CATALYSIS

Author: PÉREZ LORENZO MOISÉS.
Year: 2003.
University: VIGO [www.uvigo.es].
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE QUÍMICA.

Summary: In the wake of the jobs that exist in the literature on the combined use of microemulsiones and phase transfer catalysts in reactions ergánicas in this doctoral thesis contains a study of simultaneous action microemulsiones water oil and glimas on reactions aminólisis.La election of the reaction aminólisis as chemical probe stems from the fact that this process has been studied congran profusion in various media reaction, as well as its catalyst for species such as crown ethers or glimas. The results achieved by studying the mainólisis of p-nitrofenil acetate in microemulsiones of AOT, have allowed us to find two distinct types of behavior: the rate constant aminólisis in microgota aqueous increases with decreasing W, while the constant speed the interface increases with increasing W, This difference in behavior is going to be a consequence of the different properties of water and the microgota aqueous interface, and its ability to separate solvatación of reagents and transitional states of the reaction. On the other hand, the study of aminólisis of P-nitrofenil caprto, has enabled us to analyze quantitatively the combined influence of microemulsiones and phase transfer catalysts for this reaction, as well as draw conclusions on the mechanism of these processes and properties environmental continuum of microemulsion.

Author: ARMAS MARIN NORKA.
Year: 2003.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of defense: Aula de Conferéncias 28.8.ETSEIB.
Place of preparation: ETSEIB, EDIFICI H PLANTA 10 Campus SUD.

Summary: Surplus butanos and pentanos that Venezuela will have a strong incentive to develop new technologies to transform them into higher value-added products through more favorable than those currently available. In the literature review, it became a catalyst based on vanadium and magnesium oxides which allowed visualize the possibility of developing a novel technology for the production of unsaturated hydrocarbons through oxidative dehydrogenation. To realize the development of this technology, it should resort to the use of fluidized bed reactors, or allowing mobile resolve the explosive potential of the mixture hidrocarburos-oxígeno separating the areas of oxidation of hydrocarbon oxidation catalyst, which also offer advantage of a substantial increase in selectivity. As the catalyst available does not meet the necessary characteristics of resistance to attrition intends to resolve the problem by adding an additional support as silica or alumina, material already widely used in reactors of the type mentioned above. The central objective of this work was to cover this part of knowledge in order to optimize the characteristics of the catalyst. Moreover, it was considered appropriate to make an attempt to improve the performance of the active phase by adding new elements, and study the behavior of the most interesting catalysts in the oxidative dehydrogenation of n-pentano order to be able to evaluate the potential extension of the technology. To that end, a set of catalytic converters and built a team that would allow make the necessary experience. In order to be able to interpret the behavior changes that were observed, it was necessary to proceed to characterize the catalysts. The catalytic results obtained relate to the DHOX of n-butane and then n-pentano. Analyzing the impact of the media and of the promoters. Support has been the most studied silica in order to quantify the effect it had on the nature of the medium activity and selectivity, as well as the relationship Mg / V optimal or éfecto dilution of the stand. There was a decrease in activity, while in terms of selectivity changes were observed in the distribution of products, but overall selectivity similar to the pure active phase up to a silica content of 30%. It was found that the catalyst MV4-30 has interesting features around which in the future may develop the technology. Other materials that were incurred for future studies were interesting catalysts Gamma30 and Alfa30. As for the promoters, only studied some (Sb, Bi, Mo and Ga) with interesting results in terms of selectivity. The opportunity was taken to verify the effect of precursor used vanadium, llegándo to confirm the advantages of using oxalate vanadilo. With respect to the oxidative dehydrogenation of n-pentano, there was a behavior similar to that observed with the tanks but with lower olefins selectivity overall .. Finally, to quantify the results and move to a possible reactor design, it became necessary to develop a program that would allow simularlos. This aspect is described in Chapter 5 and is focused on the catalyst MV4-30. The effort was, from our point of view, satisfactory, and left a structure calculation available to be used with other catalysts and 8 jet 29b is at the bank.

