Nos últimos anos, questões ambientais têm merecido destaque na mídia nacional e internacional. A química tem uma grande participação nos dias atuais com os inúmeros produtos fundamentais à humanidade. A sua presença pode ser destacada desde diversos combustíveis aos mais complexos medicamentos. As reações de síntese orgânica devem ser guiadas por novas práticas mais sustentáveis. Nesse campo, tem-se o conceito da Green Chemistry ou Química Verde, que consiste na estratégia em desenvolver metodologias e processos que usem e gerem a menor quantidade de materiais tóxicos e/ou inflamáveis ou reaproveitáveis. Com o intuito de contribuir com a Química Verde, estudou-se a síntese de iminas que consistiu da primeira etapa do processo de aminação livre de solventes orgânicos e apresentaram rendimentos superiores a 95,0 %; gem-dicloroaziridinas foram preparadas a partir de inserção de diclorocarbeno em iminas em condições mínimas de solvente orgânico, utilizando como catalisador o KF/Al2O3 e com rendimentos superiores a 98,0%. As gem-dicloroaziridinas foram convertidas em amidas por hidrolise, na ausência de solvente e com rendimentos superiores a 98,0%. Dentro do conceito de Química Verde foram preparadas as seis iminas: N-benzilfenilmetanoimina, N-fenil-furilmetanoimina, N-fenilfenilmetanoimina, N-fenil-(4-metoxifenil)-metanoimina, N-benzil-(4-metoxifenil)metanoimina e N-furfurilfurilmetanoimina; duas gem-dicloroaziridinas: 2,2-dicloro-1,3-difenilaziridina e 1-benzil-2,2-dicloro-3-fenilaziridina e duas amidas: cloro-fenilacetanilida e N-benzil-cloro-fenilacetamida. / For the last years Environmental issues have deserved featured in the National and International media. Chemistry has had great participation on currently days with countless products which are fundamental to humanity. Its presence can be detached from various fuels to the most complex drugs.The organic synthesis reactions should be guided by more sustainable new practices. In this field, the Green Chemistry concept or (Química Verde) strategy which aims to develop methodology and and/or processes which use and generate the minimum quality of toxic inflammable material. With the purpose of contribute to green chemistry, we studied the synthesis of imines which consisted of the first stage of the process of amination, free of organic solvents and have yields higher than 95%; gem-dichloroaziridine were prepared from the imines insertion dichlorocarbene in a minimum of organic solvent conditions, using as catalyst KF/Al2O3 and yields higher than 98%. The gem-dichloroaziridines were converted to amides by hydrolysis in absence of solvent and yields higher than 98.0%. Within the concept of Green Chemistry were prepared six imines: N-benzyl- phenylmethanimine, N-phenyl-2- furylmethanimine, N-phenyl- phenylmethanimine, N-phenyl-(4-methoxyphenyl)methanimine, N-benzyl-(4-methoxyphenyl)metha-nimine,N-(2-furylmethyl)-2-furylmethanimine; two gem-dichloroaziridinas: 2,2-dichloro-1,3-diphenyla-ziridine and 1-benzyl-2,2-dichloro-3-phenylaziridine and two amides: chlorophenylacetanilide and N-benzyl-chloro-phenylacetamide.

