Thèses sur le sujet « Catalasi »
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Guo, Chris. « Alkane Oxidation Catalysis by Homogeneous and Heterogeneous Catalyst ». Thesis, The University of Sydney, 2005. http://hdl.handle.net/2123/622.
Texte intégralGuo, Chris. « Alkane Oxidation Catalysis by Homogeneous and Heterogeneous Catalyst ». University of Sydney. Chemistry, 2005. http://hdl.handle.net/2123/622.
Texte intégralJohnston, Eric. « New Tools for Green Catalysis : Studies on a Biomimetic Hybrid Catalyst and a Novel Nanopalladium Catalyst ». Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-65079.
Texte intégralAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Submitted. Paper 5: Manuscript.
Markovits, Iulius [Verfasser]. « Ionic Liquids in Oxidation Catalysis : from Solvent to Catalyst / Iulius Markovits ». München : Verlag Dr. Hut, 2017. http://d-nb.info/1126297577/34.
Texte intégralFord, David Dearborn. « The Role of Catalyst-Catalyst Interactions in Asymmetric Catalysis with (salen)Co(III) Complexes and H-Bond Donors ». Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11154.
Texte intégralChemistry and Chemical Biology
Montalat, Buscató Pere. « Lexicografia catalana siscentista : el Gazophylacium Catalano-Latinum, de Joan Lacavalleria i Dulac ». Doctoral thesis, Universitat de Girona, 2020. http://hdl.handle.net/10803/673089.
Texte intégralAquesta tesi està dedicada a l’estudi i a l’edició parcial del Gazophylacium Catalano-Latinum, de Joan Lacavalleria i Dulac, un tresor lexicogràfic català-llatí publicat l’any 1696 a Barcelona que constitueix l’aplec de lèxic català més extens i exhaustiu de la dissetena centúria. El treball s’enceta amb una recerca històrica a l’entorn dels membres de la família Lacavalleria i de la seva època. En segon lloc, s’identifiquen les fonts emprades per Lacavalleria i s’estudia fins a quin punt les va seguir en l’elaboració del Gazophylacium; en tercer lloc, s’analitzen els elements que configuren l’estructura del diccionari i la naturalesa del lèxic que conté; en quart lloc, es tracta de la recepció de l’obra i de la seva influència sobre la lexicografia i la lingüística catalana posterior; en cinquè lloc, es reporten els criteris adoptats per a l’establiment dels textos d’aquest diccionari que edito críticament i, a l’últim, s’ofereixen els textos editats
Programa de Doctorat en Ciències Humanes, del Patrimoni i de la Cultura
Sierra, salazar Andrés Felipe. « Waterborne catalytic materials with original design ». Thesis, Montpellier, Ecole nationale supérieure de chimie, 2017. http://www.theses.fr/2017ENCM0014/document.
Texte intégralLa catalyse est l'un des piliers pour le développement de procédés durables, car elle permet d'utiliser moins de ressources en accélérant les réactions chimiques. Afin de fournir des catalyseurs plus performants, cette étude propose une nouvelle méthode de préparation de catalyseurs pour contrôler la distribution de nanoparticules (NPs) métalliques au sein des catalyseurs hiérarchiquement poreux (méso et macro) en combinant la synthèse de latex, la réduction sonochimique et le procédé sol-gel. La première étape est la synthèse d'une empreinte porogène de billes de polystyrène (latex) obtenues par polymérisation en émulsion aqueuse. La deuxième étape est la synthèse et le dépôt de NPs de métaux nobles sur la surface des billes de polymère par voie sonochimique dans l’eau. La troisième étape est la synthèse du support catalytique par un procédé sol-gel en milieu aqueux en utilisant le latex décoré et l’orthosilicate de tétraéthyle (TEOS) dans des conditions contrôlées pour moduler la porosité finale de la matrice de silice (mésoporeuse). Toutes les étapes de cette approche sont effectuées dans l'eau, ce qui limite les impacts environnementaux de la préparation du catalyseur. L'élimination du porogène (latex) par calcination génère les macropores. Le matériau résultant possède alors une morphologie inédite pour un catalyseur, avec des macropores fonctionnalisés par des NPs métalliques, dans une matrice de silice mésoporeuse. Ainsi, il a été possible de synthétiser un latex monodisperse de polystyrène (~130 nm), lequel a été décoré avec des NPs de Pt (~2.3 nm) par réduction sonochimique. Le matériau final de silice a présenté des mésopores (2-15 nm) reliant les macropores (110-400 nm) contenant les NPs de Pt. Il a été possible d'obtenir des surfaces spécifiques et des volumes poreux totaux de 615 m2/g et 0,74 cm3/g, respectivement. Dans un premier cas d'étude, des catalyseurs de Pt/SiO2 à porosité hiérarchique ont été évalués dans l'hydrogénation sélective du p-chloronitrobenzene (p-CNB) pour produire la p-chloroaniline. Ils ont présenté des activités catalytiques allant jusqu'à 91,7 ± 2,9 molCNB/(min molPt) et des sélectivités jusqu'à 100 ± 2% à 80% de conversion, par rapport à 47,7 ± 2,9 molCNB/(min molPt) et 91 ± 2%, respectivement, obtenus dans les mêmes conditions avec un catalyseur commercial. Dans un deuxième cas d'étude, des catalyseurs à base de Pd, Pd-Pt et Pd-CeO2 supportés sur de la silice à porosité hiérarchique ont été préparés et testés dans la synthèse directe du peroxyde d'hydrogène. La meilleure productivité a été obtenue avec le catalyseur bimétallique Pd-Pt avec 32500 molH2O2/(h molmétal) en batch, et la meilleure sélectivité a été obtenue avec le catalyseur Pd-CeO2/SiO2 (63 ± 2%) en semi-continu. En résumé, cette thèse propose une nouvelle méthode de préparation dans l’eau de matériaux fonctionnels à porosité hiérarchique en combinant la synthèse de latex, la réduction sonochimique et le procédé sol-gel. Il a été démontré que cette technique de préparation fournit une boîte à outils très puissante et polyvalente pour la préparation et l'optimisation des catalyseurs. Des perspectives pour améliorer davantage les morphologies et la distribution contrôlée des sites actifs sont également proposées
Chenneberg, Ludwig. « Nouvelles avancées en catalyse photoredox : applications en chimie radicalaire de synthèse et en catalyse duale ». Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066305/document.
Texte intégralVisible-light photoredox catalysis has emerged as a very powerful strategy to generate radical species replacing more and more tin-mediated or stoichiometric redox methodologies. The main objective of the research described in this Ph. D. thesis is to develop new synthetic methodologies in radical and organometallic chemistry, and merge them in a dual catalysis process for the preparation of elaborated molecular building blocks. In a first study, we report a photocatalytic alternative of Barton-McCombie deoxygenation based on a visible-light photoreduction of O-thiocarbamates derived from secondary and tertiary alcohols. A mechanistic investigation is presented based on fluorescence quenching and cyclic voltammetry experiments. In a second study, a challenging method of generation of unstabilized alkyl radicals by photooxidation of borate salts or hypervalent silicon species is reported. These radicals are trapped by free radical scavengers or engaged in a photoredox/nickel dual catalysis
Verdaguer, i. Turró Miquel. « Jaume Serra Hunter i la teoria de la cultura en el Noucentisme ». Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/32058.
Texte intégralLa filosofia catalana moderna i contemporània ha estat tradicionalment molt poc estudiada tant per motius estrictament històrics i polítics com per la mateixa convicció més o menys compartida que, especialment si se la compara amb la literatura i, fins i tot, amb la historiografia, es tracta d'una aportació molt menor i de segon ordre. Uns dels personatges importants del món de la filosofia catalana ha estat el polifacètic i carismàtic Jaume Serra Hunter, al qual la història no ha fet justícia. Com tants altres, va ser un represaliat del franquisme, declarat fora de la llei i perseguit i exiliat, primer a França i després a Mèxic. Aquest treball d'investigació vol donar a conèixer la seva persona i la seva enorme tasca com a polític. Però, per damunt de tot, vull transmetre el seu profund amor per la cultura i la defensa aferrissada que en va fer, especialment de la catalana, seguint en fil discursiu de la seva obra filosòfica. Vull reivindicar la figura de Serra Hunter i la seva lluita per la cohesió cultural a través de la seva filosofia, fent-la arribar a tothom. Vull demostrar com va treballar, en una època de forta crisi de la societat, de la cultura i de l'educació, per sortir de la crisi amb la filosofia com a guia. Serra Hunter va viure una època de moltes dificultats per a la filosofia. Però ell volia fer arribar la cultura a tothom. La seva, és una filosofia, que amb els temes que tracta pot ser, fins i tot una mena d'avançada al món i a alguns dels problemes que aquest té avui en dia. Segons ell, la filosofia hauria de ser més humana i més viva i estar present en tots els diversos plans d'estudis de qualsevol pla educatiu.