Author: FRANCH VACA M. ISABEL.
Year: 2004.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: ESCUELA DE POSTGRADO.

Summary: The photocatalyst heterogeneous looms as one of the new sustainable technologies potentially more efficient for the treatment of non-biodegradable pollutants. This technique is based on the properties fotocatalíticas a semiconductor innocuous as the TiO2. The semiconductor slurry, and low radiation at wavelengths suitable generates radicals capable of mineralizar pollutants biorecalcitrantes, even when they are at low concentrations. However, the implementation of the photocatalyst for heterogeneous wastewater treatment on a large scale requires optimize certain parameters, such as the yield quántico and energy efficiency. The formation of short-chain carboxylic acids during degradation of aromatic compounds, systems fotocatalíticos, it is a fact known but relatively little studied. Maleic acid is a suitable model for studying this type of intermediate mineralization. The results presented in this paper show that the formation of Maleic acid can make a big impact on the performance of an aqueous medium detoxification treated through a process of heterogeneous photocatalyst. Maleic acid compete efficiently by surface adsorption sites of TiO2. Such a capability assumes great mportancia mainly due to two aspects. First, the Maleic acid is a atrapador hole more efficient than surface hydroxyl groups. Secondly, the Maleic acid adsorbed can act as a clearinghouse recombinant pair electrón-hueco, to the detriment photocatalytic the quantum yield. The modification of TiO2 in soft conditions, simply by adsorption of Fe (III) and As (III) proposed in this paper as a metodologiá appropriate to increase the efficiency of the photocatalyst heterogeneous. Both metallic cations for participation oxygen and superoxide radical in the process of mineralization Maleic acid, leading to a degradation more efficient, significantly reducing the recombination torque electrón-hueco on organic substrate adsorbed. The adsorption of Al (III) involves, in addition, a shift of the spectrum of adsorption catalyst towards the visible, potentially allowing better use of sunlight as a source of energy. Moreover, the catalyst modified by adsorption of Al (III) shows properties of great importance to the technological development of the photocatalyst heterogéna. It demonstrates that the presence of Al (III) can help prevent the emergence of the catalyst deactivation phenomena, thus facilitating an effective reuse.

Author: PORRAS MURIEL JUAN MANUEL.
Year: 2004.
University: CÓRDOBA [www.uco.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: The Doctoral Thesis is structured into two distinct parts, corresponding to two Projects Research Department. Organic Chemistry. The first part has been the synthesis, characterization and analysis of the catalytic activity of various systems based on Pt deposited on MgO. For the synthesis of the new systems, based on Mg (OH) 2 commercial has been preparing a support MgO introducing appropriate textual properties to be used as carriers of metals. After the deposition of Pt, in various proportions, through various salts precursor, has been activating the precatalizadores, primarily by reduction with hydrogen. Subsequently there has been the carecterización delos systems using techniques Porosimetría of N2 At 77K, TPR, Quimisorción H2 and CO2, and X-Ray Diffraction Finally, we analyzed the activity and selectivity of the catalysts in reactions "test" with interest in Petroleoquímica, such as dishidrogenación of cyclohexane and the conversion of n-hexane. It has also studied the deactivation of the catalysts in front of pyridine and thiophene added to food. In the second part, have developed methods multirresiduales for the determination of pesticides in olive oil through CG-EM and / or HPLC-EM using metodologíads MS / MS after application of extraction and "clean". These procedures were applied to the most widely used herbicide in the olive groves of Andalusia, which were divided into 4 main groups: 1 .- Compounds polarity media, analyzed by CG-MS/MS or HPLC.MS / MS reversed phase. 2 .- quaternary ammonium salts, analyzed by HPLC-MS/MS of reversed phase. 3 .- Triazoles, analyzed by HPLC-MS/MS of reversed phase. 4 .- Phosphonates amino acid, analyzed by ion chromatography or HPLC-MS/MS of reversed phase. Once optimized methods were applied to the study of real samples, while preserving the anonymity of the same, indicating that, in samples monitored, only compounds polarity medium polluted oil in significant proportion.

