2-Ethylbutyl cyclopent-2-ene-1-acetate (CAS 94278-39-4) — Green Top to middle Note Fragrance Ingredient
2-Ethylbutyl cyclopent-2-ene-1-acetate
CAS 94278-39-4
What Is 2-Ethylbutyl cyclopent-2-ene-1-acetate?
2-Ethylbutyl cyclopent-2-ene-1-acetate is a synthetic fragrance ingredient used in modern perfumery. It contributes to fruity, green, and woody accords. You might encounter it in fresh, contemporary fragrances designed for everyday wear. This ingredient matters because it adds complexity and longevity to scent compositions, helping perfumers create unique olfactory experiences that evolve beautifully on the skin.
Safety Profile
GENERALLY SAFEWhat Does 2-Ethylbutyl cyclopent-2-ene-1-acetate Smell Like?
This synthetic molecule offers a vibrant, fruity-green character with woody undertones. Imagine the crispness of unripe apples meeting the sappy freshness of crushed pine needles, rounded by a subtle tropical fruit sweetness. The top note bursts with energetic greenness, transitioning to a heart that reveals juicy pear-like facets. As it dries down, a clean woody-musky base emerges, providing excellent tenacity. The overall effect is modern and versatile – equally at home in fresh citrus colognes as it is in woody-oriental compositions.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to enhance the energizing green-fruity character, pairing with citrus and herbal notes to create an invigorating, tonic-like effect.
Provides crisp green apple facets that complement the tea accord, adding naturalistic fruity freshness to this light, refreshing composition.
Contributes to the luminous green mango accord, helping bridge the citrus top with the woody base in this garden-inspired fragrance.
Used sparingly to reinforce the crisp apple note and add diffusion to this popular fresh floral composition.
Provides subtle fruity-green nuances that enhance the naturalistic coastal vibe without overpowering the delicate marine accord.
2D Molecular Structure
SMILES: CCC(CC)COC(=O)CC1CCC=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Ethylbutyl cyclopent-2-ene-1-acetate belongs to the ester class of fragrance compounds, specifically cyclic terpene esters. While not found in nature, its structure suggests it may share olfactory characteristics with naturally occurring terpenoid esters. The molecule features a cyclopentene ring substituted with an acetate group at position 1 and an ethylbutyl chain at position 2, creating a balanced combination of fruity, green, and woody odor characteristics. Synthesis typically involves esterification of cyclopentene carboxylic acid derivatives with 2-ethylbutanol under acidic conditions.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Estimated 220-240°C |
| Density | Estimated 0.92-0.96 g/cm³ |
| Refractive Index | Estimated 1.45-1.48 |
| Solubility | Soluble in alcohol, oils; insoluble in water |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Green-fruity modifier |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Freshness booster |
| Household Products | 0.05-0.2% | Up to 0.5% | Green top note |
| Personal Care | 0.2-1% | Up to 2% | Freshness component |
Classic Accords
Tip: Use at 0.5-1% in chypre bases to add fruity-green lift without distorting the classic structure.
Alternatives & Comparisons
For simpler fruity-green effects when more diffusion is needed. Lacks the woody depth but offers better top note impact.
When a cleaner, more pronounced green apple character is desired. More tenacious but less fruity.
For brighter, more floral-fruity effects in top notes. Shares some green facets but leans more floral.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA. General usage guidelines apply.
RIFM Assessment
Not currently evaluated by RIFM. Standard safety precautions recommended.
Sustainability
As a synthetic material, this ingredient avoids natural resource depletion concerns. Production can be optimized for minimal environmental impact through green chemistry principles. Being petroleum-derived, its sustainability depends on the manufacturer’s commitment to renewable feedstocks and energy-efficient processes. Proper handling ensures minimal environmental release.
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References
- Bauer, K. et al. (2001). Common Fragrance and Flavor Materials. Wiley-VCH. ISBN 9783527612482
- Arctander, S. (1969). Perfume and Flavor Chemicals. Allured Publishing. Allured
- IFRA Standards Library IFRA
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 94278-39-4Physical Properties
| Molecular Weight | 210.31 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.6🔬 PubChem |
| Boiling Point | 244 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0162 mmHg @ 25°C📊 OPERA |
| Flash Point | 91.5 °C🔬 EPA CompTox |
| Involatility Index | 0.0012💻 Calculated |
| log Kp (skin permeability) | -1.427💻 Calculated |
| SMILES | CCC(CC)COC(=O)CC1CCC=C1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 3.7 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | greenwoody• leffingwell |
| Functional Groups | esteretheralkene💻 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: DTXSID10869226
Physical Properties
| Molecular Weight | 210.317 g/mol🔬 EPA CompTox |
| Density | 0.94 g/cm^3📊 OPERA |
| Boiling Point | 254.238 °C📊 OPERA |
| Melting Point | -16.652 °C📊 OPERA |
| Flash Point | 102.57 °C📊 OPERA |
| Refractive Index | 1.465 Dimensionless📊 OPERA |
| Molar Volume | 222.481 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.32 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.32 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.32 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.63 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.009 mmHg📊 OPERA |
| Viscosity | 4.637 cP📊 OPERA |
| Surface Tension | 31.333 dyn/cm📊 OPERA |
| Thermal Conductivity | 135.696 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 | 6 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 61.52 cm^3/mol📊 OPERA |
| Polarizability | 24.388 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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