Crotonaldehyde

Crotonaldehyde[1]
Names
	IUPAC name (2E)-but-2-enal
	Other names Crotonaldehyde; Crotoinic aldehyde; β-Methacrolein; β-Methyl acrolein; 2-butenal; Propylene aldehyde
Identifiers
CAS Number	4170-30-3 (E/Z) ; 123-73-9 (E) ; 15798-64-8 (Z) ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:41607 ;
ChEMBL	ChEMBL1086445 ;
ChemSpider	394562 ;
DrugBank	DB04381 ;
ECHA InfoCard	100.021.846
EC Number	204-647-1;
IUPHAR/BPS	6288;
KEGG	C19377 ;
PubChem CID	447466;
RTECS number	GP9499000;
UNII	9G72074TUW (E/Z) ; 6PUW625907 (E) ; RB9WCA91QT (Z) ;
UN number	1143
CompTox Dashboard (EPA)	DTXSID8024864 ;
	InChI InChI=1S/C4H6O/c1-2-3-4-5/h2-4H,1H3/b3-2+ Key: MLUCVPSAIODCQM-NSCUHMNNSA-N ; InChI=1/C4H6O/c1-2-3-4-5/h2-4H,1H3/b3-2+ Key: MLUCVPSAIODCQM-NSCUHMNNBQ;
	SMILES O=C/C=C/C;
Properties
Chemical formula	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)
Solubility in water	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
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H225, H301, H310, H311, H315, H318, H330, H335, H341, H373, H400
GHS precautionary statements	P201, P202, P210, P233, P240, P241, P242, P243, P260, P261, P262, P264, P270, P271, P273, P280, P281, P284, P301+310, P302+350, P302+352, P303+361+353, P304+340, P305+351+338, P308+313
NFPA 704 (fire diamond)	3 4 2
Flash point	13 °C (55 °F; 286 K)
Autoignition; temperature	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]
	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).
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	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 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.[5] It is a Michael acceptor. Addition of methylmagnesium chloride produces 3-penten-2-ol.[6]

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.[7]

Uses

Crotonylidene diurea is a specialty fertilizer.[8]

It is 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. It adds two equivalents of urea to give the pyrimidine derivative that is employed as a controlled-release fertilizer. [4]

Safety

Crotonaldehyde is a potent irritant even at the ppm levels. It is not very toxic, with an LD50 of 174 mg/kg (rats, oral).[4]

References

Merck Index, 11th Edition, 2599
NIOSH Pocket Guide to Chemical Hazards. "#0157". National Institute for Occupational Safety and Health (NIOSH).
"Crotonaldehyde". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
R. P. Schulz, J. Blumenstein, C. Kohlpaintner (2005). "Crotonaldehyde and Crotonic Acid". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_083.CS1 maint: uses authors parameter (link)
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.
https://jadedman.wordpress.com/2011/01/08/catalysts/
Dittmar, Heinrich; Drach, Manfred; Vosskamp, Ralf; Trenkel, Martin E.; Gutser, Reinhold; Steffens, Günter (2009). "Fertilizers, 2. Types". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.n10_n01.

External links

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[1] Merck Index, 11th Edition, 2599

[PGCH-2] NIOSH Pocket Guide to Chemical Hazards. "#0157". National Institute for Occupational Safety and Health (NIOSH).

[IDLH-3] "Crotonaldehyde". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[Schulz-4] R. P. Schulz, J. Blumenstein, C. Kohlpaintner (2005). "Crotonaldehyde and Crotonic Acid". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_083.CS1 maint: uses authors parameter (link)

[5] 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.

[6] Coburn, E. R. (1947). "3-Penten-2-ol". Org. Synth. 27: 65. doi:10.15227/orgsyn.027.0065.

[7] ttps://jadedman.wordpress.com/2011/01/08/catalysts/

[Ull-8] Dittmar, Heinrich; Drach, Manfred; Vosskamp, Ralf; Trenkel, Martin E.; Gutser, Reinhold; Steffens, Günter (2009). "Fertilizers, 2. Types". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.n10_n01.