A química verde, que tem a preocupação com o desenvolvimento de tecnologias e processos incapazes de causar poluição, tem sido citada cada vez mais em destaque, pela mídia, como mais uma das iniciativas para prevenção da poluição desenfreada. Neste estudo tem-se buscado a redução ou eliminação de solventes, adaptação dos sistemas reacionais para operação em temperatura ambiente e aumento do rendimento em processos de reações guiados pelos doze princípios da química verde. O objetivo deste trabalho consiste na síntese de intermediários de princípios ativos para uso industrial, através de processos de formação de oximas e oximas éteres. O trabalho foi dividido em duas etapas principais, preparação de oximas e preparação de oximas éteres. Na primeira preparou-se oximas através da reação de aldeídos (benzaldeído, furfuraldeído, salicilaldeído e p-anisaldeído) e cetonas (ciclopentanona, ciclohexanona, metil etil cetona, benzofenona e acetofenona) com cloreto de hidroxilamina, sem a utilização de solventes orgânicos e sem adição de água. Na segunda o objetivo foi preparar oximas éteres (O-butil benzaldeído oxima, O-butil furfuraldeído oxima, N-butoxi-(2-butoxifenil) metanimina, O-butil p-anisaldeído oxima, O-butil ciclohexanona oxima, O-butil ciclopentanona oxima e O-butil metil etil cetona oxima) a partir da alquilação de oximas utilizando um suporte sólido de KF/Al2O3 como catalisador. Todos os compostos foram caracterizados por RMN 13C (apt) e alguns por infravermelho e RMN 1H. / Green chemistry, which is concerned with the development of technologies and processes incapable of causing pollution, has been cited increasingly highlighted, by the media, as another of the initiatives to prevent pollution rampant. This study has sought a reduction or elimination of solvents, reaction to adjust the systems operating at room temperature and yield increase in reactive processes that are guided by the twelve principles of green chemistry. The objective of this work is the synthesis of active intermediates for industrial use, through processes of formation of oximes, oximes ethers. The work was divided into two phases, preparation of oximes and preparation of oximes ethers. In the first was prepared oximes by reaction of aldehydes (benzaldehyde, furfuraldeyde, salicylaldehyde and p-anisaldeyde) and ketones (cyclopentanone, cyclohexanone, methyl ethyl ketone, benzophenone and acetophenone) with hydroxylamine chloride without the use of organic solvents and without adding water. For the second was prepared oximes ethers (O-butyl benzaldheyde oxime, O-butyl furfuraldeyde oxime, N-butoxy-(2-butoxyphenyl) methanimine, O-butyl p-anisaldeyde oxime, O-butyl cyclohexanone oxime, O-butyl cyclopentanone oxime e O-butyl methyl ethyl ketone oxime) from the alkylation of oximes, using a solid support as catalyst KF/Al2O3. All compounds were characterized by 13C NMR (apt) and some infrared and 1H NMR.

O apelo estético da odontologia moderna tem impulsionado a busca por materiais cerâmicos de alto desempenho estético e mecânico. Este trabalho objetivou o desenvolvimento de fibras cerâmicas de alumina/aluminato de gadolínio (Al2O3/GdAlO3) obtidas por meio de fusão a laser (laser heated pedestal growth LHPG) e a sua aplicação como reforço de materiais odontológicos. Os pedestais foram obtidos a partir da mistura dos pós precursores (óxido de gadolínio (Gd2O3) e óxido de alumínio (Al2O3) pré-sinterizados para a obtenção de fibras de Al2O3/GdAlO3 de 0,8 mm de diâmetro médio. Variou-se: a velocidade de puxamento das fibras de 48mm/h a 240mm/h, em pedestais de composição eutética; e em outro grupo a composição dos pedestais (da composição eutética (23 mol% de Gd2O3 e 77 mol% de Al2O3) a 5 % (em peso) de excesso de Al2O3), puxadas com velocidade fixa de 96 mm/h. A melhor condição de obtenção da fibra foi com a velocidade de puxamento de 240mm/h que forneceu fibras com 0,6m de espaçamento médio entre as fases e 1790 MPa de resistência à flexão. Quando as fibras foram aplicadas como reforço de porcelana odontológica houve um aumento da resistência à flexão de 91MPa para 218MPa. Por meio desta metodologia, observou-se que as fibras cerâmica de Al2O3/GdAlO3 apresentaram