2,6,6-Trimethylcyclohexa-1,3-dienyl methanal (CAS 116-26-7) — Woody Top to middle Note Fragrance Ingredient
2,6,6-Trimethylcyclohexa-1,3-dienyl methanal
CAS 116-26-7
What Is 2,6,6-Trimethylcyclohexa-1,3-dienyl methanal?
2,6,6-Trimethylcyclohexa-1,3-dienyl methanal is a synthetic fragrance ingredient used in perfumery to create fresh, green, and woody accords. It’s found in modern floral and fougère compositions. This molecule contributes a crisp, diffusive quality that helps brighten fragrance openings while adding structural complexity to heart notes.
Safety Profile
USE WITH AWARENESSWhat Does 2,6,6-Trimethylcyclohexa-1,3-dienyl methanal Smell Like?
This synthetic aldehyde delivers a vibrant, green-woody character with citrusy undertones. Initially sharp and diffusive like crushed stems, it evolves into a drier, more ambery woodiness reminiscent of freshly sanded cedar. The dry-down reveals subtle floral nuances that bridge between green top notes and woody base materials. Its moderate tenacity makes it valuable for creating dynamic scent transitions.
2D Molecular Structure
SMILES: CC1=C(C=O)C(C)(C)CC=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
2,6,6-Trimethylcyclohexa-1,3-dienyl methanal belongs to the cyclohexadiene aldehyde class, synthesized through Diels-Alder reactions or oxidation of corresponding alcohols. Its conjugated diene system contributes to both stability and olfactory character. The molecule’s rigid cyclic structure prevents free rotation, creating distinct stereochemical effects that influence its odor profile and volatility.
Physical & Chemical Properties
| Molecular Class | Cyclohexadiene aldehyde |
|---|---|
| Volatility | Medium-high |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Green-woody modifier |
| Functional Fragrance | 0.1-1% | Up to 3% | Freshness booster |
Classic Accords
Tip: Use with citrus top notes to enhance diffusion without overpowering delicate florals.
Alternatives & Comparisons
Softer floral-aldehydic alternative with better blending in white floral compositions.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No current IFRA restrictions. Listed on IFRA Transparency List.
RIFM Assessment
Under review by RIFM. Preliminary data suggests low sensitization potential.
Sustainability
As a synthetic material, production avoids agricultural land use. Manufacturing typically employs green chemistry principles with high atom economy. Potential exists for bio-based production routes using terpene feedstocks.
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References
- Brenna et al. (2012). Cyclic aldehydes in modern perfumery. Flavour and Fragrance Journal.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 116-26-7Physical Properties
| Molecular Weight | 150.22 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.1🔬 PubChem |
| Boiling Point | 70 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0773 mmHg @ 25°C📊 OPERA |
| Flash Point | 84.9 °C🔬 EPA CompTox |
| Involatility Index | 0.0068💻 Calculated |
| log Kp (skin permeability) | -2.125💻 Calculated |
| SMILES | CC1=C(C(CC=C1)(C)C)C=O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 1.7 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | camphoraceoustobacco• leffingwell |
| Functional Groups | aldehydealkene💻 RDKit |
| “Very powerful, sweet, green-floral and somewhat tobacco-herbaceous odor of good tenacity. In extreme dilution reminiscent of the odor of Safran (Saffron).”📖 Arctander | |
| 2,6,6-Trimethylcyclohexa-1,3-dienyl methanal has a characteristic saffron-like odor and taste.📖 Fenaroli | |
Flavor Notes (Arctander)
| “The aldehyde is, to the author's knowledge, not used extensively in flavor compositions.”📖 Arctander |
Regulatory Status
| IFRA Listed | Yes — see IFRA Standards for category limits⚖️ IFRA 51 |
| 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: DTXSID7049398
Physical Properties
| Molecular Weight | 150.221 g/mol🔬 EPA CompTox |
| Density | 0.97 g/cm^3🔬 EPA CTX |
| Boiling Point | 221.771 °C📊 OPERA |
| Melting Point | 38.977 °C📊 OPERA |
| Flash Point | 84.9 °C🔬 EPA CTX |
| Refractive Index | 1.529 Dimensionless📊 OPERA |
| Molar Volume | 154.009 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.569 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.569 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.569 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5 Log10 unitless📊 OPERA |
| Water Solubility | 0.003 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.077 mmHg🔬 EPA CTX |
| Viscosity | 1.327 cP📊 OPERA |
| Surface Tension | 34.737 dyn/cm📊 OPERA |
| Thermal Conductivity | 118.778 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 | 1 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 47.508 cm^3/mol📊 OPERA |
| Polarizability | 18.834 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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