vapor pressure (pa)
molality (mol/kg methano l)
vapor pressure (pa)
molality (mol/kg methanol)
Figure 1. Predicted vapor pressure of (a) LiCl and (b) LiBr nonaqueous electrolyte solutions as a function of salt molality.
The lines are calculated from equation of state with the parameters in Table 1, which were obtained by fitting the experi-
mental data at 298.15 K. The points represent the experimental data. For average absolute deviations (ADDs), see Table 2.
Table 2. The average absolute deviations (AADs) about the vapor pressure (P) for same regressed parameters of EOS in dif-
ferent temperature, from this work at 1 bar.
Salt σi (Å) εassoc/k (K) Molarity range (mol/kg) AAD%2 for P T (K)
2.802 308.15 LiCl 5.326 3215.46 0 - 4.580
2.733 308.15 LiBr 5.316 3137.97 0 - 4.345
1There are two parameter s for each salt . One is th e effecti ve averag e ion d iameter σi, and the other is the cation-methanol associating parameter: εassoc. The two
parameters are all salt dependent. 2cal exp
AAD , where NP is the number of the experimental points and f is the property of interest (P). The
superscript cal and exp indicate the value is from the calculation and experiment, respectively.
The predictive capability of EOS in this work can be
demonstrated by extrapolating the temperature to a little
higher value. For example, Figures 1(a) and (b) show the
predictive vapor pressures by using the parameters given
in Table 1, which are correlated from experimental vapor
pressures with a temperature of 298.15 K. Strikingly,
even up to 308.15 K, our EOS can still accurately repre-
sent the non-ideality of the nonaqueous electrolyte solu-
tions and the AADs are shown in Table 2.
A fundamental two-parameter equation of state for non-
aqueous electrolyte solutions is proposed by incorpora-
tion of low density expansion of nonprimitive mean
spherical approximation and statistical associating fluid
theory. The EOS has been tested for 9 nonaqueous alkali
halide solutions at ambient condition . The parameters are
obtained by fitting the vapor pressures and activities with
the average absolute deviation (AAD, see definition in
Table 1) of 1.120% and 0.106%. With the parameters
given by 298.15 K, the EOS can also well predict the
vapor pressure data of nonaqueous electrolyte solutions
at different temperature points and over the same mo-
lality range accurately.
 A. Anderko, P. Wang and M. Rafal, “Electrolyte Solutions:
From Thermodynamic and Transport Property Models to
the Simulation of Industrial Processes,” Fluid Phase
Equilibria, Vol. 194-197, 2002, pp. 123-142.
 J. R. Loehe and M. D. Donohue, “Recent Advances in
Modeling Thermodynamic Properties of Aqueous Strong
Electrolyte Systems,” AIChE Journal, Vol. 43, No. 1, 1997,
pp. 180-195. doi:10.1002/aic.690430121
 Y. Liu a nd S. Wata nair i, Chemical Engineering Progress,
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