Ammonium ionic liquids in separation of water/butan-1-ol using liquid-liquid equilibrium diagrams in ternary systems

Urszula Domańska-Żelazna , Michał Wlazło , Zbigniew Dąbrowski , Anna Wiśniewska

Abstract

In this work ionic liquids (ILs) as a novel popular solvents are proposed for removing butan-1-ol from the aqueous phase. Ternary liquid-liquid phase equilibrium data are presented for mixtures of {ionic liquid, IL (1) + butan-1-ol (2) + water (3)} at T = 328.15 K and pressure 101.3 kPa. The new synthesized by us ammonium-based ILs with long alkane chains, such as dimethyldodecylphenoxyethylammonium bis{(trifluoromethyl)sulfonyl}imide, [N1,1,12,2OPh][NTf2], dimethyldodecylphenoxyethylammonium dicyanamide, [N1,1,12,2OPh][DCA], benzyldimethyldodecylammonium bis{(trifluoromethyl)sulfonyl}imide, [N1,1,12,Bz][NTf2] and benzyldimethyldodecylammonium dicyanamide, [N1,1,12,Bz][DCA] have been tested. The selectivity and the solute distribution ratio of separation water/butan-1-ol were calculated and compared to the literature data. The complete solubility of butan-1-ol in the proposed ILs was observed at T = 328.15 K and pressure 101.3 kPa. The [N1,1,12,Bz][NTf2] is picked out as the most potential candidate as an extractant of butan-1-ol from water. The [N1,1,12,Bz][NTf2] shows only slightly lower selectivity than that observed in few phosphonium-based IL. The experimental tie-lines were successfully correlated with non-random two liquid NRTL model.