Dissertationen zum Thema „Catalyse moderne“

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

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

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

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

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

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

Proposition d'un nouveau modele de surface active grace a l'utilisation de la rmn du cobalt 59 et a l'activite des sulfures de tous les metaux de transitions. Proposition d'un nouveau modele pour l'empoisonnement des catalyseurs hds par le vanadium

Recherche de nouveaux catalyseurs pour les reactions d'epoxydation d'olefines en phase homogene et modelisation d'enzymes a heme comme le cytochrome p-450 ou la catalase. Isolement de complexes porphyriniques ayant l'anion hypochlorite comme coordinat axial. Activite catalytique de la phtalocyanine de fer associee a l'hydrogenopersulfate de potassium. Etude de l'activite catalytique de modeles chimiques de la catalase

Polymerisation du styrene et de l'hexene-1 en presence de catalyseurs a base de titane, sans organoaluminique, contenant ou non du chlorure d'aluminium et par du chlorure de magnesium. Influence d'addition de benzoate d'ethyle

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This research (The artistic act as catalysis: experiences in the body and dance) reflects upon the intensive dimension of the artistic act. It seems to me that art (the creative state) can catalyze and intensify potential for change, open up areas of movement and promote new connections and potential . The sensitivity promoted by this act should be different from that organizing our everyday experience; through this reorganization, transmutation or metamorphoses comes its political potential. Catalyze: a term borrowed from Chemistry imbued with a special meaning. Existential-poetic catalysis is how Guattari denominates the process of the search for paths to singular new existential territories, not serialized. To give shape to my reflections I interviewed the seven performers-creators of Cia. Nova Dança 4, a dance-theatre company from São Paulo. I was interested in grasping through the traces of the pulsating nature, the collective movements of the appropriation and invention of life which favour the production of singular existences. Why is art produced and consumed ? What ecstasy is this, that of poetry? I found two responses: the Russian psychologist Vygotsky s (art as a social technique of feelings that operates catharsis) and Deleuze and Guattari s (aesthetics in the relationship between forms and forces that can catalyze the invention of new existential territories). Because of the chosen theoretical framework it is not possible to talk about art without talking about the body and the need to return to it in that which is most singular: the porous body which is affected by encounters and partings in the world. Perhaps some experiences in contemporary dance can invent and construct bodies open to other forces and intensities Body without Organs. Elements that emerged during the construction of this framework led me to reflections of a more sociological nature: the institutional aspects of dance, formation of artistic groups and being an artist today . I also review the history of dance in the West and the principal elements of Contact Improvisation (in dialogue with Michel Foucault s reflections on power/body). Finally, I recover Vygotsky s conception of catharsis with a view to broadening the notion of catalysis. I understand that the discussion of the definition and use of these two terms, as well as their reorganization, can increase their power of creation-action (especially in the draw of the performing arts in question)
Nesta pesquisa, reflito sobre a dimensão intensiva do fazer artístico: pareceme que a arte (o estado criativo) pode catalisar e intensificar potências de mudança, abrir zonas de passagem e florescer novas conexões e potências . O sensível que ela produz deve ser diferente daquele que organiza nossa experiência cotidiana; dessa reorganização, transmutação ou metamorfose, sua potência política. Catalisar: termo emprestado da Química com um sentido especial. Catálise existencial-poética é como Guattari denomina o processo de busca por caminhos para novos territórios existências singulares, não serializados. Para dar forma às minhas reflexões, entrevisto os(as) sete intérpretes-criadores(as) de uma companhia de dança-teatro paulistana, a Cia. Nova Dança 4. Interessa-me apreender, através dos vestígios da natureza pulsativa, os movimentos coletivos de apropriação e invenção da vida que favoreçam a produção de existências singulares. Para quê se faz e se consome arte? Que êxtases são esse, os da poesia? Encontro dois caminhos de respostas: o do psicólogo russo Vygotsky (arte como técnica social do sentimento que opera a catarse) e o de Deleuze e Guattari (estética na relação entre formas e forças que pode catalisar a invenção de novos territórios existências). Pelo referencial teórico escolhido, não há como falar de arte sem falar de corpo. Pode-se falar na necessidade de se retomar o corpo naquilo que é mais próprio: corpo poroso, afetado pelos encontros e desencontros no mundo. Talvez algumas experiências da/na dança contemporânea possam inventar e construir corpos abertos a outras forças e intensidades Corpo sem Órgãos. Elementos que emergiram durante a construção dessa teia levaram-me a reflexões de cunho mais sociológico: aspectos institucionais da dança, da formação de grupos artísticos e do ser artista hoje . Também recupero a história da dança no Ocidente e os elementos constitutivos da dança Contato Improvisação (em diálogo com reflexões de Michel Foucault sobre poder/corpo). Para terminar, resgato a concepção de catarse , de Vygotsky, em busca de uma ampliação da noção de catálise. Entendo que a discussão da definição e uso desses dois termos, bem como sua reorganização, pode ampliar seu poder de criação-ação (em especial com o enredar nas artes cênicas em foco)

