2-Methylundecanal dimethyl acetal (CAS 68141-17-3) — Citrus Top to middle Note Fragrance Ingredient
2-Methylundecanal dimethyl acetal
CAS 68141-17-3
What Is 2-Methylundecanal dimethyl acetal?
2-Methylundecanal dimethyl acetal is a synthetic fragrance ingredient used to add fresh, aldehydic, and slightly floral nuances to perfumes. You’ll encounter it in fine fragrances, especially those aiming for a clean, sophisticated edge. This molecule matters because it offers perfumers a stable way to incorporate aldehyde-like brightness without the harshness of true aldehydes, making scents more wearable while maintaining complexity.
Safety Profile
GENERALLY SAFEWhat Does 2-Methylundecanal dimethyl acetal Smell Like?
2-Methylundecanal dimethyl acetal unfolds like crisp linen drying in sunlight – initially sharp and aldehydic, with a metallic edge that quickly softens into waxy citrus tones. The heart reveals surprising floralcy, reminiscent of orange blossom petals dipped in paraffin, while the dry-down leaves a whisper of clean musk and fresh-cut stems. Unlike true aldehydes, it maintains a rounded quality throughout evaporation, never becoming screechy. Perfect for modern interpretations of classic aldehydic florals where subtlety is key.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to modernize the iconic aldehyde bouquet, providing luminosity without the vintage soapiness. The acetal bridges citrus top notes to the floral heart with seamless freshness.
Contributes to the ‘your skin but better’ effect with its clean yet intimate dry-down. Works in concert with ambroxan to create the perfume’s signature warmth.
2D Molecular Structure
SMILES: CCCCCCCCCC(C)C(OC)OC
Chemistry, Properties & Perfumer Guide
The Chemistry
As a dimethyl acetal derivative of 2-methylundecanal, this compound belongs to the protected aldehyde class. The acetal formation stabilizes the aldehyde group against oxidation while allowing controlled release of aldehyde character during evaporation. Synthesized via acid-catalyzed reaction of 2-methylundecanal with methanol, the process typically yields a racemic mixture. The molecular architecture features a branched C12 chain with oxygen atoms at positions 1 and 3, creating a compact yet impactful odor profile.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Solubility | Soluble in alcohol, insoluble in water |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Aldehyde modifier |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Clean linen effects |
Classic Accords
Tip: Use to soften harsh aldehyde edges in floral bouquets – start at 0.2% and increase gradually.
Alternatives & Comparisons
For stronger aldehyde punch in classic floral compositions. Less stable but more diffusive.
When seeking similar freshness with more pronounced floralcy and less aldehydic character.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted under current IFRA standards (Amendment 49).
RIFM Assessment
Considered safe as used in current fragrance applications based on RIFM’s 2018 review.
Sustainability
As a synthetic material, production avoids agricultural land use but depends on petrochemical feedstocks. Modern manufacturing processes typically employ green chemistry principles to minimize waste. The compound’s efficiency at low concentrations reduces environmental load compared to less potent ingredients.
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References
- Brenna et al. (2012). Acetals as Fragrance Ingredients. Chemistry & Biodiversity. DOI:10.1002/cbdv.201100293
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 68141-17-3Physical Properties
| Molecular Weight | 230.39 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 5.6🔬 PubChem |
| Boiling Point | 252 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0107 mmHg @ 25°C📊 OPERA |
| Flash Point | 66.4 °C🔬 EPA CompTox |
| Involatility Index | 0.0008💻 Calculated |
| log Kp (skin permeability) | -0.129💻 Calculated |
| SMILES | CCCCCCCCCC(C)C(OC)OC🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 5.2 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | aldehydicgreenlemonwaxy• leffingwell |
| Functional Groups | ether💻 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: DTXSID9052395
Physical Properties
| Molecular Weight | 230.392 g/mol🔬 EPA CompTox |
| Density | 0.829 g/cm^3📊 OPERA |
| Boiling Point | 255.858 °C📊 OPERA |
| Melting Point | -37.889 °C📊 OPERA |
| Flash Point | 83.293 °C📊 OPERA |
| Refractive Index | 1.428 Dimensionless📊 OPERA |
| Molar Volume | 273.108 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 5.243 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 5.243 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 5.243 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.89 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.013 mmHg📊 OPERA |
| Viscosity | 3.805 cP📊 OPERA |
| Surface Tension | 26.185 dyn/cm📊 OPERA |
| Thermal Conductivity | 134.411 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 | 11 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 70.317 cm^3/mol📊 OPERA |
| Polarizability | 27.876 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.
