Hydrogenation of an α,β-unsaturated aldehyde catalyzed with ruthenium complexes with different fluorinated phosphine compounds in supercritical carbon dioxide and conventional organic solvents

The effectiveness of a series of Ru complexes with fluorinated phosphine compounds has been studied for cinnamaldehyde (CAL) hydrogenation in supercritical carbon dioxide (scCO2) and conventional organic solvents. The Ru complexes with fluorinated phosphine compounds are more active for CAL hydrogenation in scCO2 medium as well as in conventional solvents compared with that with an unfluorinated phosphine, triphenylphosphine. 1,2-bis[bis(pentafluorophenylphosphino)ethane was found to be the best among the six phosphine compounds examined for both scCO2 and organic solvents. scCO2 is a more effective, green reaction medium for homogeneous CAL hydrogenation compared with conventional organic solvents.