HOMOGENEOUS CATALYTIC HYDROGENATION OF FREE CARBOXYLIC ACIDS IN THE PRESENCE OF CLUSTER RUTHENIUM CARBONYL HYDRIDES

Article abstract of DOI:10.1016/S0022-328X(00)83702-X

Saturated monocarboxylic acids up to C6, several bicarboxylic acids and some of the corresponding anhydrides are hydrogenated in the homogeneous phase with H4Ru4(CO)8(PBu3)4 as catalyst to give the corresponding alcohols (present among the reaction products as esters) or lactones at 100-200 deg C under a pressures of 100-200 atm of hydrogen.Anhydrides react at temperatures lower than those needed for acids.Esters are not reduced.Only δ-valerolactone is hydrogenated to 1,5-pentanediol.Ruthenium carbonyl carboxylates have been recovered at the end of the reaction andappear to be catalytically active intermediates.