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][BF4]; 3-methyl-1-octylimidazolium tetrafluoroborate, [omim][BF4]; 1-hexyl-3-methylimidazolium hexafluorophosphate, [hmim][PF6]; 3-methyl-1-octylimidazolium hexafluorophosphate, [omim][PF6]; 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, [bmmim][PF6]; and 1-butyl-3-methylimidazolium trifluoromethansulfonate, [bmim][CF3SO3]. 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][PF6]. 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.
keywords
PHYSICOCHEMICAL PROPERTIES; PHYSICAL-PROPERTIES; TEMPERATURE; WATER; DEPENDENCE; VISCOSITY; MIXTURES; CHLORIDE; EQUATION; SOLVENTS
subject category
Thermodynamics; Chemistry; Engineering
authors
Gardas, RL; Freire, MG; Carvalho, PJ; Marrucho, IM; Fonseca, IMA; Ferreira, AGM; Coutinho, JAP
our authors
Isabel Maria Delgado Jana Marrucho Ferreira
Full professor
João Manuel Costa Araújo Pereira Coutinho
Vice-Director
Mara Guadalupe Freire Martins
Research Coordinator