Rational design of Lewis acid-base bifunctional nanopolymers with high performance on CO2/epoxide cycloaddition without a cocatalyst

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 451; p. 138715
• Main Authors: Zhang, Wenwen, Ping, Ran, Lu, Xueyu, Shi, Huibing, Liu, Fusheng, Ma, Jingjing, Liu, Mengshuai
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2023
• Subjects: CO2 activation and conversion; Cyclic carbonate; Green medium; Multifunctional catalyst; Zwitterionic porous organic polymer; CO2 activation and conversion; Cyclic carbonate; Zwitterionic porous organic polymer; Multifunctional catalyst; Green medium
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.138715

Task-specific Py-Zn@IPOPX with multiple active sites are developed and exhibit durable high-activity for cycloaddition of CO2 to epoxides under additive-free conditions. [Display omitted] •Novel task-specific Py-Zn@IPOPX are constructed in green ionic liquid medium.•Py-Zn@IPOPI with multiple active sites can activate CO2 and epoxide simultaneously.•Py-Zn@IPOPI realizes efficient CO2 cycloaddition under additive-free conditions.•The developed catalyst is easily separated and exhibits durable high-activity. Based on the Schiff base reaction and post-modification strategy, novel nanocomposites of pyridine-zinc-based ionic porous organic polymers (Py-Zn@IPOPX, X  = Br, I, Ac) were constructed and structurally characterized. Various Py-Zn@IPOPX were applied to the transformation of CO2 and epoxides into cyclic carbonates, and their catalytic activities were studied and discussed in detail. The results showed that Py-Zn@IPOPI possesses Lewis acid-base bifunctional features, and also modified with superior nucleophilic active groups, which exerted an important synergistic effect on activation of CO2 and epoxide, and ring-opening of epoxide. Under co-catalyst/solvent-free conditions, Py-Zn@IPOPI could afford 96 % PC yield and 99 % selectivity at 120 °C and 2.0 MPa CO2 pressure for 6 h, and turnover frequency (TOF) was high to 230 h−1. Moreover, the reusability and versatility of the catalyst were examined, and the catalytic mechanism was speculated according to the obtained results. Compared with previously reported porous polymer catalysts, Py-Zn@IPOPI requires much greener and milder reaction conditions while avoids the use of a co-catalyst, displaying bright prospects for the design and synthesis of ionic porous organic polymers for CO2 activation and utilization.