Process for the hydroformylation of olefins in homogeneous phase

Process for the preparation of aldehydes by hydroformylation of olefins by means of synthesis gas over a transition metal complex catalyst, characterized in that within a

• first process step the olefins are reacted by means of an aqueous catalyst solution comprising a transition metal and ligands bonded thereto in the presence of a water-miscible solvent, the pressure, the temperature and the proportions of the solvent and the aqueous catalyst solution being controlled in such a way that the hydroformylation is carried out in a homogeneous single-phase reaction solution and within a
• second process step, by lowering the temperature and/or reducing the pressure, the homogeneous reaction solution obtained from the first reaction step is converted into a two-phase process solution and at least a part of the organic phase is separated from the aqueous phase;
• and,
• wherein further, the temperature and pressure are kept constant during the reaction and the single phase of the reaction solution is adjusted via the mass ratios of solvent to aqueous catalyst solution.