elevado desempenho mecânico e compatibilidade com porcelanas odontológicas que indicam uma grande potencialidade de uso como reforço estrutural de cerâmicas odontológicas. / The esthetic appeal of modern Dentistry has prompted the search for ceramic materials with high esthetic and mechanical performance. This research aimed at the development of Al2O3/GdAlO3 ceramic fibers, obtained by laser heated pedestal growth (LHPG) and its application as reinforcement of dental materials. Pedestals were obtained from the mixture of precursor powders (Gd2O3 e Al2O3), pre-sintered to form Al2O3/ GdAlO3 fibers with average diameter of 0,8 mm. Variables were: fiber pulling rates (in pedestals of eutectic composition): from 48 mm/h to 240 mm/h; and pedestal composition: from eutectic composition (23 mol% of Gd2O3 and 77 mol% of Al2O3) to 5 wt% of excess Al2O3, pulled at 96 mm/h. The best results were obtained with a pulling rate of 240 mm/h, which originated fibers with average distance between phases of 0.6 m and three-point bending flexural strength of 1790 MPa. When fibers were used as re-enforcement of dental porcelain (Cerabien- Noritake), an increase in flexural strength from 91 MPa to 218 MPa was obtained. The methods employed in this study allowed the observation that Al2O3/GdAlO3 ceramic fibers presented high mechanical performance and compatibility with dental porcelain, indicating a significant potential as re-enforcement of dental ceramics for infrastructure.

Hypereutectic Al-Si alloys are of increasing interest for applications that require a combination of light weight and high wear resistance, such as pistons, liner-less engine blocks and pumps. The wear resistance of this class of alloys is due to the presence of hard primary Si particles formed during casting. The objective of this work was to develop one or more methods of refining primary silicon in cast hypereutectic Al-Si alloys to compete with the conventional process of adding phosphorous and to achieve the simultaneous modification of silicon in the Al-Si eutectic. A robust sampling/casting technique was developed to minimise macro-segregation of primary silicon during solidification of hypereutectic Al-Si alloys by using water cooled steel mould with cooling rate in excess of 15 K/s. The morphology of silicon phases was found to change with increasing melt temperature and cooling rate. The high cooling rate and superheat temperature produces a good distribution of polyhedral primary silicon particles in a refined lamellar eutectic matrix in solidification of commercial purity Al-Si alloys. Removing Ca by fluxing with K2SiF6 prior to casting can improve the refinement and modification effect of Mg and Sb respectively. Effects of various inoculants were studied. Microstructural analysis showed that Mg and ZnS refined primary Si whereas MgO, CaO and Na2S coarsened the primary Si together with a modification effect on the eutectic Si. Adding Zn had no effect on morphology of Si phases. Refinement of both primary and eutectic silicon phases was observed for the Al-15Si alloy with Mg content ≤ 0.3 wt%. P-doped γ-Al2O3 was found to be a potent substrate to nucleate primary silicon whilst good modification of the eutectic matrix is retained during solidification of hypereutectic Al-Si alloys. On using P-doped γ-Al2O3 could be a perfect and clean source of P without additional impurities. A new solid-liquid duplex casting process was devised to achieve simultaneous refinement and modification of Si phases in hypereutectic Al-Si alloys with improvement in mechanical properties. The static mechanical properties of Al-Si produced by the solid-liquid duplex casting process are significantly better than conventionally cast untreated Al-Si and slightly better than conventionally cast Al-Si treated with P and/or Sr. A novel Al-ZnS master alloy was developed by in situ reaction of Zn and Na2S in the Al melt. The results from this study leave little doubt that this novel Al-ZnS master alloy is a promising refiner in solidification of hypereutectic Al-Si alloys. It refines primary silicon to the same extent as that achieved by adding P via Cu-P following the same refinement mechanism.

