Butyl isobutyrate (CAS 97-87-0) — Sweet Top Note Fragrance Ingredient
Butyl isobutyrate
CAS 97-87-0
What Is Butyl isobutyrate?
Butyl isobutyrate is a fruity-smelling synthetic compound commonly used in food flavorings and perfumes. You’ll encounter it in artificial fruit flavors like apple and pineapple, as well as in fresh, uplifting fragrances. This ester matters because it adds a crisp, natural-seeming fruitiness to products without the instability of actual fruit extracts. Its clean, bright character helps create the illusion of just-picked freshness in everything from body sprays to hard candies.
Safety Profile
GENERALLY SAFEWhat Does Butyl isobutyrate Smell Like?
Butyl isobutyrate bursts with a juicy, top-note intensity reminiscent of ripe green apples and freshly cut pineapple. The initial impression is all effervescent fruitiness—think sparkling cider with a candied edge. As it settles, a softer, almost pear-like sweetness emerges, rounded out by a whisper of fresh-cut stalks. The dry-down reveals a clean, slightly waxy undertone that prevents cloying sweetness, making it exceptionally versatile in both gourmand and fresh compositions. Its behavior is linear yet dynamic, maintaining fruity clarity without evolving dramatically—perfect for maintaining consistent fruit accords.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the citrus-fruit opening, adding juicy realism to the bergamot and apple notes while enhancing the fragrance’s overall freshness.
Provides a crisp, fruity lift to the classic citrus cologne structure, blending seamlessly with lemon and herbal notes for a modern twist.
2D Molecular Structure
SMILES: CCCCOC(=O)C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Butyl isobutyrate belongs to the ester class, synthesized via Fischer esterification between isobutyric acid and n-butanol. This straightforward reaction produces a molecule with excellent stability and purity. While not found abundantly in nature, traces occur in some fruits and fermented products. The ester’s compact structure gives it high volatility, making it a quintessential top note. Its chirality isn’t commercially significant since most synthetic routes produce racemic mixtures. The compound’s fruity character stems from its molecular shape, which fits olfactory receptors typically activated by ripe fruits.
Physical & Chemical Properties
| Boiling Point | 148-150 °C |
|---|---|
| Density | 0.86 g/cm³ |
| Refractive Index | 1.399-1.401 |
| Flash Point | 40 °C |
| Solubility | Slightly soluble in water, miscible with alcohols |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-3% | Up to 5% | Fruit accord booster |
| Functional Products | 0.1-1% | Up to 2% | Freshness enhancer |
Classic Accords
Tip: Use with citrus oils to prevent harshness—it rounds out sharp edges while maintaining brightness.
Alternatives & Comparisons
More banana-like character; use when needing warmer fruit tones or when butyl isobutyrate’s apple quality is too sharp.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions—unlimited use permitted under current standards.
RIFM Assessment
RIFM evaluation confirms safe use at current industry levels with wide margins of safety.
Sustainability
Synthesized from petrochemical feedstocks, but its high potency means minimal quantities are needed. Production is energy-efficient compared to natural fruit extracts. Not known to bioaccumulate and readily biodegradable under standard OECD tests.
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References
- Fenaroli’s Handbook of Flavor Ingredients (6th Ed.) ISBN 9781439862513
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 97-87-0Physical Properties
| Molecular Weight | 144.21 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.4🔬 PubChem |
| Boiling Point | 156 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.876💻 Calculated |
| SMILES | CCCCOC(=O)C(C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
Odor & Flavor
| Primary Descriptors | fruity• leffingwell |
| Functional Groups | esterether💻 RDKit |
| “Fresh-fruity, rather penetrating odor, reminiscent of Apple, Banana and Pineapple. Not as ethereal as the iso-Butyl-n-butyrate.”📖 Arctander | |
| Butyl isobutyrate has a strong, fresh, fruity odor (apple, banana) and sweet, pineapple-like taste.📖 Fenaroli | |
Flavor Notes (Arctander)
| “Sweet fruity Banana-Pineapple like taste in aqueous media. Used in flavor compositions for imitation Apple, Apricot, Banana, Arak, Butter, Cherry, Ginger, Gooseberry, Hop, Melon, Blackberry, Orange, Peach, Pineapple, Raspberry, Strawberry, Tangerine, etc. Concentrations in the finished product are n”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.2107 ppm (n=6)📖 van Gemert |
Regulatory Status
| FEMA Number | FEMA 2188⚖️ 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: DTXSID9073888
Physical Properties
| Molecular Weight | 144.214 g/mol🔬 EPA CompTox |
| Density | 0.879 g/cm^3📊 OPERA |
| Boiling Point | 156 °C🔬 EPA CTX |
| Melting Point | -72.447 °C📊 OPERA |
| Flash Point | 46.942 °C📊 OPERA |
| Refractive Index | 1.411 Dimensionless📊 OPERA |
| Molar Volume | 164.448 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.485 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.485 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.485 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.94 Log10 unitless📊 OPERA |
| Water Solubility | 0.01 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 2.91 mmHg📊 OPERA |
| Viscosity | 0.92 cP📊 OPERA |
| Surface Tension | 25.184 dyn/cm📊 OPERA |
| Thermal Conductivity | 131.661 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 | 40.845 cm^3/mol📊 OPERA |
| Polarizability | 16.192 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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