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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 231 for “"Carbon-carbon"”.
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Carbon-Carbon Bond Formation Via o-Lithiointermediates
… fractional equivalents of TMEDA in hydrocarbon solvents at 60°C, o-lithiation of anisole and dimethylaniline can be effected in >95% yields. The first step in the DoM process involves preparation of solid samples of these o-lithiointermediates. Completing the sequence, the second step …
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1,6-Eliminations with two carbon-carbon cleavages
Made available in DSpace on 2014-12-09T17:35:27Z (GMT). No. of bitstreams: 1 6607728.pdf: 5376218 bytes, checksum: bd508fed35fcb7307a8f53940d48345b (MD5) Previous issue date: 1966
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Selective Borylations of Carbon-Carbon pi-Bonds
… reaction, which is used to generate carbon-carbon bonds under mild conditions. Because of the versatility of organoboron reagents, methods to selectively install boron remains crucial. Boron containing compounds have recently garnered significant interest in the medicinal chemistry …
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Brønsted Acid Catalyzed Carbon-Carbon Bond Forming Reactions
… this research project will unveil new asymmetric carbon carbon bond forming reactions between substrates hitherto unexplored with Brønsted acid catalysis. It has been established that strong Brønsted acids, such as phosphoric acids, are capable of mediating highly selective transformations …
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Thermal stresses in coatings on carbon-carbon composites
… stresses in oxidation protection coatings on carbon-carbon composites. Multilayer coatings with each layer of coating applied at a different temperature, and gradient coatings with continuously varying properties through the thickness of the coating were considered. Particular emphasis was on …
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Micromechanics of crenulated fibers in carbon/carbon composites
… transverse strain and to a temperature change in carbon/carbon composites is examined using the finite element method. Stresses at the interface of both fully bonded and fully disbonded fibers having two crenulation amplitudes and with two fiber volume fractions are presented. In each case, these …
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Multiscale Numerical Modeling and Characterization of Carbon/Carbon Composites
<p>Carbon/carbon composite is a high-performance material with a unique set of physical and thermo-mechanical properties making it irreplaceable for severe environment aerospace applications. Its complex hierarchical microstructure presents materials scientists and engineers with substantial …
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Nucleophilic Carbon-Carbon Bond-Forming Reactions of 2-Methylenetetrahydropyrans
… C6-substituted enol ether substrates.</p> <p>The carbonyl-ene reaction of exocyclic enol ethers provides 2-β hydroxy dihydropyrans in excellent yields at room temperature. This process only requires catalytic levels of zinc chloride, and both activated and non-activated carbonyl-enophiles act as …
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Friction Characteristic Prediction within a Carbon-Carbon Race Clutch
… the effectiveness of clutches, the properties of carbon fibre reinforced carbon (known as carbon-carbon) composites are considered to be superior to any other candidate materials available. The cost of devices made from such materials has precluded their use in “everyday” applications and limited …
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The mechanical properties of tightly woven carbon-carbon composites
<p>The mechanical properties of a tightly woven carbon- carbon composite were investigated. The flexural strength and fracture toughness of these composites were measured as a function of temperature and atmosphere. The average flexural strengths are 147.1 ± 6.4 MPa in air and 144.0 ± 5.9 MPa in …
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NEW TRANSITION METAL CATALYSTS FOR CARBON-CARBON BOND FORMATION
… complexes have been applied to the formation of carbon-carbon bonds both as reagents and catalysts. Ligands and complexes tailored for a particular reaction have facilitated superior yields, catalytic activity, and selectivity. This dissertation focuses on two catalyst systems enabling …
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Development and application of carbon-carbon bond forming methodologies
… An organocatalytic, asymmetric addition of carbon nucleophiles to prochiral aldimines was developed. This transformation capitalizes on the inherent properties of boron to promote a ligand exchange with chiral diols generating a chiral nucleophile in situ. Mechanistic studies were carried …
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Palladium catalyzed carbon-carbon bond formation at carbon-hydrogen bonds
The biaryl core has been identified by medicinal chemists as a privileged structure in pharmaceutical compounds as it is found in 4.3% of all drugs. For over a century, synthetic chemists have sought new methods for their preparation. Breakthroughs in synthetic catalytic methodology over the past …
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Carbon-Carbon Bonds Formed by Lewis Acid Catalysis or Photoactivation
… is described the synthesis of tertiary and all-carbon quaternary centers from propargylic alcohols, organoboronates, and Lewis acids. Lewis acids can also be used to facilitate a mild Friedel-Crafts reaction between electron-rich aromatics and allylic or benzylic alcohols. Moreover, these …
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Radiation-Induced Addition of Tritium to Carbon-Carbon Double Bonds
Made available in DSpace on 2014-12-05T19:38:03Z (GMT). No. of bitstreams: 1 6206209.pdf: 4034398 bytes, checksum: 86cbb3cff17ac376d35120e6caf3b249 (MD5) Previous issue date: 1962
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Selective, nickel-catalyzed carbon-carbon bond-forming reactions of alkynes
… desirable. Several novel, nickel-catalyzed carbon-carbon bond-forming reactions of alkynes that display excellent regioselectivity and (E/Z)-selectivity are described. These reactions afford synthetically useful allylic and homoallylic alcohols, often with high enantioselectivity. A highly …
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HYPERVALENT IODINE METHODS FOR CARBON–NITROGEN AND CARBON–CARBON BOND FORMATION
Carbon-carbon and carbon-nitrogen bond forming events are essential in chemistry. Although numerous stoichiometric/catalytic methods provided elegant and powerful solutions enabling those processes, the use of scarce/toxic reagents and harsh conditions is still ubiquitous in this field. As a …
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