Solubilities of Anthraquinones in Pressurized Solvents

BARRERA VAZQUEZ, MARÍA FERNANDA; BOTTINI, SUSANA; MARTINI, RAQUEL; ANDREATTA, ALFONSINA

Viña del mar

Conferencia; IV Iberamerican Conference on Supercritical Fluids. Prosciba 2016; 2016

Universidad Católica de Chile

Anthraquinones (AQs) are an important category of secondary metabolites present in various vegetable species. They are highly bioactive compounds, potentially useful for therapeutic applications, as antiviral, anti-bacterial and anti-cancer agents. Extraction processes using pressurized hot water and supercritical fluids offer an environmentally friendly alternative to traditional extracting and purifying methods applied to anthraquinone-containing plants. Knowledge on high-pressure phase equilibria of AQs + solvent mixtures is required to evaluate the potentiality of these processes. The need is for both, experimental data and thermodynamic models that are able to predict phase boundaries at different process conditions.In this work, the solubility of 1,4-dihydroxy-9,10-anthraquinone (quinizarine) in pressurized hot water and in supercritical carbon dioxide have been measured, using a simple and reliable dynamic method. For the binary quinizarine + H2O, the measurements covered a range of 398-473K and pressures close to 60 bar, while the quinizarine + CO2 system was measured at 308-348K and 100-400 bar.The group-contribution with association equation of state GCA-EOS was used to calculate solid-liquid and solid-fluid equilibria of binary mixtures of AQs with pressurized hot water and supercritical carbon dioxide and ethane. The calculated solubilites were compared to the experimental data measured in this work and those available in the literature for different antraquinones. The results showed the capability of the GCA-EOS equation to reproduce the phase equilibrium conditions of these systems.