Novel imidazolium based catalysts for the chemical fixation of carbon dioxide

  • Ornella Fichera

    Student thesis: Master typesMaster en sciences chimiques

    Résumé

    The use of carbon dioxide as feedstock for chemicals and fuels has become a very attractive topic. The major challenges linked to the storage and transport of CO2 could be overcome by its direct conversion into useful products. However due to its thermodynamic and kinetic stability, its conversion is difficult to achieve and an efficient catalyst is required. One of the most promising sustainable reactions in terms of catalyst performance is the chemical fixation of CO2 onto epoxides to produce cyclic carbonates. The reasons of the growing interest in this synthesis stand mainly in the possibility to transform a non-toxic, abundant, economical and renewable “waste”, such as CO2, into valuable products. Various homogeneous and heterogeneous processes have been proposed for this reaction. Catalysts based on transition metal complexes have proved their efficiency in terms of both yield and selectivity. Application of organocatalysts such as ionic liquids can be in most cases more advantageous respect to them, not only in terms of price or stability but also from an environmental point of view since their use avoid metallic wastes. In addition, it was recently found that imidazolium ionic liquids are active catalysts for the chemical fixation of CO2. Here, the synthesis and applications of novel imidazolium based catalysts are presented. The nanosized structures selected in this work for the anchoring of the imidazolium moiety are (1) the polyhedral oligomeric silsesquioxane (POSS) and (2) the CO2 fullerene. The comparison in terms of catalytic behaviour between POSS and fullerene catalysts functionalized respectively with eight and twelve imidazolium units can be interesting due to their similar nanocage structure. The first part of the present work was dedicated to the synthesis and characterization of the imidazolium based catalysts while in the second one the catalytic performances of these materials will be tested in the chemical fixation of CO2.
    la date de réponsejanv. 2015
    langue originaleAnglais
    L'institution diplômante
    • Universite de Namur
    SuperviseurCarmela Aprile (Promoteur)

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