Different types of alumina containing coatings were made on lithiumand copper in the purpose to mechanically hinder the growth ofdendrites. Lithium, coated with polymer-alumina composites wereplaced in symmetric cells for in situ studies by a light microscope.The coatings did not block the dendrites, but they did change thegrowth rate and morphology of them, probably throw both chemicalinteractions and changes in ion transportation. Also the stability ofcapacity were tested for the same coatings, the result showed abigger capacity drop for cells containing coated lithium versus cellswithout coatings.Attempted alumina coatings were also made by a solgel technique, bydirect reaction with the compound trimethylaluminium and with analumina containing acetonitrile solution.The theses also includes a study of the stability of lithium inadiponitrile. A higher amount of LiTFSI salt in adiponitrile could bythis study be reported to inhibit the dissolution of lithium that wasseen for lower salt concentrations. The dissolution appeared when thesolution was used as an electrolyte in a symmetric lithium cell. Somedifferences could be seen when the lithium surface were studied byXPS after interaction with high, low and zero concentration LiTFSI.Both the XPS studies and the absences of lithium dissolutionindicates that a more or less stable SEI had been formed.

Nos últimos anos surgiu um tipo de bateria que tem gerado grande interesse para emprego em bancos de armazenamento estacionário. Tal tecnologia baseia-se na utilização de um eletrólito sólido β/β\'\'-Al2O3 que permite o transporte de íons de sódio entre um eletrodo positivo e um negativo. O eletrólito sólido β/β\'\'-Al2O3 apresenta uma estrutura cristalina diferenciada que permite grande mobilidade dos íons de sódio. O presente trabalho tem como objetivo principal obter eletrólito sólido β/β\'\'-Al2O3, utilizando pós preparados pelo processo mistura de óxidos e avaliar o desempenho elétrico dos eletrólitos com a deposição de filmes do mesmo substrato variando a concentração de sólidos presentes e correlacionar sua condutividade elétrica com sua porosidade. As amostras de β/β\'\'-Al2O3 foram sintetizadas, ocorrendo a formação da fase pretendida em temperaturas superiores a 1100°C. Os teores relativos das fases β/β\'\'-Al2O3 mostrou-se dependente da temperatura. Pós calcinados em temperaturas mais elevadas sofrem volatilização do sódio, sendo o teor máximo obtido da fase β\'\' durante o processo foi de 64%. Amostras sinterizadas em dois estágios, a 1600°C por 20 minutos seguida de tratamento térmico a 1475°C por 2 horas, apresentaram densificação maior em relação à amostras sinterizadas em um estágio. Sua microestrutura sofreu crescimento de grãos formando uma microestrutura duplex com grãos na forma de placas alongadas distribuídas em uma matriz de grãos finos. A partir da caracterização de suspensões aquosas de β/β\'\'-Al2O3 evidenciou a alteração do comportamento reológico exibido por suspensões dos pós cerâmicos em função da concentração em volume de sólidos de seu substrato em: 15%, 20%, 30% e 40%, e então os eletrólitos foram conformados por spin-coating. A técnica de espectroscopia de impedância foi importante na identificação das fases presentes na cerâmica β/β\'\'-Al2O3 e no mecanismo de condução elétrica, ocorrendo condução no volume (grãos), havendo uma condução maior na fase β-alumina. / In recent years has emerged a type of battery that has generated great interest for employment in stationary storage banks. Such technology is based on the use of a solid electrolyte β/β\'\'-Al2O3 that allows the transport of sodium ions between a positive and negative electrode. The solid electrolyte β/β\'\'-Al2O3 presents a differentiated crystalline structure that allows great mobility of the sodium ions. The main objective of this work is to obtain solid electrolyte β/β\'\'-Al2O3, using powders prepared by the process of mixing oxides and to evaluate the electric performance of the electrolytes with the deposition of films of the same substrate varying the concentration of solids present and to correlate their Conductivity with its porosity. The samples of β/β\'\'-Al2O3 were synthesized, with the formation of the desired phase occurring at temperatures above 1100°C. The relative levels of the β/β\'\'-Al2O3 phases were temperature dependent. Post calcined at higher temperatures undergoes sodium volatilization, the maximum obtained content of the phase during the process was 64%. Two-stage sintered samples at 1600°C for 20 minutes followed by heat treatment at 1475°C for 2 hours showed higher densification than sintered samples at one stage. Its microstructure underwent grain growth forming a duplex microstructure with grains in the form of elongated plates distributed in a fine grained matrix. From the formulation of aqueous suspensions of β/β\'\'-Al2O3 showed the alteration of the rheological behavior exhibited by suspensions of the ceramic powders as a function of the volume concentration of their substrate solids in: 15%, 20%, 30% and 40%, And then the electrolytes were formed by spin-coating. The impedance spectroscopy technique was important in the identification of the phases present in the ceramic β/β\'\'-Al2O3 and in the electrical conduction mechanism, occurring conduction in the volume (grains), with a higher conduction in the β-alumina phase.

