Ethylene oxide
| Names | |
|---|---|
| IUPAC name
Oxirane
| |
| Other names
1,2-Epoxy ethane
Amprolene Dimethylene oxide Epoxyethane Oxacyclopropane | |
| Properties | |
| C2H4O | |
| Molar mass | 44.05 g/mol |
| Appearance | Colorless gas |
| Odor | Sweet, ether-like |
| Density | 0.882 g/cm3 (at 10 °C) |
| Melting point | −111.3 °C (−168.3 °F; 161.8 K) |
| Boiling point | 10.7 °C (51.3 °F; 283.8 K) |
| Miscible | |
| Solubility | Miscible with carbon tetrachloride, ethers Soluble in acetone, benzene, diethyl ether, ethanol |
| Vapor pressure | 1.46 atm (20°C) |
| Thermochemistry | |
| Std molar
entropy (S |
243 J·mol−1·K−1 |
| Std enthalpy of
formation (ΔfH |
−52.6 kJ·mol−1 |
| Hazards | |
| Safety data sheet | Praxair |
| Flash point | −20 °C |
| 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) |
| Related compounds | |
| Related compounds
|
Propylene oxide |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Ethylene oxide, properly called oxirane by IUPAC, is the organic compound with the formula C2H4O. It is the simplest epoxide and cyclic ether. Ethylene oxide is isomeric with acetaldehyde and vinyl alcohol.
Contents
Properties
Chemical
Ethylene oxide is highly flammable and will burn in open air.
- C2H4O + 5/2 O2 → 2 CO2 + 2 H2O
Physical
Ethylene oxide is a colorless gas at room temperature, but liquid below 10°C, with a sweet ether-like smell (some sources say bruised-apple like[1]). It is miscible with water, carbon tetrachloride and other organic solvents.
Availability
Ethylene oxide is sold by various chemical suppliers, either pure or in solution, but due to its strong carcinogenicity its sale is restricted to companies.
Preparation
The preparation of ethylene oxide is not easy, but can be done if the procedure is followed carefully.
Industrially EO is made through direct oxidation of ethylene with oxygen in the presence of a metal catalyst, such as silver.
A more convenient process involves the reaction of 2-chloroethanol with a base, such as calcium hydroxide.
- 2 OH–CH2CH2–Cl + Ca(OH)2 → 2 (CH2CH2)O + CaCl2 + 2 H2O
The resulting ethylene oxide is purified through rectification and condensed.
Another route is to absorb dry hydrogen chloride gas into warm ethylene glycol, in the presence of anhydrous zinc chloride and distill the resulting 2-chloroethanol. Some water will also distill and must be removed. Plenty of 1,2-dichloroethane will be produced as a side product.
1,2-Diiodoethane will react with silver oxide to yield ethylene oxide at high temperatures.
- Ag2O + I-CH2-CH2-I → 2 AgI + (CH2CH2)O
A less known route involves refluxing dichloroethane at 105 °C in the presence of potassium hydroxide and sodium formate.[2]
Projects
Ethylene glycol is a very useful reagent, but its use is limited due to its toxicity and flammability. Wear proper protection when working with the compound.
- Make polyethylene glycol
- Make very pure ethylene glycol
- Preparation of ethanolamines
- Phenethyl alcohol synthesis
- Make ethylene carbonate
Handling
Safety
Ethylene oxide is extremely flammable, very toxic and a potent carcinogen. It's sweet smell can induce the false sense of safety.
Storage
Ethylene oxide should be stored in gas cylinders or metallic containers, in dark well ventilated areas. Avoid storing it in glass containers and in the freezer, since unless you live at the North Pole, any rise in temperature over its low boiling point may end up in a disaster.
Disposal
Ethylene oxide can be safely burned outside. Hydrolysis will lead to ethylene glycol which is non-volatile and safer to handle.
References
- ↑ Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 562
- ↑ Zahalka, Hayder A.; Sasson, Yoel; Synthesis; nb. 9; (1986); p. 763 - 765
