Continuous hydroformylation process with catalyst substitution

A continuous two-phase hydroformylation process for the production of aldehydes from olefins by means of carbon monoxide, hydrogen and a transition metal catalyst in a reaction zone, the transition metal being in the form of a water-soluble catalyst complex, characterised in that the process comprises the following steps once or several times:

• a) hydroformylating by reacting the olefins, carbon monoxide and hydrogen over a water-soluble transition metal catalyst comprising water-soluble organophosphorus ligands in the reaction zone;
• b) reducing the concentration of the olefins in the reaction zone by reducing the olefin feed to the reaction zone
• by greater than or equal to 50% and less than or equal to 100% based on the concentration of olefin in the reaction zone in process step a)
• and withdrawing at least a portion of the catalyst solution from the reaction system, wherein the catalyst solution withdrawal and olefin concentration reduction substeps may occur in this or reverse order, simultaneously or sequentially;
• c) feeding a solvent, a transition metal source and water-soluble organophosphorus ligands to the reaction system, wherein the feeding of the components may occur simultaneously or in any order sequentially;
• d) increasing the concentration of the olefins in the reaction zone by increasing the olefin feed to the reaction zone and hydroformylating by reacting the olefins with carbon monoxide and hydrogen.