Visando a produção de hidrogênio, como uma fonte renovável de energia, estudaram-se as reações de reforma a vapor e oxidativa do etanol sobre catalisadores de Ru/CeO2-Al2O3. Foi verificado o efeito do suporte e das interações metal/suporte sobre a atividade e seletividade para as reações. Os suportes e catalisadores foram caracterizados por fisissorção de nitrogênio pelo método B.E.T., para avaliar as áreas superficiais específicas, espectroscopia dispersiva de raios-X (EDX), para determinar a distribuição qualitativa da fase metálica sobre os suportes, difração de raios-X (DRX), para identificação das fases óxidas, espectroscopia na região do ultra-violeta e do visível (UV-vis NIR), para avaliar as transições eletrônicas presentes no material, e redução a temperatura programada (RTP), para avaliação do comportamento de redução e das fases redutíveis. Através dos ensaios catalíticos, pode-se verificar que todos os catalisadores foram ativos para ambas as reações de reforma, sob as temperaturas de 400, 600 e 700ºC, onde a conversão do etanol aumentou com o aumento da temperatura e com o aumento da adição de CeO2 ao suporte catalítico. O catalisador 3%Ru/CeO2 foi o mais ativo frente a reação de reforma a vapor e o 3%Ru/25%CeO2-Al2O3 o catalisador mais ativo para a reação de reforma oxidativa do etanol. A maior seletividade para H2 foi obtida a 600ºC para ambas as reações de reforma, com exceção dos catalisadores 3%Ru/20%CeO2-Al2O3, que foi mais seletivo a 700ºC para a reforma a vapor, e 3%Ru/CeO2, que foi mais seletivo a 400ºC para a reforma oxidativa. / Aiming at hydrogen production, as a source of renewable energy, Ru/CeO2-Al2O3 catalysts were studied in ethanol steam reform and ethanol oxidative reforming. The effect of the support and metal/support interaction was verified on the activity and selectivity of the reactions. The supports and catalysts were characterized by x-rays dispersive spectroscopy (XDS), to verify the qualitative distribution of the metallic phase on the supports, x-rays diffraction (XRD), for identification of the crystalline oxide phases, spectroscopy in the region of the ultraviolet and the visible (UV-vis NIR), to evaluate the electronic transitions present in the material, and temperature programmed reduction (TPR), for evaluation of the reductive phases. According to the catalytic tests, all catalysts were active for both reactions under the temperatures of 400, 600 and 700ºC, where the ethanol conversion increased together with the increase of the temperature and, with the addition of CeO2 to the catalytic support. The 3%Ru/CeO2 catalyst was the most active for ethanol steam reforming and the 3%Ru/25%CeO2-Al2O3 catalyst was the most active for ethanol oxidative reforming. The higher selectivity for H2 occurred at 600ºC for both reactions, excluding the 3%Ru/20%CeO2-Al2O3 catalyst, which was more selective at 700ºC for steam reforming, and the 3%Ru/CeO2 catalyst, which was more selective for the oxidative reforming at 400ºC.

