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IUPAC name Trimethylamine
Other names N,N-Dimethylmethanamine
Abbreviations TMA
CAS number 75-50-3
PubChem 1146
EINECS number 200-875-0
InChI InChI=1/C3H8N/c1-4(2)3/h1H2,2-3H3
Molecular formula C3H9N
Molar mass 59.11 g/mol
Appearance Clear colorless liquid
Density 0.67 g/ml (0 °C)
Melting point

-117.08 °C, 156 K, -179 °F

Boiling point

2.87 °C, 276 K, 37 °F

Solubility in water Miscible
Basicity (pKb) 4.13
NFPA 704
R-phrases R12 R20/22 R34
S-phrases (S1/2) S3 S16 S26 S29 S36/37/39 S45
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Trimethylamine, also known as NMe3, N(CH3)3, and TMA, is a colorless, hygroscopic, and flammable simple amine with a typical fishy odor in low concentrations and an ammonia-like odor in higher concentrations. Trimethylamine has a boiling point of 2.9 °C and is a gas at room temperature. Trimethylamine usually comes in pressurized gas cylinders or as a 40% solution in water. Trimethylamine is a nitrogenous base and its positively charged cation is called trimethylammonium cation. A common salt of trimethylamine is trimethylammonium chloride, a hygroscopic colorless solid.

Trimethylamine is a product of decomposition of plants and animals. It is the substance mainly responsible for the fishy odor often associated with fouling fish, bacterial vagina infections, and bad breath. It is also associated with taking large doses of choline and carnitine.

Additional recommended knowledge



Trimethylamine is used in the chemical synthesis of choline, tetramethylammonium hydroxide, plant growth regulators, strongly basic anion exchange resins, and dye leveling agents. Its fish-like odor has proven useful in applications such as the creation of gas sensors to test for fish freshness.


Main article: Trimethylaminuria

Trimethylaminuria is a genetic disorder in which the body is unable to metabolize trimethylamine from food sources. Patients develop a characteristic fish odour of their sweat, urine, and breath after the consumption of choline-rich foods. Trimethylaminuria is an autosomal recessive disorder involving a trimethylamine oxidase deficiency. A trimethylaminuria-like condition has also been observed in a certain breed of Rhode Island Red chicken that produces eggs with a fishy smell, especially after eating food containing a high proportion of rapeseed.

See also


  1. ^ Merck Index, 11th Edition, 9625.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Trimethylamine". A list of authors is available in Wikipedia.
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