Han, Xu. « Development of innovative methodologies in phosphine organocatalysis and enantioselective gold(I)-catalysis ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS568.
Texte intégralPhosphines play a major role in modern organic chemistry. In the field of catalysis, organophosphorus derivatives can be applied as catalysts in numerous transformations by itself, as organocatalysts, or as ligands in organometallic catalysis. This thesis focused on the application of phosphines both in phosphine organocatalysis and in asymmetric gold(I) catalysis. In the organophosphorus catalysis part, we have developed a phosphine-catalyzed Michael addition/Wittig reaction by using a well-chosen cyclic phosphine catalyst. In this process, silane was used as reducing agent to selectively reduce in situ the phosphine oxide. A series of highly functionalized 1,2-dihydroquinolines were prepared. Besides, a new olefination process was discovered for the synthesis of succinate derivatives. Detailed mechanism research was carried out with H/D exchange experiments. In the asymmetric gold(I) catalysis part, we have developed two new methodologies based on cyclization reactions of 1,n-enyne substrates. A 1,5-enyne cyclization/nucleophilic addition reaction was first developed with an acyclic TADDOL-derived phosphoramidite-Au(I) complex. Twenty examples were carried out with good to excellent yields and up to 94% enantiomeric excess. For the 1,6-enyne cyclization/intramolecular nucleophilic addition sequence, we have synthesized a range of racemic tetracyclic and pentacyclic compounds in high yields. The enantioselective version of this transformation was carried out successfully with both high reactivity and enantioselectivity
Chen, Si. « New approach to aqueous biphasic catalysis through catalyst confinement in nanoscopic core-shell polymers ». Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30163/document.
Texte intégralThe catalytic processes are at the heart of chemical industry. Modern chemical industry, under pressure of stricter regulations and societal concern, is faced with the need to improve efficiency and cleaner production processes and catalysis is one the major keys to green chemical technology. Catalysts recovery is necessary from an economic and environmental point of view when it makes use of expensive and / or toxic metals. The aim of this thesis is based on an innovative approach related to micellar catalyst but in which the catalyst is covalent linked to the hydrophobic core of well-defined unimolecular, core-cross-linked micelles. The synthetic protocol is based on a convergent method via RAFT-mediated one-pot aqueous emulsion polymerization. The efficiency of these unimolecular micelles as catalytic nanoreactors has been shown using the industrially relevant hydroformylation of 1-octene, in order to provide a proof of principle, as a test reaction yielding turnover frequencies and l/b ratio comparable to those of related homogeneous systems. However, the catalyst phase could be easily separated from the organic product phase and recycled. A remarkable protecting effect of the active catalyst by the polymer scaffold has also been demonstrated. The absence of the coagulation at the end of reaction is evidence that these new objects function as micelles while eliminating the disadvantages of micellar catalysis such as the formation of stable emulsion
Kieffer, Raphaëlle. « Développement de nouveaux catalyseurs pour la dépolymérisation de la lignine par voie d’oxydation ». Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10124/document.
Texte intégralLignin is one of the most abundant biopolymers on earth. It is issued from plants and represents the largest source of aromatics in biomass. Projects aiming at depolymerizing lignin to obtain value-added small molecules for the chemical industry are more and more developed due to the high potential of this bio-resource. The goal of our project was to develop a new catalytic system for the depolymerization of lignin. We have been interested in designing new homogeneous and heterogeneous catalysts based on the known structure of the Fe(TAML) complex. We have studied their reactivity and stability under oxidative catalysis conditions, and have compared them to the characteristics of the existing Fe(TAML). To do so, the catalysis study has been realized on lignin small model molecules to avoid the analytical problems related to a polymer backbone. In a first hand, we will present the strategy of functionalization of the known TAML ligand to design new complexes to be grafted on a silica support. In a second hand, we will talk about the results of oxidative catalysis in homogeneous and heterogeneous conditions, and the influence of the ligand structure change on the activity of the catalysts
Wang, Xia. « Artificial Photosynthesis : Carbon dioxide photoreduction and catalyst heterogenization within solid materials ». Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET025/document.
Texte intégralIn the context of global warming and the necessary substitution of renewable energies (solar and wind energy) for fossil fuels, efficient energy-storage technologies need to be urgently developed. Recently, energy storage via the reduction of CO2 has seen renewed interest. Although reduction of CO2 into energy-dense liquid or gaseous fuels is a fascinating fundamental issue, its practical implementation in technological devices is highly challenging due to the high stability of CO2 and thus the endergonic nature of its transformation. Furthermore, the reactions involve multiple electrons and protons and thus require efficient catalysts to mediate these transformations.The objective of this thesis is to investigate different strategies for the storage of solar energy in chemical compounds, through visible-light-driven CO2 reduction. This thesis comprises of two main parts. After an introduction, the first part describes the investigation of homogeneous catalysts in combination with a photosensitizer, either separately or connected covalently. Due to the easily-tunable synthesis and facile characterization of molecular catalysts, homogeneous photosystems are more controllable and can give deep insight into product selectivity and mechanistic issues.With regards to future applicability, however, homogeneous catalysis often suffers from additional costs associated with solvents, product isolation and catalyst recovery, amongst other factors. The integration of molecular catalysts into solid platforms offers the possibility to maintain the advantageous properties of homogeneous catalysts while moving towards practical system designs afforded by heterogeneous catalysis. The second part of this thesis is therefore the immobilization of molecular catalysts within solid materials, namely MOFs and PMO. The ultimate goal of this thesis is to incorporate both catalyst and photosensitizer into the solid support
Bjoerkert, U. Stefan. « High temperature COâ†2 permselective planar membranes ». Thesis, University of Warwick, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340092.
Texte intégralKim, Kyungduk. « Novel Nanocatalyst for the Selective Hydrogenation of Bio-Oil Model Compounds ». Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16353.
Texte intégralFullana, Olga. « La gramàtica inèdita de Pau Cardellach i Busquets ». Doctoral thesis, Universitat de Girona, 2014. http://hdl.handle.net/10803/398239.
Texte intégralThis thesis focuses on the edition and study of the Catalan Grammar of Pau Cardellach i Busquets (1818-1879), an unpublished work of which there is only one copy, handwritten, today at the University of Girona. Cardellach's grammar, which only known by indirect references, is an original work that exemplifies a different outlook on the Catalan language than those we knew so far in the nineteenth century. Its study helps to better define the late process of grammatical encoding of Catalan, and enriches the history of philology of Catalan. The necessary work to contextualize this book has also demanded a thorough study of its author and the circumstances that led to his grammar. Therefore, the thesis is divided internally into three sections: a) the bio-bibliographic study of Pau Cardellach and the circumstances in which he produced his Catalan Grammar; b) the critical edition of the work, with attention to all material respects, to the textual problems and to interventions to make it available to scholars; and c) the detailed contents and peculiarities of grammar, and their relevance to contemporary grammatical context study
Ivaldi, Chiara. « Hybrid catalysts based on N-heterocyclic carbene anchored on hierarchical zeolites ». Doctoral thesis, Università del Piemonte Orientale, 2021. http://hdl.handle.net/11579/127848.
Texte intégralMichalska, Malina. « Development of new gold-catalyzed strategies in N-acyliminium ion chemistry ». Thesis, Le Havre, 2013. http://www.theses.fr/2013LEHA0027/document.
Texte intégralThe research project is centred on the development of new gold catalyzed transformations in N-acyliminium ion chemistry. The objective of our first part of the project is to develop an enantioselective gold-catalyzed 5 exo-dig intramolecular hydroalkoxylation/aza-Ferrier-Petasis rearrangement sequence. This sequence could give an asymmetric and atom economic expeditious access to the structure of hydropyrrolizidines, which are known to be potential biologically active compounds. A second part of the project is devoted to the development of the first catalytic alkynylation of cyclic N-acyliminium ions using N,O-acetals. This type of reaction is potentially an important transformation, giving rise to propargylic amine derivatives amenable to further interesting synthetic manipulations en route to nitrogen-containing natural products and some analogs. Considering our objectives, key features is the use of TMS alkynes in conjunction with gold complexes that have been paired with poorly nucleophilic counter-ions. To broaden the scope of catalysis based on gold, it is important to extend the range of substrates and functional groups that can be activated by gold complexes. A final section is devoted to the sequential catalysis which designs the promotion of catalytic multistep processes. In this way, two fundamentally distinct chemical transformations are catalytically promoted in a single flask. This research area allows the rapid and efficient reach of complex molecular frameworks with improved yields and resource efficiency. Therefore, this is an exciting theme in modern organic synthesis that has recently stimulated the report of numerous excellent contributions
Stoica, Otilia Violeta. « Synthesis of Large Hydroacenes and Related Compounds Using Gold(I) Catalysis ». Doctoral thesis, Universitat Rovira i Virgili, 2021. http://hdl.handle.net/10803/671555.
