l'industrie sous forme de solvants, d'intermédiaires réactionnels ou bien synthétisées pour des usages pharmaceutiques, les amines sont indispensables à la société moderne. Afin d'optimiser les coûts de production, la voie catalytique consistant à hydrogéner des nitriles est de plus en plus développée. L'objectif de ce travail a consisté à approfondir les études en hydrogénation de l'acétonitrile en phase gazeuse. Les résultats montrent qu'un catalyseur sur support acide présente une meilleure activité mais un support basique oriente plus sélectivement vers les amines primaires. L'analyse FTIR en operando de l'adsorption et de l'hydrogénation catalytique de CH3C≡N a permis d'identifier un intermédiaire réactionnel : l'éthènimine (CH2=C=NH). L'hydrogénation de nitriles insaturés a ensuite été étudiée. Dans le cas de l'acrylonitrile, il n'a pas été possible de toujours se placer en régime cinétique. Toutefois, quelques résultats indiquent qu'un catalyseur bimétallique permet de former l'amine insaturée (allylamine). Pour le pentènenitrile, une étude comparative de Ru, Ni, Pt et Rh déposés sur alumine a montré que le Pt et le Rh étaient les plus actifs tandis que le Ni est le plus sélectif envers la pentylamine. L'ajout d'étain ou de germanium par greffage organométallique sur les catalyseurs déposés sur alumine permet d'augmenter l'activité du Pt et oriente la sélectivité vers l'amine tertiaire quel que soit l'ajout. Enfin, l'utilisation de différents supports (Al2O3, TiO2, CeO2, MgO) permet de conclure que l'absence de sites acides favorise la sélectivité en aminesWidely used in industry as solvents, reaction intermediates or synthesized for pharmaceutical uses, the amines are essential to modern society. To optimize the cost of production, consisting of catalytically hydrogenated nitrile is more developed. The aim of this study was to further study in the hydrogenation of acetonitrile in the gas phase. The results show that acid supported catalyst exhibits better activity, but a basic support is more selective toward the primary amines. FTIR analysis operando of adsorption and catalytic hydrogenation of CH3C≡N has identified a reaction intermediate: the éthènimine (CH2=C=NH). The hydrogenation of unsaturated nitriles was then studied. In the case of acrylonitrile, it was not always possible to place themselves in kinetic regime. However, some results indicate that a bimetallic catalyst is used to form the unsaturated amine (allylamine). For pentenenitrile, a comparative study of Ru, Ni, Pt and Rh deposited on alumina showed that the Pt and Rh were the most active while Ni is the most selective towards pentylamine. The addition of tin or germanium by grafting organometallic catalysts deposited on alumina increases the activity of Pt and direction selectivity to the tertiary amine, regardless of the addition. Finally, the use of different materials (Al2O3, TiO2, CeO2, MgO) leads to the conclusion that the absence of acid sites promotes the selectivity to amines
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Le, Fol Vogel Rachel. "Arylation de cyanures et de dérivés maloniques catalysée par les complexes du nickel." Montpellier 2, 2000. http://www.theses.fr/2000MON20154.
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Les nitriles aromatiques etant des composes couramment utilises en synthese organique, il est donc particulierement interessant de posseder une methode de synthese de ces composes, simple, facile d'acces, la plus generale possible et applicable industriellement. Nous avons etudie la reaction d'arylation de cyanures catalysee par les complexes du nickel a partir des aromatiques halogenes pour remplacer celle au cyanure de cuivre. Nous avons tout d'abord realise une etude approfondie de la reaction correspondante (cinetique, reversibilite, duree de vie du catalyseur, influence de l'eau) et de son optimisation (variation des parametres : temperature, ligand, co-catalyseur, cyanures). Une methode de cyanuration generale d'aromatiques halogenes a ete mise au point a 20\c, en presence de cyanure de potassium ou de cyanhydrine, catalysee par 5% de ni(pph 3) 3. Elle donne de tres bons rendements et de tres bonnes selectivites (80 a 99%) pour les aromatiques bromes et chlores substitues par des groupements electrodonneurs (ex : ome, ocome, sme) ou electroattracteurs (ex : cf 3, cn, come). La valorisation du p-trifluoromethylhalogenobenzene par des reactions de substitution nucleophile pour former des intermediaires fonctionnalises, strategiques dans les domaines agrochimique et pharmaceutique, est egalement un axe de recherche interessant. Nous avons etudie la reaction d'arylation de composes -difonctionnalises (malonate de diethyle, cyanoacetate d'ethyle, malonitrile). Une nouvelle reaction de substitution des halogenures d'aryles par le malonitrile, catalysee par ni(pph 3) 3 a 60\c, a ete developpee et appliquee a des substrats cibles, les p-trifluoromethylhalogenobenzenes brome et chlore, avec des rendements de 45 a 85% et de
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Ferrer, Vall-llosada Íngrid. "Development of new reusable materials based on Ru complexes with catalytic activity for olefin epoxidation and nitrile hydration." Doctoral thesis, Universitat de Girona, 2015. http://hdl.handle.net/10803/322785.
