How phenol is made
Phenol was once pulled from coal tar. Now a chain reaction in air makes it, with acetone as a free passenger.
- stations
- 5
- things upstream
- 10
- raw sources
- 5
- steps from the ground
- 5
The short version
Most phenol comes from the cumene process. Benzene and propylene are joined into cumene, the cumene is oxidized with air, and an acid then splits the product into phenol and acetone. Plants turn out about 10.8 million tonnes of phenol this way each year, and most of it becomes plastics and resins.
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Join benzene and propylene
The two cheap feedstocks are compressed together with an acid catalyst. They combine into cumene, which is isopropyl benzene.
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Oxidize the cumene with air
Air is bubbled through the cumene with a small amount of a radical starter. A chain reaction builds up cumene hydroperoxide, an unstable intermediate that plants keep under pressure and carefully controlled.
Goes in -
Split it with acid
An acid breaks the hydroperoxide into two products in a single step. The result is phenol plus acetone, two chemicals with a ready market.
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Distill the two apart
Columns separate acetone, phenol and left-over cumene. Unused cumene returns to the start of the line.
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Ship the liquid
Phenol is stored as a liquid and moved to plants that make resins and plastics.
Worth repeating
- Nearly 10.8 million tonnes of phenol were made by the cumene process in 2022.
- The process was invented in the Soviet Union in 1942 and independently by Heinrich Hock in 1944.
- Joseph Lister used phenol, then called carbolic acid, in his pioneering antiseptic surgery.
Back to the ground
Follow every input upstream and phenol starts as these 5 raw sources.
Where it goes next
Phenol feeds 7 lines directly and reaches 244 things in total.
Further down the line
Keep walking
Sources
Cite this page: "How phenol is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/phenol