In this study the performance of pure, very fine iron (III) oxide powder was investigated as catalyst for the decomposition of sulphur trioxide into sulphur dioxide and oxygen. This highly endothermic reaction requires a catalyst to lower the reaction temperature. This reaction forms part of the HyS (Hybrid Sulphur) cycle, a proposed thermochemical process for the industrial scale production of hydrogen and oxygen from water. The study aimed at obtaining reaction kinetics for this reaction employing pure, unsupported iron (III) oxide as catalyst as a cheaper alternative compared to supported iron catalysts. It was found that the SO3 conversion was carried out in the absence of diffusion limitations and that the reverse reaction did not play a significant role. By assuming plug flow conditions in the reactor and 1st order kinetics, the kinetic parameters of the reaction were obtained. These parameters that form part of the Arrhenius law in describing the reaction rate constant, were determined to be 118(±23) kj / mol for the activation energy ( Ea ), and a value of 3(±0.5) x 108hr-1 was obtained for the Arrhenius frequency factor ( A ). Both values correspond to literature, although in general larger activation energies were published for iron (III) oxide derived supported catalysts. A comparison of the performance of the pure, unsupported iron (III) oxide catalyst with other iron (III) oxide derived supported catalysts (or pellets) has shown that the pure iron (III) oxide catalyst exhibit similar activities. Avoiding expensive catalyst preparation will be an initial step in the direction of developing a cost effective catalyst for the decomposition of sulphur trioxide. It is, however, recommended to investigate different particle sizes as well as purity levels of the unsupported iron (III) oxide to find an optimum cost to performance ratio, as the degree of fineness and the degree of purity will largely influence the final catalyst cost. A qualitative investigation with various reaction product species as well as water in the reactor feed was conducted to assess the influence of these species on the reaction rate. The addition of these species seems to have a larger influence on the reaction rate at low reaction temperatures around 700°C than at higher reaction temperatures (i.e. 750°C and 825°C). This can be attributed to adsorption rates of such species that reduce at higher temperatures. Observations at higher reaction temperatures also suggest that the reaction is of a first-order nature. / MIng (Chemical Engineering), North-West University, Potchefstroom Campus, 2014

In this study the performance of pure, very fine iron (III) oxide powder was investigated as catalyst for the decomposition of sulphur trioxide into sulphur dioxide and oxygen. This highly endothermic reaction requires a catalyst to lower the reaction temperature. This reaction forms part of the HyS (Hybrid Sulphur) cycle, a proposed thermochemical process for the industrial scale production of hydrogen and oxygen from water. The study aimed at obtaining reaction kinetics for this reaction employing pure, unsupported iron (III) oxide as catalyst as a cheaper alternative compared to supported iron catalysts. It was found that the SO3 conversion was carried out in the absence of diffusion limitations and that the reverse reaction did not play a significant role. By assuming plug flow conditions in the reactor and 1st order kinetics, the kinetic parameters of the reaction were obtained. These parameters that form part of the Arrhenius law in describing the reaction rate constant, were determined to be 118(±23) kj / mol for the activation energy ( Ea ), and a value of 3(±0.5) x 108hr-1 was obtained for the Arrhenius frequency factor ( A ). Both values correspond to literature, although in general larger activation energies were published for iron (III) oxide derived supported catalysts. A comparison of the performance of the pure, unsupported iron (III) oxide catalyst with other iron (III) oxide derived supported catalysts (or pellets) has shown that the pure iron (III) oxide catalyst exhibit similar activities. Avoiding expensive catalyst preparation will be an initial step in the direction of developing a cost effective catalyst for the decomposition of sulphur trioxide. It is, however, recommended to investigate different particle sizes as well as purity levels of the unsupported iron (III) oxide to find an optimum cost to performance ratio, as the degree of fineness and the degree of purity will largely influence the final catalyst cost. A qualitative investigation with various reaction product species as well as water in the reactor feed was conducted to assess the influence of these species on the reaction rate. The addition of these species seems to have a larger influence on the reaction rate at low reaction temperatures around 700°C than at higher reaction temperatures (i.e. 750°C and 825°C). This can be attributed to adsorption rates of such species that reduce at higher temperatures. Observations at higher reaction temperatures also suggest that the reaction is of a first-order nature. / MIng (Chemical Engineering), North-West University, Potchefstroom Campus, 2014

