Phenethyl isobutyrate (CAS 103-48-0) — Sweet Top to Middle Note Fragrance Ingredient
Phenethyl isobutyrate
CAS 103-48-0
What Is Phenethyl isobutyrate?
Phenethyl isobutyrate is a synthetic ester widely used in perfumery for its sweet, fruity, and floral aroma. It’s commonly found in personal care products like shampoos, soaps, and fine fragrances. This ingredient matters because it adds a fresh, rosy character to compositions while being cost-effective and stable in formulations.
Safety Profile
GENERALLY SAFEWhat Does Phenethyl isobutyrate Smell Like?
Phenethyl isobutyrate greets the nose with a burst of ripe pear and juicy strawberry, akin to candyfloss at a summer fair. As it settles, the scent evolves into a soft, rosy heart reminiscent of dew-kissed petals. The dry-down reveals a whisper of honeyed vanilla, leaving a clean, slightly powdery trail that lingers like the memory of a childhood dessert.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to enhance the floral bouquet with its sweet, fruity facets, adding modernity to the classic aldehydic structure.
Provides a candied rose effect that balances the chypre’s oakmoss bitterness with playful sweetness.
2D Molecular Structure
SMILES: CC(C)C(=O)OCCC1=CC=CC=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
Phenethyl isobutyrate is an ester formed from phenethyl alcohol and isobutyric acid. It belongs to the class of aromatic esters, prized for their stability and volatility profile. Industrially produced via acid-catalyzed esterification, this compound exhibits excellent shelf life and compatibility with other fragrance materials. Its simple structure lacks chirality, making synthesis straightforward without stereochemical concerns.
Physical & Chemical Properties
| Boiling Point | 230 °C |
|---|---|
| Density | 0.987 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | Adds fruity-floral lift |
| Soaps | 0.5-2% | Up to 3% | Stable in alkaline conditions |
Classic Accords
Tip: Use with citrus oils to prevent cloying sweetness in fruity florals.
Alternatives & Comparisons
More green-floral with less sweetness, preferred for lighter compositions.
Deeper honeyed character, used for oriental accords requiring more tenacity.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under IFRA 49th Amendment. Classified as non-sensitizing.
EU Allergen Declaration
Not listed in EU allergen regulation (EC) No 1223/2009.
RIFM Assessment
RIFM assessment confirms safe use at current industry levels.
Sustainability
Synthesized from petrochemical precursors, but requires minimal energy input compared to natural isolates. Biodegradability studies show >90% degradation in 28 days (OECD 301F).
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References
- PubChem Compound Summary for Phenethyl isobutyrate CID 7708
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 103-48-0Physical Properties
| Molecular Weight | 192.25 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.3🔬 PubChem |
| Boiling Point | 230 °C🔬 EPA CompTox |
| Vapor Pressure | 0.3375 mmHg @ 25°C📊 OPERA |
| Flash Point | 114 °C🔬 EPA CompTox |
| Involatility Index | 0.0262💻 Calculated |
| log Kp (skin permeability) | -1.53💻 Calculated |
| SMILES | CC(C)C(=O)OCCC1=CC=CC=C1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.9 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | floralfruityhoneyrose• leffingwell |
| Functional Groups | esteretheraromatic💻 RDKit |
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: DTXSID7044764
Physical Properties
| Molecular Weight | 192.258 g/mol🔬 EPA CompTox |
| Density | 0.988 g/cm^3🔬 EPA CTX |
| Boiling Point | 244.2 °C🔬 EPA CTX |
| Melting Point | 9.014 °C📊 OPERA |
| Flash Point | 108.567 °C🔬 EPA CTX |
| Refractive Index | 1.495 Dimensionless📊 OPERA |
| Molar Volume | 192.137 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.353 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.353 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.353 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.83 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.159 mmHg🔬 EPA CTX |
| Viscosity | 4.998 cP📊 OPERA |
| Surface Tension | 33.669 dyn/cm📊 OPERA |
| Thermal Conductivity | 135.038 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 | 1 count💻 Computed |
| Molar Refractivity | 56.067 cm^3/mol📊 OPERA |
| Polarizability | 22.227 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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