Author: MORENO ROJAS JOSE MANUEL.
Year: 2004.
University: CÓRDOBA [www.uco.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: This thesis part of a project in collaboration with the Ministry of Agriculture and Fisheries of the Andalusian linked to the quality of oil Olivaen our region. As a further step in the research has explored the destruction of a herbicide (Fluroxypyr) by Catalysis Heterogénea through two different techniques:-Fotocatálisis: destruction of herbicides by the action of light with a catalyst photosensitive. By studying the process of destruction of herbicide Fluroxypyr both from the point of view kinetic as mecanistico and evaluating the process of mineralization total herbicide. - Hidrogenolisis (hidrodeshalogenación) on metal palladium catalysts supported. For this second technique catalysis were synthesized a series of media-based zirconium oxide, both pure as modifying their properties ácido-básicas by adding alkali metals (lithium, sodium and potassium), to obtain solid subsequently utilízaron as carriers the metal catalysts, which consist of systems consisting of palladium deposited on the stands above. For too full characterization and its application in reactions hidrogenolisis of compuestosrelacionadosestructuralmentecon herbicide Fluroxypyr. Finally, to address studies adulteration in olive oil and possible classifications by appellations of origin was thought of the future implementation of a team of Mass Spectrometry for Stable Isotopes, recently acquired by the UCO. The aprendizajey entry points of the art pyrolysis coupled with IRMS, TC / EA-IRMS and its potential applications are described in the second part of the thesis. Specifically, the application to the detection of the source (natural or synthetic) Acid Tartárico added to the wines, as the addition of acid Tartárico of synthetic origin is an illegal practice recognized by the European Union.

Author: ROLDAN MESA RAFAEL.
Year: 2004.
University: CÓRDOBA [www.uco.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: Doctoral Thesis This includes the study of a series of materials zeolíticos, their properties and applications in various catalytic reactions of industrial interest. The zeolites are aluminosilicates microporosos presenting acidity Bronsted. In addition, its structure consists of channels and voids molecular dimensions (up to 2 nm) for small molecules that can move. These two features make them ideal for use as catalysts in reaccíones controlled by the acidity and / or selectividadde form. In this investigation has been carried out the study of a series of zeolites of different pore sizes and quantity and naturalezade centers acids in the reaction of hidroisomerización of light paraffins. This reaction is highly useful in the oil refining industry, since it is from alcanos linear compounds are obtained isomers more octane number. The zeolites used metal supported (platinum or palladium) are excellent catalysts in this reaction, and their possibilities have been discussed, as well as the reaction mechanism, a way that helps them understand more deeply the mode of action of these materials . To that end, he has also been a need for extensive structural characterization using different techniques and other reacciónde transalquilaciónentre aromatic compounds. On the other hand, have been investigated other materials microporosos character acid, known as silicoaluminofosfatos (SAPOs), in several rooms held abroad. Emphasis has been placed on the synthesis of SAPO-5 with a new agent director of the structure and properties of the samples have been caracterizadasen reaction hidroisomerización of n-heptane.

Author: ROCA MOLINER MARIA TERESA.
Year: 2004.
University: JAUME I DE CASTELLON [www.uji.es].
Place of defense: ESCUELA SUPERIOR DE TECNOLOGIA Y CIENCIAS EXPERIMENTALES.
Place of preparation: ESCUELA SUPERIOR DE TECNOLOGIA Y CIENCIAS EXPERIMENTALES.

Summary: The Doctoral Thesis, is a study of the reaction of transfer between the cofactor S-adenosilmetionian (SAM) and the substrate catecolato through hybrid methodology Quantum Mechanics / Molecular Mechanics (Quatum Mechanical / Molecular Mechanical, QM / MM). Initially, has been explored and characterized the potential energy surface using a combination of programs CHARMM / GRACE and subsequently has won the free energy profile both in the midst enzyme in aqueous solution using the program DYNAMO. After studying the reorganization of the enzyme and substrate on the preorganización of this reaction SN2 has clarified its contribution in catalysis. In addition, from the evolution of the dynamic effect of the reaction has been obtained an estimate of the deviations from the State Theory of Transition and has also been able to explain his contribution in enzymatic catalysis. Finally, there are the Effects Isotópicos Cinéticos calculated and the results obtained are compared with experimental data. The matching values allows us to establish a general methodology of work to carry out the study of chemical reactions in condensed media.

