Sökning: "support reactions"

Visar resultat 1 - 5 av 263 avhandlingar innehållade orden support reactions.

  1. 1. Electrochemical Reactions in Polymer Electrolyte Fuel Cells

    Detta är en avhandling från Stockholm : KTH

    Författare :Maria Wesselmark; Svein Sunde; [2010]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fuel cell; model electrodes; oxygen reduction; methanol oxidation; formic acid oxidation; hydrogen oxidation; CO oxidation; degradation; tungsten oxide; carbon support; Bränslecell; modellelektroder; syrgasreduktion; metanoloxidation; myrsyraoxidation; vätgasoxidation; CO oxidation; degradering; wolfram oxid; kolsupport; TECHNOLOGY Chemical engineering; TEKNIKVETENSKAP Kemiteknik;

    Sammanfattning : The polymer electrolyte fuel cell converts the chemical energy in a fuel, e.g. hydrogen or methanol, and oxygen into electrical energy. The high efficiency and the possibility to use fuel from renewable sources make them attractive as energy converters in future sustainable energy systems. LÄS MER

  2. 2. Heck Reactions with Aryl Chlorides Studies of Regio- and Stereoselectivity

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Gopal K. Datta; Mats Larhed; Anders Hallberg; Martin Oestreich; [2008]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Heck reaction; aryl chloride; vinyl ether; regioselective; stereoselective; palladium; chelation control; microwave; PHARMACY Pharmaceutical chemistry; FARMACI Farmaceutisk kemi;

    Sammanfattning : Homogeneous palladium-catalyzed Heck vinylation of aryl chlorides was investigated under air using Herrmann’s palladacycle and the P(t-Bu)3-liberating salt [(t-Bu)3PH]BF4. Based on the results, controlled microwave heating was utilized to accelerate model Heck reactions with aryl chlorides down to 30 min employing an electron-poor olefin and a mixture of an ionic liquid and 1,4-dioxane as solvent. LÄS MER

  3. 3. Ruthenium-Catalyzed Hydrogen Transfer Reactions Mechanistic Studies and Chemoenzymatic Dynamic Kinetic Resolutions

    Detta är en avhandling från Stockholm : Department of Organic Chemistry, Stockholm University

    Författare :Madeleine Warner; Jan-Erling Bäckvall; Andreas Pfaltz; [2013]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hydrogen transfer; ruthenium catalysis; kinetic resolution; dynamic kinetic resolution; racemization; asymmetric synthesis; Organic Chemistry; organisk kemi;

    Sammanfattning : The main focus of this thesis lies on transition metal-catalyzed hydrogen transfer reactions. In the first part of the thesis, the mechanism for racemization of sec-alcohols with a ruthenium complex, Ru(CO)2Cl(η5-C5Ph5) was studied. LÄS MER

  4. 4. Transition Metal-Catalyzed Redox Reactions A Journey from Homogeneous Ruthenium to Heterogeneous Palladium Catalysis

    Detta är en avhandling från Stockholm : Department of Organic Chemistry, Stockholm University

    Författare :Oscar Verho; Jan-Erling Bäckvall; Manfred Reetz; [2013]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic Chemistry; organisk kemi;

    Sammanfattning : The first part of the thesis covers the development and utilization of electronically modified (pentaarylcyclopentadienyl)Ru-complexes in the racemization of secondary alcohols. This study revealed that the electronic properties of the substrate were the main factors dictating whether β-hydride elimination or hydride re-addition becomes the rate-determining step of the racemization process. LÄS MER

  5. 5. Shear in Concrete Structural Elements Subjected to Dynamic Loads

    Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

    Författare :Johan Magnusson; Anders Ansell; Mikael Hallgren; Richard Malm; Jaap Weerheijm; [2019]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dynamic load; initial response; shear failure; shear capacity; numerical simulations; bond; shear span; support reactions; Dynamisk last; initial respons; skjuvbrott; skjuvkapacitet; numeriska simuleringar; förankring; skjuvspännvidd; upplagsreaktioner; Civil and Architectural Engineering; Byggvetenskap;

    Sammanfattning : Concrete structural elements subjected to severe dynamic loads such as explosions at close range may cause shear failures. In the Oklahoma City bombing in 1995 two concrete columns on the ground level were reported to have failed in shear. LÄS MER