Esta Tese descreve a preparação de novos eletrodos modificados (EMs) fazendo uso de um método novo, a deposição de partículas de metais nobres, como níquel, paládio e platina sobre partículas de metais comuns, como cobre e ferro. Este método leva aos denominados EMs mistos, que podem apresentar características diferentes e mais eficientes que os EMs Ni, Pd e Pt já estudados, sendo a principal aplicação nas reações de hidrogenação eletrocatalítica (HEC) de substratos orgânicos insaturados. A preparação dos EMs mistos se inicia pelo recobrimento da superfície do eletrodo de trabalho com um filme polimérico. O polímero usado foi o poli-(éter alílico do ácido p-benzenossulfônico), um filme aniônico com boa estabilidade química e mecânica, que pode fazer troca iônica de seus íons H+ por cátions metálicos. Este filme é preparado por varreduras de voltametria cíclica de uma solução do respectivo monômero, que se oxida eletroquimicamente iniciando a reação química de polimerização. Os metais cobre e ferro são introduzidos ao polímero pelo método de troca iônica/redução eletroquímica, onde o EM é mergulhado em uma solução saturada de um sal de cobre ou de ferro para ocorrer a troca iônica. Em seguida, estes íons são reduzidos eletroquimicamente por varreduras de voltametria cíclica, usando uma faixa de potencial adequada. Para se preparar os EMs mistos, mergulhou-se estes EMs (Cu ou Fe) na solução do banho electroless de níquel, paládio e platina. Por esta metodologia partículas destes metais nobres são depositadas pelo processo de deposição metálica electroless (DME), que faz uso de um agente redutor, hipofosfito de sódio, para reduzir os íons destes metais de forma adequada nos EMs Cu ou Fe e onde se espera obter grande área superficial. Os EMs mistos preparados foram: Cu/Ni, Cu/Pd, Cu/Pt, Fe/Ni, Fe/Pd e Fe/Pt. A caracterização dos metais dos EMs mistos foi feita indiretamente por geração eletroquímica de hidrogênio (GH) de uma solução ácida e diretamente pelas técnicas de Difração de Raios X e Microscopia de Varredura Eletrônica (MEV). O processo de deposição metálica foi investigado por medidas de potencial de circuito aberto, realizadas durante a deposição dos metais nobres que indicou a ocorrência do processo de DME em alguns casos e DG (deposição galvânica) em outros. Devido a alguns resultados do processo de deposição metálica, foi estudado o mecanismo de catalise na deposição direta das partículas de níquel, paládio e platina pela redução química por hipofosfito dos íons correspondentes. Preparou-se EMs Ni, Pd e Pt por dois métodos: troca iônica/redução eletroquímica e troca iônica/redução química catalisada pelo filme. Estes foram caracterizados por GH e utilizando o ácido p-toluenossulfônico como modelo, estudos de espectroscopia na região UV/Vis. foram realizados. Estas medidas comprovaram a catálise, pois os EMs preparados por redução química apresentaram melhores resultados para a GH e as análises de UV/Vis. mostraram a forte ligação existente entre os grupos sulfonatos do polímero e os íons metálicos bivalentes, ligação essencial para ocorrer a catálise do filme. Verificou-se que as partículas dos metais nobres podiam estar sendo depositadas por DME ou por DG seguido de DME, mas que em todos os casos ocorria a deposição causada pela catálise do filme. A reatividade dos EMs mistos foi avaliada por um estudo cinético, onde HECs de alguns substratos orgânicos foram realizadas e acompanhadas por medidas de UV/Vis. durante as reações. Obteve-se a constante de velocidade (k) destas reações, as quais foram comparadas entre si e encontrou-se como o EM misto mais eficiente o Cu/Pt. As ks das reações deste EM foram comparadas com ks de outros EMs de Pt, já estudados em nossos laboratórios. / This thesis describes the preparation of new modified electrodes (MEs) using the method of noble metal particles deposition like nickel, palladium and platinum in the surface of commum metals particles as cooper and iron. This new electrodes were denominated mixed MEs, and can show different caractheristics and present higher efficiency than others already studied, being their principal application in electrocatalytic hydrogenation (ECH) of unsaturated organic substrates. The surface electrode were coated