Author: IGLESIAS JUEZ ANA.
Year: 2004.
University: AUTÓNOMA DE MADRID [www.uam.es].
Place of defense: INSTITUTO DE CATÁLISIS Y PETROLEOQUÍMICA ,CSIC,(CAMPUS DE CANTOBLANCO).
Place of preparation: INSTITUTO DE CATÁLISIS Y PETROLEOQUÍMICA.

Summary: The purpose of this study was first analysis of a series of Pd catalysts supported on different materials CeO2/A1203 and Zr, Ce) OxlAI203 to eliminate ca, NO and C3H6 from gasoline engines working conditions estequiométricas (Catalysts of Three Ways). Their catalytic activity was measured on different mixtures of gases in order to assess the effect of the nature of the promoter element containing Ce and determine what are the active centers for each reactant. Particular attention has been paid to the effect of the thermal degradation in the performance of these systems and their response to changes in the redox status of the mixture. On the other hand, traditional catalysts of Three Roads can not be used with internal combustion engines to operate with poor fuel mixtures. In this type of system one of the main lines of research is directed towards the development of a catalyst which is capable of reducing NOx (with hydrocarbons from the fuel) in the presence of a large excess of oxygen. This has been studied two sets of catalysts silver Ag/A1203 with díferentes content by weight, prepared by methods of impregnation and microemulsion. In both thematic motivation main work has been more deeply understand the factors conditioning, the atomic scale, the activity of the catalysts, it has been used for the analysis of chemical and redox behavior of the systems under reaction conditions using studies on the spot using IR spectroscopy in Diffuse Reflectance by Tansformada Fourier (DRIFTS) and Absorption Rays in the Region Close to the Edge (XANES), trying to correlate these data with the results of catalytic activity and key characterization of materials made through a combination of techniques as ex situ diffraction of X-Rays, Microscopy, Transmission Electróníca and Espectroscopías Absorption Rays (XANES and EXAFS), Raman, UV-visible and Resonance paramagnética Electronics.

Author: FERNÁNDEZ HERMIDA CADAHÍA ESPERANZA.
Year: 2004.
University: SANTIAGO DE COMPOSTELA [www.usc.es].
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE QUÍMICA.

