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Crotonic acid

Crotonic acid
IUPAC name (E)-2-butenoic acid
Other names trans-2-butenoic acid
beta-methylacrylic acid
3-methylacrylic acid
CAS number 107-93-7
Molecular formula C4H6O2
Molar mass 86.09 g/mol
Density 1.02 g/cm3
Melting point

70-73 °C

Boiling point

185-189 °C

Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Crotonic acid, or trans-2-butenoic acid, is a short-chain unsaturated carboxylic acid, described by the formula CH3CH=CHCO2H. Crotonic acid is so named because it was erroneously thought to be a saponification product of croton oil. It crystallizes as needles from hot water.

Additional recommended knowledge

Isocrotonic acid (or quartenylic acid) is the cis analogue of crotonic acid. It is an oil, possessing a smell similar to that of brown sugar. It boils at 171.9°C, concomitant with conversion into crotonic acid. Isomerizaton is complete when the cis acid is heated to 170-180°C in a sealed tube.

Racemic threonine can be prepared from crotonic acid by alpha-functionalization using mercury(II) acetate.[1]

See also


  1. ^ Carter, H. E.; West, H. D. “dl-Threonine” Organic Syntheses, Collected Volume 3, p.813 (1955).

This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Crotonic_acid". A list of authors is available in Wikipedia.
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