Process for the recovery of phosphorus-containing ligands, metal complexes with phosphine

Disclosed is a method for recovering from phosphine ligands in a homogeneously catalyzed reactions, transition metal complexes used which contain phosphine ligands, in which a) contacting the remaining after completion of a reaction catalyzed homogeneous reaction mixture with an oxidizing agent, b) then extracted the reaction mixture to separate the resulting Ubergangsoxids with a poorly miscible with the reaction mixture organic solvent and then c) the oxidized phosphine ligand isolated from the reaction mixture separated from the organic solvent.