Octahydrocoumarin (CAS 4430-31-3) — Woody Middle to base Note Fragrance Ingredient
Octahydrocoumarin
CAS 4430-31-3
What Is Octahydrocoumarin?
Octahydrocoumarin is a synthetic fragrance ingredient with a sweet, woody, and slightly herbal aroma. It’s found in perfumes, soaps, and household products where a warm, coumarin-like scent is desired. This versatile molecule bridges gourmand and woody fragrance profiles, often used to add depth without being overly sweet.
Safety Profile
GENERALLY SAFEWhat Does Octahydrocoumarin Smell Like?
Octahydrocoumarin unfolds with an initial burst of sweet hay and vanilla, reminiscent of sun-warmed meadows. As it evolves, the heart reveals a sophisticated woody character – like aged oak barrels storing fine liquor, with subtle herbal undertones of dried chamomile. The dry-down is remarkably persistent, leaving a soft musky-amber trail that blends seamlessly with sandalwood and tonka bean accords. Unlike natural coumarin, it lacks the sharp medicinal edge, offering instead a rounder, more diffusive sweetness that works beautifully in modern oriental and fougère compositions.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a synthetic coumarin alternative in the vanilla-herbal dry down, providing a smooth transition between citrus top notes and animalic base.
Contributes to the leather-woody accord with its sweet-dry character, balancing violet leaf’s sharpness with rounded warmth.
2D Molecular Structure
SMILES: O=C1CCC2CCCCC2O1
Chemistry, Properties & Perfumer Guide
The Chemistry
Octahydrocoumarin belongs to the cyclic ester (lactone) family, structurally related to coumarin but with full hydrogenation of the benzene ring. This saturation makes it more stable to oxidation while reducing phototoxicity concerns. Industrially produced via catalytic hydrogenation of coumarin or through modified Perkin reactions using cyclohexanone derivatives. The lack of conjugated double bonds shifts its UV absorption away from problematic wavelengths, making it safer for leave-on products than natural coumarin.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | ~250 °C (estimated) |
| Density | ~1.05 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | Up to 5% | Builds sweetness in woody-oriental bases |
| Detergents | 0.1-0.5% | Up to 1% | Provides lasting freshness |
Classic Accords
Tip: Use with ionones to create a radiant woody-floral effect without excessive sweetness.
Alternatives & Comparisons
When a sharper, more pronounced coumarin character is needed, though with greater potential for skin sensitization.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted under IFRA standards. Considered a safer alternative to natural coumarin (IFRA Cat. 4).
RIFM Assessment
Under review by RIFM (2023) with preliminary data suggesting low sensitization potential at current usage levels.
Sustainability
As a fully synthetic material, octahydrocoumarin avoids agricultural land use and seasonal variability. Production typically uses petrochemical feedstocks, though emerging routes explore bio-based cyclohexanone. Energy-intensive hydrogenation process offsets its longevity in fragrance performance.
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References
- Bickers et al. (2005). A toxicologic and dermatologic assessment of cyclic acetals when used as fragrance ingredients. PMID 15842339
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID7052105
Physical Properties
| Molecular Weight | 154.209 g/mol🔬 EPA CompTox |
| Density | 1.091 g/cm^3🔬 EPA CTX |
| Boiling Point | 262.2 °C🔬 EPA CTX |
| Melting Point | 58.545 °C📊 OPERA |
| Flash Point | 107.367 °C🔬 EPA CTX |
| Refractive Index | 1.478 Dimensionless📊 OPERA |
| Molar Volume | 145.968 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.96 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 2.197 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.197 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.77 Log10 unitless📊 OPERA |
| Water Solubility | 0.259 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.002 mmHg🔬 EPA CTX |
| Viscosity | 4.18 cP📊 OPERA |
| Surface Tension | 34.148 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 | 0 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 41.294 cm^3/mol📊 OPERA |
| Polarizability | 16.37 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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