Discovery of mesoporous materials by Mobil researchers in 1992 opened a new field in catalytic applications. The materials designated as M41S family are MCM-41 with one-dimensional hexagonal structure, MCM-48 with three-dimensional cubic structure and MCM-51 with unstable lamellar structure. This family of materials have high surface areas up to 1500 m2/g, narrow pore size distributions with pore sizes varying from 20 to 100 &Aring / . These materials can be activated by incorporation of metals or active compounds into their structures. In this study, copper and nickel incorporated MCM-41 type catalytic materials were synthesized via different methods namely, impregnation, high temperature and low temperature direct synthesis methods. The Cu-MCM-41, and Ni-MCM-41, as well as synthesized MCM-41 were characterized by using XRD, TEM, N2 sorption, SEM, XRF, EDS, AAS and TPR. MCM-41 was synthesized with high temperature direct synthesis method. High surface area values up to 1400 m2/g of MCM-41 mesoporous materials were obtained with high pore volumes up to 1.17 cc/g. Cu-MCM-41 type catalytic materials were synthesized with three different methods. Impregnation and high temperature direct synthesis methods gave better results than those of low temperature direct synthesis method. In impregnation, relatively high surface area values (730 m2/g) were obtained with Cu/Si mole ratio as high as 0.3 in the product. For the case of high temperature direct synthesis products, Cu/Si mole ratios as high as 0.26 were obtained with somewhat smaller surface areas (400 m2/g). Low temperature direct synthesis method is the least favorable method in metal loading. Ni-MCM-41 type of catalytic materials were synthesized by impregnation and high temperature direct syntheses methods. Ni incorporation by high temperature direct synthesis method gave high surface area values (560-930 m2/g) having Ni/Si mole ratios of 0.12-0.28.

Palladium based catalysts are widely used for C-C bonding reactions. This work describes the preparation of several such catalysts deposited onto siliceous, SBA-15 type support and common silica gel, whose surface was modified by organic chains with amine donor groups. The prepared catalysts have been tested in coupling reactions of organotin compounds and organic halides (Stille reactions) under various conditions.

Made available in DSpace on 2014-12-17T15:42:29Z (GMT). No. of bitstreams: 1 MarcelaNB_TESE.pdf: 4650032 bytes, checksum: 4b8ec547749f785718e5f099093fa925 (MD5) Previous issue date: 2013-09-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Intensive use of machinery and engines burning fuel dumps into the atmosphere huge amounts of carbon dioxide (CO2), causing the intensification of the greenhouse effect. Climate changes that are occurring in the world are directly related to emissions of greenhouse gases, mainly CO2, gases, mainly due to the excessive use of fossil fuels. The search for new technologies to minimize the environmental impacts of this phenomenon has been investigated. Sequestration of CO2 is one of the alternatives that can help minimize greenhouse gas emissions. The CO2 can be captured by the post-combustion technology, by adsorption using adsorbents selective for this purpose. With this objective, were synthesized by hydrothermal method at 100 ?C, the type mesoporous materials MCM - 41 and SBA-15. After the synthesis, the materials were submitted to a calcination step and subsequently functionalized with different amines (APTES, MEA, DEA and PEI) through reflux method. The samples functionalized with amines were tested for adsorption of CO2 in order to evaluate their adsorption capacities as well, were subjected to various analyzes of characterization in order to assess the efficiency of the method used for functionalization with amines. The physic-chemical techniques were used: X- ray diffraction (XRD), nitrogen adsorption and desorption (BET/BJH), scanning electron microscopy (SEM), transmission electron microscopy (TEM), CNH