Leila Moura, W. Darwich, C. Santini
Nov 15, 2015
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Influential Citations
41
Citations
Journal
Chemical Engineering Journal
Abstract
Abstract The density, viscosity and absorption of ethane and ethylene were determined experimentally, as a function of temperature and at atmospheric pressure, in different imidazolium-based ionic liquids: 1-methyl-3-octylimidazolium bis(trifluoromethanesulfonyl)imide, [C 1 C 8 Im][NTf 2 ], 1-methyl-3-(propyn-3-yl)imidazolium bis(trifluoromethanesulfonyl)imide [C 1 (C 2 H 2 CH)Im][NTf 2 ], 1-(3-cyanopropyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C 1 C 3 CNIm][NTf 2 ], 1-(3-cyanopropyl)-3-methylimidazolium dicyanamide [C 1 C 3 CNIm][DCA], 1-butyl-3-methylimidazolium dicyanamide, [C 1 C 4 Im][DCA] and 1-butyl-3-methylimidazolium methylphosphite [C 1 C 4 Im][C 1 HPO 3 ]. The densities and viscosities of the ionic liquids studied are strongly dependent on the anion and, at 313 K, follow the order: [C 1 (C 2 H 2 CH)Im][NTf 2 ] > [C 1 C 3 CNIm][NTf 2 ] > [C 1 C 3 CNIm][DCA] > [C 1 C 4 Im][C 1 HO 3 ] > [C 1 C 4 Im][DCA] and [C 1 C 3 CNIm][NTf 2 ] > [C 1 C 3 CNIm][DCA] > [C 1 C 4 Im][C 1 HPO 3 ] > [C 1 (C 2 H 2 CH)Im][NTf 2 ] > [C 1 C 4 Im][DCA], respectively. The differences in the molecular structures of the ionic liquids allowed the identification of the influence of increasing the alkyl side chain of the cation, of the presence of unsaturated C C and C N bonds on the alkyl side chain of the cation and finally of a phosphite based anion on the selective absorption of ethane and ethylene. The solubility of ethylene is higher than that of ethane in the ionic liquids studied and varies from 18.41 × 10 −3 in [C 1 C 8 Im][NTf 2 ] at 303.17 K to 1.603 × 10 −3 in [C 1 C 4 Im][DCA] at 343.61 K. The introduction of the different functional groups leads to a decrease on the gas absorption compared with that of [C 1 C 8 Im][NTf 2 ] but to an increase of the ideal separation selectivity of ethane and ethylene.