Recent Advances on Imidazolium‐Functionalized Organic Cationic Polymers for CO₂ Adsorption and Simultaneous Conversion into Cyclic Carbonates

Abstract

The cycloaddition reaction of CO2 with various epoxides to generate cyclic carbonates is one of the most promising and efficient approaches for CO2 fixation. Typical imidazolium‐based ionic liquids possessing electrophilic cations and nucleophilic halogen anions have been identified as excellent and environmentally friendly candidates for synergistically activating epoxides to convert CO2. Therefore, the feasible construction of a series of imidazolium‐functionalized organic cationic polymers can bridge the gap between homogeneous and heterogeneous catalysis, thereby obtaining highly selective CO2 adsorption and simultaneous conversion ability. This Review describes the recent advancements made with regard to the design and synthesis of this type of polymeric networks having imidazolium functionality. They are considered as an outstanding heterogeneous catalyst for the cycloaddition of CO2 to epoxides. Based on the perspective from the design of building blocks to the synthesis of cationic polymers, the focus mainly lies on how to introduce imidazole units into the material backbone via a covalent linking approach and how to incorporate other active sites capable of activating CO2 and/or epoxides into such polymeric materials.

Preparation of Nanofibers Mats Derived from Task-Specific Polymeric Ionic Liquid for Sensing and Catalytic Applications

“…Advanced materials based on PILs have been used as efficient systems for the capture, activation and conversion of CO 2 [ 31 ]. For instance, different polymers containing IL-like moieties have been reported as efficient catalysts for the cycloaddition reaction of CO 2 with various epoxides to generate cyclic carbonates, which is one of the most promising and efficient approaches for CO 2 fixation [ 32 ]. In this context, the modified mat 14 was studied for the catalytic reaction of styrene oxide with CO 2 .…”

Emerging Ionic Polymers for CO

“…Recent reviews have focussed on the design of and progress around ionic polymers for the CO 2 cycloaddition reaction, [14,16,18,21,22] with minor mentions of poly(ionic liquid)s or ionic polymers. To our knowledge, only one review focussed only on imidazolium-functionalized ionic polymers as heterogeneous catalysts, only partially addressing the subject reviewed here.…”

“…[17] To bridge the gap between homogeneous and heterogeneous catalysts in the CO 2 -epoxide coupling reaction, organic polymers have emerged over the past several years as efficient catalysts with unprecedented inherent structural features. [16,[18][19][20] The main feature of these polymers is that they are ionic in nature and include many ionic groups such as cations and anions similar to the ones used in ionic liquid chemistry (shown in Fig. 2).…”

Covalent Triazine Frameworks Obtained from Nitrile Monomers for Sustainable CO2 Catalysis

“…[11] In principle, the possible mechanism often follows two catalytic cycles in the CO 2 cycloaddition with epoxide: one is the nucleophilic attack on the electrophilic carbon of CO 2 , and the initial step may be promoted by nucleophiles such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and Nheterocyclic carbenes (NHCs), which is regarded as a CO 2 activation route; the other approach happens on the less hindered carbon atom of an epoxide, and the nucleophilic counteranions enable the ring-opening step, which is called an epoxide activation pathway (Scheme 3). [12] Thus it can be seen that the well-designed CTFs with abundant tailorable functional groups and permanent nanoporosities can be employed as an ideal heterogeneous catalyst for CO 2 conversion into cyclic carbonates.…”