Compound library · Chemical families
Chemical families
Boiling point tells you when you smell a compound. Chemical family tells you how it behaves: stable or fragile, strong or soft, and why one bottle still smells good six months after opening while another has already turned sour.
The least stable. With no functional group, they oxidise easily into heavier alcohols and ketones.
Limonene · γ-Terpinene · Myrcene
Considerably more stable than monoterpenes thanks to their tight ring structures.
α-Humulene · β-Caryophyllene · Longifolene
Fairly stable. An alcohol is already an oxidised form, so it degrades little further.
1-Octen-3-ol · Geosmin · Linalool
Chemically very stable. The conjugated aromatic ring stabilises the molecule, so phenol-rich oils are among those that keep their smell longest.
Eugenol · Guaiacol · Syringol
Unstable. Aldehydes oxidise further into acids, and some polymerise on long exposure to air.
Furfural · Decanal · 5-Methylfurfural
Much more stable than aldehydes. The carbonyl in the middle of the chain is shielded on both sides, so it is hard to oxidise further.
Camphor · Carvone · Diacetyl
Easily hydrolysed in the presence of water and heat, splitting back into alcohol and acid.
Benzyl acetate · Ethyl butanoate · Isoamyl acetate
Fairly stable. The ether ring does not open easily under ordinary conditions.
1,8-Cineole · Caryophyllene oxide
More stable than open-chain esters, because the closed ring is harder to hydrolyse.
γ-Nonalactone · δ-Decalactone · Coumarin
Very variable. Sulphur compounds are usually unstable and easily transformed; aromatic nitrogen compounds are very stable.
2-Acetyl-1-pyrroline · Furaneol · Acetic acid
The order above follows chemical structure: the two terpene families first, then functional groups from simple to complex. Stability does not follow that order — very stable phenols sit right before fragile aldehydes. Each family page goes into detail: structure, evaporation behaviour, how to recognise it on an analysis, and the boiling-point range of its compounds in the library.