Carbon dioxide reforming, or drying reforming, of methane can now be used in new applications such as landfill gas utilization where CO and CH need to be converted to a mixture of CO and H, called synthesis gas or syn-gas. A novel Ni-Co/AlMgO bimetallic powder catalyst was developed in previous research for dry reforming of methane (DRM) process which can eliminate carbon deposition. But it is difficult242x to apply this loose-powder catalyst in industrial scale. The procedure of making spherical Ni-Co/AlMgOx bimetallic catalyst supported on BASF CSS-350 alumina balls (BASF Catalysts LLC) using impregnation method with different impregnation steps and calcination steps is explained in this thesis. For every batch of preparation, the concentration of metal solution was calculated based on different impregnation steps. BET (Brunauer-Emmett-Teller) analysis, compressive strength test, XANES (X-ray Absorption Near-Edge Structure) measurement and ICP-MS (Inductively Coupled Plasma Mass Spectrometry) analysis are conducted to understand the physical and chemical properties of the catalyst. It is found that both impregnation steps and calcination steps have great influence on the performance of the prepared catalyst samples. Among all the catalysts prepared, BF-4-0.25(MgNiCo)-C, which was made by using 4 impregnation-calcination cycles, shows the best activity and stability for 160 h time-on stream (TOS) under the reaction condition of 0.10 g catalyst loading, 750 oC, ambient pressure, GHSV=100,000 ml/gc·h, and CH4/CO2/N2 = 1/1/1. The CH4 conversion started at 66.7% and slowly dropped to 52.8% after 160 hours. I I BF-4-0.25(MgNiCo)-C spherical catalyst shows lower reaction rate compared to the loose powder format but shows compatible or higher activity to other two reported catalysts in similar compositions. Most importantly, it is a shaped catalyst ready for industrial use.

In order to fulfil the requirements in the EURO VI standard, regulating emissions from heavy duty vehicles, the exhaust aftertreatment system needs to maintain its efficiency for at least seven years or 700 000 km. In diesel applications the diesel oxidation catalyst (DOC) is located closest to the engine and is thus the most vulnerable to poisoning contaminants, such as phosphorus originating from fuel and oil additives, which deactivates the catalyst. An idea to reduce the impact from phosphorus impurities (recently patented by Scania CV) is to place a low-cost sacrificial substrate, consisting of one or more pillared clay mineral (PILC) with high affinity for phosphorus, upstream the aftertreatment system in order to protect and thus increase the lifetime of the catalytic components which contain platinum group metals. In this work one commercially available and four custom made PILCs, comprising of two conventional type PILCs and two of the type porous clay heterostructures (PCH), were evaluated. The PILCs were exposed to a phosphorus-containing gaseous mixture using a lab-scale experimental setup in order to determine their phosphorus sorption potential. The PILC materials exhibit potential to function as sacrificial substrates for phosphorus in the intended application. It was indicated to be a correlation between increasing iron content (wt%) and increasing phosphorus sorption capability. The most promising material was the custom made Al,Fe-pillared saponite, which was up to twice as effective in trapping phosphorus as the DOC. The commercial sample, the Al-pillared montmorillonite, was only about as efficient as the DOC.

Since the tragedy of the drug Thalidomide® in the late 1950 to early 1960’s, chirality has been recognized as an important aspect that must be controlled in the drug development process in the pharmaceutical industry. Since then, there has been a considerable movement towards single enantiomer drugs. This demand has presented many challenges for the synthetic organic chemist. Chiral catalysts offer one solution to this problem, as they afford the unique ability to preferentially synthesize one enantiomer. Unfortunately, the design of new chiral catalysts is often empirical, with luck and trial and error necessary due to factors that govern enantioselectivity. Therefore, it would be highly beneficial to develop a method that is capable of screening multiple chiral catalysts early in the catalyst development cycle. Using a modified ion-trap mass spectrometer, the chiral environment of various chiral catalysts may be examined, free from solvent and ion-pairing affects. Thus, the catalyst’s inherent asymmetric environment (enantioselectivity) may be probed using simple chiral molecules, including alcohols, ethers, and epoxides of various steric demands. Using these probes, various C2-symmetric bis-oxazolines and di-imines catalysts were examined. Use of the binaphthyl-based diamine, BINAM, condensed with various 3,5-disubstituted benzaldehydes, provided selectivity close to the privileged catalyst, bis-oxazoline. In general, the chiral probes 1-phenyl-2-propanol, 1-mehtoxyethylbenzene, and styrene oxide offer the best look at the catalyst’s enantioselectivity potential. With the use of the ion-trap mass spectrometer as a mass filter, the purity of the catalyst is not paramount, thus, multiple catalysts may be screened simultaneously, with the constraint that the catalysts must be of different m/z. This thesis presents results found during the exploration of various C2 and C1-symmetric chiral catalysts, in the development of the new chiral screening method utilizing various chiral probes.

