Purified terephthalic acid
The white powder that, with MEG, makes all polyester fibre and PET bottles; China dominates and India is a large importer.
Commodity chemicals · Derivatives & intermediates · No. 40
- Single chemical
- Feedstock: Oil, gas or coal
- about 85 Mt a year of demand (2025, indicative, basis: world PX demand of about 57 Mt at 0.66 t PX per t PTA; China capacity 87-88 Mt run at about 70-75%)
- 1.3 t CO₂e per t
- HS 291736
A plain white powder, made almost entirely in China, is the backbone of every polyester garment and PET bottle.
Chart: Illustration: Purified terephthalic acid
Where it comes from
Chart: Map of where it comes from
Paraxylene is oxidised with air in acetic acid over a cobalt-manganese-bromide catalyst, then the crude acid is hydrogenated to strip out impurities that would colour the polymer.
Three things to know
- Each tonne of polyester needs about 0.86 t of PTA, and 68% of PTA goes into polyester fibre.
- Chinese processing fees were around CNY 200 a tonne in July to October 2025, which meant losses for many plants.
- India's imports rose 9.1% to 1.95 Mt in January to November 2025 after a quality-control order blocking Chinese supply was revoked.
The journey
- 1 ParaxyleneAbout 0.66 t PX per tonne
- 2 OxidationAir, acetic acid, cobalt catalyst, 200 C
- 3 PurificationHydrogenated over palladium to remove 4-CBA
- 4 PolymerisationJoined with MEG into PET melt
- 5 End productsYarn, staple fibre, bottle resin, film