Acetaldehyde, diphenethyl acetal (CAS 122-71-4) — Floral Top to middle Note Fragrance Ingredient
Acetaldehyde, diphenethyl acetal
CAS 122-71-4
What Is Acetaldehyde, diphenethyl acetal?
Acetaldehyde, diphenethyl acetal is a synthetic fragrance ingredient used to add green, floral, and slightly fruity nuances to perfumes. It’s found in various fine fragrances and personal care products. This molecule matters because it contributes to fresh, natural-smelling accords despite being lab-created, allowing perfumers to achieve consistent effects without relying on natural extracts.
Safety Profile
USE WITH AWARENESSWhat Does Acetaldehyde, diphenethyl acetal Smell Like?
Opens with a crisp green apple peel sharpness that quickly softens into a dewy floral heart reminiscent of lily-of-the-valley with a waxy undertone. The dry-down reveals a subtle honeyed sweetness balanced by clean aldehydic freshness. Acts as a chameleon – in citrus blends it reads as juicy, in florals it adds luminosity, and in woody compositions it provides an airy lift. The overall effect is like morning dew on spring blossoms with a faint metallic edge that keeps the scent vibrant.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the hyper-realistic green galbanum opening, creating an effect of crushed stems and leaves. The acetal’s sharpness cuts through the dense base to maintain freshness.
Provides the sparkling citrus-floral transition note that bridges lemon top to woody base. Its watercolor-like quality prevents the composition from becoming too heavy.
2D Molecular Structure
SMILES: CC(OCCC1=CC=CC=C1)OCCC1=CC=CC=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
Acetaldehyde, diphenethyl acetal belongs to the acetal class of organic compounds, formed by the reaction of acetaldehyde with phenethyl alcohol. These acetals are prized in perfumery for their stability compared to parent aldehydes. Industrial synthesis typically involves acid-catalyzed condensation under controlled conditions. The molecule lacks chirality but exhibits conformational flexibility that contributes to its nuanced scent profile.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | ~250 °C (estimated) |
| Density | ~1.0 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Fresh floral modifier |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Clean scent enhancer |
Classic Accords
Tip: Use to ‘wet down’ dry green materials and prevent harshness in modern chypres.
Alternatives & Comparisons
When more ozone-like freshness is needed without the green facets. Provides similar diffusion but with a cleaner laundry character.
For simpler rose-honey effects when the acetal’s complexity isn’t required. Lacks the green top notes but shares the floral heart.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted under IFRA standards. Approved for use in all categories.
RIFM Assessment
Evaluated by RIFM in 2018 with no significant safety concerns at current usage levels.
Sustainability
As a synthetic material, production avoids agricultural land use but depends on petrochemical feedstocks. Manufacturing typically employs green chemistry principles with high atom economy. No known ecological toxicity concerns at production scale.
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References
- Arctander, S. (1969). Perfume and Flavor Chemicals. Montclair, NJ.
- IFRA Standards Library (2023). 49th Amendment. IFRA Standards
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 122-71-4Physical Properties
| Molecular Weight | 270.4 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 4.4🔬 PubChem |
| Boiling Point | 370 °C🔬 EPA CompTox |
| Vapor Pressure | 0 mmHg @ 25°C📊 OPERA |
| Flash Point | 125 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.225💻 Calculated |
| SMILES | CC(OCCC1=CC=CC=C1)OCCC2=CC=CC=C2🔬 PubChem |
Volatility & Performance
| Fragrance Note | Base💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 11.9 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | balsamicfloralleafyrosewarm• leffingwell |
| Functional Groups | etheraromatic💻 RDKit |
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: DTXSID8051625
Physical Properties
| Molecular Weight | 270.372 g/mol🔬 EPA CompTox |
| Density | 1.03 g/cm^3📊 OPERA |
| Boiling Point | 362.895 °C📊 OPERA |
| Melting Point | 74.942 °C📊 OPERA |
| Flash Point | 143.882 °C📊 OPERA |
| Refractive Index | 1.54 Dimensionless📊 OPERA |
| Molar Volume | 262.081 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.193 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.193 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.193 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 8.53 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0 mmHg📊 OPERA |
| Viscosity | 14.473 cP📊 OPERA |
| Surface Tension | 40.159 dyn/cm📊 OPERA |
| Thermal Conductivity | 140.122 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 | 8 count💻 Computed |
| Aromatic Rings | 2 count💻 Computed |
| Molar Refractivity | 82.27 cm^3/mol📊 OPERA |
| Polarizability | 32.614 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.
