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 171 for “"High selectivity"”.
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Inter- and intramolecular (4+2) cycloaddition reactions and tandem inter- and intramolecular (4+2)/intramolecular (3+2)cycloaddition reactions of nitroalkenes
… were found to proceed with extremely high selectivity. It was found that E-nitroalkenes can be prepared from aldehydes using acetylation/dehydroacetylation method.
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Lewis base catalyzed enantioselective oxysulfenylation of alkenes
… mono-, di- and trisubstituted alkenes with high selectivity to form enantioenriched thiiranium ions. Stereospecific and site-selective capture of the thiiranium ions furnish vicinally functionalized thioethers. The nucleophile scope of the reaction encompasses alcohols, carboxylic acids and …
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The nickel-catalyzed Mizoroki-Heck reaction : high regioselectivity in Olefin migratory insertion and photoredox-enabled indoline formation
… formula and color illustrations ...] Achieving high selectivity in the Heck reaction of electronically unbiased alkenes has been a longstanding challenge. Using a nickel-catalyzed cationic Heck reaction, we were able to achieve excellent selectivity for branched products (>/=19:1 in all cases) …
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The stability of phospholipid and biomimetic polymer vesicles
… exceeding commercial RO membranes and high selectivity. These properties make biomimetic materials promising for RO, but investigation of their long-term chemical and physical stability under water treatment conditions is needed to assess their feasibility for use in desalination …
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Aromatization of n-hexane by platinum containing molecular sieves and distribution and motion of organic guest molecules in zeolites
… and chemical composition on activity and selectivity. High selectivity to benzene over most of the zeolite samples demonstrates that support acidity/basicity and microstructure do not contribute directly to the aromatization selectivity over Pt catalysts. A clear trend of increasing …
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Intramolecular (4+2); and tandem intermolecular (4+2);/intramolecular (3+2); cycloaddition of nitroalkenes with achiral and chiral dienophiles
… to form fused ring nitronates with extremely high selectivity. The ring fusion between the carbocycles was dependent on the ring size of the dienophile. However, cycloaddition to afford spiro ring nitronates were unsuccessful.
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Molecular dynamics simulation of nanoporous graphene for selective gas separation
… graphene membranes are expected to yield high selectivity through molecular size exclusion effects, while achieving high permeability due to the very small thickness of graphene. In this thesis, we model the separation of gas components from a mixture using a graphene sheet with engineered …
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In Vitro Selection of Highly Efficient DNA Enzymes as RNA Nucleases and Metal Biosensors
… application in sensing Pb 2+ ions. Combining the high selectivity of 17E towards Pb2+ and the high sensitivity of fluorescence detection, 17E can measure the presence of Pb2+ ions over a concentration range of three orders of magnitude, with a detection limit as low as 10 nM. This system …
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Part I. Isoindolin-1-One Receptors for CG Base Pairs in a DNA Triple Helix. Part II. Cross-Linked Dendrimer Hosts Containing Reporter Groups for Amine Guests
… amine and alcohol guests indicated that it has high selectivity for guests most similar to its original template. However, control studies indicated that this selectivity is due to differing reactivities of guests. Dendrimers containing the core reporter group are a significant expansion in the …
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The reductive animation of ethanol using supported metal catalysts
… reductive amination of ethanol using ammonia. High selectivity to ethylamine product was obtained between reaction temperatures of 140 and 200°C, between ammonia to ethanol molar ratios ranging from 1 to 4 and between hydrogen to ethanol molar ratios ranging from 2 to 5. Depending on the …
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Supporting Well-Defined Platinum Group Metals in Metal-Organic Frameworks for Heterogeneous Catalysis
… many chemical industrial processes which require highly selective transformations, homogeneous catalysts are paramount. The effectiveness of molecular organometallic catalysts in particular can be largely attributed to the precise tools available for synthesis and characterization of the ligands …
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Spatially Resolved Species and Temperature Profiles in the Oxidative Dehydrogenation of Ethane on Mono and Bimetallic Catalysts at Short Contact Times
… quite different product distributions; Rh was highly selective to syngas formation (~80%), whereas Pt produced high selectivity to non-equilibrium C2H4 (~55%). Spatially profiles show that Rh oxidizes feed C2H6 rapidly in the first 3mm of the catalyst to produce H2O, CO and H2 with >99% O2 …
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Development of bimetallic Pd-Zn catalysts for methanol steam reforming: hydrogen production for fuel cells
… i.e. it is obtained sulphur-free, has a high H to C ratio and therefore produces a H₂-rich reformate, can be reformed at low temperatures (200 - 300°C) and is a liquid at ambient conditions so that it can be easily handled. Typically, Cu-based catalysts are used for steam reforming of …
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A comparison of AB diblock and ABA triblock copolymers of polystyrene and polyferocenylsilane for nanolithography applications
… have at our dispossible etching methods with a high selectivity between these two polymers.
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Fluorine-18-labeled estrogens, progestins and corticosteroids for receptor-based imaging of breast tumors and target areas of the brain
… studies of 1 and 2 in immature female rats show high selectivity for target tissue (T, uterus) vs non-target (NT, muscle and lung), with T/NT ratios being 43 and 17 at one hour after injection for 1 and 2, respectively. The parent estrogen FES has previously been shown to display an intermediate …
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LANTHANUM-BASED MATERIALS FOR NUTRIENT PHOSPHORUS REMOVAL FROM AQUEOUS SOLUTION: OPTIMIZATION, CHARACTERIZATION AND APPLICATION
… was the most effective and efficient with the highest phosphate adsorption capacity. On the other hand, the incorporation of lanthanum into polymeric hydrogel bead and membrane allows the materials to be used in column filtration and membrane filtration, respectively. All synthesized …
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Part I. Stereochemical Studies on the Addition of Allylsilanes to Aldehydes. Part II. Stereochemical Studies on the Addition of Allylmetal Reagents to Acetals
… to determine the mechanism and origin of selectivity of the allylmetal-aldehyde reaction. Initial studies were performed to determine the solution structure of Lewis acid-aldehyde complexes. The intramolecular allylmetal-aldehyde reaction was next studied using three different model …
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IDENTIFICATION AND QUANTIFICATION OF IONIC POLLUTANTS IN ENVIRONMENTAL WATER
… pollutant, i.e. Pb2+. This biosensor showed high selectivity toward Pb2+ ions. The detection strategy would provide an opportunity for ?pollution-free? and on-line detection of metal ions in water. In chapter 4, a highly sensitive two-dimensional ion chromatography (IC) method was …
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Charge-Transfer Complexes for Amine Synthesis
… that the radical reductive amination had high selectivity for primary aminothiazoles over secondary amines, contrasting with existing polar reductive amination techniques.
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Catalytic Transformation of Greenhouse Gases in a Membrane Reactor
… This new membrane, termed Nanosil, provided high selectivity to hydrogen at permeabilities comparable to the support material. Application of this membrane in the combined reactor-separator unit provided higher conversions than that obtained using the Vycor membrane.
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