La preparation de complexes metalliques, modeles des sites actifs de la superoxyde dismutase ou de la catalase, est un enjeu important dans le domaine des therapeutiques antioxydantes. Dans cette optique, differentes series de ligands, de structures ouvertes, macrocycliques ou macrobicycliques, ont ete synthetisees et leurs complexes du cuivre (ii) ou du fer (iii) ont ete etudies. Dans une premiere partie, la complexation du cu(ii) par onze ligands macrocycliques ou a chaine ouverte, a quatre sites de coordination azotes ou soufres (n#2s#2, n#3s), a ete etudiee par differentes methodes spectroscopiques (uv-visible, rpe) et des mesures electrochimiques ont ete effectuees. L'influence de la taille des cycles chelatants et de la nature des atomes donneurs sur le potentiel redox et sur la geometrie des complexes a ainsi ete mise en evidence. Certains complexes soufres possedent une bonne activite sod in vitro, mais la perdent en presence de serumalbumine. Dans une seconde partie, les strategies de preparation de modeles synthetiques non porphyriniques de catalase, pouvant complexer le fer soit sous forme d'acetylacetonates, soit sous forme de macrobicycles tetrazazote, sont decrites. De nombreuses syntheses originales ont ete realisees: protection-deprotection de 1,3-dicetones, double condensation de reactifs de wittig fonctionnalises, essais de macrobicyclisation avec ni#2#+ comme gabarit. Une serie de cinq complexes fe(iii)-bisacac a ete identifiee par spectrometrie de masse (fab) et leur stoechiometrie verifiee par spectrophotometrie uv-visible. Leur formation en absence de base semble la plus favorable pour l'obtention de complexes mononucleaires. L'activite catalase de ces complexes s'est averee assez faible

Syftet med detta arbete har varit att undersöka om berättelsen kan fungera som katalysator för elevernas reflektion över sig själva och deras situation i ett postmodernt samhälle. Väsentliga frågor i sammanhanget blev dels huruvida de själva kunde bli medvetna om och reflektera över sina egna och andras strategier i en sådan omfattande social omvandling. Ett sådant fenomen som kom i fokus var vårt behov av ytliga statussymboler.Det i grunden kvalitativa arbetet bygger på tre synvinklar och tillika källor. För det första, mig själv som oundvikligt subjektivt filter; för det andra eleverna och för det tredje, mediala källor som på olika sätt har kunnat användas i sammanhanget.Under arbetets lopp har jag kommit fram till att arbetets informativa, reflektiva och diskursiva processer i sig utgjorde ett lika intressant material som slutsatserna.
The purpose of this work has been to examine the function of storytelling as an induct-ive way to develop self reflection and environmental awareness of the students. Key subjects have been if they could be attentive to the very reflective process itself and to the strategies we apply, when to cope with dynamic changes as those of the postmodern society. Also the possibility to find basic explanations, to specially one of these strategies – one that has been more and more frequently used – became a pursuit in this work. The phenomenon in mind is our seemingly growing demand for “superficial valuables”.This work is basically qualitative. Three perspectives – as well as sources of inform-ation – have been developed through the process of this work: firstly, the inevitably subjective experiences of my own; secondly, the students; and thirdly, different forms of applicable public media. Especially the contribution from the students can’t be overstated. Initially it was them who made me aware of the phenomenon, described above. Moreover they gave input, partly through the literature seminar and the related discussion, partly through a minor enquiry consisting of a few but fundamental questions connected to the matter of “wealth” and “ability”.Quite early during the progression of this work I came to an understanding that the informative, the introspective and the communicative processes of the work itself constituted a most interesting substance. Hence, I made a more careful attempt to describe this development and my thoughts connected to it, rather than giving too much focus on the aftermath. Retrospectively seen, it presents somewhat self-evident answers of the two initial questions above. Yes, storytelling might work as a complement to more radical experiences of the real life. It can be used as a key to existential reflection in an urban security-devoting postmodern society. Also obviously, there seem to be more profound explanations to our quest for superficial valuables – needs beyond the very appeal. They could be connected to the natural instinct of individual survival through real or “illusory” acceptance and irreplaceability within one or more collective social orders – in short, the importance of being important.