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In this thesis we present the synthesis and characterization of different types of ruthenium complexes containing N-donor ligands together with dmso, Cl and H2O ligands, along with their complete characterization through spectroscopic and electrochemical techniques. The complexes have been evaluated as catalysts for olefin epoxidation and nitrile hydration in homogeneous phase. On the other hand, taking into account the importance and advantages of the heterogeneous catalysis, we have carried out the immobilization of some of these complexes on silica-type supports and we have evaluated their catalytic activity, comparing them with the analogous homogeneous systems. It is outstanding the activity of complexes with dmso and pyrazolyl ligands in nitrile hydration to the amide products using water as solvent. The heterogeneous Ru-OH2 systems have been tested in olefin epoxidation and have been reused for several runs maintaining high values of selectivity for the epoxide.En aquesta tesi es presenta la síntesi de diferents tipus de complexos de ruteni que contenen lligands N-donadors en combinació amb lligands dmso, Cl i H2O, i la seva completa caracterització mitjançant tècniques espectroscòpiques i electroquímiques. Els complexos han estat avaluats com a catalitzadors en epoxidació d'olefines i hidròlisi de nitrils en fase homogènia. Per altra banda, tenint en compte la importància i els avantatges de la catàlisi heterogènia, s’ha dut a terme la immobilització d’alguns d’aquests complexos sobre suports tipus sílice i se n'ha avaluat l'activitat catalítica, comparant-los amb els anàlegs en fase homogènia. És destacable l'activitat dels complexos amb lligands dmso i pirazole en la hidròlisi de nitrils a amides en aigua com a dissolvent. Els sistemes Ru-OH2 heterogenis s'han avaluat en l'epoxidació d'olefines i s'han pogut reutilitzar durant diversos cicles mantenint alts valors de selectivitat per l'epòxid.
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Miclo, Yves. "Synthèse de systèmes polyhétérocycliques comportant un noyau pyridine par réaction de cyloaddition [2+2+2] catalysée par les métaux de transition." Paris 6, 2004. http://www.theses.fr/2004PA066421.
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Thamae, Mamothibe Amelia. "Metallophthalocyanine derivatives as catalysts for the detection of sulphur dioxide, cyanide, nitrite and amino acids." Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1004542.
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Electrocatalytic reduction and oxidation of nitrite using cobalt phthalocyanine derivatives was studied. The detection limit of 1 x 10⁻¹° mol dm⁻³ was achieved when these molecules were employed as catalysts for nitrite detection. The mechanisms for nitrite catalysis were proposed. The position of the peripheral substituents on cobalt porphyrazines (related to cobalt phthalocyanines) affected the catalytic activity of these complexes. The highest activity for nitrite reduction was observed on the cobalt(II) 2,3-tetramethyltetrapyridinoporphyrazine ([CoTm-2,3-tppa]⁴⁺), with cobalt phthalocyanine showing the lowest activity, and the cobalt(II) 3,4- tetramethyltetrapyridinoporphyrazine ([CoTm-3,4-tppa]⁴⁺), showing intermediate behaviour. A mixture of a negatively charged cobalt(II) tetrasulfophthalocyanine ([Co¹¹TSPc]⁴⁻) and a positively charged [CoTm-3,4-tppa]⁴⁺ showed better activity for nitrite reduction than did the individual components. Cobalt porphyrazines lowered the potentials for nitrite reduction in that peaking was observed, as opposed to cobalt phthalocyanine, where only the increase in currents was observed without peaking. Using the cobalt phthalocyanine derivatives, nitrite can be reduced to ammonia with high current efficiency. A glassy carbon electrode modified with [Co¹¹TSPc]⁴⁻ was employed for the determination of nitrite. Nitrate had an insignificant effect on nitrite oxidation on these modified electrodes. Electrocatalytic determination of S0₂ was studied as a function of pH at a glassy carbon electrode modified with iron(II) tetrasulfophthalocaynine. It was found that depending on pH, S0₂.xH₂0, HS0₃⁻ and/or SO₃²⁻ are the main compounds in solution and that these compounds behave differently at the electrode surface. Detection limits ranging from 4.0 ± 0.1 x 10⁻⁵ to 7.5 ± 0.1 x 10⁻⁵ mol dm⁻³ depending on pH were observed. Similar results were obtained when cobalt(II) tetrasulfophthalocaynine was employed for S0₂ catalysis under the same experimental conditions. Cysteine and histidine determination using oxidation currents was performed on glassy carbon electrodes modified with [CoTm-3,4-tppa]⁴⁺ (represented as [CoTm-3,4-tppa]⁴⁺-GCE) in pH 7 Tris buffer. The detection limit of 1.0 x 10⁻⁵ mol dm⁻³ for cysteine and 2.24 x 10⁻⁷ mol dm⁻³ for histidine were obtained. Cyanide can be detected down to 1 x 10⁻¹¹ mol dm⁻³ using [CoTm-3,4-tppa]⁴⁺-GCE in pH 10.8 buffer. Cyanide and S0₂ coordinate to the [CoTSPc]⁴⁻ species. The coordination is accompanied by oxidation of the central Co(II) metal, forming a [Co¹¹¹CoTSPc]³⁻ species. The rate constants for cyanide coordination to the [Co¹¹TSPc]⁴⁻ complex are larger than those reported for the coordination of cyanide to FePc and RuPc complexes in non-aqueous media. Autoreduction of [Co¹¹Tmtppa]⁴⁺ occurred in the presence of either histidine or cysteine, with the formation of metal reduced species, [Co¹Tmtppa(-2)]³⁺. Nitric oxide and nitrite coordinate to the [Co¹¹Tmtppa]⁴⁺ species, without auto-reduction of this species, which was observed for cysteine or histidine. The use of [Co¹¹TSPc]⁴ resulted in improved rate of interaction with nitrite when compared to the [Co¹¹Tmtppa]⁴⁺ species.
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Desai, Alpesh I. "Hydrazide, diazenide and nitride cores as spectator ligands for olefin metathesis catalysts." Thesis, University of Essex, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336880.
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Zhang, Liping. "Hydrodenitrogenation of organonitrogen compounds over nickel-molybdenum sulfide and Molybdenum nitride catalysts /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487942739805674.
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Fager, Diana Catherine. "Catalytic Enantioselective Additions of Allyl Moieties to α-Halomethyl Ketones, Trifluoromethyl Substituted NH-Ketimines, and Nitriles:." Thesis, Boston College, 2020. http://hdl.handle.net/2345/bc-ir:108931.
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Thesis advisor: Amir H. HoveydaHomoallylic alcohols and amines are commonly used building blocks for synthesis of biologically active molecules, yet a survey of the methods for their synthesis reveals a plague of limitations. Notably, the use of toxic reagents (Cr-, Mn-, and Sn-containing), precious metal catalysts (Ir- and In-based), non-ambient reaction temperatures (–78 to 140 °C), and extended reaction times (up to 240 hours), limit application on larger scale. The protection/deprotection sequences required to install directing/activating groups for reaction efficiency and enantioselectivity not only add synthetic steps but the conditions required for removal of such entities are not amenable to more complex and sensitive molecules. The development of catalytic enantioselective methods for addition of allyl moieties to readily available substrates including halomethyl ketones, trifluoromethyl-substituted ketimines, and nitriles have been developed. In the first two cases, an aminophenol-based boryl catalyst is utilized for enantioselective additions of allyl moieties through transition states controlled by either electrostatic attraction between a C–X bond and the catalyst’s ammonium moiety or minimization of steric and dipolar repulsion. In the latter, multicomponent additions to nitriles have been developed for synthesis of cyclic amines. In all cases, application is demonstrated through synthesis of otherwise difficult-to-access derivatives or biologically active molecules
Thesis (PhD) — Boston College, 2020
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Kerkeni, Samy. "Etude par méthodes électrochimiques de la réduction des nitrates et des nitrites en phase aqueuse." Poitiers, 2003. http://www.theses.fr/2003POIT2251.
