Solubility of triphenylphosphine, tris(p-fluorophenyl)phosphine, tris(pentafluorophenyl)phosphine, and tris(p-trifluoromethylphenyl)phosphine in liquid and supercritical carbon dioxide

The solubility of the solid substances triphenylphosphine P(C6H5)(3), tris( p-fluorophenyl)phosphine P(C6H4F)(3), tris(pentafluorophenyl)phosphine P(C6 F5)(3), and tris(p-trifluoromethylphenyl)phosphine P[4-(CF3)C6H4](3) in CO2 was measured as a function of pressure at 300.0 K, 310.0 K, 320.0 K, and, in the case of triphenylphosphine, at 330.0 K. For this purpose, a new reci rculation view cell apparatus coupled to a high-performance liquid chromato graph was constructed. The solubility S of triphenylphosphine was measured up to 30.3 MPa and up to a maximum of 0.119 mol/L, tris(pentafluorophenyl)p hosphine up to 12.0 MPa and 0.246 mol/L, tris(p-fluorophenyl)phosphine up t o 18.9 MPa and 0.468 mol/L, and tris(p-trifluoromethylphenyl)phosphine up t o 12.0 MPa and 0.470 mol/L. The increasing degree of fluorination in these four substances led to an increase of their solubility in carbon dioxide.