4-Methyl-2-phenyl-2-pentenal (CAS 26643-91-4) — Woody Heart to Base Note Fragrance Ingredient
4-Methyl-2-phenyl-2-pentenal
CAS 26643-91-4
What Is 4-Methyl-2-phenyl-2-pentenal?
4-Methyl-2-phenyl-2-pentenal is a synthetic fragrance ingredient used in perfumes and personal care products. It contributes a unique, complex character to fragrances. This aldehyde is valued by perfumers for its ability to add depth and sophistication to floral and woody compositions, often serving as a subtle but impactful modifier.
Safety Profile
USE WITH AWARENESSWhat Does 4-Methyl-2-phenyl-2-pentenal Smell Like?
4-Methyl-2-phenyl-2-pentenal presents a rich, complex aroma with a blend of floral, woody, and slightly fruity nuances. The top note has a fresh, green character that evolves into a heart of delicate floralcy with hints of rose and jasmine. The dry-down reveals a warm, woody base with a subtle sweetness. Its behavior on skin is elegant, providing a long-lasting yet non-overpowering presence that enhances the overall fragrance structure.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a subtle modifier to enhance the floral bouquet, adding depth and complexity to the iconic aldehydic structure.
Contributes to the rich floral heart, blending seamlessly with ylang-ylang and rose for a luxurious effect.
Adds a woody-sweet nuance to the fresh citrus top, balancing the composition.
Used in trace amounts to enhance the dark floral and woody accords, adding sophistication.
Modifies the floral explosion, providing a subtle woody undertone to the sweet bouquet.
2D Molecular Structure
SMILES: CC(C)C=C(C=O)C1=CC=CC=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
4-Methyl-2-phenyl-2-pentenal is an unsaturated aldehyde belonging to the phenylpentenal class. It is synthesized through aldol condensation reactions, typically involving benzaldehyde and methyl ethyl ketone derivatives. The molecule features a conjugated double bond system that contributes to its stability and olfactory properties. Its synthetic origin allows for precise control over purity and isomer distribution, making it a reliable ingredient for perfumers.
Physical & Chemical Properties
| Boiling Point | Not available |
|---|---|
| Density | Not available |
| Vapor Pressure | Not available |
| Solubility | Not available |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used as a modifier in floral and woody compositions |
| Personal Care | 0.1-1% | Up to 2% | Adds sophistication to body care products |
| Home Fragrance | 0.2-1.5% | Up to 3% | Enhances woody and floral home scents |
Classic Accords
Tip: Use in trace amounts to enhance floral and woody accords without overpowering the composition.
Alternatives & Comparisons
Offers a more pronounced floral character with green nuances, suitable for stronger floral compositions.
Provides a warmer, spicier alternative with similar molecular structure but different olfactory profile.
A more stable alternative with jasmine-like floralcy and better skin adhesion.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific IFRA restrictions. General aldehyde guidelines apply.
EU Allergen Declaration
Not listed as an EU allergen.
RIFM Assessment
RIFM assessment pending. Limited data available.
Sustainability
As a synthetic ingredient, 4-Methyl-2-phenyl-2-pentenal is produced through controlled chemical processes with minimal environmental impact. Its efficient synthesis reduces the need for natural resource extraction. The manufacturing process can be optimized for energy efficiency and waste reduction, aligning with green chemistry principles.
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References
- PubChem Compound Summary PubChem
- IFRA Standards Library IFRA
- RIFM Fragrance Ingredient Database RIFM
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 26643-91-4Physical Properties
| Molecular Weight | 174.24 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.9🔬 PubChem |
| Boiling Point | 82 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.704💻 Calculated |
| SMILES | CC(C)C=C(C=O)C1=CC=CC=C1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
Odor & Flavor
| Primary Descriptors | floralwoody• leffingwell |
| Functional Groups | aldehydealkenearomatic💻 RDKit |
| 4-Methyl-2-phenyl-2-pentenal has a cocoa aroma. It is often used in chocolate and cocoa-type flavors.📖 Fenaroli | |
Regulatory Status
| IOFI Classification | Nature Identical📖 Fenaroli |
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: DTXSID80865311
Physical Properties
| Molecular Weight | 174.243 g/mol🔬 EPA CompTox |
| Density | 0.983 g/cm^3🔬 EPA CTX |
| Boiling Point | 276.316 °C📊 OPERA |
| Melting Point | 26.334 °C📊 OPERA |
| Flash Point | 114.482 °C📊 OPERA |
| Refractive Index | 1.518 Dimensionless📊 OPERA |
| Molar Volume | 180.982 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.838 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.838 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.838 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.81 Log10 unitless📊 OPERA |
| Water Solubility | 0.002 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.055 mmHg📊 OPERA |
| Viscosity | 2.754 cP📊 OPERA |
| Surface Tension | 33.741 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 | 3 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 54.829 cm^3/mol📊 OPERA |
| Polarizability | 21.736 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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