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L'objectif de ce travail est d'étudier, d'un point de vue fondamental, les deux aspects que sont l'activité et la sélectivité catalytiques en réduction des nitrates et des nitrites, en présence de catalyseurs au Cuads/Pt (non supportés) préparés et caractérisés par emploi de techniques électrochimiques. Lors de l'hydrogénation, le potentiel du catalyseur peut être établi spontanément en présence des réactifs ou contrôlé au moyen d'un potentiostat. Ces trois modes de contrôle du potentiel du catalyseur ont été employés dans ce travail. Différents paramètres ont été étudiés : le taux de recouvrement en cuivre, la nature des anions et des cations présents dans la solution, le pH de la solution, la concentration des nitrates ou des nitrites, la pression partielle d'hydrogène et le potentiel du catalyseurThe objective of this work is to study, from a fundamental point of view, the two aspects that are catalytic activity and selectivity in reduction of nitrates and nitrites, in the presence of (not supported) catalysts Cuads/Pt prepared and characterized by use of electrochemical techniques. During the hydrogenation, the potential of the catalyst can be established spontaneously in the presence of reactants or controlled by means of a potentiostat. These three modes of control of the catalyst potential were used in this work. Various parameters were studied : copper coverage, nature of anions and cations present in the solution, pH of the solution, concentration of nitrates or nitrites, partial pressure of hydrogen and potential of the catalyst
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Fox, Brandy R. 1981. "Investigations into the Oxidative Desulfurization Activity in a Film-Shear Reactor, the Source of Enhanced Reactivity, and Other Potential Applications." Thesis, University of Oregon, 2011. http://hdl.handle.net/1794/11529.
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xviii, 242 p. : ill. (some col.)Fuel purification is an extremely active area of research in today's green world. Specifically, desulfurization of fuels is an important area of research for two reasons. First, any sulfur present in fuels generates SOx pollutants that are hazardous to human health and also contribute to acid rain. Secondly, even trace sulfur contaminants prohibit the use of fuel streams in fuel cells. However, achieving near-zero sulfur levels with existing technology is impractical. The work in this thesis investigates a new process for the removal of sulfur from fuel streams using a film-shear reactor (based on a process known as oxidative desulfurization), and goes on to investigate the mode of activation for the process within the reactor through a study of the reactor conditions. Additionally, other applications of the film-shear reactor, including mechanical activation of molecules and controlled nanoparticle synthesis are explored. Chapter I outlines the current status of oxidative desulfurization research, highlighting the strengths of the method, innovative approaches and drawbacks to the various approaches. Chapters II and III go on to discuss the enhancement of the process in the film-shear reactor using model fuels and a variety of substrates. This method was found to significantly enhance the oxidative desulfurization process, reducing both the time and temperature required to achieve considerable sulfur removal. Levels of desulfurization that require hours at elevated temperatures by conventional stirring methods were obtainable on the scale of seconds at or below room temperature. Chapter IV offers investigations into the conditions within the film-shear reactor, and also presents studies of the ability of the high shear rates obtained in the reactor to mechanically activate molecules. Chapter V extends the applicability of the film-shear reactor to nanoparticle synthesis through investigation of two titania synthesis methods utilizing the film-shear reactor. Appendices A and B offer supplementary information to enhance the studies presented in Chapters II and III, while Appendices C, D, and E highlight work done investigating the ability of platinum complexes to hydrate nitriles and cyanohydrins. This dissertation includes previously published and unpublished co-authored material.
Committee in charge: Victoria J. DeRose, Chairperson; David R. Tyler, Advisor; Kenneth M. Doxsee, Member; Catherine J. Page, Member; Mark H. Reed, Outside Member
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Brechot, Philippe. "Oxycarbonylation des olefines en presence de nitrites d'alkyle catalysee par les complexes du palladium." Paris 6, 1988. http://www.theses.fr/1988PA066107.
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Pollard, Ashleigh J. J. "Silica and boron nitride supported molybdenum and vanadium oxide catalysts for alkane oxidation." Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55535/.
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A range of silica supported molybdenum catalysts and vanadium catalysts have been prepared and tested for alkane oxidation. Further vanadium catalysts supported on boron nitride have also been prepared and tested for alkane oxidation. The silica supported molybdenum oxide catalysts demonstrated appreciable activity for propane total oxidation to carbon oxides with some trace acrolein. The silica supported vanadium catalysts were also active for propane oxidation, and although the major product was carbon dioxide, higher selectivity to acrolein was observed when compared to the silica supported molybdenum catalysts. The use of boron nitride as a support significantly increased the selectivity towards acrolein and other selective oxidation products like acrylic acid. These results lead to the catalysts being tested for propene oxidation, which produced similar results that showed the boron nitride supported vanadium catalysts were more selective than the silica supported catalysts for acrolein. Further tests were carried out on methane and ethane, which produced mostly carbon oxides as a result. The effect of co-feeding water was also tested when performing propane oxidation with the presence of water effecting the selectivity and activity of the catalysts. Some catalyst's activity was suppressed with increased selectivity to acrolein and other catalysts activity was promoted which led to total oxidation to carbon oxides. This study aim is to compare and contrast the different catalysts produced and give evidence about how the use and development of a hydrophobic support may lead to better catalyst design in the future.
