Experimental measurement of fuel properties are expensive, require sophisticated instrumentation and are time consuming. Mathematical models and approaches for predicting fuel properties can help reduce time and costs. A new approach for characterizing petroleum fuels called the functional group approach was developed by disassembling the innumerable fuel molecules into a finite number of molecular fragments or ‘functional groups’. This thesis proposes and tests the following hypothesis, Can a fuels functional groups be used to predict its combustion properties? Analytical techniques like NMR spectroscopy that are ideally suited to identify and quantify the various functional groups present in the fuels was used. Branching index (BI), a new parameter that quantifies the degree and quality of branching in a molecule was defined. The proposed hypothesis was tested on three classes of fuels namely gasolines, diesel and heavy fuel oil. Five key functional groups namely paraffinic CH3, paraffinic CH2, paraffinic CH, naphthenic CH-CH2 and aromatic C-CH groups along with BI were used as matching targets to formulate simple surrogates of one or two molecules that reproduce the combustion characteristics. Using this approach, termed as the minimalist functional group (MFG) approach surrogates were formulated for a number of standard gasoline, diesel and jet fuels. The surrogates were experimentally validated using measurements from Ignition quality tester (IQT), Rapid compression machine (RCM) and smoke point (SP) apparatus. The functional group approach was also employed to predict research octane number (RON) and motor octane number (MON) of fuels blended with ethanol using artificial neural networks (ANN). A multiple linear regression (MLR) based model for predicting derived cetane number (DCN) of hydrocarbon fuels was also developed. The functional group approach was also extended to study heavy fuel oil (HFO), a viscous residual fuel that contains heteroatoms like S, N and O. It is used in ships as marine fuel and also in boilers for electricity generation. 1H NMR and 13C NMR measurements were made to analyze the average molecular parameters (AMP) of HFO molecules. The fuel was divided into 19 different functional groups and their concentrations were calculated from the AMP values. A surrogate molecule that represents the average structure of HFO was then formulated and its properties were predicted using QSPR approaches.

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Yes / Steady state and dynamic modelling and simulation of catalytic reforming unit of Kaduna Refining & Petrochemical Company, NNPC (Nigeria) was carried to find out the behaviour of the reactions under both steady and unsteady state conditions. The basic model together with kinetic and thermodynamic parameters and properties were taken from the literature but is developed in gPROMS (an equation oriented modelling software) model building platform for the first time rather than in MATLAB or other modelling platform used by other researchers in the past. The simulation was performed using gPROMS and the predictions were validated against those available in the literature. The validated model was then used to monitor the behaviour of the temperature, concentrations of parafins, naphthenes and aromatics with respect to both time and height of the reactor of the industrial refinery of Nigeria. Hydrogen yield, Research octane number (RON) and temperature profiles are also reported. The components behave similarly in terms of reactions in the reactors but the time to attain quasi-steady state is different. The results are in good agreement with the industrial plant data.

H2S peut être un gaz dominant dans les réservoirs pétroliers carbonatés. Cependant, les recherches sur l'influence de H2S sur la composition et la stabilité thermique du pétrole restent limitées. Dans cette thèse, les interactions entre les hydrocarbures et H2S ont été étudiées de 310 à 350°C, à 700 bar, par pyrolyse confinée en tubes d'or scellés. La pyrolyse d'une huile non soufrée en présence de H2S ont permis de mettre en évidence une nouvelle voie de formation des composés organiques soufrés dans les pétroles. Les pyrolyses des mélanges n-octane/H2S et alkylbenzène/H2S ont permis de proposer les différentes réactions radicalaires pour la formation des produits soufrés principaux : les thiophène, thiols, thiacycloalcanes, alkyl-thiophènes dans le premier cas ; les thiols aromatiques, alkyl-benzothiophènes dans le second. Les résultats obtenus dans le mélange n-octane/H2S ont permis d'établir et valider un modèle cinétique détaillé. Ce mécanisme a permis de montrer que la pyrolyse n-octane/H2S se déroule en chaînes longues et que H2S a un effet inhibiteur sur la consommation du n-octane aux températures supérieures à 320°C, mais accélère fortement la réaction aux basses températures. Des extrapolations du modèle aux conditions géologiques (150-200°C, 700 bar) montrent que H2S a un effet important sur la composition chimique et la stabilité thermique des hydrocarbures. Le modèle permet aussi d'explorer la réactivité de H2S aux conditions de récupération assistée d'huiles lourdes soufrées (injection vapeur, pyrolyse) ou aux conditions de stockages en réservoir pétroliers déplétés / H2S can be a dominant gas in carbonate petroleum reservoirs. However, researches on the influence of H2S on the oil stability are limited in literature. In this thesis, interactions between hydrocarbons (oils, model compounds) and H2S were studied by confined pyrolysis in gold cells from 310 to 350°C under 700 bar. Results of pyrolysis of oil (free of sulfur) in presence of H2S lead to highlight a new pathway of formation of organic sulfur compounds in oils. Pyrolysis of binary mixtures n-octane/H2S and alkylbenzène/H2S allowed to propose different radical reactions for the generation of main sulfur products, namely, thiophene, thiols, thiacycloalkanes, alkyl-thiophenes in the first case ; thiol-aromatics, alkyl-benzothiophenes in the second. Results obtained in the mixture n-octane/H2S led to construct and validate a detailed mechanistic model. The mechanism shows that pyrolysis of n-octane/H2S occurs in long chain and H2S has an inhibition effect on the consumption of n-octane at temperatures above of 320°C, but accelerate the reaction rate strongly at low temperatures. Extrapolation of the kinetic model to geological temperatures and pressures (150-200°C, 700 bar) shows that H2S can significantly influence the composition and stability of hydrocarbons. It is also proposed to apply the model to study the reactivity of H2S under conditions of enhanced recovery (steam injection, pyrolysis) or of geological storage in depleted petroleum reservoirs

