Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 1, pp. 44−49.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © K.N. Semenov, D.G. Letenko, N.A. Charykov, V.A. Nikitin, M.Yu. Matuzenko, V.A. Keskinov, V.N. Postnov, A.A. Kopyrin, 2011,
published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84, No. 1, pp. 44−50.
INORGANIC SYNTHESIS AND INDUSTRIAL
Solubility and Some Properties of Aqueous Solutions
of Fullerenol-d and Composition of Crystal Hydrates
K. N. Semenov
, D. G. Letenko
, N. A. Charykov
, V. A. Nikitin
, M. Yu. Matuzenko
V. A. Keskinov
, V. N. Postnov
, and A. A. Kopyrin
St. Petersburg State University, St. Petersburg, Russia
Innovations at Leningrad Institutes and Enterprises, Private Company, St. Petersburg, Russia
Northwestern State Technical University, St. Petersburg, Russia
St. Petersburg State Technological Institute, St. Petersburg, Russia
Received March 4, 2010
Abstract—Method of isothermal saturation in ampules was used to study the solubility of fullerenol in distilled
water in the temperature range 20–80°C and to determine the composition of its equilibrium crystal hydrates.
The pycnometric technique was employed to examine how the density depends of the concentration of fullerenol
solutions and the average molar and partial molar volumes of the components in solution at 25°C was calculated.
The method of refractometry was used to study the dependence of the refractive index on the concentration of
fullerenol solutions and the speciﬁ c refraction of the solutions was calculated.
In , we developed a procedure for synthesis of
fullerenol and identiﬁ ed fullerenol-d by means of elec-
tronic absorption spectroscopy, IR spectroscopy, optical
microscopy, high-performance liquid chromatography,
and mass spectrometry. The goal of our present study
was to analyze aqueous solutions of fullerenol-d and de-
termine the composition of its crystal hydrates.
The method of isothermal saturation in ampules was
used to study the solubility of fullerenol-d in distilled
water at temperatures of 20–80°C. The saturation
conditions were the following: saturation duration τ =
120 min, saturation temperature maintained to within
±0.05°C, saturation in a shaker-thermostat at a shaking
frequency ω ≈ 80 s
, gravimetric analysis for the content
of fullerenol-d in an aqueous solution from a change in
mass in evaporation of an aqueous solution of fullerenol
to dryness at a temperature T ≈ 50 ± 2°C and pressure
p = 0.1 mm Hg. The experimental data obtained are
presented in Table 1 and Fig. 1.
It can be seen in Table 1 that the density of saturated
fullerenol-d solutions steadily grows with increasing
temperature, with a rather complex form, σ-shaped, of
(T) dependence. The run of this dependence (with
increasing saturation temperature) is simultaneously
affected by several factors: decrease in the solvent
(water) density, decrease in the solute (fullerenol-d)
density in any aggregative state (no published data
on the fullerenol density could be found, but the
very fact that the derivative ∂ρ
/∂T is negative is
beyond a reasonable doubt), increase in the solubility
of the denser fullerenol-d in the less dense water in
mass concentrations of saturated solutions (Fig. 1),
weakening of “weak” physical (and, in particular, Van
der Waals) interactions and simultaneous strengthening
of chemical interactions between molecules of the
solvent and solute.
It can be seen in Fig. 1 and Table 1, the solubility S
of fullerenol-d in water steadily grows with increasing
temperature on all concentration scales, with the plot of
the S(T) dependence also being σ-shaped. This fact is
not unexpected. Indeed, such an σ-shaped temperature
run of the solubility in the crystallization branch of light