Poly(ionic liquid)–ionic liquid membranes with fluorosulfonyl derived anions: characterization and biohydrogen separation

Unformatted postprintClean and sustainable energy production has become a key global issue concerning the world’s energy shortage and environmental problematic. Despite the recognized potential of biohydrogen (bioH2) for sustainable development, there are still issues regarding its production and purification, such as the elimination of CO2, N2, and other impurities (H2O and H2S), so that an enriched H2 stream can be obtained for efficient energy generation. The use of poly(ionic liquid)s (PILs) and their derived composite materials incorporating ionic liquids (PIL–IL) has been considered as a highly promising strategy to design membranes with improved CO2 separation. In this study, membranes of pyrrolidinium-based PILs containing symmetric or asymmetric fluorosulfonyl derived anions, namely bis(fluorosulfonyl)amide ([FSI]–), (trifluoromethyl)sulfonyl-N-cyanoamide ([TFSAM]–) and (trifluoromethyl)sulfonyl-N-trifluoroacetamide ([TSAC]–), were prepared by the incorporation of different amounts of structurally similar ILs. The PIL–IL membranes were characterized by different techniques (TGA, DSC, FT-IR and Raman) and their CO2/H2 and H2/N2 separation performances were investigated. Higher CO2/H2 selectivities were obtained for PIL FSI–40 [C2mim][FSI] (αCO2/H2 = 9.0) and PIL TFSAM–40 [C2mim][TFSAM] (αCO2/H2 = 7.1) compared to those of PIL–IL membranes containing the conventional [TFSI]– anion at similar or even higher amounts of IL’s incorporation.Andreia S. L. Gouveia is grateful to FCT (Fundação para a Ciência e a Tecnologia) for her Doctoral (SFRH/BD/116600/2016) research grant. Liliana C. Tomé has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 745734. This work was supported by FCT through the project PTDC/CTM-POL/2676/2014. Centro de Química Estrutural acknowledges the financial support of Fundação para a Ciência e Tecnologia (UIDB/00100/2020). Elemental analysis and Raman spectroscopy were performed with the financial support from Ministry of Science and Higher Education of the Russian Federation using the equipment of Center for molecular composition studies of INEOS RAS

A New Volume-Based Approach for Predicting Thermophysical Behavior of Ionic Liquids and Ionic Liquid Crystals

Volume-based prediction of melting points and other properties of ionic liquids (ILs) relies on empirical relations with volumes of ions in these low-melting organic salts. Here we report an accurate way to ionic volumes by Bader’s partitioning of electron densities from X-ray diffraction obtained via a simple database approach. For a series of 1-tetradecyl-3-methylimidazolium salts, the volumes of different anions are found to correlate linearly with melting points; larger anions giving lower-melting ILs. The volume-based concept is transferred to ionic liquid crystals (ILs that adopt liquid crystalline mesophases, ILCs) for predicting the domain of their existence from the knowledge of their constituents. For 1-alkyl-3-methylimidazolium ILCs, linear correlations of ionic volumes with the occurrence of LC mesophase and its stability are revealed, thus paving the way to rational design of ILCs by combining suitably sized ions

A New Volume-Based Approach for Predicting Thermophysical Behavior of Ionic Liquids and Ionic Liquid Crystals

Volume-based prediction of melting points and other properties of ionic liquids (ILs) relies on empirical relations with volumes of ions in these low-melting organic salts. Here we report an accurate way to ionic volumes by Bader’s partitioning of electron densities from X-ray diffraction obtained via a simple database approach. For a series of 1-tetradecyl-3-methylimidazolium salts, the volumes of different anions are found to correlate linearly with melting points; larger anions giving lower-melting ILs. The volume-based concept is transferred to ionic liquid crystals (ILs that adopt liquid crystalline mesophases, ILCs) for predicting the domain of their existence from the knowledge of their constituents. For 1-alkyl-3-methylimidazolium ILCs, linear correlations of ionic volumes with the occurrence of LC mesophase and its stability are revealed, thus paving the way to rational design of ILCs by combining suitably sized ions

Ionic Polyureas—A Novel Subclass of Poly(Ionic Liquid)s for CO2 Capture

The growing concern for climate change and global warming has given rise to investigations in various research fields, including one particular area dedicated to the creation of solid sorbents for efficient CO2 capture. In this work, a new family of poly(ionic liquid)s (PILs) comprising cationic polyureas (PURs) with tetrafluoroborate (BF4) anions has been synthesized. Condensation of various diisocyanates with novel ionic diamines and subsequent ion metathesis reaction resulted in high molar mass ionic PURs (Mw = 12 ÷ 173 × 103 g/mol) with high thermal stability (up to 260 °C), glass transition temperatures in the range of 153–286 °C and remarkable CO2 capture (10.5–24.8 mg/g at 0 °C and 1 bar). The CO2 sorption was found to be dependent on the nature of the cation and structure of the diisocyanate. The highest sorption was demonstrated by tetrafluoroborate PUR based on 4,4′-methylene-bis(cyclohexyl isocyanate) diisocyanate and aromatic diamine bearing quinuclidinium cation (24.8 mg/g at 0 °C and 1 bar). It is hoped that the present study will inspire novel design strategies for improving the sorption properties of PILs and the creation of novel effective CO2 sorbents.This research was in part supported by Fonds National de la Recherche Luxembourg (FNR) with Agency Nationale de la Recherche (ANR) through the ANR-FNR project DISAFECAP (Agreement number INTER/ANR/18/13358226). Partial funding by the Spanish Agencia Estatal de Investigación (AEI), PCTI 2013-2017 del Principado de Asturias and ERDF through projects RTI2018-100832-B-I00 and IDI/2018/000233 is gratefully acknowledged. Partial funding by Russian Foundation for Basic Research (RFBR) through project 16-03-00768_a is acknowledged. Elemental analysis and IR spectroscopy were performed with the financial support from Ministry of Science and Higher Education of the Russian Federation using the equipment of Center for molecular composition studies of INEOS RAS.Peer reviewe

