Trimethylamine (CAS 75-50-3) — Musky Top Note Fragrance Ingredient
Trimethylamine
CAS 75-50-3
What Is Trimethylamine?
Trimethylamine is a strong-smelling organic compound most recognized as the scent of decaying fish. People encounter it in seafood markets, certain industrial settings, and surprisingly, as a trace component in some perfumes where it’s used in minute amounts to create marine or animalic effects. Though unpleasant at high concentrations, skilled perfumers use trace amounts to add realism to oceanic or bodily accords, creating fragrances that feel alive and dynamic.
Safety Profile
PROFESSIONAL USEWhat Does Trimethylamine Smell Like?
Trimethylamine assaults the nose with an intensely fishy, ammoniacal stench at full strength – imagine overripe seafood left in the sun. However, when diluted to parts-per-million levels, it transforms into a complex marine note with animalic undertones. In perfumery, it’s used as a volatile top note that quickly dissipates into a lingering oceanic whisper, often blending with citrus or ozonic notes to create sea breeze effects. The dry-down reveals subtle urinous facets that can enhance leather or musk accords when carefully balanced.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used in trace amounts to enhance the salty, ambergris-like marine accord, contributing to the fragrance’s signature ‘skin by the sea’ effect without overt fishiness.
Employed at barely detectable levels to create the illusion of drying seaweed on warm rocks, adding realism to the aquatic composition.
2D Molecular Structure
SMILES: CN(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Trimethylamine (TMA) is a tertiary amine with the formula N(CH₃)₃. This simple molecule exists as a colorless gas at room temperature that readily dissolves in water, forming trimethylammonium hydroxide. Industrially produced by reacting methanol with ammonia over catalysts, it’s also naturally generated by bacterial decomposition of choline in fish. The molecule’s pyramidal structure and lone electron pair contribute to its strong nucleophilicity and distinctive fishy odor, detectable by humans at concentrations as low as 0.0001 ppm in air.
Physical & Chemical Properties
| Boiling Point | 2.9 °C |
|---|---|
| Density | 0.635 g/cm³ (gas) |
| Vapor Pressure | 1.6 atm (20°C) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.001-0.01% | Up to 0.05% | Marine/animalic accent |
| Functional Fragrance | Not used | N/A | Generally avoided |
Classic Accords
Tip: Always pre-dilute to 0.1% in ethanol before incorporating into blends to avoid overwhelming compositions.
Alternatives & Comparisons
Provides similar marine effects with less fishy intensity, useful when a subtler oceanic note is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not specifically restricted by IFRA but subject to general amine limitations under Amendment 49.
GHS Classification
RIFM Assessment
RIFM assessment recommends extreme caution due to respiratory and skin irritation potential at very low concentrations.
Sustainability
Primarily synthesized from petrochemical sources, though small amounts are captured from fish processing waste. Industrial production raises concerns about volatile organic compound emissions. Some research explores bio-based production using microbial fermentation of trimethylamine oxide.
Explore Trimethylamine
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References
- PubChem Compound Summary for Trimethylamine CID 1146
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 75-50-3Physical Properties
| Molecular Weight | 59.11 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 0.3🔬 PubChem |
| Boiling Point | 2.9 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -2.848💻 Calculated |
| SMILES | CN(C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
Odor & Flavor
| Primary Descriptors | fishypungent• leffingwell |
| Trimethylamine has a pungent, fishy, ammoniacal odor📖 Fenaroli | |
Sensory Thresholds
| Odor Detection Threshold | 0.032 ppm (n=21)📖 van Gemert |
Regulatory Status
| IOFI Classification | Nature Identical📖 Fenaroli |
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: DTXSID2026238
Physical Properties
| Molecular Weight | 59.112 g/mol🔬 EPA CompTox |
| Density | 0.639 g/cm^3🔬 EPA CTX |
| Boiling Point | 2.91 °C🔬 EPA CTX |
| Melting Point | -117.094 °C🔬 EPA CTX |
| Flash Point | -10.714 °C🔬 EPA CTX |
| Refractive Index | 1.378 Dimensionless📊 OPERA |
| Molar Volume | 85.309 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 0.085 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | -3.493 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | -2.148 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 2.08 Log10 unitless📊 OPERA |
| Water Solubility | 10.989 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 1330.666 mmHg🔬 EPA CTX |
| Viscosity | 0.197 cP📊 OPERA |
| Surface Tension | 19.582 dyn/cm📊 OPERA |
| Thermal Conductivity | 134.005 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 3.24 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 19.669 cm^3/mol📊 OPERA |
| Polarizability | 7.797 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.
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