2-Nonanone (CAS 821-55-6) — Sweet Middle Note Fragrance Ingredient
2-Nonanone
CAS 821-55-6
What Is 2-Nonanone?
2-Nonanone is a synthetic ketone used in perfumery to add fruity, waxy, and slightly cheesy nuances. It’s found in trace amounts in some dairy products and fermented foods. This molecule matters because it bridges gourmand and floral accords, offering perfumers a versatile tool for creating creamy, lactonic effects without actual dairy ingredients.
Safety Profile
GENERALLY SAFEWhat Does 2-Nonanone Smell Like?
2-Nonanone opens with a paradoxical duality – the waxy sweetness of honeycomb meets the faint tang of aged cheese. As it evolves, the dairy facets recede, revealing a creamy coconut undertone that lingers like suntan lotion on warm skin. In drydown, it leaves a subtle cashew-like nuttiness that blends seamlessly with woody bases.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to create hyperrealistic ‘green milk’ effect in the galbanum accord, adding lactonic depth to the sharp vegetal notes.
2D Molecular Structure
SMILES: CCCCCCCC(C)=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Nonanone is a medium-chain ketone (C9H18O) with a linear carbon skeleton. Industrially produced via oxidation of nonane or through crossed Claisen condensations. The molecular symmetry prevents chirality, making synthesis straightforward. Exhibits typical ketone reactivity but is relatively stable in formulations due to steric hindrance around the carbonyl group.
Physical & Chemical Properties
| Boiling Point | 195-197 °C |
|---|---|
| Density | 0.82 g/cm³ |
| Vapor Pressure | 0.3 mmHg at 25°C |
| LogP | 3.1 |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | For creamy lactonic effects |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Masking agent in household products |
Classic Accords
Tip: Use with ionones to create photorealistic buttered popcorn effects.
Alternatives & Comparisons
For stronger coconut-milk character with less waxy nuance. Preferred in tropical compositions.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted under current IFRA standards.
GHS Classification
RIFM Assessment
RIFM assessment complete – no significant safety concerns at typical usage levels.
Sustainability
Synthesized from petrochemical feedstocks via efficient catalytic processes. No known ecological toxicity issues at fragrance usage levels. Carbon footprint comparable to other synthetic ketones.
Explore 2-Nonanone
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References
- National Center for Biotechnology Information. PubChem Compound Summary for CID 13187, 2-Nonanone. Link
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 821-55-6Physical Properties
| Molecular Weight | 142.24 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.1🔬 PubChem |
| Boiling Point | 192 °C🔬 EPA CompTox |
| Vapor Pressure | 1.6 mmHg @ 25°C📊 OPERA |
| Flash Point | 64.4 °C🔬 EPA CompTox |
| Involatility Index | 0.1446💻 Calculated |
| log Kp (skin permeability) | -1.367💻 Calculated |
| SMILES | CCCCCCCC(=O)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Moderate💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | coconutfattyfruityherbal• leffingwell |
| Functional Groups | ketone💻 RDKit |
| “Its proper odor is not exactly agreeable, and it serves mainly the purpose of increasing the power and diffusion of the fragrance in which it is incorporated.”📖 Arctander | |
| 2-Nonanone has a characteristic rue odor. It has a rose and tea-like flavor.📖 Fenaroli | |
Flavor Notes (Arctander)
| “It finds also some use in flavor compositions, e. g. in imitation Rose and Tea, in fruit complexes or various berry compositions.”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.2273 ppm (n=9)📖 van Gemert |
Regulatory Status
| FEMA Number | FEMA 2785⚖️ FEMA GRAS |
| GRAS Status | Generally Recognized as Safe⚖️ FEMA GRAS |
| 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: DTXSID2022125
Physical Properties
| Molecular Weight | 142.242 g/mol🔬 EPA CompTox |
| Density | 0.826 g/cm^3🔬 EPA CTX |
| Boiling Point | 193.289 °C🔬 EPA CTX |
| Melting Point | -11.62 °C🔬 EPA CTX |
| Flash Point | 67.682 °C🔬 EPA CTX |
| Refractive Index | 1.417 Dimensionless📊 OPERA |
| Molar Volume | 174.216 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.143 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.213 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.213 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.58 Log10 unitless📊 OPERA |
| Water Solubility | 0.002 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.757 mmHg🔬 EPA CTX |
| Viscosity | 1.325 cP📊 OPERA |
| Surface Tension | 26.563 dyn/cm📊 OPERA |
| Thermal Conductivity | 138.4 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 | 43.774 cm^3/mol📊 OPERA |
| Polarizability | 17.353 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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