Fabrication of Highly Active and Stable Functionalized Polystyrene Catalysts for Cycloaddition of CO2 with Propylene Oxide

CO 2 activation represents a pivotal step in the CO 2 cycloaddition reaction with propylene oxide (PO) to form propylene carbonate (PC). This study prepared a chlorine-functionalized strongly alkaline polystyrene (CPS) catalyst via copolymerization and a TEAB/SiO 2 catalyst via silane coupling for CO 2 cycloaddition reactions. The CPS catalyst achieves nearly complete PO conversion (99.8%) with high selectivity (99.6%) towards PC and maintains a PC yield > 94% even after 10 reaction cycles. In contrast, the TEAB/SiO 2 exhibits rapid deactivation, with the PC yield declining from 66.8% to 5.1% after three cycles. Dynamically, the CPS catalyst exhibited a marked reduction in activation energy (20.1 kJ·mol −1 ) compared to TEAB/SiO 2 (32.9 kJ·mol −1 ), corroborating CO 2 activation through covalently anchored quaternary ammonium groups, which benefited from the higher alkalinity (2.65 mmol·g −1 ). Moreover, the outstanding stability of the CPS catalyst arises from the robust crosslinked framework of polystyrene and divinylbenzene. This work provides a strategic approach for designing alkaline catalysts and establishes a novel pathway to develop high-performance alternatives to ionic liquids for CO 2 activation in the cycloaddition reaction between CO 2 and PO. Graphical The alternative text for this image may have been generated using AI.