Phenethyl isovalerate (CAS 140-26-1) — Floral Middle Note Fragrance Ingredient
Phenethyl isovalerate
CAS 140-26-1
What Is Phenethyl isovalerate?
Phenethyl isovalerate is a synthetic fragrance compound often found in floral and fruity perfumes, body care products, and some food flavorings. It contributes a sweet, rosy, and slightly fruity aroma. This ingredient matters because it’s a versatile building block in perfumery, helping create complex floral bouquets and adding depth to fruity compositions without being overpowering.
Safety Profile
GENERALLY SAFEWhat Does Phenethyl isovalerate Smell Like?
Phenethyl isovalerate opens with an effervescent burst of ripe pear and banana peel, quickly settling into a lush rosy heart reminiscent of damask petals soaked in honey. The base reveals a creamy, almost lactonic undertone that binds beautifully to woody accords. Unlike simpler phenethyl esters, its isovalerate twist adds a subtle animalic edge that prevents the sweetness from becoming cloying, making it particularly useful in modern floral-oriental hybrids.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used sparingly to enhance the floral bouquet, adding a fruity-rosy dimension that bridges the aldehydic top to the vanilla base.
Contributes to the champagne-like effervescence in the top notes while supporting the magnolia heart accord.
Helps create the candied rose effect by blending patchouli’s earthiness with sweet floralcy.
Adds a gourmand twist to the iris-patchouli core, making the sweetness more dimensional.
2D Molecular Structure
SMILES: CC(C)CC(=O)OCCC1=CC=CC=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
Phenethyl isovalerate is an ester formed by the condensation of phenethyl alcohol and isovaleric acid. While theoretically obtainable through enzymatic esterification in nature, commercial production typically involves acid-catalyzed Fischer esterification. The branched isovaleryl group introduces steric hindrance that affects volatility and odor characteristics compared to linear chain esters. Modern synthesis often employs lipase-catalyzed reactions under mild conditions for higher purity and sustainability.
Physical & Chemical Properties
| Boiling Point | ~250 °C (estimated) |
|---|---|
| Density | ~0.98 g/cm³ (estimated) |
| Refractive Index | 1.486-1.490 |
| Flash Point | >100 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-3% | Up to 5% | Floral modifier |
| Soap | 0.1-1% | Up to 2% | Adds persistence |
| Candles | 0.5-2% | Up to 3% | Good heat stability |
Classic Accords
Tip: Use with ionones to create a seamless rose-violet transition in floral compositions.
Alternatives & Comparisons
For brighter, more diffusive rose notes with less fruity density.
When greater tenacity and honeyed character are desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted under current IFRA standards (Amendment 49).
RIFM Assessment
Evaluated by RIFM in 2003 with no significant safety concerns at reported use levels.
Sustainability
As a synthetic material, phenethyl isovalerate avoids agricultural land use but depends on petrochemical feedstocks. Modern production methods increasingly utilize green chemistry principles, including enzymatic catalysis and solvent-free reactions. Its high odor potency means minimal quantities are needed, reducing overall environmental load compared to some natural extracts.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781439832271
- IFRA Standards Library IFRA
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 140-26-1Physical Properties
| Molecular Weight | 206.28 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.6🔬 PubChem |
| Boiling Point | 263 °C🔬 EPA CompTox |
| Flash Point | 100 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.402💻 Calculated |
| SMILES | CC(C)CC(=O)OCCC1=CC=CC=C1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
Odor & Flavor
| Primary Descriptors | balsamicfruityrose• leffingwell |
| Functional Groups | esteretheraromatic💻 RDKit |
| Phenethyl isovalerate has a fruity (rose-peach-apricot) odor and a bittersweet flavor, reminiscent of peach. It is not very stable.📖 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: DTXSID2059693
Physical Properties
| Molecular Weight | 206.285 g/mol🔬 EPA CompTox |
| Density | 0.973 g/cm^3🔬 EPA CTX |
| Boiling Point | 263.5 °C🔬 EPA CTX |
| Melting Point | 13.345 °C📊 OPERA |
| Flash Point | 105.367 °C🔬 EPA CTX |
| Refractive Index | 1.494 Dimensionless📊 OPERA |
| Molar Volume | 208.643 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.685 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.685 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.685 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.72 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.016 mmHg📊 OPERA |
| Viscosity | 6.367 cP📊 OPERA |
| Surface Tension | 33.705 dyn/cm📊 OPERA |
| Thermal Conductivity | 135.629 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 | 5 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 60.7 cm^3/mol📊 OPERA |
| Polarizability | 24.063 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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