Determining the Solubility of Organic Compounds in Supercritical Carbon Dioxide Using Supercritical Fluid Chromatography Directly Interfaced to Supercritical Fluid Solubility Apparatus

The solubilities of benzoin and 3,3',4,4'-benzophenonetetracarboxylic dianhydride in supercritical fluid carbon dioxide have been measured using static supercritical fluid solubility apparatus directly interfaced to supercritical fluid chromatography (SFC). The method involves increasing the pressure of supercritical fluid carbon dioxide in controlled steps to produce a series of saturated sample solutions that are sequentially analyzed by online SFC. The system requires minimal manual sample manipulation stages and facilitates a self-validation check procedure. Solubility data for benzoin was determined at 308 and 318 K through the pressure range of 12-24 MPa using 2 MPa steps. Solubility data for 3,3',4,4'-benzophenonetetracarboxylic dianhydride was determined at 328 and 343 K through the pressure range 15-27.5 MPa using 2.5 MPa steps. The Mendez-Santiago and Teja model has been successfully applied to correlate all sets of experimental solubility data.