Compounds · Alcohols · Terpenoid pathway
α-Santalol
Also known as (Z)-α-Santalol — an analysis may use any of these names
Cream, milk, soft wood. Sweet without sugar, warm without heat.
- CAS
- 115-71-9
- Formula
- C15H24O
- Molar mass
- 220.35
- Odour threshold
- —
- Boiling point
- ≈ 301 °C estimated
This compound boils at 301 °C, so it is heavier than any ordinary essential-oil component. It lies outside the 150–290 °C band, so the marker stops at the right edge — not because that is where it sits, but because the axis does not reach that far.
Must be declared on the label
This compound was added by Regulation (EU) 2023/1545 to the list of allergens that must be declared individually on cosmetic labels in the European Union. Name to use on the label: SANTALOL.
The declaration threshold is 0.001% in leave-on products and 0.01% in rinse-off products. This is an EU requirement — see the regulations page for why it matters beyond the EU. This is not legal advice.
Where it comes from
Biosynthetic pathway: Terpenoid pathway — plants build them from identical five-carbon blocks.
Why it sits where it does
A fifteen-carbon sesquiterpene alcohol with an extra hydroxyl group, so it is both large and polar. It is one of the heaviest components on the whole list and sits at the far right of the volatility band.
Where else you meet it
Sandalwood is almost its only source. Synthetic versions and substitutes are widely used because natural sandalwood is scarce and expensive.
Dictionary entries that mention this compound
About the boiling-point figure
Not cross-checked. Common sources give 166 °C, but that figure was almost certainly measured at reduced pressure — a fifteen-carbon molecule with a hydroxyl group cannot boil that low at atmospheric pressure. The value we use is an estimate based on structure. Why this detail matters