Crotonaldehyde Explained

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.

Production and reactivity

Crotonaldehyde is produced by the aldol condensation of acetaldehyde:

2 CH3CHO → CH3CH=CHCHO + H2O

Crotonaldehyde is a multifunctional molecule that exhibits diverse reactivity. It is a prochiral dienophile.[1] It is a Michael acceptor. Addition of methylmagnesium chloride produces 3-penten-2-ol.[2]

Polyurethane catalyst N,N,N′,N′-tetramethyl-1,4-butanediamine (also known as NIAX TMBDA) was obtained by hydrogenating the reaction product of crotonaldehyde and dimethylamine.[3]

Uses

It is a precursor to many fine chemicals. A prominent industrial example is the crossed aldol condensation with diethyl ketone to give trimethylcyclohexenone, this can be easily converted to trimethylhydroquinone, which is a precursor to the vitamin E.[4] Other derivatives include crotonic acid, 3-methoxybutanol and the food preservative Sorbic acid. Condensation with two equivalents of urea gives a pyrimidine derivative that is employed as a controlled-release fertilizer.

Safety

Crotonaldehyde is a potent irritant even at the ppm levels. It is not very toxic, with an of 174 mg/kg (rats, oral).

See also

External links

Notes and References

  1. Longley Jr., R. I.. . Emerson, W. S. . Blardinelli, A. J. . 3,4-Dihydro-2-methoxy-4-methyl-2H-pyran . Org. Synth.. 1954. 34. 29. 10.15227/orgsyn.034.0029.
  2. Coburn, E. R. . 3-Penten-2-ol . Org. Synth.. 1947. 27. 65. 10.15227/orgsyn.027.0065.
  3. Web site: Catalysts. 8 January 2011.
  4. Müller . Marc-André . Schäfer . Christian . Litta . Gilberto . Klünter . Anna-Maria . Traber . Maret G. . Wyss . Adrian . Ralla . Theo . Eggersdorfer . Manfred . Bonrath . Werner . 100 Years of Vitamin E: From Discovery to Commercialization . European Journal of Organic Chemistry . 6 December 2022 . 2022 . 45 . 10.1002/ejoc.202201190.