Polyhedral Oligomeric Silsesquioxane Based Catalyst for the Efficient Synthesis of Cyclic Carbonates

In this work, the synthesis of a novel imidazolium-based polyhedral oligomeric silsesquioxane (POSS-mim-Cl) material is presented. The new nanometer-size organosilica based compound was employed for chemical fixation of CO2 into epoxide under homogeneous conditions. The target reaction was represented by the obtention of cyclic carbonates starting from epoxides and CO2. Particularly, styrene oxide was chosen as reference substrate. In addition, different parameters (solvent, temperature, pressure of CO2, and mass of the catalyst) were modified to find the best condition for CO2 conversion. The catalyst POSS-mim-Cl displayed good catalytic performances, the best results being obtained at 40 bar of CO2, 150°C, with 110 mg of catalyst and using isopropanol as co-solvent. It is worth to mention that POSS-mim-Cl displayed better catalytic performance than the corresponding 1-butyl-3-methyl imidazolium chloride. As far as we know this study represents the first use of imidazolium-based POSS as catalysts for the chemical fixation of CO2.