Summary: In order to conduct a quantitative interpretation of the influence of microemulsiones in reactivity, it is necessary to know the concentrations of the reactants in different pseudofases system and the corresponding constant speed. To that end, it has devised a kinetic model based on the formalism of pseudofase, in order to explain the reactivity in microemulsiones water in oil. According to the model of the pseudofase the microemulsiones are divided into three regions: water, oil and interface with the movie surfactant delimiting the border between the organic phase and the aqueous phase. Each region is treated as a separate phase of this model to the distribution of reagents, these regions will be determined by their free energy transfer between pseudofases. It is assumed that the transfer speed of these reagents is much faster than the observed rate constant of the reaction. The distribution of reagents describing always through a constant balance over the course of the reaction. A model of the pseudofase has been successfully applied to reactions that occur at the interface of the microemulsion and reactions that take place simultaneously in the aqueous phase and at the interface of the microemulsion, however, has proved its validity when interpreting react to occur in the organic phase and at the interface of a microemulsion. In order to find a reaction than in these two phases has been studied simultaneously reaction Diels-Alder between N-etil maleimida and ciclopentadieno. Because the solubility of these two reagents reaction takes place simultaneously and in the organic phase at the interface of the microemulsion. A model of the pesudofase has been successfully implemented and has been able to determine the rate constant at the interface of the microemulsion. It has been found that the rate constant at the interface is about 350 times smaller than water and about 2 times higher than in isooctano, which is consistent with the properties interfaciales. It also has studied the addition 1,3-dipolar between N-etil maleimida and oxide benzonitrilo, moving reaction to the interface because of the nature of dipolar oxide benzonitrilo. To study the reactions catalyzed by Lewis acids is necessary to know as to affect the microemulsion phase of complexation between the substrate and the metal ion, and then be able to study the reaction itself. In order to learn how to affect the microemulsion complexion has made a study of the thermodynamic and kinetic complexion of a colorant, PADA, with two metal ions Ni +2 and Co +2. It has been found that in both cases the constant complexion to the microemulsion is lower than in aqueous medium and further that such constant decreases with increasing water content in the microemulsion. As for the rate constant training complex Co. +2- PADA is about 50 times higher than the rate constant for the complex formation Neither +2- PADA, which is consistent with the fact that the speed of sharing water for Co +2 is about 75 times higher than in the case of Ni +2. Once studied the complexation process in microemulsiones attempted to synthesize a surfactant that would contraión a metal ion can catalyze reactions. As a preliminary step was obtained HOT, surfactant, which differs from AOT in the HOT presented as contraión a pattern. It was found that surfactant is capable of giving rise to microemulsiones, becoming the first case where a surfactant with the contraión H + leads to such structures. This surfactant was characterized by IR, NMR and it was determined according to its acidity. With 8 so 5fa to know the effect that the change in contraión in surfactant on the reactivity has made a comparative study of solvólisis a series of halides and Benzoyl phenyl clorofomiatos. Finally, we studied the acid catalysis of p-nitrofenil and acetate and p-nitrofenil picolinato in microemulsiones of HOT / isooctano / water aprovechándonos of acid nature of these microemulsiones. It also has studied the reaction of acid hydrolysis of p-nitrofenil picolinato. Hydrolysis of this compound can be catalyzed by metal ions and the ion hidronio, this paper makes a study of the reaction catalyzed by H + in microemulsiones of HOT / isooctano water. To determine the rate constant has been successfully applied the model of the pseudofase.

Author: HERRERÍAS LARRIPA CLARA ISABEL.
Year: 2004.
University: ZARAGOZA [www.unizar.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: This work has been carried out the detention of a complex (oxazolina) -cobre through different strategies that are classified according to the type of interaction between these complexes and the medium used. Such strategies are classified as: -Inmovilización through electrostatic interactions on media such as anionic clays and materials hybrid nafión silica. The possibility of preparing heterogeneous catalysts ion exchange depends mainly on the stability of the complex. In the case of complex not very stable, such as boxing (tBu) -Cu there is a balance between how complejada and free copper. The variation of several parameters such as solvent intercmbio or cation exchange to alter that balance. The use of more Coordinating ligands such as azabis (oxazolinas), leads to the best enantioselectividades found in the reaction of ciclopropanación between styrene and diazoacetato ethyl using a supported catalyst. Moreover, the nature of the solvent used in the reaction can alter the strength of interactions catalizador-soporte. This significantly modifies the catalytic activity, but also on solid nature laminar can totally change the course estereoquímico of the reaction, acting surface of the medium as a new ligand voluminous. - Freezing in ionic liquids: The use of ionic liquids has enabled obtaining recoverable catalysts for reactions catalyzed by a complex (oxazolina) -cobre. The use of ionic liquids is particularly advantageous with respect to solids in the case of anionic complexes used not very stable, because it prevents interactions estéricas between support and chiral ligand. There are several factors that play an important role in the reaction ciclopropanación catalysed by a complex (oxazolina) -cobre in ionic liquids, such as the nature of the anion of ionic liquid, the cation of the ionic liquid, the presence of water, synthetic method and the nature of chiral ligand. - Freezing through covalent bond in organic polymers: The morphology of polymer plays an important role in chemotherapy and estereoselectividades of reactions in which chiral catalysts are used immobilized in polymeric matrices. Using dendrímeros suitable as linking agents to improve the accessibility of the catalytic center, polymers leads to the best properties in terms of ligand economy, improving the transmission of information chirality. The structure of dendrímero and chiral ligand is important to optimize the results. Despite this improvement in the transmission of information chirality, have not improved, in terms of activity, enantioselectividad and recoverability the results obtained with the homopolymers synthesized from a (oxazolinas) funcionalizadas groups p-vinilbencilo. - Freezing through covalent bond in fused silica: a (oxazolinas) can immobilize covalentemente in silica through appropriate funcionalización bridge metilénico center and rear anchor. The nature of the spacer inserted affects the effectiveness of catalyst, being highly dependent influence of the substituents on the ring oxazolina. The sol-gel synthesis, starting from the same precursors for anchorage, an alternative to the grounding of a (oxazolinas) in silica. The textural properties of the solid obtained by sol-gel depend on the nature of chiral precursor, both in the spacer as the ligand. Although the results are not optimal, it has demonstrated the feasibility of this type of immobilization strategy, being necessary optimization of different aspects such as the nature of the spacer and the ligand, the process conditions and the protection of silanoles free. The compression from the effects of support has enabled us to 8 the best resid 36d ra sound of our catalysts. In addition, it should be noted that the effect of support is not necessarily negative, and that can have beneficial effects in the process, not only for recovery.

