The aim is to produce aliphatic liquid hydrocarbons using heterogeneous ethylene oligomerization. Thiscould potentially produce renewable synthetic fuels. Heterogeneous catalysis has some advantages overhomogeneous catalysis regarding some sustainability aspects. To achieve this, a setup was built using a heatedfixed bed reactor with an in-situ has chromatography to study conversion and gaseous products, and ex-situGC as well as NMR for analyzing liquid products. Ethylene was oligomerized on a commercial ZSM-5 zeoliteunder varying temperature conditions and feed gas dilution with hydrogen or helium. The gas and liquidproducts were analyzed and evaluated. Additionally, the ZSM-5 was studied at different silica to alumina ratios. The thesis discusses how conversion, liquid yield and selectivity of gas products using GC together withanalysis of liquid products using H-NMR can be used as a simple and quick evaluation. The liquid product isevaluated by the distribution of olefinic and aromatic hydrocarbon species using the hydrogen signal area inthe characteristic chemical shifts of olefinic and aromatic hydrogen. At 250-400oC, 6 bar of ethylene, with andwithout feed dilution, and WHSV of 204 h-1, conversion was consistently above 95% for the diluted 400oCruns. Though the liquid yield fell to around 6%, compared to the best yield at 18% for the pure 300oC run.Diluting the feed had a positive effect on increasing olefinic hydrogen signal while decreasing aromatichydrogen signal. The difference between diluting with H2 or helium had a surprisingly small effect. Decreasingthe Si/Al ratio had no significant effect on performance, while increasing the Si/Al ratio made the zeolite loseits catalytic ability. With a pure ethylene feed the lowest aromatic hydrogen signal was found at 350oC, whilethe olefinic signal did not vary too much with temperature. With diluted feed the higher temperature did leadto a lower olefinic hydrogen signal and higher aromatic hydrogen signal.

The abstract is the summary of three different projects all centered around the generalidea of catalysis which is the general theme of research in the Michaelis laboratory. The firstproject focuses on development of a new heterogeneous catalyst for selective catalysis. In theMichaelis lab, we were interested in the potential of nanoparticle catalysts for regioselectivetransformations. We showed that polymer supported ruthenium nanoparticles performed as areliable catalyst for regioselective reduction of azide to amine. In our study of regioselectivereduction of multiple azide containing substrates, we observed that in presence of ourruthenium nanoparticle catalysts, the least sterically hindered azide group reduced to aminefunctional group. The results were complementary to the conventional methods that employtriphenyl phosphine (Staudinger reaction) as the reductant and target the most electronicallyactive azide group.In the second project, we were looking to develop a new class of hetero-bimetallicNickel-Titanium complexes as an efficient catalyst for organic transformations. We designedand synthesized numerous bidentate ligands including NHC-Phosphine ligand. Our kineticstudies on the Suzuki cross coupling of allylic alcohols and phenyl boronic esters showed thatthe bidentate nature of the ligand was necessary for the success of the catalytic process. Theligand was proved to stabilize the catalyst in the solution by increasing the lifetime of thenickel (0) in the reaction medium. We also discovered a new cooperative titanium-nickelsystem for mild allylic amination of allyl alcohols. The system also represents an idealcatalyst for tandem cyclization amination process.In the Michaelis lab, we were also interested to explore the ability of bimetalliccomplexes in C-H functionalization process. Our efforts in this project led to the discovery ofnew Pallladium dimer complexes with two palladium centers in oxidation state of (I). Thecatalyst showed unique reactivity in C-C bond activation/functionalization. We have alsodiscovered that in presence of catalytic amount of triflic acid and stoichiometric amount ofphenyl boronic acid, cinnamyl alcohol undergoes a boron template dimerization/cyclization.The reaction represents a great synthetic pathway for the synthsis of bis homoallylic alcohols.

The reaction barrier and heat of formation of the various dehydrogenation reactions involved in the steam reforming of ethane is a critical concern in the applications and understanding of these reactions. Focusing on Ir-based catalyst, we report a comprehensive reaction network of dehydrogenation of ethane on Ir(100) based on extensive density functional theory calculations performed on 10 C-H bond cleavage reactions, utilizing the Vienna Ab Initio Package codes. The geometric and electronic structures of the adsorption of C2Hx species with corresponding transition-state structures is reported. We found that the C-H bond in CH3C required the most energy to activate, due to the most stable four-fold hollow adsorption site configuration. Ethane can easily dissociate to CH3CH and CH2CH2 on Ir(100) and further investigation of surface temperature dependence will contribute to the research effort in this area. By using the degree of dehydrogenation of the reactant species as a variable to correlate the C-H bond cleavage barrier as well as reaction energy. DFT studies reveal that the surface Ir(100) to a great extent promotes ethane dehydrogenation when compared to other surfaces.

