Acrolein

Acrolein

Names
IUPAC name Prop-2-enal
Other names Acraldehyde Acrylic aldehyde Allyl Aldehyde Ethylene Aldehyde Acrylaldehyde
Identifiers
CAS Number	107-02-8 Y
3D model (Jmol)	Interactive image Interactive image
ChEBI	CHEBI:15368 Y
ChEMBL	ChEMBL721 Y
ChemSpider	7559 Y
ECHA InfoCard	100.003.141
IUPHAR/BPS	2418
KEGG	C01471 Y
PubChem	7847
UNII	7864XYD3JJ Y
InChI InChI=1S/C3H4O/c1-2-3-4/h2-3H,1H2 Y Key: HGINCPLSRVDWNT-UHFFFAOYSA-N Y InChI=1/C3H4O/c1-2-3-4/h2-3H,1H2 Key: HGINCPLSRVDWNT-UHFFFAOYAQ
SMILES O=CC=C C=CC=O
Properties
Chemical formula	C3H4O
Molar mass	56.06 g·mol−1
Appearance	Colorless to yellow liquid. Colorless gas in smoke.
Odor	irritating
Density	0.839 g/mL
Melting point	−88 °C (−126 °F; 185 K)
Boiling point	53 °C (127 °F; 326 K)
Solubility in water	Appreciable (> 10%)
Vapor pressure	210 mmHg
Hazards
Main hazards	Highly poisonous. Causes severe irritation to exposed membranes. Extremely flammable liquid and vapor.
Safety data sheet	JT Baker MSDS
NFPA 704	3 3 2
Flash point	−26 °C (−15 °F; 247 K)
Autoignition temperature	278 °C (532 °F; 551 K)
Explosive limits	2.8-31%
Lethal dose or concentration (LD, LC):
LC50 (median concentration)	875 ppm (mouse, 1 min) 175 ppm (mouse, 10 min) 150 ppm (dog, 30 min) 8 ppm (rat, 4 hr) 375 ppm (rat, 10 min) 25.4 ppm (hamster, 4 hr) 131 ppm (rat, 30 min)
LCLo (lowest published)	674 ppm (cat, 2 hr)
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 0.1 ppm (0.25 mg/m3)
REL (Recommended)	TWA 0.1 ppm (0.25 mg/m3) ST 0.3 ppm (0.8 mg/m3)
IDLH (Immediate danger)	2 ppm
Related compounds
Related alkenals	Crotonaldehyde 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).
Y  (what is YN ?)
Infobox references

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

Acrolein (systematic name: propenal) is the simplest unsaturated aldehyde. It is a colourless liquid with a piercing, disagreeable, acrid smell. The smell of burnt fat (as when cooking oil is heated to its smoke point) is caused by glycerol in the burning fat breaking down into acrolein. It is produced industrially from propylene and mainly used as a biocide and a building block to other chemical compounds, such as the amino acid methionine.

Acrolein is prepared industrially by oxidation of propene. The process uses air as the source of oxygen and requires metal oxides as heterogeneous catalysts:

About 500,000 tons of acrolein are produced in this way annually in North America, Europe, and Japan. Additionally, all acrylic acid is produced via the transient formation of acrolein. The main challenge is in fact the competing overoxidation to this acid. Propane represents a promising but challenging feedstock for the synthesis of acrolein (and acrylic acid).

When glycerol (also called glycerin) is heated to 280 °C, it decomposes into acrolein:

This route is attractive when glycerol is co-generated in the production of biodiesel from vegetable oils or animal fats. The dehydration of glycerol has been demonstrated but has not proven competitive with the route from petrochemicals.

The original industrial route to acrolein, developed by Degussa, involves condensation of formaldehyde and acetaldehyde: