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1
Jongsma, Tjeerd. "Polymer-bound rhodium hydroformylation catalysts." [S.l. : [Groningen : s.n.] ; University of Groningen] [Host], 2008. http://irs.ub.rug.nl/ppn/.
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Lamb, Gareth William. "Phosphine modified rhodium catalysts for the carbonylation of methanol /." St Andrews, 2008. http://hdl.handle.net/10023/574.
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Lamb, Gareth W. "Phosphine modified rhodium catalysts for the carbonylation of methanol." Thesis, University of St Andrews, 2008. http://hdl.handle.net/10023/574.
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The carbonylation of methanol to acetic acid is one of the most important applications in homogeneous catalysis. The first chapter comprises a review on the mechanistic studies into the catalytic cycle of the ‘Monsanto process’ and includes some of the most prominent studies into the use of phosphines in the rhodium-catalysed carbonylation of methanol. The second chapter of this thesis reports on an investigation into the application of rhodium complexes containing several C4 bridged diphosphines, namely BINAP, dppb, dppx and dcpb as catalysts for hydrogen tolerant methanol carbonylation. An investigation into the structure, reactivity and stability of pre-catalysts and catalyst resting states of these complexes has also been carried out. The origin of this hydrogen tolerance is explained based on the differing reactivities of the Rh acetyls with hydrogen gas, and by considering the structure of the complexes. In the third chapter I report on an investigation into how electronic properties and coordination mode affect the elimination of phosphonium salts from rhodium complexes. The stability of a range of monodentate, bidentate and tridentate rhodium-phosphine complexes was tested. I also report on the formation of a novel bidentate complex containing a partially quaternised TRIPHOS ligand and investigate the mechanism of formation using 13CH3I. Strong evidence is also presented supporting a dissociative mechanism as the means of phosphine loss from the rhodium centre. In the final chapters I report an investigation into the stability of rhodium-aminophosphine ligand complexes and into increasing the solubility of potential rhodium pre-catalysts through the use of amine-containing phosphine ligands.
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Schnitzer, Jill. "Liquid phase hydroformylation by zeolite supported rhodium." Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/45732.
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The purpose of this research was to directly compare the behavior of zeolites containing rhodium with that of homogeneous rhodium species as catalysts for liquid phase hydroformylation of 1-hexene in order to study the effects of zeolite immobilization. NaX zeolite was cation exchanged with several rhodium salts and used as hydroformylation catalysts at 50°C and 125°C in the presence of: triphenylphosphine (PPh₃), dimethylphenylphosphine (PMe₂Ph), and the poison for zeolite surface and solution rhodium: triphenylmethylmercaptan (Ph₃CSH). The results of these experiments were compared with those of several homogeneous catalysts under similar conditions.
It was found that previously reported results of intrazeolitic activity with RhNaX at 50°C were probably incorrect, since, the addition of PMe₂Ph, Ph₃CSH, or both, virtually halted all reactivity of RhNax.
The catalytic results at 125°C did not conclusively indicate the location of the active rhodium. Thus, intrazeolitic activity at 125°C may or may not have been observed, and needs further investigation.
Reaction profiles were obtained for several of the catalyst systems, using an automatic sampling system. From these profiles, it was found that the addition of excess PMe₂Ph halted isomerization of 1-hexene to 2-hexenes for the zeolite-supported rhodium, and hindered, but did not stop isomerization for the homogeneous catalysts. Also, as expected, it was observed that the homogeneous catalysts reacted to completion faster than the heterogeneous catalyst.
In addition, the effects of such treatments as preheating in air and precarbonylation of the heterogeneous catalysts were studied. Pretreatments had no effect upon the catalysis. Also, no activity was observed from the heterogeneous catalysts at 125°C unless phosphines were present.
Finally, the hydrogenation of 1-hexene was studied. Heterogeneous and homogeneous rhodium catalysts showed hydrogenation activity which was accompanied by isomerization at 60°C and 125°C.Master of Science
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Ferris, Leigh. "Rhodium carboxylates as catalysts for carbenoid transformations." Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/32620.
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Chapter One reviews the literature, discussing the application of metallocarbenoids in asymmetric synthesis. This introduction is mainly concerned with asymmetric carbon-carbon and carbon-heteroatom bond forming reactions and pays particular attention to the levels of stereoselectivity that have been achieved. Chapter Two discusses the use of novel homochiral rhodium(II) carboxylates to effect asymmetric induction in a range of carbenoid transformations. The preparation of these novel rhodium(II) carboxylates is discussed, together with their application in asymmetric catalysis. The work presented is particularly concerned with the insertion of rhodium carbenoids into the heteroatom-hydrogen bond of alcohols, thiols, amines and silanes to prepare enantiomerically enriched a-substituted esters. Chapter Three discusses the generation of oxygen and sulfur ylides followed by a [2,3] sigmatropic rearrangement to generate enantiomerically enriched esters containing a quaternary chiral centre. Asymmetric cyclopropanations and carbon-hydrogen insertion reactions are also discussed. Chapter Four examines the use of diazo phosphonoacetate in organic synthesis. The work has concentrated on the preparation of N-substituted aminophosphonoacetates, by the insertion reactions of anilines, amides and carbamates. These compounds have then been manipulated to prepare a series of amino esters and peptides.
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Roscioni, Otello Maria. "A computational study of supported rhodium catalysts." Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/191339/.
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In this work, density functional theory (DFT) was used to obtain microscopic structures of heterogeneous catalysts based on rhodium supported on a metal oxide (-Al2O3). Two different methodologies were used. The first methodology uses a periodic model and a plane-wave basis set to solve the Schrödinger equation in the framework of Bloch’s theorem. The optimised structures of RhI(CO)2/ -Al2O3 species obtained at this level of theory have bond lengths in agreement with experimental EXAFS determinations. The weighted linear combination of Rh K-edge XANES spectra computed using the three most dominant structures reproduces well the phase and shape of the oscillations of the experimental XANES spectrum, providing support for the computed structures. The second methodology is based on hybrid quantum mechanical (QM)/molecular mechanical (MM) calculations. Within this scheme the support is described at the MM level of theory while the region of interest, the absorption site where the surface RhI(CO)2 complex lies, is described with a suitable QM approach. These hybrid calculations performed at the PBE/ECP/cc-pVDZ level of theory were used to obtainminimum-energy structures and harmonic stretching frequencies of RhI(CO)2/-Al2O3 species. The computed bond lengths and harmonic stretching frequencies were in good agreement with the experimental evidence and with the results obtained using periodic models
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Rode, Edward James. "Rhodium-zeolite hydroformylation of propylene." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/71252.
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The purpose of this research was to characterize the rhodium exchanged NaX and NaY zeolites as propylene hydroformylation catalysts. Catalytic activity was measured in a differential bed reactor. Flow in situ infrared spectroscopy was used to probe the coordination chemistry of the zeolite modified rhodium carbonyls.
The catalytic activity of rhodium zeolites at atmospheric pressure and between 100-150ºC was measured. The rate of n-butyraldehyde production was approximately 5x10⁻³ moles/g-
Rh hr at 150°C. Regioselectivity was dependent upon pretreatment. Precarbonylation with carbon monoxide, drying with air, and heating with N₂ prior to hydroformylation conditions produced a straight to branched isomer ratio (n/i) of 1.9-2.3. Partial reduction with 10% H₂ in N₂ at 127°C lowered n/i to 1.3. Hydrogenation to propane was 3-10 times faster than the hydroformylation rate at 150°C.
