Design of Novel Poly(ionic liquids) for the Conversion of CO₂ to Cyclic Carbonates under Mild Conditions without Solvent

Abstract

The production of carbonates from carbon dioxide (CO2) and epoxides is an atom-economical reaction. This study developed a series of poly­(ionic liquids) (PILs) by copolymerizing a novel functional ionic liquid (ethyl ether bis­(1-vinylimidazolium) chloride) with ethylene glycol dimethacrylate (EGDMA). The structures and morphologies of PILs were investigated by adjusting the mole ratio between IL and EGDMA in the PILs. The prepared PILs were investigated as catalysts for the cycloaddition of CO2 with epoxides, and they show improved catalytic efficiency and accelerated mass transfer rate due to their mesoporous structure with a large number of uniformly distributed active ion sites. The PIL was stable, and the activity remained unchanged during the recycling of CO2 cycloaddition to epoxides under mild conditions without any solvent and co-catalyst. This study emphasizes the PIL as a versatile platform to obtain cyclic carbonates from CO2 under mild conditions.

Recent developments in organocatalysed transformations of epoxides and carbon dioxide into cyclic carbonates

“…In 2019, Gai et al developed a series of poly(ionic liquids) via the copolymerisation of bis(1-vinylimidazolium) chloride 49 ( Figure 20) with ethylene glycol dimethacrylate 162 to form catalysts, termed PIL-X where X is the molar ratio of 49 to ethylene glycol dimethacrylate. All the PIL-X catalysts showed abundant meso-or macroporous structures and the BET surface area of the polymer gradually decreased from 22.8 m 2 g -1 to 2.0 m 2 g -1 as the monomer 49 content in the polymer increased.…”

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

“…In the case of converting ECH, a high yield can be achieved at CO 2 atmospheric pressure at a very low temperature of 70 °C. As depicted in Scheme , other cross‐linkers such as ethylene glycol dimethacrylate (EGDMA) as an alternative to DVB can be also co‐polymerized with a few functionalized IL to generate a series of novel PILs . In contrast with the hydrophobicity of polystyrene backbones arising from its DVB moiety, the obtained PIL‐4 from ethyl ether bis(1‐vinylimidazolium) chloride and EGDMA exhibited low surface area and improved catalytic efficiency as well as a higher mass‐transfer rate.…”

“… Schematic representation of the synthesis of PIL‐4 via a multi‐component co‐polymerization strategy in the presence of a competitive polymerization …”

Nanoconfined Crosslinked Poly(ionic liquid)s with Unprecedented Selective Swelling Properties Obtained by Alkylation in Nanophase-Separated Poly(1-vinylimidazole)-l-poly(tetrahydrofuran) Conetworks

“…Another class of imidazole-based polymers belongs to poly(ionic liquid)s (PILs), that is macromolecules with ionic liquid (IL) moieties. Due to the challenging tasks of the synthesis, revealing the structure–property relationships, and the broad range of special application possibilities, PILs have been intensively investigated in recent years (see e.g., references [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 ] and references therein). PILs may find applications in energy production as proton [ 57 ], electron [ 58 , 59 ], or Li-ion [ 60 , 73 ] conducting materials; as metal free [ 61 ] and metal containing [ 62 ] catalysts; gas separation membranes [ 63 , 64 ]; DNA isolation microspheres [ 65 ] etc.…”

“…Although several applications require crosslinked PILs, PIL networks have not gained broad interest yet. The crosslinking usually takes place by copolymerizing IL monomers with conventional crosslinking agents, such as divinylbenzene and ethylene glycol dimethacrylate [ 43 , 69 , 70 , 71 ] or by bis-vinylimidazolium compounds [ 72 , 73 ]. In a few cases, low molecular weight poly(ethylene glycol) (PEG) di(meth)acrylate oligomers were used as crosslinkers in the preparation of PIL networks [ 41 , 74 , 75 , 76 , 77 , 78 , 79 ].…”