2,6-Octadienal, 3,6,7-trimethyl- (CAS 1891-67-4) — Green Top Note Fragrance Ingredient
2,_6-_Octadienal, 3,_6,_7-_trimethyl-
CAS 1891-67-4
What Is 2,_6-_Octadienal, 3,_6,_7-_trimethyl-?
2,6-Octadienal, 3,6,7-trimethyl- is a synthetic fragrance ingredient used to add fresh, green, and slightly floral nuances to perfumes. It’s commonly found in modern floral and citrus fragrances. This molecule matters because it can mimic natural green notes without relying on plant extracts, offering consistency and sustainability benefits in fragrance formulation.
Safety Profile
GENERALLY SAFEWhat Does 2,_6-_Octadienal, 3,_6,_7-_trimethyl- Smell Like?
This molecule opens with a burst of fresh-cut grass and cucumber peel, like walking through a dew-covered garden at dawn. As it evolves, the green sharpness softens into a delicate floral undertone reminiscent of lily-of-the-valley, before settling into a clean, slightly woody dry-down. The overall effect is like a sunbeam piercing through a greenhouse – vibrant yet transparent.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to create the crisp, refreshing top note that mimics freshly brewed green tea leaves, providing an authentic vegetal accent.
Employed as a green modifier to enhance the watery mango accord, adding dimension to the tropical fruit notes.
2D Molecular Structure
SMILES: CC(C)=C(C)CCC(C)=CC=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2,6-Octadienal, 3,6,7-trimethyl- belongs to the family of unsaturated aldehydes. While not found in nature, it’s structurally related to compounds like citral. Synthesized through aldol condensation reactions, this molecule’s conjugated double bond system contributes to its fresh green character. The trimethyl substitution pattern prevents the harshness often associated with simpler unsaturated aldehydes.
Physical & Chemical Properties
| Boiling Point | Not available |
|---|---|
| Density | Not available |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Green accent note |
| Functional Fragrances | 0.1-0.5% | Up to 1% | Freshness booster |
Classic Accords
Tip: Use to brighten floral compositions or add naturalistic green effects without heaviness.
Alternatives & Comparisons
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions currently apply to this material.
RIFM Assessment
RIFM has not published a specific safety assessment for this material as of 2023.
Sustainability
As a synthetic material, this ingredient avoids agricultural land use and seasonal variability. Its production can be optimized for minimal waste, though energy inputs for synthesis should be considered. Being used at low concentrations reduces environmental load.
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References
- PubChem Compound Summary CID N/A
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 1891-67-4Physical Properties
| Molecular Weight | 166.26 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.7🔬 PubChem |
| Boiling Point | 229 °C🔬 EPA CompTox |
| Vapor Pressure | 0.5012 mmHg @ 25°C📊 OPERA |
| Flash Point | 104.4 °C🔬 EPA CompTox |
| Involatility Index | 0.0419💻 Calculated |
| log Kp (skin permeability) | -1.087💻 Calculated |
| SMILES | CC(=C(C)CCC(=CC=O)C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.6 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | floralgreen• leffingwell |
| Functional Groups | aldehydealkene💻 RDKit |
| “Sweet and refreshing Lemon-like fruity odor of moderate tenacity. Not nearly as "lemony" as Citral, but sweeter. Does not have the initial "punch" often observed in commercial grade Citral, and the Methylcitral is more tenacious. Overall less versatile than Citral.”📖 Arctander | |
Regulatory Status
| IFRA Listed | Yes — see IFRA Standards for category limits⚖️ IFRA 51 |
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: DTXSID30883767
Physical Properties
| Molecular Weight | 166.264 g/mol🔬 EPA CompTox |
| Density | 0.861 g/cm^3📊 OPERA |
| Boiling Point | 234.466 °C📊 OPERA |
| Melting Point | 10.297 °C📊 OPERA |
| Flash Point | 94.185 °C📊 OPERA |
| Refractive Index | 1.457 Dimensionless📊 OPERA |
| Molar Volume | 194.061 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.47 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.47 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.47 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.78 Log10 unitless📊 OPERA |
| Water Solubility | 0.005 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.211 mmHg📊 OPERA |
| Viscosity | 1.649 cP📊 OPERA |
| Surface Tension | 25.744 dyn/cm📊 OPERA |
| Thermal Conductivity | 135.542 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 | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 52.841 cm^3/mol📊 OPERA |
| Polarizability | 20.948 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.