Catalytic activity was sensitive to cation exchange conditions. Rhodium form, pH, temperature, and salt concentration altered catalyst behavior. Only RhCl₃•3H₂O preparations on NaY zeolite produced above 80ºC, a pH above 4, and a salt concentration of 0.1N NaCl were required in order to produce an active hydroformylation catalyst. Ammine complexes did not activate under any circumstances.
It was found that the degree of hydration controlled the formation of rhodium carbonyls. On NaY, the hydrated rhodium zeolite reacted with CO at 120ºC to form Rh₆(CO)₁₆. By drying the zeolite in air at 190ºC, two rhodium dicarbonyls, Rh(CO)₂(Oz)₂-NaY and Rh(CO)₂(Oz)(H₂O)-NaY, were formed. The rhodium carbonyls were reacted with n-hexyl diphenylphosphine to determine rhodium locations. Rh(CO)₂(Oz)₂-NaY was located at the surface while the other two species were located within the zeolite cages. One dicarbonyl species, Rh(CO)₂(Oz)₂-NaX, was observed on NaX. It was determined by reactions with phosphines that this species resides in the zeolite cages.
Reaction intermediates identified by FTIR under hydroformylation conditions suggested that the heterogeneous catalyst proceeds through a mechanism similar to that occurring in solution. Heterogeneous reaction orders also agreed with those reported for homogeneous hydroformylations.
Addition of dimethylphenylphosphine (DMP) to the rhodium zeolites significantly increased regioselectivity. Rates were slightly less than those from the unmodified rhodium carbonyls. However, the phosphine modified rhodium zeolites deactivated within 16 hours. Continuous exposure to DMP decreased the rate of deactivation.Ph. D.
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Solmi, Matilde Valeria. "Synthèse d'acides carboxyliques à partir de substrats oxygénés, de CO2 et de H2." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1287/document.
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Les acides carboxyliques aliphatiques sont utilisés dans de nombreux secteurs industriels et leur importance économique augmente. Ils sont actuellement produits en grande quantité, grâce à des procédés utilisant le C0 qui est principalement non- renouvelable. L'anhydride carbonique est une molécule potentiellement écologique, renouvelable et abondante. Cette thèse décrit l'étude et l'optimisation d'un système catalytique homogène de Rh, utilisé pour produire des acides carboxyliques aliphatiques à partir de substrats oxygénés, C02 et H2. Le système consiste en un précurseur de Rh, un additif à base d'iodure et un ligand PPh3, fonctionnant dans un réacteur discontinu sous une pression de C02 et de H2. Les conditions de réaction ont été optimisées pour chaque classe de substrats étudiés: alcools primaires et secondaires, cétones, aldéhydes et époxydes. 30 molécules différentes ont été converties en acides carboxyliques, conduisant à des rendements jusqu'à 80%. En plus, le système a été étudié avec une approche de « Design of Experiment », ce qui a permis d'obtenir des informations supplémentaires concernant les paramètres étudiés. Le mécanisme de réaction et les espèces catalytiques actives ont été étudiés par différentes manipulations comme des réactions compétitives, des expériences de RMN et l'utilisation de molécules marquées. La réaction est composée de transformations non catalytiques et de deux étapes catalytiques. La réaction se déroule à travers une réaction de reverse Water Gas Shift (rWGSR) transformant le C02 et l'H2 en C0 et H20, qui sont consommés dans l'hydrocarboxylation suivante de l'alcène formé in situ pour livrer l'acide carboxylique. Le système catalytique est similaire aux catalyseurs traditionnels à base du Rh pour les réactions de carbonylation et de Water Gas Shift. Le PPh3 est nécessaire pour fournir des ligands supplémentaires, permettant au catalyseur de fonctionner avec une quantité minimale de ligand toxique de C0. En plus, un système catalytique hétérogène a été étudié pour la même réaction. « Single Atom Catalysts » (SACs) reçoit beaucoup plus d'attention que les solutions catalytiques, car il présente à la fois les avantages des catalyseurs homogènes (sélectivité, haute activité) et des catalyseurs hétérogènes (séparation et recyclage faciles). Des atomes de rhodium simples dispersés sur du graphène dopé avec l'N ont été synthétisés et caractérisés, obtenant des informations concernant la structure chimique et physique du matériau. Finalement, ils ont été testés ainsi que les catalyseurs pour l'activation du C02, la production d'acides carboxyliques, les réactions d'hydrogénation et d'hydrogénolyseAliphatic carboxylic acids are used in many industrial sectors and their importance from an economical point of view is increasing. They are currently produced in large quantities, through processes exploiting the mostly non-renewable C0 as C1 synthon. Carbon dioxide is a potential environmentally friendly, renewable and abundant C1 building block. The aim of this work is to provide a catalytic protocol converting C02, H2 and oxygenated substrates to obtain useful chemicals, like carboxylic acids.To this end a homogeneous catalytic Rh system, used to produce aliphatic carboxylic acids starting from oxygenated substrates, C02 and H2 was investigated and optimized. The system consists of a Rh precursor, iodide additive and PPh3 ligand working in a batch reactor under C02 and H2 pressure. The reaction conditions were optimized for each class of investigated substrates: primary alcohols, secondary alcohols, ketones, aldehydes and epoxides. The reaction scope was investigated and 30 different molecules were converted into carboxylic acids, leading to yields of up to 80%. ln addition, the system was studied using a Design of Experiment approach, obtaining additional information regarding the studied parameters.The reaction mechanism and the catalytically active species were studied, by different experiments like competitive reactions, NMR and labelling experiments. This investigation resulted in a deeper knowledge of the reaction pathway, composed of some non-catalytic transformations and two catalytic steps. The reaction proceeds through a reverse Water Gas Shift Reaction (rWGSR) transforming C02 and H2 into C0 and H20, which are consumed in the following hydrocarboxylation of the in-situ formed alkene to give the final carboxylic acid product. The catalytic system is similar to traditional Rh carbonylation and Water Gas Shift catalysts. The PPh3 is needed to supply additional ligands allowing the catalyst to work in reaction conditions with a minimal amount of toxic C0 ligand. ln addition, a heterogeneous catalytic system was investigated for the same reaction. Single atom catalysts (SACs) are receiving much attention as catalytic solution, since they have both the advantages of homogeneous (selectivity, high activity) and heterogeneous (easy separation and recycling) catalysts. Single Rh atoms dispersed on N-doped graphene were synthesized and characterized, obtaining information regarding the chemical and physical structure of the material. Eventually, they were tested as catalysts for C02 activation, carboxylic acid production, hydrogenation and hydrogenolysis reactions
Aliphatische Carbonsauren werden in vielen industriellen Bereichen verwendet und ihre wirtschaftliche Bedeutung nimmt zu. Sie werden derzeit in gror.en Mengen hergestellt, indem das meistens nicht erneuerbare Kohlenmonoxid als C1-Synthon genutzt wird. Kohlendioxid ist ein potenziell umweltfreundlicher, erneuerbarer und abundanter C1-Baustein. Das Ziel dieser Arbeit ist die Entwicklung eines Protokolls zur katalytischen Umwandlung von C02, H2 und sauerstoffhaltigen Substraten, um nützliche Chemikalien, wie Carbonsauren zu erhalten. Zu diesem Zweck wird ein homogenes Rh-Katalysatorsystems zur Herstellung aliphatischer Carbonsauren aus sauerstoffhaltigen Substraten, C02 und H2 untersucht und optimiert. Das System besteht aus Rh-Prakursor, lodid-Additiv und PPh3 als Ligand, die in einem Batchreaktor unter C02 und H2 eingesetzt werden. Die Reaktionsbedingungen wurden für folgende Substratklassen optimiert: primare Alkohole, sekundare Alkohole, Ketone, Aldehyde und Epoxide. Es wurden insgesamt 30 verschiedene Substrate mit Ausbeuten bis zu 80% zu Carbonsauren umgesetzt. Darüber hinaus wurde das System mit einem ,,Statistische Versuchsplanung"-Ansatz untersucht, um zusatzliche lnformationen zu den untersuchten Parametern zu erhalten. Mechanismus und katalytisch aktive Spezies wurden durch verschiedene Experimente wie Konkurrenzreaktionen, NMR- und Markierungsexperimenten untersucht. Dies erschloss den Reaktionsweg, der aus mehreren nicht-katalytischen Transformationen und zwei katalytischen Schritten besteht. Die Reaktion verlauft durch eine ,,reverse Wassergas-Shift-Reaktion" (rWGSR), die C02 und H2 in C0 und H20 umwandelt. Diese werden wiederum bei der nachfolgenden Hydrocarboxylierung des in-situ gebildeten Alkens unter Bildung der Carbonsaure verbraucht. Das katalytische System ahnelt herkômmlichen Rh-Carbonylierungs- und WGSR-Katalysatoren. PPh3 fungiert als zusatzlicher Ligand, der es dem Katalysator ermôglicht unter den gleichen Reaktionsbedingungen mit minimaler Menge toxischen C0 als Liganden zu arbeiten. Zusatzlich wurde ein heterogenes katalytisches System für die gleiche Reaktion untersucht. ,,Single atom catalysts" (SACs) erhalten gror.e Aufmerksamkeit als neue Katalysatorklasse. Sie kombinieren die Selektivitat und hohe Aktivitat homogener und die einfache Abtrennung und Recycling heterogener Katalysatoren Verschiedene Katalysatoren aus auf N-dotiertem Graphen dispergierten Rh-Atomen, wurden synthetisiert und charakterisiert. Dadurch wurden lnformationen über die chemische und physikalische Struktur des Materials gewonnen und als Katalysatoren für C02-Aktivierung, Carbonsauresythese, Hydrierung und Hydrogenolyse getestet
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Warren, James Patrick. "Catalytic chemistry of the rhodium/ceria system : model catalysts and dispersed catalysts." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627214.
