Chemistry / The efforts described in this thesis were bifurcated along two distinct projects, but generally were directed toward the development of new materials to solve outstanding issues in contemporary electrochemical applications. The first project involved the synthesis and application of redox-switchable olefin metathesis catalysts. N-heterocyclic carbenes (NHCs) bearing ferrocene and other redox-active groups were designed, synthesized, and incorporated into model iridium complexes to evaluate their intrinsic electrochemical and steric parameters. Using these complexes, the ability to switch the electron donating ability of the ligands via redox processes was quantified using a variety of electrochemical and spectroscopic techniques. The donicity was either enhanced or attenutated upon reduction or oxidation of the redox-active group, respectively. The magnitude of the change in donicity upon reduction or oxidation did not vary significantly as a function of the proximity of the redox-active group from the metal center. Thus, other factors, including synthetic considerations, sterics, and redox potential requirements, were determined to guide ligand design. Regardless, redox-active NHCs were adapted into ruthenium-based olefin metathesis catalysts and used to gain control control over various ring-opening metathesis polymerizations and ring-closing metathesis reactions. The second project was focused on the development of new basic polymers for acid/base crosslinked proton exchange membranes intended for applications in direct methanol fuel cells. Polymers containing pendant pyridinyl and pyrimidinyl groups were obtained via the post polymerization functionalization of UDEL® poly(sulfone) and then blended with sulfonated poly(ether ether ketone) (SPEEK). Fuel cells containing these blends were found to exhibit reduced methanol crossover, higher open circuit voltages, and higher maximum power densities compared to plain SPEEK. The differences in fuel cell performance were attributed to the basicity and sterics of the pendant N-heterocycles. / text

<p>The direct methanol fuel cell or DMFC is emerging as a promising alternative energy source for many applications. Developed and developing countries, through research, are fast seeking a cheap and stable supply of energy for an ever-increasing number of energy-consuming portable devices. The research focus is to have DMFCs meeet this need at an affordable cost is problematic. There are means and ways of making this a reality as the DMFC is found to be complementary to secondary batteries when used as a trickle charger, full charger, or in some other hybrid fuel cell combination. The core functioning component is a catalyst containing MEA, where when pure platinum is used, carbon monoxide is the thermodynamic sink and poisons by preventing further reactions at catalytic sites decreasing the life span of the catalyst if the CO is not removed. Research has shown that the bi-functional mechanism of a platinum-ruthenium catalyst is best because methanol dehydrogenates best on platinumand water dehydrogenation is best facilitated on ruthenium. It is also evident that the addition of other metals to that of PtRu/C can make the catalyst more effective and effective and increase the life span even further. In addition to this, my research has attempted to reduce catalyst cost for DMFCs by developing a low-cost manufacturing technique for catalysts, identify potential non-noblel, less expensive metallic systems to form binary, ternary and quarternary catalysts.</p>

Ethylene and propylene are important chemical feedstocks for the production of polyethylene and polypropylene. Ethylene and propylene can be produced by various methods including steam cracking of liquefied natural gas (LNG), naphta or light olefin fractions. The methanol to olefin (MTO) process provides an alternative means of producing ethylene and propylene, where ZSM-5 is frequently used as catalyst due to its hydrophobicity, strong acidity, molecular sieve properties and low tendency towards coking, which makes ZSM-5 one the most popular zeolite catalysts in the industry. The oil crisis 1973 and the second oil crisis in 1978 caused the development of a commercial MTO process. Mobil Research and Development Corporation built a fixed-bed pilot plant to