2-Cyclohexylpropanal (CAS 2109-22-0) — Green Top to Mid Note Fragrance Ingredient
2-Cyclohexylpropanal
CAS 2109-22-0
What Is 2-Cyclohexylpropanal?
2-Cyclohexylpropanal is a synthetic fragrance ingredient used to add fresh, green, and slightly floral nuances to perfumes. You’ll encounter it in modern floral and citrus fragrances, often lending a crisp, clean character. This aldehyde is prized for its ability to bridge top and heart notes, providing longevity while maintaining brightness. Its subtle complexity makes it valuable for creating sophisticated scent profiles that evolve beautifully on skin.
Safety Profile
GENERALLY SAFEWhat Does 2-Cyclohexylpropanal Smell Like?
2-Cyclohexylpropanal opens with a burst of crisp green freshness, like crushed stems after rain, quickly revealing a delicate floralcy reminiscent of lily petals floating in a citrus-infused spring stream. The heart develops a subtle waxy character akin to freshly peeled cucumber skin, while the dry-down leaves a whisper of clean muskiness—like sun-warmed linen drying in an alpine meadow. Its moderate persistence allows it to serve as both a top note enhancer and heart note anchor, bridging citrus and floral elements with remarkable versatility.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the violet leaf accord, adding a dewy green freshness that contrasts beautifully with the woody base. Its aliphatic character helps unify citrus and floral elements.
Provides a crisp green counterpoint to the white flowers, creating the illusion of stems freshly cut from the bouquet. Its subtle floralcy enhances the naturalistic effect.
2D Molecular Structure
SMILES: CC(C=O)C1CCCCC1
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Cyclohexylpropanal belongs to the aliphatic aldehydes class, characterized by its cyclohexyl group attached to a propanal chain. Synthesized through hydroformylation of cyclohexylpropene or oxidation of the corresponding alcohol, this molecule lacks chirality but displays conformational flexibility that contributes to its odor profile. The aldehyde functional group makes it reactive in perfumery applications, often forming Schiff bases with amines to create novel odorants. Its moderate chain length gives it balanced volatility between traditional C8-C12 aldehydes.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Estimated 210-220°C |
| Density | Approx. 0.89 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Adds green-floral freshness |
| Functional Products | 0.1-0.5% | Up to 1% | For clean, fresh effects |
Classic Accords
Tip: Stabilize in ethanol before adding to water-based formulations to prevent aldehyde degradation.
Alternatives & Comparisons
For stronger green marine effects with similar floralcy but greater diffusion.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted under IFRA standards. Listed on IFRA Transparency List Amendment 49.
RIFM Assessment
RIFM evaluation ongoing; preliminary data suggests low sensitization potential at typical use levels.
Sustainability
As a synthetic material, 2-Cyclohexylpropanal avoids agricultural resource use. Modern production methods employ green chemistry principles with high atom economy. Being petroleum-derived, its carbon footprint depends on production facility energy sources, but typical synthesis routes have lower environmental impact than many natural ingredient extractions.
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References
- IFRA Transparency List Amendment 49 IFRA Official
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 2109-22-0Physical Properties
| Molecular Weight | 140.22 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3🔬 PubChem |
| Boiling Point | 191 °C🔬 EPA CompTox |
| Vapor Pressure | 0.4169 mmHg @ 25°C📊 OPERA |
| Flash Point | 71.4 °C🔬 EPA CompTox |
| Involatility Index | 0.0379💻 Calculated |
| log Kp (skin permeability) | -1.425💻 Calculated |
| SMILES | CC(C=O)C1CCCCC1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.6 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | floralgreen• leffingwell |
| Functional Groups | aldehyde💻 RDKit |
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: DTXSID10862833
Physical Properties
| Molecular Weight | 140.226 g/mol🔬 EPA CompTox |
| Density | 0.897 g/cm^3📊 OPERA |
| Boiling Point | 193.773 °C📊 OPERA |
| Melting Point | 9.842 °C📊 OPERA |
| Flash Point | 69.25 °C📊 OPERA |
| Refractive Index | 1.448 Dimensionless📊 OPERA |
| Molar Volume | 155.882 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.052 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.052 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.052 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.44 Log10 unitless📊 OPERA |
| Water Solubility | 0.006 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.341 mmHg📊 OPERA |
| Viscosity | 3.021 cP📊 OPERA |
| Surface Tension | 30.299 dyn/cm📊 OPERA |
| Thermal Conductivity | 130.94 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 | 2 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 41.722 cm^3/mol📊 OPERA |
| Polarizability | 16.54 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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