Continuous process for the production of aldehydes by hydroformylation of olefins

In a continuous hydroformylation process for the production of an aldehyde by hydroformylation of an olefin which comprises:

• providing a hydroformylation zone containing a charge of a liquid reaction medium having dissolved therein a complex rhodium hydroformylation catalyst comprising rhodium in complex combination with carbon monoxide and with a cyclic phosphite having a phosphorus atom linked to three oxygen atoms at least two of which form together with the phosphorus atom part of a ring;
• supplying said olefin to the hydroformylation zone;
• maintaining in the hydroformylation zone a temperature in the range of from about 40.degree. C. to about 160.degree. C. and a pressure in the range of from about 4 bar to about 75 bar;
• supplying make-up hydrogen and carbon monoxide to the hydroformylation zone;
• and
• recovering from the liquid hydroformylation medium a hydroformylation product comprising at least one aldehyde selected from the group consisting of linear aldehydes and non-linear aldehydes,
• the improvement comprising providing in the liquid reaction medium a ligand stabilising amount of tertiary amine dissolved therein thereby to increase the stability of the cyclic phosphite ligand in the liquid reaction medium under the hydroformylation conditions used.