The solubilities of xanthone and xanthene in supercritical carbon dioxide: Structure effect

The equilibrium solubility of the two pesticides - xanthone and xanthene - in supercritical carbon dioxide was determined with a flow-type method. Measurements were performed at pressures ranging from 80 to 300 bar and temperatures from 308.15 to 328.15 K. The results show that xanthene was much more soluble in supercritical carbon dioxide than xanthone with its solubility being over 10-fold higher than that of xanthone due to their different volatility related to their chemical structures. The determined solubility data were well correlated by the Peng-Robinson equation of state and the empirical density-based Chrastil model with the average absolute relative deviation (AARD) less than 11.5% for two solutes investigated.