Isobutyl hexanoate (CAS 105-79-3) — Sweet Top Note Fragrance Ingredient
Isobutyl hexanoate
CAS 105-79-3
What Is Isobutyl hexanoate?
Isobutyl hexanoate is a synthetic fragrance ingredient commonly found in fruity perfumes, body care products, and food flavorings. It delivers a sweet, apple-like scent with tropical nuances that makes it popular in summer fragrances. This ester matters because it adds realistic fruitiness without being cloying, bridging the gap between citrus top notes and floral heart notes in many compositions.
Safety Profile
GENERALLY SAFEWhat Does Isobutyl hexanoate Smell Like?
Isobutyl hexanoate bursts with juicy, freshly cut apple peel character – think Red Delicious at peak ripeness. The top note has a sparkling effervescence reminiscent of apple cider, softening into a candied pineapple heart with subtle banana custard undertones. As it dries down, it reveals a clean, slightly waxy texture like fruit salad syrup, leaving a faint vanilla-tinged sweetness on skin. The projection is moderate but persistent, making it excellent for fruity-floral blends.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Provides the crisp apple backbone that contrasts with the citrus opening and floral heart, creating its signature Mediterranean freshness.
Used sparingly to enhance the pear and melon facets, adding juicy realism to the white floral bouquet.
2D Molecular Structure
SMILES: CCCCCC(=O)OCC(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Isobutyl hexanoate belongs to the ester family, formed via Fischer esterification of isobutanol and hexanoic acid. This branched-chain ester exhibits excellent stability in both acidic and alkaline formulations. Its volatility profile makes it ideal for top notes, with the isobutyl group contributing to its distinctive fruity character. The hexanoate chain length provides optimal balance between hydrophobicity and odor intensity.
Physical & Chemical Properties
| Boiling Point | 172-174 °C |
|---|---|
| Density | 0.858 g/cm³ |
| Refractive Index | 1.412 |
| Flash Point | 62 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-3% | Up to 5% | Fruity top note enhancer |
| Body Care | 0.1-1% | Up to 2% | Shower gel fruity effects |
Classic Accords
Tip: Combine with allyl amyl glycolate for enhanced pear effects or with cis-3-hexenol for greener fruit nuances.
Alternatives & Comparisons
More floral-pear like with higher volatility, better for fleeting top notes in citrus colognes.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under IFRA 51st Amendment.
RIFM Assessment
RIFM evaluation confirms safe use at current industry levels.
Sustainability
Synthesized from petrochemical feedstocks with high atom economy (85%+). Biodegradation studies show 90% breakdown in 28 days. No known ecological toxicity concerns at usage levels. Preferred over natural apple isolates for consistent quality and yield.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090869
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 105-79-3Physical Properties
| Molecular Weight | 172.26 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.4🔬 PubChem |
| Boiling Point | 199 °C🔬 EPA CompTox |
| Vapor Pressure | 0.6918 mmHg @ 25°C📊 OPERA |
| Flash Point | 76.1 °C🔬 EPA CompTox |
| Involatility Index | 0.0568💻 Calculated |
| log Kp (skin permeability) | -1.337💻 Calculated |
| SMILES | CCCCCC(=O)OCC(C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | fruitypineapple• leffingwell |
| Functional Groups | esterether💻 RDKit |
| “Heavy winey-fruit Pineapple-like odor. Fresher than the n-Butylester, and it displays, according to some observers, a Cocoa-like undertone.”📖 Arctander | |
| Apple, fruity odor with cocoa-like undertone.📖 Fenaroli | |
Flavor Notes (Arctander)
| “It is used extensively in flavor compositions, primarily in imitation Pineapple, but also in Apple, Grape and other fruity types.”📖 Arctander |
Regulatory Status
| FEMA Number | FEMA 2202⚖️ 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: DTXSID0059322
Physical Properties
| Molecular Weight | 172.268 g/mol🔬 EPA CompTox |
| Density | 0.856 g/cm^3🔬 EPA CTX |
| Boiling Point | 197.497 °C📊 OPERA |
| Melting Point | -63.842 °C📊 OPERA |
| Flash Point | 74.194 °C📊 OPERA |
| Refractive Index | 1.421 Dimensionless📊 OPERA |
| Molar Volume | 197.462 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.706 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.706 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.706 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.97 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.512 mmHg📊 OPERA |
| Viscosity | 1.236 cP📊 OPERA |
| Surface Tension | 25.909 dyn/cm📊 OPERA |
| Thermal Conductivity | 134.23 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 | 50.111 cm^3/mol📊 OPERA |
| Polarizability | 19.866 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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