2-Methyloctanal (CAS 7786-29-0) — Green Top to mid Note Fragrance Ingredient
2-Methyloctanal
CAS 7786-29-0
What Is 2-Methyloctanal?
2-Methyloctanal is a synthetic fragrance ingredient with a powerful, waxy-green odor reminiscent of cucumber peels and fresh leaves. You’ll encounter it in modern perfumes, especially those aiming for crisp, watery, or vegetal effects. This aldehyde matters because it adds a cutting-edge freshness to fragrances, bridging the gap between natural green notes and futuristic synthetics. It’s particularly valued for creating contemporary aquatic and ozonic accords that smell clean without being soapy.
Safety Profile
USE WITH AWARENESSWhat Does 2-Methyloctanal Smell Like?
2-Methyloctanal bursts with an intense, almost metallic greenness – imagine crushing fresh galbanum stems between your fingers, then dipping them in icy water. The top note has a razor-sharp cucumber rind character that evolves into waxy aldehydic tones, like peeling a just-ripe honeydew melon. As it dries down, it reveals a surprisingly soft underbelly of clean linen and dew-drenched leaves. The dryout maintains a persistent green freshness, though the edges round off considerably, leaving a whisper of wet stones and greenhouse humidity.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the dewy violet leaf accord, adding a crisp, almost electric greenness that makes the floral heart feel freshly cut. The aldehyde’s waxy facets help bridge to the woody base.
Provides the startling ‘rain on hot pavement’ effect, with its wet vegetal character enhancing the ginger and cardamom. The molecule’s cooling properties evoke monsoonal humidity.
2D Molecular Structure
SMILES: CCCCCCC(C)C=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Methyloctanal belongs to the branched-chain aldehyde family, characterized by a carbonyl group at the terminal position with a methyl group at the α-carbon. While not found in nature, its structure mimics certain fatty acid degradation products. Industrially synthesized via hydroformylation of 2-methyl-1-heptene, this process yields a racemic mixture. The molecule’s potency stems from its compact structure – the branching increases volatility while the aldehyde group provides strong receptor binding. Unlike straight-chain aldehydes, the methyl group creates steric hindrance that modifies odor characteristics.
Physical & Chemical Properties
| Boiling Point | ~180-185 °C (estimated) |
|---|---|
| Density | ~0.82 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Powerful modifier for green accords |
| Functional Fragrance | 0.01-0.1% | Up to 0.2% | Adds freshness to detergents |
Classic Accords
Tip: Use citronellol or phenyl ethyl alcohol to tame the sharp edges in floral compositions.
Alternatives & Comparisons
Straight-chain aldehyde with similar power but more waxy-rosy character. Better for floral bouquets when you want less vegetal harshness.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions. Listed as safe at current industry usage levels (IFRA 49th Amendment).
EU Allergen Declaration
Not listed as EU allergen. Does not require declaration under Regulation (EC) No 1223/2009.
GHS Classification
RIFM Assessment
RIFM evaluation confirms safe use at reported concentrations. No evidence of phototoxicity or significant sensitization at standard levels.
Sustainability
As a synthetic material, 2-methyloctanal has minimal environmental impact in production. The hydroformylation process uses platinum catalysts that are typically recovered and recycled. Being highly potent, it requires minimal quantities per formulation, reducing overall carbon footprint compared to natural alternatives like violet leaf absolute.
Explore 2-Methyloctanal
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090869
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 7786-29-0Physical Properties
| Molecular Weight | 142.24 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.3🔬 PubChem |
| Boiling Point | 82 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.225💻 Calculated |
| SMILES | CCCCCCC(C)C=O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
Odor & Flavor
| Primary Descriptors | citrusfattyfloralorangerose• leffingwell |
| Functional Groups | aldehyde💻 RDKit |
| “Delicately floral, fresh-"aldehydic" odor, much less fatty than Nonanal, more rosy, Lily-like. Moderate tenacity.”📖 Arctander | |
| 2-Methyloctanal has a delicate, floral odor, rose- or lily-like.📖 Fenaroli | |
Flavor Notes (Arctander)
| “It finds some use in flavor compositions, mainly in Citrus types where it may partly or wholly substitute the conventional Nonanal. Concentration used is about 1 to 2 ppm in the finished product.”📖 Arctander |
Regulatory Status
| FEMA Number | FEMA 2727⚖️ FEMA GRAS |
| GRAS Status | Generally Recognized as Safe⚖️ FEMA GRAS |
| IOFI Classification | Artificial📖 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: DTXSID2052528
Physical Properties
| Molecular Weight | 142.242 g/mol🔬 EPA CompTox |
| Density | 0.821 g/cm^3📊 OPERA |
| Boiling Point | 187.825 °C📊 OPERA |
| Melting Point | -5.01 °C📊 OPERA |
| Flash Point | 60.483 °C📊 OPERA |
| Refractive Index | 1.416 Dimensionless📊 OPERA |
| Molar Volume | 174.791 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.357 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.357 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.357 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.31 Log10 unitless📊 OPERA |
| Water Solubility | 0.002 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.591 mmHg📊 OPERA |
| Viscosity | 1.388 cP📊 OPERA |
| Surface Tension | 25.622 dyn/cm📊 OPERA |
| Thermal Conductivity | 137.629 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 | 6 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 43.89 cm^3/mol📊 OPERA |
| Polarizability | 17.399 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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