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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.

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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