Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 39 for “"heterogeneous catalyst"”.
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DISINFECTION USING A NOVEL HETEROGENEOUS CATALYST
… work to investigate the potential of a novel catalyst in activating H2O2 so as to reduce the concentration of H2O2 used and the time taken for disinfection. The antimicrobial properties of an iron based novel heterogeneous polyacrylonitrile catalyst (PCat) were examined against Escherichia …
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Gas phase heterogeneous catalyst performance testing in laboratory fixed-bed reactors
… among the key factors of the performance of a catalyst. In the development of catalysts these properties are often screened for a range of materials and formulations. Interpretation of these key performance indicators are prone to various confounding effects. Here, performance testing of solid, …
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A microreactor system for high-pressure, multiphase homogeneous and heterogeneous catalyst measurements under continuous flow
… to reduce the time and cost of developing new catalyst systems. Microreactors enable the study of multiphase catalyst systems at pressures that were previously difficult to attain on the laboratory scale. The reduced length scales, characteristic of microchemical systems, provide additional …
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Probing the Surface of a Heterogeneous Catalyst: Double Resonance of Carbon Monoxide Chemisorbed on Highly Dispersed Platinum
Spin Echo Double Resonance (SEDOR) is observed at 77 K for small Pt particles on which ('13)CO was chemisorbed. The samples are Pt supported on eta-alumina with Pt dispersions (fraction of the atoms that are on the surface) of 26% and 76%. After cleaning, the samples are exposed to CO enriched to …
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Probing the surface of a heterogeneous catalyst: Double resonance of carbon monoxide chemisorbed on highly dispersed platinum
Spin Echo Double Resonance (SEDOR) is observed at 77 K for small Pt particles on which l3CO was chemisorbed. The samples are Pt supported on eta-alumina with Pt dispersions (fraction of the atoms that are on the surface) of 26% and 76%. After cleaning, the samples are exposed to CO enriched to 90% …
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The Surface Reaction Mechanisms of Beta-Diketones on Transition Metal Surfaces Including Applications to Metal Thermal Chemical Vapor Etching and Heterogeneous Catalyst Particle Redispersion
… done on alumina and gamma-alumina supported Pd catalysts in an attempt to alter Pd particle dispersion. Low-temperature redispersion of a sintered 5% Pd/gamma-alumina catalyst was most successful via exposure to oxygen and acetylacetone at ∼560 K for 8 hours. A bimodal distribution of CO …
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Development of Biolubricants from Vegetable Oils for Non-Internal Combustion Engine Applications
… as an oxidizing agent in the presence of a heterogeneous catalyst. The conversion, selectivity, oxirane oxygen content (OOC), and iodine value of the final epoxidized canola oil trimethylolpropane (ECOTMP) ester was 95.2%, 98.62%, 4.12%, and 3.4 mg I2/g, respectively. This work has focused …
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FREE-BASE PORPHYRIN FOR CO2 ACTIVATION
… challenging and only few examples of efficient catalysts have been reported up to now. This work is devoted to the study of porphyrins as organic catalysts of the carbon dioxide cycloaddition both under homogeneous and heterogeneous conditions with the final the goal to improve the …
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Effect of a co-solvent feedstock on the synthesis of biodiesel via heterogeneous catalysis
… to be successful in all areas of study with the heterogeneous catalyst nickel oxide. Microreactors are being used to improve the efficiency of the production of biodiesel. The smaller scale makes it possible to produce biodiesel in seconds compared to what industrial biodiesel production requires …
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Preparation of nano and Angstrom sized cobalt ensembles and their performance in the Fischer-Tropsch synthesis
… in a surface polymerisation reaction over a heterogeneous catalyst to mainly long chain hydrocarbons and water. Although all group VIII metals are reported to show activity in this process, only iron and cobalt are used on an industrial scale due to availability and costs. In order to …
