Fabrication of Amine and Zirconia on MCM-41 as Acid-Base Catalysts for the Fixation of Carbon Dioxide

Highly porous catalysts based on MCM-41 with both acidic and basic sites such as ZrO2 as an acid and (3-aminopropyl)triethoxysilane as a mild base are fabricated and characterized thoroughly by using XRD, SEM, thermogravimetric analysis, temperature-programmed reduction, desorption, oxidation, BET surface area analysis, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and IR spectroscopy. This catalyst shows a synergistic effect for the activation of epoxide as well as CO2 to synthesize cyclic carbonates. The presence of the free amine functional group activates CO2 by absorption, whereas the presence of Zr metal activates the epoxide ring. The effect of the amine and catalyst loading on the cycloaddition reaction was studied. Additionally, the cycloaddition reaction proceeds under solvent-free and mild conditions, and the catalysts are recyclable.