Carbamazepine solubility in supercritical CO$_2$: a comprehensive study

In this paper we present our study of carbamazepine solubility in supercritical carbon dioxide. We have calculated the solubility values along two isochores corresponding to the CO$_2$ densities $ρ= 1.1ρ_{cr}(CO_2)$ and $ρ= 1.3ρ_{cr}(CO_2)$, where $ρ_{cr}(CO_2)$ is the critical density of CO$_2$, in the temperature range from $313$ to $383~K$, as well as along three isotherms at $T=318$, $328$ and $348~K$ by an approach based on the classical density functional theory. The solubility values were also obtained using in situ IR spectroscopy and molecular dynamics simulations along the mentioned isochores and isotherms, respectively. Because the density functional theory only takes into account the Lennard-Jones interactions, it can be expected to underestimate the solubility values when compared to the experimental ones. However, we have shown that the data calculated within the classical density functional theory qualitatively reproduce the solubility trends obtained by IR spectroscopy and molecular dynamics simulation. Moreover, the obtained position of the upper crossover pressure is in good agreement with the experimental literature results.