Substance profile
Ethylene oxide
Ethylene oxide is a colorless gas at ordinary room temp and pressure; liquid below 12 °C with a sweet odor.
01 · Identification
What Ethylene oxide is
Ethylene oxide is a colorless gas at ordinary room temp and pressure; liquid below 12 °C with a sweet odor. Its molecular formula is C2H4O and its molecular weight is 44.05 g/mol. It boils at 10.6 °C, melts at -112 °C, is soluble in water.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
Other names for Ethylene oxide
- EtO
- EO
- oxirane
- 12/88
- Alpha, Beta-Oxidoethane
- Amprolene
- Anprolene
- Anproline
- Ciba-Geigy 9138
- Dihydrooxirene
- Dimethylene Oxide
- E O
- E.O.
- Ent-26263
- 1,2-Epoxy Ethane
02 · GHS classification
Hazards and label elements
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
| Code | Hazard statement |
|---|---|
| H220 | Extremely flammable gas. |
| H350 | May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H340 | May cause genetic defects <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H360Fd | May damage fertility. Suspected of damaging the unborn child. |
| H331 | Toxic if inhaled. |
| H301 | Toxic if swallowed. |
| H335 | May cause respiratory irritation. |
| H336 | May cause drowsiness or dizziness. |
| H372 | Causes damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H314 | Causes severe skin burns and eye damage. |
| H318 | Causes serious eye damage. |
Precautionary statements: P201, P210, P233, P260, P270, P271, P280, P301, P304, P305, P308, P310, P313, P314, P330, P331, P338, P403
03 · Physical and chemical properties
Ethylene oxide properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 10.6 °C (51.1 °F) | HSDB | |
| 10.56 °C (51 °F) | NIOSH | ||
| 10.72 °C (51.3 °F) | at 760 mmHg | CAMEO | |
| Melting point | -111.7 °C (-169.1 °F) | HSDB | |
| -112.78 °C (-171 °F) | NIOSH | ||
| -112.5 °C (-170.5 °F) | CAMEO | ||
| Density | 0.9 g/cm³ | ICSC | |
| 0.882 g/cm³ | at 10 °C | HSDB | |
| 0.82 g/cm³ | at 10 °C | NIOSH | |
| Solubility | Soluble in benzene, acetone, ethanol, ether | HSDB | |
| Miscible with... carbon tetrachloride. | HSDB | ||
| Miscible with water | HSDB | ||
| Vapor pressure | 1110 mmHg | NIOSH | |
| 1095 mmHg | at 20 °C | CAMEO | |
| 1310 mmHg | at 25 °C | HSDB | |
| Flash point | -28.89 °C (-20 °F) | HSDB | |
| -18 °C (-0.4 °F) | open cup | HSDB | |
| Autoignition temperature | 428.89 °C (804 °F) | HSDB | |
| 429 °C (804.2 °F) | ICSC | ||
| Lower explosive limit (LEL) | 3 % by volume | HSDB | |
| Upper explosive limit (UEL) | 100 % by volume | HSDB | |
| Vapor density | 1.49 (air = 1) | HSDB | |
| 1.5 (air = 1) | ICSC | ||
| Odor threshold | Recognition: 1.5 mg/cu m= 0.8 ppm, mean detection concn: 700 ppm; absolute perception limit: 260 ppm; 50% recognition: 500 ppm; 100% recognition: 500 ppm | HSDB | |
| Low: 520 mg/cu m; High: 1400 mg/cu m | HSDB | ||
| 300 ppm in air | HSDB | ||
| Critical temperature and pressure | 196 °C (384.8 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Ethylene oxide
Storage conditions
Store EtO in tightly closed cylinders or tanks in a cool, shaded, well-ventilated, explosion-proof area.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Forms explosive mixture with air. Dangerously reactive; may rearrange chemically and/or polymerize violently with evolution of heat, when in contact with highly active catalytic surfaces such as anhydrous chlorides or iron, tin and aluminum, pure oxides of iron and aluminum, and alkali metal hydroxides. Even small amounts of strong acids, alkalis, oxidizers can cause a reaction. Avoid contact with copper. Protect container from physical damage, sun and heat. Attacks some plastics, rubber or coatings.
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Ethylene oxide in the storage compatibility matrix →
Next