Octadecane (CAS 593-45-3) — Woody Base Note Fragrance Ingredient
Octadecane
CAS 593-45-3
What Is Octadecane?
Octadecane is a synthetic hydrocarbon commonly used as a base or fixative in perfumes and candles. It helps slow the evaporation of more volatile fragrance components. This ingredient matters because it extends the longevity of scents without adding its own strong odor, making it a versatile tool in fragrance formulation.
Safety Profile
GENERALLY SAFEWhat Does Octadecane Smell Like?
Octadecane is nearly odorless, with only the faintest waxy, paraffin-like character detectable at high concentrations. It serves primarily as a neutral foundation rather than an active scent contributor. In formulations, it provides subtle texture – a clean, slightly mineralic backdrop that helps bind volatile top notes and smooth transitions between fragrance phases without distorting the intended olfactory profile.
2D Molecular Structure
SMILES: CCCCCCCCCCCCCCCCCC
Chemistry, Properties & Perfumer Guide
The Chemistry
Octadecane is a straight-chain alkane with 18 carbon atoms (C18H38), classified as a hydrocarbon. It’s produced through petroleum distillation or Fischer-Tropsch synthesis. As a saturated hydrocarbon, it’s chemically inert and stable across a wide temperature range. The molecule lacks functional groups, contributing to its neutral odor profile and making it useful as an odorless diluent or solvent in fragrance applications.
Physical & Chemical Properties
| Boiling Point | 317 °C |
|---|---|
| Melting Point | 28-30 °C |
| Flash Point | >110 °C |
| Density | 0.777 g/cm³ (20 °C) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | Fixative/base component |
| Candles | 5-15% | Up to 20% | Wax compatibility modifier |
| Functional Products | 0.5-3% | Up to 5% | Solvent/fixative |
Classic Accords
Tip: Use to extend longevity of citrus or light floral fragrances without altering their character.
Alternatives & Comparisons
Shorter chain length provides slightly higher volatility while maintaining neutral odor profile.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions apply to octadecane.
RIFM Assessment
RIFM considers octadecane safe for current fragrance use levels based on extensive hydrocarbon data.
Sustainability
As a petroleum-derived material, octadecane’s sustainability depends on feedstock sourcing and production methods. Some manufacturers offer bio-based versions synthesized from renewable resources. Its chemical stability means it doesn’t contribute to VOC emissions or atmospheric reactivity, though biodegradation is slow in natural environments.
Explore Octadecane
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References
- PubChem Compound Summary for Octadecane PubChem CID 11607
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorLayer 3 · Practical
- Odor Profile: gasoline, waxy
- Molecular Weight: 254.50 g/mol
- LogP (XLogP): 9.30
Ingredient Data Sheet
CAS 593-45-3Physical Properties
| Molecular Weight | 254.5 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 9.3🔬 PubChem |
| Boiling Point | 316.1 °C🔬 EPA CompTox |
| Vapor Pressure | 3.41 mmHg @ 25°C📊 OPERA |
| Flash Point | 100 °C🔬 EPA CompTox |
| Involatility Index | 0.2304💻 Calculated |
| log Kp (skin permeability) | 2.351💻 Calculated |
| SMILES | CCCCCCCCCCCCCCCCCC🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Moderate💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | waxy• leffingwell |
Sensory Thresholds
| Odor Detection Threshold | 0.02 ppm📖 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: DTXSID9047172
Physical Properties
| Molecular Weight | 254.502 g/mol🔬 EPA CompTox |
| Density | 0.777 g/cm^3🔬 EPA CTX |
| Boiling Point | 316.353 °C🔬 EPA CTX |
| Melting Point | 28.092 °C🔬 EPA CTX |
| Flash Point | 142.356 °C🔬 EPA CTX |
| Refractive Index | 1.438 Dimensionless📊 OPERA |
| Molar Volume | 325.657 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 8.84 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 9.487 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 9.487 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.93 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 3.09 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0 mmHg🔬 EPA CTX |
| Viscosity | 3.424 cP📊 OPERA |
| Surface Tension | 27.164 dyn/cm📊 OPERA |
| Thermal Conductivity | 142.574 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 | 15 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 85.44 cm^3/mol📊 OPERA |
| Polarizability | 33.871 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.
