Solubility of stearic acid in supercritical CO2-acetonitrile mixtures

The solubility of stearic acid in supercritical CO2 with acetonitrile (CH3C N) cosolvent was measured at 318.15 K in the pressure range from 9.5 to 16. 5 MPa, and the cosolvent concentration ranges from 0.0 to 5.5 mol%. The sol ubility increases with acetonitrile concentration and pressure, and it also increases with the apparent density of CO2 d(1)(moles of CO2 in per liter of fluid) at higher cosolvent concentrations. At lower d(1), however, the s olubility of the acid at lower acetonitrile concentrations is lower than th at in pure CO2 provided that d(1) is fixed, which is discussed qualitativel y based on the clustering of the components in the system.