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Buck, Richard Tony. "Rhodium carbenoids in asymmetric synthesis." Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267219.
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Karatzas, Xanthias. "Rhodium diesel-reforming catalysts for fuel cell applications." Doctoral thesis, KTH, Kemisk teknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32647.
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Heavy-duty diesel truck engines are routinely idled at standstill to provide cab heating or air conditioning, and in addition to supply electricity to comfort units such as radio and TV. Idling is an inefficient and unfavorable process resulting in increased fuel consumption, increased emissions, shortened engine life, impaired driver rest and health, and elevated noise. Hydrogen-fueled, polymer-electrolyte fuel-cell auxiliary power unit (PEFC-APU) as a silent external power supply, working independently of the main engine, is proposed as viable solution for better fuel economy and abatement of idling emissions. In a diesel PEFC-APU, the hydrogen storage problem is circumvented as hydrogen can be generated onboard from diesel by using a catalytic reformer. In order to make catalytic diesel PEFC-APU systems viable for commercialization research is still needed. Two key areas are the development of reforming catalyst and reformer design, which both are the scope of this thesis. For diesel-reforming catalysts, low loadings of Rh and RhPt alloys have proven to exhibit excellent reforming and hydrogen selectivity properties. For the development of a stable reforming catalyst, more studies have to be conducted in order to find suitable promoters and support materials to optimize and sustain the long-term performance of the Rh catalyst. The next step will be full-scale tests carried out at realistic operating conditions in order to fully comprehend the overall reforming process and to validate promising Rh catalysts. This thesis can be divided into two parts; the first part addresses the development of catalysts in the form of washcoated cordierite monoliths for autothermal reforming (ATR) of diesel. A variety of catalyst compositions were developed containing Rh or RhPt as active metals, CeO2, La2O3, MgO, Y2O3 as promoters and Al2O3, CeO2-ZrO2, SiO2 and TiO2 as support materials. The catalysts were tested in a bench-scale reactor and characterized by using N2-BET, XRD, H2 chemisorption, H2-TPR, O2-TPO, XPS and TEM analyses. The second part addresses the development and testing of full-scale reformers at various realistic operating conditions using promising Rh catalysts. The thesis shows that a variety of Rh on alumina catalysts was successfully tested for ATR of diesel (Papers I-IV). Also, zone-coating, meaning adding two washcoats on specific parts of the monolith, was found to have beneficial effects on the ATR catalyst performance (Paper II). In addition, RhPt supported on CeO2-ZrO2 was found to be one of the most active and promising catalyst candidates for ATR of diesel. The superior performance may be attributed to higher reducibility of RhiOx species and greater dispersion of Rh and Pt on the support (Paper IV). Finally, two full-scale diesel reformers were successfully developed and proven capable of providing high fuel conversion and hydrogen production from commercial diesel over selected Rh catalysts (Papers II-III, V-VI).QC 20110418
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Newman, Andrew D. "Structure and Reactivity of Rhodium Promoted Heteropolyacid Catalysts." Thesis, University of York, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485130.
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Acetic acid is an industrially important chemical with a worldwide demand in the region of 8 million tonnes p.a, over 80 % of which is currently generated via homogeneous methanol carbonylation using Rh or Ir catalysts and MeIi . Recent workii has shown systems combining rhodium and heteropolyacids (HPAs) to be active in the vapour phase carbonylation of methanol or dimethyl ether without a requirement for iodide, and at much milder conditions than existing technologies. However the catalysts rapidly deactivate, and little is known about the structurereactivity correlations or interaction between Rh, HPA and Si02 support. This work investigates the fundamental molecular properties of supported and rhodium-doped phosphotungstic acid catalysts, encompassmg catalyst preparation, activity and deactivation of both bulk and silica-supported Rh/HPA systems. The goal is to understand the operation and characteristics of these catalysts, and to explain and exploit their surprising activity towards methanol carbonylation at low temperatures and pressures. A range of surface and bulk analysis techniques have been employed both insitu and in the study of fresh and deactivated catalysts. The evolution of heteropolyacid on silica with increasing loading has been studied, correlating acidity and XPS measurements with activity in both a-pinene isomerisation and methanol condensation, Above 6.2 wt% catalysts have equivalent acidity, whilst a monolayer of26-44 wt% was most effective in non-polar reactions. Characterisation of rhodium during thermal treatment in reactive and inert atmospheres has been followed, revealing important insights into the composition and nature of deactivation of Rh/HPA/Si02 catalysts. Monolayer HPA/Si02 with -1 wt% Rh was found to be most effective, with diminishing benefit of increasing rhodium content. After initial deactivation, low conversion was sustained; product distribution and spent catalyst characterisation revealed rhodium reduction and agglomeration to be the cause of deactivation - reactivity in acid-only catalysed reactions was unaffected.
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Richards, D. G. "Synthesis gas conversion to oxygenates using rhodium catalysts." Thesis, Brunel University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381157.
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Desset, Simon L. "New strategies for the rhodium-catalysed aqueous-biphasic hydroformylation of medium chain alkenes." Thesis, University of St Andrews, 2009. http://hdl.handle.net/10023/842.
