Handbook of Solvents - George Wypych - ChemTech - Ventech!

Solubility of Selected Systems
and Influence of Solutes
5.1 EXPERIMENTAL METHODS OF EVALUATION AND CALCULATION
OF SOLUBILITY PARAMETERS OF POLYMERS AND SOLVENTS.
SOLUBILITY PARAMETERS DATA.
Valery Yu. Senichev, Vasiliy V. Tereshatov
Institute of Technical Chemistry
Ural Branch of Russian Academy of Sciences, Perm, Russia
5.1.1 EXPERIMENTAL EVALUATION OF SOLUBILITY PARAMETERS OF
LIQUIDS
The value of solubility parameter can be calculated from the evaporation enthalpy of liquid
at given temperature: 1
⎛ΔHp
−RT
⎞
δ= ⎜ ⎟
⎜ ⎟
⎝ V ⎠
12 /
[5.1.1]
where:
ΔHp latent heat of vaporization
V molar volume
5.1.1.1 Direct methods of evaluation of the evaporation enthalpy
For measurement of the evaporation enthalpy of volatile substances, adiabatic apparatuses
were developed. They require significant quantities of highly purified substances. The accuracy
is determined to a large degree by equipment design and precision of measurement.
Most calorimeters that measure a latent heat of vaporization work under isobaric conditions.
The measurement of a latent heat of vaporization requires monitoring heat input
into calorimeter and the amount of liquid evaporated during measurement time. 2-4
In calorimeters of a flowing type, 5-6 a liquid evaporates from a separate vessel of a calorimeter.
The vapors are directed into the second calorimeter where the thermal capacity of
gas is measured. The design of such calorimeters ensures a precise measurement of the
stream rate. Heaters and electrical controls permit control of heat flow with high precision
and highly sensitive thermocouples measure temperature of gas. There are no excessive
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