chemistry

Hexafluoroacetone

Hexafluoroacetone 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 Hexafluoroacetone rather than just read about it. In short: Hexafluoroacetone (HFA) is a chemical compound with the formula (CF3)2CO. It is structurally similar to acetone; however, its reactivity is markedly different.

Key takeaways

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

Reference excerpt

Hexafluoroacetone (HFA) is a chemical compound with the formula (CF3)2CO. It is structurally similar to acetone; however, its reactivity is markedly different. It is a colourless, hygroscopic, nonflammable, highly reactive gas characterized by a musty odour. According to electron diffraction, HFA and acetone adopt very similar structures, the C-O distance being only longer in the fluorinated compound (124.6 vs 121.0 pm), possibly due to steric effects. The term "hexafluoroacetone" can refer to the sesquihydrate (1.5 H2O), which is a hemihydrate of hexafluoropropane-2,2-diol (F3C)2C(OH)2, a geminal diol. Hydrated HFA behaves differently from the anhydrous material.

Synthesis The industrial route to HFA involves treatment of hexachloroacetone with HF:

(CCl3)2CO + 6 HF → (CF3)2CO + 6 HCl

Laboratory methods Hydrated HFA can be converted to HFA by treatment with hot sulfuric acid. It has also be prepared from hexafluoropropylene oxide, which will rearrange to give HFA when heated in the presence of a Lewis acid such as AlCl3. The Lewis acid catalysed oxidation of hexafluoropropylene will also produce HFA, via a similar mechanism. Although it is commercially available, HFA can be prepared on the laboratory-scale from hexafluoropropylene. In the first step KF catalyzes the reaction of the alkene with elemental sulfur to give the 1,3-dithietane dimer of hexafluorothioacetone. This species is then oxidized by potassium iodate to give HFA.

Uses Hexafluoroacetone is used in the production of hexafluoroisopropanol:

(CF3)2CO + H2 → (CF3)2CHOH It is also used as a precursor to hexafluoroisobutylene, a monomer used in polymer chemistry, and as a building block in the synthesis of midaflur, bisphenol AF, 4,4′-(hexafluoroisopropylidene)diphthalic anhydride, and alitame.

Reactivity

With water, hexafluoroacetone converts to the hydrate. The equilibrium constant (Keq) for the formation of this geminal diol is 106 M−1. The analogous equilibrium for acetone is an unfavorable 10−3 M−1. Hexafluoroacetone-hydrates are acidic. In an analogous reaction, ammonia adds to hexafluoroacetone to give the hemiaminal (CF3)2C(OH)(NH2) which can be dehydrated with phosphoryl chloride to give the imine (CF3)2CNH. Nucleophiles attack occurs at the carbonyl carbon of hexafluoroacetone, as illustrated above. Thus, HFA readily forms lactones when treated with hydroxy- and amine-substituted carboxylic acids. In such reactions, HFA serves both as electrophile and dehydrating agent:

RCH(OH)CO2H + O=C(CF3)2 → RCH(O)CO2C(CF3)2 + (HO)2C(CF3)2

See also Bromoacetone Chloroacetone Fluoroacetone Trifluoroacetone Novec 1230 Hexafluorothioacetone

References

Illustrations

Worked examples

Example 1 — a first encounter with Hexafluoroacetone

Start with the simplest possible case. Write down what Hexafluoroacetone 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 Hexafluoroacetone 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 Hexafluoroacetone 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 Hexafluoroacetone

In research: Hexafluoroacetone 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 Hexafluoroacetone 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: Hexafluoroacetone is common in secondary-school and first-year university syllabi. It links to neighbouring topics Carbon oxohalides, Ketones, Perfluorinated compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Hexafluoroacetone 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 Hexafluoroacetone in 20 minutes

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

Frequently asked questions

What is Hexafluoroacetone in simple terms?

Hexafluoroacetone (HFA) is a chemical compound with the formula (CF3)2CO. It is structurally similar to acetone; however, its reactivity is markedly different.

Why does Hexafluoroacetone 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 Hexafluoroacetone?

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 Hexafluoroacetone.