Crotonic Acid

Title: Crotonic Acid
CAS Registry Number: 107-93-7
CAS Name: (2E)-2-Butenoic acid
Additional Names: b-methylacrylic acid; a-crotonic acid; solid crotonic acid; trans-crotonic acid
Molecular Formula: C4H6O2
Molecular Weight: 86.09
Percent Composition: C 55.81%, H 7.02%, O 37.17%
Literature References: Has been found in clay soil in Texas; formed during the dry distillation of wood. Obtained on a commercial scale exclusively by oxygen- or air-oxidation of crotonaldehyde: Kennedy, US 2413235 (1946 to Shawinigan Chem.); Leupold, PB report 70249 (1942); Matthews, B.I.O.S. report 758 (1946). Laboratory procedure using alkaline silver oxide: Young, J. Am. Chem. Soc. 54, 2498 (1932); from acetaldehyde and malonic acid in pyridine: v. Auwers, Ann. 432, 46 (1923); Backer, Bloemen, Rec. Trav. Chim. 45, 102 (1926); Florence, Bull. Soc. Chim. Fr. [4] 41, 440 (1927); Letch, Linstead, J. Chem. Soc. 1932, 454. Toxicity study: Smyth, Carpenter, J. Ind. Hyg. Toxicol. 26, 269 (1944). Review: W. Blau et al., in Ullmann's Encyclopedia of Industrial Chemistry vol. A8 (VCH, Weinheim, 5th ed., 1987) pp 83-89.
Properties: Monoclinic needles, prisms from water or ligroin. Corrosive and combustible solid. d415 1.018; d480 0.964. mp 71.6°. bp10 80.0°; bp20 93.0°; bp40 107.8°; bp60 116.7°; bp100 128.0°; bp200 146.0°; bp400 165.5°; bp760 185.0°. nD80 1.4228. pKa (25°) 4.817. Heat of combustion: 2.00 MJ/mol. Heat of fusion: 150.9 J/g. Soly in water (g/l) at 0°: 41.5; at 10°: 54.6; at 20°: 76.1; at 25°: 94; at 30°: 122; at 40°: 656. Soly in ethanol at 25°: 52.5% w/w; acetone: 53.0% w/w; toluene: 37.5% w/w. LD50 orally in rats: 1.0 g/kg (Smyth, Carpenter).
Melting point: mp 71.6°
Boiling point: bp10 80.0°; bp20 93.0°; bp40 107.8°; bp60 116.7°; bp100 128.0°; bp200 146.0°; bp400 165.5°; bp760 185.0°
pKa: pKa (25°) 4.817
Index of refraction: nD80 1.4228
Density: d415 1.018; d480 0.964
Toxicity data: LD50 orally in rats: 1.0 g/kg (Smyth, Carpenter)
Derivative Type: Methyl ester
Molecular Formula: C5H8O2
Molecular Weight: 100.12
Percent Composition: C 59.98%, H 8.05%, O 31.96%
Properties: Liq, bp 121°; d420 0.9444; nD20 1.4242.
Boiling point: bp 121°
Index of refraction: nD20 1.4242
Density: d420 0.9444
Derivative Type: Ethyl ester
Molecular Formula: C6H10O2
Molecular Weight: 114.14
Percent Composition: C 63.14%, H 8.83%, O 28.03%
Properties: Liq, bp 138°; d420 0.9175; nD20 1.4245.
Boiling point: bp 138°
Index of refraction: nD20 1.4245
Density: d420 0.9175
Derivative Type: Vinyl ester
Molecular Formula: C6H8O2
Molecular Weight: 112.13
Percent Composition: C 64.27%, H 7.19%, O 28.54%
Properties: Liq, bp 133°; d420 0.9410; nD20 1.450.
Boiling point: bp 133°
Index of refraction: nD20 1.450
Density: d420 0.9410
Use: In the manuf of copolymers with vinyl acetate used in lacquers and paper sizing; in the manuf of softening agents for synthetic rubber. In medicinal chemistry, e.g., in the manuf of DL-threonine, vitamin A.
Crotoxin Crotoxyphos Crotyl Alcohol CRP Crufomate

Crotonic acid
Skeletal formula
Ball-and-stick model
CAS number 107-93-7 N
PubChem 637090
ChemSpider 552744 YesY
DrugBank DB02074
ChEBI CHEBI:41131 YesY
Jmol-3D images Image 1
Image 2
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 [1]
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
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 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.[2]