Crotonic acid

Crotonic acid
IUPAC name (E)-but-2-enoic acid
Other names trans-2-butenoic acid beta-methylacrylic acid 3-methylacrylic acid (E)-2-butenoic acid
Identifiers
CAS number	107-93-7 N
PubChem	637090
ChemSpider	552744 Y
DrugBank	DB02074
ChEBI	CHEBI:41131 Y
ChEMBL	CHEMBL1213528 Y
Jmol-3D images	Image 1 Image 2
SMILES C/C=C/C(O)=O O=C(O)/C=C/C
InChI InChI=1S/C4H6O2/c1-2-3-4(5)6/h2-3H,1H3,(H,5,6)/b3-2+ Y Key: LDHQCZJRKDOVOX-NSCUHMNNSA-N Y InChI=1/C4H6O2/c1-2-3-4(5)6/h2-3H,1H3,(H,5,6)/b3-2+ Key: LDHQCZJRKDOVOX-NSCUHMNNBH
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
Acidity (pKa)	4.69
Hazards
MSDS	SIRI.org
Related compounds
Other anions	crotonate
Related carboxylic acids	propionic acid acrylic acid butyric acid succinic acid malic acid tartaric acid fumaric acid pentanoic acid
Related compounds	butanol butyraldehyde crotonaldehyde 2-butanone
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox 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.

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

See also

• Crotyl
• Crotonaldehyde
• Crotyl alcohol
• Isocrotonic acid
• Methacrylic acid

References

 This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press.