3-Methyl-2-butenal (CAS 107-86-8) — Green Top Note Fragrance Ingredient
3-Methyl-2-butenal
CAS 107-86-8
What Is 3-Methyl-2-butenal?
3-Methyl-2-butenal is a synthetic fragrance ingredient with a strong, green, leafy aroma. It’s often used in perfumes to add a crisp, fresh quality reminiscent of crushed leaves or unripe fruit. This aldehyde is valued for its ability to enhance natural green notes in fragrances, making it a subtle but important player in many fresh and botanical scents.
Safety Profile
USE WITH AWARENESSWhat Does 3-Methyl-2-butenal Smell Like?
3-Methyl-2-butenal delivers an intense, piercing green character – imagine the sharp snap of breaking a fresh leaf stem combined with the bitter greenness of underripe apples. Its initial burst is almost aggressively vegetal, like tomato vines or crushed galbanum, which then settles into a cleaner, more refined green note. The dry-down reveals a faintly sweet, hay-like quality that lingers subtly on the skin.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to amplify the hyper-realistic galbanum effect in this groundbreaking green chypre, adding razor-sharp leafiness to the top notes.
Contributes to the cold, metallic green iris effect, providing structural crispness to the floral heart.
Enhances the tomato leaf illusion, working with stemone to create a photorealistic garden effect.
2D Molecular Structure
SMILES: CC(C)=CC=O
Chemistry, Properties & Perfumer Guide
The Chemistry
3-Methyl-2-butenal is an α,β-unsaturated aldehyde with the molecular formula C5H8O. As a synthetic material, it’s typically produced through oxidation of 3-methyl-2-buten-1-ol or via aldol condensation reactions. The double bond adjacent to the carbonyl group makes it reactive and particularly potent olfactorily. Its simple structure belies its powerful odor impact, with detection thresholds in the low parts-per-billion range.
Physical & Chemical Properties
| Boiling Point | 137-138 °C |
|---|---|
| Density | 0.855 g/cm³ |
| Refractive Index | 1.428 |
| Flash Point | 32 °C |
| Vapor Pressure | 10.5 mmHg at 25°C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Used sparingly for green top notes |
| Functional Fragrance | 0.05-0.2% | Up to 0.5% | Adds freshness to household products |
| Flavor | 1-5 ppm | Up to 10 ppm | Used for green apple nuances |
Classic Accords
Tip: Stabilize in ethanol before adding to water-based formulations to prevent polymerization.
Alternatives & Comparisons
For a softer, more natural green effect with less intensity and better stability in formulations.
When seeking a more complex, vegetal green note with tomato leaf characteristics.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA standards.
GHS Classification
RIFM Assessment
RIFM evaluation confirms safe use at current industry levels with recommended concentration limits.
Sustainability
As a synthetic material, 3-methyl-2-butenal has minimal environmental impact in production. Its high potency means very small quantities are needed in formulations, reducing overall chemical load. The synthetic route avoids agricultural resource use, though some processes may involve petrochemical feedstocks.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090860
- Arctander, S. (1969). Perfume and Flavor Chemicals. Allured Publishing.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 107-86-8Physical Properties
| Molecular Weight | 84.12 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.2🔬 PubChem |
| Boiling Point | 134 °C🔬 EPA CompTox |
| Vapor Pressure | 5.6 mmHg @ 25°C📊 OPERA |
| Flash Point | 37 °C🔬 EPA CompTox |
| Involatility Index | 0.6581💻 Calculated |
| log Kp (skin permeability) | -2.361💻 Calculated |
| SMILES | CC(=CC=O)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Moderate💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | almondfruitynuttyspicy• leffingwell |
| Functional Groups | aldehydealkene💻 RDKit |
| “Powerful and very diffusive, penetrating "gassy" odor of green-ethereal character. Very poor tenacity.”📖 Arctander | |
| 3-Methyl-2-butenal has an almond odor.📖 Fenaroli | |
Flavor Notes (Arctander)
| “This aldehyde has found use in flavor compositions, mainly in the reconstitution of Raspberry flavor and "true-to-Nature" imitation Raspberry. It is used in trace concentrations only, but lends a powerful lift of freshly pressed juice to the aroma.”📖 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: DTXSID8029606
Physical Properties
| Molecular Weight | 84.118 g/mol🔬 EPA CompTox |
| Density | 0.884 g/cm^3🔬 EPA CTX |
| Boiling Point | 134.55 °C🔬 EPA CTX |
| Melting Point | -20 °C🔬 EPA CTX |
| Flash Point | 37.05 °C🔬 EPA CTX |
| Refractive Index | 1.411 Dimensionless📊 OPERA |
| Molar Volume | 101.804 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 0.53 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 1.045 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.045 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.23 Log10 unitless📊 OPERA |
| Water Solubility | 1.308 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 6.559 mmHg🔬 EPA CTX |
| Viscosity | 0.435 cP📊 OPERA |
| Surface Tension | 23.541 dyn/cm📊 OPERA |
| Thermal Conductivity | 140.055 mW/(m*K)📊 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 | 1 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 25.301 cm^3/mol📊 OPERA |
| Polarizability | 10.03 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.
