Design of bifunctional NH3I-Zn/SBA-15 single-component heterogeneous catalyst for chemical fixation of carbon dioxide to cyclic carbonates

The novel bifunctional Zn/SBA-15 supported ammonium salt (NH 3 I-Zn/SBA-15) as single-component heterogeneous catalyst for the coupling of CO 2 with epoxides was developed. FT-IR, XRD, N 2 adsorption/desorption, TEM, XPS techniques were used to determine the morphological structure and physicochemical properties of NH 3 I-Zn/SBA-15 sample. The catalyst exhibited exceptionally effective activity with 93% yield and 99% selectivity and a high TOF of 306   h −1 to propylene carbonate at 130   °C and 3   MPa of CO 2 for 12   h in the absence of cocatalyst and solvent participation. Also the catalytic system was versatile to the cycloadditions of other epoxides with CO 2 under the optimized reaction conditions. Additionally, the catalyst was easily recycled and reused only with slight loss of activity after five recycles. Besides, a possible catalytic mechanism involving cooperative activation of epoxide and ring-opening by one-component and bifunctional catalyst was proposed. The protocol herein provides important insights on design of novel single-component heterogeneous catalysts for CO 2 relevant transformations.