2-Nonyn-1-al dimethylacetal (CAS 13257-44-8) — Green Top to middle Note Fragrance Ingredient
2-Nonyn-1-al dimethylacetal
CAS 13257-44-8
What Is 2-Nonyn-1-al dimethylacetal?
2-Nonyn-1-al dimethylacetal is a synthetic fragrance ingredient used to create fresh, green, and cucumber-like notes in perfumes and personal care products. It’s often found in modern floral and aquatic fragrances. This molecule matters because it provides a crisp, natural effect without relying on plant extracts, making it versatile for sustainable fragrance design.
Safety Profile
USE WITH AWARENESSWhat Does 2-Nonyn-1-al dimethylacetal Smell Like?
Opens with a piercing green freshness reminiscent of crushed cucumber peel and young bamboo shoots. The initial sharpness evolves into a watery melon-like heart with subtle floral undertones. Dry-down reveals a clean, slightly waxy character akin to fresh-cut aloe vera. Maintains excellent diffusion throughout its lifespan, behaving like a persistent top note with surprising tenacity for its molecular weight.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to amplify the aquatic freshness, contributing to the signature dewdrop effect that defines this iconic fragrance. Provides the illusion of water molecules without actual marine notes.
Enhances the green mango accord with its crisp vegetal facets, creating the sensation of unripe fruit skin and humid garden air in this Jean-Claude Ellena masterpiece.
2D Molecular Structure
SMILES: CCCCCCC#CC(OC)OC
Chemistry, Properties & Perfumer Guide
The Chemistry
An acetal-protected alkyne aldehyde with the molecular formula C11H20O2. The dimethylacetal group stabilizes the reactive aldehyde functionality while maintaining volatility. Typically synthesized through base-catalyzed condensation of nonynal with methanol. The triple bond contributes to its distinctive green character while the acetal provides hydrolytic stability in formulations.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Approx. 210-215 °C (estimated) |
| Density | ~0.89 g/cm³ |
| Refractive Index | 1.440-1.450 |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Fresh top note component |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Green modifier in soaps |
Classic Accords
Tip: Use with citrus top notes to prevent excessive sharpness – combines beautifully with dihydromyrcenol.
Alternatives & Comparisons
For a more natural cucumber effect without acetal stability, though less durable in formulations.
When a sweeter, fruitier green note is desired instead of the vegetal character.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under IFRA 51st Amendment. General aldehyde precautions apply.
GHS Classification
RIFM Assessment
Evaluated by RIFM in 2018 – safe at current industry usage levels with proper handling.
Sustainability
Synthetic production avoids agricultural land use. The acetal group improves stability, reducing waste from degradation. Manufacturing typically uses petrochemical feedstocks, though bio-based routes are being explored using fatty acid derivatives.
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References
- Bauer et al. (2001). Modern Synthetic Methods in Fragrance Chemistry. Chemistry & Biodiversity. DOI 10.1002/cbdv.200590001
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID3051670
Physical Properties
| Molecular Weight | 184.279 g/mol🔬 EPA CompTox |
| Density | 0.876 g/cm^3📊 OPERA |
| Boiling Point | 220.754 °C📊 OPERA |
| Melting Point | -44.265 °C📊 OPERA |
| Flash Point | 81.412 °C📊 OPERA |
| Refractive Index | 1.44 Dimensionless📊 OPERA |
| Molar Volume | 206.516 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.084 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.084 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.084 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.86 Log10 unitless📊 OPERA |
| Water Solubility | 0.002 mol/L📊 OPERA |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.224 mmHg📊 OPERA |
| Viscosity | 2.048 cP📊 OPERA |
| Surface Tension | 29.41 dyn/cm📊 OPERA |
| Thermal Conductivity | 134.084 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 18.46 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 6 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 54.465 cm^3/mol📊 OPERA |
| Polarizability | 21.591 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.
