GREENS, HERBS AND FOUGERES / herbal · piney · fresh
Terpinolene
Category
GREENS, HERBS AND FOUGERES
Subcategory
herbal · piney · fresh
Origin
Volatility
Top Note
Botanical
Found in Melaleuca alternifolia (tea tree) / Pinus spp.
Appearance
Colorless clear liquid
Odor Strength
Medium
Producing Countries
Australia, China, United States
Pyramid
Top
Sweet pine sap on warm wood, with a lime-peel transparency and a faint anisic whisper. Not harsh or turpentine-like — softer and rounder than alpha-pinene, oilier than limonene, with a fleeting floral lift that vanishes in hours. The least abundant of the terpinene isomers, and the most pleasant.
Sweet and piney without the turpentine harshness of alpha-pinene. An oily, resinous warmth dominates the opening, immediately followed by a translucent lime-peel citrus note — not juicy, not zesty, more like dried lime rind left in a wooden bowl. Underneath, a faint anisic sweetness that Arctander identified as characteristic: not quite anise, not quite fennel, but a soft, round quality that prevents the pine from becoming aggressive.
Compared to gamma-terpinene (sharper, more terpenic, herbaceous), terpinolene is rounder and sweeter. Compared to limonene (bright, juicy, fruity), it is woodier and more resinous. The floral hint some evaluators describe as lilac-like is real but extremely faint — it registers as a texture rather than a note. On blotter, the molecule is largely gone after four hours, leaving only a faint, clean, woody-waxy trace.
Evolution over time
Immediately
Immediately
Sweet piney opening with oily warmth. Lime-peel citrus transparency. A faint anisic sweetness softens the terpenic attack. No turpentine harshness.
After a few hours
After a few hours
The pine recedes quickly. A brief woody-herbal phase with faint floral (lilac-like) undertone. The anisic quality becomes more apparent as the citrus fades. Mostly spent by hour three or four.
After a few days
After a few days
Virtually absent. A faint, clean, woody-waxy residue on fabric or blotter — barely perceptible. One of the least substantive monoterpenes in the perfumer’s palette.
The Full Story
CAS 586-62-9. Molecular formula C₁₀H₁₆, MW 136.24 g/mol. IUPAC: 1-methyl-4-(propan-2-ylidene)cyclohex-1-ene. A monocyclic monoterpene hydrocarbon — one of three terpinene isomers (alpha-terpinene, gamma-terpinene, terpinolene), differing only in the position of the two carbon-carbon double bonds within the p-menthane skeleton. Also known as delta-terpinene.
The scent is sweet, piney, and oily, with a particular anisic undertone that separates it from harsher terpene hydrocarbons. Arctander (1969) described it as ‘not nearly as harsh as pinene, often slightly anisic in its sweetness, and generally free from turpentine-like notes.’ There is a faint citrus transparency — lime peel rather than lemon juice — and a fleeting floral whisper that some evaluators compare to lilac. The overall impression is of warm pine resin cut with cold air. Substantivity is poor: approximately 4 hours on blotter at 100%, making it strictly a top-note material.
Natural Occurrence
Terpinolene occurs widely but as a minor constituent in most essential oils. In tea tree oil (Melaleuca alternifolia), it typically represents 1.5–3.5% of the volatile fraction. In parsley leaf oil (Petroselinum crispum), up to 8–13% depending on cultivar and harvest timing. In Moroccan pine oil (Pinus spp.), approximately 3.9%. Trace to minor amounts appear in cardamom, marjoram, cumin, coriander, basil, allspice, angelica root, juniper berry, ginger, nutmeg, bergamot, and blood orange oils. It is the least common of the terpinene isomers in most plant chemotypes — gamma-terpinene and alpha-terpinene are typically present at higher concentrations.
Production
Commercial terpinolene is produced primarily by acid-catalysed isomerization of alpha-pinene, sourced from sulfate turpentine (a waste stream of the paper pulp industry). Alpha-pinene treated with acid catalysts — mineral acids, zeolites, clays, or sulphonic acid resins — rearranges into a mixture of monocyclic products: limonene, alpha-terpinene, gamma-terpinene, terpinolene, and p-cymene, alongside bicyclic products (camphene, tricyclene). Terpinolene is separated by precision fractional distillation, collected in the 183–185°C boiling fraction. Commercial purity: 90–100%. The turpentine feedstock is renewable, making terpinolene a bio-based fragrance chemical.