demonstrate the feasibility of the MTO as well as methanol-to-gasoline (MTG) process. When the oil price dropped again during the 1980’s, further developments of commercial processes were stopped for the time being. However, investigations on a bench scale are still pursued, and applications for patents are still submitted. During this study ZSM-5 was synthesized with a hydrothermal method, which produced agglomerated polycrystalline grains with characteristic ZSM-5 morphology and a Si/Al ratio of approximately 40. The synthesis time, synthesis temperature and aging time were varied while keeping all the other synthesis parameters constant in order to determine their influence on crystallite size. The synthesis time was varied between 12-72 hours, synthesis temperature was varied between 130-170°C and aging time between 30-90 minutes. Using SEM to determine crystal size, it was found that a variation in the aging time produced the largest crystallites (average of 21.6μm ± 10.8μm) while also having the largest influence on crystallite size followed by synthesis temperature (average of 13.1μm ± 4.9μm) and finally synthesis time (average of 5.7μm ± 0.4μm). In all cases XRD and SEM confirmed the formation of ZSM-5. To evaluate the as-synthesized ZSM-5 and compare it to a commercial ZSM-5 catalyst, Catalyst A using the MTO process, ZSM-5 was synthesized for 72 hours at 170°C with an aging time of 60 minutes before synthesis. The as-synthesized as well as Catalyst A’s agglomerated polycrystalline grains were sieved into three size fractions: smaller than 75μm, 75-150μm and 150-300μm. All six ZSM-5 fractions of ZSM-5 were used as catalysts for the MTO process in a fixed bed reactor at 400°C, atmospheric pressure and a 20wt% methanol to water feed. At 3.5 hours time on stream (TOS), the intermediate 75-150μm fraction had the highest light olefin selectivity for both the as-synthesized as well as Catalyst A, followed by the 150-300μm fraction and finally the smaller than 75μm fraction with the lowest light olefin selectivity. From this results it is clear that the as-synthesised ZSM-5 did not perform as well as Catalyst A. While the intercrystalline voids of the agglomerated ZSM-5 form second-order pores where self-diffusion is enhanced, the increased diffusional barriers created by the intercrystalline boundaries reduce the diffusion rate, promoting secondary reactions at the strong Brönsted acid sites thereby reducing ethylene and propylene selectivity. Coking reduces access to the Brönsted acid sites and plays a more influencial role for smaller crystallite sizes. Accordingly, the smaller than 75μm fraction had the lowest light olefin selectivity, while the 150-300μm fraction was probably least influenced by coking. The increased pathways for products and reagents in the 150-300μm fraction resulted in more secondary reactions taking place within this catalyst than the 75-150μm fraction explaining the superior performance of the 75-150μm fraction. Since the grain size determines the ratio of the external to the internal surface areas as well as the amount of intercrystalline boundaries in the catalyst, it follows that the catalytic activity and polycrystalline grain size ratio should actually be tailored when optimising the product distribution of the ZSM-5 catalysed MTO process. The as-synthesized ZSM-5 didn’t perform very well when compared to Catalyst A and modification of the synthesis method is recommended. / Thesis (MSc (Chemistry))--North-West University, Potchefstroom Campus, 2012.

Over the last decade a number of potential tracers of massive star (M > 8M ) formation have been put forward. In this thesis I attempt to understand how these tracers relate to one another and attempt to identify the most suitable tracer for future surveys for massive star formation sites. In this thesis we examine a number of these tracers; the Methanol Maser Multi- Beam Survey (MMB), the Red MSX Survey (RMS), the Boston University Five Colleges Radio Astronomical Observatory (BU-FCRAO) Galactic Ring Survey (GRS), the BOLOCAM Galactic Plane Survey (BGPS) and the Perretto &amp; Fuller (P&F) Infrared Dark Cloud (IRDC) Catalogue, in addition to the Cyganowski Extended Green Objects Catalogue. This work employs a bespoke non-circular aperture photometry technique, K=1 Nearest Neighbour Analysis