Texte intégralEsta tesis doctoral presenta el desarrollo de nuevas estrategias para la síntesis de hidrocarburos aromáticos policíclicos, incluyendo acenos y sus análogos. En primer lugar, una nueva síntesis iterativa ha sido llevada a cabo para preparar acenos largos no sustituidos, en base a la cicloadición formal [4+2] de 1,7-eninos catalizada por Au(I) estudiada previamente por nuestro grupo. Esto permitió la obtención de nuevos hidroacenos, desde tridecaceno-H8 hasta heptadecaceno-H10. La deshidrogenación en una superficie de Au(111) del primer precursor produjo el compuesto tridecaceno, el aceno más largo conocido hasta ahora. Los precursores de otros derivados de acenos perteneciendo a otras categorías, como indacenos, acenos que contienen ciclobutadienos o heteroacenos han sido obtenidos usando nuestra cicloadición formal [4+2] de nuevos 1,7-eninos. La generación y caracterización de los acenos en superficies metálicas ha sido investigada utilizando técnicas de microscopia electrónica. Dos análogos de la primera clase, s-indaceno[1,2-b:5,6-b’]ditetraceno y as-indaceno[2,3-b:6,7-b’]ditetraceno, han sido obtenidos por cicloadición de un precursor bis-dihidrotetraceno en una superficie de Au(111). Se ha observado que el último derivado de indaceno participa en cicloadiciones intermoleculares sin precedentes en superficies, produciendo moléculas en forma de T. La reacción también tiene lugar cuando pentaceno y octaceno se usan como dienófilos. Finalmente, la orto-alquinilación C–H de aldehídos aromáticos catalizada por Rh(III) ha sido investigada para obtener nuevos sustratos para la síntesis de poliarenos. La reacción está promovida por un grupo director transitorio y permitió construir una variedad de compuestos mono- y doblemente alquinilados. Los inales obtenidos han sido usados en la preparación de dibenzopentalenos sustituidos, isoquinolinas, indoles e indolinas.
This Doctoral Thesis covers the design of novel strategies for the synthesis of polycyclic aromatic hydrocarbons, such as acenes and their analogues. For instance, a new iterative synthesis was elaborated for the preparation of higher unsubstituted hydroacenes, based on our previously developed gold(I)-catalyzed formal [4+2] cycloaddition of aryl-tethered 1,7-tetraenynes, and enabled the formation of unprecedented hydroacenes, from tridecacene-H8 to heptadecacene-H10. The Au(111) surface-assisted dehydrogenation of the former precursor afforded the parent tridecacene, the longest acene known until now. The precursors of acene derivatives belonging to diverse categories, such as indacenes, cyclobutadiene-containing acenes or heteroacenes have been acquired by applying our gold(I)-catalyzed formal [4+2] cycloaddition to newly developed 1,7-enynes. The surface-assisted formation of the parent acenes has already been investigated or is currently ongoing. Two analogues from the first category, s-indaceno[1,2-b:5,6-b’]ditetracene and as-indaceno[2,3-b:6,7-b’]ditetracene, were obtained through cycloaddition of a bis-dihydrotetracene precursor on a Au(111) surface. The latter indacene derivative was found to undergo an outstanding intermolecular cycloaddition, rendering T-shaped molecules. The reaction was also successful when pentacene and octacene were employed as dienophiles. Finally, the Rh(III)-catalyzed ortho C–H alkynylation of aromatic aldehydes was investigated in order to obtain new versatile building blocks for the synthesis of polyarenes. Enabled by the formation of an imine as transient directing group, this transformation provided a wide variety range of mono- and di-alkynylated products. The acquired ynals were then successfully engaged in the preparation of substituted dibenzopentalenes, isoquinolines, indoles and indolines.
Gobé, Valérian. « Cyclisations métallo-catalysées pour la synthèse de composés indoliques polycycliques ». Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS057/document.
Texte intégralThe indole ring is one of the most prominent heterocycle in natural products or bioactive compounds. The access to complex structures featuring several cycles, stereogenic centers, is one of the main challenge en route to the discovery of new potentially bioactive structures. During this PhD work, we developed metallo-catalyzed cyclizations of tetrahydro-β-carbolines presenting an unsaturated function to access to complex chiral, polycyclic compounds. The asymmetric organocatalyzed Pictet-Spengler reaction was used as a key step for the control of the asymmetry, starting from N-allyl tryptamines and allenaldehydes. The corresponding tetrahydro-β-carbolines were obtained in excellent yields and enantiomeric excesses.Several cyclization reactions were developed using these substrates, catalyzed by Pd(0) or Au(I) complexes, furnishing the targeted chiral tetracyclic derivatives. The mechanisms of these reactions, the regio-, chem- and diastereoselectivity of these reactions was studied. The large numbers of compounds that have been obtained via these routes present a large structural diversity that will hopefully lead to important findings in the field of bioactivity determination
Zheng, Run. « Towards heterogeneous catalysis and catalyst design :a density functional theory study on Fischer-Tropsch synthesis ». Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492328.
Texte intégralAlsayary, Omar. « Group 4 and Group 10 post metallocene ethylene polymerization catalysis : catalyst structure-polymer properties relationship ». Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/group-4-and-group-10-post-metallocene-ethylene-polymerization-catalysis-catalyst-structurepolymer-properties-relationship(ae5d83a2-4e13-4b8c-b7cc-cf7d67667d3d).html.
Texte intégralJia, Zixian. « Elaboration des matériaux composites nanostructurés Ag, Au/TiO² pour la dépollution des effluents gazeux avec une activation par plasma ». Thesis, Paris 13, 2013. http://www.theses.fr/2013PA132050.
Texte intégralDuring this Phd work, we have developed a plasma-catalytic process of acetaldehyde removal using a diphasic process coupling a nano-structured catalyst and an atmospheric pressure plasma. The elaboration of the nanoparticulate catalyst has been firstly studied. Then its performance coupling with plasma has been investigated. The monodispersed titanium-oxo-alkoxy nanoparticles are generated in the sol-gel reactor with turbulent micromixing and deposited onto glass plates or glass balls as monolayer nanocoatings. The silver and gold deposition is achieved by the ions reduction at UV-A light illumination. The photocatalytic growth kinetics and nanoparticle morphology are studied experimentally by the TEM, SEM and AFM methods. It’s also interesting to discuss the mechanism of the nanoparticles formation and evaluate its quantum efficiency. The drawn conclusions are supported theoretically through the calculation of the absorption spectra. Then the efficiency of the process coupling a dielectric barrier discharge and a fluidized nanostructured silver and gold based bed for the degradation of a model pollutant (acetaldehyde CH₃ CHO) is studied. In the first part, the efficiency of the plasma alone process is discussed, in terms of pollutant removal and CO and CO₂ production. In the second part, CH₃ CHO removal as well as COx production is studied as a function of the photocatalytic reduction time of Ag⁺ and Au³⁺ ions, which is related to the deposited silver and gold mass. The pollutant removal pathways, including homogeneous chemistry in the plasma phase and heterogeneous chemistry on the surface, are discussed. Finally, the production of main by-products is presented and compared between Ag and Au catalysts
Poupart, Romain. « Nanoparticules métalliques@polymères poreux : matériaux hybrides innovants pour la catalyse supportée ». Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1174/document.
Texte intégralPorous materials based on polymers have been the subject of intense and various researches since their discovery until now. Their unique and remarkable properties, like their easy functionalization or their large porosity range reachable for instance, coupled with their low production cost makes them attractive for numerous applications. Among them, supported catalysis is booming, especially since the rising of nanoparticles. During this Ph.D. contribution, we have developed different polymeric materials, which could be used as support, focusing mainly onto three types: bulky materials, porous polymeric matrixes into capillaries and porous polystyrene arising from the selective degradation of diblocks copolymers.Firstly, different strategies have been employed for the immobilization and the generation of nanoparticles onto bulk materials. On the one hand, the synthesis of a monomer, bearing a disulphide bridge which can, after a reduction step, free a thiol moiety allowing us to anchor gold nanoparticles. On the other hand, a new route to reduce nanoparticle has been employed using gaseous hydrogen. In another part, the syntheses of different polymeric matrixes into capillaries have been made. First, we used an already known matrix, based on N-acryloxysuccinimide -after modification step via thiol-ene reaction and nucleophilic substitution by amines- to anchor copper or gold nanoparticles, respectively. Also, a new matrix based on cyclic carbonates has been used, after modification, to immobilized platinum nanoparticles. Finally, starting from diblocks copolymers possessing different junctions between both blocks (disulphide bridge or acetal), porous polystyrenes have been obtained. The copolymers bearing an acetal have been implemented to immobilized gold nanoparticles, catalysing several reactions like nitro reduction, boronic homocoupling as well as the cascade reaction of both
Joutet, Karim. « Catalanité et « immigration » espagnole dans le discours politique et intellectuel catalan du XXe siècle : genèse et évolution ». Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/665853.