Author: SERRANO RUIZ JUAN CARLOS.
Year: 2005.
University: ALICANTE [www.ua.es].
Place of defense: ESCUELA POLITÉCNICA SUPERIOR.
Place of preparation: DEPARTAMENTO QUÍMICA FÍSICA.

Summary: This memory Doctoral Thesis seeks to deepen the knowledge of the systems and platino-estaño supported platinum material based on cerium oxide (CeO2-ZrO2, CeO2-Al2O3 and CeO2 / C). The study will focus on the degree of interaction of metal species on the one hand with one another, and another, with the support of cerium oxide, after various treatments reduced (473 and 773 K). With the help of techniques in situ characterization and reaction test "sensitive" to changes after reduction treatments, would yield information on the nature of the active sites on the surface of the catalyst, which will allow a better understanding of catalytic systems under study. Lastly, based on the above information, it will consider a group of catalysts (Pt-Sn/CeO2/C) in two interesting reactions from the industrial point of view: the selective hydrogenation of citral and catalytic dehydrogenation of isobutane.

Author: Ferrer Castillo Silvia.
Year: 2005.
University: VALENCIA [www.uv.es].
Place of defense: Facultat de Químiques.
Place of preparation: Universitat Valencia.

Summary: There has been a theoretical study on the enzyme lactate Deshidrogenasa (LDH), which includes the process of the chemical reaction catalyzed by the enzyme through calculations hybrid QM / MM. These studies include the exploration of the potential energy surface studies, simulations of molecular dynamics, kinetic studies and mutations. It also includes a preliminary study of the reaction catalyzed by the enzyme Dihidrofolato Reductasa (DHFR).

Author: INFANTES MOLINA ANTONIA.
Year: 2005.
University: MÁLAGA [www.uma.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: We have prepared fused silica mesoporosa Doped zirconium using reagents such as sodium silicate economic chloride zirconilo and Triton Z100 (polietilfeniléter). Obteniéndose a number of different materials mesoporosos with textural properties and acidic. Once obtained media, catalysts were prepared by impregnating a fledgling humidity, using salts Co, Mo, W Pt, Pd and Go in different proportions to study the influence of metal content in the dispersion, reducibilidad and activity of the active phase metal. The materials were characterized by XRD, XPS, RTP-H2, quimisorción H2, TEM and elemental analysis, DTP-NH3, pyridine adsorption combined with IR spectroscopy and adsorción - desorción of N2. These catalysts have been tested in the reaction in fixed bed and continuous hydrogenation and opening tetralina to 6 MPa H2 and temperatures between 275 and 375Â ° C. It has studied the effect of gracious reaction temperature, the relationship H2/tetralina and contact time on the conversion and yield towards hydrogenation products and openness. Ultimately, it has sought to obtain catalysts that can improve the performance of diesel fuels to be used as catalysts for hydrogenation of aromatics to reduce the emission of pollutants into the atmosphere and at the same time, as acidic catalysts who open cicloparafinas resulting , thereby increasing the rate of cetano of those fuels.

