Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (5): 1161-1167.doi: 10.3866/PKU.WHXB201602232

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Molar Surface Gibbs Free Energy of the Aqueous Solution of the Ionic Liquid [C2mim][OAc]

Jing TONG*(),Teng-Fei CHEN,Duo ZHANG,Lin-Fu WANG,Jian TONG,Jia-Zhen YANG   

  • Received:2015-11-27 Published:2016-05-07
  • Contact: Jing TONG
  • Supported by:
    the National Natural Science Foundation of China(21273003);Education Bureau of Liaoning Province, China(LJQ2013001);Liaoning BaiQianWan Talents Program, China(2013921029)


The values of the density and surface tension for an aqueous solution of the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate [C2mim][OAc] with various molalities were measured from 288.15 to 318.15 K with intervals of 5 K. Based on the thermodynamic model of the surface tension of a solution proposed by LI Yi-Gui et al., a new concept of the molar surface Gibbs free energy was proposed and a linear empirical equation between the molar surface Gibbs free energy and the concentration of the solution was established. Using this empirical equation, the molar surface Gibbs free energy of aqueous [C2mim][OAc] was estimated. Using the estimated molar surface Gibbs free energy, the surface tension of the solution was predicted. The predicted values and corresponding experimental values are in agreement. Thus, the molar surface Gibbs free energy may become a semi-empirical method to predict the properties of ILs and their solution parachor. From the molar Gibbs free energy, a new Eötvös equation was obtained and each parameter of the new equation has a clear physical meaning.

Key words: Ionic liquid, Aqueous [C2mim][OAc], Molar surface Gibbs free energy, Density, Surface tension


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