chemistry

Triphenylmethane

Triphenylmethane is a chemistry 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 Triphenylmethane rather than just read about it. In short: Triphenylmethane or triphenyl methane (sometimes also known as Tritan), is the hydrocarbon with the formula (C6H5)3CH. This colorless solid is soluble in nonpolar organic solvents and not in water.

Key takeaways

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

Reference excerpt

Triphenylmethane or triphenyl methane (sometimes also known as Tritan), is the hydrocarbon with the formula (C6H5)3CH. This colorless solid is soluble in nonpolar organic solvents and not in water. Triphenylmethane is the basic skeleton of many synthetic dyes called triarylmethane dyes, many of them are pH indicators, and some display fluorescence. A trityl group in organic chemistry is a triphenylmethyl group Ph3C, e.g. triphenylmethyl chloride (trityl chloride) and the triphenylmethyl radical (trityl radical).

Preparation Triphenylmethane was first synthesized by heating diphenylmercury (Hg(C6H5)2, Quecksilberdiphenyl) with benzal chloride (C6H5CHCl2, Benzylenchlorid). It can be synthesized by Friedel–Crafts reaction from benzene and chloroform in the presence of aluminium chloride catalyst:

3 C6H6 + CHCl3 → Ph3CH + 3 HCl Alternatively, benzene may react with carbon tetrachloride using the same catalyst to obtain the triphenylmethyl chloride–aluminium chloride adduct which is then treated with diethyl ether for 24 hours at room temperature and hydrolyzed with concentrated hydrochloric acid:

3 C6H6 + CCl4 + AlCl3 → Ph3CCl·AlCl3 Ph3CCl·AlCl3 + Et2O + HCl → Ph3CH It can also be synthesized from benzal chloride, which is prepared from benzaldehyde and phosphorus pentachloride.

Reactions of C-H bond The Ph3C-H bond is relatively weak, with a bond dissociation energy (BDE) of 81 kcal/mol, or about 24 kcal/mol less than methane. Correspondingly, triphenylmethane is relatively acidic, with a pKa of 33. Triphenylmethane is significantly more acidic than most other hydrocarbons because the charge is delocalized over three phenyl rings. Steric effects however prevent all three phenyl rings from achieving coplanarity simultaneously. Consequently diphenylmethane is even more acidic, albeit only slightly, because in its anion the charge is spread over two phenyl rings at the same time. The trityl anion is isolable in crown ethers:

Its sodium salt can be prepared from the chloride:

(C6H5)3CCl + 2 Na → (C6H5)3CNa + NaCl The use of tritylsodium as a strong, non-nucleophilic base has been eclipsed by the popularization of butyllithium and related strong bases. The unmodified anion is red, and can be used as an indicator in acid–base titrations. Derived substances have proven useful as chemical dyes.

Triarylmethane dyes

Examples of triarylmethane dyes are bromocresol green:

And the nitrogen-bearing malachite green:

Trityl group

Protecting group The triphenylmethyl substituent, also called trityl after a 1927 suggestion by Helferich et al., is widely used in organic chemistry. Trityl serves as a protecting group for alcohols.

protection (requires proton acceptor): Ph3CCl + ROH → Ph3COR + HCl deprotection: Ph3COR + HBr → ROH + Ph3CBr

Platform for unusual functional groups Trityl derivatives of reactive functional groups are often crystalline and in some cases sterically stabilized relative to less bulky derivatives. Three such derivatives are S-nitrosotriphenylmethanethiol (Ph3CSNO), tritylsulfenyl chloride (Ph3CSCl), and trityl sulfenamide (Ph3CSNH2).

See also Tetraphenylmethane Triphenylmethanol Triphenylmethyl chloride Triphenylmethyl hexafluorophosphate Triphenylmethyl radical

References

Illustrations

Worked examples

Example 1 — a first encounter with Triphenylmethane

Start with the simplest possible case. Write down what Triphenylmethane claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, 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 Triphenylmethane 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 Triphenylmethane 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 Triphenylmethane

In research: Triphenylmethane appears in chemistry 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 Triphenylmethane 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: Triphenylmethane is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aromatic hydrocarbons, Phenyl compounds, Substances discovered in the 19th century, so understanding it makes those chapters shorter.
In everyday life: Look for Triphenylmethane 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 Triphenylmethane in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Triphenylmethane 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 Triphenylmethane out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Triphenylmethane in simple terms?

Triphenylmethane or triphenyl methane (sometimes also known as Tritan), is the hydrocarbon with the formula (C6H5)3CH. This colorless solid is soluble in nonpolar organic solvents and not in water.

Why does Triphenylmethane matter?

Because it connects several chemistry 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 Triphenylmethane?

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 Triphenylmethane.