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Production and purification of fatty acid methyl esters from plant oils of different origin
… with a short chain alcohol in the presence of a catalyst. The products of the reaction are fatty acid methyl esters (biodiesel) and glycerol, obtained as two separate phases. However, current reaction efficiency using a homogeneous catalyst, such as sodium hydroxide, has various drawbacks. These …
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Selective ethylene dimerization by a nickel-exchanged metal-organic framework catalyst
… structural template for the development of a heterogeneous catalyst for ethylene dimerization. Ni exchanged CPF-5 (Ni-CPF-5) treated with diethylaluminum chloride had a maximum turnover frequency of 23,000 mole ethylene per mole Ni per hour, and a maximum selectivity for 1-butene of 80% under …
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Synthesis and characterization of poly (butyl vinyl ether) homopolymers and copolymers utilizing the aluminum hydrogen sulfate catalyst system
… through the use of the aluminum hydrogen sulfate catalyst (AHS). In this system, AHS acts as a heterogeneous catalyst in the cationic polymerization of vinyl alkyl ethers. Highly isotactic polymers (greater than 70%) have been prepared and characterized by IH and 13C NMR. DSC characterization of …
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The Nucleation and Growth of Nanoparticles for Heterogeneous Catalysis
… with a support affects their reactivity as a heterogeneous catalyst. As capabilities in both synthesis methods and characterization methods advance, the use of nanoparticles and sub-nanometer species are more commonly used. These small particles introduce new factors that can cause differences …
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Investigation of the activity and selectivity of the MoO3/AI2O3 catalyst and the structural investigation using in-situ raman
… Supported molybdenum on alumina is an active heterogeneous catalyst for the metathesis of olefins. Its activity, as a function of time, passes a maximum. It is known that the activity of molybdenum-based catalyst increases up to monolayer capacity. Catalysts with various Mo-Ioadings were …
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Engineering polymeric hollow fiber membrane reactors for sustainable chemical transformation reactions
… of biomass feedstocks. Immobilization of organocatalysts and metal nanoparticles on continuous-flow microreactors offers an efficient catalytic system that exploits and enhances the advantages of both nanocatalysis and flow chemistry, the so-called flow nanocatalysis approach. Various approaches …
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Catalytic Conversion of Cellulose to Carboxylic Acids through Aqueous Phase Partial Oxidation
… which will react on the surface of the catalyst through oxidation reactions to carboxylic acids with high selectivity. Noble metal loaded metal oxides and metal oxides were tested for their catalytic activity in the process. Gold nanoparticle loading was found to promote a yield of 12% …
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Removal of nitrogen containing hydrocarbons from wastewater by catalytic and non-catalytic hydrothermal oxidation, in sub- and supercritical conditions
… for catalytic experiments, the effect of catalyst metal loading and weight were also investigated. Commercially available Ru/Al\(_2\)O\(_3\) pellets were selected for catalytic study after various catalysts were screened. Results indicated that temperature was the key operating parameter …
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Atomic/molecular layer deposition prepared size-selective catalysts and supported nickel catalysts
<p>"Heterogeneous catalysts are widely used because of their many advantages. In this dissertation, the application of atomic/molecular layer deposition (ALD/MLD) in heterogeneous catalyst synthesis and modification was examined.</p> <p>A novel nanostructured size-selective catalyst was synthesized …
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Synthesis of α, β-Substituted Alkenylphosphonates from α-Phosphonovinyl Triflates: I) Palladium Catalyzed Suzuki-Miyaura Cross-coupling with Aryl Boronic Acids II) Palladium Catalyzed Reduction
… solvents (isopropyl alcohol/H<sub>2</sub>O), a heterogeneous catalyst with a very low mole loading (0.007%), and a benign base. The 1-aryl-1-alkenyl phosphonates were prepared in 72-98% yield after purification. Part II of this thesis describes the Pd-mediated reduction of α-phosphonovinyl …
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