Pentanal
# Pentanal

Pentanal (also called valeraldehyde) is the organic compound with molecular formula $C_4H_9CHO.$ Classified as an alkyl aldehyde, it is a colorless volatile liquid. Its odor is described as fermented, bready, fruity, nutty, berry.

## Production

Pentanal is obtained by hydroformylation of butene. Also C4 mixtures can be used as starting material like the so-called raffinate II, which is produced by steam cracking and contains (Z)- and (E)-2-butene, 1-butene, butane and isobutane. The conversion to the product is accomplished with synthesis gas in the presence of a catalyst consisting of a rhodium-bisphosphite complex and a sterically hindered secondary amine with a selectivity toward pentanal of at least 90%.

## Use

Pentanal undergoes the reactions characteristic of any alkyl aldehyde, i.e., oxidations, condensations, and reductions. 2-Octanone, produced for use in the fragrance industry, is obtained by the condensation of acetone and pentanal, followed by hydrogenation of the alkene.

2-Propyl-2-heptenal is obtained from pentanal by aldol condensation, which is hydrogenated to the saturated branched 2-propylheptanol. This alcohol serves as a starting material for the PVC plasticizer di-2-propylheptyl phthalate (DPHP).

Pentanal (valeraldehyde) is oxidized to give valeric acid.

