Compounds · Sesquiterpenes · Terpenoid pathway
Germacrene D
Wood, slightly spicy, with a faint earthy note. Hard to pick out because it is rarely alone.
- CAS
- 23986-74-5
- Formula
- C15H24
- Molar mass
- 204.36
- Odour threshold
- —
- Boiling point
- ≈ 275 °C estimated
Where it comes from
Biosynthetic pathway: Terpenoid pathway — plants build them from identical five-carbon blocks.
Why it sits where it does
Its ten-membered ring is very flexible, and it is the biological precursor of many other sesquiterpenes. It is also unstable to heat: during distillation part of it turns into other compounds.
Where else you meet it
Widespread across the plant kingdom, usually at a few per cent. It is one of the most common sesquiterpenes on an analysis.
About the boiling-point figure
Boiling points of heavy molecules are often published at reduced pressure without the pressure being stated, because at atmospheric pressure many of them decompose before they boil. The value here is an estimate converted to atmospheric pressure, used to place the compound on the volatility axis, not a measurement. Why this detail matters