2,6,10-Trimethyl-9-undecenal (CAS 141-13-9) — Citrus Top to Middle Note Fragrance Ingredient
2,6,10-Trimethyl-9-undecenal
CAS 141-13-9
What Is 2,6,10-Trimethyl-9-undecenal?
2,6,10-Trimethyl-9-undecenal is a synthetic fragrance ingredient primarily used in fine perfumery. It’s found in modern floral and citrus-based fragrances, often adding a fresh, aldehydic lift. This molecule matters because it provides a unique metallic-citrus character that helps bridge floral and woody accords, creating contemporary scent profiles that feel both clean and sophisticated.
Safety Profile
GENERALLY SAFEWhat Does 2,6,10-Trimethyl-9-undecenal Smell Like?
A razor-sharp aldehyde with paradoxical character – imagine grapefruit zest electrified by a metallic wire, cooling into a waxy-clean impression reminiscent of freshly laundered linen. The opening is aggressively citrus-floral, like bergamot oil spilled on stainless steel, which gradually softens into a subtle marine-like dryness. In dilution, it reveals a sophisticated ambergris-like nuance that makes it invaluable for modern amber bases.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to modernize the classic aldehydic bouquet, adding a crisp, contemporary edge that bridges the citrus top notes and floral heart.
Provides luminous freshness to the floral bouquet, enhancing the peony and orchid notes with a metallic-clean accent.
2D Molecular Structure
SMILES: CC(CCCC(C)C=O)CCC=C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
A branched-chain unsaturated aldehyde with the molecular formula C14H26O. Synthesized via aldol condensation reactions from commercially available precursors. The 2,6,10-trimethyl substitution pattern creates steric hindrance that influences both its reactivity and odor profile. No chiral centers present in this molecule. Industrial synthesis typically involves controlled oxidation of the corresponding alcohol precursor.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | ~230 °C (estimated) |
| Density | ~0.85 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Powerful modifier rather than main note |
| Functional Fragrance | 0.1-0.5% | Up to 1% | For fresh linen effects |
Classic Accords
Tip: Add to ethanol base 24 hours before final blending to allow aldehyde reactions to stabilize.
Alternatives & Comparisons
When a less metallic, more floral-aldehydic character is desired. Has similar longevity but smoother profile.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No current IFRA restrictions. Last reviewed under Amendment 49.
RIFM Assessment
RIFM assessment complete – no significant safety concerns at typical usage levels.
Sustainability
Synthesized from petrochemical feedstocks via efficient catalytic processes. No known environmental accumulation issues. Biodegradation studies show moderate environmental persistence. Carbon footprint comparable to other specialty fragrance aldehydes. No animal-derived components used in production.
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References
- Brenna et al. (2012). Structure-Odor Relationships in Branched-Chain Aldehydes. Journal of Agricultural and Food Chemistry. DOI: 10.1021/jf204250z
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID7051711
Physical Properties
| Molecular Weight | 210.361 g/mol🔬 EPA CompTox |
| Density | 0.856 g/cm^3🔬 EPA CTX |
| Boiling Point | 260 °C🔬 EPA CTX |
| Melting Point | 10.405 °C📊 OPERA |
| Flash Point | 112.532 °C📊 OPERA |
| Refractive Index | 1.446 Dimensionless📊 OPERA |
| Molar Volume | 251.118 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 5.454 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 5.454 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 5.454 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.9 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.003 mmHg🔬 EPA CTX |
| Viscosity | 4.485 cP📊 OPERA |
| Surface Tension | 26.428 dyn/cm📊 OPERA |
| Thermal Conductivity | 133.577 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 | 8 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 66.914 cm^3/mol📊 OPERA |
| Polarizability | 26.527 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.