with the polymer poly-(ether allyl p-benzenesulfonic), an anionic film with good chemical and mechanic stability that can undergoes ion exchange of ions H+ by metallic cations. This film is prepared by anodic oxidation of the monomer using voltammetric cycles, producing a cation radical initiador of a chain reaction polymerization. Cooper and iron metals are incorporated in the polymer by ion exchange/ electrochemical reduction; the ME were dipped in saturated solution of cooper or iron salt to produce the ion exchange. The ions are then electrochemically reduced. The preparation of mixed MEs is carried out by electrolessly deposidated Ni, Pd or Pt. This methodology use NaH2PO2, to reduce the metal ions. This procedure deposits Ni, Pd and Pt in the surface of Cu or Fe MEs with an expected higher superficial area. The mixed Cu/Ni, Cu/Pd, Cu/Pt, Fe/Ni, Fe/Pd e Fe/Pt MEs were prepared. The characterization of the MEs metals was made indirectly by electrochemically hydrogen generation from an acid solution (HG) and directly by SEM-EDX and Ray X Diffraction analysis. The metallic deposition process was investigated by open circuit during the deposition of nobles metals that indicate the occurrence of electroless deposition (EMD) process in some cases or spontaneous displacement reaction (galvanic deposition - GD) in others. Despite the two mechanisms related above, a catalytic process would occur. To rut in evidence this third process Ni, Pd and Pt MEs were prepared by two methods: ion exchange/electrochemical reduction and ion exchange/chemical reduction catalyzed by the film. The resulting MEs were characterized by HG and spectroscopy in the UV/Vis. For this last analysis, p-toluenossulfonic acid was used as model and the results proved the catalytic mechanism. UV spectroscopy analysis showed strong bonds between the p-toluenossulfonic and the noble metal salts. So particles of noble metals can be deposited not only by EMD or GD but in all cases occur the deposition by film catalysis too. The reactivity of mixed MEs was done by kinetic study, where ECH of some organic substrates were carried out and monitored by UV/Vis spectroscopy. The constant rate (k) of the reactions was calculated and compared with the others mixed MEs. The ks of this ME were compared with the ks of other Pt MEs, already studied. The more reactive of them was the Cu/Pt ME.

La préparation du caoutchouc naturel hydrogéné (HNR) par réaction avec l'hydrazine et le peroxyde d'hydrogène et le latex de caoutchouc naturel a été intéressée. L’influence de conditions de réaction, types et volume de solvants, volume du  réactionnel, la quantité d’hydrazine et de peroxyde d’hydrogène sur le degré d’hydrogénation du caoutchouc naturel a été étudiée. Le structure et  détermination du degré d’hydrogénation des caoutchoucs naturel hydrogénés a été analysée par  résonance magnétique nucléaire (RMN), transformée de fourier infrarouge (FTIR) et spectroscopie Raman. Un degré d'hydrogénation de 18 % a été obtenu à 1.0 - 2.0 du la molaire de d’hydrazine et de peroxyde d’hydrogène, température optimale de 50°C et le temps de réaction de 24h. Afin d'améliorer le degré d'hydrogénation, des solvants tels que le toluène et le hexane et l'effet de le volume du réactionnel ont été étudiée, ce qui a permis d'obtenir des degrés d’hydrogénation  élevés (proches de 65% avec le toluène). D’autre part, des mesures de tailles de particules de latex ont montré que l’hydrogénation du caoutchouc naturel n’avait pas d’effet sur latex de caoutchouc naturel. Un résultat également intéressant concerne le détermination du taux de gel. Ce gel augmente avec le degré d’hydrogénation, prouvant que des réactions de réticulation ont eu lieu. Néanmoins aucun effet de degré d’hydrogénation sur le température de transition vitreuse n’est détecté. La dureté et viscosités Mooney augmentent, en lien avec l’augmentation du taux de gel. Par ailleurs, la résistance thermique du caoutchouc naturel hydrogéné est considérablement améliorée lorsque le degré d’hydrogénation augmente. Le partie suivante est consacrée à la vulcanisation du caoutchouc. Deux types de réticulation ont été utilisés : au soufre et au peroxyde. Les élastomères HNR réticulés montrent une meilleure résistance