Crotonaldehyde

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]

Additional recommended knowledge

Daily Visual Balance Check

Essential Laboratory Skills Guide

What is the Correct Way to Check Repeatability in Balances?

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]

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.

See also

• Crotyl
• Crotonic acid
• Crotyl alcohol
• Methacrolein

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. 

• Merck Index, 11th Edition, 2599
• Hazardous Substance Fact Sheet