In the context of global warming, the conversion of a waste such as CO2 into valuable products is a particularly appealing research topic. The synthesis of cyclic carbonates from CO2 attracts the interest of the scientific community at both industrial and academic level. In order to promote this reaction a catalyst is needed. Ammonium or imidazolium salts are among the most known and active catalysts for this purpose. The high activity of imidazolium salts as catalysts can be further enhanced using a co-catalyst like Lewis acid sites able to decrease the activation energy of the reaction and hence to allow employing lower reaction temperatures. The utilization of heterogeneous catalysts easily recoverable and reusable is particularly beneficial according to the principles of Green Chemistry. The strategy employed in this PhD thesis focused on the synthesis of multifunctional heterogeneous catalysts prepared via functionalization of a mesoporous silica network with both imidazolium salts (catalyst) and various Lewis acids (co-catalyst). The materials were deeply characterized and a particular attention was dedicated to the investigation and the understanding of the interaction between the reactants and the Lewis acid site. All the solids were efficiently employed in the CO2 conversion displaying elevate activity and selectivity even at low temperature (below 100 °C).
|Date of Award
|11 Jun 2021
|Carmela Aprile (Supervisor), Guillaume Berionni (President), Paolo Pescarmona (Jury), Jean Marie Raquez (Jury) & Bruno Grignard (Jury)