Texte intégralLe travail repose sur un constat selon lequel le terme « immigré » est présent dans le discours politique et intellectuel catalan depuis le début du XXe siècle afin de désigner les Espagnols venus vivre en Catalogne. L’appellation choisie par le discours pour désigner les migrants venus d’autres régions d’Espagne est en contradiction avec sa définition qui sous-entend un dépassement de frontière étatique. La distinction du lieu d’origine permet d’en désigner une autre : celle de l’identité. Une différence est créée et entretenue entre deux groupes vivant sur un même territoire et partageant une même nationalité espagnole, mais dont le lieu de naissance est à l’intérieur ou à l’extérieur de la Catalogne. En développant une image de l’« immigré » et en la maintenant jusqu’au XXIe siècle, le discours catalan insiste sur le fait que ce flux de population provienne d’un extérieur. S’exprimer sur ce sujet permet d’affirmer sa propre vision de la société catalane, comprise comme multiculturelle, biculturelle ou comme une unique communauté. Le point commun entre ces différentes manières de concevoir la catalanité réside dans l’affirmation de la cohérence et l’autonomie du groupe récepteur capable d’accueillir les autres, malgré les craintes de certains. Réfléchir sur le phénomène migratoire permet finalement au discours d’affirmer sa propre identité et l’existence d’une nation catalane. L’image du nouvel arrivant est bien au centre de luttes de classements et apparaît comme un instrument permettant d’imposer une idéologie nationale ou une manière de concevoir la société catalane dans le discours politique ou universitaire. On assiste toutefois à un glissement du premier vers le deuxième, synonyme du passage à la mémoire historique d’une représentation qui a fait polémique tout au long du XXe siècle. Enfin, les recherches réalisées montrent bien l’implication de ladite « immigration » espagnole dans la réflexion autour de la construction identitaire catalane. Tout d’abord, de par sa présence et le débat qu’elle provoque, elle contraint le système interdiscursif à mettre en place une série de rapports de force dans le but de définir sa propre identité. Elle y participe physiquement en étant visible en tant qu’« immigration » lors d’événements clés dans la construction identitaire, comme ce fut le cas pendant la Diada de 1977. Elle s’est également rendue visible et active en participant à la vie politique catalane : Francisco Candel en est un exemple parmi d’autres. La participation du phénomène à la réflexion mise en place par le discours politique et intellectuel catalan apparaît aussi à travers l’apport des générations nées en Catalogne. Au fur et à mesure de nos analyses, nous nous sommes aperçu qu’elles n’étaient plus considérées comme « immigrées » ni comme étant un problème mais comme un apport pour la Catalogne. La seconde génération est d’ailleurs active dans le travail de reconnaissance de l’« immigration », notamment par les travaux des scientifiques à partir des années quatre-vingts. L’observation des noms des universitaires ayant participé à institutionnaliser la représentation de l’« immigré » nous permet d’avancer cette affirmation, qui devra être confirmée ou infirmée par des études complémentaires.
This work builds up on the fact that the word « immigrant » is present on the political and intellectual Catalan discourse since the beginning of the XXth century to reference Spaniards coming to live in Catalonia. The appellation chosen by this discourse to name immigrants coming from other regions of Spain is openly contradictory with its definition that implies crossing a national frontier. The distinction regarding place of origin allows for anotherone: Identity. This difference is created and sustained by these two groups living under the same territory and sharing the Spanish nationality, but whose place of birth is inside or outside Catalonia. Developing an image of the « immigrant » that subsisted until the XXI st century, the catalan discourse insists on the fact that this flow of people come from an outside. Expressing oneself over this subject allows for an original vision of the Catalan society, understood as multicultural, bicultural or as a unique community. The common point between this different ways of conceiving catalanity resides on the affirmation of the receptor group ´s coherence and autonomy and its capacity to host others, in spite of the fear that may arise. Thinking about the immigration phenomenon enables the discourse to affirm its own identity and the existence of a catalan nation. The image of the newcomer is immerse in between the classification struggles and appears as an instrument that allows for an imposition of a national ideology or a way of conceiving the catalan society in the political or academic discourse. We are witnessing a slippage from the first one towards the second, synonym of a transition to historical memory of a presentation that was controversial all along the XXth century. Finally, research has shown the implications of the mentioned Spanish « immigration » in the debate surrounding the catalan identity construction. First off, by its presence and the debate it creates, forcing the interdiscursive system to place a series of power relationships aiming at defining its own identity. Also participating physically, as being visible as « immigration », taking a key role in the process of building identity, as it was the case during the Diadaof 1977. It was visible as well in the catalan political sphere : Francisco Candel is an example among others. The phenomenon ´s participation during the debate created by the political and intellectual discourse is made visible also through contribution of the generations born in Catalonia. As we went along the analysis, we realized they were no longer considered as « immigrants » nor as a problem but as a contribution to Catalonia. The second generation is active in its reconnaissance work of « immigration », especially through the scientific studies starting on the eighties. The observation of the names of the universities who participated in institutionalizing the representation of the « immigrant » allows us to further pursue this affirmation, that has to be confirmed or infirmed by complementary studies.
Angelo, Laetitia. « Développement de catalyseurs pour la synthèse de méthanol produit par hydrogénation du dioxyde de carbone ». Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAF051/document.
Texte intégralNumerous measures to reduce anthropogenic emissions of greenhouse gases, especially CO2, already exist; however they are still insufficient. It is in this context that the ANR project VItESSE2 emerged to develop a method for converting CO2 produced by industries. The aim of this project is to transform CO2 into methanol, by reduction with hydrogen produced by water electrolysis using electricity provided by decarbonised energies (nuclear and renewable energies). This process also allows to secure a management function of the electrical grid by connecting the production of hydrogen to the available quantity of electricity in the network. The main objectives of this thesis are the synthesis and the characterization of efficient catalysts for CO2 hydrogenation into methanol and the development of reaction conditions leading to improved methanol productivity. The optimization of catalyst systems allowed to develop a CuO-ZnO-ZrO2 catalyst competitive in relation to commercial catalysts currently on the market
Bourouina, Amine. « Desperately Seeking For The Catalytic Species In Suzuki-Miyaura Reaction ». Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1258.
Texte intégralThe use of ligand-free supported Pd is an attractive idea because it avoids problems related to the presence of the ligands (cost and toxicity). Also the catalyst is easily recovered at the end of the reaction by conventional methods such as filtration or decantation. Thus, it is easier to meet regulations in Active Pharmaceutical Ingredients (<10 ppm). However, the presence of molecular or atomic Pd species in solution when using solid catalysts has created an important discussion on the true nature of catalysis. This last could be heterogeneous on the surface of the supported Pd or homogeneous via species in solution. In this work the Suzuki-Miyaura (SM) reaction was chosen as the target reaction. In the absence of an overall kinetic study in the literature, a kinetic study was carried out with a molecular catalyst. It provided a mechanistic law that represents the homogeneous part of the reaction. Furthermore, an innovative test (“split flow reactor”) has been proposed. It permits to distinguish between the homogeneous and heterogeneous contributions and to determine the nature of the species that catalyze the reaction. It was used in the reaction of different iodo, bromo, and chloro aryls. Several supported catalysts were used by varying the nature of the support and the oxidation state of Pd (Pd (0) and Pd (II)) in the initial precursor. Finally, a reactor model has shown that for the same iodoaryl, whatever the nature of the solid, the supported Pd seems to release the same active species in solution. These species catalyze the SM reaction with initial activities of the order of 500 000 h-1. The split flow reactor is a new, easy-to-use test. Accompanied with online analysis techniques, it can be used to track the evolution of catalytic species in real time and to study other chemical systems
Jones, Rebecca S. « Carbon Dioxide as a Benign Solvent for Homogeneous Catalyst Recovery and Recycle ». Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/11641.
Texte intégralCoffin, Aaron. « Efforts at Expanding the Scope of Peptides as Enantioselective Organic Catalysts ». Thesis, Boston College, 2008. http://hdl.handle.net/2345/968.
Texte intégralThesis (MS) — Boston College, 2008
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
Clarebout, Gervais. « Catalase endogène et catalase internalisée chez Plasmodium ». Lille 1, 1995. http://www.theses.fr/1995LIL10193.
Texte intégralLummiss, Justin Alexander MacDonald. « Olefin Metathesis : Life, Death, and Sustainability ». Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32277.
Texte intégralDi, Jiexun. « Development of highly active internal steam methane reforming catalysts for intermediate temperature solid oxide fuel cells ». Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:a36ce531-e7b2-48fb-a59b-dbca6b435643.