Author: MIFSUD GRAU MARÍA.
Year: 2006.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: Universidad Politécnica de Valencia.
Place of preparation: Universidad Politécnica de Valencia.

Summary: Concern about environmental issues has made in recent years emerges an entire approach within the chemical, called Sustainable Chemistry, which aims to prevent or minimize pollution from its origin, both industrial and research laboratories. Here, the field of catalysis and especially of heterogeneous catalysis can contribute greatly since it allows both comfortable and safe handling of the reaction as an easy separation, recovery and regeneration of the catalyst possible, in addition to the absence of pollutants discharged with a consequent respect to the environment. This thesis has described the possibilities offered by various heterogeneous catalysts for the production of Fine Chemistry in the field of flavors and fragrances, food and pharmaceutical industry. It has detailed synthesis of the following products with high added value using alternative methods using heterogeneous catalysts: - has been made to synthesize molecules interesting from the point of view as aróma to industrial and melon? -Decalactona Which is a major Sn-Beta / H2O2, which produces only aguacomo product - has also been used solid ground instead of solutions of sodium hydroxide, to carry out the reaction of transesterificación between fatty acid methyl esters and polietilenglicoles, thus avoiding the problems associated with the job homogeneous catalysts such as corrosion of reactors, the need to neutralize the catalyst and the impossibility of being able to be reused has been raised a new synthetic route for the production of Nabumetona, drug with anti-inflammatory activity not Steroid combining two reactions in a process cascade: condensation aldólica-hidrogenación using catalysts trifuncionales - Finally, it has also succeeded in the synthesis of aroma of raspberries

Author: GIL ARRANZ ALFRED.
Year: 2006.
University: ROVIRA I VIRGILI [www.urv.cat].
Place of defense: FACULTAT DE QUIMICA.
Place of preparation: FACULTAT DE QUIMICA.

Summary: In this thesis is a study of the adsorption of molecules on surfaces and metal electrodes. To this end, we used methods that quantum mechanics provides for the analysis of chemical systems by the theory of functional density. The results obtained were compared with the available experimental data and helped interpret them. The study began with the detailed examination of a simple molecule in advance as is the carbon monoxide, then expand the investigation to more complex molecules. We studied the surfaces monocristalinas of Pt (111) and a model of surface bimetálica, Pd / Pt (111), increased use in the field of electrochemistry. It has also developed o2m, a graphical tool for viewing files output VASP 4.5. In contrast, the behavior of less intense bands of the spectrum indicates a decline in coordinating the CO molecule to increase the potential. The results obtained with models electrodes bimetálicos of Pd / Pt (111) confirm that the frequency of tension OC is a very local ownership, only influenced by the metal atoms directly involved in the liaison quimisorción. The shift towards higher frequencies observed by increasing the coating CO is interpreted as a change in the position of adsorption, and not as an effect of potential external, as in the case of platinum electrode. A comprehensive study of the quimisorción of the CO molecule on Pt (111), using newspapers and cluster models, said the position tricoordinada fcc as the active site of adsorption more stable. This finding contradicts numerous experimental studies showing that the adsorption of the CO molecule is on top positions. An analysis of the results indicates that the use of functional B3LYP models well convergidos could assign the top position as the most stable because of a description of the electronic state more realistic than the one obtained with functional PW91. The gap HOMO-LUMO increases with the inclusion of trade in the exact functional, decreasing the interaction of the LUMO adsorbato with states d metal, which was overestimated in the positions more coordinated. The use of a methodology EMG + U also shifts the LUMO of the molecule of CO to higher energies. Later, we studied a system formed by a dissolution of CO2 into contact with electrodes Pt (111) and Pd / Pt (111). In the case of platinum electrode, it is proposed the existence of carbonate and bicarbonate adsorbed on positions short-bridge, with a surface coating which depends on the potential and the pH of the solution. However, the electrode Pd / Pt (111) only detects the presence of bicarbonate across the interval studied potential. The isotopic effects observed in a spectrum band reinforcing the theory of the presence of bicarbonate in the system. Finally, we calculated the structure and the IR spectrum of molecules sulfate, propene and propilsulfato adsorbed on Pt (111). The latter is formed by activation of propene by sulfate molecule. The theoretical IR spectrum shows two peaks that could be used to identify the molecule alquilsulfato. Through a process of oxideshidrogenación later, it forms a oximetalociclo, an intermediate stable in the path of oxidation of propene on Pt (111), which has proposed its structure.