à l’ozone et l’UV que le NR réticulé. De plus, cette résistance à l’ozone et l’UV est plus élevée pour le réticulation au soufre, comparée à le réticulation au peroxyde. Une bonne corrélation entre les images de microscopie optique et les résultats des analyses Raman est obtenue. La préparation et l’étude de mélanges HNR/PP obtenus par vulcanisation dynamique en utilisant du peroxyde et du soufre comme agents de réticulation. Un degré d’hydrogénation de 65% a été choisi, et différentes ratio HNR/PP ont été étudiés, et comparés avec des mélanges NR/PP. La morphologie des mélanges a été caractérisée par spectroscopie Raman, ce qui a permis d’obtenir des images cartographie Raman indiquant de façon précise le localisation et la distribution des phases de caoutchouc et de PP.  Une bonne corrélation entre le cartographie Raman et les images de microscopie électronique à balayage (SEM) est obtenue. Ainsi il apparaît que les particules de caoutchouc sont dispersées dans une phase continue de PP, ceci à la fois pour le HNR et le NR. L’étude des propriétés mécaniques a montré que celles-ci étaient gouvernées principalement par le phase continue de PP. / The non-catalytic hydrogenation of natural rubber latex (NRL) was carried out by using diimide generated in situ from the reaction between hydrazine (N2H4) and hydrogen peroxide (H2O2). The effects of mole ratios of [C=C]:[N2H4]:[H2O2], reaction conditions, solvent types, solvent volumes and reaction scale-up on the hydrogenation levels were investigated. Nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and Raman spectroscopic techniques were employed to investigate the chemical structure of the hydrogenated natural rubber (HNRs) and to quantify the hydrogenationlevels. It was found that variations in moles of N2H4 and H2O2 in the range of 1.0-2.0 moles resulted in degrees of hydrogenation in the range of 10-18%. Little improvement in hydrogenation levels of HNRs was obtained when NRL particles were swollen in solvents by which toluene yielded better results than hexane. The increase in toluenevolume resulted in the increase in hydrogenation levels up to 42 %. TEM micrographs revealed that swelling mainly occurred at the surface of NRL particles, implying that hydrogenation reaction confined largely at the surface of NRL particles. After removal of toluene, particle size and particle size distribution of partially hydrogenated NRL remained unchanged. To further improve degrees of hydrogenation, the reaction volume was extended and 65% hydrogenation levels were obtained. Therefore, 14%HNR, 33%HNR, and 65%HNR were successfully prepared under suitable reaction conditions. However, crosslinking and cis-trans isomerization were side-reactions occurring during hydrogenation. Gel and trans contents increased with increasing hydrogenation levels, leading to the increase in hardness of HNRs. Mooney viscosities of HNRs increased with increasing degrees of hydrogenation due to the increased gel contents. Mooney torquerelaxation of NR and HNRs were similar. Thermogravimetric analysis revealed that vi HNRs had greater thermal stability than NR and thermal stability increased with increasing degrees of hydrogenation. HNR vulcanizates were much better resistant to ozone and UV than cured NR. Sulfur-vulcanized rubbers had greater ozone resistance than peroxide-cure rubbers due to less amounts of carbon-carbon double bonds present in rubbers. In addition, modulus at low strain and tensile strength of sulfur-cured rubbers were higher than those of peroxide-cured rubbers, but lower elongation due to higher crosslink densities. Also, modulus at low strain and tensile strength increased with increasing hydrogenation levels of HNRs, in contrast to strain at break. Thermoplastic vulcanizates (TPVs) from blends of HNR and Polypropylene (PP) were prepared via dynamic vulcanization using peroxide and sulfur as curing agents. The effects of blend ratios on mechanical properties of TPVs were investigated. Tensile strength increased with increasing PP portions, but breaking strain decreased. Morphology of TPVs was characterized with Raman mapping and scanning electron microscope (SEM). The phase sizes of crosslinked rubber obtained from both techniques were correlated well.

