2-Hexylidenehexanal (CAS 13019-16-4) — Green Top to middle Note Fragrance Ingredient
2-Hexylidenehexanal
CAS 13019-16-4
What Is 2-Hexylidenehexanal?
2-Hexylidenehexanal is a synthetic fragrance ingredient used in perfumes and scented products to add fresh, green, and slightly floral nuances. It’s often found in modern floral and citrus compositions. This molecule matters because it helps create crisp, natural-smelling accords that mimic outdoor freshness without relying solely on natural extracts, making fragrances more sustainable and consistent.
Safety Profile
GENERALLY SAFEWhat Does 2-Hexylidenehexanal Smell Like?
2-Hexylidenehexanal opens with a sharp, green burst reminiscent of crushed leaves and unripe citrus peel, with a metallic edge like raindrops on aluminum. The heart develops into a cleaner, soapy floralcy akin to lily-of-the-valley stems. As it dries, it leaves a waxy, cucumber-like trail with surprising tenacity for an aldehyde. The overall effect is like walking through a greenhouse at dawn – humid, vegetal, and slightly ozonic.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a modern green substitute for galbanum, amplifying the crushed-leaf effect while adding diffusion.
Provides the crisp ‘alive’ quality in this energizing citrus-aromatic, mimicking fresh-cut herbs.
Contributes to the watery-green mango accord, bridging tropical fruit and vegetal notes.
2D Molecular Structure
SMILES: CCCCCC=C(CCCC)C=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Hexylidenehexanal is an α,β-unsaturated aldehyde with a ten-carbon backbone. As a synthetic molecule, it’s typically produced via aldol condensation of hexanal derivatives, followed by selective hydrogenation. The conjugated double bond system contributes to its green character and reactivity. Unlike many floral aldehydes, this compound lacks significant chirality due to its symmetrical structure.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Solubility | Soluble in alcohol, insoluble in water |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 3% | Green modifier |
| Functional | 0.1-0.5% | Up to 1% | Freshness booster |
Classic Accords
Tip: Stabilize with antioxidants to prevent polymerization during aging.
Alternatives & Comparisons
More intense green-leaf character but shorter-lived. Use when maximum impact is needed.
Softer, waxy-aldehydic alternative when harshness must be avoided.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA. Listed as safe under current guidelines.
RIFM Assessment
Under evaluation – preliminary data suggests low sensitization potential.
Sustainability
As a synthetic material, 2-Hexylidenehexanal reduces pressure on natural resources. Production typically uses petrochemical feedstocks, though bio-based routes are being explored. The molecule’s efficiency at low doses contributes to reduced environmental load compared to some natural alternatives.
Explore 2-Hexylidenehexanal
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References
- Bauer et al. (2001). Modern Aldehydes in Perfumery. Perfumer & Flavorist.
- IFRA Standards Library IFRA 49th Amendment
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID20864348
Physical Properties
| Molecular Weight | 182.307 g/mol🔬 EPA CompTox |
| Density | 0.841 g/cm^3📊 OPERA |
| Boiling Point | 240.884 °C📊 OPERA |
| Melting Point | 15.326 °C📊 OPERA |
| Flash Point | 89.809 °C📊 OPERA |
| Refractive Index | 1.444 Dimensionless📊 OPERA |
| Molar Volume | 217.351 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.219 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.219 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.219 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.96 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.077 mmHg📊 OPERA |
| Viscosity | 2.403 cP📊 OPERA |
| Surface Tension | 26.896 dyn/cm📊 OPERA |
| Thermal Conductivity | 138.003 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 | 8 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 57.731 cm^3/mol📊 OPERA |
| Polarizability | 22.886 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.
