Solubility of p-Toluenesulfonamide in Pure and Modified Supercritical Carbon Dioxide

The experimental equilibrium solubilities of p-toluenesulfonamide (p-TSA) in supercritical carbon dioxide were measured at temperatures between (308.15 and 328.15) K and for pressures from (8.0 to 21.0) MPa using a dynamic flow method. The solubility ranged from a p-TSA mole fraction of 0.97.10(-5) (308.15 K, 8.0 MPa) to 5.12.10(-5) (328.15 K, 21.0 MPa). The effects of two cosolvents, ethanol and glycol, were investigated at a cosolvent mole concentration of 3.5 %. The results showed that the solubility was greatly enhanced by the presence of both the cosolvents, and ethanol exhibited a higher cosolvent effect. The Peng-Robinson EOS with van der Waals (VDW2) mixing rules was employed to calculate the density of the supercritical carbon dioxide (SC CO2) + ethanol mixture. The solubility data in the absence and presence of cosolvents were correlated by the Chrastil equation and the modified Mendez-Santiago and Teja equation, respectively. Both the correlations yielded satisfactory results, with average absolute relative deviation (AARD) values less than 6 %.