2-Nonenal (CAS 2463-53-8) — Green Middle to base Note Fragrance Ingredient
2-Nonenal
CAS 2463-53-8
What Is 2-Nonenal?
2-Nonenal is a synthetic aroma chemical that creates a distinctive ‘old book’ or cardboard-like smell. People encounter it in trace amounts in aged paper products, some perfumes, and as an off-note in oxidized foods. This molecule matters because it’s a key marker of oxidation and aging, used intentionally in fragrances to create nostalgic or vintage effects, though it must be carefully controlled due to its potent aroma.
Safety Profile
USE WITH AWARENESSWhat Does 2-Nonenal Smell Like?
2-Nonenal delivers an intensely waxy, cardboard-like aroma with fatty undertones reminiscent of old books or stale potato chips. At full strength, it’s unpleasantly rancid, but when diluted, it adds fascinating oxidized nuances. The scent evolves from an initial sharp, almost metallic top note to a persistent waxy-dry heart that lingers for hours. In dry-down, it leaves traces of cucumber-like freshness mixed with papery dryness, making it unexpectedly useful for creating ‘aged paper’ accords or adding complexity to green fragrances.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
This niche fragrance captures the scent of old books, using 2-nonenal to recreate the distinctive oxidized paper aroma alongside woody and musky notes for authenticity.
2D Molecular Structure
SMILES: CCCCCCC=CC=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Nonenal is an unsaturated aldehyde with the molecular formula C9H16O. As an alpha,beta-unsaturated carbonyl compound, it’s highly reactive and prone to oxidation. Industrially produced via aldol condensation of heptanal with acetaldehyde, its synthesis requires careful control to avoid polymerization. The (E)-isomer dominates commercial samples, displaying greater odor potency than the (Z)-form. Its structure makes it a key marker for lipid oxidation in both food chemistry and material degradation studies.
Physical & Chemical Properties
| Boiling Point | 185-187 °C |
|---|---|
| Flash Point | 72 °C |
| Density | 0.84 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.01-0.1% | Up to 0.5% | Used sparingly for vintage effects |
| Functional Fragrance | 0.001-0.01% | Up to 0.05% | Masking agent for oxidation notes |
Classic Accords
Tip: Always pre-dilute to 1% or lower before incorporating due to extreme potency.
Alternatives & Comparisons
The saturated version with similar waxy character but less oxidation notes, useful when a softer effect is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under current IFRA standards (as of 50th Amendment).
GHS Classification
RIFM Assessment
RIFM assessment confirms safe use at current industry levels with no sensitization concerns.
Sustainability
As a synthetic material, 2-nonenal production has minimal environmental impact when manufactured responsibly. Its extreme potency means very small quantities are needed, reducing overall chemical usage. Some manufacturers are exploring bio-based routes using sustainable heptanal feedstocks.
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References
- Sell C. (2006). The Chemistry of Fragrances. RSC Publishing. ISBN 9780854048243
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 2463-53-8Physical Properties
| Molecular Weight | 140.22 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.1🔬 PubChem |
| Boiling Point | 189 °C🔬 EPA CompTox |
| Vapor Pressure | 0.3802 mmHg @ 25°C📊 OPERA |
| Flash Point | 84.4 °C🔬 EPA CompTox |
| Involatility Index | 0.0346💻 Calculated |
| log Kp (skin permeability) | -1.354💻 Calculated |
| SMILES | CCCCCCC=CC=O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.7 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | cucumberfattymelonorriswaxy• leffingwell |
| Functional Groups | aldehydealkene💻 RDKit |
| “It is interesting to note that a chemical called Nonenyl nitrile has a very similar odor, and was developed in the search for a material of said odor and with better stability in air and mild alkali. However, the subject aldehyde seems to perform quite well in soap, presumably because of the extreme dilution which physically protects the aldehyde to a certain degree.”📖 Arctander | |
| 2-Nonenal has a very powerful, penetrating, fatty odor in concentrated form. The odor is orris-like, waxy and quite pleasant on dilution. The odor is also reported as reminiscent of dried orange peels.📖 Fenaroli | |
Sensory Thresholds
| Odor Detection Threshold | 0.0039 ppm (n=2)📖 van Gemert |
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: DTXSID3047219
Physical Properties
| Molecular Weight | 140.226 g/mol🔬 EPA CompTox |
| Density | 0.86 g/cm^3🔬 EPA CTX |
| Boiling Point | 189 °C🔬 EPA CTX |
| Melting Point | -6.925 °C📊 OPERA |
| Flash Point | 84.475 °C🔬 EPA CTX |
| Refractive Index | 1.437 Dimensionless📊 OPERA |
| Molar Volume | 168.029 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.127 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.127 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.127 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.45 Log10 unitless📊 OPERA |
| Water Solubility | 0.004 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.37 mmHg📊 OPERA |
| Viscosity | 1.303 cP📊 OPERA |
| Surface Tension | 27.938 dyn/cm📊 OPERA |
| Thermal Conductivity | 145.804 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 | 43.989 cm^3/mol📊 OPERA |
| Polarizability | 17.439 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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