Neste estudo, foram sintetizados complexos de ródio com aminoácidos e aminoácidos N-protegidos. Os compostos sintetizados foram caracterizados por análise elementar, espectrofotometria nas regiões do infravermelho e ultravioleta-visível, susceptibilidade magnética, ressonância magnética nuclear de próton e calorimetria exploratória diferencial. As técnicas analíticas utilizadas permitiram avaliar a estrutura dos complexos de ródio obtidos. Nos complexos sintetizados com aminoácidos, a ligação ocorreu pelos átomos de nitrogênio do grupamento amina e pelo oxigênio do grupo carboxila, formando anéis quelato de cinco membros, estrutura esta distinta da apresentada por compostos diméricos de ródio (II). Este modo de coordenação típico de carboxilatos de ródio dimérico, foi alcançado fazendo-se o bloqueio do grupamento amino, direcionando assim a coordenação do aminoácido, aos átomos de ródio, através dos dois oxigênios da carboxila. Numa etapa posterior, o grupo protetor foi removido por ataque ácido, tomando o complexo, anteriormente solúvel em solventes apoiares, totalmente solúvel em água, sendo mantida a estrutura de gaiola. Partindo-se dos complexos de ródio (II) sintetizados com aminoácidos N-bloqueados, foram obtidos adutos com o ácido isonicotínico, que se mostraram mais hidrossolúveis do que os complexos iniciais. Os compostos [Rh2(Boc-Gly)4)(I), [Rh2(Boc-L-Ala)4)(II) e seus respectivos adutos com o ácido isonicotínico foram submetidos a ensaios biológicos in vitro, onde foi avaliada a citotoxicidade destes sobre células tumorais K562, U937 e de tumor de Ehrlich. O aduto [Rh2(Boc-L-Ala)4](AIN)2(III) também foi submetido a um ensaio in vivo, de sobrevida. Camundongos portadores de tumor ascite de Ehrlich, tratados com solução do complexo (III), tiveram um aumento significativo de sobrevida, com formação de tumor sólido. Os complexos (I), (II), [Rh2(Boc-L-Val)4)(IV), [Rh2(Boc-L-Leu)4](V) e [Rh2(Boc-D-Phe)4)(VI) foram avaliados quanto ao seu potencial catalítico, em reações de hidrogenação. Os resultados foram expressos em termos de conversão de substrato em função do tempo de reação, número de rotação, freqüência de rotação e curvas TT x TTG. O complexo (I) apresentou atividade semelhante ao acetato de ródio (II), que foi utilizado como complexo de referência. Os demais compostos, (II), (V) e (VI) mostraram-se mais ativos que o acetato de ródio (II), nas reações de hidrogenação de hexeno-1 em etanol. / In this study, rhodium complexes were synthesized using amino acids and N-protected amino acids as ligands. The synthesized compounds were characterized by elemental analysis, IR and UVVis spectroscopy, magnetic susceptibility, proton magnetic nuclear resonance and diferential scanning calorimetry. The used analytical techniques allowed us to evaluate the structure of the obtained rhodium complexes. In the amino acids complexes, the binding occured through nitrogen atoms of the amino group and through the oxygen atom of the carboxyl group, forming chelate rings of five members, being these structures different from those presented by rhodium (II) carboxylates. This coordination mode was achieved protecting the amino group. In a next stage, the protecting group was removed by acid attack, turning the previously soluble in apolar solvents complex, totally soluble in water, being maintained the cage structure. From the N-protected amino acids rhodium (II) complexes synthesized, we obtained the isonicotinic acid adducts, more hydrossoluble than the original complexes. Antitumor activity of rhodium complexes [Rh2(Boc-Gly)4](I), [Rh2(Boc-L-Ala)4](II) and its isonicotinic acid adducts, was evaluated in vitro ( cell cultures K562, U937 and Ehrlich) and the compound [Rh2(Boc-L-Ala)4](AIN)2(III) was also submitted to a in vivo assay. Mices bearing Ehrlich ascite tumor, when treated with complex (III) solution, had a significant increase life span, with formation of solid tumor. The complexes (I), (II), [Rh2(Boc-L-Val)4](IV), [Rh2(Boc-L-Leu)4](V) and [Rh2(Boc-D-Phe)4](VI) were also tested in catalytic hydrogenation reactions. The results were expressed in terms of substrate conversion, turnover number, turnover frequency and TT x TTG curves. The complex (I) presented catalytic activity similar to the rhodium acetate (II), that was used as reference complex. The other compounds, (II), (V) and (I) exhibited improved catalytic behavior compared to rhodium (II) acetate in hydrogenation reactions using 1-hexene as substrate.