The hydroformylation of olefins is one of the most important homogeneously catalyzed processes in industry to produce bulk chemicals. Despite the high catalytic activities and selectivity’s using rhodium-based homogeneous hydroformylation catalysts, catalyst recovery and recycling from the reaction mixture remain a challenging topic on a process level. Therefore, technical solutions involving alternate approaches with heterogeneous catalysts for the conversion of olefins into aldehydes have been considered and research activities have addressed the synthesis and development of heterogeneous rhodium-based hydroformylation catalysts. Different strategies were pursued by different groups of authors, such as the deposition of molecular rhodium complexes, metallic rhodium nanoparticles and single-atom catalysts on a solid support as well as rhodium complexes present in supported liquids. An overview of the recent developments made in the area of the heterogenization of homogeneous rhodium catalysts and their application in the hydroformylation of short-chain olefins is given. A special focus is laid on the mechanistic understanding of the heterogeneously catalyzed reactions at a molecular level in order to provide a guide for the future design of rhodium-based heterogeneous hydroformylation catalysts.

Regardless of the simplicity in molecular structure, polyethylene is used in high-performance applications such as medical prostheses and ballistics. Recent advancements in homogeneous catalysis produced UHMWPE in the low-entangled or dis-entangled state that allowed solvent-free-solid-state processing to achieve ultimate mechanical properties ever achieved for a synthetic polymer. Although several homogeneous complexes are known to produce dis-UHMWPE, existing major challenges are uncontrolled nascent polymer morphology, as a consequence reactor fouling/wall sheeting. In such a scenario, a heterogeneous catalyst that can produce dis-UHWMPE to an extent that the characteristics and properties equivalent to that obtained in homogeneous condition, remains an open challenge. The thesis will discuss the know-how for the synthesis of dis-UHMWPE via heterogeneous route to facilitate industrial production by following fundamental understanding of polymerization catalysis, physics, processing, and testing. In this thesis, in-situ formed nano activator/support MgClx/EtnAly(2-ethyl-1-hexoxide)z is employed with a highly active bis[N-(3-tert-butylsalicylidene)pentafluoroanilinato] titanium (IV) dichloride (Cat. 1) for synthesis of dis-UHMWPE. In addition, the relatively easy formation of the MgClx/RnClmAly(OR’) activators/supports allows tailoring by the selection of different aluminum-alkyls and alcohols, giving access to a variety of co-catalysts. This investigation resulted in UHMWPE having Mw from 3 to an unprecedented 43 M g/mol and Ð from 3 to 38 with very high activities up to 2750 kgPE molcat.-1 bar-1 h-1. The adopted route resulted in nano-support that allows tailoring of the entangled state and control over the nascent morphology without reactor fouling, thus providing feasibility of pursuing the polymerization via a continuous process. The nascent polymer shows formation of single crystals of linear UHMWPE and is suggestive of the low-entangled state. The topological differences, with the commercial entangled sample, are identified solid-state NMR, DSC, and rheology. The disentangled crystals allowed desired chain orientation for securing unprecedented tensile modulus (>200 N/tex) and tensile strength (>4.0 N/tex) via solid-state processing. Additionally, the investigation of creep response in the uniaxial tapes has revealed strong influence of molecular weight and entanglement density. These unique characteristics and unprecedented mechanical properties are equivalent to that perceived using a homogeneous catalysis and are the first of their kind achieved for a polymer synthesized using a heterogeneous catalysis.

