Amyl isobutyrate (CAS 2445-72-9) — Sweet Top Note Fragrance Ingredient
Amyl isobutyrate
CAS 2445-72-9
What Is Amyl isobutyrate?
Amyl isobutyrate is a synthetic ester commonly used in fruit-flavored products and perfumes. It imparts a sweet, banana-like aroma. Found in chewing gums, candies, and some floral fragrances. This ingredient matters because it provides a cost-effective way to replicate tropical fruit notes without using natural extracts, which can vary in quality and availability.
Safety Profile
GENERALLY SAFEWhat Does Amyl isobutyrate Smell Like?
Amyl isobutyrate bursts with a juicy, ripe banana top note that quickly sweetens into a candied pear heart. The dry-down reveals a faint rum-like warmth, like the lingering trace of tropical cocktail on a sun-warmed glass. Though synthetic, it captures the essence of a fruit basket at peak ripeness.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as the primary synthetic banana note, creating an exaggerated candy sweetness that defines this playful, nostalgic fragrance.
Provides the artificial fruit cocktail accent that makes this body spray instantly recognizable to millennials.
2D Molecular Structure
SMILES: CCCCCOC(=O)C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Amyl isobutyrate is an ester formed from isoamyl alcohol and isobutyric acid. Industrially produced via acid-catalyzed esterification. The branched chain structure gives it greater stability than straight-chain esters while maintaining good volatility. Chiral centers mean commercial products are racemic mixtures unless specified otherwise.
Physical & Chemical Properties
| Boiling Point | 168-170 °C |
|---|---|
| Density | 0.868 g/cm³ |
| Flash Point | 57 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Food Flavoring | 5-50 ppm | Up to 100 ppm | Artificial fruit profiles |
| Body Care | 0.1-1% | Up to 3% | Sweetening agent |
| Fine Fragrance | 0.5-2% | Up to 5% | Tropical accents |
Classic Accords
Tip: Use with citrus top notes to prevent cloying sweetness.
Alternatives & Comparisons
More banana-forward, less sweet. Preferred for naturalistic fruit profiles rather than candy-like effects.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under IFRA 49th Amendment.
RIFM Assessment
RIFM-reviewed with no significant safety concerns at current usage levels.
Sustainability
Petroleum-derived but used in such small quantities that environmental impact is minimal. No known ecological toxicity at fragrance concentrations. Synthetic production avoids agricultural land use associated with natural fruit extracts.
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References
- Fenaroli’s Handbook of Flavor Ingredients (6th ed). CRC Press.
- PubChem Compound Summary for Amyl isobutyrate CID 24800
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 2445-72-9Physical Properties
| Molecular Weight | 158.24 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3🔬 PubChem |
| Boiling Point | 179 °C🔬 EPA CompTox |
| Vapor Pressure | 1.122 mmHg @ 25°C📊 OPERA |
| Flash Point | 59.4 °C🔬 EPA CompTox |
| Involatility Index | 0.0961💻 Calculated |
| log Kp (skin permeability) | -1.535💻 Calculated |
| SMILES | CCCCCOC(=O)C(C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | appleapricotfruitypineapple• leffingwell |
| Functional Groups | esterether💻 RDKit |
Sensory Thresholds
| Odor Detection Threshold | 0.0605 ppm (n=2)📖 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: DTXSID5074341
Physical Properties
| Molecular Weight | 158.241 g/mol🔬 EPA CompTox |
| Density | 0.875 g/cm^3📊 OPERA |
| Boiling Point | 178.185 °C📊 OPERA |
| Melting Point | -65.983 °C📊 OPERA |
| Flash Point | 59.827 °C📊 OPERA |
| Refractive Index | 1.417 Dimensionless📊 OPERA |
| Molar Volume | 180.955 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.172 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.172 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.172 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.43 Log10 unitless📊 OPERA |
| Water Solubility | 0.004 mol/L📊 OPERA |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 1.082 mmHg📊 OPERA |
| Viscosity | 1.115 cP📊 OPERA |
| Surface Tension | 25.721 dyn/cm📊 OPERA |
| Thermal Conductivity | 132.947 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 | 5 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 45.478 cm^3/mol📊 OPERA |
| Polarizability | 18.029 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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