Material guide: civetone — the molecule isolated from a secretion that reads "urine, fecal", and its own odour field opens with "clean"

About 5 minutes.

Short version

• Name: civetone, filed as (Z)-civet decenone, also civettone (Firmenich), CAS 542-46-1
• Formula C17H30O, MW 250.43 — a 17-membered macrocyclic ketone
• FEMA 3425, JECFA 1401, CoE 11744, structure class II
• Odour type: musk; odour: clean, musk, dry, animal, sweet
• Strength: high (evaluate at 1.00% or less), rank 3; substantivity 400 hours
• Melting point 37.5–38.5 °C — a solid at room temperature
• Suppliers: 10; the occurrence field reads "civet"
• All three toxicity fields read "Not determined"

Side by side with its source

Civetone is isolated from civet secretion. Put the two records together:

	Civet absolute	Civetone
CAS	68916-26-7	542-46-1
Odour type	animal	musk
Odour field	animal, urine, honey, fecal, balsamic, powdery, fatty, resinous	clean, musk, dry, animal, sweet
Strength	high (evaluate at 10%)	high (evaluate at 1%)
Evaluation solvent	isopropyl myristate	dipropylene glycol
Substantivity	400 h	400 h
Suppliers	17	10

One source, two completely different faces.

The absolute's odour field carries "urine" and "fecal". The principal molecule isolated from it opens with "clean".

Which means civet's animalic quality is not coming from civetone. Those words come from other things in the secretion — molecules like indole and para-cresol are common in animal secretions, and at concentration they read as faecal.

(Concentration flipping a material's character is the subject of the indole article. The difference here is not concentration; it is composition.)

The evaluation concentrations differ tenfold — 10% for the absolute, 1% for the molecule — and so do the solvents: IPM for the absolute (its solubility field lists isopropyl myristate and water, with no alcohol) and DPG for the molecule. The two odour descriptions cannot be compared directly, because the baselines differ.

The (E) isomer has zero suppliers

The database holds ten civet-related records, three of them versions of the same skeleton:

Record	CAS	Suppliers
(Z)-civet decenone (civetone)	542-46-1	10
(E)-civet decenone	1502-37-0	0
Dihydrocivetone	3661-77-6	1

Ten for the (Z), none at all for the (E).

The whole difference is whether that one double bond on a 17-membered ring is cis or trans. This is the same phenomenon as the santalol paper cited in Javanol — isomer configuration can decide whether a molecule has the odour at all.

And for civetone, somebody took that all the way.

Nine fluorinated analogues

What Callejo and colleagues did in Chemistry in 2017 is direct: they put difluoromethylene (CF2) groups into musk-relevant macrocyclic ketones, making nine civetone analogues and five muscone analogues.

The CF2 group has a known tendency — in an aliphatic macrocycle it prefers corner positions over edge positions. So moving it around the ring is a chemical way of bending the ring's conformation.

They then confirmed each analogue's ring shape by X-ray, and had them evaluated in a professional perfumery environment.

The finding:

Structures distorted from the consensus conformation by the particular placement of the CF2 groups lose their musk fragrance and become less pleasant.

They also tested Bersuker's historical conformational model for musk odour and report that it "generally holds".

What this means: musk odour is not decided by having a large ring. It is decided by the shape that ring actually takes.

(Whether a molecule has an odour being a matter of shape rather than its ingredient list is the mirror image of Helvetolide, where the name says -olide and the molecule is not a lactone. There the name misleads; here the formula would.)

The receptor end

Shirasu and colleagues traced musk odours through the mouse olfactory bulb in Neuron in 2014, finding that the small cluster of glomeruli muscone activates is highly specific to macrocyclic ketones, while synthetic musks with nitro, polycyclic or ester moieties activate distinct but nearby glomeruli. They identified the mouse receptor MOR215-1 and the human receptor OR5AN1.

Ahmed and colleagues went on to OR5AN1's molecular mechanism in PNAS in 2018: it responds to musk ketone at nanomolar concentrations and robustly to macrocyclic sulfoxides and fluorine-substituted macrocyclic ketones, while a second receptor, OR1A1, responds only to nitromusks. They also confirmed OR5AN1's preference for (R)- over (S)-muscone.

Civetone is a macrocyclic ketone, so it takes the first route.

The practical implication for a formula is limited — these are receptor and bulb experiments, not formulation guidance. But they explain why the families of synthetic musk are not drop-in substitutes for each other: they do not travel the same line in the nose.

It is a solid, and it works at trace levels

Melting point 37.5–38.5 °C, so at room temperature it is a colourless-to-white crystalline solid. The appearance field reads "colorless to white liquid to crystalline solid" — another material sitting on a state boundary, except this one's boundary is near body temperature rather than room temperature.

And its solubility field unusually gives use levels outright:

Fine fragrances: traces – 0.1%; shampoo: traces – 0.1%; shower gel: traces – 0.1%; soap: traces – 0.1%

Four product types, the same range, and the ceiling is 0.1%. That field is usually empty or lists only solvents; giving percentages is rare (ethyl maltol is the other example).

Together with "evaluate at 1% or less", the direction is consistent: this is a material that works at trace levels.

How to use it

• Make a 1% solution or weaker first. The field says so, and its strength rank is 3.
• Think of 0.1% as the ceiling in a finished product. The solubility field supplies that number itself.
• Do not expect civet absolute's animalic character from it. Its odour type is musk and its first word is clean. The urine and faecal notes come from other molecules.
• Weigh it and make a solution. A solid melting at 37.5 °C cannot be dropped.
• Watch the trade name. Firmenich's civettone and the database's (Z)-civet decenone are the same thing, and a catalogue may use either spelling.

What this doesn't establish

• I have not smelled it, or civet absolute. The whole article is fields, database-wide counts and three papers.
• The absolute's and the molecule's odour descriptions cannot be compared directly. The evaluation concentrations differ tenfold (10% versus 1%) and the solvents differ (IPM versus DPG). That is the biggest methodological limit here.
• "The animalic quality is not from civetone" is inferred from two odour fields. I have no compositional analysis of civet secretion and did not check which molecules contribute those words.
• Zero suppliers for the (E) isomer describes coverage, not that it is odourless or unsynthesisable. I did not look up its odour data.
• Callejo's team evaluated fluorinated analogues, not civetone itself. What that paper establishes is that ring conformation governs musk odour, not any property of civetone.
• Neither Shirasu nor Ahmed tested civetone. They tested muscone and other musk compounds; I place civetone in the macrocyclic ketone group on structural grounds, not on their data.
• All three toxicity fields are undetermined. That is the norm for 47.7% of well-supplied materials, not specific to this one.
• The percentages in the solubility field are supplier use recommendations, not regulatory limits. Check the IFRA standards separately.