Influence of Fluorination on the Solubilities of Carbon Dioxide, Ethane, and Nitrogen in 1-n-Fluoro-alkyl-3-methylimidazolium Bis(n-fluoroalkylsulfonyl)amide Ionic Liquids

Abstract

The effect on gas solubilities of adding partially fluorinated alkyl side chains either on imidazolium-based cations or on bis(perfluoroalkylsulfonyl)amide anions was studied. The aim was to gain knowledge of the mechanisms of dissolution of gases in fluorinated ionic liquids and, if possible, to improve physical absorption of carbon dioxide in ionic liquids. We have determined experimentally, in the temperature range of 298-343 K and at pressures close to atmospheric pressure, the solubility and thermodynamics of solvation of carbon dioxide, ethane, and nitrogen in the ionic liquids 1-octyl-3-methylimidazolium bis[trifluoromethylsulfonyl]amide ([Cmim][NTf]), 1-octyl-3-methylimidazolium bis[pentafluoroethylsulfonyl]amide ([Cmim][BETI]), 1-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)-3-methylimidazolium bis[trifluoromethylsulfonyl]amide ([CHFmim][NTf]), and 1-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)-3-methylimidazolium bis[pentafluoroethylsulfonyl]amide ([CHFmim][BETI]). Ionic liquids with partial fluorination on the cation were found to exhibit higher carbon dioxide and nitrogen mole fraction solubilities but lower ethane solubilities, compared to those of their hydrogenated counterparts. Molecular simulation provided insights about the mechanisms of solvation of the different gases in the ionic liquids.

Phase-out-compliant fluorosurfactants: unique methimazolium derivatives including room temperature ionic liquids

“…115 All the more, statutory phaseout regulations, succinctly termed "the Shrinking Case for Fluorochemicals", 113 as well as public alertness should stimulate and promote further dedicated exploration of preferably short chain 116 fluoro surfactant constituents. And indeed, in this green context, pushed by the goals of utmost harm reduction, topical research is just about to gain momentum, and again starts to unravel new stunning interrelations of their toxicological, 117 as well as physicochemical property profiles, 118 especially details of micelle formation 119 and lyotropic behavior. 47,120 Unfortunately, the adequate coverage of all relevant multidisciplinary aspects, including comprehensive ecotoxicological research, 121 represents a burden, as it is almost impossible to predict the toxicity of organic fluorine compounds on the basis of chemical structure related elements.…”

Fluorine-functionalized ionic liquids with high oxygen solubility

“…[56][57][58][59][60][61] An alternative approach is via peruorinated alkyl chains in the anion. [62][63][64][65] However, this approach leads in general to ionic liquids with higher melting points.…”

Direct experimental observation of mesoscopic fluorous domains in fluorinated room temperature ionic liquids

“…Aiming at developing task-specific ILs with specific activity triggered by appropriate functionalisation, Davis and co-workers prepared a series of imidazolium based ILs bearing two side chains, one of them being fluorinated. 24 This kind of FIL has been studied by different groups that aimed for example to describe structural and other kind of properties using a merging of experimental and computational techniques [25][26][27][28][29][30] Other ILs containing fluorous moieties have been proposed later on (see e.g. [31][32][33][34] ).…”