2-Methylnaphthalene (CAS 91-57-6) — Woody Base Note Fragrance Ingredient
2-Methylnaphthalene
CAS 91-57-6
What Is 2-Methylnaphthalene?
2-Methylnaphthalene is a synthetic aromatic compound primarily used in industrial applications and some niche fragrances. It’s rarely encountered directly by consumers but may appear in complex woody or smoky accords. This ingredient matters because it contributes depth and persistence to fragrance bases, though its use requires careful formulation due to its potent nature.
Safety Profile
USE WITH AWARENESSWhat Does 2-Methylnaphthalene Smell Like?
2-Methylnaphthalene presents a sharp, medicinal aroma with pronounced tar-like and coal-derived characteristics. The opening is intensely chemical with rubbery undertones, evolving into a dry, woody heart with hints of mothballs and old books. The dry-down reveals persistent smoky facets that linger with an almost asphalt-like tenacity. When diluted, it can contribute earthy, leathery nuances to complex accords.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used sparingly to enhance the dark, resinous character with its industrial smokiness, contributing to the fragrance’s notorious asphalt-like edge.
Provides an acrid, burnt note that contrasts with traditional barbershop elements, creating the signature ‘burning’ effect.
2D Molecular Structure
SMILES: CC1=CC2=CC=CC=C2C=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Methylnaphthalene belongs to the polycyclic aromatic hydrocarbon (PAH) class, structurally related to naphthalene but with an additional methyl group. It’s produced through coal tar distillation or petroleum refining. The methyl substitution increases its volatility compared to naphthalene while maintaining aromatic stability. Its planar structure allows for strong π-π interactions with olfactory receptors.
Physical & Chemical Properties
| Boiling Point | 241-243 °C |
|---|---|
| Melting Point | 34-36 °C |
| Density | 1.005 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Used for smoky, industrial effects |
| Functional Fragrance | Not used | N/A | Generally avoided due to safety concerns |
Classic Accords
Tip: Always use below 1% and combine with smoothing agents like vanillin to tame harsh edges.
Alternatives & Comparisons
Similar aromatic profile but slightly less harsh, with marginally better safety profile for fragrance use.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA but use discouraged due to potential sensitization concerns.
GHS Classification
RIFM Assessment
RIFM recommends limited use due to insufficient safety data and potential sensitization risks.
Sustainability
As a petroleum-derived synthetic, 2-methylnaphthalene raises environmental concerns regarding fossil fuel dependence. Production generates hazardous waste streams requiring careful management. Some manufacturers are exploring bio-based synthesis routes to reduce environmental impact.
Explore 2-Methylnaphthalene
Browse essential oils and aroma compounds.
Browse on iHerb →Affiliate disclosure: we may earn a small commission at no extra cost to you.
References
- National Center for Biotechnology Information. PubChem Compound Summary for CID 7057, 2-Methylnaphthalene. PubChem CID 7057
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 91-57-6Physical Properties
| Molecular Weight | 142.2 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.9🔬 PubChem |
| Boiling Point | 241.1 °C🔬 EPA CompTox |
| Vapor Pressure | 0.05 mmHg @ 25°C📊 OPERA |
| Flash Point | 97.8 °C🔬 EPA CompTox |
| Involatility Index | 0.0045💻 Calculated |
| log Kp (skin permeability) | -0.798💻 Calculated |
| SMILES | CC1=CC2=CC=CC=C2C=C1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 2.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | herbal• leffingwell |
| Functional Groups | aromatic💻 RDKit |
Sensory Thresholds
| Odor Detection Threshold | 0.0049 ppm (n=3)📖 van Gemert |
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: DTXSID4020878
Physical Properties
| Molecular Weight | 142.201 g/mol🔬 EPA CompTox |
| Density | 1.005 g/cm^3🔬 EPA CTX |
| Boiling Point | 241.339 °C🔬 EPA CTX |
| Melting Point | 34.095 °C🔬 EPA CTX |
| Flash Point | 97.761 °C🔬 EPA CTX |
| Refractive Index | 1.617 Dimensionless📊 OPERA |
| Molar Volume | 139.824 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.873 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.897 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.897 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.83 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.013 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.055 mmHg🔬 EPA CTX |
| Viscosity | 3.717 cP📊 OPERA |
| Surface Tension | 37.931 dyn/cm📊 OPERA |
| Thermal Conductivity | 125.56 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 | 2 count💻 Computed |
| Molar Refractivity | 48.92 cm^3/mol📊 OPERA |
| Polarizability | 19.394 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.
![Methyl 3,3-dimethylbicyclo[2.2.1]heptane-2-carboxylate (CAS 52557-97-8) — Woody Middle Note Fragrance Ingredient](https://thegoodscents.company/wp-content/uploads/2026/04/methyl-3-3-dimethylbicyclo-2-2-1-heptane-2-carboxylate-1-768x439.webp)
