Triethylamine is the

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the formula N(CH₂CH₃)₃, commonly abbreviated Et₃N. It is also abbreviated TEA, yet this abbreviation must be used carefully to avoid confusion with

triethanolamine Triethanolamine, or TEA is a viscous organic compound that is both a tertiary amine and a triol. A triol is a molecule with three alcohol groups. Approximately 150,000 tonnes were produced in 1999. It is a colourless compound although samples m ...

tetraethylammonium Tetraethylammonium (TEA), () or (Et4N+) is a quaternary ammonium cation consisting of four ethyl groups attached to a central nitrogen atom, and is positively charged. It is a counterion used in the research laboratory to prepare lipophilic salts ...

, for which TEA is also a common abbreviation. It is a colourless volatile liquid with a strong fishy odor reminiscent of

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 was ...

. Like

diisopropylethylamine ''N'',''N''-Diisopropylethylamine, or Hünig's base, is an organic compound and an amine. It is named after the German chemist Siegfried Hünig. It is used in organic chemistry as a base. It is commonly abbreviated as DIPEA, DIEA, or ''i''-Pr2N ...

(Hünig's base), triethylamine is commonly employed in organic synthesis, usually as a base.

Synthesis and properties

Triethylamine is prepared by the

alkylation Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecting ...

of ammonia with

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...

: :NH₃ + 3 C₂H₅OH → N(C₂H₅)₃ + 3 H₂O The pK_a of protonated triethylamine is 10.75,David Evans Research Group
and it can be used to prepare buffer solutions at that pH. The

hydrochloride In chemistry, a hydrochloride is an acid salt resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base (e.g. an amine). An alternative name is chlorhydrate, which comes from French. An archaic alternative n ...

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

, triethylamine hydrochloride (triethylammonium chloride), is a colorless, odorless, and

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 substan ...

powder, which decomposes when heated to 261 °C. Triethylamine is soluble in water to the extent of 112.4 g/L at 20 °C. It is also miscible in common organic solvents, such as acetone, ethanol, and diethyl ether. Laboratory samples of triethylamine can be purified by distilling from

calcium hydride Calcium hydride is the chemical compound with the formula , and is therefore an alkaline earth hydride. This grey powder (white if pure, which is rare) reacts vigorously with water liberating hydrogen gas. is thus used as a drying agent, i.e. a d ...

. In alkane solvents triethylamine is a Lewis base that forms adducts with a variety of Lewis acids, such as I₂ and

phenols In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (— O H) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, . Phenolic compounds are ...

. Owing to its steric bulk, it forms complexes with transition metals reluctantly.

Applications

Triethylamine is commonly employed in organic synthesis as a base. For example, it is commonly used as a base during the preparation of

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

s and

amide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it i ...

s from acyl chlorides. Such reactions lead to the production of

hydrogen chloride The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride ga ...

which combines with triethylamine to form the salt triethylamine hydrochloride, commonly called triethylammonium chloride. Hydrogen chloride may then evaporate from the reaction mixture, which drives the reaction. (R, R' =

alkyl In organic chemistry, an alkyl group is an alkane missing one hydrogen. The term ''alkyl'' is intentionally unspecific to include many possible substitutions. An acyclic alkyl has the general formula of . A cycloalkyl is derived from a cycloalk ...

aryl In organic chemistry, an aryl is any functional group or substituent derived from an aromatic ring, usually an aromatic hydrocarbon, such as phenyl and naphthyl. "Aryl" is used for the sake of abbreviation or generalization, and "Ar" is used as ...

