High-Pressure Densities and Derived Thermodynamic Properties of Imidazolium-Based Ionic Liquids
Year: 2006
Type: article
Abstract: This work addresses the experimental measurements of the pressure (0.10 < p /MPa < 10.0) and temperature (293.15 < T /K < 393.15) dependence of the density and derived thermodynamic properties, such as the isothermal compressibility, the isobaric expansivity, the thermal pressure coefficient, and the pressure dependence of the heat capacity of several imidazolium-based ionic liquids (ILs), namely, 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF 4 ]; 3-methyl-1-octylimidazolium tetrafluoroborate, [omim][BF 4 ]; 1-hexyl-3-methylimidazolium hexafluorophosphate, [hmim][PF 6 ]; 3-methyl-1-octylimidazolium hexafluorophosphate, [omim][PF 6 ]; 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, [bmmim][PF 6 ]; and 1-butyl-3-methylimidazolium trifluoromethansulfonate, [bmim][CF 3 SO 3 ]. These ILs were chosen to provide an understanding of the influence of the cation alkyl chain length, the number of cation substitutions, and the anion influence on the properties under study. The influence of water content in the density was also studied for the most hydrophobic IL used, [omim][PF 6 ]. A simple ideal-volume model was employed for the prediction of the imidazolium molar volumes at ambient conditions, which proved to agree well with the experimental results.
DOI: 10.1021/je060247x
Institutions: University of Aveiro, University of Coimbra
Language: English
Subfield: Physical and Theoretical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2161869452