Stabilization of hydroformylation catalysts based on phosphoramide ligands

A process for the hydroformylation of compounds which comprises, providing at least one compound with an ethylenically unsaturated double bond and reacting the at least one compound with carbon monoxide and hydrogen in at least one reaction zone in the presence of a catalytically active fluid which comprises a dissolved metal complex of a metal of transition group VIII of the Periodic Table of the Elements with at least one phosphoramidite compound as ligand, wherein the fluid is brought into contact with at least one base selected from trialkyl amines, dialkyaryl amines, alkyldiaryl amines, and triaryl amines, and

• wherein the phosphoramidite compound is selected from among compounds of the formulae I and II
• where
• R1 and R5 are each, independently of one another, pyrrole groups bound via the nitrogen atom to the phosphorus atom,
• R2, R3 and R4 are each, independently of one another, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, or R1 together with R2 and/or R4 together with R5 forms a divalent group containing at least one pyrrole group bound via the pyrrolic nitrogen atom to the phosphorus atom,
• Y is a divalent bridged group having from 2 to 20 bridge atoms between the flanking bonds,
• X1, X2, X3 and X4 are selected independently from among O, S, SiRαRβand NRγ, where Rα, Rβand Rγare each, independently of one another, hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, and
• a, b, c and d are each, independently of one another, 0 or 1,
• further comprising removing from the reaction zone a product mixture which is subjected to a fractionation to give a fraction consisting essentially of a hydroformylation product and a fraction comprising the catalytically active fluid in which the by-products of the hydroformylation which have boiling points higher than that of the hydroformylation product are present and the metal complex is dissolved, and recirculating the catalytically active fluid to the reaction zone.

A method of stabilizing a catalytically active fluid comprising a dissolved metal complex of a metal of transition group VIII of the Periodic Table of the Elements with at least one phosphoramidite compound as ligand in the hydroformylation of ethylenically unsaturated compounds, which comprises bringing the fluid into contact with at least one base selected from trialkyl amines, dialkyaryl amines, alkyldiaryl amines, triaryl amines, and bases immobilized on a solid phase, or a combination thereof,

• wherein the at least one phosphoramidite compound is selected from among compounds of the formulae I and II
• where
• R1 and R5 are each, independently of one another, pyrrole groups bound via the nitrogen atom to the phosphorus atom,
• R2, R3 and R4 are each, independently of one another, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, or R1 together with R2 and/or R4 together with R5 forms a divalent group containing at least one pyrrole group bound via the pyrrolic nitrogen atom to the phosphorus atom,
• Y is a divalent bridged group having from 2 to 20 bridge atoms between the flanking bonds,
• X1, X2, X3 and X4 are selected independently from among O, S, SiRαRβand NRγ, where Rα, Rβand Rγare each, independently of one another, hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, and
• a, b, c and d are each, independently of one another, 0 or 1.