Impulsionados pela busca de fontes limpas de energia, surgem os processos de combustao com recirculacao quimica (CLC), e reforma com recirculacao quimica (CLR). CLC e CLR sao processos quimicos para oxidacao de hidrocarbonetos gasosos. E utilizada a acao de transportadores de oxigenio (TO), para transferir oxigenio do ar para o combustivel (neste caso o metano), evitando-se o contato direto entre ar atmosferico e metano por diversos motivos. Os TOs, compostos por oxidos metalicos na forma de po fino, circulam continuamente entre dois reatores de leito fluidizado (reator de ar e de combustivel), sofrendo sucessivos ciclos de reducao e oxidacao. Os processos se diferenciam com relacao aos produtos, em CLC objetiva-se a geracao de energia, atraves da oxidacao completa do combustivel, resultando em uma mistura de CO2 e H2O, podendo ser facilmente separada por condensacao. No caso do CLR a oxidacao ocorre de maneira parcial, dando origem a uma mistura de gas de sintese (H2 + CO). O CLC apresenta vantagens com relacao aos processos tradicionais de captura de CO2, pois nao se faz necessaria a utilizacao de processos secundarios para separacao gasosa, economizando assim energia, alem do fato de nao gerar gases do tipo NOx. O presente trabalho apresenta a preparacao de duas series de materiais, via impregnacao seca, uma com composicao 2, 4 e 8% m/m de oxido de niquel e outra com os mesmo teores de oxido de niobio, suportados sobre alumina comercial de alta area superficial especifica. Os materiais foram caracterizados pelas tecnicas de picnometria a helio, volumetria de nitrogenio, porosimetria por intrusao de mercurio, DRX, MEV, TPR 5%H2/N2 analisado com TCD em ChemBet, TPR 5%CH4/Ar e TPO 5%O2/Ar sendo a variacao de massa analisada em termobalanca (TGA/DSC), alem de se utilizar de espectrometria de massas para analise dos gases gerados. Os diferentes transportadores de oxigenio foram testados em reator de leito fixo, sendo avaliados em diferentes condicoes experimentais tais como: temperaturas de operacao, vazoes de reagentes gasosos, concentracoes de metano, adicao de CO2 e H2O ao combustivel. Os produtos da reacao no reator de leito fixo foram analisados por cromatografia gasosa e espectrometria de massa. Os resultados mostraram que; o deposito de carbono sobre o catalisador pode ser drasticamente reduzido com a adicao de mistura oxidante junto ao combustivel e que estes oxidos estudados tem potencial aplicacao industrial, mostrando-se seletivos para reforma do metano com consecutiva producao de gas de sintese. / Driven by the demand for clean energy sources, arise chemical-looping combustion - CLC, and chemical-looping reforming - CLR. CLC and CLR are chemical processes for oxidation of gaseous hydrocarbons. Both of them use the action of catalysts, here called oxygen carriers (OC), which transfers oxygen from the air to the fuel (in this case methane), avoiding the direct contact between the two gases for various reasons. The OC\'s are composed of metal oxides in the form of fine power, circle continuously between two fluidized bed reactors (fuel reactor and air reactor), suffering successive cycles of reduction and oxidation. The two processes differ in relation to the products; the aim of CLC is generation of energy (heat), through the complete oxidation of the fuel, resulting in a mixture of CO2 and H2O, which can be easily separated by condensation. In the case of CLR, the oxidation occurs partially, resulting in synthesis gas, a mixture of H2 and CO. The CLC processes shows advantages when compared to other traditional processes for capture of CO2, because it is not necessary to use secondary processes for gas separation, saving energy, besides the fact of no NOx is generated. This work describes the preparation of two series of materials via dry impregnation, which are composed of 2, 4 and 8% w/w niobium oxide or nickel oxide, supported on commercial alumina, with high specific surface area. The materials were characterized by the techniques of helium pycnometry, nitrogen volumetry, mercury intrusion porosimetry, DRX, MEV, TPR 5% H2/N2 analyzed with TCD in ChemBet, TPR 5% CH4/Ar and TPO 5% O2/Ar, being the changes in mass and heat analyzed in a thermogravimetric balance (TGA/DSC) coupled to a mass spectrometer permitting the analysis of the generated gases. The different oxygen carriers were tested in a fixed bed reactor, evaluated in different experimental conditions, such as operation temperature, flow rate of gaseous reactants, methane concentrations, addition of CO2 and H2O to the fuel. The products of the reaction in the fixed bed reactor were analyzed by gas chromatography and mass spectrometry. The results show that: the carbon deposits over the catalysts can be drastically reduced by addition of oxidizing mixture together to the fuel and these studied oxides have a potential industrial application, showing selectivity to reforming of methane with consecutive synthesis gas production.

