| Crotonic acid | |
|---|---|
 |
|
| IUPAC name | (E)-2-butenoic acid |
| Other names | trans-2-butenoic acid beta-methylacrylic acid 3-methylacrylic acid |
| Identifiers | |
| CAS number | |
| SMILES | C/C=C/C(O)=O |
| Properties | |
| 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
References
- ^ Carter, H. E.; West, H. D. “dl-Threonine” Organic Syntheses, Collected Volume 3, p.813 (1955). http://www.orgsyn.org/orgsyn/pdfs/CV3P0813.pdf.
This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.