Ce travail de thèse s'inscrit dans le cadre de la valorisation du glycérol par polycondensation catalytique. L'objectif est l'obtention de nouveaux catalyseurs basiques hétérogènes actifs et sélectifs pour effectuer la polycondensation directe du glycérol en polymères contenant plus de 5 unités monomères, tout en évitant les sous-produits toxiques (acroléine) et les polymères cycliques. Des précurseurs de catalyseurs associant le lanthane et les différents cations alcalino-terreux ont été obtenus par co-précipitation conventionnelle ou par une voie originale utilisant des ionogels bi-cationiques d'alginate. L'influence de la méthode de préparation, de la température d'activation, de la nature et du contenu en cations alcalino-terreux sur les propriétés physico-chimiques (composition, nature des phases, surfaces spécifiques) et la basicité des catalyseurs a été étudiée. Elles ont été reliées à l'activité et la sélectivité des produits obtenus dans la réaction de polycondensation du glycérol effectuée à 533 K en réacteur batch. / This PhD work deals with the valorization of glycerol by catalytic polycondensation. The main objective is to obtain new heterogeneous basic catalysts, active and selective, able to perform the direct polycondensation of glycerol into polymers containing more than 5 monomer units, avoiding toxic by-products (acrolein) and cyclic polymers. Catalyst precursors involving lanthanum and the various alkaline earth metal cations have been obtained by conventional co-precipitation or by an original route using bi-cationic ionogels of alginate. The influence of the preparation method, the activation temperature, the nature and the content of alkaline earth cations on the physico-chemical properties (composition, nature of the phases, specific surface area) and the basicity of the catalysts was studied. They were related to the activity and selectivity of the products obtained in the polycondensation reaction of glycerol performed at 533 K in batch reactor.

A proposta deste trabalho consistiu em realizar o estudo experimental e matemático do processo de sulfonação de resinas estirênicas reticuladas com etileno-glicol dimetacrilato (PS-EGDMA) e trietileno-glicol dimetacrilato (PS-TEGDMA). O processo de sulfonação de resinas estirênicas é uma das modificações químicas mais utilizadas na indústria e permite conferir características como seletividade às resinas, favorecendo seu uso em diversos processos. Foi utilizado um planejamento de Taguchi L9 com os fatores: fração monomérica, fração de agentes reticulantes e fração de solventes inertes (tolueno e heptano), referentes ao processo de polimerização. As resinas produzidas foram utilizadas na sulfonação, na qual a temperatura foi variada para determinar o ponto ótimo em termos de capacidade de troca iônica e variação de massa. Por meio de balanços de massa e fazendo o uso do modelo do núcleo não reagido foi feita a modelagem matemática do processo. Os resultados obtidos mostram que as resinas reticuladas com etileno-glicol dimetacrilato (EGDMA) e trietileno-glicol dimetcrilato (TGDMA) apresentam boa capacidade de troca iônica (CTI) quando comparadas às resinas comerciais de estireno-divinilbenzeno (S-DVB), como, por exemplo, a Amberlyst®. As partículas sulfonadas de PS-EGDMA apresentaram CTI de 3,988 meq/g com ganho de massa de 30% enquanto as de PS-TEGDMA apresentaram capacidade de 3,477meq/g com ganho de massa de 47% no ponto ótimo tendo sido produzidas com temperaturas de sulfonação de 57,5ºC e 65ºC respectivamente. O modelo desenvolvido apresentou bom ajuste no intervalo entre o início da reação e o ponto máximo de capacidade de troca iônica, sendo capaz de prever as constantes cinéticas e de difusão da reação. Além disso, as partículas produzidas foram testadas na catálise heterogênea e conversões acima de 78% foram obtidas mostrando-se um eficiente catalisador. / The purpose of this work was to carry out the experimental and mathematical study of the sulfonation process of styrenic resins cross-linked with ethylene glycol dimethacrylate (EGDMA) and triethylene glycol dimethacrylate (TEGDMA). The sulfonation process of styrenic resins is very used in industry and allows particles to achieve characteristics like selectivity, favoring its use in several processes. It was used Taguchi L9 experimental design with the following factors: monomer molar fraction, fraction of crosslinking agents and fraction of inert solvents (toluene and heptane), referring to the polymerization process. The resins produced were used in the sulfonation process, in which the temperature was varied to determine the optimum point in terms of ion exchange capacity and mass variation. Mass balances and the unreacted core model were in order to develop the mathematical model. The results showed that PS-EGDMA and PS-TGDMA crosslinked resins exhibit good ion exchange capacity when compared to styrene-divinylbenzene (S-DVB) commercial resins, such as Amberlyst®. The sulfonated PS-EGDMA particles showed ion exchange capacity of 3,988 meq/g with a mass gain of 30% while those of PS-TEGDMA presented a capacity of 3,477meq/g with mass gain of 47% at the optimum point and were produced with sulfonation temperatures of 55.7ºC and 65ºC respectively. The developed mathematical model showed a good fit in the interval between the beginning of the reaction and the maximum point of ion exchange capacity, being able to predict the kinetic and diffusion constants of the reaction. In addition, the produced particles were tested in the heterogeneous catalysis and conversions above 78% were obtained proving an efficient catalyst.