Stability and Safety
Like all monoterpene hydrocarbons with allylic positions, terpinolene is susceptible to autoxidation upon air exposure. The resulting hydroperoxides and aldehydes can act as contact sensitizers — a concern shared with limonene, linalool, and alpha-terpinene. Fresh, properly stored material (sealed, cool, <24 months) shows no irritation or sensitization in human patch testing at 10% concentration. FEMA GRAS #3046. Oral LD₅₀ (rat): 4,390 mg/kg. Dermal LD₅₀ (rabbit): >5,000 mg/kg.
Steffen Arctander, the Danish-American perfumer whose 1969 reference work remains the industry standard, described terpinolene as 'sweet-piney, oily and relatively pleasant... not nearly as harsh as pinene, often slightly anisic in its sweetness, and generally free from turpentine-like notes.' That last distinction — a terpene that does not smell of turpentine — is precisely why it survives in pine formulations where cruder terpene fractions have been replaced by synthetics.
Extraction & Chemistry
Extraction method: Terpinolene is not extracted as a standalone natural product. It is obtained by two routes: (1) Fractional distillation of turpentine or coniferous essential oils, where it concentrates in the 183–185°C boiling fraction alongside other monoterpene hydrocarbons; (2) Acid-catalysed isomerization of alpha-pinene — the dominant industrial route — where alpha-pinene from sulfate turpentine is treated with acid catalysts (mineral acids, clays, zeolites, or sulphonic acid resins), producing a mixture of limonene, alpha-terpinene, gamma-terpinene, terpinolene, and camphene. Terpinolene is separated from this mixture by precision fractional distillation. Commercial material is typically 90–100% pure. The starting feedstock — turpentine — is a renewable byproduct of the paper pulp industry, making terpinolene bio-based.
Molecular Formula
C10 H16
CAS Number
586-62-9
Botanical Name
Found in Melaleuca alternifolia (tea tree) / Pinus spp.
IFRA Status
No IFRA restriction. FEMA GRAS #3046. TGSC recommends up to 50% in fragrance concentrate. No irritation or sensitization in human patch testing at 10%. However, like all monoterpene hydrocarbons, terpinolene autoxidizes on air exposure to form hydroperoxides — oxidized fractions may become skin sensitizers. Store sealed, cool, use within shelf life (24+ months).
Synonyms
ALPHA-TERPINOLENE · TERPINOLENE
Physical Properties
Odor Strength
Medium
Lasting Power
4 hour(s) at 100.00 %
Appearance
Colorless clear liquid
Boiling Point
183.00 to 185.00 °C. @ 760.00 mm Hg
Flash Point
148.00 °F. TCC ( 64.44 °C. )
Specific Gravity
0.88000 to 0.89000 @ 25.00 °C.
Refractive Index
1.46000 to 1.46400 @ 20.00 °C.
In Perfumery
Top-note modifier in pine, coniferous, and citrus-herbal compositions. Terpinolene functions primarily as a naturalness agent — it contributes the sweet, oily, resinous quality that makes synthetic pine accords smell more like actual conifers. In household fragrances (cleaners, deodorizers, pine-oil products), it is used at significant concentrations as a freshness builder and reodorant. In fine fragrance, its role is subtler: a background terpene that supports woody-green openings without imposing harshness. The molecule bridges pine and citrus registers. It sits between alpha-pinene (sharper, more turpentine-like) and limonene (brighter, more fruit-forward), offering a middle character that smooths terpenic compositions. It blends with other monoterpenes — gamma-terpinene, alpha-terpinene, terpinen-4-ol — in reconstructed tea tree, marjoram, and juniper accords. Its anisic sweetness (noted by Arctander) provides an unexpected bridge to herbaceous-aromatic notes like basil, tarragon, and fennel. TGSC recommends usage up to 50% in fragrance concentrate, though fine-fragrance applications rarely exceed 1–5%. Substantivity is poor — approximately 4 hours on blotter at 100% — limiting its role to top-note opening effects. Like all monoterpene hydrocarbons, terpinolene is susceptible to autoxidation on air exposure, forming peroxides and aldehydes that can become skin sensitizers. Freshness of the material matters.
