p-Methyltetrahydroquinoline (CAS 91-61-2) — Woody Middle to base Note Fragrance Ingredient
p-Methyltetrahydroquinoline
CAS 91-61-2
What Is p-Methyltetrahydroquinoline?
p-Methyltetrahydroquinoline is a synthetic aromatic compound used in perfumery to add warm, woody, and slightly animalic nuances. It’s found in niche fragrances aiming for vintage or leathery accords. This ingredient matters because it provides a cost-effective alternative to natural animal-derived musks while offering unique tonalities that bridge floral and amber compositions.
Safety Profile
USE WITH AWARENESSWhat Does p-Methyltetrahydroquinoline Smell Like?
p-Methyltetrahydroquinoline opens with a sharp, phenolic edge reminiscent of antique books and ink, quickly softening into a warm core that evokes cured tobacco leaves and sun-baked leather. The dry-down reveals subtle powdery facets akin to orris root, with a lingering animalic whisper that behaves like a faint trace of castoreum. Over time, it develops a honeyed sweetness comparable to aged rum barrels.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Provides the vintage leather backbone, blending with birch tar and florals to create one of perfumery’s most legendary leather accords.
Used sparingly to enhance the birch leather illusion, adding depth to the floral bouquet without overwhelming the composition.
2D Molecular Structure
SMILES: CC1=CC2=C(NCCC2)C=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
p-Methyltetrahydroquinoline belongs to the quinoline class of heterocyclic compounds. Industrially produced via Skraup synthesis or hydrogenation of p-methylquinoline. The methyl group at the para position significantly impacts volatility and odor profile compared to unsubstituted tetrahydroquinoline. No chirality present in this molecule.
Physical & Chemical Properties
| Boiling Point | 248-250 °C |
|---|---|
| Density | 1.03 g/cm³ |
| Flash Point | >110 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | For leather/tobacco accords |
| Functional Fragrance | 0.05-0.2% | Up to 0.5% | Soap/cleaner applications |
Classic Accords
Tip: Use in trace amounts with ionones to create vintage lipstick effects.
Alternatives & Comparisons
When a greener, more floral-leaning leather note is desired without the animalic depth.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No current restrictions under IFRA 51st Amendment.
EU Allergen Declaration
Not listed in EU allergen regulation (EC) No 1223/2009.
GHS Classification
RIFM Assessment
RIFM reviewed – safe at current industry usage levels.
Sustainability
Synthetic production avoids agricultural impacts. Energy-intensive manufacturing requires proper waste management. Not biodegradable – persists in aquatic environments.
Explore p-Methyltetrahydroquinoline
Browse essential oils and aroma compounds.
Browse on iHerb →Affiliate disclosure: we may earn a small commission at no extra cost to you.
References
- Arctander, S. (1969). Perfume and Flavor Chemicals. Montclair: Steffen Arctander.
- IFRA Standards Library (2022). 51st Amendment. IFRA 51
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID6047444
Physical Properties
| Molecular Weight | 147.221 g/mol🔬 EPA CompTox |
| Density | 1.002 g/cm^3📊 OPERA |
| Boiling Point | 266.779 °C📊 OPERA |
| Melting Point | 35 °C🔬 EPA CTX |
| Flash Point | 110.624 °C📊 OPERA |
| Refractive Index | 1.54 Dimensionless📊 OPERA |
| Molar Volume | 148.571 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.571 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.25 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.567 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.77 Log10 unitless📊 OPERA |
| Water Solubility | 0.014 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.008 mmHg📊 OPERA |
| Viscosity | 6.077 cP📊 OPERA |
| Surface Tension | 36.012 dyn/cm📊 OPERA |
| Thermal Conductivity | 141.144 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 12.03 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 46.6 cm^3/mol📊 OPERA |
| Polarizability | 18.474 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.