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Aqueous-biphasic organometallic catalysis is, as illustrated by the industrial hydroformylation of propene and butene, one of the most promising ways to overcome the intrinsic problem of catalyst separation in organometallic catalysis. However, for poorly water-soluble substrates, mass transfer limitations bring the reaction rate below any that could be economically viable, greatly limiting the scope of this elegant technology. We have studied three different strategies to overcome this limitation. We developed additives that speed up the reaction whilst retaining fast phase separation and good metal retention. Evidence suggests that those additives affect the reaction by forming emulsions with poor stability under the reaction conditions These emulsions increase the interfacial surface area but break after settling for a short time. We also developed ligands that allow the catalyst to be reversibly transported between an aqueous and an organic phase upon addition and removal of carbon dioxide. This allows the reaction to be carried out under homogeneous conditions, only limited by intrinsic kinetics, and the catalyst to be separated by aqueous extraction triggered by carbon dioxide. The catalyst can be returned to a fresh organic phase by flushing out the carbon dioxide. By applying this methodology for the hydroformylation of medium chain length alkenes, very high reaction rates were obtained and the catalyst could be recycle three times with excellent retention of activity and low metal leaching. This methodology could also be reversed with the reaction being carried out in an aqueous phase in the presence of carbon dioxide and extracting the catalyst into an organic solvent using nitrogen flushing. Finally, we briefly investigated the use of an oscillatory baffled reactor as a mean for mass transfer improvement for aqueous-biphasic hydroformylation. This new type reactor did not improve the performance of the system under the investigated conditions, but may require less energy input for equivalent agitation and mixing.
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Fung, Dawning Chui Mun. "Syntheses, kinetic and homogeneous hydrogenation studies of ditertiary phosphine rhodium(I) complexes." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28782.
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The original purpose of this work was to investigate the catalytic properties of a series of Rh₂(CO)₄(P-P)₂ complexes (where P-P = ditertiary phosphines of the type PR₂(CH₂)nPR₂, R = alkyl or aryl) for hydroformylation. The preparation of Rh₂(CO)₄(P-P)₂ involves the synthesis of Rh(P-P)₂Cl, followed by reaction with NaBH₄ to give RhH(P-P)₂, which when treated with CO in benzene yields Rh₂(CO)₄(P-P)₂, as reported in the literature.
The dimer, Rh₂(CO)₄(dpp)₂, where dpp = PPh₂(CH₂)₃PPh₂, was prepared and examined for its interaction with H₂, and H₂/CO, in order to test its capabilities for catalytic homogeneous hydroformylation.
The interaction of Rh₂(CO)₄(dpp)₂ (49) with H₂, and the reaction of CO with RhH(dpp)₂ (52) to yield 49, are summarized as follows: [Formula Omitted] All the species shown, except 59, have been detected by ¹H and ³¹P{¹H} NMR spectroscopy. Formation of the monomeric hydride, 50, from 49, occurs at high [dpp]. The reaction of Rh₂(CO)₄(dpp)₂ and 6 equivalents dpp with synthesis gas (H₂ : CO = 1 : 1) gives initially 50 and R₂(CO)₄(dpp)₂ reforms after 30 minutes of interaction. This is consistent with the previous finding of low turnover rate for hydroformylation of 1-hexene using as catalyst the co-ordinatively saturated Rh₂(CO)₄(dpp)₂.
Treatment of 52 in toluene with ~1 atm CO, followed by treatment with ~1
atm H₂, sets up the following equilibria (where dpp* = monodentate dpp): [Formula Omitted] The homogeneous hydrogenation of 1-hexene at 31° C, - 1 atm H₂, catalyzed by "the RhH(dpp)₂/CO/H₂ system" in toluene is ascribed to the formation of an unidentified "RhH" from 50 and/or 51. The H₂-uptake curve displayed an initial ("inductive") period required for the generation of an active species "RhH", a second period of maximum rate, and a final slowing down period. The mechanism suggested for homogeneous hydrogenation of 1-hexene catalyzed by the "RhH(dpp)₂/CO/H₂ system" is presented as follows: [Formula Omitted] The corresponding rate law for the maximum rate, consistent with the kinetic data, is given by: [Formula Omitted] where ["Rh"]t is total concentration of the active "RhH" catalyst. At high [1-hexene],
where k₃[1-hexene] >> k₋₃ + k₄[H₂], the rate law is simplified to:
Rate = k₄[H₂],["RhH"]t
where ["RhH"]t ~ total rhodium concentration in solution.
The values of k₃ and k₄ at 31° C were found to be 0.42 M⁻¹ s⁻¹ and 20 M⁻¹ s⁻¹ respectively.
The Rh(dcpe)₂ ⁺X⁻ complexes (X = CI, BF₄, PF₆; dcpe PCy₂(CH₂)₂PCy₂) were prepared and found to have no reactions with NaBH₄ or LiAlH₄. Consequently, the dcpe carbonyl dimer could not be prepared. The Rh(p = p)₂ ⁺Cl⁻ complex, where p = p = PPh₂C₂H₂PPh₂, was isolated and characterized; its reaction with NaBH₄ was incomplete, partially generating RhH(p=p)₂. Treatment of the mixture with CO gave partially Rh(CO)(p=p)₂ ⁺Cl⁻ and another uncharacterized carbonyl complex.
A single crystal X-ray structure determination of Rh(dcpe)₂ ⁺Cl⁻ showed that the geometry around Rh is distorted square planar. Also, the extremely air-sensitive species [RhCl(dcpe)• solv]n (solv = THF or 0.1 C₆H₆) and RhCl(dcpe)(CH₂Cl₂)•C₆H₆ were isolated. The interaction of Rh(dcpe)₂ ⁺Cl⁻ with small gas molecules was studied in order to test its potential as a catalyst. There is interaction between Rh(dcpe)₂ ⁺Cl⁻ and HCI, Cl₂, and CO, in CH₂C1₂. The reaction with HCI to give cis-RhHCl(dcpe)₂ ⁺Cl⁻ is extremely rapid. The use of stopped-flow kinetics and UV-VIS spectrophotometric techniques at 25° C gave an equilibrium constant of 4.2 x 10⁷ M⁻¹ for the reaction. The forward reaction was first-order in both [Rh(dcpe)₂ ⁺Cl⁻] and [HCI], indicating a concerted oxidative addition reaction. The RhHCl(dcpe)₂⁺ species reacts further with HCI to give RhHCl₂(dcpe) and the diphosphonium salt, dcpe(HCl)₂. The Rh(dcpe)₂ ⁺Cl⁻ complex reacts with Cl₂ to give RhCl₂(dcpe)₂ ⁺Cl⁻, which was also obtained by prolonged treatment of RhHCl(dcpe)₂ ⁺Cl⁻ with CDCl₃ The reaction of Rh(dcpe)₂ ⁺Cl⁻ with CO to give Rh(CO)(dcpe)₂ ⁺Cl⁻ yielded k on and k off values of 2.2 x 10⁻² M⁻¹ s⁻¹ and 5.02 x 10⁻⁴ s⁻¹ respectively at 25° C. The Rh(dcpe)₂ ⁺Cl⁻, complex was inactive as a catalyst for decarbonylation of benzaldehyde, or hydrogenation of 1-hexene.Science, Faculty of
Chemistry, Department of
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Selden, Deborah Anne. "New rhodium(II) catalysts and enantioselective carbonyl ylide cycloadditions." Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418476.
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Long, Philip. "Rhodium-phosphinite catalysts for the ortho-arylation of phenols." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529840.
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Kroner, Anna Barbara. "Effect of ceria and zirconia on nanoparticulate rhodium catalysts." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/67241/.
