Title: Crotonaldehyde
CAS Registry Number: 4170-30-3
CAS Name: 2-Butenal
Additional Names: crotonic aldehyde; b-methylacrolein
Molecular Formula: C4H6O
Molecular Weight: 70.09
Percent Composition: C 68.54%, H 8.63%, O 22.83%
Line Formula: CH3CH=CHCHO
Literature References: Commercial product is a 95:5 mixture of trans:cis isomers. Prepn: v. Auwers, Eisenlohr, J. Prakt. Chem. 82, 115 (1910); Hibbert, J. Am. Chem. Soc. 37, 1759 (1915). Alternate synthesis: J. Smidt et al., Angew. Chem. 71, 176 (1959). Toxicity studies: H. F. Smyth, C. P. Carpenter, J. Ind. Hyg. Toxicol. 26, 269 (1944). Review of use in commercial processes: O. Horn, Ind. Eng. Chem. 51, 655-658 (1959). Reviews: J. E. Fernandez, T. W. G. Solomons, Chem. Rev. 62, 485-502 (1962); W. Blau et al., in Ullmann's Encyclopedia of Industrial Chemistry vol. A8 (VCH, Weinheim, 5th ed., 1987) pp 83-89. Review of carcinogenic potential: V. J. Feron et al., Mutat. Res. 259, 363-385 (1991); of role in DNA adduct formation: S. S. Hecht et al., Toxicology 166, 31-36 (2001).
Properties: Flammable liq. Lacrimator! mp -69°; bp 102.2°; d2020 0.853; nD17.3 1.4384. Flash pt when anhydr: 13°C (55°F) (open cup). Explosive limits in air 2.95-15.5% v/v. Vapor density 2.41 (air = 1). Heat capacity: 0.7 cal/g/°C; heat of vaporization: 123 cal/g. Dimerizes under strong acid conditions, slowly oxidizes to crotonic acid. Soly in water (g/100 g) at 20°: 18.1; at 5°: 19.2. Soly of water in crotonaldehyde (g/100 g) at 20°: 9.5; at 5°: 8.0. LD50 orally in rats: 0.3 g/kg (Smyth, Carpenter).
Melting point: mp -69°
Boiling point: bp 102.2°
Flash point: Flash pt when anhydr: 13°C (55°F) (open cup)
Index of refraction: nD17.3 1.4384
Density: d2020 0.853
Toxicity data: LD50 orally in rats: 0.3 g/kg (Smyth, Carpenter)
CAUTION: Potential symptoms of overexposure are irritation of eyes and respiratory system. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 80.
Use: Manuf of butyl alcohol, butyraldehyde, methoxybutyraldehyde, sorbic acid, maleic acid, crotonic acid, crotyl alcohol. In polymer chemistry: manuf of resins and polyvinyl acetals, solvent for polyvinyl chloride, rubber antioxidant, increases rubber strength with ketones. In prepn of insecticides and fertilizers. In production of flavors.
Crotonic Acid Crotoxin Crotoxyphos Crotyl Alcohol CRP

Skeletal formula
Ball-and-stick model
CAS number 4170-30-3 N, 123-73-9 (E) YesY, 15798-64-8 (Z) YesY
PubChem 447466
ChemSpider 394562 YesY
EC number 204-647-1
DrugBank DB04381
KEGG C19377 N
ChEBI CHEBI:41607 YesY
Jmol-3D images Image 1
Molecular formula C4H6O
Molar mass 70.09 g mol−1
Appearance colourless liquid
Odor pungent, suffocating odor
Density 0.846 g/cm3
Melting point −76.5 °C; −105.7 °F; 196.7 K
Boiling point 104.0 °C; 219.2 °F; 377.1 K
Solubility very soluble in ethanol, ethyl ether, acetone
soluble in chloroform
miscible in benzene
Refractive index (nD) 1.4362
R-phrases R11 R24/25 R26 R37/38 R41 R48/22 R50 R68
S-phrases S26 S28 S36/37/39 S45 S61
NFPA 704
NFPA 704.svg
Flash point 13 °C; 55 °F; 286 K
Autoignition temperature 207 °C; 405 °F; 480 K
Explosive limits 2.95-15.5%
Related compounds
Related alkenals Acrolein


 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

Crotonaldehyde is a chemical compound with the formula CH3CH=CHCHO. The compound is usually sold as a mixture of the E- and Z-isomers, which differ with respect to the relative position of the methyl and formyl groups. The E-isomer is more common (data given in Table is for the E-isomer). This lachrymatory liquid is moderately soluble in water and miscible in organic solvents. As an unsaturated aldehyde, crotonaldehyde is a versatile intermediate in organic synthesis. It occurs in a variety of foodstuffs, e.g. soybean oils.[2]