Caprolactam
The monomer for nylon 6 fibre and plastics, made from benzene, ammonia and sulphur, with large ammonium sulphate co-product and N2O emissions.
Commodity chemicals · Derivatives & intermediates · No. 42
- Single chemical
- Feedstock: Oil, gas or coal
- about 7 Mt a year of demand (2024, indicative, basis: about 70% use of 9.9 Mt/yr capacity)
- 4.0 t CO₂e per t
- HS 293371
Making the nylon in your sportswear can also make about 4.4 tonnes of fertiliser for every tonne of monomer.
Chart: Illustration: Caprolactam
Where it comes from
Chart: Map of where it comes from
Benzene becomes cyclohexanone, which reacts with hydroxylamine or with ammonia and hydrogen peroxide to form an oxime. Oleum then rearranges it into the caprolactam ring.
Three things to know
- World capacity was 9.9 Mt a year in 2024 and China held 63%; one Chinese firm, Highsun, has 1.2 Mt alone.
- Older routes make up to about 4.4 t of ammonium sulphate fertiliser per tonne, tying caprolactam to farm markets.
- Chinese producers agreed on 5 November 2025 to cut output by 20% across the board as prices hit multi-year lows.
The journey
- 1 BenzeneAbout 0.9 t per tonne caprolactam
- 2 CyclohexanoneVia cyclohexane oxidation or phenol
- 3 OximeMade with hydroxylamine or by ammoximation
- 4 Beckmann rearrangementOleum step; ammonium sulphate by-product
- 5 Nylon 6Polymerised to chips, spun or compounded