Determination of the viscosity of the ionic liquids [bmim][PF6] and [bmim][TF2N] under high CO2 gas pressure using sapphire NMR lubes

Abstract

The viscosities of the ionic liquids [bmim][PF6] and [bmim][TF2N] (bmim = 1-methyl-3-butylimidazolium, TF2N = bis(trifluoromethylsulfonyl)imide) have been determined under CO2 pressure at 298 K. The viscosity decreases from 381 to 23 cP for [bmim][PF 6] without CO2 and for 2.17 molal CO2 solutions (mole fraction XCO2 = 0.381, 55 bar CO2), respectively. For [bmim][TF2N] the viscosity decreases from 54 cP for the ionic liquid to 21 cP for a 1.61 molal solution of CO2 (mole fraction XCO2 = 0.403, 55 bar CO2). © 2008 Verlag der Zeitschrift für Naturforschung, Tübingen.