[ES] En la presente tesis doctoral se ha llevado a cabo un estudio de nuevas reacciones orgánicas de interés catalizadas por diferentes especies de paladio, tanto clústeres como complejos metálicos. En primer lugar, se ha estudiado la reacción intramolecular regioirregular de Mizoroki-Heck catalizada por clústeres de paladio en disolución, donde se han puesto en conflicto las propiedades electrónicas y estéricas de la reacción de Mizoroki-Heck, obteniendo la reacción de ciclación con una regioselectividad inversa. También se han realizado estudios mecanísticos mediante experimentos cinéticos y computacionales. También se ha desarrollado un catalizador sólido basado en una zeolita, concretamente la zeolita X, que tras intercambiar los cationes de compensación de carga e introducir el Pd, cataliza la reacción intermolecular de Mizoroki-Heck regioirregular. Se ha conseguido obtener un centro activo en la zeolita con las condiciones tanto estéricas como electrónicas óptimas para realizar la reacción intermolecular regioirregular de Mizoroki-Heck entre estirenos y iodobencenos, con buenos rendimientos y selectividades. Por otro lado, se ha estudiado una nueva ruta de síntesis de una fragancia comercial, la deshidromuscona, donde se obtiene un rendimiento global de síntesis mayor que el obtenido actualmente en la industria, todo ello en un menor número de pasos. Se ha llevado a cabo un estudio más intenso sobre el paso donde se realiza la macrociclación en alta concentración, para poder ser viable industrialmente. Mediante la reacción de Mizoroki-Heck estudiada arriba, se ha llevado a cabo un estudio de macrociclación a alta concentración donde, a partir de unos sustratos modelo, se realiza la reacción de macrociclación catalizada por clústeres de paladio en disolución, y se obtienen los macrociclos con buenos rendimientos en una concentración de hasta 1M. También se han realizado estudios mecanísticos tanto computacionales como cinéticos. Por último, se ha realizado la síntesis de dos fosfinas voluminosas basadas en una fragancia, y su posterior estudio de coordinación con el paladio y su alcance catalítico en reacciones orgánicas de interés, como son la telomerización de isopreno, y las reacciones de acoplamiento Buchwald-Hartwig y Suzuki con cloroderivados, donde se comprueba la capacidad catalítica de los complejos formados con nuestras fosfinas y el paladio. / [CA] En la present tesi doctoral s'ha dut a terme un estudi de noves reaccions orgàniques d'interés catalitzades per diferents espècies de pal·ladi, tant clústers com complexos metàl·lics. En primer lloc, s'ha estudiat la reacció intramolecular regioirregular de Mizoroki- Heck catalitzada per clústers de pal·ladi en dissolució, on s'han posat en contrast les propietats electròniques i estèriques de la reacció de Mizoroki-Heck obtenint la reacció de ciclació amb una regioselectivitat inversa. També s'han realitzat estudis mecanístics mitjançant estudis cinètics i computacionals. També s'ha desenvolupat un catalitzador sòlid basat en zeolita, concretament la zeolita X, que després de fer-li intercanvi de cations i introduir el Pd que catalitza la reacció a l'interior, s'ha aconseguit obtindre un centre actiu amb les condicions tant estèriques com electròniques òptimes per a realitzar la reacció intermolecular regioirregular de Mizoroki-Heck entre estirens i iodobencenos amb bons rendiments i selectivitats. D'altra banda, s'ha estudiat una nova ruta de síntesi d'una fragància comercial, la deshidromuscona, on s'obté un rendiment global de síntesi major que l'obtingut actualment en la indústria, tot això en un menor nombre de passos, on s'ha dut a terme un estudi més intens d'un pas on es realitza una macrociclació en alta concentració per a poder ser viable industrialment. Mitjançant la reacció de Mizoroki-Heck estudiada anteriorment, s'ha dut a terme un estudi de macrociclació en alta concentració on a partir uns substrats model es realitza la reacció de macrociclació catalitzada per clústers de pal·ladi en dissolució on s'obtenen els macrocicles amb bons rendiments en una concentració fins del 1M. També s'han realitzat estudis mecanístics tant computacionals com cinètics. Finalment, s'ha realitzat la síntesi de dues fosfines voluminoses basades en fragàncies i el seu posterior estudi de coordinació amb el pal·ladi i el seu abast catalític en reaccions orgàniques difícils, com són la telomerización, la Buchwald-Hartwig o la Suzuki, comprovant la capacitat catalítica dels complexos formats amb les nostres fosfines i el pal·ladi. / [EN] In this doctoral thesis, a study of new organic reactions of interest catalyzed by different palladium species, both clusters and metal complexes, has been carried out. Firstly, the intramolecular regioirregular Mizoroki-Heck reaction catalyzed by palladium clusters in solution has been studied, where the electronic and steric properties of the Mizoroki-Heck reaction have been contrasted, obtaining the cyclization reaction with an inverse regioselectivity. Mechanistic studies have also been carried out by kinetic and computational studies. A solid catalyst based on a zeolite has also been developed, specifically zeolite X, which after making cation exchange and introducing the Pd that catalyzes the reaction inside, it has been possible to obtain an active center with the optimum steric and electronic conditions to carry out the intermolecular regioirregular Mizoroki-Heck reaction between styrenes and iodobenzenes, with good yields and selectivities. On the other hand, a new route for the synthesis of a commercial fragrance, dehydromuscone, has been studied, where a higher overall synthesis yield than the one currently obtained in the industry is obtained. The new synthesis is carried out in less number steps, and a more intense study on the macrocyclization reactive in high concentration has been carried out, in order to evaluate if it is industrially viable. By means of the Mizoroki-Heck reaction studied previously, a study of macrocyclization at high concentration has been carried out where, from some model substrates, the macrocyclization reaction catalyzed by palladium clusters in solution is carried out, to obtain macrocycles with good yields and in a concentration up to 1M. Both computational and kinetic mechanistic studies have also been performed. Finally, the synthesis of two bulky phosphines based on a commercial fragrance and their subsequent coordination with palladium has been studied. Their catalytic scope in challenging organic reactions, such as the telomerization of isoprene, and the Buchwald-Hartwig and Suzuki cross-coupling reactions of chloroderivatives, have been carried out, verifying the catalytic capacity of the complexes formed with our phosphines and palladium. / Garnes Pórtoles, F. (2023). Nuevas reacciones de acoplamiento cruzado de alquenos terminales altamente regioselectivas y catalizadas por paladio [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/195109

