Nona-2-trans-6-cis-dienal (CAS 557-48-2) — Green Top to middle Note Fragrance Ingredient
Nona-2-trans-6-cis-dienal
CAS 557-48-2
What Is Nona-2-trans-6-cis-dienal?
Nona-2-trans-6-cis-dienal is a synthetic fragrance ingredient used to add fresh, green, and slightly metallic nuances to perfumes. It’s found in high-end fragrances seeking a crisp, modern edge. This aldehyde contributes to contemporary scent profiles by providing a diffusive, airy quality that enhances citrus and floral compositions without overwhelming them.
Safety Profile
GENERALLY SAFEWhat Does Nona-2-trans-6-cis-dienal Smell Like?
Nona-2-trans-6-cis-dienal opens with a sharp, green burst reminiscent of crushed cucumber peel and freshly cut grass, with a metallic edge like rain on hot pavement. As it evolves, it reveals a cleaner, more aquatic character – imagine dew-covered spiderwebs at dawn. The dry-down is remarkably transparent, leaving just a whisper of waxy aldehydic texture similar to the scent left on fingers after handling green bell peppers.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the razor-sharp freshness of the citrus top notes, creating a ‘diamond dust’ effect that makes the entire composition sparkle with modern clarity.
2D Molecular Structure
SMILES: CC\C=C/CC\C=C\C=O
Chemistry, Properties & Perfumer Guide
The Chemistry
Nona-2-trans-6-cis-dienal is an unsaturated aldehyde with conjugated double bonds. This configuration makes it particularly reactive and light-sensitive. Industrially produced through controlled oxidation of corresponding alcohols or careful aldehyde synthesis, its stereochemistry (trans at position 2, cis at 6) is crucial for odor characteristics. The molecule’s planar structure allows efficient interaction with olfactory receptors.
Physical & Chemical Properties
| Molecular Weight | 140.22 g/mol |
|---|---|
| Boiling Point | ~200 °C (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Provides lift in fresh compositions |
| Functional Fragrance | 0.01-0.1% | Up to 0.3% | Used sparingly in cleaners for green notes |
Classic Accords
Tip: Stabilize with antioxidants to prevent premature oxidation and discoloration.
Alternatives & Comparisons
The all-trans isomer offers similar green character but with more cucumber-like intensity and less metallic sharpness.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA. Listed on IFRA Transparency List.
EU Allergen Declaration
Not listed as EU allergen.
RIFM Assessment
RIFM has completed safety assessment confirming safe use at current industry levels.
Sustainability
As a synthetic material, production requires petrochemical feedstocks but at small scale due to potency. No known ecological accumulation concerns. Future green chemistry routes may utilize bio-based starting materials.
Explore Nona-2-trans-6-cis-dienal
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References
- Brenna et al. (2002). Stereochemistry-odor relationships in unsaturated aldehydes. Journal of Agricultural and Food Chemistry. DOI: 10.1021/jf020230w
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorLayer 3 · Practical
- Odor Profile: cucumber, green, leafy, melon, violet
- FEMA GRAS: 3377
- Molecular Weight: 138.21 g/mol
- LogP (XLogP): 2.20
Ingredient Data Sheet
CAS 557-48-2Physical Properties
| Molecular Weight | 138.21 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.2🔬 PubChem |
| Boiling Point | 94 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.981💻 Calculated |
| SMILES | CCC=CCCC=CC=O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
Odor & Flavor
| Primary Descriptors | cucumbergreenleafymelonviolet• leffingwell |
| Functional Groups | aldehydealkene💻 RDKit |
| “Although this material has been known ●) (see odor description at end of monograph). its enormous power and very peculiar odor type limits its application to Violet, Cucumber cH3—cH~—cH=cH-cH*-cH~-cH bases (e. Extremely powerful and ve “y diffusive The material would particularly be used in green-vegetable odor, only in dilution reminis- imitation Cucumber, and as a trace ingredient cent (striking”📖 Arctander | |
| Nona-2-trans-6-cis-dienal has an odor reminiscent of green cucumber. The organoleptic character of this compound is attributed almost entirely to olfactory sensations. May be obtained from the steam distillation of fresh cucumber. -📖 Fenaroli | |
Sensory Thresholds
| Odor Detection Threshold | 0.0005 ppm (n=13)📖 van Gemert |
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: DTXSID1047104
Physical Properties
| Molecular Weight | 138.21 g/mol🔬 EPA CompTox |
| Density | 0.86 g/cm^3🔬 EPA CTX |
| Boiling Point | 202.335 °C📊 OPERA |
| Melting Point | 10.542 °C📊 OPERA |
| Flash Point | 79.072 °C📊 OPERA |
| Refractive Index | 1.457 Dimensionless📊 OPERA |
| Molar Volume | 161.644 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.712 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.712 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.712 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.43 Log10 unitless📊 OPERA |
| Water Solubility | 0.008 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.363 mmHg📊 OPERA |
| Viscosity | 0.987 cP📊 OPERA |
| Surface Tension | 28.511 dyn/cm📊 OPERA |
| Thermal Conductivity | 145.15 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 | 5 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 44.047 cm^3/mol📊 OPERA |
| Polarizability | 17.462 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.