and Minimum Spanning Trees (MSTs) in multi-dimensional parameter space with oversampling, edge weighing, mean edge fracturing and convex hull tting. Additional, new 13CO observations were made of the young infrared cluster BDS[2003] 107 (Bica 107) and its environs. We see that despite not being contained within the GLIMPSE Point Source Archive the bulk of masers have an infrared bright counterpart. Photometry of the counterparts shows that they occupy the same colour spaces as that previously determined in Ellingsen (2006); [3.6]-[4.5]>1 and [8.0]<1. We show that the bulk of RMS MYSOs do not exhibit masing and that a signi cant fraction of MYSOs are not found within the RMS . Additionally, we see that the EGO RMS association rate is higher than expected. The BGPS, GRS and P&amp;F IRDC exhibit clustering and elongating, with a common characteristic clustering scale of the order of 6 8 pc. We see that the BGPS is more strongly associated with massive star formation than the GRS. Additionally, we see that although in general all three hull types occupy similar co-located spatial positions they also appear as isolated hulls. The analysis of Bica 107 shows that it is part of a larger star forming region containing Bica 108 and the ultra compact HII region, G5.89. The maser associated with Bica 107 appears to lie on the edge of the cluster's expanding CO shell. The observation that the IRAC colour-magnitude occupied by the masers from the Ellingsen sample is consistent with the MMB, sample suggest that these objects have broadly consistent colours during their masing phase. This can be attributed to the dust and gas envelope being radiatively dominant. The cross matching results indicate that the majority of MYSOs do not exhibit masing. The RMS appears to be missing MYSOs due to missing sources in the MSX catalogue and a photospheric bluing due to MSX large beam width, moving candidates outside the RMS colour cut. The RMS EGO relationship appears to be inconsistent with observed MYSO evolution and may be indicative of multiple EGO generation mechanism as suggested by De Buizer and Vacca (2010). The BPGS and GRS objects and IRDCs do not appear to form a star formation sequence and their existence is not necessarily an indicator of on-going star formation; rather they are an indication of the potential for star formation. All three species types showing signs of clustering and elongation. The shared characteristic scale is suggestive that there may be a processes acting below the scale of the GMC but above that of a single star forming region. The maser associated with Bica 107 appears to be either an example of triggered star formation or late onset star formation within the region and is not an example of continuing star formation within Bica 107. We conclude that a GLIMPSE based colour-selected survey, with follow-up observation to reduce contamination, would be the most appropriate method for identifying MYSOs, given the reliability of the tracers examined in this thesis.

OF THE THESIS Name: Bc. Veronika Coufalová, DiS. Specialization: Adictology Head of the thesis: Mgr. Jaroslav Vacek Opponent: Ing., Mgr., Bc. Vendula Běláčková Pages: 83 The name of the thesis: EFFECT OF PARTIAL PROHIBITION ON RESTAURANTS FROM THE PERSPECTIVE OF EMPLOYEES: A QUALITATIVE INVESTIGATION This thesis deals with how the prohibition reflected in the attitudes and behavior of employees and the behavior of consumers in restaurants and bars. The theoretical part is focused on the main substances alcohol and methanol, next on the related topics methanol cases and related facts in criminology. Another chapter is aimed at the prohibition in the country. The research was carried out through qualitative methods of data collection, which was formulated in the form of interviews, which were designed according to the draft of the questionnaire. This research was anonymous, respondents were informed of the ethical rules and the possibility of withdrawing from the research file. Next were used methods expert estimates for research changes in behavior and the method of triangulation. In the research was included 30 restaurants and bars selected nomination technique. Results are evaluated on the basis of data transferred from the audio recording into Excel spreadsheets, where it was possible to insert...

O estudo da variação de massa na superfície do eletrodo pode fornecer importantes informações a respeito de processos interfaciais. Quando bem interpretados, os resultados podem auxiliar na elucidação do mecanismo reacional. Assim, aspectos como adsorção de espécies eletroativas, formação e oxidação de adsorbatos, e processos de transferência de carga e sua dependência com o potencial podem ser avaliados. O aparecimento de instabilidades cinéticas em sistemas eletroquímicos, em particular durante a eletro-oxidação de moléculas orgânicas pequenas, tem sido tema de vários estudos. A eletro-oxidação de metanol foi estuda sobre platina em meios alcalino e ácido utilizando a técnica de nanobalança eletroquímica a cristal de quartzo. Os cátions de metais alcalinos têm um papel muito importante sobre os processos eletródicos, influenciando a formação de PtO e a corrente de oxidação do combustível. A oxidação da superfície em KOH é favorecida em relação ao LiOH e a variação de massa para esse processo é maior no primeiro caso. Contudo, a massa molar calculada para espécies oxigenadas na superfície foi maior para a solução contendo LiOH. Para verificar a interação da superfície de platina oxidada com o orgânico foram realizadas medidas de potencial de circuito aberto e verificou-se que na solução contendo íons Li+ o tempo que antecede a íngreme queda de potencial foi maior, sendo a variação de massa durante o transiente de -69,0 ng.cm-2 e -62,3 ng.cm-2 para as soluções de hidróxido de potássio aquoso e hidróxido de lítio aquoso, respectivamente. Nos experimentos conduzidos em meio ácido o foco foi estudar a variação de massa durante as oscilações em condições galvanostáticas. Verificou-se que essa variação de massa foi muito pequena, cerca de 4,7 ng.cm-2, quando utilizado eletrólito aquoso de ácido sulfúrico, e com resolução relativamente boa. Em seguida etapa foi estudada a eletro-oxidação do metanol em solução de ácido perclórico na ausência e na presença de íons cloreto, sobre platina. A oxidação da superfície de plantina é adiada para potenciais um pouco mais elevado na solução contendo cloreto do que em relação àquela sem estes íons. Após a adição de metanol foi realizada uma estimativa do recobrimento de óxido na superfície para as duas situações em questão. O valor de &theta;O encontrado foi de 3,1 e de 3,4 para a solução sem cloreto e com cloreto, respectivamente. Nos experimentos galvanostáticos, verificou-se que as oscilações de potencial e massa apresentaram frequência maior quando havia íons Cl- na solução. Com os experimentos de nanogravimetria foi possível calcular a variação de &theta;CO durante uma oscilação. Os valores obtidos foram 0,08 e 0,12 para a solução com e sem cloreto, respectivamente. Em uma última etapa, o eletrodo foi polarizado em 1,4 V durante 300 s e em seguida abriu-se o circuito e esperou-se até que atingisse o potencial de equilíbrio. Foi observado que o tempo para que este potencial fosse atingido foi de 9,1 s para solução sem cloreto e de 31 s para aquela contendo os ânions. Além disso, foi calculado o valor de &theta;O para as duas soluções. Para a primeira o valor foi de 4,2 e para a segunda foi de 5,1. Os íons cloreto influenciam o processo de redução do óxido nos experimentos de potencial de circuito aberto durante todo o transiente devido o processo de quimissorção que ocorre e a competição com as moléculas de metanol por sítios livres. Este fenômeno também é, possivelmente, responsável pela maior variação de massa observada no transiente e consequentemente no valor de &theta;O. / The study of the mass variation on the surface of the electrode can provide important information about interfacial processes. If there is a good interpretation, the results may aid in the elucidation of the reaction mechanism. So, aspects like adsorption of electroactive species, formation and oxidation of adsorbents, load transfer processes and their dependence on potential can be evaluated. The appearance of kinetic instabilities in electrochemical systems, particularly during the electro-oxidation of small organic molecules, has been the subject of several studies. The electro-oxidation of methanol was studied on platinum in alkaline and acid media using the technique of nanobalance electrochemical scale to quartz crystal. The alkali metal cations have a very important role on the electrodes processes, influencing the formation of PtO and the oxidation current of the fuel. The oxidation of the KOH surface is favored in relation to LiOH and the mass variation for this process is greater in the first case. However, the calculated molar mass for oxygenated species on the surface was higher for the solution containing LiOH. To verify the interaction of the oxidized platinum surface with the organic, open-circuit potential measurements were performed and it was found that in the solution containing Li+ ions the time before the steep drop in potential was greater, corresponding during the transient mass variation of -69.0 ng.cm-2 and - 62.3 ng.cm-2 for the solutions of aqueous potassium hydroxide and aqueous lithium hydroxide, respectively. In the acid experiments, the focus was to study the mass variation during oscillations under galvanostatic conditions. It was noted that this variation of mass it was very small, about 4.7 ng.cm-2, when aqueous sulfuric acid electrolyte was used, and with relatively good resolution. Then, the electro-oxidation of methanol in solution of perchloric acid in the absence and presence of chloride ions on platinum was studied. The oxidation of the plantine surface is delayed to potentials a little more high in the solution containing chloride than in relation to that without these ions, After the addition of methanol an estimation of the coating of oxidation in the surface was realized for the two situations in question. The value of &theta;O found was 3.1 and 3.4 for the solution without chloride and with chloride, respectively. In the galvanostatic experiments, it was verified that the oscillations of potential and mass presented higher frequency when there were Cl- ions in the solution. With the nanogravimetry experiments, it was possible to calculate the variation of &theta;CO during an oscillation. The values obtained were 0.08 and 0.12 for the solution with and without chloride, respectively. In a final step, the electrode was polarized at 1.4 V for 300 s and then the circuit was opened and waited until it reached equilibrium potential. It was observed that the time for this potential to be reached was 9.1 s for solution without chloride and 31 s for the one containing the anions. In addition, the value of &theta;O was calculated for the two solutions. For the first, the value was 4.2 and for the second it was 5.1. The chloride ions influence in the oxidation reduction process in open circuit potential experiments throughout the transient due to the chemisorption process that occurs and competition with the methanol molecules through free sites. This phenomenon is also possibly responsible for the mass observed in the transient and consequently in the value of &theta;O.

