Ethylene: Characteristics
Why trace impurities can wreck a polymer plant
What this tab covers The physical and chemical properties that set its grade, price and uses, with the commercial grades and the standards that define them.Ethylene is sold almost entirely as polymer grade, because trace impurities poison polymerisation catalysts. Purity, acetylene and oxygenate limits, and the fact that it boils at -104°C drive how it is handled, stored and priced.
Properties that matter commercially
| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| Purity | polymer grade at least 99.9 mol% ethylene | Ziegler-Natta and metallocene catalysts are poisoned by acetylene, CO, sulphur and water at ppm levels. | industry standard (indicative) |
| Boiling point | -103.7°C at 1 atm | Requires refrigerated storage and ships, which limits trade. | standard physical data |
| Acetylene content | typically under 1-2 ppm | Removed by selective hydrogenation; key spec for PE and EO. | industry standard (indicative) |
| Flammability range | about 2.7-36% in air | Wide range means strict leak and ignition control. | standard safety data |
Commercial grades
- Polymer grade (99.9%+): PE, EO, most derivatives
- Chemical grade (about 99%+): some EDC and ethylbenzene units
- Bio-ethylene: certified renewable carbon, for bio-PE