Butyraldehyde, also known as butanal, is an organic compound with the formula CH3(CH2)2CHO. This compound is the aldehyde derivative of butane. It is a colorless flammable liquid with an unpleasant smell. It is miscible with most organic solvents.
Production
Butyraldehyde is produced almost exclusively by the
hydroformylation of
propylene:
- CH3CH=CH2 + H2 + CO → CH3CH2CH2CHO
Traditionally, hydroformylation was catalyzed by
cobalt carbonyl but
rhodium complexes are more common. The dominant technology involves the use of rhodium catalysts derived from the water-soluble ligand
tppts. An aqueous solution of the rhodium catalyst converts the propylene to the aldehyde, which forms a lighter (less dense) immiscible phase. About 6 billion kilograms are produced annually in this manner. Butyraldehyde can be produced by the catalytic
dehydrogenation of
N-Butanol. At one time, it was produced industrially by the catalytic
hydrogenation of
crotonaldehyde, which is derived from
acetaldehyde.
Reactions and uses
Butyraldehyde undergoes reactions typical of alkyl
, and these define many of the uses of this compound. Important reactions include
hydrogenation to the alcohol,
oxidation to the acid, and base-catalyzed condensation. In the presence of a base, two equivalents of butyraldehyde undergoe aldol condensation to give 2-ethylhexenal. This unsaturated aldehyde is then partially
hydrogenation to form 2-ethylhexanal, a precursor to
such as bis(2-ethylhexyl) phthalate.
Butyraldehyde is a component in the two-step synthesis of trimethylolpropane, which is used for the production of Alkyd.
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