Texte intégralKAMYAB, ALI. « Preparation and evaluation of sulfided NiMo/γ-Al2O3 hydrotreating catalysts ». Thesis, KTH, Skolan för kemivetenskap (CHE), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190904.
Texte intégralPereira, João Clécio Alves. « Desenvolvimento de complexo de Ru(II) com 3-metilpiperidina para atuar como catalisador em reações de polimerização via metátese de olefinas cíclicas ». Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-16032018-102844/.
Texte intégralThe 3-methylpiperidine (3-Mepip) molecule was investigated as ancillary ligand in a novel [RuCl2(PPh3)2(amine)] type complex for ring-opening metathesis polymerization (ROMP) of norbornene (NBE) and norbornadiene (NBD). The synthesis of the new complex was performed from the precursor complex [RuCl2(PPh3)3], and it was characterized by: EPR, CHN elemental analysis, infrared (FTIR) and 31P NMR (1H). From the obtained results it was possible to propose a pentacoordenado complex with square-shaped pyramid geometry (PBQ), with chloride ions trans-positioned in the equatorial plane of the coordinating metal sphere, with the amine occupying the apical position of the pyramid due to its strong σ-donor character. The ROMP reactions of NBE and NBD monomers using the new complex were performed under argon atmosphere as a function of the [monomer]/[Ru] molar ratio (1000, 3000, 5000, 7000 and 10000), reaction time (5, 30 and 60 min) and temperature (25 and 50 ° C). With a volume of 5 µL of ethyldiazoacetate (EDA), at 25 °C and a 5000 molar ratio of monomer for 5 min, 65% polyNBE was obtained with Mn = 0.8 x 105 and IPD equal to 1.9. The polymers obtained with NBD showed 20% yield at 25 °C for 5 min. The polymers obtained with norbornadiene showed a yield of about 20% at 25 °C for 5 min. Polymerization reactions in air atmosphere resulted in values close to those observed in argon atmosphere, suggesting that the complex presents resistance to oxidative processes caused by O2 from the ambient atmosphere. The polymerization reactions were performed in the presence of other diazocompounds benzyldiazoacetate (BDA) and tert-butyldiazolacetate (TBDA) as sources of carbenes. In order to evaluate the electronic and steric influence caused by the different R groups of these diazocompounds, it was observed that ethyldiazoacetate EDA) presented the best yield values of the isolated polymers, probably due to the balance in the steric and electronic characteristics of this diazo in front of the Ru(II) center.
Attoui, Mariam. « Nanocatalyseurs hélicoïdaux chiraux à base de polyoxométallates pour les réactions d’oxydation énantiosélectives ». Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0447/document.
Texte intégralChiral polyoxometalates (POMs)-based materials have attracted particular attention in recent years due to their remarkable properties and potential application, especially in the field of catalysis. The goal of this thesis is to design a series of enantiopure nanohelical structures based on polyoxometalates (NANOPOM), for their use as heterogeneous oxidation catalysts. Two approaches were used to prepare these new materials. The first one based on the immobilization of POMs on silica nanohelices and nanoribbons by electrostatic and direct adsorption grafting. These inorganic structures increase the stability and make them less sensitive to external environment. The second approach is to include POM units within the structure of organic nanoribbons and nanohelices during self-assembly of 16-2-16 (L)- or (D)-tartrate gemini amphiphile and POM in water. The characterization of these NANOPOM hybrids by using various techniques such as 31P NMR, UV-Vis, DRIFT, Raman, TEM, HR-TEM and EDX was performed and confirms the structure of these materials, especially the grafting of POM to helical supports. These materials are generally stable, and the induction chirality to the POM anion was confirmed by circular dichroism, highlighting the enantiopurity of these NANOPOM materials. The catalytic properties of these POM hybrids have been tested in the oxidation of sulfides. They are active and recoverable catalysts, unfortunately with no significant enantioselectivity observed in the condition used. We expect that new NANOPOM systems in which POM units are introduced within the structure of nanostructure during gel formation, followed by silica transcription will be more stable, an important feature for their use as recoverable catalyst
Sachse, Alexander. « Synthèses de microréacteurs à base de monolithes siliciques et zéolithiques à porosité hiérarchique pour le développement de la catalyse en flux ». Thesis, Montpellier, Ecole nationale supérieure de chimie, 2011. http://www.theses.fr/2011ENCM0006/document.
Texte intégralThe aim of this work is the synthesis and the functionalization of silica monoliths with hierarchical porosity and their use as catalytic microreactors for flow-through chemistry. A reproducible synthesis of the silica monoliths was elaborated. The functionalization with a variety of functions has been performed, such as aminopropyl groups, aluminium oxide, MOFs (CuBTC), and palladium nanoparticles. These functionalized silica monoliths have been used for the Knoevenagel condensation, Diels-Alder reaction and Fiedländer reaction, where they show increasing productivities compared to classically used reactors (batch, packed-bed) and enable process automation. The pseudomorphic transformation of silica monoliths in zeolite monoliths in the SOD and LTA phase has been elaborated. We have preformed the first implementation of a macroporous zeolite monolith as microreactor for the fine chemical production in flow continuous conditions. The zeolite monoliths have been tested for dynamic ion exchange and are promising materials for the use as decontaminants of radioactive discharges
Baker, Ruletha Deon Goodwin Douglas C. « Roles of an 'inactive' domain in catalase-peroxidase catalysis modulation of active site architecture and function by gene duplication / ». Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Fall/Dissertations/HARTFIELD-BAKER_RULETNA_19.pdf.
Texte intégralBoscaro, Paolo. « One-pot synthesis of structurated of TiO2 materials easy to handle (not nanoparticles) for photocatalysis under visible light and sunlight ». Thesis, Montpellier, Ecole nationale supérieure de chimie, 2016. http://www.theses.fr/2016ENCM0009.
Texte intégralThe aim of this study is to develop titania based materials able to perform photocatalytic reaction in flow condition, under sunlight or visible light, with special physical and chemical properties in order to overcome common photocatalysts’ deficiencies like: mechanical stability, pressure drop, low mass transfer and contact time, reduced wavelength range absorption, photo-generated charge lifetime, and in general all features that limit photocatalysts efficiencies. Three synthesis methods have been developed and optimized to obtain TiO2 monoliths with shape and dimension that can be adapted to any specific application. TiO2 monoliths, displaying bimodal macro-mesoporous interconnected network together with an elevated mechanical and chemical stability, have been used as flow photocatalyst microreactor under different flow rate conditions. Synthesized monoliths displayed enhanced visible light absorption, enabling them to efficiently operate in a vast range of illumination. TiO2 monoliths absorption on the visible range of the spectrum is attributed to carbon-nitrogen containing species within the material. Orange G degradation in aqueous medium have been performed both in batch and flow reactors under sunlight, visible light and UV light. All reactions resulted in complete mineralization of pollutant, with higher degradation rate than TiO2 nanoparticles benchmark material (P-25) when visible light is used. No photocatalyst deactivation have been detected after 85 hours of wastewater treatment in flow conditions. Similar TiO2 material, with a free-standing thick-film shape, have been used to perform photocatalytic water splitting under visible light. Another strategy has been developed to synthesize a TiO2/CuO self-standing film to enhance charge separation giving unexpected results in terms of hydrogen production
Zhao, Guangkuan. « Reduction of thioketals by TMSCl/NaI association and synthesis of heterocycles from ortho-substituted arylalkynes ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS392.
Texte intégralThis thesis is divided into two distinct parts. The first show that, after a comprehensive study of thioketals desulfurization reactions listed in the literature, the use of TMSCl / NaI combination is a modern method of choice to reduce thioketals since it does not require any toxic metal. In a second part, we have been interested in the synthesis of heterocycles (isocoumarins, benzothiophenes and indoles) by the study of original heterocyclization reactions. The thesis is presented with the presentation and discussion of publications (7)
Savourey, Solene. « Nouveaux procédés de réduction catalytique du CO2 en consommables chimiques ». Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV051/document.
Texte intégralFossil resources have been extensively used for the past 200 years allowing a fast paced industrializationin our society. However we are facing today several challenges to preserve our way of life 1) CO2 shouldbe captured and stored/used to avoid large quantity of CO2 to be released in the atmosphere 2) Bypassthe use of fossil resource by using another source of carbon for the synthesis of chemicals 3) Developefficient energy storage technologies to rely more on renewable intermittent energy sources. As CO2 is acheap widely available resource, this waste could be used as well as a source of carbon for the synthesisof value added chemicals but also as a way to store energy in the tandem CO2/MeOH. However as it isan inert gas few processes using CO2 have been industrialized so far.Inspired by Nature’s way to use CO2 we decided to design new reactions from carbon monoxide andformic acid, two derivatives easily available from CO2 that could enable us to overcome the limitationwe faced with CO2. We therefore studied the transformation of CO2 to methanol using formic acid as anintermediate and a reductant and we subsequently used this reaction to perform the methylation ofaromatic amines using formic acid. Finally we developed a new reaction of amines homologation withcarbon monoxide allowing the formation of several C–C bonds
Rus, Yahdi Bin. « Nanocomposites à base de graphène fonctionnalisé pour le stockage de l'énergie et la catalyse ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLN068.
