Phenylacetaldehyde dimethyl acetal (CAS 101-48-4) — Floral Top to Middle Note Fragrance Ingredient
Phenylacetaldehyde dimethyl acetal
CAS 101-48-4
What Is Phenylacetaldehyde dimethyl acetal?
Phenylacetaldehyde dimethyl acetal is a synthetic fragrance ingredient that adds a green, floral character to perfumes and scented products. You’ll encounter it in floral bouquets, soaps, and air fresheners. This molecule matters because it provides a stable, long-lasting floral note that doesn’t fade quickly like some natural floral extracts. It’s particularly valued for creating realistic hyacinth and rose accords in fine fragrances.
Safety Profile
GENERALLY SAFEWhat Does Phenylacetaldehyde dimethyl acetal Smell Like?
Phenylacetaldehyde dimethyl acetal opens with a crisp, green hyacinth burst – imagine crushed stems and dewy petals. The heart reveals a delicate floralcy, like rose petals dipped in honey, with a subtle waxy undertone. As it dries, it maintains a clean, soapy floral character with faint powdery nuances. The overall effect is of a well-tended spring garden after rain, with remarkable tenacity for a floral note.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to recreate the luminous lily-of-the-valley accord, providing green floralcy that complements the natural extracts. Its stability helps maintain the fragrance’s iconic freshness.
Contributes to the sharp green opening and floral heart, blending with galbanum and iris for that distinctive crisp yet feminine character.
2D Molecular Structure
SMILES: COC(CC1=CC=CC=C1)OC
Chemistry, Properties & Perfumer Guide
The Chemistry
Phenylacetaldehyde dimethyl acetal is an aromatic acetal derived from phenylacetaldehyde. As a synthetic, it’s produced through acid-catalyzed reactions between phenylacetaldehyde and methanol. The acetal group makes it more stable than its aldehyde precursor, resisting oxidation while slowly releasing the parent aldehyde during evaporation. This controlled release mechanism contributes to its lasting floral character in fragrances.
Physical & Chemical Properties
| Boiling Point | ~220 °C |
|---|---|
| Density | ~1.0 g/cm³ |
| Refractive Index | ~1.49 |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | Up to 5% | For floral green accents |
| Soaps/Detergents | 0.5-1% | Up to 2% | Provides stable floralcy |
Classic Accords
Tip: Use with citrus top notes to prevent excessive green sharpness in floral compositions.
Alternatives & Comparisons
The parent aldehyde provides more intense floral character but is less stable and more prone to causing sensitization.
Offers similar floral green effects with slightly more honeyed undertones and better stability in alkaline products.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under current IFRA Standards (as of 2023).
RIFM Assessment
RIFM assessment confirms low sensitization potential at typical use levels.
Sustainability
As a synthetic material, phenylacetaldehyde dimethyl acetal has consistent quality and doesn’t require agricultural land. Production typically uses petrochemical feedstocks, though some manufacturers are exploring bio-based routes. Its efficiency and longevity in formulations contribute to reduced environmental load versus some natural alternatives.
Explore Phenylacetaldehyde dimethyl acetal
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References
- Brenna et al. (2002). Fragrance Chemistry. Tetrahedron. DOI:10.1016/S0040-4020(02)00029-2
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 101-48-4Physical Properties
| Molecular Weight | 166.22 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.1🔬 PubChem |
| Boiling Point | 219 °C🔬 EPA CompTox |
| Vapor Pressure | 1.6801 mmHg @ 25°C📊 OPERA |
| Flash Point | 91 °C🔬 EPA CompTox |
| Involatility Index | 0.1405💻 Calculated |
| log Kp (skin permeability) | -2.223💻 Calculated |
| SMILES | COC(CC1=CC=CC=C1)OC🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Moderate💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | earthyfloralgreen• leffingwell |
| Functional Groups | etheraromatic💻 RDKit |
| Phenylacetaldehyde dimethyl acetal has a strong, green odor with a hyacinthlike note. At low levels, it has a sweet, green, spicy flavor, turning bitter at high levels.📖 Fenaroli | |
Sensory Thresholds
| Odor Detection Threshold | 0.0006 ppm📖 van Gemert |
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: DTXSID3047001
Physical Properties
| Molecular Weight | 166.22 g/mol🔬 EPA CompTox |
| Density | 1.004 g/cm^3🔬 EPA CTX |
| Boiling Point | 219.5 °C🔬 EPA CTX |
| Melting Point | 5.139 °C📊 OPERA |
| Flash Point | 91 °C🔬 EPA CTX |
| Refractive Index | 1.488 Dimensionless📊 OPERA |
| Molar Volume | 168.366 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.23 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 1.924 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.924 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.08 Log10 unitless📊 OPERA |
| Water Solubility | 0.023 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 1.883 mmHg🔬 EPA CTX |
| Viscosity | 2.369 cP📊 OPERA |
| Surface Tension | 32.696 dyn/cm📊 OPERA |
| Thermal Conductivity | 136.878 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 18.46 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 4 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 48.517 cm^3/mol📊 OPERA |
| Polarizability | 19.234 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.
