Optical resolution
by diastereomeric salt formation based on gas
antisolvent fractionation is influenced by the chemical equilibrium
of the salt formation, the solubility, and the extraction of the compounds.
Selectivity, also known as resolution efficiency, is highly solvent-dependent
and is also affected by process parameters both in atmospheric and
supercritical processes. For the first time in the literature, a mathematical
model that employs all three Hansen parameters and operating parameters
is constructed to describe the selectivity of a gas antisolvent fractionation
process. The satisfying goodness of fit of the models suggests that
the outcome of the three subprocesses in the gas antisolvent fractionation
process (i.e., salt formation reaction, precipitation, and extraction)
can be described in a single model. A new formula for pressure and
temperature correction of the hydrogen-bonding component of the Hansen
parameter for non-ambient conditions for liquid methanol, ethanol,
and n-propanol is also suggested in this paper.