Texte intégralAbstract: Functionalized graphene sheets with a ratio C/O~x (FGSx) was further functionalized with a tetrazine derivatives (3,6-bis(2-pyridyl)-1,2,4,5-tetrazine) by inverse demand Diels-Alder cycloaddition reactions. Functionalized FGS20 and FGS13 potential applications were explored on energy storage (super-capacitor) and catalysis (oxygen reduction reaction).In supercapacitor applications, nanocomposites made of functionalized FGS20 with polypyrrole were synthesized in two steps by first incorporating pyridine-pyridazine functions on FGS20 surface through cycloaddition followed by electropolymerization of pyrrole in acetonitrile. The specific capacitance of the material was measured by galvanic charge-discharge cycles and the stability upon cycling investigated in various electrolytic media (acetonitrile, ionic liquid, acidic, and neutral water) in comparison with non-functionalized FGS20 with or without polypyrrole. While acetonitrile reveals pure capacitive behaviour for all investigated mate-rials, acidic water is the medium where the capacitance values are the highest and surprisingly where nano-composites with polypyrrole show better capacitance retention upon cycling than graphene alone. A positive impact of graphene functionalization prior to electropolymerization was demonstrated in all electrolytic media (capacitance losses limited to less than 8% after 1500 cycles in all media but neutral water), highlighting the interest of interface control in this kind of nanocomposites
Narbonne, Vanessa. « Catalyse par les métaux de transition : catalyse duale palladium-norbornène pour la synthèse diastéréosélective de dibenzoazépines et construction de biaryles via catalyse photorédox médiée par un complexe de ruthénium ». Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS115/document.
Texte intégralCatalysis by transition metal has considerably grown these decades and has become a powerful tool in organometallic chemistry. The CH ortho fonctionnalisation reaction, involving a duale palladium/norbornene catalysis, discovered at the end of the 90’s, allowed a breakthrough in the field of multi-component reactions. It provides access to polycyclic structures through an original mechanism, involving a palladacycle formation. It is the first catalytic reaction including three oxidation states of palladium (0, II and IV). In a context where the chemistry is going to be more ecocompatible, we wished taking advantage of this reaction to synthetize dibenzoazepines. They represent interesting scaffold both as organocatalysts and as bioactive compounds, however the existing synthesis don’t allow diversifying the structure of these molecules and often requiring multi-step sequences or toxic reagents. Dibenzoazepines synthesis has been realised according a three components approach from readily available reagents, a bromobenzylamine, an ortho substituted aromatic iodide and an electrowithdrawing olefin via a CH ortho fonctionnlisation/Heck/aza-Michael sequence. Remarquably, this last step presents a total diastereoselectivity. Using racemic substituted bromobenzylamine shows the same selectivity thanks to a parallel kinetic resolution-like mechanism. The access to a wide range of molecules, and the corresponding imine via a retro-Mannich mechanism using an enolisable olefin demonstrates the robustness of the ortho CH fonctionnalisation reaction. Carbon-carbon bond formation by transition metal has been largely developped since decades. However, it often generate waste and use toxic reagent at high temperature. Photoredox catalysis is a great success recently and have the advantage to use light as energy source and small amounts of metal and organocatalyst. We have developed a method of biarylic coupling via a photoredox catalysis mediated by a ruthenium complex. Arene diazonium, the precursor coupled, have the advantage to generate diazote as waste, and realise an homolytic aromatic substitution on aromatic and heteroaromatic acceptors. Moreover, it takes place at room temperature without base. It is an alternative for the biarylic coupling and an green chemistry
Tang, Yue. « Catalyse asymétrique en présence de complexes d'or(I) - Un nouvel arsenal pour la construction d'architectures moléculaires ». Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEC038.
Texte intégralOver the last years, gold catalysis has gained considerable significance in organic synthesis, since it comprises atom-economic and highly efficient processes for the transformation of relatively simple substrates into valuable, highly complex molecular architectures. Despite these outstanding advances, the enantioselective variants have not flourished as fast and remain a highly challenging task. This project intends to address some technological barriers and contribute to fundamental research in the field of asymmetric cycloisomerization and domino reactions implying gold(I) and gold(III) catalytic systems, on a first approach, and highly modular chiral carbenic ligands. The ligands will be based on chiral N-Heterocyclic Carbenes (NHCs), as they represent a very effective and robust class of supporting ligands. More specifically, we will focus on the development of highly modular NHC architectures specifically designed to bring the chiral information in close proximity to the metallic center, which represents a key feature for an efficient asymmetric induction in gold catalysis. The target substrates of catalysis will be divided in two main classes, namely the 1,n-enynes and the unsaturated carbonyl/imino derivatives, since their gold(I)- and gold(III)-catalyzed conversion will afford a great molecular complexity. By taking advantage of the different reactivities and catalytic profiles of the NHC-Au(I) and NHC-Au(III) complexes, along with their silver counterparts, this project will allow the elaboration of a complete panel of efficient, general and unprecedented enantioselective catalytic systems towards the preparation of bio-relevant building blocks, precursors of natural products and biologically active molecules
Belarbi, Hichem. « Élaboration des zéolithes nano-structurées M-ZSM-5 (M=Cu, Cr et Fe) : Etude comparée des solides poreux minéraux et organométalliques MOFs dans l’oxydation de méthylènes benzyliques ». Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20192.
Texte intégralEnergy, sustainable development, and health are at the heart of contemporary concerns of the planet. The inevitable disappearance of fossil fuels, the severe consequences of carbon emissions on the environment and health require quick and effective solutions to supplement the first and minimize others. Among the solutions proposed, there are porous materials which have proven their effectiveness; however, there are still obstacles to be corrected or circumvented. In this thesis, we focus on the problem of bulky molecules' inaccessibility in micro pores of the materials we wish to study. In the first part, we optimize the material in this case, ZSM-5, with a reduction in particle size to a microscopic scale to another nano, which allows us to increase the external surface after changing certain parameters. In the second step, in order to give a catalytic entity to our support (zeolite), we activate with this material incorporating cations selected according to a specific property of the benzyl methylenes oxidation reaction. For this reason we developed different method of preparation. We conclude this thesis by catalysis with M-ZSM-5 (M = Cu, Cr and Fe) and a comparative study on the method of preparation and the MOFs that bears the same cations as mineral part which constitutes the materials
Boreux, Arnaud. « Development of new dual catalysis systems with gold and copper ». Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX053/document.
Texte intégralDuring the last decades, transition metal catalysis has become an essential tool in organic synthesis. Each year, thousands of publications report the development of new reactions mediated by metal complexes. This manuscript depicts our contribution to this field. The first chapter presents a general comparison of the reactivity of coinage metals (Cu, Ag, Au) complexes in catalysis, with a special focus on their ability to perform electrophilic activation (Au) or nucleophilic transfer (Cu) reactions. Representative examples are given to illustrate these concepts. In the second part of the manuscript, the synthesis of trifluoromethylated allenes and enones by gold(I) catalysis is reported. A general method for the preparation of CF3-allenes has been developed based on a gold(I)-mediated 1,5-hydride shift. The scope and limitations of the method, as well as some subsequent transformations of the products are described. Using similar substrates, a gold(I)-catalyzed [3,3]-acetate rearrangement was applied to the preparation of CF3-enones. The employment of this method into a one-pot procedure involving a subsequent Diels-Alder reaction is also reported. The third part focuses on the copper(I)-catalyzed borofunctionalization of allenes. The recent reports from the literature are reviewed, and our contributions to this area of research are described through the study of a new copper(I)-catalyzed allene boroacylation method. Finally, preliminary results on the elaboration of a copper(I)/gold(I) catalytic one-pot process are presented
Barthelemy, Anne-Laure. « Synthèse de sulfoximines perfluorées hautement fonctionnalisées et de sulfilimino iminiums. : Etude de leur application dans des réactions de perfluoroalkylation par catalyse photoredox ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLV080/document.
