Crotonaldehyde
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-Crotonaldehyde_3D_ball.png) | |
| Names | |
|---|---|
| IUPAC name
(2E)-but-2-enal | |
| Other names
Crotonaldehyde Crotoinic aldehyde β-Methacrolein β-Methyl acrolein 2-butenal Propylene aldehyde | |
| Identifiers | |
4170-30-3 (E/Z)  123-73-9 (E) 15798-64-8 (Z) | |
| 3D model (Jmol) | Interactive image |
| ChEBI | CHEBI:41607  |
| ChEMBL | ChEMBL1086445 |
| ChemSpider | 394562 |
| DrugBank | DB04381 |
| ECHA InfoCard | 100.021.846 |
| EC Number | 204-647-1 |
| 6288 | |
| KEGG | C19377 |
| PubChem | 447466 |
| UNII | 9G72074TUW ("E/Z") 6PUW625907 ("E") RB9WCA91QT ("Z") |
| |
| |
| Properties | |
| C4H6O | |
| Molar mass | 70.09 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] |
| Refractive index (nD) |
1.4362 |
| Hazards | |
| R-phrases | R11 R24/25 R26 R37/38 R41 R48/22 R50 R68 |
| S-phrases | S26 S28 S36/37/39 S45 S61 |
| NFPA 704 | |
| 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): | |
| LC50 (median concentration) |
600 ppm (rat, 30 min) 1375 ppm (rat, 30 min) 519 ppm (mouse, 2 hr) 1500 ppm (rat, 30 min)[3] |
| LCLo (lowest published) |
400 ppm (rat, 1 hr)[3] |
| US health exposure limits (NIOSH): | |
| 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 |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| verify (what is ?) | |
| Infobox 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.[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 affords 3-penten-2-ol.[6]
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
- ↑ Merck Index, 11th Edition, 2599
- 1 2 3 4 5 "NIOSH Pocket Guide to Chemical Hazards #0157". National Institute for Occupational Safety and Health (NIOSH).
- 1 2 "Crotonaldehyde". Immediately Dangerous to Life and Health. National Institute for Occupational Safety and Health (NIOSH).
- 1 2 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
- ↑ 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, p. 311
- ↑ Coburn, E. R. (1955). "3-Penten-2-ol". Org. Synth.; Coll. Vol., 3, p. 696