Propyl butyrate (CAS 105-66-8) — Sweet Top Note Fragrance Ingredient
Propyl butyrate
CAS 105-66-8
What Is Propyl butyrate?
Propyl butyrate is a synthetic ester widely used in food flavorings and perfumery. It imparts a fruity, pineapple-like aroma. Consumers encounter it in candies, beverages, and fruity fragrances. Its importance lies in providing realistic tropical fruit notes at low cost, making it a staple in mass-market products where natural extracts would be prohibitively expensive.
Safety Profile
GENERALLY SAFEWhat Does Propyl butyrate Smell Like?
Propyl butyrate bursts with a bright, effervescent pineapple top note – like biting into a perfectly ripe fruit with juicy sweetness. The heart reveals smoother pear and banana nuances, while the dry-down shows faint rum-like undertones. Unlike heavier esters, it remains relatively fresh throughout evaporation, though some waxy facets emerge in the final stages.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here as the primary pineapple accord, blended with passionfruit and coconut notes to create a photorealistic tropical cocktail effect.
Provides the sharp, fresh pineapple top note that makes this limited edition summer scent immediately recognizable.
2D Molecular Structure
SMILES: CCCOC(=O)CCC
Chemistry, Properties & Perfumer Guide
The Chemistry
Propyl butyrate is a simple ester formed from propanol and butyric acid. Industrially produced via acid-catalyzed esterification, it’s part of the C4-C6 ester family known for fruity characteristics. The molecular structure (CH3CH2COOCH2CH2CH3) lacks chirality, making synthesis straightforward. Its volatility stems from the short carbon chain, while the ester group provides both water solubility and organic phase compatibility.
Physical & Chemical Properties
| Boiling Point | 142-143 °C |
|---|---|
| Density | 0.875 g/cm³ |
| Refractive Index | 1.399 |
| Flash Point | 32 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | For fruity top notes |
| Functional Fragrance | 3-8% | Up to 15% | In soaps and detergents |
| Food Flavoring | 0.01-0.1% | Up to 0.5% | In candies and beverages |
Classic Accords
Tip: Combine with green notes to prevent cloying sweetness in fruity compositions.
Alternatives & Comparisons
More intense fruity character with higher volatility; better for fleeting top notes but less stable in formulations.
Longer-lasting with heavier fruit character; useful when more tenacity is needed in the heart phase.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions. Listed as Generally Recognized As Safe (GRAS) by FEMA.
RIFM Assessment
RIFM assessment confirms safety at current usage levels in fragrances.
Sustainability
Synthesized from petrochemical feedstocks, though production is energy-efficient. No known ecological toxicity at usage levels. Biodegradation occurs via esterase enzymes in wastewater treatment systems.
Explore Propyl butyrate
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References
- National Center for Biotechnology Information. PubChem Compound Summary for CID 7749, Propyl butyrate. PubChem
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 105-66-8Physical Properties
| Molecular Weight | 130.18 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.8🔬 PubChem |
| Boiling Point | 142 °C🔬 EPA CompTox |
| Vapor Pressure | 5.95 mmHg @ 25°C📊 OPERA |
| Flash Point | 38.9 °C🔬 EPA CompTox |
| Involatility Index | 0.562💻 Calculated |
| log Kp (skin permeability) | -2.216💻 Calculated |
| SMILES | CCCC(=O)OCCC🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Moderate💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | fruitysweet• leffingwell |
| Functional Groups | esterether💻 RDKit |
| “Heavy-fruity, Pineapple-like ethereal-pungent odor of poor tenacity.”📖 Arctander | |
| Propyl butyrate has a pineapple and apricot-like odor with a sweet, fruity flavor of banana and pineapple. The odor is also described as sharp, pungent, rancid, sweaty and sickening.📖 Fenaroli | |
Flavor Notes (Arctander)
| “Sweet-fruity, Banana-Pineapple-like taste in concentrations below 40 ppm. It is used in flavor compositions, in many fruit types, such as Banana, Pineapple, Plum, Strawberry, in Rum imitations, "Tutti-frutti" flavors, Liqueur flavors, etc.”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.0277 ppm (n=8)📖 van Gemert |
Regulatory Status
| FEMA Number | FEMA 2934⚖️ FEMA GRAS |
| GRAS Status | Generally Recognized as Safe⚖️ FEMA GRAS |
| IOFI Classification | Nature Identical📖 Fenaroli |
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: DTXSID6059318
Physical Properties
| Molecular Weight | 130.187 g/mol🔬 EPA CompTox |
| Density | 0.866 g/cm^3🔬 EPA CTX |
| Boiling Point | 142.75 °C🔬 EPA CTX |
| Melting Point | -65.1 °C🔬 EPA CTX |
| Flash Point | 36.738 °C🔬 EPA CTX |
| Refractive Index | 1.406 Dimensionless📊 OPERA |
| Molar Volume | 147.565 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.15 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 2.135 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.135 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.09 Log10 unitless📊 OPERA |
| Water Solubility | 0.012 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.001 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 5.638 mmHg🔬 EPA CTX |
| Viscosity | 0.791 cP📊 OPERA |
| Surface Tension | 25.7 dyn/cm📊 OPERA |
| Thermal Conductivity | 137.161 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 | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 36.254 cm^3/mol📊 OPERA |
| Polarizability | 14.372 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.
