Ethyl 3,5,5-trimethylhexanoate (CAS 67707-75-9) — Green Top to Mid Note Fragrance Ingredient
Ethyl 3,5,5-trimethylhexanoate
CAS 67707-75-9
What Is Ethyl 3,5,5-trimethylhexanoate?
Ethyl 3,5,5-trimethylhexanoate is a synthetic fragrance ingredient used to add fruity, green, and slightly woody nuances to perfumes. You’ll encounter it in body sprays, fabric conditioners, and fine fragrances. This ester matters because it provides exceptional stability and versatility, often serving as a bridge between citrus top notes and floral heart accords.
Safety Profile
GENERALLY SAFEWhat Does Ethyl 3,5,5-trimethylhexanoate Smell Like?
A crisp, modern ester with a multifaceted personality. Opens with a burst of green apple peel and underripe pear, transitioning to a dewy floralcy reminiscent of lily-of-the-valley stems. The dry-down reveals a subtle woody backbone that prevents excessive sweetness. Like biting into a tart Granny Smith apple while walking through a just-mowed lawn at dawn.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Provides the crisp, refreshing top note that mimics freshly brewed green tea leaves.
Used to enhance the citrusy freshness while adding a subtle green dimension.
2D Molecular Structure
SMILES: CCOC(=O)CC(C)CC(C)(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Ethyl 3,5,5-trimethylhexanoate belongs to the ester class, synthesized via esterification of 3,5,5-trimethylhexanoic acid with ethanol. Its branched carbon chain contributes to excellent stability against hydrolysis compared to linear chain esters. The three methyl groups create steric hindrance that slows degradation, making it particularly useful in alkaline formulations like soaps and detergents.
Physical & Chemical Properties
| Boiling Point | 198 °C |
|---|---|
| Density | 0.865 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | Fresh top note component |
| Functional Products | 0.1-0.5% | Up to 1% | Provides freshness in detergents |
Classic Accords
Tip: Use with citrus oils to prevent excessive sharpness in the top note.
Alternatives & Comparisons
For a more pronounced fruity character with apple-like qualities.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted under current IFRA standards.
RIFM Assessment
RIFM has reviewed this material and found no significant safety concerns at reported usage levels.
Sustainability
As a synthetic material, production can be optimized for minimal waste. The starting materials are petrochemical derivatives, but modern manufacturing processes achieve high atom economy. Biocatalytic production routes are being explored to improve sustainability.
Explore Ethyl 3,5,5-trimethylhexanoate
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References
- PubChem Compound Summary for Ethyl 3,5,5-trimethylhexanoate PubChem CID
- IFRA Standards Library IFRA
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID7052367
Physical Properties
| Molecular Weight | 186.295 g/mol🔬 EPA CompTox |
| Density | 0.86 g/cm^3🔬 EPA CTX |
| Boiling Point | 204.3 °C🔬 EPA CTX |
| Melting Point | -43.244 °C📊 OPERA |
| Flash Point | 72 °C🔬 EPA CTX |
| Refractive Index | 1.425 Dimensionless📊 OPERA |
| Molar Volume | 214.017 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.59 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.803 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.803 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.01 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.514 mmHg🔬 EPA CTX |
| Viscosity | 1.629 cP📊 OPERA |
| Surface Tension | 26.009 dyn/cm📊 OPERA |
| Thermal Conductivity | 126.618 mW/(m*K)📊 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 | 54.71 cm^3/mol📊 OPERA |
| Polarizability | 21.689 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.
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