L'engouement aujourd'hui pour la manipulation des propriétés électriques des supraconducteurs moléculaires dans le domaine des matériaux, nous a conduit à installer des gyroscopes au sein du cristal, pour que la propriété dynamique puisse moduler l'environnement électrostatique pouvant déboucher vers un nouvel ordre de charge et des structures ferroélectriques. Une machine moléculaire qui possède un rotor, un axe de rotation et des stators tel que le 1,4-diéthynylbicyclo[2,2,2]octane, a été choisie pour sa particularité à interagir avec la lumière, que l'on organise au sein du solide, sous forme de monocristaux appelés moteurs cristallins. La RMN CP/MAS sur poudre cristalline et monocristal a permis de caractériser le mouvement du rotor. Le développement d'une approche cristalline ajouté à la fonctionnalisation des rotors ont permis leur auto-assemblage et leur installation dans des architectures ouvertes organisées autour de cation métalliques (MOF,PCP,), ce qui a permis l'élaboration de matériaux multifonctionnels, dotés de la fonction dynamique, aux propriétés de conductivité ou de transition spin (SCO-MOF). Finalement, l'étude de systèmes cristallins dynamiques de basse dimentionnalité en optique non linéaire a permis de mettre en évidence le phénomène de photo-pilotage des gyroscopes par la lumière au sein du solide. le développement de systèmes plus élaborés permettra de mieux comprendre ce phénomène afin de l'utiliser dans des applications industrielles.

111f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-04-08T15:24:24Z No. of bitstreams: 1 Dissertação Karla Conceição.pdf: 1315216 bytes, checksum: 9a7555a384ee174d65453856c5c12964 (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-05-09T17:28:53Z (GMT) No. of bitstreams: 1 Dissertação Karla Conceição.pdf: 1315216 bytes, checksum: 9a7555a384ee174d65453856c5c12964 (MD5) / Made available in DSpace on 2013-05-09T17:28:54Z (GMT). No. of bitstreams: 1 Dissertação Karla Conceição.pdf: 1315216 bytes, checksum: 9a7555a384ee174d65453856c5c12964 (MD5) Previous issue date: 2010 / CNPq / A influência do número e ordem de tratamentos de oxidação e redução nas propriedades de catalisadores contendo platina, germânio e/ou rênio, suportados em alumina, foi estudada neste trabalho, visando à sua aplicação na reforma catalítica de nafta de petróleo. Os catalisadores foram preparados pelo método de impregnações sucessivas de soluções metálicas (ácido hexacloroplatínico hexahidratado, (perrenato de amônio e cloreto de germânio), em uma y-alumina comercial. As amostras foram submetidas a tratamentos de oxidação e/ou redução durante a impregnação dos metais, sendo obtidos catalisadores monometálicos, bimetálicos e trimetálicos. Os sólidos foram caracterizados por redução termoprogramada, dessorção de piridina a temperatura programada, espectroscopia fotoeletrônica de raios X, espectroscopia no infravermelho com transformada de Fourier de monóxido de carbono adsorvido e avaliadas na desidrogenação do cicloexano e isomerização do n-hexano. Observou-se que o comportamento redutor dos sólidos bimetálicos e trimetálicos é afetado pelo método de preparação. A etapa de oxidação favoreceu uma interação mais forte entre os metais nas amostras bimetálicas contendo germânio e platina, enquanto a redução favoreceu uma interação mais fraca entre os metais e uma interação mais forte do óxido de germânio com o suporte. Nas amostras bimetálicas contendo platina e rênio, a etapa de redução seguida de oxidação favoreceu a interação entre os metais, enquanto nos sistemas trimetálicos a interação entre os metais foi favorecida por pelo menos uma etapa de redução. Foi observado também que o tratamento de oxidação favoreceu a formação de sítios de acidez mais fraca, nos catalisadores formados por platina e germânio e o inverso ocorreu com as amostras bimetálicas contendo rênio. Em todos os casos, o tratamento de redução, conduzido no final da preparação, levou a uma diminuição na quantidade de sítios ácidos fortes, com maior formação de sítios ácidos fracos ou de acidez moderada. Os tratamentos térmicos de oxidação e redução durante a preparação dos catalisadores, conduziram a diferentes distribuições dos metais na superfície dos sólidos, devido às diferentes interações entre eles, que causaram diferentes migrações no sólido. A presença do germânio diminuiu a densidade eletrônica da platina em relação ao catalisador monometálico de platina, enquanto o rênio possui um efeito inverso. Nas amostras bimetálicas contendo rênio, em que foi feito apenas o tratamento de redução ou oxidação, foi observada a formação de sítios com maior deficiência eletrônica que o sólido que sofreu os dois tratamentos. A atividade na desidrogenação do cicloexano foi mais baixa nos catalisadores contendo germânio, ocorrendo o inverso naqueles contendo rênio. Em uma tendência geral, a atividade desidrogenante dos sítios metálicos foi diminuída nos sólidos em que se realizou a redução da platina antes da etapa de oxidação ou não foi feita a redução. Entre os catalisadores trimetálicos, a amostra que sofreu três etapas de oxidação e uma de redução apresentou a atividade mais elevada. Na isomerização do n-hexano, as duas etapas de oxidação favoreceu a atividade da amostra de platina e germânio, o que foi atribuído à formação de sítios adequados para as reações de isomerização. Este catalisador também produziu a maior quantidade de benzeno / Salvador

