Allyl alpha-ionone (CAS 79-78-7) — Floral Middle Note Fragrance Ingredient
Allyl alpha-ionone
CAS 79-78-7
What Is Allyl alpha-ionone?
Allyl alpha-ionone is a synthetic fragrance ingredient commonly found in perfumes and personal care products. It contributes to floral and woody scent profiles. This molecule matters because it mimics natural violet-like aromas at a fraction of the cost, making luxury scents more accessible.
Safety Profile
USE WITH AWARENESSWhat Does Allyl alpha-ionone Smell Like?
Allyl alpha-ionone opens with a burst of violet petals dusted with powdery orris, evolving into a heart of raspberry jam sweetness with subtle woody undertones. The dry-down reveals a smooth, velvety texture reminiscent of antique cedar chests lined with dried rose petals. Unlike its alpha-ionone parent, the allyl group adds a sharper, more diffusive quality that lingers as a transparent floral haze.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a violet-orris enhancer that bridges the green galbanum top to the powdery iris heart, adding diffusion without sweetness.
Provides the transparent violet-water effect that floats above the heliotropin-anisic base, creating the ‘rain on stone’ illusion.
2D Molecular Structure
SMILES: CC1=CCCC(C)(C)C1C=CC(=O)CCC=C
Chemistry, Properties & Perfumer Guide
The Chemistry
Allyl alpha-ionone belongs to the ionone class of terpenoid ketones, structurally related to beta-ionone found in violets. Synthesized via aldol condensation of citral with acetone followed by allylation, this chiral molecule exists as stereoisomers with differing odor thresholds. The allyl group increases volatility compared to methyl ionones while maintaining the characteristic violet-woody odor profile.
Physical & Chemical Properties
| Boiling Point | ~300 °C (estimated) |
|---|---|
| Density | ~0.93 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Violet-woody accent |
| Soap | 0.1-0.5% | Up to 1% | Stabilizes floral notes |
Classic Accords
Tip: Use with ionones and rosy materials to create dimensional violet effects without excessive powderiness.
Alternatives & Comparisons
For more natural orris effects when cost allows, though less diffusive.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under IFRA 51st Amendment. General ionone limits apply.
GHS Classification
RIFM Assessment
RIFM evaluation confirms safe use at current industry levels with margin of exposure.
Sustainability
Synthetic production avoids agricultural land use and seasonal variability of natural violet extracts. Petroleum-derived precursors are offset by high odor potency requiring minimal quantities per formulation.
Explore Allyl alpha-ionone
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References
- Bauer et al. (2001). Ionones and Damascones in Perfumery. Perfumer & Flavorist.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID4047591
Physical Properties
| Molecular Weight | 232.367 g/mol🔬 EPA CompTox |
| Density | 0.931 g/cm^3🔬 EPA CTX |
| Boiling Point | 300.613 °C📊 OPERA |
| Melting Point | 38.002 °C📊 OPERA |
| Flash Point | 128.327 °C📊 OPERA |
| Refractive Index | 1.514 Dimensionless📊 OPERA |
| Molar Volume | 250.272 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.795 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.795 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.795 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.44 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.002 mmHg📊 OPERA |
| Surface Tension | 32.385 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 | 5 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 75.332 cm^3/mol📊 OPERA |
| Polarizability | 29.864 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.
