Methyl octadecanoate (CAS 112-61-8) — Woody Base Note Fragrance Ingredient
Methyl octadecanoate
CAS 112-61-8
What Is Methyl octadecanoate?
Methyl octadecanoate is a synthetic ester commonly used as a fixative in perfumes and a base note in soaps. It provides subtle waxy, fatty undertones that help blend other fragrance components. Though not a star ingredient, it plays a crucial supporting role by extending scent longevity and smoothing harsh edges in compositions.
Safety Profile
GENERALLY SAFEWhat Does Methyl octadecanoate Smell Like?
Methyl octadecanoate presents a faint, clean waxy character reminiscent of candle wax or cosmetic bases. Its odor profile is intentionally subtle – acting more as a textural element than an aromatic one. The molecule provides a smooth, slightly fatty foundation that helps anchor brighter notes without introducing its own distinct scent. Over time, it contributes to a soft skin-like dry-down effect.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a background fixative to help blend the complex floral bouquet and extend wear time without altering the signature scent profile.
Employed in the base to smooth the transition between vanilla and leather accords, adding subtle waxiness to the oriental composition.
2D Molecular Structure
SMILES: CCCCCCCCCCCCCCCCCC(=O)OC
Chemistry, Properties & Perfumer Guide
The Chemistry
Methyl octadecanoate (methyl stearate) is a saturated fatty acid methyl ester derived from stearic acid. Industrially produced through esterification of stearic acid with methanol, often using acid catalysts. As a long-chain ester, it exhibits low volatility and good stability. The straight 18-carbon chain contributes to its waxy character and fixative properties.
Physical & Chemical Properties
| Appearance | White crystalline solid |
|---|---|
| Melting Point | 37-39 °C |
| Boiling Point | 442 °C |
| Density | 0.85 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-3% | Up to 5% | Fixative and smoothing agent |
| Soaps | 1-5% | Up to 8% | Adds creaminess to formulations |
Classic Accords
Tip: Use to round out sharp woody or amber notes while adding subtle fixation.
Alternatives & Comparisons
Shorter chain length provides slightly more diffusion while maintaining similar waxy character. Useful when more lift is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions apply to methyl octadecanoate.
RIFM Assessment
RIFM evaluation finds no significant safety concerns at current usage levels.
Sustainability
Synthetic production from renewable plant-derived stearic acid offers consistent quality and avoids agricultural impacts. Biodegradability is moderate due to ester structure. Preferred over animal-derived fixatives for ethical sourcing.
Explore Methyl octadecanoate
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090772
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 112-61-8Physical Properties
| Molecular Weight | 298.5 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 9🔬 PubChem |
| Boiling Point | 442.2 °C🔬 EPA CompTox |
| Vapor Pressure | 0 mmHg @ 25°C📊 OPERA |
| Flash Point | 152.8 °C🔬 EPA CompTox |
| log Kp (skin permeability) | 1.869💻 Calculated |
| SMILES | CCCCCCCCCCCCCCCCCC(=O)OC🔬 PubChem |
Volatility & Performance
| Fragrance Note | Base💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 18.3 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | odorless• leffingwell |
| Functional Groups | esterether💻 RDKit |
| “This ester finds a little use in perfume formulations as a blender/modifier or diluent of very little odor value. It may contribute a faint, oily note to flower bases, and it may be useful as an Oakmoss extract solvent, but beyond these and a few other uses, the material is not needed in a perfume laboratory.”📖 Arctander | |
Flavor Notes (Arctander)
| “Practically tasteless, but imparts an oily mouthfeel without being fatty or greasy.”📖 Arctander |
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: DTXSID2047640
Physical Properties
| Molecular Weight | 298.511 g/mol🔬 EPA CompTox |
| Density | 0.849 g/cm^3📊 OPERA |
| Boiling Point | 392.775 °C🔬 EPA CTX |
| Melting Point | 39.286 °C🔬 EPA CTX |
| Flash Point | 129.854 °C🔬 EPA CTX |
| Refractive Index | 1.444 Dimensionless📊 OPERA |
| Molar Volume | 345.646 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 8.35 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 8.466 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 8.466 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 9.41 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.006 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0 mmHg🔬 EPA CTX |
| Viscosity | 6.869 cP📊 OPERA |
| Surface Tension | 29.94 dyn/cm📊 OPERA |
| Thermal Conductivity | 151.312 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 26.3 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 16 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 91.848 cm^3/mol📊 OPERA |
| Polarizability | 36.411 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.
