l-Menthol (CAS 2216-51-5) — Citrus Top-Middle Note Fragrance Ingredient
l-Menthol
CAS 2216-51-5
What Is l-Menthol?
l-Menthol is the naturally occurring form of menthol, most commonly associated with the cooling sensation in peppermint and mint products. You’ll encounter it in chewing gum, toothpaste, cough drops, and topical pain relievers. This enantiomer provides superior cooling effects compared to synthetic racemic mixtures, making it prized in both flavor and fragrance applications.
Safety Profile
GENERALLY SAFEWhat Does l-Menthol Smell Like?
l-Menthol bursts with an intense, crystalline freshness – like Arctic wind blowing through a peppermint field. The initial sensation is sharply cooling, almost painful in its purity, before mellowing into a rounded herbal sweetness. Unlike synthetic menthols, it maintains a clean, natural character throughout evaporation without chemical harshness. The dry-down reveals subtle woody undertones that prevent the cooling effect from becoming clinical or medicinal.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used sparingly to amplify the aquatic freshness with its natural cooling properties, creating the illusion of ocean breezes without overt mintiness.
Provides subtle cooling contrast to the violet leaf and iris, enhancing the dew-on-grass freshness of this classic fougère.
2D Molecular Structure
SMILES: CC(C)[C@@H]1CC[C@@H](C)C[C@H]1O
Chemistry, Properties & Perfumer Guide
The Chemistry
l-Menthol is a monoterpenoid alcohol with three chiral centers, occurring naturally in Mentha arvensis and other mint species. The (-)-menthol enantiomer binds preferentially to TRPM8 cold receptors, explaining its superior cooling effect. Industrial production typically involves hydrogenation of thymol or resolution of racemic menthol mixtures. The L-form crystallizes in characteristic hexagonal plates due to its specific molecular geometry.
Physical & Chemical Properties
| Melting Point | 42-45 °C |
|---|---|
| Boiling Point | 212 °C |
| Optical Rotation | -50° (c=10, ethanol) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Cooling accent |
| Functional Fragrance | 0.5-2% | Up to 5% | Freshness booster |
Classic Accords
Tip: Balance cooling effects with warm base notes to prevent fragrance from feeling clinical.
Alternatives & Comparisons
Less expensive but weaker cooling effect; use when cost is prioritized over performance.
Synthetic coolant without mint odor for applications requiring pure cooling sensation.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions. Approved for all fragrance categories.
RIFM Assessment
Considered safe for current use levels in fragrance applications.
Sustainability
Most l-menthol is now produced synthetically from renewable turpentine feedstocks, reducing pressure on wild mint populations. The L-enantiomer’s higher potency means less material is required compared to racemic mixtures, improving sustainability metrics.
Explore l-Menthol
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References
- Eccles R. (1994). Menthol and related cooling compounds. Journal of Pharmacy and Pharmacology. PMID 7932039
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID1022180
Physical Properties
| Molecular Weight | 156.269 g/mol🔬 EPA CompTox |
| Density | 0.49 g/cm^3🔬 EPA CTX |
| Boiling Point | 214.254 °C📊 OPERA |
| Melting Point | 42.931 °C🔬 EPA CTX |
| Flash Point | 92.825 °C🔬 EPA CTX |
| Refractive Index | 1.457 Dimensionless📊 OPERA |
| Molar Volume | 175.542 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.256 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.242 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.242 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.6 Log10 unitless📊 OPERA |
| Water Solubility | 0.003 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.12 mmHg🔬 EPA CTX |
| Viscosity | 9.449 cP📊 OPERA |
| Surface Tension | 29.625 dyn/cm📊 OPERA |
| Thermal Conductivity | 129.72 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 | 47.833 cm^3/mol📊 OPERA |
| Polarizability | 18.963 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.
