Ethyl trans-2-hexenoate (CAS 27829-72-7) — Green Top Note Fragrance Ingredient
Ethyl trans-2-hexenoate
CAS 27829-72-7
What Is Ethyl trans-2-hexenoate?
Ethyl trans-2-hexenoate is a synthetic fragrance ingredient commonly found in fruity and floral perfumes. It contributes a fresh, green apple-like scent with tropical nuances. This ester is valued for its ability to add naturalistic fruit accents without being overly sweet, making it versatile in modern perfumery.
Safety Profile
GENERALLY SAFEWhat Does Ethyl trans-2-hexenoate Smell Like?
Ethyl trans-2-hexenoate bursts with a crisp, unripe apple peel character – tart and slightly waxy with a green stemminess. As it evolves, the scent softens into a juicy pear-like sweetness with subtle floral undertones reminiscent of pineapple skin. The dry-down reveals a clean, slightly woody muskiness that prevents cloying sweetness. Its trans configuration gives sharper green tones compared to the creamier cis isomer.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used for its green apple freshness in this vegetal chypre, contrasting with tomato leaf absolutes to create a garden after rain effect.
Provides tart top notes that mimic unripe mango skin, blending with grapefruit to achieve the fragrance’s signature ‘green riverbank’ accord.
2D Molecular Structure
SMILES: CCC\C=C\C(=O)OCC
Chemistry, Properties & Perfumer Guide
The Chemistry
Ethyl trans-2-hexenoate is an unsaturated ester formed via esterification of trans-2-hexenoic acid with ethanol. The trans configuration at the double bond creates a sharper, greener odor profile compared to the cis isomer. Industrial synthesis typically involves Heck coupling or selective hydrogenation routes. As a β,γ-unsaturated ester, it’s more stable to hydrolysis than α,β-unsaturated counterparts.
Physical & Chemical Properties
| Boiling Point | 198 °C (estimated) |
|---|---|
| Density | 0.89 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Fresh top note accent |
| Functional Fragrances | 0.1-0.5% | Up to 1% | Green apple shampoo notes |
Classic Accords
Tip: Stabilize in ethanol-heavy bases to prevent ester hydrolysis over time.
Alternatives & Comparisons
Softer, more floral character for formulations requiring less green sharpness.
More straightforward apple note without green nuances, better for candy-like fragrances.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions – Class 1 (unrestricted) under Amendment 49.
RIFM Assessment
RIFM assessment confirms safe use at current industry levels.
Sustainability
Synthesized from petrochemical feedstocks but requires minimal energy input compared to complex natural isolates. No known ecological toxicity at production scales. Potential for bio-based production via fermentation routes being explored.
Explore Ethyl trans-2-hexenoate
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References
- Bauer et al. (2001). Common Fragrance and Flavor Materials. Wiley-VCH.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID30885403
Physical Properties
| Molecular Weight | 142.198 g/mol🔬 EPA CompTox |
| Density | 0.916 g/cm^3📊 OPERA |
| Boiling Point | 174.331 °C📊 OPERA |
| Melting Point | -31.211 °C📊 OPERA |
| Flash Point | 62.375 °C🔬 EPA CTX |
| Refractive Index | 1.433 Dimensionless📊 OPERA |
| Molar Volume | 157.686 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.485 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.485 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.485 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.5 Log10 unitless📊 OPERA |
| Water Solubility | 0.03 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 1.2 mmHg📊 OPERA |
| Surface Tension | 27.275 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 26.3 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 40.944 cm^3/mol📊 OPERA |
| Polarizability | 16.232 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.
