Surface Tension and Density of Pure Ionic Liquids and Some Binary Mixtures with 1-Propanol and 1-Butanol

Abstract

The pendant drop method has been used for measuring the surface tension of the pure ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, methyltrioctylammonium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium ethylsulfate, and 1-butyl-3-methylimidazolium octylsulfate in the range of (278 to 333) K. In addition, densities and thermal expansion coefficients of these ionic liquids are presented. The values of surface tension lie between (25 and 48) mN·m−1 and decrease with temperature. Surface tension σ of the mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide + 1-propanol and + 1-butanol have also been determined as a function of the mole fraction at 298 K. Since the pendant drop method requires precise density measurements of the mixtures, densities were also measured.

Low‐Viscosity Paramagnetic Ionic Liquids with Doubly Charged [Co(NCS)4]2− Ions

“…In contrast however, this value is quite low in comparison with (BMIm) [FeCl 4 ] (D vap H = 170(1) kJ mol À1 ) or other dicationic ILs. [21] This result is in accordance with the low viscosity of compound 1, indicating weak intermolecular interactions. To correlate physicochemical properties, which basically depend on structures and energies of interactions (such as viscosity, selfdiffusion coefficient, molar mass), good correlations are known for conventional solvents.…”

“…[21] The molar enthalpy of vaporization D vap H of 1 was determined by isothermal thermogravimetrical measurements. Even though the vapor pressure is a crucial property of liquids with respect to possible technical applications, to date only a few values of the enthalpy of vaporization of ILs are known owing to the very low vapor pressure and the challenges that therefore arise in determining these values.…”

Effect of Nitrile-Functionalization of Imidazolium-Based Ionic Liquids on Their Transport Properties, Both Pure and Mixed with Lithium Salts

“…The density of the pure [C 1 C 4 Im][NTf 2 ] was already measured by other groups [24][25][26][27][28]. The values reported here are slightly lower (average relative deviation between 0.15 and 0.3 %) than most of the data presented in the literature.…”

Thermophysical Properties of 1-Butyl-3-Methylimidazolium Bis(trifluoromethylsulfonyl)imide at High Temperatures and Pressures

“…The relation between these anomalies and thermal history after crystallization was described. Wandschneider et al (2008) used the pendant drop method for measuring the surface tension σ/n·m -1 of [BMIM][NTf 2 ] at T = (292.88 to 391.28) K. The required density ρ/kg⋅m -3 data of IL were obtained using a vibrating tube densimeter (Anton Paar DMA 512 P), which was calibrated at each temperature using liquid water, dry air, and n-hexane as calibration substances. The uncertainty of the density data was estimated to be ±1·10 -4 g·cm -3…”