Isoamyl isovalerate (CAS 659-70-1) — Sweet Top Note Fragrance Ingredient
Isoamyl isovalerate
CAS 659-70-1
What Is Isoamyl isovalerate?
Isoamyl isovalerate is a synthetic ester often used in fruity and tropical fragrances. You’ll encounter it in citrusy body sprays, tropical vacation-inspired perfumes, and some fruit-flavored candies. This ingredient matters because it adds a juicy, apple-like sweetness that perfumers use to create mouthwatering top notes. It’s particularly valued for its ability to enhance berry and tropical fruit accords without smelling overly artificial.
Safety Profile
GENERALLY SAFEWhat Does Isoamyl isovalerate Smell Like?
Isoamyl isovalerate bursts with a bright, fruity character reminiscent of overripe apples dipped in tropical punch. The initial impression is intensely sweet – like a basket of mixed berries left in the sun, with a subtle fermented quality that adds depth. As it evolves, the scent softens into a candied apple core with whispers of banana peel and pineapple rind. The dry-down reveals a surprisingly clean muskiness, like fruit-scented soap lingering on warm skin. This ester maintains remarkable tenacity for a top note, often persisting for hours when blended with fixatives.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the citrus top notes with a juicy apple twist, creating an invigorating yet subtly sweet masculine opening that transitions smoothly into lavender heart notes.
Forms the fruity backbone of this limited edition summer scent, blending with passionfruit and mango to create a cocktail-like tropical fruit explosion.
2D Molecular Structure
SMILES: CC(C)CCOC(=O)CC(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Isoamyl isovalerate belongs to the ester class, formed through Fischer esterification between isovaleric acid and isoamyl alcohol. This branched-chain ester demonstrates how minor structural changes dramatically affect scent profiles – its isomer n-amyl isovalerate smells distinctly different. Industrial synthesis typically employs acid catalysis with sulfuric acid or ion-exchange resins. The molecule’s compact structure (C10H20O2) gives it relatively high volatility, while the ester linkage provides stability against hydrolysis compared to more reactive fragrance aldehydes.
Physical & Chemical Properties
| Boiling Point | 190-192 °C |
|---|---|
| Density | 0.858 g/cm³ |
| Refractive Index | 1.411 |
| Flash Point | 72 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Fruity top note enhancer |
| Body Sprays | 1-3% | Up to 8% | Main fruity component |
| Candles | 0.1-0.5% | Up to 1% | Fruit accord modifier |
| Flavorings | 10-50 ppm | Up to 100 ppm | Apple/berry flavor |
Classic Accords
Tip: Blend with bergamot and hedione to prevent the fruitiness from becoming cloying in the dry-down.
Alternatives & Comparisons
Offers a more straightforward banana-like fruitiness when a less complex fruity note is desired, though lacks the depth of isovalerate’s fermented character.
Provides similar fruity effects with a brighter, more sparkling quality, better suited for citrus-heavy compositions.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions currently apply (as of 51st Amendment).
RIFM Assessment
RIFM evaluation confirms safe use at current industry levels with no sensitization concerns.
Sustainability
As a purely synthetic material, isoamyl isovalerate doesn’t deplete natural resources. Production typically uses petrochemical feedstocks, though some manufacturers are exploring bio-based routes using fermented alcohols. The ester’s high potency means small quantities deliver significant olfactory impact, reducing overall environmental load compared to less powerful ingredients.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781439856333
- Arctander, S. (1969). Perfume and Flavor Chemicals. Allured Publishing. Industry Reference
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPerfumer’s Notes
FEMA #: 2085 | IOFI #: Nature Identical
Isoamyl isovalerate has a fruity, sweet, apple, apricot, mango-characteristic fruity odor and sweet-apple-like flavor.
Odor: [‘apple’, ‘apricot’, ‘cognac’, ‘fruity’, ‘green’, ‘pineapple’, ‘tropical’]
MW: 172.26
LogP: 3.1
Ingredient Data Sheet
CAS 659-70-1Physical Properties
| Molecular Weight | 172.26 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.1🔬 PubChem |
| Boiling Point | 190 °C🔬 EPA CompTox |
| Vapor Pressure | 1.2751 mmHg @ 25°C📊 OPERA |
| Flash Point | 73 °C🔬 EPA CompTox |
| Involatility Index | 0.1047💻 Calculated |
| log Kp (skin permeability) | -1.55💻 Calculated |
| SMILES | CC(C)CCOC(=O)CC(C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Moderate💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | appleapricotfruitygreenpineappletropical• leffingwell |
| Functional Groups | esterether💻 RDKit |
| “Peculiar fruity odor reminiscent of ripe apples, or more like the overwhelmingly choking odor of apples stored in a warehouse, almost a "fermented" apple odor.”📖 Arctander | |
| Isoamyl isovalerate has a fruity, sweet, apple, apricot, mango-characteristic fruity odor and sweet-apple-like flavor.📖 Fenaroli | |
Flavor Notes (Arctander)
| “Fresh-fruity taste, reminiscent of apple rind. Also of raspberry. Finds extensive use in flavor compositions, primarily in imitation Apple, and in the related "wine" or "Champagne" type imitation flavors for soft candy, beverages, etc. Further as a modifier in imitation Apricot, Banana, Cherry, Hone”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.3033 ppm (n=5)📖 van Gemert |
Regulatory Status
| FEMA Number | FEMA 2085⚖️ 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: DTXSID8044757
Physical Properties
| Molecular Weight | 172.268 g/mol🔬 EPA CompTox |
| Density | 0.853 g/cm^3🔬 EPA CTX |
| Boiling Point | 191.033 °C🔬 EPA CTX |
| Melting Point | -69.774 °C📊 OPERA |
| Flash Point | 70.11 °C🔬 EPA CTX |
| Refractive Index | 1.42 Dimensionless📊 OPERA |
| Molar Volume | 197.838 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.62 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.615 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.615 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.59 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 1.045 mmHg🔬 EPA CTX |
| Viscosity | 1.208 cP📊 OPERA |
| Surface Tension | 25.275 dyn/cm📊 OPERA |
| Thermal Conductivity | 126.952 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 | 0 count💻 Computed |
| Molar Refractivity | 50.07 cm^3/mol📊 OPERA |
| Polarizability | 19.849 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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