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Garg, Aaron R. "Transition metal carbide and nitride nanoparticles with Noble metal shells as enhanced catalysts." Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/121890.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2018Cataloged from PDF version of thesis. Page 157 blank. Vita.
Includes bibliographical references (pages 137-153).
Core-shell nanostructures represent a promising and versatile design platform for enhancing the performance of noble metal catalysts while reducing the cost. Early transition metal carbides (TMCs) and nitrides (TMNs) have been identified as ideal core materials for supporting noble metal shells owing to their earth-abundance, thermal and chemical stability, electrical conductivity, and their ability to bind strongly to noble metals while still being immiscible with them. Unfortunately, the formation of surface oxides or carbon on TMCs and TMNs presents a difficult synthetic challenge for the deposition of atomically thin, uniform noble metal layers. Recent advances have enabled the synthesis of TMC core nanoparticles with noble metal shells (denoted as NM/TMC), although applicability toward TMN cores has not been previously demonstrated. Furthermore, the complete properties of these unique materials are still unknown.
This thesis conducts a detailed investigation of the synthesis, characterization, and catalytic performance of NM/TMC and NM/TMN core-shell nanoparticles to provide a comprehensive understanding of their material properties and the underlying phenomena. First, in-situ studies yielded insight into the mechanism behind the high temperature self-assembly of NM/TMC particles, indicating the presence of a metallic alloy phase preceding the formation of the core-shell structure upon insertion of carbon into the lattice. Next, the synthesis of NM/TMN nanoparticles was demonstrated via nitridation of a parent NM/TMC, and the structural and electronic properties of both core-shell materials were examined through in-situ X-ray absorption spectroscopy (XAS). The analysis revealed significant alterations to the electronic structure of the noble metal shell due to bonding interactions with the TMC and TMN cores, which led to weakened adsorbate binding energies.
Finally, the materials displayed improved performance for the oxygen reduction reaction (ORR), a critical challenge for fuel cell technologies. Notably, particles with complete, uniform shells exhibited unprecedented stability during electrochemical ageing at highly oxidizing conditions, highlighting the great potential of core-shell architectures with earth-abundant TMC and TMN cores for future ORR applications. Overall, this work will provide new opportunities toward the design of enhanced noble metal catalysts and enable further optimization of their performance.
by Aaron R. Garg.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Chemical Engineering
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Sam, Katharine A. "Investigating the mechanisms of cytochrome cd₁ catalysed reduction of nitrite and oxygen." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670119.
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Perret, Noemie. "New catalyst formulations based on gold and molybdenum nitrides and carbides : application in selective hydrogenation." Thesis, Heriot-Watt University, 2012. http://hdl.handle.net/10399/2657.
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The development of selective heterogeneous catalytic systems is of fundamental importance for the realisation of sustainable green chemical processes. In this thesis, the hydrogenation of nitroarene, aldehyde and carboxylic acid compounds is examined in continuous gas phase operation, for the synthesis of a target functionalised aromatic amine and alcohol. Novel catalysts based on Mo nitride, carbide and supported Au have been synthesised and subjected to an array of complementary characterisation measurements that provide catalyst structure/performance correlations with detailed kinetic and mechanistic analysis. The use of Mo2N and Mo2C as catalysts served to promote the selective hydrogenation of nitrobenzene to aniline and p-chloronitrobenzene to p-chloroaniline where the incorporation of nano-scale Au increased reaction rate. Activity has been correlated to hydrogen adsorption/release capacity, which shows a dependence on the degree of nitridation and crystallographic structure. In contrast, hydrogenation of benzaldehyde is limited by C=O activation, which is facilitated by the Mo component. Alumina supported Au has exhibited 100% selectivity in the hydrogenation of benzaldehyde and 4-nitrobenzaldehyde to the target alcohol, where Au particle size and surface Lewis acidity play crucial roles. The hydrogenation of benzoic acid over Au supported on a CeO2-ZrO2 mixed oxide has shown promising results with the possibility of a one step transformation to the alcohol. The results presented in this thesis establish feasible catalytic routes to high value amines and alcohols where critical process optimisation is demonstrated in terms of catalyst composition/surface structure and reaction conditions.
