Physical properties of ionic liquids based on 1-alkyl-3-methylimidazolium cation and hexafluorophosphate as anion and temperature dependence

Densities p, speeds of sound u, and refractive indices n(D) were measured from T = (278.15 to 343.15) K. Dynamic viscosities eta were measured from T = (293.15 to 323.15) K. Surface tensions a were determined from T = (288.15 to 313.15) K. The physical properties data were measured at atmospheric pressure. The coefficients of thermal expansion alpha(P) of the ionic liquids were calculated from the experimental values of the density at several temperatures. The Parachor method was used to predict the densities, the refractive indices, and the surface tensions of the ionic liquids, and a comparison between experimental and predictive values was made at T = 298.15 K. (c) 2006 Elsevier Ltd. All rights reserved.