): :R₂NH + R'C(O)Cl + Et₃N → R'C(O)NR₂ + Et₃NH⁺Cl⁻ Like other tertiary amines, it catalyzes the formation of urethane foams and epoxy resins. It is also useful in

dehydrohalogenation In chemistry, dehydrohalogenation is an elimination reaction which removes a hydrogen halide from a substrate. The reaction is usually associated with the synthesis of alkenes, but it has wider applications. Dehydrohalogenation from alkyl halid ...

reactions and

Swern oxidation The Swern oxidation, named after Daniel Swern, is a chemical reaction whereby a primary or secondary alcohol is oxidized to an aldehyde or ketone using oxalyl chloride, dimethyl sulfoxide (DMSO) and an organic base, such as triethylamine. It is one ...

s. Triethylamine is readily alkylated to give the corresponding

quaternary ammonium salt In chemistry, quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure , R being an alkyl group or an aryl group. Unlike the ammonium ion () and the primary, secondary, or tertiary ammonium cation ...

: :RI + Et₃N → Et₃NR⁺I⁻ Triethylamine is mainly used in the production of quaternary ammonium compounds for textile auxiliaries and quaternary ammonium salts of dyes. It is also a

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

and acid neutralizer for

condensation reaction In organic chemistry, a condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reaction is also known as a ...

s and is useful as an intermediate for manufacturing medicines,

pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...

s and other chemicals. Triethylamine salts, like any other tertiary ammonium salts, are used as an ion-interaction reagent in

ion interaction chromatography Ion interaction chromatography (ion-pair chromatography) is a laboratory technique for separating ions with chromatography. In this technique ions are mixed with ion pairing reagents (IPR). The analyte combines with its reciprocal ion in the IPR, t ...

, due to their amphiphilic properties. Unlike quaternary ammonium salts, tertiary ammonium salts are much more volatile, therefore

mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is use ...

can be used while performing analysis.

Niche uses

Triethylamine is used to give salts of various carboxylic acid-containing pesticides, e.g.

Triclopyr Triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) is an organic compound in the pyridine group that is used as a systemic foliar herbicide and fungicide. Uses Triclopyr is used to control broadleaf weeds while leaving grasses and conifers ...

and 2,4-dichlorophenoxyacetic acid Triethylamine is the active ingredient in FlyNap, a product for anesthetizing ''

Drosophila melanogaster ''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly" or "pomace fly". Starting with Ch ...

''. Triethylamine is used in mosquito and vector control labs to anesthetize mosquitoes. This is done to preserve any viral material that might be present during species identification. The

bicarbonate In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial biochem ...

of triethylamine (often abbreviated TEAB, triethylammonium bicarbonate) is useful in reverse phase chromatography, often in a gradient to purify nucleotides and other biomolecules. Triethylamine was found during the early 1940s to be

hypergolic A hypergolic propellant is a rocket propellant combination used in a rocket engine, whose components spontaneously ignite when they come into contact with each other. The two propellant components usually consist of a fuel and an oxidizer. T ...

in combination with nitric acid, and was considered a possible propellant for early hypergolic rocket engines. The Soviet "Scud" Missile used TG-02 ("Tonka-250"), a mixture of 50%

xylidine Xylidine can refer to any of the six isomers of xylene amine, or any mixture of them. The chemical formula of xylidines is C8H11N or, more descriptively, (CH3)2C6H3NH2. The CAS number for the isomer mixture is . They are colorless solids or liqui ...

and 50% triethlyamine as a starting fluid to ignite its rocket engine.

Natural occurrence

Hawthorn flowers have a heavy, complicated scent, the distinctive part of which is triethylamine, which is also one of the first chemicals produced by a dead human body when it begins to decay. Due to the scent , it is considered unlucky to bring hawthorn into a house.

Gangrene Gangrene is a type of tissue death caused by a lack of blood supply. Symptoms may include a change in skin color to red or black, numbness, swelling, pain, skin breakdown, and coolness. The feet and hands are most commonly affected. If the ga ...

and

semen Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Semen i ...

are also said to possess a similar odour.The book of general ignorance. John Lloyd & John Mitchinson. Faber & Faber 2006
The Hawthorn
BBC

References

External links

{{Authority control Alkylamines Tertiary amines