Carbonaceous deposits accumulate on the majority of the inner surfaces of internal combustion engines. The presence of these deposits is known to cause impaired engine performance. This is manifested as increased knocking, higher fuel consumption, higher emissions and other adverse effects. One of the proposed mechanisms for this behaviour is the adsorption and desorption of fuel components in the pores within the deposit. The porous nature of the deposits promotes this behaviour, altering the fuel composition and reducing the amount of fuel entering the combustion chamber. Previous research in this area was aimed at determining the porous structure of the deposits by combining experimental procedures with molecular simulations to investigate adsorption interactions with fuel components. Using a characterisation procedure regularly applied to activated carbons, a molecular model was developed that was able to provide new insights into the deposit structure. This model enabled predictions to be made for the single-component adsorption of normal heptane and iso-octane, two species commonly used as a gasoline reference fuel. Results showed significant adsorption of both species, and highlighted the impact of adsorption into the internal porous structure of the engine deposits. The aim of this thesis is to further investigate adsorption in engine deposits by expanding the studies to more complex systems. We develop a model to predict the adsorption of normal heptane, iso-octane, toluene and their mixtures in deposits of different origins and under different conditions. The study of multi-component mixtures provides insight into selectivity effects of adsorption under confinement, while at the same time bringing the systems under consideration closer to realistic multi-component mixtures that better represent fuel blends. The study also considers for the first time adsorption of aromatic species, both as a single component and in mixtures, since aromatics have a high presence in gasoline fuel. We explore the influence of molecular structure of adsorbing species, composition of the bulk mixture and temperature on the uptake and selectivity behaviour of the engine deposits. We demonstrate that under equilibrium conditions, deposits can adsorb substantial amounts of hydrocarbon species of all types. However, selectivity behaviour in engine deposits was found to be a subtle and complex property, highly sensitive to both pore size and system pressure.

