Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The viscosity, density, and electrical conductivity of 1-hexyl-3-methylimidazolium bis(trifluorosulfonyl)imide have been measured at temperatures from (288 to 433) K and at pressures up to 50 MPa. A vibrating wire viscometer was used for the measurements of viscosity that have an expanded uncertainty (k ) 2) of ( 2 %. The density was obtained from a vibrating tube densimeter with an expanded uncertainty (k ) 2) of ( 0.3 %. The electrical conductivity (f fyen) was determined from impedance measurements at frequencies in the range (0.5 to 10) kHz with an expanded (k ) 2) uncertainty of ( 2 %. All measurements were conducted with a sample distributed by NIST as part of an IUPAC project. The water mass fraction was determined before and after the measurements. The viscosity and density of a sample with initial water content of 7a10-6 were represented by interpolating expressions with standard deviations of 0.4 % and 0.03 %, respectively. Differences between the experimental and calculated values are comparable with the expanded (k ) 2) uncertainties. For temperatures that overlap the temperature range (288 to 433) K at p ) 0.1 MPa, literature values of density differ by e ( 0.2 % while the reported viscosities differ by e ( 7 % from these empirical representations of the measurements. There are no values of the viscosity at p greater than 0.1 MPa reported in the literature to compare our results. At p greater than 0.1 MPa, the literature values for density reported by Gomes de Azevedo (J. Chem. Thermodyn. 2005, 37, 888-899) deviate from our smoothing equation by less than -0.2 % at temperatures and pressure that overlap ours. The electrical conductivity was determined on a sample with initial water mass fraction of 90a10-6. The results were represented within the expanded uncertainty by an empirical function against which the literature values differed by no more than ( 5 %.