Texte intégralFluorine atom is essential in our everyday life. It is necessary for the development of battery, refrigeration (Fréon), liquid crystals which constitute the screens of phones, or materials (Téflon®). But its main role is in life sciences. The introduction of a fluorine atom modifies the physical and chemical properties of organic molecules, allowing to modulate and to enhance their biological activities. Its introduction in organic molecules constitutes a key challenge for chemists, which necessitates continually the development of new reagents for fluoration or perfluoroalkylation reactions. Among these, perfluorinated sulfoximines are electrophilic, nucleophilic or radical perfluoroalkylating reagents. Moreover, perfluorinated sulfoximines have peculiar properties with uses in material or life sciences.My PhD work falls within the project of our laboratory to develop a new general acces to perfluorinated sulfoximines and the synthesis of highly functionalized sulfoximines. My PhD work also deals with the synthesis of sulfilimino iminiums, derived from sulfoximines, which are efficient and versatile reagents for visible light-induced perfluoroalkylation reactions
Santamaria, Balaguer Francesc Xavier. « Prat de la Riba i la institucionalització d'un model de cultura catalana : l'obra cultural i pedagògica ». Doctoral thesis, Universitat Ramon Llull, 2010. http://hdl.handle.net/10803/9242.
Texte intégralL'obra i l'actuació de Prat s'han estudiat des d'una triple orientació: com a home d'idees, que sistematitzà els principis doctrinals del nacionalisme catalanista; com a home de partit, que defensà els objectius polítics del catalanisme; i com a home de govern, que aconseguí dur a la pràctica alguns dels objectius que s'havien formulat des del catalanisme polític.
A la nostra recerca ens hem plantejat l'objectiu d'estudiar si l'obra institucional de cultura que impulsà Prat de la Riba com a home de govern, des de la presidència de la Diputació de Barcelona i de la Mancomunitat de Catalunya, va respondre al pensament polític i social que formulà en l'obra que escrigué com a home d'idees i que defensà com a home de partit.
Utilitzant com a font de dades primàries, amb un criteri cronològic, el corpus format per l'obra escrita completa de Prat la Riba, es desenvolupen els objectius generals següents:
- Conèixer el pensament de Prat de la Riba fins a l'any 1905, en què fou elegit diputat provincial, en referència al marc social i polític, a l'anàlisi que en feia i a les propostes que presentava: és la concreció del plantejament polític i social que Prat formulà com a home d'idees i com a home de partit abans de ser escollit diputat i president de la Diputació provincial de Barcelona.
- Conèixer quins eren els objectius que es proposà assolir Prat des de l'actuació política i a través de l'obra institucional que, de 1907 a 1917, promogué des de la presidència, primer, de la Diputació provincial i, més tard, també de la Mancomunitat de Catalunya.
- Analitzar si existeix una correspondència directa entre les propostes que presentà, com a home d'idees i com a home de partit, i les realitzacions concretes que impulsà des de les institucions en l'àmbit de la cultura catalana, com a home de govern.
Complementàriament, prenent com a referent el marc polític i social del període, es desenvolupen els objectius específics següents:
- Presentar els objectius polítics que formulà el catalanisme polític a les sis primeres Assemblees de Delegats que celebrà la Unió Catalanista.
- Presentar les demandes de regeneració de la política espanyola que es feren des de Catalunya i la petició d'establir un concert econòmic.
- Presentar l'ús que Prat va fer del recurs de l'emissió de deute públic per a poder dur a terme l'obra institucional que impulsà des de la Diputació provincial de Barcelona i des de la Mancomunitat de Catalunya.
La tesi s'organitza en una part primera, en què es presenta l'obra de Prat de la Riba publicada en el període anterior a la seva entrada a la vida política activa, fins el març de 1905, obra que per la varietat de les temàtiques tractades i del públic a qui es dirigia tenia una component pedagògica de divulgació de l'ideari catalanista i dels objectius del catalanisme polític; una part segona, en què es presenta l'obra de Prat de la Riba publicada en el període comprés entre la incorporació a la vida política activa i la seva mort, des d'abril de 1905 fins a juliol de 1917, que es correspon amb el desenvolupament de l'obra de cultura; la recapitulació i conclusions de la tesi, la bibliografia i els annexos.
Enrique Prat de la Riba y Sarrá fue un destacado político catalán que, en el período comprendido entre 1907 y 1917, desde la presidencia, primero, de la Diputación provincial de Barcelona y, más tarde, también de la Mancomunidad de Cataluña, impulsó una destacada actuación en los ámbitos de las obras públicas, la beneficencia y la cultura.
La obra y la actuación de Prat se han estudiado desde una triple orientación: como hombre de idees, que sistematizó los principios doctrinales del nacionalismo catalanista; como hombre de partido, que defendió los objetivos políticos del catalanismo; y como hombre de gobierno, que consiguió llevar a la práctica algunos de los objetivos que se formularon desde el catalanismo político.
En nuestra investigación nos hemos planteado el objetivo de estudiar si la obra institucional de cultura que impulsó Prat de la Riba como hombre de gobierno, des de la presidencia de la Diputación de Barcelona y de la Mancomunidad de Cataluña, se corresponde con el pensamiento político y social que formuló en la obra que escribió y que defendió como hombre de idees y como hombre de partido.
Utilizando como fuente de datos primarios, con un criterio cronológico, el corpus formado por la obra escrita completa de Prat la Riba, es desarrollan los objetivos generales siguientes:
- Conocer el pensamiento de Prat de la Riba hasta el año 1905, en que fue elegido diputado provincial, en referencia al marco social y político, al análisis que hacía y a las propuestas que presentaba: es la concreción del planteamiento político y social que Prat formuló como hombre de ideas y como hombre de partido antes de ser elegido diputado y presidente de la Diputación provincial de Barcelona.
- Conocer cuáles eran los objetivos que se propuso alcanzar Prat desde la actuación política y a través de la obra institucional que, de 1907 a 1917, promovió desde la presidencia, primero, de la Diputación provincial y, más tarde, también de la Mancomunidad de Cataluña.
- Analizar si existe una correspondencia directa entre las propuestas que presentó, como hombre de ideas y como hombre de partido, y las realizaciones concretes que impulsó desde las instituciones en el ámbito de la cultura catalana, como hombre de gobierno.
Complementariamente, tomando como referencia el marco político y social del período, se desarrollan los objetivos específicos siguientes:
- Presentar los objetivos políticos que formuló el catalanismo político en las seis primeras Asambleas de Delegados que celebró la Unión Catalanista.
- Presentar las demandas de regeneración de la política española que se presentaron desde Cataluña y la petición de establecer un concierto económico.
- Presentar el uso que Prat hizo del recurso de la emisión de deuda pública para poder llevar a cabo la obra institucional que impulsó desde la Diputación provincial de Barcelona y desde la Mancomunidad de Cataluña.
La tesis se organiza en una parte primera, en que se presenta la obra de Prat de la Riba publicada en el período anterior a su entrada en la vida política activa, hasta marzo de 1905, obra que por la variedad de las temáticas tratadas y del público a quien se dirigía tenia una componente pedagógica de divulgación del ideario catalanista y de los objetivos del catalanismo político; una parte segunda, en que se presenta la obra de Prat de la Riba publicada en el período comprendido entre la incorporación a la vida política activa y su muerte, desde abril de 1905 hasta julio de 1917, que se corresponde con el desarrollo de la obra de cultura; la recapitulación y conclusiones de la tesis, la bibliografía y los anexos.
Enric Prat de la Riba i Sarrà was a very important catalan politician. Since 1907 to 1917 he was the president (firstly in the provintial Deputation of Barcelona and later in the Catalonia Union, too). He stimulated a emphasized actuation in the public works, the charity an the culture fields.
In the culture field Prat de la Riba worked on an extensive whole of actions that treated about the ortographic normalization of catalan language and the creation of institutions as, for example, the Catalan Studies Intitute, the Catalonia Library, the Popular Libraries, the Theatre Institute, the Industrial School and the Work School.
Prat's work and action have been studied from a triple point of view: as an ideas' man (systematizing the doctrinal points of catalan nationalism), as a party-s man (defending the politic catalanism objectives) and as a government's man (he attained to lead to practice some objectives that had been formulated from politic catalanism).
In our searching we have proposed the objective to study if the culture insitutional work that Prat de la Riba carried out as a government man (from the provintial Deputation of Barcelona and the Catalonia Union presidency) answered to the political and social thought that formulated in the work that wrote as an ideas man and he defended as a party man.
The corpus shaped by the complete writen work of Prat de la Riba has been used as a mainly source. The following objectives are developed:
- To know the Prat de la Riba thought until 1905, when he was elected provincial delegate, in reference to the social and political framework, to the analysis that he did and the proposals that he show: this is the summary of the political and social exposition that Prat designed as a ideas man and as a party man before been elected delegate and president of the provincial Deputation of Barcelona.
- To know the objectives that Prat de la Riba was thinking on since the politic action and trough the institutional work that, since 1907 to 1917, promoted from the presidence (firtsly, from provincial Deputation of Barcelona and later from Catalonia Union).
- To analyze if exists a direct correspondence between the proposal that he shows, as an ideas man and as a party man, and the concrete accomplishments that he carried out from the institutions in the catalan culture field, as a government man.
In addition, using as a reference the social and politic framework of the period, the following specific objectives are developed:
- To show the politic objectives that politic catalanism formulated to the six first ones Delegate Assemblies that celebrated the Catalanism Union.
