1070-4272/02/7512-1925 $27.00 C 2002 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 75, No. 12, 2002, pp. 1925!1930. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 12, 2002,
Original Russian Text Copyright + 2002 by Ya. Naziev, Shakhverdiev, Gasanov, Dzh. Naziev.
OF SYSTEMS AND PROCESSES
P!V!T Dependence for Methanol Solutions
with Aromatic Hydrocarbons
Ya. M. Naziev, A. N. Shakhverdiev, V. G. Gasanov, and Dzh. Ya. Naziev
Azerbaijani Technical University, Baku, Azerbaijan
Azerbaijani State Academy of Oil, Baku, Azerbaijan
Received January 24, 2002
Abstract-The density of binary solutions methanol3para-xylene, methanol3ortho-xylene, and methanol3
meta-xylene was measured on an installation for hydrostatic weighing in relation to pressure, temperature,
and concentration. The experimental results are generalized using the equation of state.
Density is one of the most important physicochem-
ical characteristics related to the structure of a sub-
stance. The thermal properties of binary solutions of
methanol with aromatic hydrocarbons attract attention
of not only researchers in various fields of science,
but also engineers and designers in chemical, petro-
chemical, food, medical, and other industries. Study-
ing the properties of these solutions is also of scien-
tific interest for modernization of the theory of so-
An analysis of published data demonstrated that
there is sufficient body of data on density of pure
methanol and para-, meta-, and ortho-xylenes [1, 2],
whereas for methanol3para-xylene, methanol3ortho-
xylene, and methanol3meta-xylene solutions no data
of this kind are available in the literature.
In this context, we studied experimentally the P!
V!T dependence for these binary solutions in liquid
phase at temperatures of 2903500 K in the pressure
range 0.1358.9 MPa at 25 wt % intervals.
The choice of the given systems is governed by
the fact that the molecules of these substances contain
even numbers of carbon atoms, have about the same
ring structure, and, as shown by optical studies, these
hydrocarbons and their solutions are characterized by
intermolecular interaction varying with temperature,
pressure, and concentration.
We chose the method of hydrostatic weighing for
the experimental study. The piezometer used to de-
termine the density of liquids operates on the principle
that a solid submerged in a liquid experiences a buoy-
ancy force, which depends on the density of a medium
under study. Having determined the buoyancy force
acting on the float (whose volume is known) and the
mass of the float in empty space and in liquid, we can
calculate the density of the medium [3, 4].
This method was proposed in [5, 6]. The exper-
imental setup for measuring the P!V!T dependence
for liquids is based on a variation of the hydrostatic
weighing technique, which ensures high measurement
accuracy and is comparatively simple in preparing
for experiment and carrying out the procedure itself.
In order to improve the sensitivity and to use heavier
floats, the integrated circuit in the electronic servo
system was replaced [7, 8].
Based on analysis of calibration data for elements
of the suspension system, we obtained the follow-
ing volumes and masses of the suspension system:
m = 8.9650 g, V
= 3.1212 cm
= 0.2647 cm
= 3.1212 cm
, where subscript [f] corresponds to
the float; [c] to core; [t] to thread. The measurement
was done with maximum error of 0.1% in the entire
range of parameters of state.
The purity of the substances studied was deter-
mined using a Tsvet chromatograph to be 99.87%
for methanol and 99.96399.98 wt % for para-, meta-,
Having determined on VLA-200g-M analytical
balance to within 10
kg the mass of each component
necessary for obtaining the required concentration of
mixtures, we mixed the components in quartz vessels.