Crotonaldehyde

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Crotonaldehyde
IUPAC name (E)-2-Butenal
Other names Crotonaldehyde
crotoinic aldehyde
β-Methacrolein
Molecular formula C4H6O
Identifiers
CAS number [123-73-9]
SMILES O=C/C=C/C
Properties
Molar mass 70.09 g/mol
Density 0.846 g/cm3
Melting point

-76.5 °C
Boiling point

104.0 °C
Solubility in water organic solvents
Refractive index (nD) 1.4362
Hazards
NFPA 704
3
4
2
 
R-phrases 11-24/25-26-37/38-41-48/22-50-68
S-phrases 26-28-36/37/39-45-61
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and 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.[1]

Contents

[edit] Production and uses

Crotonaldehyde is produced by the aldol condensation of acetaldehyde:

2 CH3CHO → CH3CH=CHCHO + H2O

Its main application is as a precursor to fine chemicals. Sorbic acid, a food preservative, and trimethylhydroquinone, a precursor to the vitamin E, are prepared from crotonaldehyde. Other derivatives include crotonic acid and 3-methoxybutanol.[1]

Crotonaldehyde is a multifunctional molecule that exhibits diverse reactivity. It is an excellent prochiral dienophile.[2] It is a Michael acceptor. Addition of methylmagnesium chloride affords 3-penten-2-ol.[3]

[edit] Safety

Crotonaldehyde is an irritant. It is listed as an "extremely hazardous substance" as defined by the U.S. Emergency Planning and Community Right-to-Know Act. It occurs widely in nature.

[edit] See also

[edit] References

  1. ^ a b R. P. Schulz, J. Blumenstein, C. Kohlpaintner "Crotonaldehyde and Crotonic Acid" Ullmann's Encyclopedia of Chemical Technology Wiley-VCH, Weinheim: 2005. DOI: 10.1002/14356007.a08 083
  2. ^ Longley, Jr., R. I..; Emerson, W. S.; Blardinelli, A. J. (1963). "3,4-Dihydro-2-methoxy-4-methyl-2H-pyran". Org. Synth.; Coll. Vol. 4: 311. 
  3. ^ Coburn, E. R. (1955). "3-Penten-2-ol". Org. Synth.; Coll. Vol. 3: 696.