3,6-Dimethyl-3-cyclohexene-1-carboxaldehyde (CAS 67801-65-4) — Green Top to middle Note Fragrance Ingredient
3,6-Dimethyl-3-cyclohexene-1-carboxaldehyde
CAS 67801-65-4
What Is 3,6-Dimethyl-3-cyclohexene-1-carboxaldehyde?
3,6-Dimethyl-3-cyclohexene-1-carboxaldehyde is a synthetic fragrance ingredient used in modern perfumery to create fresh, green, and slightly woody scents. You’ll encounter it in air fresheners, fabric softeners, and some contemporary perfumes. This aldehyde matters because it adds a crisp, clean character to fragrances, helping to bridge floral and woody notes without being overpowering. Its subtle complexity makes it valuable for creating nuanced scent profiles in everyday products.
Safety Profile
USE WITH AWARENESSWhat Does 3,6-Dimethyl-3-cyclohexene-1-carboxaldehyde Smell Like?
This aldehyde opens with a burst of crisp greenness reminiscent of crushed stems and dewy leaves, with a subtle metallic edge like rain on hot pavement. As it evolves, a transparent woody character emerges – imagine the pale heartwood of young birch trees. The dry-down reveals faint floral undertones, as if a single lily of the valley bloom were placed in a freshly sanded wooden box. Throughout its progression, it maintains an airy quality, never becoming heavy or sweet, making it ideal for modern aquatic and fougère compositions.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the fresh aquatic character, adding a green-transparent facet that complements the marine notes without competing with the lavender heart.
Provides a crisp green contrast to the citrus opening, creating the illusion of wind through Mediterranean herbs before the woody base emerges.
2D Molecular Structure
SMILES: CC1CC=C(C)CC1C=O
Chemistry, Properties & Perfumer Guide
The Chemistry
3,6-Dimethyl-3-cyclohexene-1-carboxaldehyde belongs to the cyclohexene carboxaldehyde class, characterized by a six-membered ring with one double bond and an aldehyde functional group. The molecule features two methyl groups at positions 3 and 6, which influence its volatility and odor characteristics. Industrially synthesized through Diels-Alder reactions followed by oxidation, this compound demonstrates how small structural modifications (like methyl group positioning) can significantly alter scent profiles. The molecule’s rigidity from the ring structure contributes to its moderate persistence in fragrance formulations.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Approx. 210-220°C (estimated) |
| Density | ~0.92-0.95 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used for fresh top notes |
| Functional Fragrance | 1-3% | Up to 8% | Adds clean character to detergents |
Classic Accords
Tip: Use with ionones to create a seamless transition between green top notes and woody base notes.
Alternatives & Comparisons
Offers similar green floralcy but with more powderiness and less woody character, better suited for floral bouquets.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted under IFRA standards. Monitor for future amendments as aldehydes are frequently reassessed.
GHS Classification
RIFM Assessment
Under review by RIFM as part of ongoing aldehyde safety assessments.
Sustainability
As a purely synthetic material, this ingredient avoids natural resource depletion but requires petrochemical feedstocks. Green chemistry approaches are being explored to synthesize similar molecules from renewable resources. Its moderate potency means relatively small quantities are needed in formulations, reducing overall environmental impact compared to less powerful materials.
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References
- Brenna et al. (2012). Structure-Odor Relationships in Cyclohexene Carboxaldehydes. Journal of Agricultural and Food Chemistry.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID1052377
Physical Properties
| Molecular Weight | 138.21 g/mol🔬 EPA CompTox |
| Density | 0.946 g/cm^3📊 OPERA |
| Boiling Point | 191.662 °C📊 OPERA |
| Melting Point | -0.27 °C📊 OPERA |
| Flash Point | 63.399 °C📊 OPERA |
| Refractive Index | 1.512 Dimensionless📊 OPERA |
| Molar Volume | 144.3 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.711 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.711 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.711 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.32 Log10 unitless📊 OPERA |
| Water Solubility | 0.009 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.466 mmHg📊 OPERA |
| Viscosity | 2.105 cP📊 OPERA |
| Surface Tension | 34.448 dyn/cm📊 OPERA |
| Thermal Conductivity | 125.723 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 | 43.295 cm^3/mol📊 OPERA |
| Polarizability | 17.164 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.