Author: BONILLA SÁNCHEZ ADRIANA.
Year: 2006.
University: BARCELONA [www.ub.es].
Place of defense: UNIVERSIDAD DE BARCELONA.
Place of preparation: UNIVERSIDAD DE BARCELONA.

Summary: Catalytic systems were prepared relevant to their application in reaction dimerización deshidrogenante ethanol to produce ethyl acetate, which is a solvent that can replace other toxic characteristics. The catalytic systems are different preparations each other, the first of which is composed of Pd catalyst powder and CU, supported in a variety of oxides with different characteristics of acidity and redox. The second of these is the catalytic membranes, which are ceramic tubes formed by several layers of different thickness and pore size. The final layer with the pore size is smaller which were deposited phases active Pd and Pd-Zn. This study identified the importance of support and the type of metal sites in the selectivity towards the various products produced in the reaction of dimerización deshidrogenante to produce ethyl acetate. When retrieving metal particles of Pd without interaction with the media were observed high selectivity towards decomposition products of ethanol as CO and CH4. The selectivity towards ethyl acetate was favored supported catalysts to be used in interactions intermetalicas between Pd and species of metal bracket. This effect was also observed in the catalytic membrane systems. When comparing the results obtained with both systems, it was noted that the membranes had a better catalytic selectivity towards ethyl acetate and a lower tendency to decomposition to C1, becoming more efficient reaction.

Author: ARAGON SAEZ PEDRO JOSE.
Year: 2006.
University: CASTILLA-LA MANCHA [www.uclm.es].
Place of defense: FACULTAD DE CIENCIAS QUIMICAS.
Place of preparation: FACULTAD DE CIENCIAS QUIMICAS.

Summary: One of the lines of our group Inestigación studying the synthesis and characterization of new metallocene and non-metallocene complexes and their application in catalytic olefin polymerization, both in homogeneous conditions, as supported. This report has been described on the one hand, the synthesis of five new metallocene complexes kind of a titanium and zirconium, including heterocyclic groups in its formulation. The rationale behind this amendment is in its potential as bases dadoras Lewis, allowing them fixation in a support capacity aceptora. The complexes have been characterized using nuclear magnetic resonance techniques, elemental analysis, and in some cases, through X-ray diffraction of monocristal. It has been extensively studied their activity in polymerization of ethylene, propylene and styrene, homogeneity. These complexes have been set on a stand based on MgC12 partially modified with tetrahydrofuran and a silica-modified metilaluminoxano. These announcements have been characterized by different techniques for the analysis of solids. We have found some of the complex modified with groups giving sets more efficiently than similar complexes without these groups. Also, the catalysts supported in this way presents a suitable polymerization of ethylene, with a low connection aluminum / metal higher than in the complex of reference. It has been studied by spectroscopy UV-Visible, the setting of complex media, as well as the activation process through metilaluminoxano. On the other hand, there are twelve new complex of titanium, not metallocene with ligands alcóxido and tiolato type heterocyclic, which act as ligands "isolated". The complexes have been characterized using nuclear magnetic resonance techniques, elemental analysis, and in some cases, through X-ray diffraction of monocristal. It has been found that several of these complexes act as a catalyst for polymerization sindioespecifica styrene. The report is divided into a section of bibliographic record, which describes the "state of art" of catalytic polymerization of single site, from an academic point of view. Then there is a discussion of results, with a corresponding Experimental Procedure. Finally, it outlines the conclusions obtained from the study.