Chemical modification is an important way to improve the properties of existing polymers, and one of the important examples is the hydrogenation of nitrile butadiene rubber (NBR) in organic solvent by homogeneous catalysis in order to extend its application. This process has been industrialized for many years to provide high performance elastomers (HNBR) for the automotive industry, especially those used to produce components in engine compartments. In the current commercial process, a batch reactor is employed for the hydrogenation step, which is labor intensive and not suitable for large volume of production. Thus, novel hydrogenation devices such as a continuous process are being developed in our research group to overcome these drawbacks. In order to make the process more practical for industrial application, high concentration polymer solutions should be targeted for the continuous hydrogenation. However, many problems are encountered due to the viscosity of the high concentration polymer solution, which increases tremendously as the reaction goes on, resulting in severe mass transfer and heat transfer problems. So, hydrogenation kinetics in high concentration NBR solution, as well as the rheological properties of this viscous solution are very essential and fundamental for the design of novel hydrogenation processes and reactor scale up. In the present work, hydrogenation of NBR in high concentration solution was carried out in a batch reactor. A commercial rhodium catalyst, Wilkinson’s catalyst, was used with triphenylphosphine as the co-catalyst and chlorobenzene as the solvent. The reactor was modified and a PID controller was tuned to fit this strong exothermic reaction. It was observed that when NBR solution is in a high concentration the kinetic behavior was greatly affected by mass transfer processes, especially the gas-liquid mass transfer. Reactor internals were designed and various agitators were investigated to improve the mechanical mixing. Experimental results show that the turbine-anchor combined agitator could provide superior mixing for this viscous reaction system. The kinetic behavior of NBR hydrogenation under low catalyst concentration was also studied. It was observed that the hydrogenation degree of the polymer could not reach 95% if less than 0.1%wt catalyst (based on polymer mass) was used, deviating from the behavior under a normal catalyst concentration. The viscosity of the NBR-MCB solutions was measured in a rotational rheometer that has a cylinder sensor under both room conditions and reaction conditions. Parameters that might affect the viscosity of the solutions were studied, especially the hydrogenation degree of polymer. Rheological properties of NBR-MEK solutions, as well as NBR melts were also studied for relevant information. It is concluded that the hydrogenation kinetics deviates from that reported by Parent et al. [6] when polymer is in high concentration and/or catalyst is in low concentration; and that the reaction solution (HNBR/NBR-MCB solution) deviates from Newtonian behavior when polymer concentration and hydrogenation degree are high.

The main objective of the present thesis is to deepen the understanding of the mechanisms involved in catalytic growth of carbon nanotubes (CNT) and related processes, such as the catalytic hydrogenation, and to use this knowledge to optimize the experimental approaches in order to gain better control in the synthesis and modification of carbon nanomaterials. Controlled growth of the CNT is achieved using gas-phase prepared catalyst particles (Fe, Co) which serve as individual catalytic nucleation sites in a chemical vapor deposition (CVD) process. These studies highlight that the controlled preparation of catalyst particles is a crucial step in order to control the CNT morphology. The resultant CNT diameter and the CNT density are found to increase with increasing nanoparticle diameter and density, respectively. The number of walls of the CNT also increases with increasing primary catalyst size. The experimentally derived correlations between the particle diameter on one hand and the CNT diameter and the CNT number of walls on the other hand are attributed to an increase of the catalyst's volume-to-surface area ratio with increasing particle size. While the availability of carbon dissolved within the catalyst at the point of nucleation is determined by the catalyst volume, the amount of carbon required to form a cap depends on the surface area of the catalyst particle. Electron microscopy studies of the catalyst/substrate/carbon interfaces of CNT grown from Fe nanoparticles reveal that the CNT walls are anchored to the oxide substrate which contests the general argument that the CNT walls stem from atomic steps at the catalyst. It is argued that after nucleation, the substrate itself provides a catalytic functionality towards the stimulation of ongoing CNT growth, whereas the catalytic activity of the metal particle is more restricted to the nucleation process. Selective hard-magnetic functionalization of CNT tips has been achieved in a plasma-enhanced CVD process. Hard-magnetically terminated CNT, i.e. CNT with a FePt nanoparticle at each tip, are directly grown using FePt catalysts. Fe/Pt thin films with a strongly over-stoichiometric Fe content in the starting catalyst composition yield CNT with a significant number of particles in the hard-magnetic phase. Anisotropic etching of graphite through Co catalyst particles in hydrogen atmosphere at elevated temperatures (i.e. catalytic hydrogenation) is reported. Catalytic hydrogenation is a potential key engineering route for the fabrication of graphene nanoribbons with atomic precision. While in previous studies the etching of zigzag channels was preferred, the present investigations reveal preferential etching of armchair channels, which provides a means to tailor graphene nanostructures with specific edge termination. Further, detailed morphological and structural characterization of the Co particles provide insight into the hydrogenation mechanism which is still a matter of controversy.