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La, Fontaine Camille. "Hydrogénation catalytique des nitriles : recherche et développement de catalyseurs sélectifs à base de métaux nobles." Poitiers, 2007. http://www.theses.fr/2007POIT2285.
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Largement utilisées dans l’industrie sous forme de solvants, d’intermédiaires réactionnels ou bien synthétisées pour des usages pharmaceutiques, les amines sont indispensables à la société moderne. Une voie de synthèse est l’hydrogénation catalytique de nitriles mais les catalyseurs hétérogènes développés, souvent à base de nickel, s’avèrent inappropriés pour l���hydrogénation de molécules complexes. L'objectif de ce travail a consisté tout d’abord à réaliser une étude comparative de Ru, Ni, Pd, Pt et Rh déposés sur alumine en hydrogénation de l’acétonitrile en phase gazeuse. Les métaux les plus actifs sont Pt et Rh. Quelle que soit la taille des particules métalliques, Pt conduit à la formation des amines primaire et tertiaire, alors que sur Rh un mélange des amines secondaire et tertiaire est obtenu. Les catalyseurs subissent une désactivation importante au cours de la réaction, due principalement à l’empoisonnement des sites actifs par des espèces fortement adsorbées. Une régénération est alors possible par simple traitement thermique sous atmosphère inerte. Différentes pistes ont ensuite été explorées pour l’optimisation des catalyseurs et la compréhension des mécanismes de la réaction. L’ajout de Sn par greffage organométallique permet de stabiliser l’activité de Rh en accord avec un effet électrodonneur. L’emploi de supports tels que CeO2 ou MgO permet d’améliorer la sélectivité en amine primaire, tant pour Rh que pour Pt. Les propriétés d’oxydoréduction de CeO2 modifient l’adsorption et la désorption des espèces et l’absence de sites acides à la surface de MgO inhibe les réactions de condensation. Un mécanisme bifonctionnel de la réaction est donc confirméWidely used in industry as solvents, reaction intermediates or synthesized for pharmaceutical uses, amines are essential in modern society. A way of synthesis is the catalytic hydrogenation of nitriles but the heterogeneous catalysts developed, often based on nickel, are inappropriate for the hydrogenation of complex molecules. The main objective of this work consisted firstly in carrying out a comparative study of Ru, Ni, Pd, Pt and Rh supported over alumina for the gas phase hydrogenation of acetonitrile. The most active metals are Pt and Rh. Whatever the particle size, Pt leads to the formation of primary and tertiary amines, while over Rh a mixture of secondary and tertiary amines is obtained. During the reaction, the catalysts are sensitive to deactivation mainly due to strongly adsorbed species poisoning active sites. Regeneration can be achieved by heating up the catalyst in inert atmosphere. Further investigations were then performed to optimize the catalysts and to understand the reaction mechanisms. Adding Sn by organometallic grafting stabilizes Rh activity in agreement with an electronic effect of Sn, acting as electron donor. The use of supports such as CeO2 or MgO improves the selectivity towards the primary amine, over either Rh or Pt. The redox properties of CeO2 modify products adsorption and desorption and the absence of acid sites on MgO surface inhibits condensation reactions. So a bifunctional mechanism is confirmed
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Lucy, Toby E. "Synthesis, characterization and reactivity of tungsten oxynitride." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-11012008-063455/.
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Sayão, Fabiana Avolio. "Modificação de eletrodos de carbono vítreo e nanotubos de Ti/TiO2 com aspirinato de cobre(II) para detecção eletroquímica e redução fotoeletrocatalítica de íons nitrito /." Araraquara, 2016. http://hdl.handle.net/11449/133992.