Impulsionados pela busca de fontes limpas de energia, surgem os processos de combustao com recirculacao quimica (CLC), e reforma com recirculacao quimica (CLR). CLC e CLR sao processos quimicos para oxidacao de hidrocarbonetos gasosos. E utilizada a acao de transportadores de oxigenio (TO), para transferir oxigenio do ar para o combustivel (neste caso o metano), evitando-se o contato direto entre ar atmosferico e metano por diversos motivos. Os TOs, compostos por oxidos metalicos na forma de po fino, circulam continuamente entre dois reatores de leito fluidizado (reator de ar e de combustivel), sofrendo sucessivos ciclos de reducao e oxidacao. Os processos se diferenciam com relacao aos produtos, em CLC objetiva-se a geracao de energia, atraves da oxidacao completa do combustivel, resultando em uma mistura de CO2 e H2O, podendo ser facilmente separada por condensacao. No caso do CLR a oxidacao ocorre de maneira parcial, dando origem a uma mistura de gas de sintese (H2 + CO). O CLC apresenta vantagens com relacao aos processos tradicionais de captura de CO2, pois nao se faz necessaria a utilizacao de processos secundarios para separacao gasosa, economizando assim energia, alem do fato de nao gerar gases do tipo NOx. O presente trabalho apresenta a preparacao de duas series de materiais, via impregnacao seca, uma com composicao 2, 4 e 8% m/m de oxido de niquel e outra com os mesmo teores de oxido de niobio, suportados sobre alumina comercial de alta area superficial especifica. Os materiais foram caracterizados pelas tecnicas de picnometria a helio, volumetria de nitrogenio, porosimetria por intrusao de mercurio, DRX, MEV, TPR 5%H2/N2 analisado com TCD em ChemBet, TPR 5%CH4/Ar e TPO 5%O2/Ar sendo a variacao de massa analisada em termobalanca (TGA/DSC), alem de se utilizar de espectrometria de massas para analise dos gases gerados. Os diferentes transportadores de oxigenio foram testados em reator de leito fixo, sendo avaliados em diferentes condicoes experimentais tais como: temperaturas de operacao, vazoes de reagentes gasosos, concentracoes de metano, adicao de CO2 e H2O ao combustivel. Os produtos da reacao no reator de leito fixo foram analisados por cromatografia gasosa e espectrometria de massa. Os resultados mostraram que; o deposito de carbono sobre o catalisador pode ser drasticamente reduzido com a adicao de mistura oxidante junto ao combustivel e que estes oxidos estudados tem potencial aplicacao industrial, mostrando-se seletivos para reforma do metano com consecutiva producao de gas de sintese. / Driven by the demand for clean energy sources, arise chemical-looping combustion - CLC, and chemical-looping reforming - CLR. CLC and CLR are chemical processes for oxidation of gaseous hydrocarbons. Both of them use the action of catalysts, here called oxygen carriers (OC), which transfers oxygen from the air to the fuel (in this case methane), avoiding the direct contact between the two gases for various reasons. The OC\'s are composed of metal oxides in the form of fine power, circle continuously between two fluidized bed reactors (fuel reactor and air reactor), suffering successive cycles of reduction and oxidation. The two processes differ in relation to the products; the aim of CLC is generation of energy (heat), through the complete oxidation of the fuel, resulting in a mixture of CO2 and H2O, which can be easily separated by condensation. In the case of CLR, the oxidation occurs partially, resulting in synthesis gas, a mixture of H2 and CO. The CLC processes shows