Etude structurale de substances pouvant intervenir en tant que catalyseurs ou conducteurs electriques dans le monde industriel, dans le cadre de trois modeles : modele de l'atome cl mu -ponsteur co::(3) cl(c::(2)f::(3)o::(2))::(3)(so::(4))(c::(4)h::(10)o::(2))::(3) et mn::(4)cl::(4)(c::(2)f::(3)o::(2))::(4)(c::(4)h::(10)o)::(6), modele de l'ion tribromure dans des composes organiques et modele de l'iodure simple (iodures organiques comportant des dications diazoniatricycliques c::(14)h::(28)n::(2)**(2+). 2i**(-) et c::(15)h::(30)n::(2)**(2+). 2i**(-) et de l'ion iodoargentate (ag::(4) i::(8)**(4-). 2c::(15)h::(30)n::(2)**(2+))

Research Doctorate - Doctor of Philosophy (PhD)
A laboratory scale process for catalytic partial methane oxidation to methanol and derivatives by N₂O over Fe-based catalysts in a continuous operation mode at moderate temperatures was constructed. Examination of the partial methane oxidation to methanol over Fe-ZSM-5 catalysts at moderate temperatures showed that methanol and formaldehyde were produced at a temperature range from 275 °C to 400 °C with selectivity decreasing with increasing temperature. Incorporation of 0.1 wt% iron to H-ZSM-5 promoted methane and N₂O conversion, as well as the selectivity to C1-oxygenates. Further loading of iron enhanced methane conversion via complete oxidation. With an increase in the CH₄/N₂O ratio, selectivity of both carbon oxides and C1-oxygenates decreased, while the selectivity of ethylene showed an opposite trend. In addition, a relatively high GHSV elevated selectivity to desired products. In order to explore the correlation of structure properties of zeolites to active sites for methanol formation, activity and selectivity over Fe-ZSM-5, Fe-Beta and Fe-FER catalysts were studied at 350 °C for the catalytic partial oxidation of methane. Ammonia adsorption data suggested that among the studied zeolites, H-FER zeolite contained the highest concentration of framework Al atoms which are essential for the formation of active extra-framework Fe species. Fe-FER catalyst contained more active sites for N₂O conversion in comparison to Fe-Beta and Fe-ZSM-5 catalysts, as demonstrated by H₂-TPR profiles and IR spectra of NO adsorbed on the Fe zeolites. The catalytic activity studies showed that Fe-FER was the most active catalyst based on methane and N₂O conversion, and displayed the highest selectivity to C₁-oxygenates and dimethyl ether (DME), while Fe-ZSM-5 obtained the highest selectivity to ethylene among the three catalysts. Fe-ZSM-5 was found to deactivate significantly due to coke formation. Fe-FER catalysts prepared by incipient wetness impregnation (IMP), liquid ion exchange (IE) and solid state ion exchange (SSIE) methods were studied at 350 °C. UV-vis spectra indicated that the main component present in Fe-FER-IMP, Fe-FER-IE and Fe-FER-SSIE was isolated Fe species, dimeric Fe species and oligomeric iron oxides clusters, respectively. The active oxygen sites for the selective conversion of methane were identified by a TPR feature at 220 °C. This sites were also characterised by an infrared band observed at 1872 cm⁻¹ and 1892 cm⁻¹ upon adsorption of NO. The correlation of the area of the unique reduction peak in the H-TPR profiles and the area of a band at 1892 cm⁻¹ in the IR spectra of NO adsorption on the catalysts suggested that the active sites for N₂O decomposition were binuclear Fe species, and Fe-FER-SSIE contained the largest number of active Fe species among the three catalysts. The activity test showed that Fe-FER-SSIE obtained the highest N₂O decomposition at 250 °C but Fe-FER-IE achieved the highest N₂O conversion at elevated temperatures due to the greater likelihood of transformation from active oxygen species to oxygen molecules over Fe-FER-IE. Selectivity to desired products (methanol, formaldehyde, DME and ethylene) over Fe-FER-IMP, Fe-FER-IE and Fe-FER-SSIE was 12.5%, 16.5% and 19.8% (coke took into account), respectively. Formation of active oxygen species from N2O over Fe-FER catalyst prepared by SSIE method at moderate temperatures was studied using spectroscopic and solid characterisation techniques including H₂-TPR, N₂O-TPD and in situ FTIR. These bands observed at 1872 cm⁻¹ and 1892 cm⁻¹ in IR spectra of NO adsorption on catalyst were NO stretching vibrations of NO adsorbed on iron oxygen clusters, present in the zeolite cages and responsible for selective oxidation. It was shown that these oxidised clusters reacted with methane to form oxygenates but at higher temperatures formed molecular oxygen. IR Bands of surface methoxy groups were observed in significant concentration in the FTIR spectra and were suggested to be intermediate species of the selective oxidation of methane. Studies using continuous reactor demonstrated that co-feeding of methane and N₂O promoted generation of desired products from methane conversion by N₂O over Fe-FER catalyst can be enhanced by optimizing the feed ratio of CH₄/N₂O.