Catalysts are involved in a very large number of processes leading to the production of industrial chemicals, fuels, pharmaceutical, and to the avoidance, as well as the clean-up of environmental pollutants. In respect to the latter aspect, efforts are being made by different stake-holders (governments, researchers, industrials, etc) in order to prevent or to minimize pollution of our cities. A notably way to reduce pollution for a friendly environment is to make use of clean fuels. After years of research work, it is only recently that dimethyl ether alone or when combined with methanol has been identified as a potential alternative clean fuel. Nonetheless, the technology used for the methanol synthesis from syngas requires high pressure (>120 atm) to reach an acceptable CO conversion. The dimethyl ether production from methanol in a separate unit makes DME more expensive than methanol. However, the transformation of syngas directly into dimethyl ether can be used to relieve the thermodynamic constraints requiring operation at high pressure. If the synthesis of methanol and dimethyl ether takes place in the same reactor, the process should, in principle, be able to operate at a much lower pressure, making it a potentially cheaper process to produce methanol and dimethyl ether. The catalysts that need to be used for this coproduction have to be catalytically stable, selective and able to catalyze the main reactions (methanol and dimethyl ether synthesis) involved in this process at the same temperature. Unfortunately, existing commercial methanol/DME catalysts are not able to function efficiently in the presence of large concentrations of water or at high temperature. Thus, it is relevant to have a catalyst satisfying the above criteria. Recently, it has been reported that a supported gold catalyst could be used for methanol synthesis; accordingly this study has developed bifunctional gold-based catalysts for the methanol and DME synthesis. This study utilized process synthesis approach to determine the optimal operating conditions for methanol/dimethyl ether production that yielded results used to drive an experimental programme to get the most useful information for designing a process route. In a comparative way and by using the feed compressor work load per unit of valuable material generated as objective function, this study showed that the system where methanol is co-produced with DME is more efficient than the one involving the production of methanol alone and this is applicable for the operating reactor temperatures of 500-700K and the loop pressure ranging from 10 to 100 atm. The catalysts systems chosen in this study were consisted in the physical mixture of gold-based catalysts incorporating respectively gamma-alumina and zeolite-Y. The gold-based catalysts were prepared by a co-precipitation method, then characterized by XRD, Raman Spectrometry and Transmission Electron Microscopy and, afterwards tested using a 1/4 inch tubular fixed bed reactor between 573 and 673K at 25 atm. Amongst the catalysts tested at 673K, and 25 atm, 5%Au/ZnO/γ-Al2O3 produced both methanol and dimethyl ether with moderate yield, whereas 5%Au/ZnO/LZ Y-52 gave high dimethyl ether selectivity (75.7%) with a production rate of 252.3 μmol.h-1.g -1 cat . The presence of hydrocarbons detected by the GC-FID in the gas products requires that further investigations be done to determine the eventual source and optimize this new catalyst system based on gold for a large scale coproduction of methanol and dimethyl ether from syngas.

