Ethyl isobutyrate (CAS 97-62-1) — Sweet Top Note Fragrance Ingredient
Ethyl isobutyrate
CAS 97-62-1
What Is Ethyl isobutyrate?
Ethyl isobutyrate is a fruity ester commonly found in artificial flavorings and perfumes. You’ll recognize its sweet, rum-like scent in candies, sodas, and tropical fruit fragrances. This versatile ingredient matters because it adds an instant juicy freshness to compositions, acting as a bridge between citrus top notes and deeper fruity heart accords. Its affordability and stability make it a workhorse in mass-market products.
Safety Profile
GENERALLY SAFEWhat Does Ethyl isobutyrate Smell Like?
A burst of overripe pineapple and banana Runts candy that quickly settles into a boozy, fermented fruit character. The opening is intensely sweet with a metallic sharpness reminiscent of canned fruit syrup, evolving into a warm rum-like base with hints of caramelized sugar. Dry-down reveals a slightly waxy, artificial fruit note that persists close to skin. Surprisingly tenacious for such a light molecule, it behaves like a fruitier cousin of ethyl acetate with better longevity.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used in the explosive fruity-candy opening, contributing to the signature blood orange and cinnamon bubblegum effect that made this fragrance iconic.
Boosts the lychee-raspberry accord with its hyper-realistic candy fruit character, creating the fragrance’s addictive ‘pink berry’ signature.
Works behind the citrus notes to amplify the tropical fruit impressions, giving the lemon a juicy, cocktail-like quality.
2D Molecular Structure
SMILES: CCOC(=O)C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Ethyl isobutyrate is an ester formed from ethanol and isobutyric acid, typically synthesized via acid-catalyzed esterification. As a small, volatile ester (C6H12O2), it’s part of the fruity ester family alongside ethyl acetate and isoamyl acetate. Industrial production often uses sulfuric acid as a catalyst at reflux temperatures. The molecule’s compact structure gives it high volatility and low molecular weight (116.16 g/mol), explaining its potent odor impact at low concentrations. Chiral variants exist but are rarely separated in commercial production.
Physical & Chemical Properties
| Boiling Point | 110-112 °C |
|---|---|
| Density | 0.867 g/cm³ |
| Flash Point | 12 °C (closed cup) |
| Vapor Pressure | 25.5 mmHg at 25°C |
| Solubility | Slightly soluble in water, miscible with ethanol |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used sparingly for fruity top notes |
| Functional Fragrances | 1-3% | Up to 10% | Boosts fruity detergents and cleaners |
| Flavorings | 10-50 ppm | Up to 100 ppm | Artificial fruit flavors |
Classic Accords
Tip: Use at 0.1-0.5% in alcohol bases to prevent excessive volatility and candy-like overdosing.
Alternatives & Comparisons
More expensive but with a richer, juicier apple character and less artificial candy note, preferred in premium formulations.
For banana-focused accords, though less versatile and more solvent-like in character.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under current IFRA Standards (49th Amendment).
GHS Classification
RIFM Assessment
RIFM evaluation confirms safe use at current industry levels with no sensitization concerns.
Sustainability
Synthesized from petrochemical feedstocks via energy-intensive processes, though its high odor impact means minimal quantities are needed. No known ecological toxicity at usage levels, but flammability requires careful handling. Some producers are exploring bio-based routes using fermented isobutyric acid.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090867
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 97-62-1Physical Properties
| Molecular Weight | 116.16 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.5🔬 PubChem |
| Boiling Point | 112 °C🔬 EPA CompTox |
| Vapor Pressure | 25.4 mmHg @ 25°C📊 OPERA |
| Flash Point | 21.1 °C🔬 EPA CompTox |
| Involatility Index | 2.54💻 Calculated |
| log Kp (skin permeability) | -2.344💻 Calculated |
| SMILES | CCOC(=O)C(C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Fast💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | appleetherealfruityrumsweet• leffingwell |
| Functional Groups | esterether💻 RDKit |
| “It is advisable, however, to keep both esters absolutely dry in storage. The presence of even minute amounts of free acid is detrimental to the odor of the esters. For flavor use, it is not a serious drawback, since traces of free Butyric acids may even be desirable in fruity compositions.”📖 Arctander | |
| Ethyl isobutyrate has a fruity aromatic odor.📖 Fenaroli | |
Flavor Notes (Arctander)
| “It is advisable, however, to keep both esters absolutely dry in storage. The presence of even minute amounts of free acid is detrimental to the odor of the esters. For flavor use, it is not a serious drawback, since traces of free Butyric acids may even be desirable in fruity compositions.”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.0813 ppm (n=16)📖 van Gemert |
Regulatory Status
| FEMA Number | FEMA 2428⚖️ 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: DTXSID7047728
Physical Properties
| Molecular Weight | 116.16 g/mol🔬 EPA CompTox |
| Density | 0.866 g/cm^3🔬 EPA CTX |
| Boiling Point | 111.32 °C🔬 EPA CTX |
| Melting Point | -88.109 °C🔬 EPA CTX |
| Flash Point | 13.363 °C🔬 EPA CTX |
| Refractive Index | 1.396 Dimensionless📊 OPERA |
| Molar Volume | 131.435 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.8 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 1.739 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.739 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.24 Log10 unitless📊 OPERA |
| Water Solubility | 0.056 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.001 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 25.862 mmHg🔬 EPA CTX |
| Viscosity | 0.602 cP📊 OPERA |
| Surface Tension | 24.079 dyn/cm📊 OPERA |
| Thermal Conductivity | 131.251 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 | 2 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 31.58 cm^3/mol📊 OPERA |
| Polarizability | 12.519 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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