Transition metal interface effects of on the crystallization of carbon and silicon were investigated. The graphitization of carbon was studied by ion beam sputter deposition of atomic carbon onto a nickel surface at temperatures ranging from room temperature to 550 °C. The resulting films were characterized by X-ray photoelectron spectroscopy, nuclear reaction analysis combined with Rutherford backscattering spectrometry, Raman spectroscopy and transmission electron microscopy. A temperature-induced and a nickel-induced effect on the graphitic ordering is demonstrated. The carbon films showed a two layered structure: directly on the nickel surface up to 8 monolayers of graphitic carbon, further deposited carbon formed less ordered structures, preferably perpendicular to the surface. The results are discussed on the basis of hyperthermal atom deposition, surface diffusion, metal-induced crystallization and dissolution-precipitation. The analysis points to a dominating role of surface diffusion-assisted crystallization in the carbon ordering process. The kinetics of silver-induced crystallization of amorphous silicon were studied in a series of isothermal annealing experiments at 350 °C, 400 °C, 450 °C and 500 °C. The annealing process was monitored in situ employing Raman spectroscopy and Rutherford backscattering spectrometry from which time resolved information on the phase transformation and hence the kinetics are obtained. The grain structure of the crystallized silicon film was investigated with optical and scanning electron microscopy which reveals grain diameters of 5 to 8 µm. The small scale crystallinity was measured with X-ray diffraction and crystal domain sizes from 20 to 50 nm were observed. The phase transformation kinetics are discussed based on the Johnson-Mehl-Avrami-Kolmogorov theory. The analysis points to a two-dimensional, diffusion limited process with fast Avrami-type nucleation and an activation energy of 0.8 eV/at.:Contents 1. Introduction 2. Metal-Induced Crystallization 2.1. Introduction and State of the Art of Metal-Induced Crystalliza-tion 2.2. Thermodynamics of Metal-Induced Crystallization 2.3. Kinetics of Metal-Induced Crystallization 3. Ion Beam Analysis 3.1. Rutherford Backscattering Spectrometry 3.2. Nuclear Reaction Analysis 4. Raman Spectroscopy 4.1. Light Scattering in Solids 4.2. Theory 4.2.1. The Raman Spectrum of Graphitic Carbon 4.2.2. The Silicon Raman Spectrum 5. The Cluster Tool at the Ion Beam Center 5.1. General Concept 5.2. Sputtering Chamber 5.3. The Environmental Chamber 5.4. The Analysis Chamber 5.5. The Ion Beam Analysis Chamber 5.5.1. The Experimental Setup 6. The Carbon Nickel System 6.1. Experimental Details 6.1.1. Film growth 6.1.2. Characterization 6.2. Results 6.3. Discussion 7. The Silicon Silver System 7.1. Experimental 7.1.1. Film Preparation 7.1.2. In Situ Raman Spectroscopy 7.1.3. In Situ Rutherford Backscattering Spectrometry 7.2. Results 7.2.1. Raman Spectroscopy 7.2.2. Rutherford Backscattering Spectrometry 7.2.3. X-ray Diffraction 7.2.4. Optical and Scanning Electron Microscopy 7.3. Discussion 8. Conclusion and Outlook A. Appendix A.1. Spectroscopic Lineshapes A.1.1. The Lorentzian Lineshape A.1.2. The Breit-Wigner-Fano Lineshape A.1.3. The Doniach-Sunjic Lineshape A.1.4. The Gaussian Lineshape A.1.5. The Voigt Lineshape A.2. Statistcial Distribution Functions A.2.1. The Gamma Distribution Bibliography
