Butyl hexanoate (CAS 626-82-4) — Sweet Top Note Fragrance Ingredient
Butyl hexanoate
CAS 626-82-4
What Is Butyl hexanoate?
Butyl hexanoate is a synthetic ester commonly used in fruit-flavored products and fragrances. You’ll encounter it in tropical-scented body care items and some citrus-forward perfumes. This ingredient matters because it provides a realistic, juicy pineapple note that’s more stable than natural extracts, allowing fruity accords to last longer in products.
Safety Profile
GENERALLY SAFEWhat Does Butyl hexanoate Smell Like?
Butyl hexanoate bursts open with a vibrant pineapple top note – think freshly cut tropical fruit with a slight metallic edge. As it evolves, the sweetness mellows into a candied pear heart with undertones of overripe melon. The dry-down reveals a subtle waxy character reminiscent of fruit-flavored chewing gum, leaving a clean, slightly green finish. Its behavior is linear compared to natural fruit extracts, maintaining its character without dramatic shifts.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the coconut-pineapple cocktail accord, providing a photorealistic tropical fruit effect that blends seamlessly with the lime and rum notes.
Forms the core pineapple note in this Aventus-inspired fragrance, giving longevity to what would otherwise be a fleeting top note.
2D Molecular Structure
SMILES: CCCCCC(=O)OCCCC
Chemistry, Properties & Perfumer Guide
The Chemistry
Butyl hexanoate belongs to the ester class, formed through esterification of butanol with hexanoic acid. While found in trace amounts in some fruits, commercial production is entirely synthetic via acid-catalyzed Fischer esterification. The molecule lacks chiral centers, making stereochemistry irrelevant for its olfactory properties. Its relatively simple structure contributes to excellent stability in formulations.
Physical & Chemical Properties
| Boiling Point | 168 °C |
|---|---|
| Density | 0.865 g/cm³ |
| Refractive Index | 1.406 |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-3% | Up to 5% | Fruit accords |
| Body Care | 0.1-1% | Up to 2% | Tropical formulations |
Classic Accords
Tip: Combine with gamma-undecalactone for a more complex pineapple effect.
Alternatives & Comparisons
More diffusive with stronger pineapple character but less longevity. Better for top note emphasis.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions apply.
RIFM Assessment
RIFM has evaluated butyl hexanoate as safe for current use levels in fragrance applications.
Sustainability
As a synthetic material, butyl hexanoate has minimal environmental impact in production. Its efficient synthesis from petrochemical feedstocks makes it more sustainable than natural fruit extracts that require agricultural land and processing. The material’s stability reduces waste in formulations.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID8060824
Physical Properties
| Molecular Weight | 172.268 g/mol🔬 EPA CompTox |
| Density | 0.862 g/cm^3🔬 EPA CTX |
| Boiling Point | 208 °C🔬 EPA CTX |
| Melting Point | -65.12 °C🔬 EPA CTX |
| Flash Point | 81.175 °C🔬 EPA CTX |
| Refractive Index | 1.423 Dimensionless📊 OPERA |
| Molar Volume | 197.085 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.675 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.675 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.675 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.06 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.272 mmHg📊 OPERA |
| Viscosity | 1.312 cP📊 OPERA |
| Surface Tension | 27.106 dyn/cm📊 OPERA |
| Thermal Conductivity | 139.135 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 | 7 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 50.152 cm^3/mol📊 OPERA |
| Polarizability | 19.882 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.
