Amyl butyrate (CAS 540-18-1) — Sweet Top Note Fragrance Ingredient
Amyl butyrate
CAS 540-18-1
What Is Amyl butyrate?
Amyl butyrate is a synthetic ester used in perfumery for its fruity, banana-like aroma. You’ll encounter it in fruity fragrances, flavored foods, and some household products. It’s prized for its ability to add realistic, juicy fruit notes without the complexity of natural extracts.
Safety Profile
GENERALLY SAFEWhat Does Amyl butyrate Smell Like?
Amyl butyrate bursts with an intensely sweet, overripe banana aroma that quickly settles into a juicy pear and pineapple heart. The top note has a slightly boozy, fermented quality like banana liqueur, while the dry-down reveals a softer, creamier aspect reminiscent of custard or whipped cream. In dilution, it can suggest tropical fruits like guava or passionfruit with a subtle green nuance.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used for its hyper-sweet fruity punch that defines the fragrance’s candy-like opening, contrasting with floral and woody base notes.
Contributes to the licorice-anise top note illusion with its banana-like sweetness that blends seamlessly with herbal elements.
2D Molecular Structure
SMILES: CCCCCOC(=O)CCC
Chemistry, Properties & Perfumer Guide
The Chemistry
Amyl butyrate (pentyl butanoate) is an ester formed from butyric acid and amyl alcohol. Industrially produced via Fischer esterification, this simple molecule delivers disproportionate olfactory impact due to its low odor threshold. The straight-chain structure gives it cleaner fruity character compared to branched-chain esters. While naturally occurring in some fruits like bananas and pineapples, commercial production is entirely synthetic for consistency and cost efficiency.
Physical & Chemical Properties
| Boiling Point | 185-186 °C |
|---|---|
| Density | 0.866 g/cm³ |
| Refractive Index | 1.411 |
| Flash Point | 62 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used for fruity top notes |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Adds fruity freshness to cleaners |
| Flavor | 10-50 ppm | Up to 100 ppm | Banana and fruit flavor enhancer |
Classic Accords
Tip: Use in trace amounts with citrus oils to prevent candy-like overdose in fresh fragrances.
Alternatives & Comparisons
Offers sharper, greener banana note when more naturalistic fruit effect is desired, though less sweet and persistent.
Provides similar tropical fruit character but with added floral and metallic nuances for more sophisticated applications.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted under current IFRA standards (Amendment 49).
RIFM Assessment
RIFM evaluation confirms safe use at current levels in fragrance applications.
Sustainability
As a petrochemical-derived synthetic, amyl butyrate’s environmental impact comes from fossil fuel feedstock. However, its high potency means minimal quantities are needed compared to natural extracts. Some manufacturers are exploring bio-based production routes using fermentation-derived alcohols.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090860
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID4041604
Physical Properties
| Molecular Weight | 158.241 g/mol🔬 EPA CompTox |
| Density | 0.865 g/cm^3🔬 EPA CTX |
| Boiling Point | 186.2 °C🔬 EPA CTX |
| Melting Point | -73.2 °C🔬 EPA CTX |
| Flash Point | 65.687 °C🔬 EPA CTX |
| Refractive Index | 1.418 Dimensionless📊 OPERA |
| Molar Volume | 180.578 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.32 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.215 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.215 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.45 Log10 unitless📊 OPERA |
| Water Solubility | 0.002 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.001 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.817 mmHg🔬 EPA CTX |
| Viscosity | 1.133 cP📊 OPERA |
| Surface Tension | 26.752 dyn/cm📊 OPERA |
| Thermal Conductivity | 138.525 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 | 6 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 45.52 cm^3/mol📊 OPERA |
| Polarizability | 18.045 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.