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Rh metal was implemented as a core component in the so-called three-way automotive exhaust catalyst (TWC) due to its excellent properties such as thermal stability, poison resistance and inert behaviour to react with any support materials. These catalysts are often loaded with small amount of promoter elements such as Ce and Zr that enhance their overall catalytic performances and catalyst lifetime. It is therefore desirable to develop new CeOx-based catalyst with both high redox activity and high thermal resistance. Samples of two surface coverages of rhodium on a non-porous high area alumina been synthesised; at 1.6 Rh and 4 wt % Rh loading. Ceria and zirconia have been deposited on the pre-supported Rh catalysts by the controlled surface reaction between the reduced Rh surface and an organometallic precursors: Zr(acac)4 and Ce(acac)3, with different cerium : zirconium ratios: Ce:Zr;1:0, 1:1, 2:1, 0:1. Ceriated Rh catalysts have been also prepared by a different synthesis method, wherein the ceria was deposited on γ-Al2O3 and subsequently Rh metal was added. A series of Rh catalysts produced has been characterised ex situ by BET surface area measurement, TEM, STEM HAADF, EDX, XPS, and XAFS. The combination of Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), Mass Spectrometry (MS) and Energy Dispersive X-ray Absorption Fine Structure (EDE) techniques in a synchronous, time-resolved manner has been applied to determine the complementary information about structural and kinetic changes of the chemical system throughout CO exposure and two catalytic processes: CO oxidation and the reduction of NO by CO in the temperature range between 298 K to 573 K. It has been shown that advanced characterisation techniques, used in the time-resolved, in situ manner were needed in order to understand the behaviour of these complex catalytic systems under operating conditions. The effects of the catalysts’ composition, temperature and pulsed gas flow on catalyst performance have been effectively mapped by the combined DRIFTS/MS/EDE studies. The synthesis procedure has been found to be crucial to achieve the desired interaction between CeOx and Rh particles. No enhancement of ceriated Rh catalysts was observed when ceria was deposited directly on γ-Al2O3 (method I). The addition of each promoter element by the controlled surface modification procedure (method II) exhibits multiple effects on the catalysts performance. The DRIFTS/XAFS studies have confirmed that CeOx and ZrO2 facilitate the protection of Rh particles against extensive oxidation in atmospheres of air, O2 and CO. Larger Rh core particles of ceriated and zirconiated Rh catalysts have been observed when compared with undoped Rh samples. DRIFTS results indicate that by interaction of CO with Rh particles a significantly larger amount of linear CO species was formed on the ceriated Rh surface than in the non-ceriated Rh catalysts case suggesting the presence of predominant metallic Rh phase for that system. Moreover, only ceria doping was found to improve the catalytic activity of promoted Rh catalysts throughout CO oxidation in the temperature ramp mode under different (O2/CO) gas composition.
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Tan, Nicholas Sheng Loong. "Controlled Polymerisation of Arylacetylenes with Well-Defined Rhodium Catalysts." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/82487.
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This thesis details the synthesis of six new rhodium(I)-vinyl and -aryl complexes and their extensive characterisation using a suite of spectroscopic techniques with a primary emphasis on the evaluation of these complexes as initiators for the stereospecific (controlled) (co)polymerisation of phenylacetylenes and other substituted arylacetylene substrates.
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Gibbard, Jonathan Peter. "Homogeneous catalysis for the selective hydrogenation of nitroalkenes." Thesis, University of Exeter, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248125.
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Desset, Simon L. "New strategies for the rhodium-catalysed aqeous-biphasic hydroformylation of medium chain alkenes /." St Andrews, 2009. http://hdl.handle.net/10023/842.
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Parres, Esclapez Sonia. "N2O descomposition rhodium/ceria catalysts: from principles to practical application." Doctoral thesis, Universidad de Alicante, 2011. http://hdl.handle.net/10045/22715.
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Bicknell, C. R. "The role of rhodium in the Andrussow process." Thesis, Nottingham Trent University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389767.
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Ward, Guy Oliver Fairfax. "The use of catalysts and biocatalysts in asymmetric synthesis." Thesis, University of Exeter, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245929.
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Martins, Tânia Isabel Quintas. "Continuous flow homogeneous catalysis using ionic liquid/supercritical fluid biphasic systems." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/982.
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Ionic liquid/scCO₂ biphasic systems have been studied as a possible solution to the main problems concerning homogeneous catalysis reactions such as, the product/catalyst separation, the catalyst retention in the reaction medium and the use of organic solvents. The hydroformylation of long chain alkenes (1-octene) has been carried out as a continuous flow reaction using [OctMIM]Tf₂N (OctMIM = 1-octyl-3-methylimidazolium, Tf = CF₃SO₂) as the reaction solvent and scCO₂as the mobile phase to extract the products. The performance of the rhodium complexes formed with the ionic ligands [PentMIM][TPPTS] (1-pentyl-3- methylimidazolium tri(m-sulfonyl)triphenylphosphine) and [OctMIM][TPPTS] (1-octyl-3- methylimidazolium tri(m-sulfonyl)triphenylphosphine) is described under different sets of experimental conditions. Continuous flow hydroformylation of 1-octene was also carried out using a SILP (Supported Ionic Liquid Phase) catalyst formed with the TPPTS-based ionic ligands named above. The SILP system described in this work has the peculiarity of introducing the “without gases” approach: syn gas was synthesised in situ by the decomposition of formaldehyde. The performance of both systems is compared in the end. The extension of the continuous flow ionic liquid/scCO₂ biphasic system is shown with the optimisation of the silver-catalysed heterocyclisation of furans. A comparison is carried out with a previously developed and optimised continuous flow heterogeneous system.
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Kent, Mark Alexander. "Cobalt PCP pincer and rhodium diphosphine complexes as methanol homologation catalysts." Thesis, University of Bristol, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566818.
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The first two examples of cobalt phosphine PCP pincer complexes, [Co{2,6- (CH2PPh2-KPhC6H3-K[1}(COh] and [Co{2,6-(CH2PPh2-KPhC6H3-KC1}(PMe3h] have been synthesised from the precursors [CoCl(PMe3)3] and [CO(CH3) (PMe3)4]. Both pincer complexes possess pseudo-trigonal bipyramidal geometry with the coordinating pincer P atoms in equatorial sites and the pincer C atom in an axial site. A route to these pincer complexes has been discovered which involves a rearrangement with loss of PMe3 from the cyclometallated complex [Co{2-(CH2PPh2-KP)-4-(CH2PPh2)C6H3-K[1}(PMe3)3]. The mechanism for this rearrangement has been probed by both kinetic studies and deuterium-labelling studies, which suggests that two mechanisms operate, one of which involves a series of intramolecular C-H oxidative additions and reductive eliminations to effectively 'shuttle' protons around the complex. The other mechanism is suggested to involve a proton source, which may be the solvent, THF. The preparation of some rare examples of cobalt phosphinite PCP pincer complexes based on the diphosphinites 1,3-bis(diphenylphosphinooxy)benzene and 1,3-bis(diphenylphosphinooxy)-4,6-(di-tert-butyl)benzene is also reported. The synthesis of these pincers proceeds via an isolated cobalt(III) pincer complex with hydride, chloride and PMe3 ancillary ligands. The subsequent reduction to cobalt(l) pincer complexes proceeds using NEt3 or LiAlH4 as reducing agents. The new propane-backboned diphosphines 1,3-bis(SH-benzo[b ]phosphindol-S- yl)propane and 1,3-bis(di-2-naphthylphosphino)propane were synthesised. These diphosphines were complexed with [{RhCl(COh}Z] to afford the corresponding dinuclear 12-membered metallacycles [{RhCl(CO)(Il-diphosphine)}2], the latter of which possesses two rotational isomers which involves the exchange of the positions of one Cl and one CO ligand. The diphosphines 1,3-bis(SH- benzo [b] phosphindol-S-yl) propane and o-di phenyl phosphino benzyldi phenyl- phosphine were complexed with [Rh(CODh]BF4 to afford cis-chelating mononuclear Rh(l) complexes. The application of these phosphines and complexes as catalysts for methanol reductive carbonylation and homologation has been investigated. The catalyst involving the tetrahydrochloride salt of 1,3-bis( di-2-pyridylphosphino )propane exhibits methanol reductive carbonylatiori/homologation selectivity superior to the best previously reported literature system. Also, the catalyst involving the diphosphine 1,3-bis(SH-benzo[b ]phosphindol-S-yl)propane exhibits promising stability and selectivity to acetic acid under reductive carbonylation conditions, signalling a potential application as a methanol carbonylation catalyst.
