l-.alpha.-Pinene (CAS 7785-26-4) — Woody Top Note Fragrance Ingredient
l-.alpha.-Pinene
CAS 7785-26-4
What Is l-.alpha.-Pinene?
α-Pinene is a natural compound found in pine trees and many other plants. It’s what gives pine forests their fresh, resinous scent. You encounter it in cleaning products, air fresheners, and some perfumes. This ingredient matters because it’s one of the most common terpenes in nature, contributing to both fragrance and potential therapeutic effects.
Safety Profile
GENERALLY SAFEWhat Does l-.alpha.-Pinene Smell Like?
α-Pinene smells like walking through a sun-warmed pine forest – crisp, clean, and slightly sharp with a woody-green character. The top note is bright and camphoraceous, evolving into a drier, more resinous heart. In drydown, it leaves a subtle woody trail that blends well with other forest notes.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Uses α-pinene to create its iconic pine forest accord, giving the fragrance its fresh, masculine opening.
Incorporates α-pinene for its green, uplifting top notes that complement the fruity-floral heart.
2D Molecular Structure
SMILES: CC1=CC[C@H]2C[C@@H]1C2(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
α-Pinene is a bicyclic monoterpene with the formula C₁₀H₁₆. It exists in two enantiomers: (+)-α-pinene from pine trees and (-)-α-pinene from turpentine. Industrially produced via fractional distillation of turpentine oil or synthesized from β-pinene. The molecule’s strained ring structure makes it reactive in air oxidation.
Physical & Chemical Properties
| Boiling Point | 155-156 °C |
|---|---|
| Density | 0.858 g/cm³ |
| Refractive Index | 1.465 |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | Fresh top notes |
| Functional Fragrance | 5-15% | Up to 25% | Cleaning products |
Classic Accords
Tip: Use to add natural, outdoorsy freshness to masculine and unisex fragrances.
Alternatives & Comparisons
Similar but with a warmer, less sharp character – good when you want softer pine notes.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under IFRA standards.
RIFM Assessment
Considered safe as used in fragrance by RIFM.
Sustainability
Most α-pinene is sourced as a byproduct of paper production from pine trees, making it relatively sustainable. Synthetic production exists but is less common. The compound is biodegradable and doesn’t persist in the environment.
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References
- PubChem: α-Pinene CID 6654
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID2029290
Physical Properties
| Molecular Weight | 136.238 g/mol🔬 EPA CompTox |
| Density | 0.001 g/cm^3🔬 EPA CTX |
| Boiling Point | 154.957 °C🔬 EPA CTX |
| Melting Point | -61.5 °C🔬 EPA CTX |
| Flash Point | 31.15 °C🔬 EPA CTX |
| Refractive Index | 1.479 Dimensionless📊 OPERA |
| Molar Volume | 154.905 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 10226.322 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 4.484 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.484 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.44 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.135 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 4.86 mmHg🔬 EPA CTX |
| Viscosity | 1.679 cP📊 OPERA |
| Surface Tension | 27.057 dyn/cm📊 OPERA |
| Thermal Conductivity | 114.426 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 0 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 0 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 43.964 cm^3/mol📊 OPERA |
| Polarizability | 17.429 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.
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