Acrylonitrile: Production route
The 1960 process that still makes nearly all of it
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.Almost all ACN is made by propylene ammoxidation, the SOHIO process introduced in 1960. Licensors and catalyst makers (INEOS, Asahi Kasei, Sinopec, Mitsubishi Chemical) compete on yield. A propane-based ammoxidation route was commercialised by Asahi Kasei in Thailand, but that PTTAC plant (200 kt/yr) stopped in October 2024. Bio-based routes from glycerol or sugars and mass-balance bio-attributed propylene are at pilot or certificate stage.
Routes compared
| Route | Share of supply | Inputs per tonne | Typical scale | Yield | Co-products | Unit cost |
|---|---|---|---|---|---|---|
| Propylene ammoxidation (SOHIO) | over 95% of capacity (indicative) | about 1.1 t propylene, 0.48 t ammonia, air; sulphuric acid for quench (indicative) | 200-700 kt/yr; Zhejiang Petrochemical Daishan Plant 2 is 0.66 Mt (2025) | about 80-83% on propylene (indicative) | HCN about 0.1 t, acetonitrile about 0.025 t, ammonium sulphate, steam (indicative) | about $950-1,050/t at propylene $750/t and ammonia $400/t (indicative: 1.1 x 750 + 0.48 x 400 + conversion, less by-product credits) |
| Propane ammoxidation | near zero after PTTAC closure (Oct 2024) | not published | PTTAC Thailand 200 kt/yr (closed) | lower than propylene route (indicative) | similar | attractive only with cheap propane |
| Bio-based and bio-attributed ACN | very small | not published | certificate volumes in existing plants (indicative) | not published | not published | premium not published |
How each route works
Propylene ammoxidation (SOHIO)Propylene, ammonia and air react in a fluidised bed over bismuth-molybdate catalyst. Off-gas is scrubbed, unreacted ammonia is captured as ammonium sulphate or recycled, and ACN, HCN and acetonitrile are distilled. Steam from the reaction powers the plant and is exported.
mature and cheap; HCN handling; margin swings with propylene
GlobalData via Offshore Technology (plant sizes); indicative Propane ammoxidationPropane replaces propylene, avoiding a dehydrogenation step, over a mixed-metal oxide catalyst.
cheaper feedstock; lower yield and catalyst complexity
ResourceWise 2025 Bio-based and bio-attributed ACNMass-balance: bio-propylene or bio-ammonia is fed into existing plants and certified (ISCC PLUS). Direct routes from glycerol (via acrolein) or sugar-derived intermediates are at pilot scale.
uses existing assets; mass-balance claims draw scepticism
indicative Unit economics are indicative ranges from the sources named; costs move with feedstock and energy prices, plant size and region.