New procedure for recycling homogeneous catalyst: propylene carbonate synthesis under supercritical CO2 conditions

Polyfluoroalkyl phosphonium iodides, Rf(3)RPI (Rf = C4F9C2H4, C6F13C2H4, C8F17C2H4; R = Me, Rf), catalyzed propylene carbonate synthesis from propylene oxide and carbon dioxide under supercritical CO2 conditions, where propylene carbonate was spontaneously separated out of the supercritical CO2 phase. The Rf(3)RPI catalyst could be recycled with maintaining a high CO2 pressure and temperature by separating the propylene carbonate from the bottom of the reactor followed by supplying propylene oxide and CO2 to the upper supercritical CO2 phase in which the Rf(3)RPI remained.