Ionic Polyurethanes as a New Family of Poly(ionic liquid)s for Efficient CO₂ Capture

Abstract

Carbon dioxide (CO2) levels are continuously growing, and CO2 is believed to be a significant contributor to global warming and climate change. Therefore, there is a great interest in the development of highly efficient technologies to curb CO2 emissions of current energy sources. In this context to combat such issues, poly­(ionic liquid)­s (PILs) offer an extremely versatile and tunable platform to fabricate a wide variety of sorbents for CO2 capture. To date, the majority of poly­(ionic liquid)­s studied for CO2 capture is related to carbochain polymers (acrylate and styrene polyelectrolytes), while it is generally accepted that polymers with more basic backbones such as amides, urethanes or amidoxines can considerably enhance the CO2 absorption capacity. Thus, a series of novel high molecular weight (M n = (3.4–21.0) × 104) ionic polyurethanes (PUs) have been prepared using four different ionic diols based on ammonium, quinuclidinium, diquinuclidinium and imidazolium cations. Furthermore, a range of ionic PUs bearing 13 different counteranions including classical ((CF3SO2)2N, BF4, PF6, and N­(CN)2) and less encountered anionic species such as acetate, lactate, tetracyanoborate, bis­(pentafluoroethylsulfonyl)­amide, CF3SO2–N–CN and MeHal n (Me = Fe­(III), Cu­(II), Zn­(II), Hal = Cl, Br) was obtained through the ion exchange reactions using the same bromide PU precursor. This allowed to separately isolate the effect of diisocyanate, cations and anions nature on physical properties of ionic PUs. The obtained poly­(ionic liquid)­s demonstrate high thermal stability (up to 275 °C), have glass transition temperatures in the range of 30–78 °C and show remarkable CO2 capture. It was found that ionic PUs incorporating diquinuclidinium cation and CH3COO or BF4 anions exhibit the highest CO2 sorption (18.25 and 24.76 mg/g at 273 K and 1 bar), not only overcoming the CO2 capture reported to date for linear PILs, but even surpassing the highest value known for cross-linked meso-porous poly­(ionic liquid)­s (20.24 mg/g at 273 K and 1 bar). Altogether, this paper demonstrates the potential of poly­(ionic liquid)­s as efficient designing materials for CO2 capture.

Effect of Pore Size on the Carbon Dioxide Adsorption Behavior of Porous Liquids Based on Hollow Silica

“…Existing CO 2 capturem ethods including physicals orbents by porousm aterials, [13][14][15][16] andc hemical sorbents [17] such as aqueous ammonia solution, [18] suffer from variousp roblems. [19][20][21] Compared with conventional solid silica nanofluids, [22,23] porous liquids have better gas capture capacity due to the permanent cavities.…”

Design, synthesis, and gas permeation properties of polyimides containing pendent imidazolium groups

“…8,9 In the recent years, polymers containing ionic groups have gained significant attention for various applications in the fields such as gas separation, lithium ion batteries, protonexchange membrane fuel cells (PEMFC), supercapacitors, and so forth. [10][11][12][13][14][15][16][17][18][19][20] It has been demonstrated that polymers containing ionic groups exhibit excellent gas permeation properties and their gas permeation properties can be tuned by varying compositions of ionic groups. 13 For CO 2 separation, polymers containing ionic groups showed high selectivity and high permeability because of interaction of ionic counterpart with CO 2 .…”

Solid‐State Poly(ionic liquid) Gels for Simultaneous CO2 Adsorption and Electrochemical Reduction

“…[22] Poly(ionic liquids) (PILs), polymers derived from monomers basedo nI Ls,h ave also been investigated for CO 2 capturing. [23][24][25][26] PILs are ionically conductive and their CO 2 adsorption capacity is between 2a nd 20 mg g À1 ,which is higher than their IL counterparts. [2,[27][28][29][30][31] Managing carbon dioxide (CO 2 )r eleased from large-scale industrialp rocesses is of great importance,y et there remain significant technical challenges.H erein, the fabrication of 1mm-thicks olid-state electrochemical devices based on poly-(ionic liquid) ionogels with embedded electrodes capable of both adsorption and electrochemical reduction of CO 2 is reported.T he ionogelsa re prepared via radical polymerization and chemical crosslinking of avinyl imidazolium trifluoromethanesulfonimide ionic liquid monomer in the presence of additional ionic liquids (ILs) that act as swellinga gents and enhance ionic conductivity.…”