Tetraethylammonium chloride (TEAC) is a

quaternary ammonium compound 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 catio ...

with the chemical formula (C₂H₅)₄N⁺Cl⁻, sometimes written as Et₄N⁺Cl⁻. In appearance, it is a hygroscopic, colorless, crystalline solid. It has been used as the source of

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 ...

ions in pharmacological and physiological studies, but is also used in organic chemical synthesis.

Preparation and structure

TEAC is produced by alkylation of triethylamine with ethyl chloride. TEAC exists as either of two stable hydrates, the monohydrate and tetrahydrate. The crystal structure of TEAC.H₂O has been determined, as has that of the tetrahydrate, TEAC.4H₂O. Details for the preparation of large, prismatic crystals of TEAC.H₂O are given by Harmon and Gabriele, who carried out IR-spectroscopic studies on this and related compounds. These researchers have also pointed out that, although freshly-purified TEAC.H₂O is free of

triethylamine Triethylamine is the chemical compound 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 or tetraethylammonium, for which TEA ...

hydrochloride, small quantities of this compound form on heating of TEAC as the result of a

Hofmann elimination Hofmann elimination is an elimination reaction of an amine to form alkenes. The least stable alkene (the one with the least number of substituents on the carbons of the double bond), called the Hofmann product, is formed. This tendency, known as ...

: :Cl⁻ + H-CH₂-CH₂-N⁺Et₃ → Cl-H + H₂C=CH₂ + Et₃N

Synthetic Applications

To a large extent, the synthetic applications of TEAC resemble those of

tetraethylammonium bromide Tetraethylammonium bromide (TEAB) is a quaternary ammonium compound with the chemical formula C8H20N+Br−, often written as "Et4N+Br−" in the chemical literature. It has been used as the source of tetraethylammonium ions in pharmacological and ...

(TEAB) and tetraethylammonium iodide (TEAI), although one of the salts may be more efficacious than another in a particular reaction. For example, TEAC produces better yields than TEAB or TEAI as a co-catalyst in a reaction to prepare diarylureas from arylamines, nitroaromatics and

carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...

. In other examples, such as the following, TEAC is not as effective as TEAB or TEAI: * 2-Hydroxyethylation (attachment of -CH₂-CH₂-OH) by

ethylene carbonate Ethylene carbonate (sometimes abbreviated EC) is the organic compound with the formula (CH2O)2CO. It is classified as the cyclic carbonate ester of ethylene glycol and carbonic acid. At room temperature (25 °C) ethylene carbonate is a tran ...

of carboxylic acids and certain heterocycles bearing an acidic N-H. *

Phase-transfer catalyst In chemistry, a phase-transfer catalyst or PTC is a catalyst that facilitates the transition of a reactant from one phase into another phase where reaction occurs. Phase-transfer catalysis is a special form of heterogeneous catalysis. Ionic r ...

geminal In chemistry, the descriptor geminal () refers to the relationship between two atoms or functional groups that are attached to the same atom. A geminal diol, for example, is a diol (a molecule that has two alcohol functional groups) attached t ...

di-

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 effecti ...

of fluorene, N,N-dialkylation of

aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starti ...

and N-alkylation of

carbazole Carbazole is an aromatic heterocyclic organic compound. It has a tricyclic structure, consisting of two six-membered benzene rings fused on either side of a five-membered nitrogen-containing ring. The compound's structure is based on the indole str ...

using aqueous sodium hydroxide and

alkyl halides The haloalkanes (also known as halogenoalkanes or alkyl halides) are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely us ...

Biology

In common with

and tetraethylammonium iodide, TEAC has been used as a source of tetraethylammonium ions for numerous clinical and pharmacological studies, which are covered in more detail under the entry for

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 ...

. Briefly, TEAC has been explored clinically for its

ganglionic blocking A ganglion is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system there are both sympathe ...

properties, although it is now essentially obsolete as a drug, and it is still used in physiological research for its ability to block K⁺ channels in various tissues.

Toxicity

The toxicity of TEAC is primarily due to the tetraethylammonium ion, which has been studied extensively. The acute toxicity of TEAC is comparable to that of

and tetraethylammonium iodide. These dataO. M. Gruhzit, R. A. Fisken and B. J. Cooper (1948). "Tetraethylammonium chloride C₂H₅)₄NCl Acute and chronic toxicity in experimental animals". ''J. Pharmacol. Exp. Ther.'' 92 103–107. are provided for comparative purposes; additional details may be found in the entry for

References

{{reflist Tetraethylammonium salts Chlorides

Preparation and structure

Synthetic Applications

Biology

Toxicity

See also

References