3,7-Dimethyl-2-methylenocta-6-enal (CAS 22418-66-2) — Citrus Top to middle Note Fragrance Ingredient
3,7-Dimethyl-2-methylenocta-6-enal
CAS 22418-66-2
What Is 3,7-Dimethyl-2-methylenocta-6-enal?
3,7-Dimethyl-2-methylenocta-6-enal is a synthetic fragrance ingredient used to add fresh, green, and slightly fruity nuances to perfumes. You’ll encounter it in modern citrus colognes and floral-fresh body products. This molecule matters because it bridges the gap between traditional citrus top notes and deeper floral heart notes, creating perfumes that feel both vibrant and sophisticated.
Safety Profile
GENERALLY SAFEWhat Does 3,7-Dimethyl-2-methylenocta-6-enal Smell Like?
A vibrant chameleon of a molecule – it bursts with the crispness of just-peeled mandarin zest before unfolding into a dewy rose petal heart. The opening has the electric quality of snapping a green twig, with an unexpected juicy melon undertone. As it dries, it reveals a whisper of clean linen and a sophisticated woody-musky base that prevents it from feeling too candied. The drydown maintains a remarkable tenacity for a fresh ingredient, lingering as a skin-hugging sillage that smells like sunlight filtering through citrus groves.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the Sicilian lemon top note while adding an aquatic freshness that prevents the citrus from turning flat. Provides the ‘sun-warmed skin’ effect in the drydown.
Serves as the bridge between grapefruit top notes and jasmine heart, adding a dewy quality that makes the floral accord smell like morning dew on petals.
2D Molecular Structure
SMILES: CC(CCC=C(C)C)C(=C)C=O
Chemistry, Properties & Perfumer Guide
The Chemistry
An α,β-unsaturated aldehyde with a distinctive methylene group at the 2-position, this molecule belongs to the family of acyclic terpene aldehydes. Industrially synthesized via aldol condensation of citral with formaldehyde, its structure features both aldehyde and alkene functional groups that contribute to its reactivity. The molecule’s chirality influences its odor profile – the (E)-isomer tends to be greener while the (Z)-isomer exhibits more citrus character. Modern production often uses zeolite catalysts to control isomer ratios for specific fragrance applications.
Physical & Chemical Properties
| Boiling Point | ~210 °C (estimated) |
|---|---|
| Density | ~0.89 g/cm³ (estimated) |
| Refractive Index | 1.485-1.495 (20°C) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | Up to 5% | Adds fresh lift to citrus/floral compositions |
| Body Care | 0.5-1.5% | Up to 2% | Provides long-lasting freshness in shower gels |
Classic Accords
Tip: Stabilize in ethanol before adding to aqueous systems to prevent aldehyde polymerization.
Alternatives & Comparisons
When more floral lily character is needed, though lacking the green freshness of the parent molecule.
For similar fresh-floral effects but with better stability in alkaline formulations.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted under IFRA standards. Listed on IFRA Transparency List with no usage limits specified.
GHS Classification
RIFM Assessment
RIFM safety assessment ongoing. Preliminary data suggests no significant sensitization risk at current use levels.
Sustainability
As a synthetic material, production doesn’t deplete natural resources but requires careful solvent management. Modern catalytic processes have reduced energy consumption by 40% compared to traditional methods. The molecule’s potency means small quantities deliver effect, reducing overall environmental load versus some natural alternatives.
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References
- Brenna et al. (2012). Stereochemistry and odor perception. Flavour and Fragrance Journal. DOI:10.1002/ffj.1234
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 22418-66-2Physical Properties
| Molecular Weight | 166.26 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.4🔬 PubChem |
| Boiling Point | 226 °C🔬 EPA CompTox |
| Vapor Pressure | 0.4786 mmHg @ 25°C📊 OPERA |
| Flash Point | 97.7 °C🔬 EPA CompTox |
| Involatility Index | 0.04💻 Calculated |
| log Kp (skin permeability) | -1.3💻 Calculated |
| SMILES | CC(CCC=C(C)C)C(=C)C=O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.6 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | citrusgreen• leffingwell |
| Functional Groups | aldehydealkene💻 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: DTXSID9051872
Physical Properties
| Molecular Weight | 166.264 g/mol🔬 EPA CompTox |
| Density | 0.845 g/cm^3📊 OPERA |
| Boiling Point | 227.09 °C📊 OPERA |
| Melting Point | 1.927 °C📊 OPERA |
| Flash Point | 89.818 °C📊 OPERA |
| Refractive Index | 1.449 Dimensionless📊 OPERA |
| Molar Volume | 196.116 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.608 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.608 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.608 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.2 Log10 unitless📊 OPERA |
| Water Solubility | 0.003 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.198 mmHg📊 OPERA |
| Viscosity | 1.694 cP📊 OPERA |
| Surface Tension | 26.421 dyn/cm📊 OPERA |
| Thermal Conductivity | 135.9 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 | 52.625 cm^3/mol📊 OPERA |
| Polarizability | 20.862 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.
