# Ethylene oxide: Production route

A silver catalyst and a race against burning

Source page: https://www.materialinsights.org/chemicals/ethylene_oxide/routes/

What this tab covers How it is made: the main production routes or, for product families, the main product types and technologies, compared on share of supply, inputs per tonne, plant scale, yield, co-products and unit cost.

Nearly all EO is made by direct oxidation of ethylene with oxygen over a silver catalyst, using licensed technology from Shell (CRI), Dow (Univation/Meteor), Scientific Design or Sinopec. Older air-based plants and the obsolete chlorohydrin route survive only in a few places. The key differences between plants are catalyst selectivity, which sets ethylene use and CO2 output, and whether EO is sold as purified EO or converted to glycols.

#### Routes compared

| Route | Share of supply | Inputs per tonne | Typical scale | Yield | Co-products | Unit cost |
|---|---|---|---|---|---|---|
| **Oxygen-based direct oxidation (with glycols)** | over 95% of global capacity (indicative) | about 0.75 t ethylene and 0.7 t oxygen per t EO (indicative) | 200-1,000 kt/yr EO; e.g. Sinopec Zhenhai No. 2 EO 200 kt with EG 800 kt (Argus) | selectivity 85-90% (indicative) | CO2 about 0.3-0.4 t per t EO; steam | ethylene is about 75-85% of cash cost (indicative) |
| **Air-based direct oxidation** | small, declining (indicative) | about 0.8-0.9 t ethylene per t EO (indicative) | older units 50-200 kt/yr | selectivity 70-80% (indicative) | more CO2 | higher than oxygen route |
| **Purified EO for derivatives and sterilisation** | about 30% of EO output (indicative) | same as above plus distillation steam | 50-300 kt/yr purified EO | n/a | none | Europe purified EO contract €1,294/t (Oct 2025); US 56.20 c/lb (about $1,239/t, Aug 2025) (Argus) |

#### How each route works
**Oxygen-based direct oxidation (with glycols)**

Ethylene, oxygen and methane ballast circulate over a silver catalyst in multitubular reactors at 220-280°C and 1-3 MPa. EO is absorbed in water, then either purified or hydrolysed to MEG. CO2 is removed in a carbonate loop.

Mature and efficient, but process CO2 is inherent and EO is hazardous.
 Argus Oct 2025; indicative (industry standard) **Air-based direct oxidation**

Older variant using air instead of pure oxygen; lower selectivity and a vent stream of nitrogen.

No ASU needed, but wastes ethylene.
 indicative **Purified EO for derivatives and sterilisation**

Part of reactor EO is distilled to 99.9% and sold to ethoxylation, ethanolamine and sterilisation users, usually within a few hundred kilometres.

Higher value, but logistics and safety limit reach.
 Argus Oct 2025 Unit economics are indicative ranges from the sources named; costs move with feedstock and energy prices, plant size and region.

## Other sections

- [Summary](https://www.materialinsights.org/chemicals/ethylene_oxide/index.md)
- [Overview](https://www.materialinsights.org/chemicals/ethylene_oxide/overview/index.md)
- [Correlation](https://www.materialinsights.org/chemicals/ethylene_oxide/correlation/index.md)
- [Production](https://www.materialinsights.org/chemicals/ethylene_oxide/production/index.md)
- [Feedstocks](https://www.materialinsights.org/chemicals/ethylene_oxide/feedstocks/index.md)
- [Cycles](https://www.materialinsights.org/chemicals/ethylene_oxide/cycles/index.md)
- [Trading](https://www.materialinsights.org/chemicals/ethylene_oxide/trading/index.md)
- [Movement](https://www.materialinsights.org/chemicals/ethylene_oxide/movement/index.md)
- [Regulation](https://www.materialinsights.org/chemicals/ethylene_oxide/regulation/index.md)
- [Characteristics](https://www.materialinsights.org/chemicals/ethylene_oxide/characteristics/index.md)
- [Emissions](https://www.materialinsights.org/chemicals/ethylene_oxide/emissions/index.md)
- [Relationships](https://www.materialinsights.org/chemicals/ethylene_oxide/links/index.md)