science

Tetraethylammonium chloride

Tetraethylammonium chloride is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tetraethylammonium chloride rather than just read about it. In short: Tetraethylammonium chloride (TEAC) is a quaternary ammonium compound with the chemical formula [(CH3CH2)4N]Cl, sometimes written as [NEt4]Cl, where Et stands for ethyl. In appearance, it is a hygroscopic, colorless, crystalline solid.

Key takeaways

Tetraethylammonium chloride belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tetraethylammonium chloride to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tetraethylammonium chloride from memory before moving on to harder problems.

Reference excerpt

Tetraethylammonium chloride (TEAC) is a quaternary ammonium compound with the chemical formula [(CH3CH2)4N]Cl, sometimes written as [NEt4]Cl, where Et stands for ethyl. In appearance, it is a hygroscopic, colorless, crystalline solid. It consists of tetraethylammonium cations [(CH3CH2)4N]+ and chloride anions Cl−. It has been used as the source of tetraethylammonium 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 hydrochloride, small quantities of this compound form on heating of TEAC as the result of a Hofmann elimination:

Cl− + [N(CH2CH3)4]+ → HCl + H2C=CH2 + N(CH2CH3)3

Synthetic applications To a large extent, the synthetic applications of TEAC resemble those of tetraethylammonium bromide (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. 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 of carboxylic acids and certain heterocycles bearing an acidic N-H. Phase-transfer catalyst in geminal di-alkylation of fluorene, N,N-dialkylation of aniline and N-alkylation of carbazole using aqueous sodium hydroxide and alkyl halides.

Biology In common with tetraethylammonium bromide 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. Briefly, TEAC has been explored clinically for its ganglionic blocking 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 tetraethylammonium bromide and tetraethylammonium iodide. These data are provided for comparative purposes; additional details may be found in the entry for Tetraethylammonium.

See also Tetraethylammonium Tetraethylammonium bromide Tetraethylammonium iodide Tetramethylammonium chloride

References

Illustrations

Worked examples

Example 1 — a first encounter with Tetraethylammonium chloride

Start with the simplest possible case. Write down what Tetraethylammonium chloride claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tetraethylammonium chloride before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tetraethylammonium chloride ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tetraethylammonium chloride

In research: Tetraethylammonium chloride appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tetraethylammonium chloride in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tetraethylammonium chloride is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chlorides, Tetraethylammonium salts, so understanding it makes those chapters shorter.
In everyday life: Look for Tetraethylammonium chloride outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tetraethylammonium chloride in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tetraethylammonium chloride means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tetraethylammonium chloride out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tetraethylammonium chloride in simple terms?

Why does Tetraethylammonium chloride matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tetraethylammonium chloride?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tetraethylammonium chloride.