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(C6F5)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 recirculation view cell apparatus coupled to a high-performance liquid chromatograph 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)phosphine up to 12.0 MPa and 0.246 mol/L, tris(p-fluorophenyl)phosphine up to 18.9 MPa and 0.468 mol/L, and tris(p-trifluoromethylphenyl)phosphine up to 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.