Analysis, Thermogravimetry (TG/DTG) and photoelectron spectroscopy X-ray (XPS). The CO2 adsorption experiments were carried out under the following conditions: 100 mg of adsorbent, at 25 ?C under a flow of 100 ml/min of CO2, atmospheric pressure and the adsorption variation in time 10-210 min. The X-ray diffraction with the transmission electron micrographs for the samples synthesized and functionalized, MCM-41 and SBA-15 showed characteristic peaks of hexagonal mesoporous structure formation, showing the structure thereof was obtained. The method used was efficient reflux according to XPS and elemental analysis, which showed the presence of amines in the starting materials. The functionalized SBA -15 samples were those that had potential as best adsorbent for CO2 capture when compared with samples of MCM-41, obtaining the maximum adsorption capacity for SBA-15-P sample / A intensa utiliza??o de m?quinas e motores queimando combust?veis despeja na atmosfera imensas quantidades de di?xido de carbono (CO2), causando a intensifica??o do Efeito Estufa. As mudan?as clim?ticas que v?m ocorrendo no mundo est?o diretamente relacionadas ?s emiss?es de gases de efeito estufa, principalmente CO2, devido, sobretudo, ao uso excessivo de combust?veis f?sseis. A busca por novas tecnologias para minimizar os impactos ambientais decorrentes deste fen?meno vem sendo investigadas. O sequestro de CO2 ? uma das alternativas que pode ajudar a minimizar as emiss?es desses gases. O CO2 pode ser capturado pela tecnologia p?s-combust?o, atrav?s do processo de adsor??o, utilizando adsorventes seletivos para este fim. Com este objetivo, foram sintetizados, pelo m?todo hidrot?rmico a 100?C, materiais mesoporosos do tipo MCM-41 e SBA-15. Ap?s as s?nteses os materiais foram submetidos ? etapa de calcina??o e, posteriormente, funcionalizados com diferentes tipos de aminas (APTES, MEA, DEA e PEI), atrav?s do m?todo de refluxo. As amostras funcionalizadas com as aminas foram testadas nos ensaios de adsor??o de CO2 afim de avaliar suas capacidades de adsor??o, bem como, foram submetidas a diversas an?lises de caracteriza??o no intuito de avaliar a efici?ncia do m?todo utilizado para a funcionaliza??o com as aminas. As t?cnicas f?sico-qu?micas utilizadas foram: Difra??o de Raios-X (DRX), Adsor??o e Dessor??o de nitrog?nio (BET/BJH), Microscopia eletr?nica de varredura (MEV), Microscopia eletr?nica de transmiss?o (MET), An?lise elementar CNH, Termogravimetria (TG/DTG) e Espectroscopia fotoeletr?nica de Raios-X (XPS). Os ensaios de adsor??o de CO2 foram realizados nas seguintes condi??es: 100 mg de adsorvente, temperatura de 25 ?C sob fluxo de 100 mL/min de CO2, press?o atmosf?rica e com varia??o no tempo de adsor??o de 10 a 210 min. Os difratogramas de Raios-X juntamente com as micrografias eletr?nicas de transmiss?o para as amostras sintetizadas e funcionalizadas, MCM-41 e SBA-15, apresentaram os picos caracter?sticos da forma??o de estrutura mesoporosa hexagonal, evidenciando que a estrutura do mesmo foi obtida. O m?todo de refluxo utilizado foi eficiente segundo as an?lises de elementar e XPS, na qual, mostrou a presen?a das aminas nos materiais de partida. As amostras funcionalizadas de SBA-15 foram as que tiveram melhor potencial como adsorvente para captura de CO2 quando comparadas com as amostras de MCM-41, obtendo a m?xima capacidade de adsor??o para a amostra SBA-15-P

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-30T16:37:00Z No. of bitstreams: 1 CLÁUDIA DOURADO MEDEIROS - DISSERTAÇÃO PPGEQ 2014..pdf: 1542895 bytes, checksum: 5a74f0ba9e6514c2859c363f528e0b6f (MD5) / Made available in DSpace on 2018-04-30T16:37:00Z (GMT). No. of bitstreams: 1 CLÁUDIA DOURADO MEDEIROS - DISSERTAÇÃO PPGEQ 2014..pdf: 1542895 bytes, checksum: 5a74f0ba9e6514c2859c363f528e0b6f (MD5) Previous issue date: 2014-04-02 / Capes / As peneiras moleculares mesoporosas possuem um arranjo hexagonal de mesoporos com diâmetros de poros que variam de 2 a 10 nm, possuindo assim uma área superficial elevada. A adição de um metal a sua