Trimethylamine (TMA) is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

with the formula N(CH₃)₃. It is a colorless,

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...

, and flammable tertiary amine. It is a gas at room temperature but is usually sold as a 40%

solution Solution may refer to: * Solution (chemistry), a mixture where one substance is dissolved in another * Solution (equation), in mathematics ** Numerical solution, in numerical analysis, approximate solutions within specified error bounds * Solutio ...

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...

. (It is also sold in pressurized

gas cylinder A gas cylinder is a pressure vessel for storage and containment of gases at above atmospheric pressure. High-pressure gas cylinders are also called ''bottles''. Inside the cylinder the stored contents may be in a state of compressed gas, vap ...

s.) TMA is a nitrogenous base and can be readily protonated to give the trimethylammonium cation. Trimethylammonium chloride is a hygroscopic colorless solid prepared from

hydrochloric acid Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid. It is a component of the gastric acid in the dige ...

. Trimethylamine is a good

nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they ar ...

, and this reaction is the basis of most of its applications. TMA is widely used in industry: it is used in the synthesis of choline,

tetramethylammonium hydroxide Tetramethylammonium hydroxide (TMAH or TMAOH) is a quaternary ammonium salt with molecular formula N(CH3)4+ OH−. It is commonly encountered in form of concentrated solutions in water or methanol. TMAH in solid state and its aqueous solu ...

, plant growth regulators or

herbicide Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page f ...

s, strongly basic anion exchange resins,

dye A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and ...

leveling agents, and a number of basic dyes. At higher concentrations it has an

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous ...

-like odor, and can cause necrosis of mucous membranes on contact. At lower concentrations, it has a "fishy" odor, the odor associated with rotting

fish Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as we ...

. In humans, ingestion of certain plant and animal (e.g., red meat, egg yolk) food containing

lecithin Lecithin (, from the Greek ''lekithos'' "yolk") is a generic term to designate any group of yellow-brownish fatty substances occurring in animal and plant tissues which are amphiphilic – they attract both water and fatty substances (and so a ...

, choline and

L-carnitine Carnitine is a quaternary ammonium compound involved in metabolism in most mammals, plants, and some bacteria. In support of energy metabolism, carnitine transports long-chain fatty acids into mitochondria to be oxidized for energy production, an ...

provides certain gut microbiota with the substrate to synthesize TMA, which is then absorbed into the bloodstream. High levels of trimethylamine in the body are associated with the development of trimethylaminuria, or fish odor syndrome, caused by a genetic defect in the enzyme which degrades TMA; or by taking large doses of supplements containing choline or

. TMA is metabolized by the liver to trimethylamine N-oxide (TMAO); TMAO is being investigated as a possible pro

atherogenic Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually no ...

substance which may accelerate atherosclerosis in those eating foods with a high content of TMA precursors. TMA also causes the odor of some human

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable di ...

s, bad breath, and

bacterial vaginosis Bacterial vaginosis (BV) is a disease of the vagina caused by excessive growth of bacteria. Common symptoms include increased vaginal discharge that often smells like fish. The discharge is usually white or gray in color. Burning with urinati ...

. Trimethylamine is a

full agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the a ...

of human TAAR5,
Table 2: Microbial metabolites: their synthesis, mechanisms of action, and effects on health and disease
br
Figure 1: Molecular mechanisms of action of indole and its metabolites on host physiology and disease
/ref> a trace amine-associated receptor that is expressed in the olfactory epithelium and functions as an olfactory receptor for tertiary amines. One or more additional odorant receptors appear to be involved in trimethylamine olfaction in humans as well.

Production

Trimethylamine is prepared by the reaction of

and

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is ...

employing a catalyst: :3 CH₃OH + NH₃ → (CH₃)₃N + 3 H₂O This reaction coproduces the other methylamines,

dimethylamine Dimethylamine is an organic compound with the formula (CH3)2NH. This secondary amine is a colorless, flammable gas with an ammonia-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to arou ...

(CH₃)₂NH and methylamine CH₃NH₂. Trimethylamine has also been prepared by a reaction of ammonium chloride and

paraformaldehyde Paraformaldehyde (PFA) is the smallest polyoxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8–100 units. Paraformaldehyde commonly has a slight odor of formaldehyde due to decomposition. Par ...

: : 9 (CH₂=O)_n + 2n NH₄Cl → 2n (CH₃)₃N•HCl + 3n H₂O + 3n CO₂↑

Toxicity

Acute and chronic toxic effects of TMA were suggested in medical literature as early as the 19th century. TMA causes eye and skin irritation, and it is suggested to be a

uremic toxin Uremia is the term for high levels of urea in the blood. Urea is one of the primary components of urine. It can be defined as an excess of amino acid and protein metabolism end products, such as urea and creatinine, in the blood that would be nor ...

. In patients, trimethylamine caused stomach ache, vomiting, diarrhoea, lacrimation, greying of the skin and agitation. Apart from that, reproductive/

developmental toxicity Development of the human body is the process of growth to maturity. The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through mitosi ...

has been reported. Guidelines with exposure limit for workers are available e.g. the Recommendation from the Scientific Committee on Occupational Exposure Limits by the European Union Commission. Some experimental studies suggested that TMA may be involved in etiology of

cardiovascular disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, hea ...

Applications

Trimethylamine is used in the synthesis of choline,

, plant growth regulators,

s, strongly basic anion exchange resins,

leveling agents and a number of basic dyes. Gas sensors to test for fish freshness detect trimethylamine.

Reactions

Trimethylamine is a

Lewis base A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any sp ...

that forms

adducts An adduct (from the Latin ''adductus'', "drawn toward" alternatively, a contraction of "addition product") is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all co ...

with a variety of Lewis acids.

Trimethylaminuria

Trimethylaminuria is an autosomal

recessive In genetics, dominance is the phenomenon of one variant ( allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant an ...

genetic disorder A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...

involving a defect in the function or expression of flavin-containing monooxygenase 3 (FMO3) which results in poor trimethylamine

metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run ...

. Individuals with trimethylaminuria develop a characteristic fish odor—the smell of trimethylamine—in their sweat,

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellul ...

, and

breath Breathing (or ventilation) is the process of moving air into and from the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen. All aerobic creatures need oxygen for cellu ...

after the consumption of choline-rich foods. A condition similar to trimethylaminuria has also been observed in a certain breed of

Rhode Island Red The Rhode Island Red is an American breed of domestic chicken. It is the state bird of Rhode Island. It was developed there and in Massachusetts in the late nineteenth century, by cross-breeding birds of Oriental origin such as the Malay with ...

chicken that produces eggs with a fishy smell, especially after eating food containing a high proportion of rapeseed.

References

External links

Molecule of the Month: Trimethylamine

NIST Webbook data

{{Authority control Pesticides Dimethylamino compounds Foul-smelling chemicals