Chemical modification is an important way to improve the properties of existing polymers, and one of the important examples is the hydrogenation of nitrile butadiene rubber (NBR) in organic solvent by homogeneous catalysis in order to extend its application. This process has been industrialized for many years to provide high performance elastomers (HNBR) for the automotive industry, especially those used to produce components in engine compartments. In the current commercial process, a batch reactor is employed for the hydrogenation step, which is labor intensive and not suitable for large volume of production. Thus, novel hydrogenation devices such as a continuous process are being developed in our research group to overcome these drawbacks. In order to make the process more practical for industrial application, high concentration polymer solutions should be targeted for the continuous hydrogenation. However, many problems are encountered due to the viscosity of the high concentration polymer solution, which increases tremendously as the reaction goes on, resulting in severe mass transfer and heat transfer problems. So, hydrogenation kinetics in high concentration NBR solution, as well as the rheological properties of this viscous solution are very essential and fundamental for the design of novel hydrogenation processes and reactor scale up. In the present work, hydrogenation of NBR in high concentration solution was carried out in a batch reactor. A commercial rhodium catalyst, Wilkinson’s catalyst, was used with triphenylphosphine as the co-catalyst and chlorobenzene as the solvent. The reactor was modified and a PID controller was tuned to fit this strong exothermic reaction. It was observed that when NBR solution is in a high concentration the kinetic behavior was greatly affected by mass transfer processes, especially the gas-liquid mass transfer. Reactor internals were designed and various agitators were investigated to improve the mechanical mixing. Experimental results show that the turbine-anchor combined agitator could provide superior mixing for this viscous reaction system. The kinetic behavior of NBR hydrogenation under low catalyst concentration was also studied. It was observed that the hydrogenation degree of the polymer could not reach 95% if less than 0.1%wt catalyst (based on polymer mass) was used, deviating from the behavior under a normal catalyst concentration. The viscosity of the NBR-MCB solutions was measured in a rotational rheometer that has a cylinder sensor under both room conditions and reaction conditions. Parameters that might affect the viscosity of the solutions were studied, especially the hydrogenation degree of polymer. Rheological properties of NBR-MEK solutions, as well as NBR melts were also studied for relevant information. It is concluded that the hydrogenation kinetics deviates from that reported by Parent et al. [6] when polymer is in high concentration and/or catalyst is in low concentration; and that the reaction solution (HNBR/NBR-MCB solution) deviates from Newtonian behavior when polymer concentration and hydrogenation degree are high.

