5-Methyl-3-heptanone (CAS 541-85-5) — Green Middle Note Fragrance Ingredient
5-Methyl-3-heptanone
CAS 541-85-5
What Is 5-Methyl-3-heptanone?
5-Methyl-3-heptanone is a synthetic fragrance ingredient used in perfumes and functional fragrances. It contributes to fruity, green, and slightly woody scent profiles. You’ll encounter it in air fresheners, fabric softeners, and some citrus-forward perfumes. This ketone matters because it adds naturalistic fruity-green nuances without being overly sweet. It helps bridge citrus top notes with floral heart notes in modern compositions.
Safety Profile
USE WITH AWARENESSWhat Does 5-Methyl-3-heptanone Smell Like?
5-Methyl-3-heptanone opens with a burst of crisp green apple peel and unripe banana, evolving into a juicy pear-like heart with subtle floral undertones. The dry-down reveals a clean woody-musky character reminiscent of freshly cut bamboo stalks. Unlike sweeter fruit ketones, this maintains an appealing tartness throughout its evolution, behaving like nature’s own green apple essence but with better persistence. When diluted, it takes on a rainwater-fresh quality that makes it invaluable for modern aquatic and citrus colognes.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the tomato leaf accord, providing a crisp green-fruity counterpoint to the herbal heart. The ketone’s naturalistic greenness helps bridge the citrus top to basil and oakmoss base.
Provides the illusion of rain-soaked tropical fruits without sweetness. Works with calone to create the ‘wet stone’ effect while maintaining fruity freshness.
2D Molecular Structure
SMILES: CCC(C)CC(=O)CC
Chemistry, Properties & Perfumer Guide
The Chemistry
5-Methyl-3-heptanone is a branched-chain aliphatic ketone synthesized via aldol condensation of methyl ethyl ketone with butyraldehyde, followed by hydrogenation. Its structure features a ketone group at position 3 with a methyl branch at carbon 5, creating chirality that affects odor perception. Industrial production typically yields a racemic mixture, though enantiopure forms show odor differences. The molecule’s moderate polarity and volatility make it useful for heart note compositions, while its branched structure prevents excessive sweetness compared to straight-chain analogs.
Physical & Chemical Properties
| Boiling Point | 160-162 °C |
|---|---|
| Density | 0.82 g/cm³ |
| Refractive Index | 1.412-1.415 |
| Flash Point | 48 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Green-fruity modifier |
| Functional Fragrances | 0.1-0.5% | Up to 1% | Freshness booster |
Classic Accords
Tip: Use with citrus terpenes to prevent excessive greenness in top notes.
Alternatives & Comparisons
More citrusy and less green. Better for tropical fruit effects but lacks the woody dry-down.
Stronger mushroom-metallic aspect. Use when more naturalistic rain effects are desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions under Amendment 49. Recommended maximum 5% in leave-on products.
GHS Classification
RIFM Assessment
RIFM evaluation complete (2019). Safe at current use levels with recommended precautions.
Sustainability
Synthesized from petrochemical feedstocks but requires minimal energy input compared to similar natural isolates. Carbon footprint comparable to most synthetic fragrance ketones. No known ecological toxicity at production volumes.
Explore 5-Methyl-3-heptanone
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References
- Brenna et al. (2002). Structure-Odor Relationships in Aliphatic Ketones. Perfumer & Flavorist.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 541-85-5Physical Properties
| Molecular Weight | 128.21 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.2🔬 PubChem |
| Boiling Point | 157.2 °C🔬 EPA CompTox |
| Vapor Pressure | 2 mmHg @ 25°C📊 OPERA |
| Flash Point | 58.9 °C🔬 EPA CompTox |
| Involatility Index | 0.1904💻 Calculated |
| log Kp (skin permeability) | -1.92💻 Calculated |
| SMILES | CCC(C)CC(=O)CC🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Moderate💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | fruityherbal• leffingwell |
| Functional Groups | ketone💻 RDKit |
Sensory Thresholds
| Odor Detection Threshold | 31 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: DTXSID9047047
Physical Properties
| Molecular Weight | 128.215 g/mol🔬 EPA CompTox |
| Density | 0.82 g/cm^3🔬 EPA CTX |
| Boiling Point | 158.778 °C🔬 EPA CTX |
| Melting Point | -56.747 °C🔬 EPA CTX |
| Flash Point | 49.164 °C🔬 EPA CTX |
| Refractive Index | 1.409 Dimensionless📊 OPERA |
| Molar Volume | 158.086 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.697 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 2.304 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.304 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.95 Log10 unitless📊 OPERA |
| Water Solubility | 0.023 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 2.006 mmHg🔬 EPA CTX |
| Viscosity | 0.812 cP📊 OPERA |
| Surface Tension | 25.152 dyn/cm📊 OPERA |
| Thermal Conductivity | 133.757 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 | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 39.1 cm^3/mol📊 OPERA |
| Polarizability | 15.5 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.
