The production of useful compounds through the chemical fixation of CO2 has attracted increasing
interest from the scientific community, due to its abundance in nature, non-toxicity and low-cost.
One of the most promising applications is the direct coupling of CO2 to epoxides for the production
of cyclic carbonates, which holds industrial interest, due to wide range of applications namely as
green solvents, electrolytes for lithium batteries and monomers for polymers production.
One technical barrier that needs to be addressed for wide industrial implementation, is the
separation and reutilization of catalysts, usually homogeneous Lewis acidic metal-based
complexes, combined with a nucleophile.
The aim of this thesis was to investigate the utilization of different ionic liquids and deep eutectic
solvents, potentially able to work both as reaction solvent and as co-catalyst, as well as to allow
the product separation from the reaction mixture. In this context, reaction conditions were
optimized, catalyst and several co-catalysts performances were studied. Different cation and
anion families of ionic liquids were also investigated, as well as deep eutectic solvents. Reactions
were performed in a high-pressure apparatus and final products analyzed by 1H-NMR
spectroscopy. Supercritical CO2 extraction was applied to separate the product from the reaction
mixture. The catalyst system was reused three times, without loss of activity.
The bromide anion and its combination with the tetrabutylammonium cation has shown the best
catalytic activity. However, its utilization as a solvent is not viable due to being solid at room
temperature. As a solvent, methyltrioctylammonium chloride showed promising results and
proved to be a good alternative to perform the reaction, since besides favouring the reaction
kinetic, it retains the catalyst allowing the product to be extracted using supercritical CO2.
Moreover, a tetrabutylammonium bromide (TBABr)-based deep eutectic solvent showed the best
performance as solvent and co-catalyst and constitutes a good alternative for further studies