2-Undecanol (CAS 1653-30-1) — Citrus Top/Middle Note Fragrance Ingredient
2-Undecanol
CAS 1653-30-1
What Is 2-Undecanol?
2-Undecanol is a synthetic alcohol used in perfumery to add fresh, citrus-like notes with a waxy undertone. You might encounter it in light floral or cologne-type fragrances. This ingredient matters because it provides a clean, slightly fruity aroma that bridges citrus and floral accords without being overpowering, making it useful for creating balanced top notes in modern perfumes.
Safety Profile
GENERALLY SAFEWhat Does 2-Undecanol Smell Like?
2-Undecanol opens with a bright, citrusy freshness reminiscent of lemon peel and grapefruit, though more subdued. As it evolves, it reveals a waxy, slightly floral character akin to orange blossoms dipped in beeswax. The dry-down is clean and mildly soapy, leaving a soft, skin-like musk impression. Unlike sharper citrus compounds, it maintains a rounded quality throughout its evolution, making it particularly useful for smoothing harsh edges in fresh compositions.
2D Molecular Structure
SMILES: CCCCCCCCCC(C)O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Undecanol is a secondary alcohol with an 11-carbon chain. It’s produced synthetically through the hydroformylation of 1-decene followed by hydrogenation. The molecule’s chirality at the second carbon position can influence its odor profile, with different enantiomers exhibiting slightly varying intensity and character. While not found abundantly in nature, trace amounts may occur in some fermented products.
Physical & Chemical Properties
| Boiling Point | Not available |
|---|---|
| Density | Not available |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | Up to 5% | Fresh top note modifier |
| Functional Fragrance | 0.5-2% | Up to 3% | Soapy-clean accent |
| Cosmetics | 0.1-1% | Up to 2% | Light freshness booster |
Classic Accords
Tip: Use to soften harsh citrus notes while maintaining freshness in top accords.
Alternatives & Comparisons
Primary alcohol version with stronger waxy character but less citrus freshness.
More floral and rosy, though with similar freshness and blending properties.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions apply to 2-Undecanol under current guidelines.
RIFM Assessment
Not currently assessed by RIFM, but structurally similar alcohols show low concern profiles.
Sustainability
As a synthetic material, 2-Undecanol production doesn’t rely on agricultural resources. Its manufacturing process is typical for mid-chain alcohols, with moderate energy requirements. Being petroleum-derived, its environmental footprint depends on the sustainability practices of the petrochemical source.
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Ingredient Data Sheet
CAS 1653-30-1Physical Properties
| Molecular Weight | 172.31 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 4.5🔬 PubChem |
| Boiling Point | 232 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0093 mmHg @ 25°C📊 OPERA |
| Flash Point | 107 °C🔬 EPA CompTox |
| Involatility Index | 0.0008💻 Calculated |
| log Kp (skin permeability) | -0.556💻 Calculated |
| SMILES | CCCCCCCCCC(C)O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 4.4 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | fattyfruity• leffingwell |
| Functional Groups | alcohol💻 RDKit |
| “Its taste is more pleasant than its odor, the fatty notes apparently subdued and the fruity-nutty, sweeter notes enhanced at concentrations around 10 ppm.”📖 Arctander | |
| 2-Undecanol has a fatty odor with a fruity note. A fruity taste is also detectable at low concentration.📖 Fenaroli | |
Flavor Notes (Arctander)
| “This alcohol finds limited use in flavor compositions, often in imitation Coconut, sometimes traces in Rum or Brandy flavors. Its taste is more pleasant than its odor, the fatty notes apparently subdued and the fruity-nutty, sweeter notes enhanced at concentrations around 10 ppm.”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.0188 ppm (n=2)📖 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: DTXSID2058673
Physical Properties
| Molecular Weight | 172.312 g/mol🔬 EPA CompTox |
| Density | 0.83 g/cm^3🔬 EPA CTX |
| Boiling Point | 232.5 °C🔬 EPA CTX |
| Melting Point | -1.278 °C🔬 EPA CTX |
| Flash Point | 107 °C🔬 EPA CTX |
| Refractive Index | 1.437 Dimensionless📊 OPERA |
| Molar Volume | 207.992 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.42 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 4.594 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.594 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.72 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.021 mmHg🔬 EPA CTX |
| Viscosity | 11.26 cP📊 OPERA |
| Surface Tension | 28.258 dyn/cm📊 OPERA |
| Thermal Conductivity | 150.6 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 20.23 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 8 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 54.504 cm^3/mol📊 OPERA |
| Polarizability | 21.607 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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