advantages when compared to other traditional processes for capture of CO2, because it is not necessary to use secondary processes for gas separation, saving energy, besides the fact of no NOx is generated. This work describes the preparation of two series of materials via dry impregnation, which are composed of 2, 4 and 8% w/w niobium oxide or nickel oxide, supported on commercial alumina, with high specific surface area. The materials were characterized by the techniques of helium pycnometry, nitrogen volumetry, mercury intrusion porosimetry, DRX, MEV, TPR 5% H2/N2 analyzed with TCD in ChemBet, TPR 5% CH4/Ar and TPO 5% O2/Ar, being the changes in mass and heat analyzed in a thermogravimetric balance (TGA/DSC) coupled to a mass spectrometer permitting the analysis of the generated gases. The different oxygen carriers were tested in a fixed bed reactor, evaluated in different experimental conditions, such as operation temperature, flow rate of gaseous reactants, methane concentrations, addition of CO2 and H2O to the fuel. The products of the reaction in the fixed bed reactor were analyzed by gas chromatography and mass spectrometry. The results show that: the carbon deposits over the catalysts can be drastically reduced by addition of oxidizing mixture together to the fuel and these studied oxides have a potential industrial application, showing selectivity to reforming of methane with consecutive synthesis gas production.

γ-Al2O3 supported Co-W based catalysts with varying Co (1 - 3 wt %) and W (7 - 13 wt %) loadings were prepared using impregnation and sonochemical methods. All prepared catalysts were characterized with elemental analysis, BET analysis, X-ray diffraction (XRD), NH3 temperature programmed desorption (TPD), temperature programmed reduction (TPR) and thermogravimetry analysis (TGA). <p>The performances of all the synthesized catalysts were tested at a pressure of 8.9 MPa, LHSV of 2 h-1 and temperatures of 340, 350 and 360 °C in a laboratory trickle bed microreactor for hydrodesulphurization (HDS) and hydrodenitrogenation (HDN) of light gas oil (LGO) derived from Athabasca bitumen. The performance tests with impregnated catalysts indicated a maximum in activity for HDS and HDN reactions (sulfur and nitrogen conversions at 93.0 and 57.1 % at 360 °C) for Co(3 wt %)-W(10 wt %)/γ-Al2O3 whereas the performance tests with sonochemically prepared catalysts showed a maximum in activity (sulfur and nitrogen conversions at 87.9 and 42.5 % at 360 °C) for Co(3 wt %)-W(11.5 wt %)/ γ-Al2O3. These two catalysts were selected for detail performance, optimization and kinetic studies. The effects of reaction temperature (340 - 380 °C), pressure (7.6 - 10.3 MPa), liquid hourly space velocity (1.5 - 2.0 h-1) and hydrogen gas/gas oil ratio (400 - 800 mL/mL) were examined on HDS and HDN of LGO with these catalysts. The reaction kinetics for HDS was best fitted with a Power Law model whereas same for HDN was found to be best represented by a Langmuir-Hinshelwood model with a reasonable accuracy (0.90 <R2 <0.95). The activation energy for HDS of LGO were 14 and 12 kJ/mol for selected impregnated and sonochemically prepared catalysts whereas the same for HDN were 9 and 14 kJ/mol for these catalysts, respectively. Calculation showed that the fitted HDS rate expressions were apparent and HDN rate expressions were intrinsic under existing reaction conditions. It also showed that the pore diffusion resistances for both HDS and HDN increased with an increase in reaction temperature from 340 to 380 °C.