Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 5, pp. 920−924.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
D.G. Cherkasov, K.K. Il’in, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 5, pp. 865−868.
Salting out of Butyric Acid from Aqueous Solutions
with Potassium Chloride
D. G. Cherkasov and K. K. Il’in
Chernyshevsky State University, Saratov, Russia
Received October 17, 2008
Abstract—Visual-polythermic method was used to study the solubility of the components and critical phenomena
in the ternary system constituted by potassium chloride, water, and butyric acid in the temperature range 5−80°C.
The temperature dependence of the solution compositions corresponding to the critical solubility points was
determined. The isothermal solubility diagrams of the system were constructed. The distribution coefficients of
butyric acid at 5, 25, 50, and 80°C were calculated.
Butyric acid and its aqueous solutions are widely
used in treatment of rare-earth elements to remove
alkaline-earth metals (magnesium, calcium, strontium,
and barium), in decalcification of leather, perfume
manufacture, synthesis of aromatic principles in food
industry, and in production of plasticizers for lacquers
and emulsiﬁ ers .
The introduction of the third substance, for example,
salting out agent, into the binary homogeneous system
constituted by water and butyric acid considerably
changes its phase behavior [2, 3]. To our knowledge, only
one study concerning the effect of sodium chloride on the
water-butyric acid binary system at 25°C is available .
The introduction of the salt caused system to separate onto
two liquid phases. In , the solubility of the components
in the ternary system was determined by the method of
isothermal titration, the compositions of coexisting liquid
phases in the stratiﬁ cation region were found by analytical
method, the isothermal phase diagram of the system was
constructed, and the coordinates of the critical point in
the stratiﬁ cation region were found approximately. It was
pointed out that a homogeneous mixture of water and
butyric acid becomes stratiﬁ ed in the presence of even
minor amounts of the salt.
Thus, data on the effect exerted by salts on the water-
butyric acid binary system are lacking from the literature
and the temperature dependence of phase behavior in
the ternary system constituted by salt, water, and butyric
acid is unknown.
In the present study, the phase equilibria and critical
phenomena in the ternary system constituted by potassium
chloride, water, and butyric acid in the temperature range
5−80°C were analyzed in order to reveal the dependence
of its phase behavior on the salting out ability and
temperature. The above system has not been studied
The solvents (water and butyric acid of chemical purity
grade) used in the study were thoroughly purified .
A potassium chloride preparation of chemical purity grade
was dried as described in . Preparations of butyric
acid and salt were placed in the exciccators protected
from a direct exposure to light and kept over calcined
The phase equilibria in the mixtures of the components
of the KCl−H
ternary system were studied in
glass ampoules under vapor pressure using the visual-
polythermic method .
The solution compositions corresponding to the
critical solubility points were found by the method of
phase volume ratio . The necessary temperature was
maintained constant to within ±0.1°C with a Lauda A-