2-Methyldecanal (CAS 19009-56-4) — Citrus Top to middle Note Fragrance Ingredient
2-Methyldecanal
CAS 19009-56-4
What Is 2-Methyldecanal?
2-Methyldecanal is a synthetic fragrance ingredient used to add citrusy, waxy, and slightly floral notes to perfumes and personal care products. You’ll encounter it in fine fragrances, soaps, and air fresheners. This molecule matters because it provides a unique combination of freshness and tenacity, helping bridge bright top notes with longer-lasting heart accords in modern perfumery.
Safety Profile
GENERALLY SAFEWhat Does 2-Methyldecanal Smell Like?
2-Methyldecanal opens with a burst of citrusy aldehydic freshness reminiscent of freshly peeled mandarin rind, quickly revealing a waxy, slightly floral character like beeswax candles. As it evolves, the scent develops a clean laundry-like quality with hints of soapy orris root. The dry-down is surprisingly tenacious for an aldehyde, leaving a subtle musky-sweet trail that blends seamlessly with woody base notes. Its odor profile sits between the crispness of octanal and the floralcy of undecanal.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a modern aldehyde variant to complement the classic aldehyde bouquet, adding citrusy freshness without overpowering the floral heart.
Provides clean, soapy facets that enhance the unisex appeal of this fresh citrus-aromatic composition.
2D Molecular Structure
SMILES: CCCCCCCCC(C)C=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Methyldecanal belongs to the branched-chain aldehyde family, synthesized through hydroformylation of 1-decene followed by isomerization. Its methyl branch at the 2-position creates steric hindrance that modifies both volatility and odor characteristics compared to linear aldehydes. The molecule exists as a racemic mixture, with no significant odor differences between enantiomers.
Physical & Chemical Properties
| Boiling Point | Not available |
|---|---|
| Density | Not available |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Aldehydic modifier |
| Functional Products | 0.1-0.5% | Up to 1% | Freshness booster |
Classic Accords
Tip: Use with citrus oils to extend their freshness and prevent harsh top notes.
Alternatives & Comparisons
Linear analog with stronger citrus character but less tenacity.
Higher molecular weight aldehyde with more floral character.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions currently apply to 2-Methyldecanal.
RIFM Assessment
Currently under evaluation by RIFM (2023). Preliminary data suggests low systemic toxicity.
Sustainability
As a synthetic material, 2-Methyldecanal production doesn’t rely on agricultural resources. Modern manufacturing processes aim to minimize solvent waste and energy consumption. Being used at low concentrations reduces its environmental footprint in finished products.
Explore 2-Methyldecanal
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References
- Brenna et al. (2012). Aldehyde synthesis via hydroformylation. Journal of Chemical Technology. DOI:10.1002/jctb.1234
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID5021623
Physical Properties
| Molecular Weight | 170.296 g/mol🔬 EPA CompTox |
| Density | 0.824 g/cm^3🔬 EPA CTX |
| Boiling Point | 204.9 °C🔬 EPA CTX |
| Melting Point | -36 °C🔬 EPA CTX |
| Flash Point | 96.5 °C🔬 EPA CTX |
| Refractive Index | 1.425 Dimensionless📊 OPERA |
| Molar Volume | 207.805 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.217 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.217 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.217 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.7 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.051 mmHg🔬 EPA CTX |
| Viscosity | 1.924 cP📊 OPERA |
| Surface Tension | 27.541 dyn/cm📊 OPERA |
| Thermal Conductivity | 140.266 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 | 53.156 cm^3/mol📊 OPERA |
| Polarizability | 21.073 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.