Ce travail, effectué dans le cadre d'une convention de recherche avec la Société ISOCHEM, a pour objectif la mise au point d'un nouveau procédé de synthèse de la pyrazolidine par la voie Raschig directe et par voie indirecte, en transitant par la 1 et 2-pyrazoline, suivie d'une hydrogénation catalytique. Cette hydrazine suscite un grand intérêt en raison de ses nombreuses applications dans l'industrie pharmaceutique et des cosmétiques. Cette thèse a été financée par le Centre National de Recherche Scientifique dans le cadre d'une bourse doctorale ingénieure/PED. La première partie est consacrée à l'étude du procédé Raschig direct qui résulte de l'action de l'hypochlorite de sodium sur un excès d'amine. La définition du process a nécessité la détermination des cinétiques et des mécanismes réactionnels afin de déterminer les rendements, les temps de séjour et de simuler numériquement l'ensemble des opérations de synthèse. Les conditions d'extraction ont été établies en exploitant les particularismes des équilibres entre phases impliqués afin d'élaborer le flow-sheet correspondant. La seconde partie est relative à la voie indirecte. Elle est basée sur l'élaboration de la 1- pyrazoline par une double déshydrohalogénation du N,N-dichloro-1,3 diaminopropane. La pyrazolidine est ensuite obtenue par hydrogénation catalytique du groupe azo. Un modèle global d'élaboration de la pyrazolidine a été établi qui nous a permis de déterminer les conditions optimales et de définir les segments synthèses et extractions ainsi que les différentes opérations unitaires du procédé ainsi que les bilans matière et énergie / This work, conducted as part of a research agreement with the Company ISOCHEM, aims to develop a new synthesis of pyrazolidine by the raschig method and by indirect way via 1 and 2-pyrazoline followed by catalytic hydrogenation. This hydrazine is very important, because of its many applications in the pharmaceutical and cosmetic industries. This thesis was funded by the National Center for Scientific Research as part of a doctoral fellowship engineer / PED. The first part is devoted to the study of the direct Raschig process resulting from the action of sodium hypochlorite in an excess of amine. The definition of the process involved the determination of the kinetic and reaction mechanisms to determine yields, residence time and to simulate numerically the overall operations of synthesis. The extraction conditions were established by exploiting the peculiarities of the phase equilibria in order to developed the flow-sheet. The second part relates to the indirect way. It is based on the synthesis of the 1 pyrazoline by double dehydrohalogenation of N,N-dichloro-1,3-diaminopropane. The pyrazolidine is then obtained by catalytic hydrogenation of the azo group. A global model for developing the pyrazolidine was established which allowed us to determine the optimum conditions and to identify segments syntheses and extractions as well as various unit operations of the process and the mass and energy balances

The main objective of the present thesis is to deepen the understanding of the mechanisms involved in catalytic growth of carbon nanotubes (CNT) and related processes, such as the catalytic hydrogenation, and to use this knowledge to optimize the experimental approaches in order to gain better control in the synthesis and modification of carbon nanomaterials. Controlled growth of the CNT is achieved using gas-phase prepared catalyst particles (Fe, Co) which serve as individual catalytic nucleation sites in a chemical vapor deposition (CVD) process. These studies highlight that the controlled preparation of catalyst particles is a crucial step in order to control the CNT morphology. The resultant CNT diameter and the CNT density are found to increase with increasing nanoparticle diameter and density, respectively. The number of walls of the CNT also increases with increasing primary catalyst size. The experimentally derived correlations between the particle diameter on one hand and the CNT diameter and the CNT number of walls on the other hand are attributed to an increase of the catalyst's volume-to-surface area ratio with increasing particle size. While the availability of carbon dissolved within the catalyst at the point of nucleation is determined by the catalyst volume, the amount of carbon required to form a cap depends on the surface area of the catalyst particle. Electron microscopy studies of the catalyst/substrate/carbon interfaces of CNT grown from Fe nanoparticles reveal that the CNT walls are anchored to the oxide substrate which contests the general argument that the CNT walls stem from atomic steps at the catalyst. It is argued that after nucleation, the substrate itself provides a catalytic functionality towards the stimulation of ongoing CNT growth, whereas the catalytic activity of the metal particle is more restricted to the nucleation process. Selective hard-magnetic functionalization of CNT tips has been achieved in a plasma-enhanced CVD process. Hard-magnetically terminated CNT, i.e. CNT with a FePt nanoparticle at each tip, are directly grown using FePt catalysts. Fe/Pt thin films with a strongly over-stoichiometric Fe content in the starting catalyst composition yield CNT with a significant number of particles in the hard-magnetic phase. Anisotropic etching of graphite through Co catalyst particles in hydrogen atmosphere at elevated temperatures (i.e. catalytic hydrogenation) is reported. Catalytic hydrogenation is a potential key engineering route for the fabrication of graphene nanoribbons with atomic precision. While in previous studies the etching of zigzag channels was preferred, the present investigations reveal preferential etching of armchair channels, which provides a means to tailor graphene nanostructures with specific edge termination. Further, detailed morphological and structural characterization of the Co particles provide insight into the hydrogenation mechanism which is still a matter of controversy.