Supramolecular ionic networks with superior thermal and transport properties based on novel delocalized di-anionic compounds

Supramolecular ionic networks based on highly delocalized dianions having (trifluoromethane-sulfonyl)imide, (propylsulfonyl)methanide and (cyano-propylsulfonyl)imide groups were developed and their physical properties were examined in detail. Most of the synthesized compounds were semi-crystalline possessing Tm values close to 100°C; however, amorphous networks were also obtained using aromatic asymmetric dianions. Rheological measurements in temperature sweep tests at a constant frequency confirmed two different behaviors: a fast melting close to the Tm for semi-crystalline materials and a thermoreversible network for liquid transition for the amorphous supramolecular ionic networks. It was found that the amorphous ionic networks showed significantly higher ionic conductivity (10-3 S cm-1 at 100°C) than the crystalline ionic networks (10-6 S cm-1) and previously reported amorphous citrate ionic networks (10-5 S cm-1). The supramolecular ionic networks containing hydrophobic (trifluoromethanesulfonyl)imide groups demonstrated improved water stability and higher thermal stability than the previously synthesized carboxylate ones. Noticeably, the obtained amorphous supramolecular ionic networks combine not only high ionic conductivity and thermal stability, but also self-healing properties into the same material

Tunning CO2 Separation Performance of Ionic Liquids through Asymmetric Anions

This work aims to explore the gas permeation performance of two newly-designed ionic liquids, [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2], in supported ionic liquid membranes (SILM) configuration, as another effort to provide an overall insight on the gas permeation performance of functionalized-ionic liquids with the [C2mim]+ cation. [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2] single gas separation performance towards CO2, N2, and CH4 at T = 293 K and T = 308 K were measured using the time-lag method. Assessing the CO2 permeation results, [C2mim][CF3BF3] showed an undermined value of 710 Barrer at 293.15 K and 1 bar of feed pressure when compared to [C2mim][BF4], whereas for the [C2mim][CF3SO2C(CN)2] IL an unexpected CO2 permeability of 1095 Barrer was attained at the same experimental conditions, overcoming the results for the remaining ILs used for comparison. The prepared membranes exhibited diverse permselectivities, varying from 16.9 to 22.2 for CO2/CH4 and 37.0 to 44.4 for CO2/N2 gas pairs. The thermophysical properties of the [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2] ILs were also determined in the range of T = 293.15 K up to T = 353.15 K at atmospheric pressure and compared with those for other ILs with the same cation and anion’s with similar chemical moieties

Bis(trifluoromethylsulfonyl)amide based "polymeric ionic liquids": Synthesis, purification and peculiarities of structure-properties relationships

A series of bis(trifluoromethylsulfonyl)amide based "polymeric ionic liquids" (PILs) as high molecular mass analogues of the corresponding imidazolium, ammonium and pyrrolidinium ionic liquids (ILs) was synthesized with high purity and fully characterized including electrochemical properties. The PILs differed by the nature of the cation, the quantity of the ionic centers in each monomer repeating unit, and the alkyl length of the spacer. Two novel ionic liquid like monomers (ILMs), namely 1,3-bis(N,N,N-trimethylammonium)-2-propylmethacrylate bis(trifluoromethylsulfonyl) amide (ILM-2) and N-[(2-methacryloyloxy)-ethyl]-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (ILM-4) were synthesized and characterized. Optimal conditions for the free-radical polymerization of the ILMs were identified for the first time. It was demonstrated that, among the tested organic solvents, 1-methyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)amide IL was the best reaction medium in terms of the achievement of high polymer yields and molecular masses. For the first time, the influence of the residual monomer presence inside the PIL film on the resultant conductivity was clearly shown. The impact of the molecular mass of the PILs on the ionic conductivity was firstly studied as well. Finally, the copolymerization of ILMs with poly(ethylene glycol)dimethacrylate (PEGDM) was carried out yielding tight elastic films with the highest conductivity equal to 3.2 x 10(-6) S/cm at 25 degrees C. (C) 2011 Elsevier Ltd. All right

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

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 (<i>M</i>_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, PF_6, and N­(CN)₂) and less encountered anionic species such as acetate, lactate, tetracyanoborate, bis­(pentafluoroethylsulfonyl)­amide, CF₃SO₂–N–CN and MeHal_<i>n</i> (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