Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 1, pp. 12−16.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
A.K. Pyartman, V.A. Keskinov, P.V. Zaitsev, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 1, pp. 14−18.
OF SYSTEMS AND PROCESSES
Mutual Solubility of Components in the Systems
]–Decane–n-Octanol (n-Butanol, n-Decanol,
Cyclohexanol) at Different Temperatures
A. K. Pyartman, V. A. Keskinov, and P. V. Zaitsev
St. Petersburg State Technological Institute, St. Petersburg, Russia
Abstract—The influence of the reactant ratio on the specific surface area, total pore volume, and mean pore
diameter of mesoporous silicon dioxide prepared by the sol–gel method was examined. The optimal reactant ratio
for preparing the material with a high specific surface area was determimed.
Salts of quaternary ammonium bases (QABs) with
mineral acids (nitrates, chlorides), and also binary
extractive agents, salts of QABs with organic acids, are
used or have been suggested for use in separation and
puriﬁ cation of rare-earth metals and other elements [1–5].
As a rule, QAB salts are used as 10–40% solutions in
organic solvents. The choice of a solvent and concentration
of an extractive agent are of fundamental importance when
performing technological processes. Toluene is the most
frequently used in laboratory studies of physicochemical
parameters of extraction processes (extraction isotherms,
distribution coefﬁ cients, and element separation factors)
as a solvent in systems with QABs [4, 5]. However, use
of toluene in technological practice is complicated by its
low boiling and ﬂ ash points.
It is difﬁ cult to use hydrocarbon solvents (kerosene,
synthine, etc.) when working with QAB salts because
of the mutual solubility of the forming solvates in the
organic phase and hydrocarbon solvents. This leads to
stratification of the organic phase and formation of
a “third phase” in extraction systems. The organic phase
can be stabilized by choosing an appropriate modiﬁ er
and its concentration, e.g., by introduction of long-
chain aliphatic alcohols into the extraction system .
At the same time, there is no published evidence about
phase diagrams of ternary liquid systems constituted
by a rare-earth metal(III) solvate, hydrocarbon solvent,
and aliphatic alcohol in the range of homogeneous and
heterogeneous solutions at different temperatures, which
gives no way of evaluating the possible stratiﬁ cation of
the organic system and developing recommendations for
use of modiﬁ ers for practical purposes.
In this study, we examined phase diagrams of ternary
liquid systems (R
(n-butanol, n-decanol, cyclohexanol) (where R
trialkylbenzylammonium), which are of theoretical and
practical interest for the technology of rare-earth metals,
at temperatures of 298.15–333.15 K.
We used trialkylbenzylammonium chloride
NCl. QAB nitrate was
produced by triple or quadruple contact of QAB
chloride with a 6–8 M solution of ammonium nitrate.
] solvate was prepared by triple or
quadruple shaking of concentrated aqueous solutions
of neodymium nitrate (special purity grade) with
a QAB nitrate solution (100%). The concentration of
] solvate in the extract obtained was
0.724 ± 0.005 M, ρ
= 0.9710 ± 0.015 g cm
following solvents were used: decane (ρ
0.7263 g cm
), n-butane (ρ
= 0.8075 g cm
= 0.8221 g cm
), n-decanol (ρ
0.8300 g cm
), and cyclohexanol (ρ
= 0.9684 g cm
all of chemically pure grade. The optical density of
the aqueous solutions was measured with an SF-16
Binodal curves of the binary and ternary systems were
obtained using the visual-polythermic method [6–8]. The
formation conditions of heterogeneous solutions were
additionally monitored by the nephelometric technique
with a Kernco 966 R turbidimeter and a light ﬁ lter (λ =
850 nm). Consistent data were obtained in titration of
stratifying-phase binary systems with a third component
until homogeneous solutions were formed and in titration