Ethylene Oxide (EtO) — properties & hazards overview
Boiling point
≈ 10.5 °C
Flash point
≈ −20 °C (very low)
Explosion limits (air)
~ 3–100 vol% (very wide)
Water solubility
Miscible; hydrolyses to ethylene glycol
Toxicity
Acute + CNS effects
Flammability
Very low FP; wide LEL–UEL
Chronic risk
Carcinogenic (IARC 1)
Environmental
COD (glycol in blowdown)
| Property | Value / Note |
|---|---|
| Chemical identity | Reactive epoxide; powerful alkylating/sterilant gas; colourless with sweet/ether-like odour (not reliable for warning). |
| Molar mass | 44.05 g/mol; gas at ambient, liquefies under pressure. |
| Reactivity | Ring-opening with water/alcohols (→ ethylene glycol/ethers); polymerises on heat/contamination; incompatible with acids, bases, oxidisers, and many metal salts. |
| Behaviour in gas streams | High water affinity + rapid hydrolysis → effective removal via water (slightly acidified) scrubber; manage heat and viscous glycol build-up (fouling). |
| Best analytical detection | FTIR (inline) — strong, characteristic IR bands enable continuous, reagent-free monitoring from ppm to low % for process control and outlet compliance checks. |
*Indicative values; verify exact limits and design data via current SDS/regulations (“verify via SDS”).