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Petch, Michael Ian. "An investigation of CO/Hâ†2 reactions on promoted rhodium catalysts." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292638.
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Oliver, James Alexander. "The reaction of hydrocarbons over platinum-rhodium and other bimetallic catalysts." Thesis, University of Edinburgh, 1985. http://hdl.handle.net/1842/12728.
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Sheerin, Ephraim A. "Synthesis of Ethanol from High Pressure Syngas over Rhodium-Based Catalysts." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397476742.
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Brown, Rachel Ann. "Environmental impact of platinum, palladium and rhodium in the roadside environment." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271417.
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Kröger, V. (Virpi). "Poisoning of automotive exhaust gas catalyst components:the role of phosphorus in the poisoning phenomena." Doctoral thesis, University of Oulu, 2007. http://urn.fi/urn:isbn:9789514286087.
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Abstract
The aim of this thesis project was to gain new knowledge on the effect of phosphorus on the catalytic activity and characteristics of automotive exhaust gas catalyst components. The simultaneous roles of phosphorus and calcium were also studied.
The first test series of powdery catalyst samples contained Rh and oxide (Test series 1) and the second, Pt and oxide or ZSM-5 (Test series 2). The catalysts were analyzed when fresh and after two ageing and phosphorus poisoning procedures developed in this work. The procedures consisted of adding poison via impregnation in an aqueous solution (for Test series 1) and in the gaseous phase under hydrothermal conditions (for Test series 2). The poison compounds formed and the changes in the washcoat were studied by using physisorption analyses, SEM, TEM, XRD, and FTIR-ATR. The poison content of the samples was determined by ICP-OES and XRF. Laboratory-scale activity measurements were done to investigate the catalytic activity. Thermodynamic calculations were used to obtain information about ageing conditions and phosphorus compounds formed during ageing.
Phosphorus decreased the catalytic activity and the characteristic surface areas of the catalysts. Addition of calcium to a phosphorus-poisoned catalyst was found to have even a regenerating effect on the catalysts' activity. The poisoning methods developed in this study resulted in the same phosphorus compounds as can be found in vehicle-aged catalysts. Phosphorus was identified as cerium, zirconium, aluminium, and titanium phosphates. Phosphorus was detected in zeolites, but phosphorus-containing compounds were not observed. Phosphorus poisoning takes place in the gas phase at high operating temperatures and with high oxygen and water contents. It was also shown that the role of phosphorus poisoning was more pronounced than the role of hydrothermal ageing alone. Phosphorus poisoning mainly affects the oxide components used in this study, not the noble metals.
The results can be utilized in the development of catalytic materials and catalyst compositions that can better tolerate phosphorus poisoning under hydrothermal conditions. The results can also be applied in evaluating the effects of phosphorus on different catalyst compositions and in estimating the age of commercial catalysts.
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Shimizu, Hiroshi. "Development of New Synthetic Reactions Using Rhodium Catalysts and Organoboronic Acid Derivatives." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/152524.
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Pierson, Nicolas. "New chiral rhodium(II) catalysts for asymmetric synthesis with #apha#-diazocarbonyl substrates." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263509.
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Hindle, Kenneth Thomas. "The liquid phase hydrogenation of para-toluidine over silica supported rhodium catalysts." Thesis, University of Glasgow, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439210.
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Neveling, Arno. "Preparation of new rhodium and cobalt complexes as catalysts for hydroformylation studies." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/49777.
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Moorthiyedath, Sajeev. "Surface characterization of Rh-Co, Ru-Co and Pd-Co bimetallic catalysts." Master's thesis, Mississippi State : Mississippi State University, 2003. http://library.msstate.edu/etd/show.asp?etd=etd-07032003-131340.
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Tian, Jianhua. "Syntheses and applications of soluble polyisobutylene (PIB)-supported transition metal catalysts." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3129.
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Gong, Zhenxin. "Continuous flow homogeneous hydroformylation of 1-octene over supported ionic liquid phase rhodium catalysts using supercritical CO₂." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/1877.
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The hydroformylation of 1-octene with supported ionic liquid phase catalyst was demonstrated when using a system involving the substrate, reacting gases and products in CO₂ and N₂ flow over a fixed bed supported ionic liquid phase catalyst (silica gel and carbon aerogels as solid support respectively) at different system pressures. Yields, reaction rates, selectivities and rhodium leaching were all monitored. A pressure of CO₂ flow just below the critical point of the flowing mixture (106 bar at 100 °C if no 1-octene has been converted) was the best condition for the hydroformylation. It gave the highest acitivity (conversion to aldehyde up to 70 %), fastest reaction (TOF up to 575.3 h⁻¹) and best stable selectivity ( l:b ratio reaching 3.37 ). The utilization of scCO₂ as reaction media leads to remarkable stability of the catalyst. The supercritical or near critical (expanded liquid) system completely overcame the progressive decrease in activity of catalyst at 50, 75 bar with liquid phase transport and also showed much better results than when using other gas flows such as N₂ flow at 100 bar. In the high pressure scCO₂ phase, the concentration of 1-octene at the catalyst bed was reduced so that the conversion to aldehyde was reduced. The pore size and surface groups of the solid support should be suitable for the SILP catalyst consisting of metal complex, excess ligand and ionic liquid. Using microporous carbon aerogels as the supports, whether activated or not, gave disappointing results.
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Rifat, Adem. "Exo-closo carborane complexes of rhodium and iridium : synthesis and evaluation as hydrogenation catalysts." Thesis, University of Bath, 2003. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425661.
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Chan, Ka Wang. "Synthesis and reactivity of iridium, rhodium and ruthenium alkyl complexes containing 2,2'-bipyridine /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202008%20CHANK.
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Fjellander, Ester. "Self-adaptable catalysts : Importance of flexibility and applications in asymmetric catalysis." Doctoral thesis, KTH, Organisk kemi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12852.
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The topic of this thesis is the design and synthesis of biaryl-based self adaptableligands for asymmetric metal catalysis. The results discussed in papers I-III are covered, together with some unpublished results concerning substrate-adaptable catalysts. A general survey of self-adaptable catalysts is presented first. The second chapter of this thesis starts with a survey of inversion barriers in biphenyl-based ligands and catalysts. Thereafter, the determination of barriers to conformational adaptation in dibenzoazepines and dibenzophosphepines is described. Palladium complexes with a diphosphine ligand or a diamine ligand, as well as the free diamine ligand, were studied. Entropies and enthalpies of activation were determined with variable temperature NMR spectroscopy. The mechanism of conformational change in the metal complexes was elucidated. The third chapter describes the synthesis of semiflexible and rigid phosphinite ligands, as well as their application in rhodium-catalysed asymmetric hydrogenation. Modest enantioselectivities (up to 63% ee) were obtained. The semiflexible ligand was found to behave like the most active rigid diastereomer. The fourth chapter describes the behaviour of amine and phosphoramidite ligands in model complexes relevant to the palladium-catalysed asymmetricallylic alkylation of benchmark substrates. Diphosphoramidite and aminephosphoramiditeligands were designed and synthesised. Pd(olefin) complexesof diamine and diphosphoramidite ligands were studied, and their symmetry determined. It was found that both types of ligands are able to adapt their conformation to the substrate.QC20100630
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Price, David Wilfred. "Directed hydrogenation of sulphoxides and sulphones." Thesis, University of Oxford, 1992. http://ora.ox.ac.uk/objects/uuid:725ef76d-0cc3-4b6c-afa4-ff95f078b6da.