estrutura tem como função gerar a acidez ao material o tornando mais reativo, aumentado assim a possibilidade do seu uso como catalisador na indústria do petróleo. Atualmente, um dos problemas encontrados pelos pesquisadores para obtenção desse tipo de peneira, é o longo tempo de formação das estruturas. No presente trabalho as peneiras moleculares mesoporosas MCM-41 e Al-MCM-41 foram sintetizadas utilizando dois processos hidrotermais, a tradicional e por micro-ondas, com o objetivo principal de reduzir o tempo de síntese do material. A peneira molecular MCM-41 foi sintetizada utilizando o processo hidrotermal tradicional, 100 oC por 48 horas , como também utilizando o processo hidrotermal de micro-ondas através de três metodologias, adotando diferentes tempos e temperaturas. Tomando como base os resultados obtidos com as sínteses da peneira molecular MCM-41 por meio do método hidrotermal de micro-ondas, os mesmos métodos foram aplicados para a peneira molecular Al-MCM-41 nas mesmas condições de tempo e temperatura. Através dos difratogramas foi possível perceber que a estrutura hexagonal foi formada. Verificouse que o melhor tempo de síntese da Al-MCM-41 se deu com 60 minutos a 130 oC. A partir destes dados, foram realizadas novas sínteses, reduzindo o tempo gradativamente. Os resultados das análises de DRX, MEV e FTIR comprovam que as peneiras moleculares mesoporosas foram formadas, sendo possível identificar sua estrutura e morfologia. Os melhores resultados de síntese para as peneiras moleculares mesoporosas MCM-41 e Al-MCM-41, foram nos tempos 60 e 40 minutos e temperatura de 130 oC, respectivamente. / The mesoporous molecular sieves have a hexagonal arrangement of mesopores with pore diameters ranging from 2 to 10 nm, which implies in a high surface area. The addition of a metal into these structures has the function of generating acidity in the material making it more reactive, increasing the possibility of using it as a catalyst into the oil industry. Nowadays, one of the problems found by researches to obtain these type of molecular sieves is the long time of structure formation taken by these materials. In this study, the mesoporous molecular sieves MCM - 41 and Al -MCM -41 were synthesized using two traditional microwave, with the primary goal of reducing the time of synthesis of the material hydrothermal processes. The molecular sieve MCM -41 was synthesized using the traditional hydrothermal process 100 °C for 48 hours , as well as hydrothermal process using microwave by three methods , adopting different times and temperatures . Based on the results obtained with the synthesis of molecular sieve MCM -41 by hydrothermal microwave method, the same methods were applied to the molecular sieve Al -MCM -41 under the same conditions of time and temperature. Through the DRX patterns was observed that the hexagonal structure was formed. It was found that the best time of synthesis of Al- MCM-41 was given 60 minutes at 130 oC. From these data, new syntheses were carried out by reducing the time gradually. The results of DRX, MEV and FTIR show that the mesoporous molecular sieves were formed, it is possible to identify their structure and morphology. The best results for the synthesis of mesoporous molecular sieves MCM - 41 and Al -MCM -41, were at times 60 and 40 minutes and temperatures of 130 °C, respectively.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The significant increase of carbon dioxide emissions in the atmosphere comes intensifying the global warming. The search for energetic source that turn emission down is of great importance, as well as the use of complementary actions like dioxide carbon capture process of the main emissions sources. From among some processes already very well-known industrially highlights chemical absorption with alkanolamine, which shows some disadvantages in being costly and generate waste derived from recovery. The use gas-solid selective in carbon dioxide adsorption has very advantages over absorption liquid amine such