Viscosity of 1-Hexyl-3-methylimidazolium Hexafluorophosphate and 1-Octyl-3-methylimidazolium Hexafluorophosphate at High Pressure

The viscosities of 1-hexyl-3-methylimidazolium hexafluorophosphate ([hmim][PF 6 ]) and 1-octyl-3-methylimidazolium hexafluorophosphate ([omim][PF 6 ]) were measured with a rolling ball viscometer. The experimental temperatures were from (293.15 to 353.15) K and pressures were up to 20.0 MPa. The experimental values were correlated with a Vogel−Tamman−Fulcher (VTF) equation and a Tait-form equation.