Der Einfluss von Übergangsmetallkontaktflächen auf die Kristallisation von Kohlenstoff und Silizium wurde untersucht. Dazu wurde Kohlenstoff bei Temperaturen von Raumtemperatur bis 550 °C auf Nickel mittels Ionenstrahl-Sputtern abgeschieden. Die so erzeugten Filme wurden mit Röntgenphotoelektronen Spektroskopie, Kernreaktionsanalyse kombiniert mit Rutherford Rückstreu Spektrometrie, Raman Spektroskopie und Transmissions-Elektronenmikroskopie charakterisiert. Ein Nickel- und ein Temperatureffekt auf den Graphitisierungsprozess wird nachgewiesen. Die Kohlenstofffilme zeigten einen zweilagigen Aufbau: Direkt auf der Nickeloberfläche bis zu 8 Monolagen graphitischen Kohlenstoffs, weiterer abgeschiedener Kohlenstoff bildet weniger geordnete Strukturen, die bevorzugt senkrecht zur Oberfläche ausgerichtet sind. Die Ergebnisse werden auf Basis von hyperthermischer, atomarer Abscheidung, Oberflächendiffusion, Metall-induzierte Kristallisation und Lösung-Ausfällung diskutiert. Die Analysen deuten auf eine dominante Rolle der Oberflächendiffusion im Graphitisierungsprozess hin. Die Kinetik der Silber-induzierten Kristallisation von amorphen Silizium wurde in einer Reihe von isothermalen Temperexperimenten bei 350 °C, 400 °C, 450 °C und 500 °C untersucht. Der Tempervorgang wurde mit in situ Raman Spektroskopie und in situ Rutherford Rückstreu Spektrometrie charakterisiert, wodurch zeitaufgelöste Information über den Phasenübergang und damit die Kinetik gewonnen wurden. Das Gefüge der entstandenen Siliziumschichten wurde mit optischer und Rasterelektronenmikroskopie untersucht, welche Korndurchmesser von 5 bis 8 µm zeigten. Die Kristallinität wurde mit Röntgendiffraktometrie analysiert. Hierdurch wurden Kristallitgrößen von 20 bis 50 nm bestimmt. Die Kinetik des Phasenüberganges wird anhand der Johnson-Mehl-Avrami-Kolmogorov Theorie diskutiert. Dies deutet auf einen zeidimensionalen, diffusionslimitierten Prozess mit schnell abklingender Avrami-Keimbildung hin. Die Aktivierungsenergie wurde zu 0.8 eV/At. bestimmt.:Contents 1. Introduction 2. Metal-Induced Crystallization 2.1. Introduction and State of the Art of Metal-Induced Crystalliza-tion 2.2. Thermodynamics of Metal-Induced Crystallization 2.3. Kinetics of Metal-Induced Crystallization 3. Ion Beam Analysis 3.1. Rutherford Backscattering Spectrometry 3.2. Nuclear Reaction Analysis 4. Raman Spectroscopy 4.1. Light Scattering in Solids 4.2. Theory 4.2.1. The Raman Spectrum of Graphitic Carbon 4.2.2. The Silicon Raman Spectrum 5. The Cluster Tool at the Ion Beam Center 5.1. General Concept 5.2. Sputtering Chamber 5.3. The Environmental Chamber 5.4. The Analysis Chamber 5.5. The Ion Beam Analysis Chamber 5.5.1. The Experimental Setup 6. The Carbon Nickel System 6.1. Experimental Details 6.1.1. Film growth 6.1.2. Characterization 6.2. Results 6.3. Discussion 7. The Silicon Silver System 7.1. Experimental 7.1.1. Film Preparation 7.1.2. In Situ Raman Spectroscopy 7.1.3. In Situ Rutherford Backscattering Spectrometry 7.2. Results 7.2.1. Raman Spectroscopy 7.2.2. Rutherford Backscattering Spectrometry 7.2.3. X-ray Diffraction 7.2.4. Optical and Scanning Electron Microscopy 7.3. Discussion 8. Conclusion and Outlook A. Appendix A.1. Spectroscopic Lineshapes A.1.1. The Lorentzian Lineshape A.1.2. The Breit-Wigner-Fano Lineshape A.1.3. The Doniach-Sunjic Lineshape A.1.4. The Gaussian Lineshape A.1.5. The Voigt Lineshape A.2. Statistcial Distribution Functions A.2.1. The Gamma Distribution Bibliography