Isobutyl benzoate (CAS 120-50-3) — Sweet Top to middle Note Fragrance Ingredient
Isobutyl benzoate
CAS 120-50-3
What Is Isobutyl benzoate?
Isobutyl benzoate is a synthetic fragrance ingredient commonly found in perfumes, cosmetics, and household products. It contributes a sweet, floral, and slightly fruity aroma. This ester is valued for its ability to enhance floral compositions and add a subtle fruity nuance without overpowering other notes.
Safety Profile
GENERALLY SAFEWhat Does Isobutyl benzoate Smell Like?
Isobutyl benzoate presents a sweet, floral aroma with a subtle fruity undertone reminiscent of ripe peaches and fresh roses. Its top note is bright and slightly powdery, evolving into a heart that balances floral sweetness with a clean, slightly balsamic character. The dry-down is soft and lingering, leaving a delicate floral-fruity trail that blends seamlessly with other ingredients.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to enhance the floral bouquet, adding a soft fruity nuance that complements the aldehydic top notes and powdery dry-down.
Adds a subtle fruity-floral accent to the chypre structure, balancing the mossy base with a touch of sweetness.
Contributes to the lush floral heart, providing a smooth, sweet backdrop for the rose and jasmine notes.
Used to soften the spicy carnation note, adding a delicate fruity-floral harmony.
Enhances the vanilla and powdery notes with a subtle fruity-floral accent.
2D Molecular Structure
SMILES: CC(C)COC(=O)C1=CC=CC=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
Isobutyl benzoate is an ester formed by the condensation of benzoic acid and isobutanol. It is typically synthesized via esterification under acidic conditions. This compound belongs to the class of aromatic esters, known for their sweet and floral odor profiles. Its molecular structure features a benzene ring esterified with an isobutyl group, contributing to its volatility and solubility properties.
Physical & Chemical Properties
| Boiling Point | 198 °C |
|---|---|
| Density | 0.865 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | Adds floral-fruity nuances |
| Cosmetics | 0.5-3% | Up to 5% | Softens floral compositions |
| Household Products | 0.1-1% | Up to 2% | Provides subtle sweetness |
Classic Accords
Tip: Use in floral compositions to add a smooth, fruity-floral accent without overpowering the main notes.
Alternatives & Comparisons
Offers a sweeter, more balsamic character with better fixative properties.
Provides a stronger fruity note with a slightly heavier dry-down.
Delivers a sharper, more herbal-floral profile with higher volatility.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under IFRA standards.
RIFM Assessment
RIFM assessment confirms safety for current usage levels in fragrance applications.
Sustainability
Isobutyl benzoate is synthesized from petrochemical sources, making it a consistent and scalable ingredient. Its production has a relatively low environmental impact compared to some natural alternatives, as it avoids agricultural land use and seasonal variability.
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References
- PubChem. Isobutyl benzoate. PubChem
- Arctander, S. (1969). Perfume and Flavor Chemicals. Allured Publishing.
- Bauer, K. et al. (2001). Common Fragrance and Flavor Materials. Wiley-VCH.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 120-50-3Physical Properties
| Molecular Weight | 178.23 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.6🔬 PubChem |
| Boiling Point | 242 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.231💻 Calculated |
| SMILES | CC(C)COC(=O)C1=CC=CC=C1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
Odor & Flavor
| Primary Descriptors | balsamicfloralfruitygreenleafyrose• leffingwell |
| Functional Groups | esteretheraromatic💻 RDKit |
| “Weak, but fresh and pleasant, tenacious orrisy odor with green-rosy undertones, less balsamic than the n-Butylester.”📖 Arctander | |
| Isobutyl benzoate has a green, floral-leafy odor reminiscent of rose and geranium.📖 Fenaroli | |
Flavor Notes (Arctander)
| “Used in flavor compositions for imitation Berry, Fruit, Cherry, Pineapple, Plum, etc.”📖 Arctander |
Regulatory Status
| FEMA Number | FEMA 2185⚖️ 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: DTXSID6047074
Physical Properties
| Molecular Weight | 178.231 g/mol🔬 EPA CompTox |
| Density | 0.998 g/cm^3🔬 EPA CTX |
| Boiling Point | 241.667 °C🔬 EPA CTX |
| Melting Point | -0.739 °C📊 OPERA |
| Flash Point | 100.691 °C📊 OPERA |
| Refractive Index | 1.497 Dimensionless📊 OPERA |
| Molar Volume | 177.223 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.23 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.467 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.467 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.87 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.06 mmHg📊 OPERA |
| Viscosity | 4.299 cP📊 OPERA |
| Surface Tension | 34.035 dyn/cm📊 OPERA |
| Thermal Conductivity | 134.009 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 | 51.883 cm^3/mol📊 OPERA |
| Polarizability | 20.568 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.