In the area of sustainable energy, a major focus has been to design robust electrocatalysts that can be used for the electrolysis of water to produce H2 with a sustainable energy source such as solar. Sustainable H2 generation would potentially be a prelude to the adoption of a hydrogen economy, allowing the phasing out of fossil fuels as a primary fuel source. Toward this end, there is a global research effort to develop electrocatalysts that would facilitate the kinetics of the two half-reactions that make up the water-splitting process: the anodic oxygen evolution reaction (OER) and the cathodic hydrogen evolution reaction (HER). A challenge is to develop active electrocatalysts that are largely composed of earth-abundant elements and show catalytic stability during water splitting at low pH, where the scientific community feels that commercial electrolysis will operate most efficiently. Currently, iridium oxide (IrO2) is being looked at for low pH water splitting because of its stability at low pH, but its relative scarcity (e.g., it is a precious metal) may well make it an unacceptable choice in the long run.In this dissertation, we focus on understanding the scientific issues that will allow the development of earth-abundant catalysts that contain a loading of Ir that is low as possible, while maintaining suitable activity and stability. We began by synthesizing a series of Ir-based OER electrocatalysts by incorporating varying amounts of Ir into 2D layered MnO2 (birnessite, nominally δ-MnO2) and 3D MnO2 (pyrolusite, β-MnO2) phases. The Ir-incorporated δ-MnO2 (Ir/δ-MnO2) electrocatalysts with 16-22 wt% Ir were synthesized by a wet chemical method using a ligating agent, such that Ir was present on the surface and partially intercalated into the interlayer of δ-MnO2. Ir-incorporated β-MnO2 (Ir/β-MnO2) was prepared for the first time via a thermally induced phase transition of Ir/δ-MnO2. This phase transition of δ-MnO2 to β-MnO2 was facilitated by the presence of Ir in the structure, as both Ir in IrO2 and Mn in β-MnO2 could adopt the more thermodynamically stable rutile structure. Extended X-ray absorption fine structure (EXAFS) of Ir/β-MnO2 showed that the catalyst consisted of Ir substituted into the crystalline β-MnO2 lattice, additionally, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and scanning electron microscopy (SEM) imaging revealed micron-sized particles with non-uniform distribution of Ir in the MnO2. In 0.5 M H2SO4 electrolyte, 22 wt% Ir/β-MnO2 (60 〖μg〗_Ir cm_geo^(-2)) resulted in the most active catalyst with an η@10 (overpotential at 10 mA cm_geo^(-2)) of 337 mV and stability of 6 h. This electrocatalyst outperformed a commercial IrO2 on a per Ir mass basis. EXAFS, HAADF-STEM and X-ray absorption near edge structure (XANES) showed that 22 wt% Ir/β-MnO2 had a strained structure containing ~41% Mn3+, an OER active species, along with a modified Ir bonding due to the presence of Ir-O-Ir and Ir-O-Mn. Density functional theory (DFT) computation has demonstrated that this modified bonding environment in Ir/β-MnO2 has contributed to enhancing the thermodynamic stability of the structure. Furthermore, the literature suggests that the presence of Ir-O-Mn bond can favorably tune the d-orbital energy of Ir, enabling superior performance in the Ir/β-MnO2 compared to IrO2. The thesis research also included the investigation of the activity and stability of Ir/β-MnO2 that was synthesized via a novel strategy. The resulting material maintained a homogeneous distribution of Ir in the MnO2 lattice and exhibited excellent OER activity and stability. A surfactant-assisted (SA) synthesis method was carried out to achieve uniform doping of 22-28 wt.% Ir in 3D MnO2 (ramsdellite, R-MnO2). Upon annealing, Ir/R-MnO2 transformed to Ir/β-MnO2 (SA), composed of nano-sized particles. Electrochemical studies in 0.5 M H2SO4 showed that, Ir/β-MnO2 (SA) with 75.6 〖µg〗_Ir cm_geo^(-2) exhibited an η of 327 mV and exceptional stability (up to 50 h). At similar Ir mass loadings, the Ir/β-MnO2 (SA) outperformed Ir/R-MnO2 (SA) and commercial IrO2. This enhanced activity and stability was attributed to a thermodynamically stable structure composed of uniform distribution of Ir (Ir-O-Mn) in the MnO2 lattice. Overall, the research results presented in this dissertation contributed towards designing a novel class of Ir-MnO2 catalysts, which potentially will point the scientific community in the right direction for designing future noble metal-incorporated earth-abundant metal oxides for electrocatalytic energy conversion reactions. / Chemistry

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