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Orientador: Maria Valnice Boldrin ZanoniBanca: Regina Celia Galvão Frem
Banca: Lúcio Cesar de Almeida
Resumo: O presente trabalho ilustra duas vertentes para modificação de eletrodo com complexo as pirinato de cobre (II), [(Cu) 2 (Asp) 4 ]. A primeira baseou - se no desenvolvimento de um sensor eletroquímico para detecção de íons nitrito em soluções aquosas. I nicialmente foi estudado o comportamento eletroquímico por voltametria cíclica, sobre eletrodo de carbono vítreo em tampão B - R (0,1 mol L - 1 ) . Nesta condição do estudo, verific ou - se que o complexo apresenta comportamento irreversível e controlado por difusão . Em seguida, imobilizou - se o [( Cu ) 2 (Asp) 4 ] por ciclagens sucessivas sobre a superfície do eletrodo de carbono vítreo, observandoa capacida de eletrodo modificado de tectar os íons nitrito em solução aquosa cerca de 57% melhor que o eletrodo de carbono vítreo sem modificação . O eletrodo de carbono vítreo modificado aplicado para analisar uma amostra comercial de sal de cura ( que contem 5 % (m/m ) de NO 2 - ), diluída em tampão B - R na concentração de 1,0 g L - 1 . O método utilizado foi o adição de padrão, resultando em uma concentração de 0,059 g L - 1 de íons nitrito, obtendo erro de 18%. Indicando boa performanc e do ECV modificado com [(Cu) 2 (Asp) 4 ] para sensor eletroquímico de NO 2 - . A segunda vertente fundamenta - se na modificação de eletrodos de nanotubos de Ti/TiO 2 com [ ( Cu ) 2 (Asp) 4 ] para aplicação de fotoc átodo na redução de NO 2 - . A investigação da redução de íons nitrito por fotoeletrocatálise revelou a melhor condição em 15 mmol L - 1 de NaCl, como eletrólito de suporte, sob potencial de - 0,6 V em pH original da solução sobre o eletrodo modificado com [ ( Cu ) 2 (Asp) 4 ] . A redução de 5,0 mg L - 1 de nitrito nestas condições resultou na redução total em apenas 6 minutos formando 47% de íons amônio e 53% de nitrogênio dissolvidos como outras espécies, sem a presença de íons nitrato....
Abstract: ABSTRACT This paper illustrates two aspects to electrode modified with aspirinat o complex of copper (II), [(Cu) 2 (Asp) 4 ]. The first was based on the development of an electrochemical sensor for the detection of nitrite ions in aqueous solutions. Initially we studied the electrochemical behavior by cyclic voltammetry on glassy c arbon electrode in B - R buffer (0, 1mol L - 1 ). In this condition the study, it was found that irreversible complex features and behavior controlled by di ffusion. Then the [(Cu) 2 (Asp) 4 ] By cycling successive on the surface of the glassy carbon electrode was immobilized by observing the electrode capacity modified detecting the nitrite ions in aqueous solution about 57% better than the electrode glassy carbon without modification. The modified glassy carbon electrode applied to analyze a commercial sample of curing salt (containing 5% (m/m) of NO 2 - ), diluted in BR buffer at a co ncentration of 1.0 g L - 1 . The method used was the added pattern, resulting in a concentration of 0.059 g L - 1 of nitrite ions, obtaining 18% error. Indicating good p erformance of glassy c arbon electrode modified [(Cu) 2 (Asp) 4 ] for electrochemical sensor NO 2 - . The second part is based on the modification of nanotubes electrodes of Ti/ TiO 2 with [(Cu) 2 (Asp) 4 ] for application of photocathode in reducing NO 2 - . The investigation of reducing nitrite ions per photoelectrocatalysis showed the best condition in 15 mmol L - 1 NaCl as supporting electrolyte under potential - 0.6 V at the original pH of the solution on the electrode modified with [(Cu) 2 (Asp) 4 ]. The reduction 5.0 mg L + of nitrite under these conditions resulted in a complete reduction in only 6 minutes to form ammonium ions 47% and 53% of nitrogen and other dissolved species without the presence of nitrate ions. Modification of tubular nanostructures Ti /TiO 2 with [(Cu) 2 (Asp) 4 ] performed better in...
Mestre
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Camurlu, Hasan Erdem. "Carbothermic Production Of Hexagonal Boron Nitride." Phd thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607808/index.pdf.
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Formation of hexagonal boron nitride (h-BN) by carbothermic reduction of B2O3 under nitrogen atmosphere at 1500oC was investigated. Reaction products were subjected to powder X-ray diffraction analysis, chemical analysis and were examined by SEM. B4C was found to exist in the reaction products of the experiments in which h-BN formation was not complete. One of the aims of this study was to investigate the role of B4C in the carbothermic production of h-BN. For this purpose, conversion reaction of B4C into h-BN was studied. B4C used in these experiments was produced in the same conditions that h-BN was formed, but under argon atmosphere. It was found that formation of h-BN from B4C&ndashB2O3 mixtures was slower than activated C&ndash
B2O3 mixtures. It was concluded that B4C is not a necessary intermediate product in the carbothermic production of h-BN. Some additives are known to catalytically affect the h-BN formation. The second aim of this study was to examine the catalytic effect of some alkaline earth metal oxides and carbonates, some transition metal oxides and cupric nitrate. It was found that addition of 10wt% CaCO3 into the B2O3+C mixture was optimum for increasing the rate and yield of h-BN formation and decreasing the B4C amount in the products and that the reaction was complete in 2 hours. CaCO3 was observed to be effective in increasing the rate and grain size of the formed h-BN. Addition of cupric nitrate together with CaCO3 provided a further increase in the size of the h-BN grains.