as easy handling without risks to the environment and recovering of adsorbent material, being possible to use industries plants with continuous flux. In this context were synthesized through hydrothermal method two materials of family M41S of type MCM-41 and MCM-48. Then the materials were impregnated with ethylenediamine by wet impregnation method. These materials were used for the carbon dioxide adsorption process and were characterized by several physic-chemical techniques. The powder X-ray diffraction patterns of the samples showed all peaks characteristics of MCM-41 and MCM-48 before and after impregnation with amines. The absorption spectrum in the infrared region showed bands due to Si-O and O-Si-O bonds in all materials and N-H bonds due to presence of amine in the supports after impregnation process. The thermogravimetric curves showed that stability of material containing amines is up to 100 °C. The materials showed N2 adsorption isotherms type IV, some with hysteresis type H1 and high surfaces areas (over 1000 m2 g-1). Carbon dioxide capture tests in flux system and atmosphere pressure showed significant drawbacks in the capture capacities of carbon dioxide for the materials impregnated with ethylenediamine in comparison to the values obtained with the MCM-41 and MCM-48 supports alone. Tests with closed system and pressure variation in the range of 0.5 to 30 bar allowed the construction of the isotherms to prepared materials of which were fitted using the Langmuir model. The results showed that the samples of MCM-41 and MCM-48 without impregnation are favorable for applications where high pressures are required. / O aumento significativo das emissões de dióxido de carbono na atmosfera vem acentuando o efeito do aquecimento global. A busca por fontes energéticas que minimizem as emissões é de grande importância, como também o uso de ações complementares como processos para captura deste gás das principais fontes emissoras. Dentre alguns processos já bem conhecidos industrialmente, destaca-se a absorção química com alcanolaminas, a qual apresenta algumas desvantagens por ser dispendiosa e gerar rejeitos da sua recuperação. O uso da adsorção gás-sólido seletiva de dióxido de carbono tem muitas vantagens sobre a absorção com aminas líquidas, tais como: fácil manipulação sem riscos ao ambiente, e recuperação do material adsorvente, podendo-se utilizar plantas industriais com fluxo contínuo. Neste contexto, foram sintetizados através do método hidrotérmico dois materiais da família M41S do tipo MCM-41 e MCM-48. Em seguida os materiais foram impregnados com etilenodiamina, através do método de impregnação por via úmida. Estes materiais foram utilizados para o processo de adsorção de dióxido de carbono e foram caracterizados por diversas técnicas físico-químicas. Os difratogramas de raios-X das amostras sintetizadas apresentaram os picos característicos do MCM-41 e do MCM-48 antes e após a impregnação com aminas. Os espectros de absorção na região do infravermelho mostraram bandas devido às ligações Si-O e O-Si-O em todos os materiais e de ligações N-H devido à presença da amina nos suportes após a impregnação. As curvas termogravimétricas mostraram que a estabilidade do material contendo aminas é de até 100 °C. Todos os materiais apresentaram isotermas de adsorção de N2 do tipo IV, alguns com histerese do tipo H1 e elevadas áreas superficiais (acima de 1000 m2 g-1). Os testes de captura de dióxido de carbono em sistema com fluxo e pressão atmosférica mostraram significativas reduções nas capacidades de captura para os materiais impregnados em comparação com os valores obtidos com os suportes MCM-41 e MCM-48. Testes com sistema fechado e variação de pressão na faixa de 0,5-30 bar permitiram o levantamento de isotermas de equilíbrio para os materiais preparados as quais foram ajustadas através do modelo de Langmuir. Os resultados mostraram que as amostras de MCM-41 e MCM-48 são favoráveis para aplicações onde altas pressões são requeridas.

No description available.

