A thermodynamic study of polar and non-polar fluid mixtures : n-alkanenitrile and n-alkane systems.

This work consists of a thermodynamic study of liquid binary
mixtures of the type polar + non-polar. The polar components were
chosen to be members of the n-a1kanenitrile series of compounds
whereas the non-polar components are members of the n-alkane series.
The experimental part of the work includes:
a) the determination of upper critical solution temperatures of
binary mixtures of ethanenitri1e, propanenitri1e, and n-butanenitrile
with n-a1kanes in order to establish the limits of liquid-liquid
miscibility;
b) the measurement of the gas-liquid critical locus (pc_Tc_X)
for the six mixtures ethanenitrile + n-pentane to n-decane.
c) measurement of excess enthalpies of mixing at 298.15 K for
propanenitrile + n-pentane to n-heptane; n-butanenitrile + n-hexane,
+ n_octane, + n-dodecane, and + n-tetradecane.
d) and the measurement at 303.15 K of excess volumes of mixing for
propanenitri1e + n-pentane to n-octane; n-butanenitrile + n-pentane,
+ n-hexane, +n-octane, +n-decane, + n-dodecane, +n-tetradecane; and
n-hexanenitrile + n-hexane.
Although the experimental results are readily related to the
molecular size of the studied substances statistical theories of fluids
are used for a more formal interpretation.
The Scatchard - Hildebrand theory with a modification is used to
predict upper critical solution temperatures. The now widely used
van der Waals' one and two-fluid theories are used here to predict excess
enthalpies and volumes of mixing. The gas-liquid critical properties are
interpreted using a first-order theory together with the Van der Waa1s'
equation of state.
The predicted results show in each case satisfactory agreement
with experiment, furthermore, information is obtained on the relative
strength of the unlike interaction between the molecules of the mixtures
studied.