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Pedoussaut, Michel. "Catalyse par transfert de phase, solide-liquide, sans solvant rajouté optimisation de la synthèse de nitriles : préparation et hydrolyse d'esters encombrés /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37617412c.
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Pedoussaut, Michel. "Catalyse par transfert de phase, solide-liquide, sans solvant rajouté : optimisation de la synthèse de nitriles : préparation et hydrolyse d'esters encombrés." Paris 11, 1988. http://www.theses.fr/1988PA112041.
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Ce travail a montré que dans des conditions de Catalyse par Transfert de Phase solide-liquide, sans solvant rajouté, il était possible de réaliser dans de bonnes conditions expérimentales la synthèse de nitriles, par action de KCN (ou de NaCN) sur des halogénures d'aryles ou d'alkyles, par exemple. Le rôle de l'eau a été étudié, ainsi que son remplacement par des additifs divers. Des essais de corrélation entre rendements observés en nitrile et paramètre physicochimique des additifs ont mis en évidence le rôle des paramètres de solubilité de HANSEN. Des études spectroscopiques (RMN du proton à 250 MHz - IR TF a réflexion diffuse) ont permis de mettre en évidence des interactions entre KCN, additif et agent de transfert. Un diagramme réactionnel est proposé et l'utilisation d'un plan d'expérience a permis d'optimiser la synthèse de nonanenitrile à partir de chlorure d'octyle et de KCN. Dans nos conditions opératoires la saponification d'esters mésitoïques, réaction considérée comme très difficile, se fait avec de très bons rendements, ainsi que la préparation d'esters mésitoïques par alkylation d'acide mésitoïque.
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Tadros, Ziad. "Hydratation énantiosélective d'}a-aminonitriles en pré̄sence de composés carbonylés chirauxImmobilisation d'enzymes sur support chimiquement réactif de type N-polyacryloyl-4-pipéridone." Montpellier 2, 1990. http://www.theses.fr/1990MON20248.
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Dans la premiere partie de ce travail, l'hydratation enantioselective des alpha-aminonitriles en alpha-aminoamides est etudiee en milieu aqueux basique en presence de catalyseurs cetoniques chiraux. La synthese et l'etude de tels catalyseurs sont decrites apres avoir defini les criteres de choix du compose carbonyle chiral. Cette etude a permis de cerner les parametres importants de cette reaction d'hydratation a savoir: la teneur et la nature du cosolvant utilise, la temperature, la concentration en oh# et en catalyseur. L'activite catalytique ainsi que l'enantioselectivite de ces catalyseurs sont evaluees. Dans la deuxieme partie, apres avoir analyse les conditions d'immobilisation de la pronase et principalement le mode de polymerisation de l'acryloyl-4-piperidone, en masse et en suspension, la compatibilite des conditions operatoires entre le support (catalyseur chimique d'hydratation de l'alpha-aminonitrile) et la pronase (catalyseur biochimique d'hydrolyse de l'alpha-aminoamide) est developpee. Il est montre qu'a ph 11 et en presence de tampon phosphate, la pronase peut se comporter comme une pseudonitrilase l enantioselective, lorsqu'elle est immobilisee sur ce support. Ce mode de polymerisation est etendu a l'immobilisation d'autres enzymes, en particulier l'urease et la glucose oxydase, en insistant sur le caractere chimiquement reactif du support dans l'activite et la stabilite de ces enzymes
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Diebl, Bernd Eduard [Verfasser]. "Synthesis and Characterization of Nitrile ligated Transition Metal Complexes bearing WCAs as Catalysts for the Homopolymerization of Isobutylene / Bernd E. Diebl." München : Verlag Dr. Hut, 2010. http://d-nb.info/1009095560/34.
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Carnevale, Santino D. "Catalyst-free III-nitride Nanowires by Plasma-assisted Molecular Beam Epitaxy: Growth, Characterization, and Applications." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1374066626.
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