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This thesis describes the synthesis of a number of hydroxy vinylsulphoxides and sulphones by a high pressure modification of the Baylis-Hillman reaction, together with their directed hydrogenation catalysed by rhodium catalysts. A detailed kinetic analysis of a number of the hydrogenation reactions carried out by numerical analysis is also presented. Chapter 1 serves as an introduction to directed hydrogenation and the chemistry of sulphur containing compounds. Chapter 2 details the synthesis of catalysts and substrates used in hydrogenation reactions. The use of high pressures to improve the performance of the Baylis-Hillman reaction is included. Chapter 3 details the products and the selectivity obtained in the hydrogenation of hydroxy vinylsulphoxides and sulphones. The kinetic resolution of 3-phenyl-2-(phenylsulphonyl)- propene-3-ol using a DiPAMP rhodium catalyst is described. Chapter 4 details the numerical analysis of the kinetics of the hydrogenation reactions of a number of hydroxy vinylsulphoxides and sulphones.
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Stratton, Samantha. "The synthesis of rhodium nanoparticles in conventional and alternative media as catalysts for arene hydrogenation." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106477.
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Two systems for rhodium nanoparticle (Rh NP) synthesis were examined. A series of traditional organic ligands, such as triphenylphosphine or bipyridine (bipy), in THF were employed during the reduction of Rh(allyl)3, a "salt-free" metal precursor, using H2(g) as reducer. These ligands, employed in excess, afforded Rh NPs, but failed to produce mono-dispersed samples. The Rh NPs obtained failed to catalyze the arene hydrogenation reaction and resulted in large aggregates under catalytic conditions. To explore other stabilization methods, Rh NPs stabilized by phosphine functionalized ionic liquids (FILs) were prepared in [BDMI]NTf2 (BDMI = 1-butyl-2,3-dimethylimidazolium, NTf2 = bis(trifluoromethanesulfonyl)imide) using H2(g) (4 bars) as a reducer. The Rh(allyl)3 precursor proved to be a better choice than the usual RhCl3 precursor, which could not produce long-lasting, stable particles under catalytic conditions. The synthesized FIL stabilized Rh NPs proved to be active biphasic catalysts for the hydrogenation of toluene, styrene and xylenes under mild conditions (75ºC, 40 bar H2(g), 3h). The impact on activity of the length of the spacer between the phosphine function and the ionic liquid moiety in the FIL was studied. The Rh NPs stabilized by FILs showed higher catalytic activity and recyclability than NPs synthesized in the absence of a stabilizer and more stable than the system employing triphenylphosphine in [BDMI]NTf2 as a stabilizer. The size of the stabilized Rh NPs was measured to be around 2 nm by TEM, while those produced in the absence of a FIL stabilizer formed only aggregates.Deux systèmes pour la synthèse de nanoparticules de rhodium (NPs Rh) ont été examinés. Plusieurs ligands classiques, comme la triphenylphosphine ou la bipyridine (bipy), ont été employés dans le THF pour la réduction de Rh(allyl)3, un précurseur métallique ne générant pas de sel, en utilisant H2(g) comme réducteur. Ces ligands, placés en large excès, ont permis d'accéder à des NPs Rh, mais n'ont pu permettre l'obtention d'échantillons monodisperses de petites particules. Dans tous les cas, les NPs Rh obtenues n'ont pu catalyser la réaction d'hydrogénation des arènes et ont formé de larges aggrégats en conditions catalytiques. Pour étudier d'autres méthodes de stabilisation, des NPs Rh, stabilisées par des liquides ioniques fonctionnalisés avec un groupement phosphine (LIFs), ont été préparées dans le [BDMI]NTf2 (BDMI = 1-butyl-2,3-dimethylimidazlium, NTf2 = bis(trifluoromethanesulfonyl)imide) sous pression d'H2(g) (4 bars) comme réducteur. Le précurseur Rh(allyl)3 s'est révélé être un meilleur choix que le précurseur classique, RhCl3, qui conduit à des particules instables dans le temps, dans les conditions de la catalyse. Ces NPs Rh se sont révélées être actives en catalyse d'hydrogénation du toluène, du styrène et des xylènes en conditions douces (75ºC, 40 bar H2(g), 3h). L'effet sur l'activité de la longueur de l'espaceur entre la phosphine et la fonction imidazolium dans le LIF a été étudié. Les NPs Rh stabilisées par des LIFs se sont avérées les plus actives en catalyse. Leur recyclabilité est supérieure à celle des systèmes sans stabilisants. Elles sont également plus stables que le système avec la triphenylphosphine comme stabilisant dans le [BDMI]NTf2. La taille des NPs Rh a été mesurée à 2nm par TEM, alors que le système sans stabilisation n'a produit que des agrégats.
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Basri, Aida Maryam Binti Haji. "Synthesis of ruthenium and rhodium complexes for their use as anti-cancer agents and catalysts." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/7704/.
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This thesis is concerned with the synthesis and characterisation of a series of functionalised bis-picolinamide ruthenium and rhodium dihalide complexes that have the potential to be developed as anti-cancer agents and catalysts. Their structural characterisations and, anti-cancer and catalytic activities were explored and investigated. There are more than thirty novel bis-picolinamide ruthenium dihalide complexes [RuX2L2] and six bis-picolinamide rhodium dihalide complexes [RhX2L2] (where X is chloride or iodide, and L is the functionalised bidentate picolinamide ligand) synthesised and fully characterised. X-ray crystallography showed the picolinamide ligands are bonded in N,N- and N,O- coordination modes to the metal centre. Three different geometries were seen for the dichloride complexes which were cis-cis-cis, cis-trans-cis and trans-trans-trans, whereas only the trans geometry was seen for the diiodide complexes. UV-Vis solution studies of the Ru complexes have shown no visible changes in the spectra over a range of days and temperature. Powder diffraction of Ru dichloride gave inconclusive data, however Ru diiodide complexes showed evidence of trans structural stability. As Ru(III) complexes are not amendable to study by NMR, Rh analogues were prepared to analyse their structural characterisation. The results have shown that there is a possible mixture of three different isomers within the Rh dichloride complexes, whereas the Rh diiodide only showed trans isomer, confirming that the diiodide complexes both for Ru and Rh are stable in structure conformations. There has been much interest in developing new metal-based anti-cancer complexes since the successful discovery of cisplatin. Ru-based complexes have become one of the most promising groups of complexes, having cytotoxic properties but not significantly affecting normal healthy cells. Bis-picolinamide Ru dihalide complexes were tested against a variety of cancer cell lines to determine the cytotoxicity. It was found that the cytotoxicity increases when changing the halide ligands from dichloride to diiodide, and when the substituents on the phenyl ring of the ligands are meta or para chloro or bromo substituents. Complexes 4.8 and 4.13 are the two most promising anti-cancer complexes, which are potent both under normoxic and hypoxic conditions. Following the cytotoxicity studies, selected complexes were examined for hydrolysis and hydrophobicity. The most cytotoxic Ru dichloride complex hydrolyses more and undergoes the fastest hydrolysis, which is in contrast with Ru diiodide complexes, by which the most cytotoxic complex undergoes the least hydrolysis. There are very few correlations observed between the cytotoxicity and log P values of the Ru dichloride complexes, suggesting that the cell uptake mechanism may not relate to their cytotoxic anti-cancer activities. The ongoing research on catalytic transfer hydrogenation reaction is targeted towards metal catalysts that can favour high activity under mild operating conditions. Several bis-picolinamide Ru and Rh dihalide complexes were studied as catalysts in the reduction of benzaldehyde. The complexes that were selected for the studies have several components that can be used to investigate their structural-activity relationships. In general, the diiodide analogues of the catalysts are more active than the dichloride analogues. In combination of the dihalide ligands with the appropriate functionalised picolinamide ligands can improve their catalytic activities. There is a contrasting activity seen between Ru and Rh catalysts, whereby their catalytic activities are affected by different components of the catalysts. Ru catalyst may be largely affected by the different functionalised picolinamide ligands, whereas Rh catalysts have showed difference in activities when changing the X ligands.