A Thesis submitted to the faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy / Thermodynamic analysis techniques for the study of combustion in compression ignition engines were developed and refined. The techniques were validated against test runs of diesel fuelling, and were then applied to the almost unexplored case of combustion of aspirated dimethyl either (DME) acting as ignition promotor and supplementary fuel, and injected methanol as main fuel. Combustion chamber pressure versus crank angle data were captured for single engine cycle on normal fuelling (methanol and DME), fuelling with DME alone and pure motoring (no fuel) all at essentially identical engine conditions. These data were analysed by a number of mutually complementary techniques. / AC2017

A sociedade moderna depende integralmente da produção e consumo de energia em seu dia a dia desde cozinhar, ter energia elétrica, transporte, e para processos industriais. O aumento da demanda de energia elevou também os níveis de poluição, o que produz efeitos diretos na saúde do homem. Desta forma, o homem tem que pesquisar novas formas de energia, que em condições ideais, deve ser gerada de forma limpa. Uma alternativa para que se possa enfrentar este problema é a conversão eletroquímica de energia, a qual pode ser realizada de forma eficiente e limpa através das células a combustível. Existe um interesse muito grande em células que oxidam metanol como combustível, para a aplicação em veículos e equipamentos portáteis. No entanto, para se implementar estas células, é necessário um grande progresso na caracterização dos fenômenos eletródicos associados a esta reação, tanto em nível fundamental quanto tecnológico. No presente trabalho foram desenvolvidos catalisadores de PtW, PtOs, PtRuW, PtWOs, suportados em carbono de alta área superficial, para a oxidação de metanol. Os catalisadores foram preparados através da redução por ácido fórmico e através do método de Bonnëmann. As composições dos materiais foram determinadas por EDX. O tamanho médio das partículas foi obtido por TEM, e foi comparado ao tamanho médio dos cristalitos à partir dos difratogramas de raios X. Os estudos eletroquímicos foram realizados através de voltametrias cíclicas e curvas corrente potencial de estado estacionário utilizando-se a técnica do eletrodo de camada fina porosa. Foram feitas também medidas de EXAFS nos catalisadores mais promissores. Os catalisadores possuem atividade na faixa de potencial de interesse, e foram feitos alguns testes em células a combustível. / Modern society integrally depends on the production and consumption of energy for its activities like cooking, lighting and transportation and also for industrial processes. The increase in the demand for energy increases the levels of pollution, which has a direct negative effect in human health. Thus, it is imperative to search for new power sources which, under ideal conditions, do not pollute the environment. One of the alternatives to attack this problem is the electrochemical energy conversion of chemical energy into electricity which can be carried out in an efficient and clean way with fuel cells. Presently, there is a great interest in fuel cells that oxidize methanol directly, for application in vehicles, portable devices and distributed generation. To make these cells a reality it is still necessary much progress in the understanding of the electrodic phenomena associated to the oxidation of methanol, and in the development of suitable electrocatalysts, at both the fundamental and the technological levels. In this work, PtW; PtOs, PtRuW and PtWOs eletrocatalysts, supported on high surface area carbon, for the direct oxidation of methanol were developed. The catalysts were prepared by reduction with formic acid of the corresponding precursors and by Bonnëmann´s method. Their composition was determined by XRD. The average particle size was determined from TEM, and the results compared to crystallite sizes determined from x-ray diffractograms. The electrochemical studies were carried out with cyclic voltammetry and steady state polarization curves using the thin porous coating electrode technique. Some catalysts were also studied by the EXAFS technique. The catalysts prepared show activity in the potential region of interest, and some of then were tested in single fuel cells.

