8-Undecenal (CAS 58296-81-4) — Citrus Top Note Fragrance Ingredient
8-Undecenal
CAS 58296-81-4
What Is 8-Undecenal?
8-Undecenal is a synthetic fragrance molecule with a powerful citrusy, waxy-green odor reminiscent of fresh cucumber peels. Used in minute quantities to add crispness to fruity florals and modern colognes. This aldehyde requires careful handling due to its potency, but when properly diluted, it creates sparkling top notes that elevate everyday products from shampoos to luxury perfumes.
Safety Profile
USE WITH AWARENESSWhat Does 8-Undecenal Smell Like?
8-Undecenal bursts with an almost electric citrus-green intensity, like scraping a cucumber with a zester while standing in a grove of unripe oranges. The initial waxy-aldehydic punch mellows into a clean, aquatic freshness over 30 minutes, leaving a faint trail reminiscent of watermelon rind and freshly cut grass. At ultra-low concentrations, it adds an elusive ‘just-showered’ crispness to fragrances.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used sparingly to amplify the citrus opening, contributing to that legendary ‘just-shaved’ freshness. The aldehyde’s green facets bridge between bergamot and herbal notes.
Jean-Claude Ellena employed 8-undecenal to create the illusion of snapping green mango stems, blending it with grapefruit and lotus for an aqueous, sun-drenched effect.
2D Molecular Structure
SMILES: CCC=CCCCCCCC=O
Chemistry, Properties & Perfumer Guide
The Chemistry
8-Undecenal is an unsaturated aldehyde (C11H20O) belonging to the family of long-chain aliphatic aldehydes. Industrially produced via hydroformylation of 1-decene followed by selective oxidation. The double bond at position 8 creates distinctive reactivity patterns. Modern synthesis routes emphasize atom economy to reduce heavy metal catalyst residues.
Physical & Chemical Properties
| Boiling Point | 235 °C |
|---|---|
| Flash Point | >100 °C |
| Vapor Pressure | 0.01 mmHg at 25°C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.01-0.1% | Up to 0.3% | Overdosing causes waxy off-notes |
| Functional Products | 0.001-0.01% | Up to 0.05% | Adds freshness to detergents |
Classic Accords
Tip: Pre-dilute to 1% in DPG before incorporation to ensure even distribution.
Alternatives & Comparisons
Less aggressive green character, better for floral compositions needing subtle freshness without the cucumber peel intensity.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under IFRA 49th Amendment.
GHS Classification
RIFM Assessment
RIFM assessment completed in 2010 – safe for use at current levels in fragrance.
Sustainability
Synthesized from petrochemical feedstocks, though newer bio-based routes using renewable decene are under development. The fragrance industry is investigating enzymatic oxidation methods to reduce environmental impact of aldehyde production.
Explore 8-Undecenal
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References
- Bickers et al. (2003). The safety assessment of fragrance ingredients. Food and Chemical Toxicology. PubChem CID
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 58296-81-4Physical Properties
| Molecular Weight | 168.28 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.4🔬 PubChem |
| Boiling Point | 220 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0209 mmHg @ 25°C📊 OPERA |
| Flash Point | 99.5 °C🔬 EPA CompTox |
| Involatility Index | 0.0017💻 Calculated |
| log Kp (skin permeability) | -1.313💻 Calculated |
| SMILES | CCC=CCCCCCCC=O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 3.2 / 5💻 Calculated |
Odor & Flavor
| Functional Groups | aldehydealkene💻 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: DTXSID6052243
Physical Properties
| Molecular Weight | 168.28 g/mol🔬 EPA CompTox |
| Density | 0.846 g/cm^3📊 OPERA |
| Boiling Point | 228.463 °C📊 OPERA |
| Melting Point | 2.279 °C📊 OPERA |
| Flash Point | 98.744 °C📊 OPERA |
| Refractive Index | 1.443 Dimensionless📊 OPERA |
| Molar Volume | 201.043 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.947 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.947 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.947 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.83 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.051 mmHg📊 OPERA |
| Viscosity | 1.837 cP📊 OPERA |
| Surface Tension | 28.835 dyn/cm📊 OPERA |
| Thermal Conductivity | 145.562 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 17.07 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 8 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 53.255 cm^3/mol📊 OPERA |
| Polarizability | 21.112 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.
