Manufacture of 2-ethylhexanol

The aldol condensation is used on a large scale in industry. Butanal, obtained by hydroformylation of propene, self-condenses with hot dilute sodium hydroxide; the aldol dehydrates under the same conditions to give 2-ethylhex-2-enal.

Catalytic hydrogenation reduces both the C=C double bond and the aldehyde, giving 2-ethylhexan-1-ol. Millions of tonnes are produced every year, mainly to make plasticizer esters for PVC, such as bis(2-ethylhexyl) phthalate.