One of the strategies of solving greenhouse problem is transformation CO₂ to valuable chemicals such as carbamates, cyclic carbonates, oxazolidones and tetramic acids. Among these chemicals, cyclic carbonates can be used in lithium-ion batteries as electrolyte. Cyclic carbonate production via CO₂ cycloaddition is feasible way in terms of thermodynamic and atom economy. However, CO₂ transformation processes require high energy. So, researchers have been studied several catalysts which possess high CO₂ uptake capacity such as zeolites, porous carbon, metal organic frameworks (MOFs). As a novel class of porous materials, Covalent Organic Frameworks (COFs) can be achieve success even under humid conditions in cyclic carbonate production via CO₂ cycloaddition [1]. The unique properties of COFs are low density, large surface area, adjustable pore size and structure [2]. One of the studies of this area was Tong et al. (2022). They synthesized salen-COF via solvothermal method and impregnated cobalt on this catalyst. Under the optimized conditions (22.5 mg Co-based catalyst, 20 bar, 120 °C, solvent-free), researchers obtained 99% propylene carbonate selectivity and 98% propylene oxide conversion [3]. Haque et al. (2021) synthesized Zn embedded RIO-1. They carried out the reaction at room temperature under 1 atm CO₂ pressure. After 10 h reaction time, they obtained 100% α-alkylidene cyclic carbonate selectivity for cyclic carbonates and 100% propargyl alcohol conversion [4].

[1] Sengupta, M., Bag, A., Ghosh, S., Mondal, P., Bordoloi, A., & Islam, S. M., Journal of CO2 Utilization, 2019, 34, 533-542. [2]Ding, S. Y., & Wang, W., Chemical Society Reviews, 2013, 42(2), 548-568. [3]Tong, Y., Cheng, R., Dong, H., & Liu, B. Journal of Porous Materials, 2022, 29, 1253–1263. [4]Haque, N., Biswas, S., Ghosh, S., Chowdhury, A. H., Khan, A., & Islam, S. M. ACS Applied Nano Materials, 2021, 4(8), 7663-7674.