Made available in DSpace on 2014-12-17T15:41:45Z (GMT). No. of bitstreams: 1 MariaJFCpdf.pdf: 4931245 bytes, checksum: 45a7ea893d17f478c73adf56787579aa (MD5) Previous issue date: 2008-12-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The present work reports the study of nanoporous structures, aiming at their use in research directed to the current demand of the petroleum industry to value heavy oil. Initially, two ways were chosen for the synthesis of porous structures from the molecular sieves of type Si-MCM-41. In the first way, the structure MCM-41 is precursory for heteroatom substitutes of silicon, generating catalyst of the type Al-MCM-41 from two different methods of incorporation of the metal. This variation of the incorporation method of Aluminum in the structure of Si-MCM-41 was carried out through the conventional procedure, where the aluminum source was incorporated to the gel of synthesis, and the procedure post-synthesis, where the Aluminum source was incorporated in catalyst after the synthesis of Si-MCM-41. In the second way, the MCM-41 acts as a support for growth of nanocrystals of zeolite embedded in their mesoporous, resulting in hybrid MCM-41/ZSM-5 catalyst. A comparative analysis was carried through characterizations by XRD, FTIR, measures of acidity through n-butylamine adsorption for TGA, SEM-XRF and N2 adsorption. Also crystalline aluminosilicate with zeolitic structure MFI of type ZSM-5 was synthesized without using organic templates. Methodologies to the preparation of these materials are related by literature using conventionally reactants that supply oxides of necessary silicon and aluminum, as well as a template agent, and in some cases co-template. The search for new routes of preparation for the ZSM-5 aimed at, above all, the optimization of the same as for the time and the temperature of synthesis, and mainly the elimination of the use of organic templates, that are material of high cost and generally very toxic. The current study is based on the use of the H2O and Na+ cations playing the role of structural template and charge compensation in the structure. Characterizations by XRD, FTIR, SEM-XRF and N2 adsorption were also conducted for this material in order to compare the samples of ZSM-5 synthesized in the absence of template and those used industrially and synthesized using structuring / O presente trabalho relata o estudo de estruturas nanoporosas, visando o uso em pesquisas que atendam a atual demanda da ind?stria do petr?leo, de valorizar ?leos pesados. Inicialmente, optou-se por duas vertentes para a s?ntese de estruturas porosas a partir da peneira molecular do tipo Si-MCM-41. Na primeira vertente, a estrutura MCM-41 ? precursora para hetero?tomos substituintes do sil?cio, gerando catalisadores do tipo Al-MCM-41 a partir de dois diferentes m?todos de incorpora??o do metal. Essa varia??o do m?todo de incorpora??o do Alum?nio na estrutura do Si-MCM-41 se deu atrav?s do procedimento convencional, no qual a fonte de alum?nio foi incorporada ao gel de s?ntese e do procedimento p?s-s?ntese, no qual a fonte de Alum?nio foi incorporada ao catalisador ap?s a s?ntese do Si-MCM-41. Na segunda vertente, o MCM-41 age como suporte para o crescimento de nanocristais de ze?lita embutidos nos seus mesoporos, resultando no catalisador h?brido MCM-41/ZSM-5. Uma an?lise comparativa foi realizada atrav?s de caracteriza??es por XRD, FTIR, medidas de acidez atrav?s de dessor??o de n-butilamina por TGA, SEM-XRF e Adsor??o de N2. Tamb?m foi sintetizado um aluminossilicato cristalino com estrutura zeol?tica MFI do tipo ZSM-5, na aus?ncia total de direcionador org?nico. Metodologias relacionadas ? prepara??o desses materiais s?o relatadas pela literatura utilizando-se convencionalmente reagentes que forne?am os ?xidos de sil?cio e de alum?nio necess?rios, bem como um agente direcionador, e em alguns casos at? co-direcionadores. A busca por novas rotas de prepara??o para a ZSM-5 visou, sobretudo, a otimiza??o da mesma no que se refere ao tempo e ? temperatura de s?ntese, e principalmente a elimina??o do uso dos direcionadores org?nicos, que s?o materiais de alto custo e geralmente muito t?xicos. O atual estudo se baseia na utiliza??o da H2O e dos c?tions Na+ desempenhando o papel de direcionamento estrutural e compensa??o de cargas na estrutura. Caracteriza??es por XRD, FTIR, SEM-XRF e Adsor??o de N2 tamb?m foram realizadas para esse material, a fim de comparar as amostras de ZSM-5 sintetizadas na aus?ncia do direcionador e aquelas utilizadas industrialmente e sintetizadas utilizando estruturantes