O gás de síntese (Syngas), proveniente do biogás gerado no tratamento anaeróbio de águas residuárias e o CO2 (presente no biogás) surgem como fontes promissoras para a obtenção de produtos de valor agregado nomeados C2-C4, tais como eteno, propileno, butano, metanol e dimetil éter (DME). Neste trabalho, catalisadores de Cu suportados em argila pilarizada foram estudados visando à produção de compostos C2-C4 a partir da hidrogenação do CO e CO2. Da mesma forma, buscou-se otimizar estes catalisadores, tanto para o processo de Fischer-Tropsch quanto para a síntese direta do DME. Primeiramente, foi avaliado o efeito dos agentes pilarizantes Al e Nb para a conversão do metanol em produtos C2-C4. Após a seleção do agente pilarizante, avaliou-se o efeito do teor de cobre (5% e 10% em massa) no catalisador bifuncional de CuZn/V-Al PILC. Finalmente, foi realizada a adição de Ce, Nb, Fe e/ou Co (5% em massa) sobre o catalisador contendo 10% de Cu suportado na argila pilarizada V-Al PILC. As reações de conversão do metanol foram realizadas em temperaturas de 250 ºC - 400 ºC/2h, sob o fluxo de 1,1 mL.h-1. As reações de hidrogenação (CO e CO2) foram realizadas nas temperaturas de 250 ºC e 300 ºC/3h, P= 40 bar e razão de H2/CO=2 e H2/CO2=3. Os catalisadores foram caracterizadas por difração de raios X (DRX) in situ e ex situ, refinamento de Rietveld, fisissorção de N2, análise da composição química (EDX), microscopia eletrônica de varredura (MEV), redução a temperatura programada (RTP-H2), oxidação do cobre com N2O (TPD-N2O), adsorção de piridina gasosa como molécula modelo para a identificação dos sítios ácidos através do FTIR (FTIR-Py), dessorção de amônia a temperatura programada (DTP- NH3), espectroscopia de absorção de raios X e espectroscopia de fotoelétrons excitados por raios X (XPS). O processo de pilarização somado à impregnação de Cu juntamente com Zn, Ce, Nb, Fe e/ou Co produziu catalisadores com diferentes propriedades estruturais e ácidas, as quais favoreceram as conversões do CO e CO2 para produtos C2-C4. O catalisador bimetálico CuFe/V-Al PILC foi o mais ativo em ambas reações de hidrogenação (CO e CO2) e o mais seletivo para a síntese de DME. Os estudos de caracterização mostraram que a baixa seletividade apresentada para a formação de DME está relacionada com a baixa densidade total de sítios ácidos e com a elevada velocidade espacial experimental. / Syngas, a gas mixture produced from biogas generated in the anaerobic treatment of wastewaters, and carbon dioxide (CO2), a biogas constituent, are promising feedstocks for obtaining value-added chemicals known as C2-C4 products, which include ethylene, propylene, butane, methanol, and dimethyl ether (DME). In this work, Cu catalysts supported on pillared clay were studied aiming at producing C2-C4 compounds from hydrogenation of CO and CO2. The studies were conducted toward optimizing the catalysts performance both for Fischer-Tropsch process and direct synthesis of DME. First, the effect of Al and Nb pillared agents on the conversion of methanol to C2-C4 products was evaluated. The pillared agent was selected and further used to evaluate the Cu content (5 to 10 wt.%) effect on the bifunctional CuZn/V Al-PILC catalyst. Finally, the addition of Ce, Nb, Fe and/or Co (5 wt.%) to the 10 wt.% Cu-containing catalyst supported on V-Al PILC pillared clay was studied. The methanol conversion was performed in the temperature range 250 - 400 °C for 2 h under flow of 1.1 mL h-1. The CO and CO2 hydrogenation reactions were carried out at 250 °C and 300 °C, respectively, for 3 h and P = 40 bar using ratios H2/CO = 2 and H2/CO2 = 3. The catalysts were characterized by means of in situ and ex situ X-ray diffraction (XRD), Rietveld refinement, N2 physisorption, chemical composition analysis (EDX), scanning electron microscopy (SEM), temperature-programmed reduction (TPR-H2), Cu oxidation with N2O (TPD-N2O) pyridine adsorption-FTIR spectroscopy (FTIR-Py), temperature-programmed NH3 desorption (TPD-NH3), and X-ray photoelectron spectroscopy (XPS). The pillaring process along with impregnation of Cu with Zn, Ce, Nb, Fe and/or Co produced catalysts with different structural and acidity properties, which favored the conversion of CO and CO2 into C2 -C4 products. The bimetallic CuFe/V-Al-PILC catalyst presented the highest catalytic activity on the CO and CO2 hydrogenation reactions, and best selectivity for DME synthesis. The low selectivity for obtaining DME was revealed to be most likely due to low total acid sites density of catalysts and high experimental spatial velocity.