After reaching its light-off temperature, the catalytic aftertreatment system plays a major part in maintaining emissions at low levels for vehicles equipped with combustion engines. In this thesis, modelling of the exhaust gas temperature is investigated along with optimal control strategy for variable ignition and exhaust valve opening angles for optimal catalytic converter heating. Models for exhaust gas temperature and mass flow are presented and validated against measurement data. According to the model validation, the proposed models capture variations in ignition and exhaust valve opening angles well. Optimal control strategy for the ignition and exhaust valve opening angles to heat the catalytic converter to a predetermined temperature in the most fuel and time optimal ways are investigated by implementation of the validated models. Optimal control analysis indicates that with open wastegate, the heating time for the catalytic converter can be reduced by up to 16.4 % and the accumulated fuel to reach the desired temperature can be reduced by up to 4.6 %, compared to the case with ignition and exhaust valve opening angles fixed at nominal values. With closed wastegate the corresponding figures are 16.4 % and 4.7 %. By also including control of the variable λ-value, the heating time can be further reduced by up to 19.8 %, and the accumulated fuel consumption by up to 9.5 % with open wastegate. With closed wastegate the corresponding figures are 20.1 % decrease in heating time, and 9.8 % decrease in accumulated fuel consumption.

Thesis advisor: Dunwei Wang / Non-aqueous Li-O2 batteries promise the highest theoretical specific energy among all rechargeable batteries. It is the only candidate that can be comparable with the internal combustion engine in terms of gravimetric energy density. This makes Li-O2 batteries preferable in the application of electric vehicles or drones. However, the materialization of this technology has been hindered by the poor cycling performance. The major reason for the degradation of the battery at the current research stage has been identified as the decomposition of the electrolyte and the cathode. These parasitic reactions will lower the yield of the desired product and induce huge overpotential during the recharge process. By carefully examining the degradation mechanism, we have identified the reactive oxygen species as the culprit that will corrode the cathode and attack the organic solvents. While parallel efforts have been devoted to reduce the reactivity of these species toward electrolyte, the main focus of this thesis is to identify suitable material platforms that can provide optimum performance and stability as cathodes. A bio-inspired wood-derived N-doped carbon is first introduced to demonstrate the benefit of hierarchical pore structures for Li-O2 cathodes. But the instability of the carbon cathode itself limits the lifetime of the battery. To improve the stability of carbon, we further introduce a catalytic active surface coating of FeOx on a three dimensionally ordered mesoporous carbon. The isolation of carbon from the reactive intermediates greatly improves the stability of the cathode. Yet the imperfections of the protection layer on carbon calls for a stable substrate that can replace carbon. TiSi2 is explored as the candidate. With the decoration of Pd catalysts, the Pd/TiSi2 cathode can provide extraordinary stability toward reactive oxygen species. But this composite cathode suffers from the detachment of the Pd catalyst. A Co3O4 surface layer is further introduced to enhance the adhesion of the catalyst, which doubles the lifetime of the cathode. To achieve a fully stable cathode, Ru catalyst with stronger adhesion on TiSi2 directly is explored and identified to be robust in the operating conditions of Li-O2 batteries. The expedition for stable cathodes in Li-O2 batteries is expected to provide a clean material platform. This platform can simplify the study in evaluating the effectiveness of catalysts, the reaction mechanism at the cathode and the stability of the electrolyte. Toward the end of this thesis, an exploration is made to enable rechargeable Mg metal battery with a conversion Br2 cathode. This new system can avoid the dendritic growth of Li metal by the adoption of Mg as the anode and can promise better cathode kinetics by forming a soluble discharge product. / Thesis (PhD) — Boston College, 2017. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Thesis advisor: Lawrence T. Scott / The Scott lab is interested in the functionalization of corannulene as a building block for large polycyclic aromatic hydrocarbons and carbon nanotube end-cap precursors. Toward that end, a new approach to the direct five-fold borylation of corannulene with iridium (I) catalysts via C-H activation has been explored. It has been discovered that the addition of catalytic amounts of base to the reaction mixture promotes the formation of symmetrical penta-borylated corannulene in a good yield on a sizable scale. All byproducts can be easily removed with iterative methanol washes. The present work also provides proof of the reversibility of the direct borylation reaction under the conditions used. Furthermore, modified Suzuki-Miyaura conditions have been employed to synthesize pentakis(2,6-dichlorophenyl)corannulene, a precursor for a [5,5] carbon nanotube end-cap. The reported reactions provide good yields and are scalable. / Thesis (MS) — Boston College, 2011. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.