Polymerization of CO2\PO Using Zeolite MCM-22-Encapsulated Salen-Co(III)-OAc

Introduction: The copolymerization of carbon dioxide (CO2) and propylene oxide (PO) catalyzed by salen-Co(III)-OAc is an effective method to mitigate the greenhouse effect caused by carbon dioxide. Objective: This study aimed to improve the activity and stability of the salen-Co(III)-OAc catalyst and simplify the separation of catalyst and polymer. Methods: MCM-22 encapsulation strategy of salen-Co(III)-OAc was adopted, and the structure of catalyst was tested by ICP, UV-vis, SEM, TEM, EDS-mapping, XRD, and FT-IR techniques. Results: Under a PO/Catalyst ratio of 15000:1, salen-Co(III)-OAc exhibited a turnover frequency (TOF) of 350 h-¹, whereas the encapsulated variant achieved an enhanced TOF of 402 h-¹ under identical conditions. The improved activity of MCM-22-encapsulated salen-Co(III)-OAc can be attributed to its synergistic interaction resembling a “zeolite enzyme”. Conclusion: MCM-22 can encapsulate salen-Co(III)-OAc, improving catalyst activity and stability, while simplifying catalyst recovery and product purification.