earth science

Tetrachloro-1,1-difluoroethane

Tetrachloro-1,1-difluoroethane is a earth 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 Tetrachloro-1,1-difluoroethane rather than just read about it. In short: Tetrachloro-1,1-difluoroethane or 1,1,1,2-tetrachloro-2,2-difluoroethane, Freon 112a, R-112a, or CFC-112a is an asymmetric chlorofluorocarbon isomer of tetrachloro-1,1-difluoroethane with formula CClF2CCl3. It contains ethane substituted by four chlorine atoms and two fluorine atoms.

Key takeaways

Tetrachloro-1,1-difluoroethane belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tetrachloro-1,1-difluoroethane to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tetrachloro-1,1-difluoroethane from memory before moving on to harder problems.

Reference excerpt

Tetrachloro-1,1-difluoroethane or 1,1,1,2-tetrachloro-2,2-difluoroethane, Freon 112a, R-112a, or CFC-112a is an asymmetric chlorofluorocarbon isomer of tetrachloro-1,1-difluoroethane with formula CClF2CCl3. It contains ethane substituted by four chlorine atoms and two fluorine atoms. With a boiling point of 91.5°C it is the freon with second highest boiling point. Tetrachlorodifluoroethane as made is a mixture of the symmetrical and asymmetric isomers.

Preparation Tetrachloro-1,1-difluoroethane can be prepared in 40% yield by reacting 1,1,2-trichloro-1,2,2-trifluoroethane (freon 113) with aluminium chloride at 60°C. It can also be made in a reaction with hydrogen fluoride with hexachloroethane or tetrachloroethane with extra chlorine. This reaction occurs with an aluminium fluoride catalyst at 400°C. unsymmetrical trichlorotrifluoroethane (CCl2FCClF2) is also produced along with other chlorofluorocarbons. Separation of the symmetrical and unsymmetrical isomer is difficult.

Properties Tetrachloro-1,1-difluoroethane is non-combustible. It has a critical pressure of 4.83 MPa and a critical temperature of 279.2°C. At the critical point the density is 0.754 g/cm3. Tetrachloro-1,1-difluoroethane in liquid form is miscible with perfluorocarbons.

Reactions Tetrachloro-1,1-difluoroethane reacts with zinc in ethanol at 60°C to yield unsymmetrical dichlorodifluoroethylene (Cl2C=CF2).

Uses Tetrachlorodifluoroethane (CFC-112a), as with most high boiling point CFCs, has various uses as a non-flammable and clean agent solvent. It has historically been used as an extractant in liquid-liquid extraction and dry cleaning processes. CFC-112 and CFC-112a have also been used as feedstock chemicals in the manufacturing of fluorovinyl ethers. CFC-112a and its isomers are attractive organic solvents, as they have many important properties: they are nonflammable, clean drying, and have lower toxicity than common chlorinated organic solvents. Tetrachlorodifluoroethane (mixture of isomers) has a niche application as a veterinary medicine to treat parasites (Fasciola hepatica).

Atmosphere Tetrachloro-1,1-difluoroethane was first detected in air collected from Cape Grim, Tasmania in the Cape Grim Air Archive, and later from air bubbles in snow from Greenland. The substance made its first appearance around 1965, and increased in level until around 2000. In 2000 Earth's atmosphere contained 0.08 parts per trillion of Freon 112a. Level slightly declined to 0.07 ppt by 2012. Estimated lifetime in the stratosphere is 44 years. By 2014 3,600 tons of Freon 112a had been put into the atmosphere. As of 2023, levels have been rising in the Earth's atmosphere. As a greenhouse gas its radiative efficiency is 0.25 Wm−2ppb−1.

References

Extra reading Sládek, Petr; Navrátil, Oldřich; Linhart, Petr (1992). "Extraction of Selected Lanthanoids and Scandium with Bis(2-ethylhexyl)hydrogenphosphate in 1,1,2,2-Tetrachlorodifluoroethane". Collection of Czechoslovak Chemical Communications. 57 (8): 1647–1654. doi:10.1135/cccc19921647. Sládek, Petr; Navrátil, Oldřich; Linhart, Petr (1992). "Extraction of Ce, Pm, Eu, Tm and Sc Using Di-n-butylhydrogenphosphate in 1,1,2,2-Tetrachlorodifluoroethane". Collection of Czechoslovak Chemical Communications. 57 (8): 1639–1646. doi:10.1135/cccc19921639. Kakáč, B.; Hudlický, M. (1965). "Organic compounds of fluorine. VII. Spectrophotometric study in the series of halofluoroethanes". Collection of Czechoslovak Chemical Communications. 30 (3): 745–751. doi:10.1135/cccc19650745.

Illustrations

Worked examples

Example 1 — a first encounter with Tetrachloro-1,1-difluoroethane

Start with the simplest possible case. Write down what Tetrachloro-1,1-difluoroethane claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth 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 Tetrachloro-1,1-difluoroethane 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 Tetrachloro-1,1-difluoroethane 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 Tetrachloro-1,1-difluoroethane

In research: Tetrachloro-1,1-difluoroethane appears in earth 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 Tetrachloro-1,1-difluoroethane 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: Tetrachloro-1,1-difluoroethane is common in secondary-school and first-year university syllabi. It links to neighbouring topics Atmosphere of Earth, Chlorofluoroalkanes, Chlorofluorocarbons, so understanding it makes those chapters shorter.
In everyday life: Look for Tetrachloro-1,1-difluoroethane 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 Tetrachloro-1,1-difluoroethane in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tetrachloro-1,1-difluoroethane 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 Tetrachloro-1,1-difluoroethane out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tetrachloro-1,1-difluoroethane in simple terms?

Why does Tetrachloro-1,1-difluoroethane matter?

Because it connects several earth 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 Tetrachloro-1,1-difluoroethane?

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 Tetrachloro-1,1-difluoroethane.