Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (4): 736-744.doi: 10.3866/PKU.WHXB201612293

• ARTICLE • Previous Articles     Next Articles

Density, Dynamic Viscosity and Electrical Conductivity of Two Hydrophobic Phosphonium Ionic Liquids

Qi-Ge ZHENG1,Hui LIU2,3,Quan XIA1,Qing-Shan LIU1,4,*(),Lin MOU1,*()   

  1. 1 School of Science, Shenyang Agricultural University, Shenyang 110866, P. R. China
    2 Shanghai Environmental Sanitation Engineering Design Institute, Shanghai 200232, P. R. China
    3 Shanghai Engineering Research Center of Contaminated Sites Remediation, Shanghai 200232, P. R. China
    4 College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, P. R. China
  • Received:2016-11-10 Published:2017-03-23
  • Contact: Qing-Shan LIU,Lin MOU;
  • Supported by:
    The project was supported by the Program for Liaoning Excellent Talents in University, China(LJQ2015099)


Two air and water stable hydrophobic phosphonium ionic liquids (ILs), tributyl-hexylphosphonium tetrafluoroborate ([P4446][BF4]) and tributyl-hexylphosphonium bis (trifluoromethylsulfonyl) imide ([P4446][NTf2]), were prepared by the traditional method. Their basic physico-chemical properties of density, dynamic viscosity, and electrical conductivity were measured in the temperature range of 283.15-353.15 K. The effect of the temperature and structure of the anion on the thermodynamic properties were discussed. The properties are compared with the cation structures changing of the phosphonium type ILs. The most important thermodynamic properties for their practical application, such as molecular volume, standard molar entropy, and lattice energy, were calculated from their density using empirical equations. The calculated values were compared with those of imdazolium and pyridinium type ILs. Molar electrical conductivity was determined from density and electrical conductivity. The applicability of the Vogel-Fulcher-Tamman (VFT) and Arrhenius equations to the fitting of the dynamic viscosity and electrical conductivity was validated. The activation of the electrical conductivity and dynamic viscosity were obtained from the final VFT equation. According to the Walden rule, the density, dynamic viscosity, and electrical conductivity were described by the Walden equation. The results are very important for academic studies as well as industrial applications of these ILs.

Key words: Ionic liquids, Density, Dynamic viscosity, Electrical conductivity, Walden rule