Chinese Journal of Chromatography ›› 2015, Vol. 33 ›› Issue (1): 58-64.DOI: 10.3724/SP.J.1123.2014.09018

Previous Articles     Next Articles

Determination of the thermodynamic parameters of ionic liquid 1-hexyl-3-methylimidazolium tetrafluoroborate by inverse gas chromatography

LI Xiaoping1,2, WANG Qiang1, LI Ling2, DING Yanping1,2   

  1. 1. Center for Physical and Chemical Analysis, Xinjiang University, Urumqi 830046, China;
    2. College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 830046, China
  • Received:2014-09-10 Revised:2014-10-28 Online:2015-01-08 Published:2014-12-26
  • Supported by:

    National Natural Science Foundation of China (Grant No. 21366029)

Abstract:

Inverse gas chromatography (IGC) was used to characterize the thermodynamic properties of ionic liquid (IL) 1-hexyl-3-methylimidazolium tetrafluoroborate ([HMIM]BF4) in the temperature range from 343.15 K to 373.15 K. A series of solvents with different chemical natures were used to determine the [HMIM]BF4-solvent interactions. The thermodynamic parameters including Flory-Huggins interaction parameter, partial molar heats of sorption, mixing and evaporation as well as the activity coefficient at infinite dilution were obtained to judge the interactions between [HMIM]BF4 and the selected solvents. In addition, the solubility parameters of [HMIM]BF4 at different temperatures were determined. The results showed that among the selected solvents, n-C6, n-C7, n-C8, n-C9, diethyl ether, tetrahydrofuran, benzene and cyclohexane were poor solvents for [HMIM]BF4, while toluene, m-xylene, methanol, ethanol, dichloromethane, tetrachloromethane, chloroform, acetone, ethyl acetate and methyl acetate were the favorite ones. The solubility parameter of [HMIM]BF4 at room temperature (298.15 K) was 23.70 (J·-3)0.5, which was obtained by the linear extrapolation method. The experiment proved that IGC is a simple and accurate method to obtain the thermodynamic properties of ionic liquids. The obtained thermodynamic parameters revealed the strength of the interactions between the selected solvents and the ionic liquid, which could be used as a reference to the further applications of the ionic liquid.

Key words: activity coefficient at infinite dilution, Flory-Huggins interaction parameter, inverse gas chromatography (IGC), ionic liquid (IL), solubility parameter

CLC Number: