6,6-Dimethoxy-2,5,5-trimethylhex-2-ene (CAS 67674-46-8) — Green Top Note Fragrance Ingredient
6,6-Dimethoxy-2,5,5-trimethylhex-2-ene
CAS 67674-46-8
What Is 6,6-Dimethoxy-2,5,5-trimethylhex-2-ene?
6,6-Dimethoxy-2,5,5-trimethylhex-2-ene is a synthetic aroma chemical used in modern perfumery. It imparts fresh, green, and slightly woody nuances. You’ll encounter it in contemporary fragrances seeking crisp, naturalistic effects without using actual plant extracts. This matters because it allows perfumers to create sustainable, consistent green accords while avoiding seasonal variability or agricultural challenges of natural materials.
Safety Profile
GENERALLY SAFEWhat Does 6,6-Dimethoxy-2,5,5-trimethylhex-2-ene Smell Like?
This molecule delivers an intriguing duality – opening with the sharp snap of freshly broken stems (imagine snapping a green bean in half) before transitioning to a smoother, slightly fruity woodiness reminiscent of unripe kiwi skin. The dry-down reveals a whisper of damp moss on sun-warmed stones. Its linear character makes it excellent for creating stable green top notes that don’t shift unpredictably.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to reconstruct the iconic galbanum burst in the reformulation, providing a modern green sharpness that lasts longer than traditional materials.
Contributes to the razor-sharp violet leaf illusion in the opening, enhancing the metallic freshness without adding excessive sweetness.
2D Molecular Structure
SMILES: COC(OC)C(C)(C)CC=C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
A synthetic alkene with two methoxy groups positioned at the 6-carbon position. The trimethylhexene backbone provides structural stability while the methoxy groups contribute polar character. Typically synthesized through controlled oxidation of corresponding terpene precursors followed by methoxylation. The specific stereochemistry at the double bond significantly impacts odor profile – perfumery grade requires high (E)-isomer purity.
Physical & Chemical Properties
| Boiling Point | ~200 °C (estimated) |
|---|---|
| Density | ~0.89 g/cm³ (estimated) |
| Vapor Pressure | Low (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Green top note enhancer |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Provides naturalistic freshness |
Classic Accords
Tip: Use with citrus top notes to prevent excessive sharpness.
Alternatives & Comparisons
When a more pronounced leafy, cucumber-like effect is desired without the woody undertones.
For stronger green, grassy character with higher diffusion but shorter longevity.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under IFRA 49th Amendment. Approved for all standard fragrance applications.
EU Allergen Declaration
Not listed in EU allergen regulation (EC) No 1223/2009.
RIFM Assessment
RIFM safety assessment completed – no significant concerns at standard usage levels.
Sustainability
Synthetic production avoids agricultural land use and seasonal variability. The manufacturing process employs green chemistry principles with >85% atom economy. Biodegradability studies show moderate environmental persistence (60% degradation in 28 days).
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References
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 67674-46-8Physical Properties
| Molecular Weight | 186.29 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.2🔬 PubChem |
| Boiling Point | 214 °C🔬 EPA CompTox |
| Vapor Pressure | 0.12 mmHg @ 25°C📊 OPERA |
| Flash Point | 73 °C🔬 EPA CompTox |
| Involatility Index | 0.0095💻 Calculated |
| log Kp (skin permeability) | -1.564💻 Calculated |
| SMILES | CC(=CCC(C)(C)C(OC)OC)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 1.7 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | citrusfreshgrapefruit• leffingwell |
| Functional Groups | etheralkene💻 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: DTXSID2052366
Physical Properties
| Molecular Weight | 186.295 g/mol🔬 EPA CompTox |
| Density | 0.877 g/cm^3🔬 EPA CTX |
| Boiling Point | 207.75 °C🔬 EPA CTX |
| Melting Point | -45.041 °C📊 OPERA |
| Flash Point | 73 °C🔬 EPA CTX |
| Refractive Index | 1.433 Dimensionless📊 OPERA |
| Molar Volume | 216.675 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.228 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.228 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.228 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.01 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.176 mmHg🔬 EPA CTX |
| Viscosity | 1.349 cP📊 OPERA |
| Surface Tension | 24.805 dyn/cm📊 OPERA |
| Thermal Conductivity | 118.716 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 18.46 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 5 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 56.326 cm^3/mol📊 OPERA |
| Polarizability | 22.329 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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