4-Heptenal (CAS 6728-31-0) — Green Top Note Fragrance Ingredient
4-Heptenal
CAS 6728-31-0
What Is 4-Heptenal?
4-Heptenal is a synthetic fragrance ingredient with a powerful green, fatty odor reminiscent of crushed leaves and cucumber. It’s found in trace amounts in some perfumes and functional fragrances. This aldehyde contributes a crisp, vegetal freshness that perfumers use to create naturalistic green effects or to modify fruity notes.
Safety Profile
USE WITH AWARENESSWhat Does 4-Heptenal Smell Like?
4-Heptenal bursts with an intensely green, almost aggressive top note – imagine snapping a fresh cucumber stem with bitter chlorophyll undertones. As it evolves, the sharpness mellows into a fatty, marine-like character akin to seaweed drying in the sun. The dry-down reveals a subtle melon-like sweetness lingering beneath persistent vegetal tones. At high concentrations, it can smell like rancid oil, but when expertly diluted, it adds remarkable freshness to floral compositions.
2D Molecular Structure
SMILES: CC\C=C/CCC=O
Chemistry, Properties & Perfumer Guide
The Chemistry
4-Heptenal is an α,β-unsaturated aldehyde with the molecular formula C7H12O. As a synthetic material, it’s typically produced through the oxidation of corresponding alcohols or via aldol condensation reactions. The double bond at the 4-position contributes to its reactivity and distinctive green odor profile. Being an aldehyde, it’s prone to oxidation and requires stabilization in formulations.
Physical & Chemical Properties
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.01-0.1% | Up to 0.5% | Used as green modifier |
| Functional Fragrance | 0.05-0.3% | Up to 1% | For cucumber/melon effects |
Classic Accords
Tip: Always pre-dilute to 1% or below before incorporating into blends due to potency.
Alternatives & Comparisons
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions currently apply to 4-Heptenal.
RIFM Assessment
Not currently evaluated by RIFM.
Sustainability
As a synthetic material, 4-Heptenal production doesn’t rely on natural resources. However, its synthesis typically involves petrochemical feedstocks. The material’s potency means very small quantities are needed, reducing overall environmental impact per kilogram of finished product.
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Physicochemical Properties
DTXSID: DTXSID50884332
Physical Properties
| Molecular Weight | 112.172 g/mol🔬 EPA CompTox |
| Density | 0.849 g/cm^3🔬 EPA CTX |
| Boiling Point | 151.974 °C📊 OPERA |
| Melting Point | -28.937 °C📊 OPERA |
| Flash Point | 46.82 °C📊 OPERA |
| Refractive Index | 1.428 Dimensionless📊 OPERA |
| Molar Volume | 135.016 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.856 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 1.856 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.856 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.96 Log10 unitless📊 OPERA |
| Water Solubility | 0.026 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 1.937 mmHg📊 OPERA |
| Viscosity | 0.991 cP📊 OPERA |
| Surface Tension | 25.4 dyn/cm📊 OPERA |
| Thermal Conductivity | 145.215 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 | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 34.724 cm^3/mol📊 OPERA |
| Polarizability | 13.766 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.
