Oxirane

Ethylene oxide

Names
IUPAC name oxirane
Other names epoxyethane, ethylene oxide, dimethylene oxide, oxacyclopropane, 1,2-Epoxy ethane
Identifiers
CAS Number	75-21-8 Y
3D model (Jmol)	Interactive image
Abbreviations	EO, EtO
ChEBI	CHEBI:27561 Y
ChemSpider	6114 Y
ECHA InfoCard	100.000.773
EC Number	200-849-9
KEGG	D03474 Y
MeSH	Ethylene+Oxide
PubChem	6354
RTECS number	KX2450000
UNII	JJH7GNN18P Y
InChI InChI=1S/C2H4O/c1-2-3-1/h1-2H2 Y Key: IAYPIBMASNFSPL-UHFFFAOYSA-N Y InChI=1/C2H4O/c1-2-3-1/h1-2H2 Key: IAYPIBMASNFSPL-UHFFFAOYAX
SMILES C1CO1
Properties
Chemical formula	C2H4O
Molar mass	44.05 g mol−1
Appearance	colorless gas
Odor	ether-like
Density	0.882 g/mL, 7.360 lbs/gallon
Melting point	−111.3 °C (−168.3 °F; 161.8 K)
Boiling point	10.7 °C (51.3 °F; 283.8 K)
Solubility in water	miscible
Vapor pressure	1.46 atm (20°C)
Magnetic susceptibility (χ)	-30.7·10−6 cm3/mol
Thermochemistry
Std molar entropy (So298)	243 J mol−1 K−1
Std enthalpy of formation (ΔfHo298)	−52.6 kJ mol−1
Hazards
Main hazards	carcinogen extremely flammable
Safety data sheet	ICSC 0155
EU classification (DSD)	F+ T Carc. Cat. 1
R-phrases	R45, R46, R12, R23, R36/37/38
S-phrases	S53, S45
NFPA 704	4 3 3
Flash point	−20 °C (−4 °F; 253 K)
Autoignition temperature	429 °C (804 °F; 702 K)
Explosive limits	3 to 100%
Lethal dose or concentration (LD, LC):
LC50 (median concentration)	836 ppm (mouse, 4 hr) 4000 ppm (rat, 4 hr) 800 ppm (rat, 4 hr) 819 ppm (guinea pig, 4 hr) 1460 ppm (rat, 4 hr) 835 ppm (mouse, 4 hr) 960 ppm (dog, 4 hr)
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 1 ppm 5 ppm [15-minute Excursion]
REL (Recommended)	Ca TWA <0.1 ppm (0.18 mg/m3) C 5 ppm (9 mg/m3) [10-min/day]
IDLH (Immediate danger)	Ca [800 ppm]
Related compounds
Related heterocycles	Aziridine, Thiirane, Borirane
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

Ethylene oxide, properly called oxirane by IUPAC, is the organic compound with the formula C
2H
4O. It is a cyclic ether. (A cyclic ether consists of an alkane with an oxygen atom bonded to two carbon atoms of the alkane, forming a ring.) Ethylene oxide is a colorless flammable gas at room temperature, with a faintly sweet odor; it is the simplest epoxide: a three-membered ring consisting of one oxygen atom and two carbon atoms. Because of its special molecular structure, ethylene oxide easily participates in addition reactions; e.g., opening its ring and thus easily polymerizing. Ethylene oxide is isomeric with acetaldehyde and with vinyl alcohol.

Although it is a vital raw material with diverse applications, including the manufacture of products like polysorbate 20 and polyethylene glycol (PEG) that are often more effective and less toxic than alternative materials, ethylene oxide itself is a very hazardous substance. At room temperature it is a flammable, carcinogenic, mutagenic, irritating, and anaesthetic gas, with a misleadingly pleasant aroma.

The chemical reactivity that is responsible for many of ethylene oxide's hazards has also made it a key industrial chemical. Although too dangerous for direct household use and generally unfamiliar to consumers, ethylene oxide is used industrially for making many consumer products as well as non-consumer chemicals and intermediates. Ethylene oxide is important or critical to the production of detergents, thickeners, solvents, plastics, and various organic chemicals such as ethylene glycol, ethanolamines, simple and complex glycols, polyglycol ethers and other compounds. As a poison gas that leaves no residue on items it contacts, pure ethylene oxide is a disinfectant that is widely used in hospitals and the medical equipment industry to replace steam in the sterilization of heat-sensitive tools and equipment, such as disposable plastic syringes.