No abstract

Ionic liquids (ILs) containing the tris(pentafluoroethyl)trifluorophosphate anion [FAP]- have attracted increased attention due to their unique properties including ultrahigh hydrophobicity, hydrolytic stability, and wide electrochemical window. In this study, the solvation parameter model is used via gas chromatography to characterize the solvation interactions of seven ILs containing amino, ester, and hydroxyl functional groups appended to the cation and paired with [FAP]-, as well as three ILs containing the bis[(trifluoromethyl)sulfonyl]imide anion [NTf2]-. The role of the functional groups, nature of the counter anion, and cation type on the system constants were evaluated. ILs containing [FAP]- possessed lower hydrogen bond basicity than NTf2-based ILs having the same cationic component; in the case of hydroxyl-functionalized cations, the presence of [FAP]- led to an enhancement of the hydrogen bond acidity, relative to the NTf2-analogs. The system constants support the argument that [FAP]- weakly coordinates the cation and any appended functional groups, promoting properties of the cation which might be masked by stronger interactions with other anion systems. The chromatographic performance of the IL stationary phases was evaluated by examining the retention behavior and separation selectivity for chosen analytes. The results from this work can be used as a guide for choosing FAP-based ILs capable of exhibiting desired solvation properties while retaining important physical properties including high thermal stability and high hydrophobicity.

Block copolyimides based on aromatic dianhydrides and diamines copolymerized with diamino room temperature ionic liquid (RTIL) monomers were synthesized over a range of compositions. Specifically, two diamino RTILs, 1,3-di(3-aminopropyl) imidazolium bis[(trifluoromethyl)sulfonyl] imide ([DAPIM] [NTf 2 ]) and 1,12-di[3-(3-aminopropyl) imidazolium] dodecane bis[(trifluoromethyl) sulfonyl] imide ([C 12 (DAPIM) 2 ] [NTf 2 ] 2 ) were synthesized using a Boc protection method. The two RTILs were reacted with 2,2-bis(3,4-carboxylphenyl) hexafluoropropane dianhydride (6FDA) to produce 6FDA-RTILs oligomers that formed the RTIL component for the block copolyimides. The oligomers were reacted with 6FDA and m-phenylenediamine (MDA) at oligomer concentration from 6.5 to 25.8 mol % to form block copolyimides. Increasing the concentration of the 6FDA-RTIL oligomer in the block copolyimides resulted in a decrease in the thermal degradation temperature, glass transition temperature and an increase in the density. The gas permeability of the RTIL based block copolyimide decreased but the ideal permeability selectivity for CO 2 /CH 4 gas pair increased relative to the pure 6FDA-MDA. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: [4036][4037][4038][4039][4040][4041][4042][4043][4044][4045][4046] 2010

Two polymeric ionic liquids (PIL) were synthesized and employed as sorbent coatings in solid-phase microextraction (SPME) for the selective extraction of CO(2). The two coatings, poly(1-vinyl-3-hexylimidazolium) bis[(trifluoromethyl)sulfonyl]imide [poly(VHIM-NTf(2))] and poly(1-vinyl-3-hexylimidazolium) taurate [poly(VHIM-taurate)], exhibited varied selectivity toward CO(2) due to functional groups within in the PIL that imparted different mechanisms of CO(2) capture. Extraction efficiencies were compared to those of two commercial SPME fibers [poly(dimethylsiloxane) (PDMS) and Carboxen-PDMS]. The poly(VHIM-NTf(2)) PIL fiber exhibited comparable extraction efficiency at high CO(2) pressure compared to the Carboxen-PDMS fiber, even though the PIL-based fibers possessed much smaller film thicknesses. Calibration curves generated in pure CO(2) showed that the sensitivity of the poly(VHIM-NTf(2)) coating was comparable to that of the Carboxen-PDMS fiber with both PIL-based fibers exhibiting larger linear ranges and higher extraction-to-extraction reproducibility. The storage ability for selected fibers was examined and revealed that the PIL-based coatings exhibited superior capability in retaining the CO(2) sorbate on the fiber under different storage conditions, particularly for the poly(VHIM-taurate) PIL which reversibly captures CO(2) as a carbamate salt.