New iron complex containing iron and phosphine ligand with specific organic group useful as catalyst for homogeneous-catalyzed conversion of reaction mixture e.g. containing hydrogen and carbon dioxide to form formic acid amine adduct

摘要

Iron complex containing iron and at least one phosphine ligand with at least 12C-organic group is new. An independent claim is included for the preparation of formic acid comprising (a) homogeneous-catalyzed conversion of a reaction mixture containing hydrogen, carbon dioxide, at least one polar solvent and a tertiary amine of formula (NR10R20R30) (A1) in the presence of the iron complex compound (as catalyst) in a hydrogenation reaction and optionally adding water to obtain a two-phase hydrogenation mixture comprising an upper phase containing the catalyst and (A1), and a lower phase containing the polar solvent, residues of the catalyst and formic acid-amine adduct of formula (NR10R20R30.x iHCOOH) (A2), (b) processing the obtained hydrogenation mixture, which comprises (b1) phases separation of the hydrogenation mixture, in a first phase separating device, into the upper phase and the lower phase or (b2) extracting the catalyst from the hydrogenation mixture, in the extraction unit, using an extraction agent containing (A1) to obtain a raffinate containing (A2) and the polar solvent and an extract containing (A1) and the catalyst or (b3) phase separating the hydrogenation mixture, in a first phase separator, into the upper phase and the lower phase and extracting the residues of the catalyst from the lower phase, in an extraction unit, with the extracting agent to give a raffinate containing (A2) and the polar solvent and an extract containing (A1) and the residues of the catalyst, (c) separating the polar solvent from the lower phase and from the raffinates (R2) in a first distillation apparatus to give a distillate containing the polar solvent, which is recycled into the hydrogenation reactor, and a two-phase sump mixture containing the upper phase containing (A1) and the lower phase containing (A2), (d) optionally phase separating the obtained sump mixture, in a second phase separator into the upper phase containing (A1) and the lower phase containing (A2) and (e) separating the sump mixture, respectively the lower phase containing (A2) in a thermal splitting unit to obtain the corresponding (A1), which is recycled into the hydrogenation reactor in step (a) and removing formic acid from the thermal unit. R10, R20, R30 : optionally branched, acyclic or cyclic, 1-16C-aliphatic, araliphatic or aryl group whose single carbon is optionally substituted by a hetero group, preferably O or N, where two or three of R10, R20 and R30 are optionally bonded to form four atoms containing chain; and xi : 0.4-5.