Solubilities of benzoin propyl 4-hydroxybenzoate and mandelic acid in supercritical carbon dioxide

A semi-flow type apparatus was used to measure the equilibrium solubilities of benzoin , propyl 4-hydroxybenzoate,
and mandelic acid in supercritical carbon dioxide at 308.15, 318.15, and 328.15K over the pressure range
from 9 to 24MPa. New equilibrium data of solid solubility in supercritical carbon dioxide are presented. The
approach to solid–fluid phase equilibrium is examined based on a plug flow fluid–solid mass transfer model.
The Soave–Redlich–Kwong and the Peng–Robinson equations of state (EOS), with the van der Waals and the
Huron–Vidal type mixing rules were used to correlate the experimental data. The solid solubility data were also
correlated with density based semi-empirical equations of Chrastil, and Santiago–Teja. It is shown that these solid
solubility data are correlated with reasonably good accuracy using optimally fitted parameters.