Trimethylamine

Trimethylamine, commonly abbreviated TMA, is an organonitrogen compound and a tertiary amine with the formula (CH3)3N. It is a colorless gas at room temperature with a characteristic fishy odor. It is soluble in water and many organic solvents and acts as a weak base in aqueous solution.

In nature, TMA is produced by microbial decomposition of nitrogen-containing compounds. In seafood, bacteria reduce trimethylamine N-oxide (TMAO) to TMA, contributing to the characteristic smell of spoiled fish. In humans, gut bacteria generate TMA from dietary choline, carnitine, and betaine; the liver oxidizes much of this TMA to trimethylamine N-oxide (TMAO) via the enzyme flavin-containing monooxygenase 3 (FMO3). Defects in FMO3 cause trimethylaminuria, a condition in which TMA accumulates and is excreted in breath and urine, producing a persistent fishy odor.

Industrial production of TMA is typically achieved by methylation and ammoniation processes that yield mixtures of methylamines, from which trimethylamine is separated. It serves as a versatile industrial chemical intermediate, used to manufacture quaternary ammonium compounds such as surfactants and disinfectants, and as a precursor in the synthesis of pharmaceuticals and specialized reagents.

Safety considerations include its high flammability and irritant properties. Exposure can irritate the eyes, skin, and respiratory tract and may cause headaches or dizziness. It is also toxic to aquatic life. Adequate ventilation and appropriate protective equipment are recommended when handling trimethylamine.