Benzyl isobutyrate (CAS 103-28-6) — Floral Heart Note Fragrance Ingredient
Benzyl isobutyrate
CAS 103-28-6
What Is Benzyl isobutyrate?
Benzyl isobutyrate is a synthetic floral fragrance compound commonly found in perfumes, soaps, and cosmetic products. It contributes a sweet, fruity-floral character reminiscent of ripe berries and garden flowers. This ester is prized for its ability to enhance floral bouquets while adding a juicy, slightly tropical nuance that makes fragrances feel more vibrant and approachable.
Safety Profile
GENERALLY SAFEWhat Does Benzyl isobutyrate Smell Like?
Benzyl isobutyrate opens with a burst of candied strawberries and pear drops, quickly settling into a heart of jammy rose petals drizzled with honey. The drydown reveals a clean, slightly powdery floralcy akin to freshly laundered linen infused with wildflower nectar. Unlike sharper benzyl acetate, it carries a rounded sweetness that blends seamlessly into oriental and fruity-floral compositions without dominating.
Scent Profile
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the grapefruit-jasmine accord, adding a dewy fruitiness that prevents the white flowers from becoming too heavy.
Provides the candied iris effect that makes this gourmand-floral hybrid so addictive, blending with ethyl maltol for a cotton candy illusion.
2D Molecular Structure
SMILES: CC(C)C(=O)OCC1=CC=CC=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
Benzyl isobutyrate belongs to the ester class, synthesized via Fischer esterification between benzyl alcohol and isobutyric acid. The branched isobutyl group confers greater stability against hydrolysis compared to linear chain esters. While not found in nature, its structural analogs occur in some tropical fruits. The compound’s volatility profile makes it ideal for heart note formulations where moderate persistence is desired.
Physical & Chemical Properties
| Appearance | Colorless liquid |
|---|---|
| Boiling Point | 229-230 °C |
| Density | 1.001 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | Up to 5% | Floral modifier |
| Soap | 0.5-1% | Up to 2% | Stable in alkaline systems |
Classic Accords
Tip: Use with ionones to create luminous fruity-floral effects that don’t turn syrupy.
Alternatives & Comparisons
For sharper jasmine effects with less sweetness. More volatile but requires careful dosing due to potential harshness.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. IFRA, REACH, EU Cosmetics Regulation standards update periodically. Consult current IFRA Standards Library before formulating. Not legal or regulatory advice.
IFRA Status
No restrictions under IFRA 51st Amendment.
RIFM Assessment
Evaluated as safe for current use levels in cosmetic applications (RIFM, 2015).
Sustainability
As a purely synthetic material, production avoids agricultural land use. Modern catalytic processes minimize waste in esterification. Biodegradability studies show >90% breakdown within 28 days under OECD test conditions.
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References
- Arctander, S. (1969). Perfume and Flavor Chemicals. Allured Publishing.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Mar 2026.
Report a data errorIngredient Data Sheet
CAS 103-28-6Physical Properties
| Molecular Weight | 178.23 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3🔬 PubChem |
| Boiling Point | 229 °C🔬 EPA CompTox |
| Flash Point | 92.3 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.657💻 Calculated |
| SMILES | CC(C)C(=O)OCC1=CC=CC=C1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
Odor & Flavor
| Primary Descriptors | floralfruity• leffingwell |
| Functional Groups | esteretheraromatic💻 RDKit |
| Benzyl isobutyrate has a fresh, floral, somewhat jasmine-like, fruity odor and sweet, strawberry-like taste.📖 Fenaroli | |
Regulatory Status
| 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: DTXSID6047602
Physical Properties
| Molecular Weight | 178.231 g/mol🔬 EPA CompTox |
| Density | 1.019 g/cm^3🔬 EPA CTX |
| Boiling Point | 230.125 °C🔬 EPA CTX |
| Melting Point | -60 °C🔬 EPA CTX |
| Flash Point | 95.863 °C🔬 EPA CTX |
| Refractive Index | 1.497 Dimensionless📊 OPERA |
| Molar Volume | 175.63 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.99 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 2.971 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.971 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.87 Log10 unitless📊 OPERA |
| Water Solubility | 0.006 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.034 mmHg📊 OPERA |
| Viscosity | 3.329 cP📊 OPERA |
| Surface Tension | 33.714 dyn/cm📊 OPERA |
| Thermal Conductivity | 134.232 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 | 1 count💻 Computed |
| Molar Refractivity | 51.434 cm^3/mol📊 OPERA |
| Polarizability | 20.39 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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