- To show the regeneration requests of the Spanish politic that were done from Catalonia and the request to stablish an economic agreement.
- To show the use that Prat did from the emission's resort of the public debt to be able to carry out the institutional work that he did from the provincial Deputation of Barcelona and from the Catalonia Union.
The thesis is organized in two parts. The first one shows the work of Prat de la Riba published in the previous period to his active political life, until the March of 1905. The work pedagogic component of Catalanist ideology and the objectives of the Catalanist politic were caused by the extent topics treated and the public. The second one, shows the Prat de la Riba's work published in the period between the insertion in the active politic life and his death, from April of 1905 to June of 1917, that corresponds to the culture work development. Finally, the recapitulation and the thesis' conclusions, the bibliography and the annexe.
Biletskyi, Bohdan. « Développement de nouvelles transformations catalysées au cobalt ». Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0668/document.
Texte intégralThe application of cobalt in organic synthesis and catalysis has been known since the 1970s, especially in Pauson-Khand reaction. Until now, a lot of catalytic systems with cobalt have demonstrated their efficiency in various chemical transformations including [2+2+2] cycloadditions or the activation of C(sp2)-H bonds. In this manuscript are presented the chemical transformations based on the use of cobalt to catalyze atom-economical reactions, and the attempts to develop enantioselective versions. First of all, the activity of cobalt(I) catalysts was established for the cycloisomerisation reaction of dienynes giving bicycles[4.3.0]. The studies of different parameters of the catalytic system, as well as the scope reaction, will be presented. Moreover, the catalysts based on cobalt(II) acetate proved to be very efficient for hydroalkynylation reactions. The hydroalkynylation reaction of vinylaziridines was developed after catalyst optimisation and, the scope reaction according to the nature of reactants was defined. Finally, preliminary studies of enantioselective allylation using cobalt(II) catalysts were performed. These promoters were found to be activators of the carbonyl group, thus compromising the asymmetric version of the reaction
Wu, Zhiyong. « Synthèse de nouveaux catalyseurs chiraux d’or(I) et applications en catalyse énantiosélective ». Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS244.
Texte intégralThe gold(I)-catalyzed cycloisomerization reactions provide powerful tools for the synthesis of heterocycles and carbocycles in both racemic and enantiomerically enriched forms. The direct cyclization of enyne substrates to form new C-C or C-heteroatom bonds proved to be an efficient atom and step economy approach for the synthesis of bicyclic or tricyclic compounds. The well-known cyclizations of 1,6- and 1,5-enynes into bicyclic compounds are one of the most powerful examples. Moreover, during the last few years, our group developed several series of chiral platinum or gold pre-catalysts which exhibit excellent catalytic activity, diastereoselectivity and enantioselectivity in the cyclization of enyne substrates.As far as we know, gold complexes with central, axial and helical chirality exhibited excellent results both in terms of catalytic activity and enantioselectivity. However, the planar chirality has been rather neglected so far in the gold promoted enantioselective cyclizations. Although some planar chiral gold complexes (mainly based on the ferrocene structure) have been reported in recent years, high enantioselectivity proved particularly difficult to obtain. In order to extend the potential applications of the planar chiral gold complexes, we have synthesized two new family of gold complexes with planar chirality and applied them in the cycloisomerization of 1,5-enynes and 1,6-dienynes. Finally, with several families of chiral gold complexes (with axial, planar or helical chirality) in hand, we developed a new type of cycloaddition reaction, with excellent catalytic activity and enantioselectivity.This thesis summarizes these studies: i) The chiral monodentate phosphines based on ortho-disubstituted ferrocene units have been prepared and used for the synthesis of gold(I) complexes. These complexes proved to be very active catalysts for the cycloisomerization of 3-hydroxy-1,5-enynes into bicyclo[3.1.0]hexanones. Their high catalytic activity is ascribed to their structural analogy to the biaryl-based Buchwald phosphines. ii) We have also synthesized and characterized new chiral phosphoramidites and demonstrated for the first time the ability of planar-chiral gold(I) complexes to obtain high enantioselectivities in cycloisomerisation reactions. Furthermore, starting from N-tethered prochiral dienynes, the corresponding bicyclo[4.1.0]heptane derivatives, containing three contiguous stereocenters, were obtained in good yields, with a total diastereoselectivity and up to 95% ee. iii) With a number of chiral gold complexes (with axial, planar or helical chirality), an efficient approach for the cycloaddition of cyclopropylenynes has been developed, based on the enantioselective gold catalyzed cycloaddition reaction. This novel method provides an easy access to the enantioselective synthesis of cyclobutanones and the further preparation of chiral tricyclic compounds possessing the skeleton of natural products. We have highlighted axial bis(phosphine)digold(I) complexes which afforded the cyclobutanones with up to 99% enantiomeric excesses in these cyclization reactions
Santori, Pietro Giovanni. « Investigation of electrocatalysts for anion-exchange membrane fuel cells ». Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS129.
Texte intégralThis PhD thesis investigates the synthesis, structural characterization and oxygen reduction reaction (ORR) activity of Fe-N-C catalysts and composites of Fe-N-C and manganese oxides, and their application at the cathode of anion exchange membrane fuel cells (AEMFCs). Compared to proton exchange membrane fuel cells (PEMFCs), where platinum is today needed to reach high performance, AEMFCs hold the promise to reach high performance without precious metals in their catalysts. While Fe-N-C catalysts are currently investigated as an alternative to Pt/C for PEMFC cathodes, they suffer from lower activity and lower durability in the acidic medium of PEMFCs. In contrast, both the ORR activity and stability of Fe-N-C catalysts can be expected to be significantly improved in AEMFC.This PhD work demonstrates the high activity, stability and durability in alkaline medium of Fe-N-C catalysts with atomically-dispersed FeNx sites. They were prepared from a mix of ZIF-8 and iron salt, pyrolyzed in argon (Fe0.5-Ar) and then ammonia (Fe0.5-NH3). The activity was measured in a rotating disk electrode (RDE) and in AEMFC, while the stability was measured in RDE and in operando with mass spectroscopy (ICP-MS) coupled with a scanning flow cell, in both acid and alkaline media. The latter setup was used to measure Fe dissolution in operando. It was evidenced that, in oxygenated acid electrolyte, the iron leaching rate of the most active Fe-N-C catalyst (Fe0.5-NH3) is 10 times faster compared to the less active Fe0.5-Ar. This explains the reduced stability of ammonia-treated Fe-N-C catalysts in operating PEMFC. In contrast, in alkaline medium, very little demetallation was observed even for Fe0.5-NH3. This was correlated with almost unchanged activity after load cycling in RDE. The nature of the active sites was investigated with X-ray absorption spectroscopy, including in operando measurements.Then, to minimize the amount of peroxide species during ORR on Fe-N-C, different manganese oxides were synthesized and their activity for ORR and hydrogen peroxide reduction reaction (HPRR) were evaluated, while operando manganese dissolution was investigated with ICP-MS. It was found that even the most stable Mn-oxide, Mn2O3, leached a significant amount of Mn during ORR in alkaline medium. It was further demonstrated that the Mn leaching is associated with hydrogen peroxide produced during ORR. Composites of Fe0.5-NH3 and Mn-oxides were then investigated for ORR and HPRR. Improved selectivity during ORR was observed for all composites relative to Fe0.5-NH3 alone, but the effect was strongest for Mn2O3.Before investigating such catalysts in AEMFC, a study on the compatibility between different ORR and/or hydrogen oxidation reaction catalysts (Pt/C, Fe0.5-NH3, PtRu/C, Pd-CeO2/C) and anion exchange ionomers was performed in RDE in 0.1 M KOH. The study identified issues between the investigated ionomers and catalysts having low metal contents on the carbon support (Fe0.5-NH3, Pd-CeO2/C).The catalyst Fe0.5-NH3 and its composite with Mn2O3 were then investigated in AEMFC with an ethylene-tetrafluoroethylene ionomer. Both cathode catalysts reached a current density of ca 80 mA cm-2 at 0.9 V, with relatively low loading of 1.0-1.5 mg catalyst·cm-2. The peak power density with H2/O2 reached 1 W cm-2 at 60°C with a low density polyethylene AEM and 1.4 W cm-2 with high density polyethylene AEM at 65°C. By comparison, a current density of ca 70 mA cm-2 at 0.9 V and peak power density of 1.5 W cm-2 was reached with 0.45 mgPt cm-2 at the cathode (40 wt% Pt/C) with low density polyethylene AEM at 60°C. A durability test of 100 h at 0.6 A cm-2 in air showed good stability of the Fe0.5-NH3 catalyst.In conclusion, this work highlights the promising application of Fe-N-C catalysts at the cathode of AEMFCs for replacing precious metal catalysts