.beta.-Irone (CAS 79-70-9) — Floral Heart to base Note Fragrance Ingredient
.beta.-Irone
CAS 79-70-9
What Is .beta.-Irone?
β-Irone is a synthetic fragrance molecule prized for its elegant violet-like aroma. While not found in nature, it’s carefully engineered to replicate the scent of orris root and violets. This ingredient elevates floral perfumes with its sophisticated character, often appearing in high-end fragrances where natural violet extracts would be too costly or inconsistent.
Safety Profile
GENERALLY SAFEWhat Does .beta.-Irone Smell Like?
β-Irone unfolds with an initial burst of powdery violet petals dusted with icing sugar, evolving into a heart of moist rootiness reminiscent of freshly dug orris rhizomes. The dry-down reveals a delicate woody-amber undertone that lingers like the memory of a vintage lipstick. Its character balances between floral sweetness and earthy sophistication, with a cooling metallic edge that distinguishes it from simpler violet compounds.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
β-Irone recreates the melancholic violet-iris accord that defines this classic, providing the powdery floralcy that evaporates like morning dew.
Used alongside natural orris to extend the cold, metallic facets of iris root while maintaining perfumery viability.
2D Molecular Structure
SMILES: CC1CCC(C)=C(\C=C\C(C)=O)C1(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
β-Irone belongs to the ionone class of compounds, specifically a trimethylcyclohexenyl derivative. While not occurring naturally, it’s synthesized through acid-catalyzed cyclization of pseudoionone. The beta isomer exhibits greater olfactory potency than its alpha counterpart. Chirality significantly impacts its scent profile, with different enantiomers displaying varying degrees of floral character.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Approx. 280 °C (estimated) |
| Density | 0.93-0.95 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Violet-iris reconstructions |
| Soap | 0.1-0.5% | Up to 1% | Stabilized in alkaline media |
Classic Accords
Tip: Combine with ionone alpha for a fuller violet effect while controlling costs.
Alternatives & Comparisons
Offers similar violet character with greater diffusion, though less rooty depth.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under IFRA standards. General usage guidelines apply.
RIFM Assessment
Evaluated as safe under current use conditions by RIFM.
Sustainability
As a synthetic material, β-Irone avoids the ecological impact of orris root cultivation which requires 3-5 years of growth before harvest. Its production allows consistent quality without seasonal variation, though energy-intensive synthesis requires responsible manufacturing practices.
Explore .beta.-Irone
Browse essential oils and aroma compounds.
Browse on iHerb →Affiliate disclosure: we may earn a small commission at no extra cost to you.
References
- Arctander, S. (1969). Perfume and Flavor Chemicals. Montclair: Steffen Arctander.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 79-70-9Physical Properties
| Molecular Weight | 206.32 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.2🔬 PubChem |
| Boiling Point | 272 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0692 mmHg @ 25°C📊 OPERA |
| Flash Point | 127.1 °C🔬 EPA CompTox |
| Involatility Index | 0.0052💻 Calculated |
| log Kp (skin permeability) | -1.687💻 Calculated |
| SMILES | CC1CCC(=C(C1(C)C)C=CC(=O)C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 2.3 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | berryfruityvioletwoody• leffingwell |
| Functional Groups | ketonealkene💻 RDKit |
| “sembles beta-Ionone in odor except that the Irone is somewhat more powerful.”📖 Arctander | |
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.
Physicochemical Properties
DTXSID: DTXSID70861640
Physical Properties
| Molecular Weight | 206.329 g/mol🔬 EPA CompTox |
| Density | 0.917 g/cm^3📊 OPERA |
| Boiling Point | 278.427 °C📊 OPERA |
| Melting Point | 32.187 °C📊 OPERA |
| Flash Point | 116.441 °C📊 OPERA |
| Refractive Index | 1.506 Dimensionless📊 OPERA |
| Molar Volume | 223.643 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.187 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.187 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.187 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.9 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.026 mmHg📊 OPERA |
| Surface Tension | 31.26 dyn/cm📊 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 | 2 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 66.412 cm^3/mol📊 OPERA |
| Polarizability | 26.328 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.
Related Research
- 2-Methyl-2-pentenal (CAS 623-36-9) — Green Top Note Fragrance Ingredient
- 4,5,6,7,8,9,10,11,12,13-Decahydrocyclododecaoxazole (CAS 38303-23-0) — Citrus Unknown Note Fragrance Ingredient
- Decahydro-beta-naphthyl acetate (CAS 10519-11-6) — Woody Base Note Fragrance Ingredient
- C11-15-Isoalkanes (CAS 90622-58-5) — Citrus None Note Fragrance Ingredient
