Isobutyl isobutyrate (CAS 97-85-8) — Sweet Top Note Fragrance Ingredient
Isobutyl isobutyrate
CAS 97-85-8
What Is Isobutyl isobutyrate?
Isobutyl isobutyrate is a synthetic ester commonly used in fruity and floral fragrances. You’ll encounter it in body sprays, shampoos, and air fresheners for its fresh, sweet aroma. This ingredient matters because it adds a crisp, apple-like top note that blends seamlessly with other fruity accords, creating uplifting scent experiences.
Safety Profile
GENERALLY SAFEWhat Does Isobutyl isobutyrate Smell Like?
Isobutyl isobutyrate bursts with a juicy, green apple top note that’s slightly tart yet sweet, like biting into a freshly picked Granny Smith. As it evolves, the scent softens into a candied pear heart with hints of pineapple core. The dry-down reveals a faintly woody, almost rum-like base that lingers close to skin. Its volatility creates a sparkling effect in compositions, making it perfect for refreshing citrus and tropical fruit accords.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to enhance the crisp apple note that defines this Mediterranean-inspired fragrance, blending with Sicilian lemon for a refreshing opening.
Provides subtle fruity facets that complement the ambergris base, adding dimension to the salty marine accord.
2D Molecular Structure
SMILES: CC(C)COC(=O)C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Isobutyl isobutyrate belongs to the ester class, formed by esterification of isobutyric acid with isobutanol. Industrially produced via acid-catalyzed Fischer esterification, it’s a colorless liquid with high volatility. The branched structure of both the alcohol and acid components contributes to its distinctive fruity character and lower boiling point compared to straight-chain esters.
Physical & Chemical Properties
| Boiling Point | 148-150 °C |
|---|---|
| Density | 0.87 g/cm³ |
| Refractive Index | 1.403 |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Fruity top note enhancer |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Freshness booster |
Classic Accords
Tip: Use in citrus colognes at 0.2-0.5% to add naturalistic fruity depth without overpowering.
Alternatives & Comparisons
For stronger banana notes when a more tropical fruit effect is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions apply (48th Amendment).
RIFM Assessment
Evaluated as safe for current fragrance use levels by RIFM (2015).
Sustainability
As a synthetic material, isobutyl isobutyrate has minimal environmental impact during production. Its efficient synthesis from petrochemical feedstocks results in high purity and consistent quality without natural resource depletion concerns.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090772
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 97-85-8Physical Properties
| Molecular Weight | 144.21 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.5🔬 PubChem |
| Boiling Point | 148.7 °C🔬 EPA CompTox |
| Vapor Pressure | 4.33 mmHg @ 25°C📊 OPERA |
| Flash Point | 37.2 °C🔬 EPA CompTox |
| Involatility Index | 0.3886💻 Calculated |
| log Kp (skin permeability) | -1.805💻 Calculated |
| SMILES | CC(C)COC(=O)C(C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Moderate💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | bananafruitypineapplesweettropical• leffingwell |
| Functional Groups | esterether💻 RDKit |
| “Sweet-fruity, but also rather harsh-Pine-apple-like, diffusive-ethereal odor. Fresher, but less characteristic (a non-descript fruit type) than the other isomers.”📖 Arctander | |
| Isobutyl isobutyrate has an odor and taste reminiscent of pineapple.📖 Fenaroli | |
Flavor Notes (Arctander)
| “Used in flavor compositions for imitation Arak, Banana, Brandy, Butter, Fruit (Tutti-frutti), Liquor, etc.”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 1.2475 ppm (n=8)📖 van Gemert |
Regulatory Status
| FEMA Number | FEMA 2189⚖️ 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: DTXSID6026612
Physical Properties
| Molecular Weight | 144.214 g/mol🔬 EPA CompTox |
| Density | 0.854 g/cm^3🔬 EPA CTX |
| Boiling Point | 148.463 °C🔬 EPA CTX |
| Melting Point | -80.742 °C🔬 EPA CTX |
| Flash Point | 37.266 °C🔬 EPA CTX |
| Refractive Index | 1.41 Dimensionless📊 OPERA |
| Molar Volume | 164.825 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.71 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 2.492 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.492 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.87 Log10 unitless📊 OPERA |
| Water Solubility | 0.01 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.001 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 3.967 mmHg🔬 EPA CTX |
| Viscosity | 0.829 cP📊 OPERA |
| Surface Tension | 24.719 dyn/cm📊 OPERA |
| Thermal Conductivity | 124.874 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 | 3 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 40.804 cm^3/mol📊 OPERA |
| Polarizability | 16.176 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.
