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Crotonaldehyde

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Crotonaldehyde[1]
Skeletal formula of crotonaldehyde
Ball-and-stick model of (Z)-crotonaldehyde
Names
IUPAC name
(2E)-but-2-enal
Other names
Crotonaldehyde
Crotoinic aldehyde
β-Methacrolein
β-Methyl acrolein
2-butenal
Propylene aldehyde
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.021.846 Edit this at Wikidata
EC Number
  • 204-647-1
KEGG
UNII
  • InChI=1S/C4H6O/c1-2-3-4-5/h2-4H,1H3/b3-2+ checkY
    Key: MLUCVPSAIODCQM-NSCUHMNNSA-N checkY
  • InChI=1/C4H6O/c1-2-3-4-5/h2-4H,1H3/b3-2+
    Key: MLUCVPSAIODCQM-NSCUHMNNBQ
  • O=C/C=C/C
Properties
C4H6O
Molar mass 70.091 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)
18% (20°C)[2]
Solubility very soluble in ethanol, ethyl ether, acetone
soluble in chloroform
miscible in benzene
Vapor pressure 19 mmHg (20°C)[2]
1.4362
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no code
4
3
2
Flash point 13 °C (55 °F; 286 K)
207 °C (405 °F; 480 K)
Explosive limits 2.1-15.5%
Lethal dose or concentration (LD, LC):
600 ppm (rat, 30 min)
1375 ppm (rat, 30 min)
519 ppm (mouse, 2 hr)
1500 ppm (rat, 30 min)[3]
400 ppm (rat, 1 hr)[3]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 2 ppm (6 mg/m3)[2]
REL (Recommended)
 TWA 2 ppm (6 mg/m3)[2]
IDLH (Immediate danger)
 50 ppm[2]
Related compounds
Related alkenals
 Acrolein

cis-3-hexenal
(E,E)-2,4-Decadienal

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

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.[4]

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.[4]

Crotonaldehyde is a multifunctional molecule that exhibits diverse reactivity. It is an excellent prochiral dienophile.[5] It is a Michael acceptor. Addition of methylmagnesium chloride produces 3-penten-2-ol.[6]

The reaction of crotonaldehyde with ethanol then gives kethoxal (anhydrous).

Polyurethane catalyst N,N,N',N'-tetramethyl-1,4-butanediamine (also known as TMBDA) is obtained by hydrogenating N,N,N',N'-tetramethyl-1,4-butenediamine which is a reaction product of crotonaldehyde and dimethylamine.[7]

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. It is used to make preservatives.

See also

References

  1. ^ Merck Index, 11th Edition, 2599
  2. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0157". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ a b "Crotonaldehyde". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. ^ a b "Crotonaldehyde and Crotonic Acid". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. 2005. doi:10.1002/14356007.a08_083. ISBN 978-3527306732. {{cite encyclopedia}}: Unknown parameter |authors= ignored (help)
  5. ^ Longley, Jr., R. I..; Emerson, W. S.; Blardinelli, A. J. (1963). "3,4-Dihydro-2-methoxy-4-methyl-2H-pyran". Organic Syntheses{{cite journal}}: CS1 maint: multiple names: authors list (link); Collected Volumes, vol. 4, p. 311.
  6. ^ Coburn, E. R. (1955). "3-Penten-2-ol". Organic Syntheses; Collected Volumes, vol. 3, p. 696.
  7. ^ https://jadedman.wordpress.com/2011/01/08/catalysts/
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