Alpha-Terpineol (CAS 98-55-5) — Floral Heart Note Fragrance Ingredient
Alpha-Terpineol
CAS 98-55-5
What Is Alpha-Terpineol?
Alpha-Terpineol is a naturally occurring alcohol found in many essential oils like pine and petitgrain. You’ll encounter its fresh, floral scent in household cleaners, soaps, and some perfumes. It’s also used as a flavoring agent in foods and beverages. This versatile ingredient matters because it bridges fresh and floral notes in fragrances, adding a clean, slightly woody character that enhances many modern compositions.
Safety Profile
GENERALLY SAFEWhat Does Alpha-Terpineol Smell Like?
Alpha-Terpineol opens with a crisp, pine-like freshness that quickly softens into a delicate floral heart reminiscent of lilacs with a hint of citrus. The dry-down reveals a subtle woody base with a clean, slightly soapy character. It behaves like a more refined version of pine oil – less sharp, more sophisticated, with excellent diffusion that makes it useful as a top-to-middle note. The scent evolves beautifully, starting fresh and outdoorsy before settling into a comforting, slightly powdery finish.
Scent Profile
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Alpha-Terpineol contributes to the authentic pine forest accord, softening the sharper terpenes with its floral-woody character.
Used here to bridge marine notes with woody base, adding a clean freshness that prevents the composition from becoming too sweet.
Provides a subtle floralcy that complements the citrus top notes while supporting the herbal heart of this classic cologne.
Alpha-Terpineol adds a refined greenness to the violet leaf accord, creating the impression of dewy morning grass.
Used sparingly here to brighten the floral bouquet and add a clean, slightly woody facet to this feminine favorite.
2D Molecular Structure
SMILES: CC1=CCC(CC1)C(C)(C)O
Chemistry, Properties & Perfumer Guide
The Chemistry
Alpha-Terpineol is a monoterpene alcohol (C10H17OH) that occurs naturally as a mixture of isomers in many plant essential oils. It’s typically synthesized from pinene via hydration or from limonene through acid-catalyzed reactions. The molecule contains a chiral center, with the (+)-isomer being more common in nature and generally considered more fragrant. Its tertiary alcohol structure makes it relatively stable compared to primary terpene alcohols. Industrial production often involves fractional distillation of byproducts from the paper industry’s sulfate turpentine process.
Physical & Chemical Properties
| Boiling Point | 218-219 °C |
|---|---|
| Melting Point | 35 °C |
| Flash Point | 96 °C |
| Density | 0.935 g/cm³ |
| Refractive Index | 1.482-1.485 |
| Vapor Pressure | 0.01 mmHg at 20°C |
| Solubility | Slightly soluble in water, miscible with alcohol and oils |
| Appearance | Colorless to pale yellow viscous liquid |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | Up to 5% | Adds fresh-floral lift to masculine compositions |
| Household Products | 0.5-2% | Up to 3% | Provides clean, pine-like freshness |
| Soaps/Detergents | 0.2-1% | Up to 1.5% | Contributes to fresh linen-type scents |
| Flavorings | 10-100 ppm | Up to 200 ppm | Used in citrus and spice flavor profiles |
Classic Accords
Tip: Use alpha-terpineol to soften harsh terpenic notes while maintaining freshness – especially effective in fougère and chypre bases.
Alternatives & Comparisons
For a less floral, more herbal-terpenic character with similar fresh qualities but lower tenacity.
When more pronounced floralcy is desired, though it lacks alpha-terpineol’s woody dimension.
Provides similar fresh-green effects but with more citrusy, aldehydic character.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. IFRA, REACH, EU Cosmetics Regulation standards update periodically. Consult current IFRA Standards Library before formulating. Not legal or regulatory advice.
IFRA Status
Not restricted under IFRA standards. Considered safe for use in all fragrance categories at current usage levels.
EU Allergen Declaration
Not listed as an EU-regulated fragrance allergen.
