Butyl isovalerate (CAS 109-19-3) — Sweet Top Note Fragrance Ingredient
Butyl isovalerate
CAS 109-19-3
What Is Butyl isovalerate?
Butyl isovalerate is a synthetic ester commonly used in fruity and apple-like fragrances. You’ll encounter it in candies, chewing gums, and some fresh-smelling perfumes. This ingredient matters because it provides a crisp, juicy apple note that’s more stable than natural extracts, allowing fragrances to maintain their character longer.
Safety Profile
GENERALLY SAFEWhat Does Butyl isovalerate Smell Like?
Butyl isovalerate bursts with a vibrant, green apple peel intensity – think biting into a freshly picked Granny Smith. The top note carries a slightly fermented fruitiness reminiscent of cider, which quickly settles into a cleaner, more candied apple character. As it dries down, a subtle banana-like creaminess emerges, though the dominant impression remains crisp and fruity. The dry-down is surprisingly tenacious for such a bright note, leaving a faint apple core impression that blends well with woody and floral bases.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as the primary apple accord, providing the photorealistic green apple peel effect that defines this fragrance. The synthetic nature allows the note to remain stable throughout wear.
Showcases butyl isovalerate’s pure apple character without interference from complex bases, demonstrating its versatility as a single-note fragrance component.
2D Molecular Structure
SMILES: CCCCOC(=O)CC(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Butyl isovalerate is an ester formed from butanol and isovaleric acid. While found in trace amounts in some fruits, commercial production is entirely synthetic via acid-catalyzed esterification. The molecule lacks chiral centers, making stereochemistry irrelevant for its olfactory properties. Its relatively simple structure contributes to both its volatility (making it an excellent top note) and its stability in formulations.
Physical & Chemical Properties
| Boiling Point | 184-186 °C |
|---|---|
| Density | 0.86 g/cm³ |
| Refractive Index | 1.406-1.409 |
| Flash Point | 62 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Apple top note |
| Functional Fragrance | 0.1-1% | Up to 3% | Candies, gums |
Classic Accords
Tip: Use with bergamot or lime to enhance the fresh fruit character without overpowering the apple note.
Alternatives & Comparisons
Similar apple character but with greater tenacity and a slightly more ripe fruit quality. Use when longer-lasting apple notes are needed.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions. Not listed in any amendments.
RIFM Assessment
RIFM assessment confirms safe use at current industry levels.
Sustainability
As a synthetic material, butyl isovalerate has minimal environmental impact in production compared to natural apple extracts which require significant agricultural resources. Its efficient synthesis from petrochemical feedstocks makes it a sustainable choice for consistent apple notes without seasonal variability.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090869
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 109-19-3Physical Properties
| Molecular Weight | 158.24 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.6🔬 PubChem |
| Boiling Point | 150 °C🔬 EPA CompTox |
| Flash Point | 53 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.819💻 Calculated |
| SMILES | CCCCOC(=O)CC(C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
Odor & Flavor
| Primary Descriptors | applebananaetherealfruity• leffingwell |
| Functional Groups | esterether💻 RDKit |
| Butyl isovalerate has an odor reminiscent of the isobutyl ester with a sweet, apple-like taste.📖 Fenaroli | |
Sensory Thresholds
| Odor Detection Threshold | 0.078 ppm📖 van Gemert |
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: DTXSID9047621
Physical Properties
| Molecular Weight | 158.241 g/mol🔬 EPA CompTox |
| Density | 0.864 g/cm^3🔬 EPA CTX |
| Boiling Point | 162.25 °C🔬 EPA CTX |
| Melting Point | -70.393 °C📊 OPERA |
| Flash Point | 57.975 °C🔬 EPA CTX |
| Refractive Index | 1.417 Dimensionless📊 OPERA |
| Molar Volume | 180.955 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.072 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.072 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.072 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.43 Log10 unitless📊 OPERA |
| Water Solubility | 0.003 mol/L📊 OPERA |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 1.202 mmHg📊 OPERA |
| Viscosity | 1.082 cP📊 OPERA |
| Surface Tension | 25.631 dyn/cm📊 OPERA |
| Thermal Conductivity | 132.4 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 | 45.478 cm^3/mol📊 OPERA |
| Polarizability | 18.029 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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