Ацетофенон

CAS 98-86-2. Molecular weight 120.15. The simplest aromatic ketone: one benzene ring, one acetyl group. Colourless crystals below 20°C; a pale yellow oily liquid above. Industrially, acetophenone is produced as a byproduct of the cumene-to-phenol process (Hock rearrangement), where a methyl group migrates instead of the expected phenyl group. It also forms during the oxidation of ethylbenzene.

The smell sits in the almond-cherry corridor occupied by benzaldehyde, but acetophenone is softer. Less cyanide-sharp, more powdery. At dilution (below 1%), a hawthorn-floral quality emerges — closer to mimosa absolute than to almond extract. There is also a faint waxy-narcotic undertone, almost orange-blossom, that makes it useful in white-floral bases where a touch of edible sweetness is wanted without going fully gourmand.

Acetophenone occurs naturally in castoreum (beaver castor sacs) and in foods such as apple, apricot, banana, cheese, beef and cauliflower. It is also a natural constituent of several plant extracts used in perfumery, Cistus (labdanum) oils and extracts in particular.

Regulatory note: in March 2025, ECHA's Risk Assessment Committee (RAC) published an opinion recommending that acetophenone be classified Repr. 1B (H360FD). The EU Cosmetics Regulation bans substances classified CMR 1B unless an exemption is granted, and the cosmetics industry chose not to defend acetophenone as an ingredient in its own right. A consortium formed with the help of the European Federation of Essential Oils (EFEO) defended instead its presence as a constituent of natural complex substances. In its final opinion of 14 October 2026, the SCCS judged it safe in that role up to 100 ppm (0.01%) in finished cosmetic products, for adults and children from the age of three. TGSC recommends a maximum of 2.0% in the fragrance concentrate.

Explore all seven extraits in the Discovery Set.

—

Related: Almond · Benzaldehyde · Black Walnut · Brazil Nut · Breadnut · Candlenut · Cashew · Chestnut

Sources

1. PubChem — Acetophenone (CID 7410)
2. Wikipedia — Acetophenone
3. Wikipedia — Castoreum
4. The Good Scents Company — acetophenone
5. IFRA — Acetophenone (ECHA RAC opinion, 2025)
6. European Commission — Request for an SCCS opinion on acetophenone
7. EFEO — Call for interest to defend natural complex substances containing acetophenone (via CTPA)
8. SCCS — Opinion on the safety of acetophenone (SCCS/1689/26, 2026)
9. Dias & Ressler (2014), Nature Neuroscience 17: 89–96