GHS Classification
RIFM Assessment
RIFM evaluation confirms safe use at current industry levels, with no evidence of phototoxicity or significant sensitization potential.
Sustainability
Alpha-Terpineol is increasingly produced via sustainable routes from paper industry byproducts. Synthetic production has lower environmental impact than extraction from natural sources. Biodegradability is excellent (OECD 301D), and it’s not considered bioaccumulative. Most commercial material is now derived from turpentine, a renewable forest product.
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References
- Bickers et al. (2003). Safety assessment of alpha-terpineol. Food and Chemical Toxicology. PubChem CID 443162
- IFRA Standards Library (2023). 49th Amendment. IFRA Standards
- Sell C. (2006). The Chemistry of Fragrances. RSC Publishing. DOI: 10.1039/9781847555400
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Mar 2026.
Report a data errorIngredient Data Sheet
CAS 98-55-5Physical Properties
| Molecular Weight | 154.25 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.8🔬 PubChem |
| Boiling Point | 219.5 °C🔬 EPA CompTox |
| Vapor Pressure | 0.04 mmHg @ 25°C📊 OPERA |
| Flash Point | 91 °C🔬 EPA CompTox |
| Involatility Index | 0.0035💻 Calculated |
| log Kp (skin permeability) | -2.363💻 Calculated |
| SMILES | CC1=CCC(CC1)C(C)(C)O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 2.1 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | floralsweet• leffingwell |
| Functional Groups | alcoholalkene💻 RDKit |
| “The odor of high-grade alpha-Terpineol being delicately floral and sweet of Lilac type, it is very strongly influenced in presence of minute amounts of impurities of different odor type. The most common undesirable odors are the more volatile terpenes and terpene alcohols (see l-Terpinenol) and the less volatile phenols, often occurring in traces in "European type" Terpineol. beta-Terpineol is the main impurity among the more volatile ones.”📖 Arctander | |
Flavor Notes (Arctander)
| “Very slightly soluble in water, soluble in alcohol, Propylene glycol, Mineral oil and perfume and flavor materials. Terpineol for flavor purpose should be of equally high olfactory (organoleptic) purity, except perhaps for Lime flavors, where certain qualities, unacceptable for a Lilac perfume, will”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.4995 ppm (n=23)📖 van Gemert |
Regulatory Status
| EU Annex III | Listed (restricted)⚖️ IFRA 51 |
| FEMA Number | FEMA 3045⚖️ FEMA GRAS |
| GRAS Status | Generally Recognized as Safe⚖️ FEMA GRAS |
Trade Names
| Mayol®(Firmenich).📖 Surburg |
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.
Physicochemical Properties
DTXSID: DTXSID5026625
Physical Properties
| Molecular Weight | 154.253 g/mol🔬 EPA CompTox |
| Density | 0.935 g/cm^3🔬 EPA CTX |
| Boiling Point | 219.313 °C🔬 EPA CTX |
| Melting Point | 32.875 °C🔬 EPA CTX |
| Flash Point | 91.62 °C🔬 EPA CTX |
| Refractive Index | 1.483 Dimensionless📊 OPERA |
| Molar Volume | 164.977 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.036 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.008 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.008 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.16 Log10 unitless📊 OPERA |
| Water Solubility | 0.011 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.035 mmHg🔬 EPA CTX |
| Viscosity | 6.906 cP📊 OPERA |
| Surface Tension | 31.946 dyn/cm📊 OPERA |
| Thermal Conductivity | 130.808 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 20.23 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 47.075 cm^3/mol📊 OPERA |
| Polarizability | 18.662 Å^3📊 OPERA |
Data Sources:
🔬 EPA Experimental data from U.S. EPA CompTox Chemicals Dashboard & CTX APIs. 📊 OPERA Predicted using EPA's OPERA QSAR models. 💻 Computed Calculated from SMILES using RDKit.
