Cyclopentanol, 2-(2-hexen-1-yl)- (CAS 34686-67-4) — Green Top Note Fragrance Ingredient
Cyclopentanol, 2-(2-hexen-1-yl)-
CAS 34686-67-4
What Is Cyclopentanol, 2-(2-hexen-1-yl)-?
Cyclopentanol, 2-(2-hexen-1-yl)- is a synthetic fragrance ingredient used to add green, fresh notes to perfumes. It’s found in modern floral and citrus fragrances. This molecule matters because it provides stability and longevity to top notes, helping bright scents last longer on skin.
Safety Profile
GENERALLY SAFEWhat Does Cyclopentanol, 2-(2-hexen-1-yl)- Smell Like?
A crisp, green-aldehydic aroma with subtle citrus undertones. Opens with a sharp, almost metallic freshness reminiscent of crushed leaves, evolving into a smoother, slightly floral heart. The dry-down reveals a faint woody character, like the memory of a forest after rain. Works exceptionally well to ‘lift’ brighter notes in compositions.
2D Molecular Structure
SMILES: CCCC=CCC1CCCC1C
Chemistry, Properties & Perfumer Guide
The Chemistry
A synthetic alicyclic alcohol with a hexenyl side chain. While not found in nature, it’s structurally similar to some green leaf volatiles. Typically produced through hydroformylation or Grignard reactions. The double bond in the side chain offers reactivity for further modification.
Physical & Chemical Properties
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Green note enhancer |
| Functional Fragrances | 0.1-1% | Up to 3% | Freshness booster |
Classic Accords
Tip: Use with citrus oils to prevent excessive sharpness.
Alternatives & Comparisons
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA.
RIFM Assessment
No RIFM safety assessment currently available.
Sustainability
Synthetic production avoids agricultural impacts. Energy-intensive manufacturing requires careful process optimization. Not known to bioaccumulate.
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Ingredient Data Sheet
CAS 34686-67-4Physical Properties
| Molecular Weight | 168.28 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3🔬 PubChem |
| Boiling Point | 226 °C🔬 EPA CompTox |
| Vapor Pressure | 0.8511 mmHg @ 25°C📊 OPERA |
| Flash Point | 73.9 °C🔬 EPA CompTox |
| Involatility Index | 0.0707💻 Calculated |
| log Kp (skin permeability) | -1.597💻 Calculated |
| SMILES | CCCC=CCC1CCCC1O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Functional Groups | alcoholalkene💻 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: DTXSID2052025
Physical Properties
| Molecular Weight | 166.308 g/mol🔬 EPA CompTox |
| Density | 0.814 g/cm^3📊 OPERA |
| Boiling Point | 220.425 °C📊 OPERA |
| Melting Point | -71.539 °C📊 OPERA |
| Flash Point | 76.554 °C📊 OPERA |
| Refractive Index | 1.453 Dimensionless📊 OPERA |
| Molar Volume | 205.921 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 5.555 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 5.555 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 5.555 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.55 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L📊 OPERA |
| Henry's Law Constant | 0.04 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.431 mmHg📊 OPERA |
| Viscosity | 1.723 cP📊 OPERA |
| Surface Tension | 26.359 dyn/cm📊 OPERA |
| Thermal Conductivity | 123.473 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 0 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 0 count💻 Computed |
| Rotatable Bonds | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 55.683 cm^3/mol📊 OPERA |
| Polarizability | 22.074 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.
