1070-4272/01/7405-0822$25.00C2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 5, 2001, pp. 822!829. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 5,
2001, pp. 797!804.
Original Russian Text Copyright C 2001 by Totchasov, Nikiforov, Luk’yanchikova, Al’per.
AND POLYMERIC MATERIALS
Comparative Analysis of the Methods for Calculating
the Viscosity of Binary Nonelectrolyte Mixtures
E. D. Totchasov, M. Yu. Nikiforov, I. A. Luk’yanchikova, and G. A. Al’per
Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russia
Received April 8, 1999; in final form, June 2000
Abstract-The results of calculating the viscosity of binary nonelectrolyte systems by methods obviating
fitting parameters were compared. A method was proposed for calculating the viscosity of n-alkanol3n-alkane
solutions with account of the molecular association by the free-volume theory accurately to within 7.9%.
Studies of the concentration dependence of the
viscosity of liquid solutions have recently generated
much interest in the context of many practical prob-
lems . The viscosity as a physicochemical prop-
erty is very sensitive to intermolecular interactions.
For example, experimental data in [5, 6] suggest that
in the water3dimethylformamide (DMF) system the
maximal deviations from additivity make 2% for
density, 9% for heat capacity, and 24% for adiabatic
compressiblity against 197% for viscosity. This trend
is observed for other nonelectrolyte systems as well.
Development of methods for calculating the viscosity
of multicomponent liquid systems is in the scope of
the theory of solutions .
By now, the theory of viscosity of liquids has by
no means been developed to completion, and the vis-
cosity of solutions can be calculated practically in
terms of semi-theoretical concepts like the Eyring
theory , the free-volume theory , or their com-
bination . Also, caclulations can be made by for-
mulas utilizing fitting parameters to be determined us-
ing one or several preset experimental points .
In this work we carry out a comparative analysis of
selected methods for calculating the viscosity of
binary nonelectrolyte mixtures obviating fitting pa-
The deviation of the physicochemical properties of
mixtures from their additive values is the greatest in
the vicinity of the equimolar composition. This makes
reasonable analysis of the predictive power of the cal-
culational methods either for the composition corre-
sponding to the maximal deviation from additivity, or
for all the systems at the equimolar composition. In
this work, we chose the latter option.
In , we calculated the viscosity of nonelectro-
lyte solutions in terms of the Eyring concept of the
activation nature of viscous flow. The viscosity of
organic liquids and their mixtures is adequately de-
scribed by the formula
h = A exp(DH
is the activation enthaply of viscous flow.
Following the Eyring’s assumption that the activa-
tion enthalpy is a fraction of the cohesion energy E
we obtained eventually for equimolar mixtures [X
= 0.5 mole fraction (m.f.)] the relation 
Dlnh = 3H
0 [(0.5 + j
+ (0.5 + j
+ RT is
the enthalpy of vaporization of the components A and
B, respectively; Dlnh =lnh30.5lnh
h is the dynamic viscosity of the equimolar solution;
are the dynamic viscosities of the com-
ponents A and B, respectively; and j
volume fractions of these components, respectively.
Herefrom, the viscosities of the pure components
are assumed to be known. The DH
values for the pure components were taken from ,
, from reference books [18, 19]. The experi-
mental values of the viscous flow activation energy
for solution DH
were determined from the depen-
=1/T, i.e, from the experimental h