1070-4272/04/7706-1025 C 2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 6, 2004, pp. 1025!1027. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 6, 2004,
Original Russian Text Copyright C 2004 by Kalinina, Kopnina, Garkushin.
Fusibility Diagram of Cyclohexane!Tetradecane!Docosane
I. P. Kalinina, A. Yu. Kopnina, and I. K. Garkushin
Samara State Technical University, Samara, Russia
Received July 23, 2003; in the final form, April 2004
Abstract-The fusibility diagram of the cyclohexane3tetradecane3docosane ternary system was obtained by
low-temperature differential thermal analysis.
The functioning of heat exchangers is based on
heat accumulation by working fluids due to their heat
capacity . The working fluids in these devices
should ensure efficient heat accumulation and meet
some other requirements, in particular, they should
have low crystallization temperature .
Among organic substances meeting these require-
ments are n-alkanes, cyclic and aromatic hydrocar-
bons, and their mixtures .
It has also been found that cyclohexane , tetra-
decane , and their mixtures  are promising heat
accumulators and heat-carriers.
In this study we obtained the melting diagram of
the cyclohexane3tetradecane3docosane ternary system.
In our experiments, the heating and cooling curves
of organic mixtures were obtained on a low-tempera-
ture differential thermal analyzer (LDTA) equipped
with a Chromel3Copel thermocouple and a TZ 4620
flatbed XY recorder. One of the thermocouple junc-
tions was immersed in an organic mixture being tested
and the other was placed in a test tube filled with cal-
cined aluminum oxide powder as reference. The cold
thermocouple junction was placed in a Dewar flask
filled with water3ice mixture at 0oC. The thermal
electromotive force was amplified with a F116/1
photoamplifier. The sensitivity of recording of the
thermo-emf was controlled with an MCP-33 resistance
box. The baseline was controlled with an IRN-64
voltage source. The temperature was determined with
an accuracy of +0.2oC. In studies of phase transi-
tions, the organic mixtures were cooled and heated
in a TK-1 thermal chamber within the temperature
range from 340 to +60oC at a temperature variation
rate of 132 deg min
. The starting components
were weighed on a VLR-200 analytical balance with
an accuracy of up to 0.3 mg.
Cyclohexane, tetradecane, and docosane used in
our experiments were of pure grade. Their character-
istics coincided with reference data [9, 10]. The purity
of these reagents was checked by gas3liquid chro-
matography (a Tsvet-00 gas chromatograph; 50 m 0
0.25 mm and 25 m 0 0.25 mm capillary columns, vap-
orizer temperature 350oC; tetradecane and dodecane
were injected as toluene solutions).
The fusibility diagram of cyclohexane-tetradecane
binary system has an eutectic point (cyclohexane
Fig. 1. Phase diagram of the cyclohexane3tetradecane3
docosane system with projection of crystallization iso-
) Binary eutectic mixtures and (E)ternary
eutectic mixture. Sections: (I ) Docosane3(cyclohexane
33.7%, tetradecane 66.3%); (II ) Docosane3(cyclohexane
54.1%, tetradecane 45.9%); (III) Docosane3(cyclohexane
87.9%, tetradecane 12.1%); and (IV) Docosane3E