(p, ρ, T) Properties of 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium hexafluorophosphate at T = (298.15 to 398.15) K and pressures up to p = 40 MPa

The (p, ρ, T) properties of 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] and 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6] at T = (298.15 to 398.15) K and pressures up to p = 40 MPa were measured using the vibration tube densimeter. Experimental (p, ρ, T) results are described by an equation of state. The isothermal compressibilities k · 106/MPa− 1 and thermal expansibilities α · 106/K− 1 have been calculated.