Solubilities of solids in supercritical fluids - I. New quasistatic experimental method for polycyclic aromatic hydrocarbons (PAHs)+pure fluids

A new quasistatic technique is presented to measure the solubilities of polycyclic aromatic hydrocarbons (PAHs) and other solids in supercritical fluids (SCFs). This technique eliminates potential clogging during expansion of the SCF solutions, a problem inherent with most dynamic SFE units. The pressure inside the equilibrium cell is dropped very slowly in a quasistatic mode by sampling the saturated SCF solutions at low flow rates (1-5 standard ml min^-1). The technique is shown to be accurate and extensive data can be obtained in a relatively quick manner. In addition, this technique may be readily used in conjunction with basically any analytical method. After proving the accuracy of the new method, solubility measurements of anthracene, phenanthrene, pyrene, and perylene in supercritical carbon dioxide and ethane have been made at 313, 323 and 333K and pressure range of 100-350 bar. The simulateneous solubilities of anthracene, phenanthrene and pyrene in mixtures were also measured at the above three temperatures and over the same pressure range.