Chemistry: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. 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]
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.[2] It is a Michael acceptor. Addition of methylmagnesium chloride produces 3-penten-2-ol.[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.[5] 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. [1]
Trans-crotonaldehyde is commonly used to determine the effective Lewis acidity of Lewis acids,[6] determined from the change in 1H NMR shift of the crotonaldehyde handle on binding to a Lewis acid. Limitations of the method include secondary interactions to the 1H NMR handle obscuring the true effect of the Lewis acid, and weak donor strengths of trans-crotonaldehyde resulting in incomplete Lewis acid-base adduct formation.[7]
Safety
Crotonaldehyde is a potent irritant even at the ppm levels. It is not very toxic, with an -1">50 of 174 mg/kg (rats, oral).[1]
See also
References
- ↑ 1.0 1.1 1.2 R. P. Schulz; J. Blumenstein; C. Kohlpaintner (2005). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_083.
- ↑ Longley Jr., R. I..; Emerson, W. S.; Blardinelli, A. J. (1954). "3,4-Dihydro-2-methoxy-4-methyl-2H-pyran". Org. Synth. 34: 29. doi:10.15227/orgsyn.034.0029.
- ↑ Coburn, E. R. (1947). "3-Penten-2-ol". Org. Synth. 27: 65. doi:10.15227/orgsyn.027.0065.
- ↑ Dittmar, Heinrich; Drach, Manfred; Vosskamp, Ralf; Trenkel, Martin E.; Gutser, Reinhold; Steffens, Günter (2009). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.n10_n01.
- ↑ Müller, Marc-André; Schäfer, Christian; Litta, Gilberto; Klünter, Anna-Maria; Traber, Maret G.; Wyss, Adrian; Ralla, Theo; Eggersdorfer, Manfred et al. (6 December 2022). "100 Years of Vitamin E: From Discovery to Commercialization". European Journal of Organic Chemistry 2022 (45). doi:10.1002/ejoc.202201190. https://pure.rug.nl/ws/files/373357775/100_Years_of_Vitamin_E.pdf.
- ↑ Childs, Ronald F.; Mulholland, D. Lindsay; Nixon, Alan (1982-03-15). "Lewis acid addticts of α,β-unsaturated carbonyl and nitrile compounds. A calorimetric study" (in en). Canadian Journal of Chemistry 60 (6): 809–812. doi:10.1139/v82-118. ISSN 0008-4042. https://cdnsciencepub.com/doi/10.1139/v82-118.
- ↑ Erdmann, Philipp; Schmitt, Manuel; Janus, Lara; Greb, Lutz (2025-02-17). "Critical Evaluation of Childs Method for the NMR Spectroscopic Scaling of Effective Lewis Acidity: Limitations and Resolution of Earlier Discrepancies" (in en). Chemistry – A European Journal 31 (10). doi:10.1002/chem.202404181. ISSN 0947-6539. https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202404181.
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