Dans le domaine des machines moléculaires, la recherche d'un système produisant un mouvement orienté fait l'objet d'intenses recherches. Des résultats ont déjà été obtenus en ce sens mais n'exploitant pas le mouvement brownien comme le font les systèmes trouvés dans la nature comme la myosine. Nous proposons donc la synthèse d'une roue à rochet avec pour but de mimer ce phénomène, si besoin avec une activation de faible énergie. La première partie de ce travail a consisté en la conception par modélisation de l'équivalent synthétique d'une roue à rochet, basiquement constituée d'une roue crantée et d'un cliquet en vue d'étudier si une telle molécule pourrait produire une rotation orientée. Ce système est constitué d'un motif bishomoinositol fonctionnalisé en tant que roue et d'un cycloadduit de l'anthracène comme cliquet, liés par des bras espaceurs. La synthèse d'un système modèle dans lequel un motif bicyclo[2.2.2]octane joue le rôle de roue simplifiée a été menée afin de valider les différentes stratégies de synthèse. A cette occasion, une méthode alternative de la synthèse du diacide bicyclo[2.2.2]octanoïque a été mise au point ainsi qu'une méthodologie d'estérification compatible avec cet acide ainsi que le diacide 9,10-anthracènedioïque. Nous sommes ainsi parvenus à obtenir le produit de macrolactonisation, avec de possibles application comme roue de nanovéhicules. La synthèse du modèle a été l'occasion de pointer certaines impossibilités synthétiques au niveau des espaceurs (éthers, amides, triazoles, tétrazoles, alcènes) dans le système original. Un nouveau travail de modélisation a permis d'aboutir à une cible accessible synthétiquement conservant le comportement de roue à rochet. Dans cette optique, la synthèse du bishomoinositol fonctionnalisé par des acides en tête de pont a été entreprise par une première voie incluant ces groupements au départ de la synthèse, une seconde voie introduisant ces groupements en fin de séquence. / In the field of molecular machines, systems producing an oriented motion have been intensely looked for. Results, obtained toward this goal, do not exploit Brownian motion whereas it happens in natural systems such as myosin. Hereby we propose the synthesis of a molecular ratchet aiming to mimic this phenomenon or to be able to act as a molecular motor through low energy activation. The first part of this work consisted in the design by modelisation of a synthetic equivalent of a ratchet, basically consisting of a toothed wheel and a pawl. This study aim at determining if such a molecule could produce an oriented motion by simple Brownian motion. This system is consisting of a functionalized bishomoinositol moiety as the wheel and a cycloadduct of anthracene as the pawl, linked by spacers allowing the adjustment of the energy barriers. The synthesis of a model where a bicyclo[2.2.2]octane moiety plays the role of a simplified wheel has been conducted in order to validate various synthetic strategies. This gave the opportunity to develop an alternative method of the synthesis of the bicyclo[2.2.2]octanedicarboxylic diacid as well as an esterification methodology compatible with the bulkiness or low solubility of both partners. The macrolactonization product could be obtained and opens some possible applications as nanovehicle wheels. The synthesis of the model was the occasion to highlight synthetic limitations concerning the spacers (ethers) in the original system. A new series of targets taking into account the synthetic restrictions while keeping the ratchet behavior were designed. The discovery of another synthetic difficulties (amides, triazoles, tetrazoles and alkenes) yielded a single refined target. Toward this goal, the synthesis of the bishomoinositol functionalized in the bridgehead position was engaged in a first pathway including these functions at the beginning of the synthesis, the second way introducing them on the bishomoinositol at the end of the sequence.

La quinocarcine appartient à la famille des tétrahydroisoquinoléines, produits naturels qui constituent de puissants agents cytotoxiques et possèdent de nombreuses activités biologiques telles qu'antitumorales et antibiotiques. Son intérêt biologique ainsi qu'un faible rendement d'extraction du milieu naturel ont fait d'elle une cible attrayante en synthèse organique. Dans le but d'effectuer la synthèse totale de la quinocarcine, plusieurs stratégies ont été envisagées pour construire la structure tétracyclique ABCD. Ces stratégies se sont appuyées sur différentes étapes clé comme des réactions de Pictet-Spengler ou des cyclisations de type Mannich, mettant en jeu une espèce N-acyliminium ainsi que différents types de nucléophiles, à savoir un malonate, un énamide et un éther d'énol silylé. La première stratégie qui utilise en motif malonate comme nucléophile pour réaliser la réaction de type Mannich n'a pas permis de construire le motif diaza-bicyclo-[3.2.1]-octane. Cependant, la synthèse énantiosélective de tétrahydroisoquinoléines fonctionnalisées a pu être effectuée de façon efficace. D'autre part, une voie de synthèse asymétrique de l'acide -carboxy-L-glutamique (L-Gla) a été mise au point au laboratoire. La deuxième stratégie que nous avons étudiée fait intervenir des nucléophiles de type énamides. Nous avons rencontré, là encore, des problèmes de réactivité. Malgré nos efforts, il n'a pas été possible d'activer sans dégradation la fonction énamide pour généner le motif pyrrolidine souhaité par addition sur un N-acyliminium. Néanmoins, une méthodologie de synthèse utilisant une oléfination de Wittig a été développée pour préparer des acides α-aminés comportant le motif énamide en β. La troisième stratégie utilise un éther d'énol silylé comme partenaire nucléophile pour réaliser la réaction de Mannich. Un intermédiaire clé tricyclique comportant le motif éther d'énol silylé a pu être synthétisé. Des essais sont actuellement en cours enfin de réaliser l'étape déterminante de cyclisation.