Heptanoic acid, octadecyl ester (CAS 66009-41-4) — Woody Base Note Fragrance Ingredient

Woody · Sweet

Heptanoic acid, octadecyl ester

CAS 66009-41-4

Origin
synthetic
Note
Base
IFRA
Generally safe
Data as of: Apr 2026

What Is Heptanoic acid, octadecyl ester?

Heptanoic acid, octadecyl ester is a synthetic fragrance ingredient primarily used in industrial and functional fragrance applications. It’s found in some cleaning products and air fresheners where subtle odor modification is needed. This ester contributes to creating smooth, slightly fatty olfactory effects that help round out harsh chemical notes in functional products.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
Low toxicity profile
No known allergen status
CAS
66009-41-4
Formula
Mixture
MW
Variable
Odor Family
Woody · Sweet
Layer 1 · Enthusiast

What Does Heptanoic acid, octadecyl ester Smell Like?

This ester presents a mild, waxy odor profile with subtle fatty undertones reminiscent of candle wax or clean paraffin. The scent evolves minimally over time, maintaining a stable, unobtrusive character that serves primarily as a background modifier rather than a dominant note. In dilution, it can impart a faintly soapy-clean impression that helps soften sharper chemical odors in functional formulations.

Scent Profile
Layer 2

2D Molecular Structure

Octadecyl heptanoate

SMILES: CCCCCCCCCCCCCCCCCCOC(=O)CCCCCC

Chemistry, Properties & Perfumer Guide

The Chemistry

Heptanoic acid, octadecyl ester is a synthetic ester formed from heptanoic acid and octadecanol. As a long-chain ester, it exhibits low volatility and relatively weak odor intensity compared to shorter-chain esters. The molecule’s stability makes it useful for functional applications requiring odor persistence. Production typically involves acid-catalyzed esterification under controlled conditions.

Physical & Chemical Properties

Perfumer Guide

Note Position
Base
Volatility
Very low (persistent)
Blending
Functional
ApplicationTypical %RangeNotes
Functional Fragrances0.5-2%Up to 5%Background modifier
Cleaning Products0.1-1%Up to 3%Odor smoothing agent

Classic Accords

Tip: Use as a subtle modifier to reduce harshness in detergent bases.

Alternatives & Comparisons

1
Stearic acid CAS 57-11-4

For similar fatty character with higher stability in soap applications.

2
Ethyl heptanoate CAS 106-30-9

When a more volatile ester with fruity notes is preferred.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

General reference only. Consult current IFRA Standards Library before formulating.

IFRA Status

Not restricted by IFRA

RIFM Assessment

No specific RIFM assessment found for this ester.

Sustainability

As a synthetic material, this ester is produced from petrochemical feedstocks. Its environmental impact is comparable to other synthetic esters used in fragrance applications. The long carbon chain provides biodegradability potential, though specific ecotoxicity data is limited for this particular ester.

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References

    Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.

    Report a data error

    Perfumer’s Notes

    MW: 382.7

    LogP: 11.4

    Ingredient Data Sheet

    CAS 66009-41-4

    Physical Properties

    Molecular Weight382.7 g/mol🔬 PubChem
    LogP (Octanol-Water)11.4🔬 PubChem
    Boiling Point425 °C🔬 EPA CompTox
    Vapor Pressure0 mmHg @ 25°C📊 OPERA
    Flash Point217.8 °C🔬 EPA CompTox
    log Kp (skin permeability)3.06💻 Calculated
    SMILESCCCCCCCCCCCCCCCCCCOC(=O)CCCCCC🔬 PubChem

    Volatility & Performance

    Fragrance NoteBase💻 Calculated
    Volatility ClassVery slow💻 Calculated
    Persistence Score27.3 / 5💻 Calculated

    Odor & Flavor

    Functional Groupsesterether💻 RDKit
    Data Sources & Attribution
    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: DTXSID9070379

    Physical Properties

    Molecular Weight 382.673 g/mol🔬 EPA CompTox
    Density 0.833 g/cm^3📊 OPERA
    Boiling Point 414.699 °C📊 OPERA
    Melting Point 39.436 °C📊 OPERA
    Flash Point 207.292 °C📊 OPERA
    Refractive Index 1.451 Dimensionless📊 OPERA
    Molar Volume 444.686 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 10.351 Log10 unitless📊 OPERA
    LogD (pH 5.5) 10.351 Log10 unitless📊 OPERA
    LogD (pH 7.4) 10.351 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 11.74 Log10 unitless📊 OPERA
    Water Solubility 0 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0 mmHg📊 OPERA
    Viscosity 13.2 cP📊 OPERA
    Surface Tension 30.618 dyn/cm📊 OPERA
    Thermal Conductivity 154.643 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 22 count💻 Computed
    Aromatic Rings 0 count💻 Computed
    Molar Refractivity 119.645 cm^3/mol📊 OPERA
    Polarizability 47.431 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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