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Eriksson, Sara. "Development of catalysts for natural gas-fired gas turbine combustors." Doctoral thesis, Stockholm : Department of Chemical and Engineering and Technology, School of Chemical Science and Engineering, KTH - Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4239.
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Barroo, Cédric. "Processus non-linéaires au cours de l'hydrogénation du NO2 sur catalyseurs à base de platine et de rhodium." Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209252.
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Le travail de thèse propose d’éclaircir les dynamiques qui régissent les réactions d’hydrogénation du dioxyde d’azote (NO2) se déroulant à la surface de catalyseurs modèles de platine, de rhodium et de leur alliage Pt-Rh. Une meilleure compréhension de la réaction catalytique en conditions réactionnelles permettrait, à terme, un meilleur contrôle de la réaction. De manière similaire, le comportement du catalyseur permettrait d’orienter la synthèse de catalyseurs afin d’en augmenter la sélectivité et/ou activité. La structure de ces catalyseurs ainsi que l’analyse des processus sont effectuées à l’échelle nanométrique grâce à l’utilisation de microscopies à effet de champ :la microscopie ionique à effet de champ (FIM) et la microscopie d’émission d’électrons par effet de champ (FEM). La réaction NO2+H2 étudiée à 390 K sur le platine permet de mettre en évidence la présence de différents domaines réactionnels :dynamique monostable, oscillations périodiques auto-entretenues, oscillations périodiques bimodales, ainsi que des oscillations bruitées. Malgré la présence importante de fluctuations à l’échelle du nanomètre, les traitements de signaux mettent en évidence une importante robustesse qui se traduit par un temps de corrélation qui s’étend sur plusieurs centaines de périodes. Les données donnent matière à la reconstruction de l’attracteur dynamique consistant en un cycle limite. La pression d’hydrogène est le paramètre de contrôle qui est varié de sorte à provoquer l’apparition d’oscillations selon une bifurcation de type homocline dans ce cas-ci. Des mesures à haute-vitesse d’acquisition démontrent que l’ignition des différentes faces réactives s’effectue de manière désynchronisée, et la vitesse de propagation est de l’ordre de ~2 μm/s. Au sein d’une seule face, à l’échelle du nanomètre, des propagations de fronts d’ondes chimiques peuvent également être observées à une vitesse de ~2 μm/s, en accord avec les vitesses analysées lors d’expériences menées à l’échelle du micromètre et du millimètre. Sur base des observations, un mécanisme réactionnel de production d’H2O a été proposé. La réaction sur le rhodium à 450 K engendre également des oscillations périodiques qui diffèrent par une robustesse plus faible et par l’apparition d’un cycle limite selon une bifurcation de Hopf. Des mesures exploratoires à 500 K font ressortir la présence de chaos dans le système. Finalement, l’alliage Pt-Rh utilisé comme catalyseur permet d’obtenir des oscillations à 425 K de période comprise entre celles observées sur les deux métaux purs. L’ensemble des expériences et des résultats obtenus à l’échelle du nanomètre permet pour la première fois de valider la théorie des systèmes dynamiques à une telle échelle.Doctorat en Sciences
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Antonels, Nathan. "Synthesis and characterization of poly(proyleneimine)-based Rhodium(I) Metallodendrimers and their evaluation as Hydroformylation catalysts." Master's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/6295.
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A series of new iminopyridyl- and iminophosphine-functionalized dendritic ligands were synthesized by reacting the commercially available first and second-generation DAB poly(propyleneimine) (PPI) dendrimers with 4-pyridinecarboxaldehyde and 2-(diphenylphosphino)benzaldehyde respectively via a Schiff-base condensation reaction. The ligands were characterized using NMR and IR spectroscopies, elemental analyses and mass spectrometry. Model monomeric analogues of these multimeric ligands were synthesized to aid with interpreting the more complex spectra of the dendritic ligands. The iminopyridyl-functionalized ligands were reacted with [RhCl(COD)]2 to yield a set of new mononuclear and multinuclear rhodium(I) complexes that coordinated selectively to the pyridyl nitrogen in a monodentate coordination mode. The iminophosphine functionalized ligands were reacted with [RhCl(CO)2]2. These reactions yielded a set of new mononuclear and multinuclear iminophosphine rhodium(I) complexes, where the P,N-donor iminophosphine ligands coordinated to the rhodium metal center in a heterobidentate coordination mode to form chelate complexes. The complexes were characterized using NMR and IR spectroscopies, elemental analyses and mass spectrometry. Crystals of the mononuclear iminophosphine rhodium(I) complex were obtained and the molecular structure solved using single crystal X-ray diffraction analysis. Chemical reactivity studies were conducted on the mononuclear and multinuclear iminopyridyl and iminophosphine complexes. The iminopyridyl rhodium(I) complexes were reacted with triphenylphosphine. These reactions yielded similar results to that of the reaction between the iminopyridylfunctionalized ligands and [RhCl(PPh3)3]. Methyl iodide was reacted with the mononuclear and multinuclear iminophosphine rhodium(I) complexes. Reactions of methyl iodide with the mononuclear iminophosphine rhodium(I) complex yielded a mixture of the oxidative addition and the acyl product, where the acyl product results from a subsequent alkyl migration into the metal carbonyl bond after oxidative addition has occurred. Reaction of methyl iodide with the multinuclear metallodendritic iminophosphine rhodium(I) complexes yielded the oxidative addition product exclusively. Reaction products were monitored using IR spectroscopy. Selected mononuclear and multinuclear iminopyridyl and iminophosphine rhodium(I) complexes were evaluated as catalysts in the hydroformylation of 1-octene. The complexes showed moderate hydroformylation rates under mild conditions. The multinuclear metallodendritic rhodium(I) complexes compare favorably to that of the mononuclear rhodium(I) complexes showing slightly enhanced catalytic activity and regioselectivity in certain cases. Hydroformylation results obtained when using these complexes compare well to results obtained when using [Rh(acac)(CO)2] under similar conditions, a rhodium(I) complex commonly used in literature.
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Thu, Hung-yat. "Catalytic C-H bond functionalization reactions catalyzed by rhodium(III) porphyrin, palladium(II) and platinum(II) acetate complexes." View the Table of Contents & Abstract, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38027872.
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Shen, Xiaodong [Verfasser], and Eric [Akademischer Betreuer] Meggers. "Octahedral Chiral-at-Metal Iridium and Rhodium Complexes as Versatile Asymmetric Catalysts / Xiaodong Shen. Betreuer: Eric Meggers." Marburg : Philipps-Universität Marburg, 2016. http://d-nb.info/1102354457/34.
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Eriksson, Sara. "Development of methane oxidation catalysts for different gas turbine combustor concepts." Licentiate thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-311.
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