3. Hydroformylation of propene

The first cobalt-catalyzed olefin hydroformylation unit was commissioned in 1945 [7] . From 1945 to 1975, yields improved little; for example, for the cobalt process with propene [8] :

• aldehyde selectivity C ₄ : 86 % of which :

• n-butanal selectivity: 70% ;

• isobutanal selectivity: 16%.

Isobutanal was produced in excess of demand. The possibility of using rhodium catalysts to save propene and simplify the process had been investigated in the early 1970s (yield of butanal expected to exceed 90%, i.e. a 20% yield improvement over the cobalt process) [9]...