Tetrachloro-1,2-difluoroethane is a

chlorofluorocarbon Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly Halogenation, halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F). They are produced as volatility (chemistry), volat ...

known as Freon 112, CFC-112 or R-112. It has a symmetrical structure CCl₂FCCl₂F and so can be called symmetrical tetrachlorodifluoroethane. "Symmetrical" may also be abbreviated to "s-" or "sym-". In contrast an asymmetrical isomer has formula CCl₃CClF₂.

Production

CFC-112 can be made in a reaction of

hexachloroethane Hexachloroethane (perchloroethane) is an organochlorine compound with the chemical formula . Its structure is . It is a white or colorless solid at room temperature with a camphor-like odor. It has been used by the military in smoke compositions, ...

tetrachloroethane Tetrachloroethane () may refer to either of two isomeric chemical compounds: * 1,1,1,2-Tetrachloroethane (R-130a) * 1,1,2,2-Tetrachloroethane (R-130) See also * Tetrachloroethene * Trichloroethane * Tetrafluoroethane * Tetrabromoethane 1,1,2,2-Te ...

with hydrogen fluoride and extra chlorine. This reaction is catalysed by

aluminium fluoride Aluminium fluoride is an inorganic compound with the formula . It forms hydrates . Anhydrous and its hydrates are all colorless solids. Anhydrous is used in the production of aluminium. Several occur as minerals. Occurrence and production Aside ...

with some extra iron, nickel and chromium at 400°C. The extra metal in the catalyst yields can be 98% compared with the unsymmetrical isomer. Mixed with

perfluorooctane Perfluorooctane, also known as octadecafluorooctane, is a fluorocarbon liquid—a perfluorinated derivative of the hydrocarbon octane. It can be a good substitute for insulating oil in high voltage electronics. In addition to heat transfer app ...

, it is a solvent for

polydimethylsiloxane Polydimethylsiloxane (PDMS), also known as dimethylpolysiloxane or dimethicone, is a silicone polymer with a wide variety of uses, from cosmetics to industrial lubrication and passive daytime radiative cooling. PDMS is particularly known for its ...

. CFC-112 can be prepared as a mixture with other

hydrochlorofluorocarbon Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F). They are produced as volatile derivatives of methane, ethane, ...

s from

trichloroethylene Trichloroethylene (TCE) is an organochloride with the formula C2HCl3, commonly used as an industrial metal-degreasing solvent. It is a clear, colourless, non-flammable, volatile liquid with a chloroform-like pleasant mild smell and sweet taste.

and anhydrous

hydrogen fluoride Hydrogen fluoride (fluorane) is an Inorganic chemistry, inorganic compound with chemical formula . It is a very poisonous, colorless gas or liquid that dissolves in water to yield hydrofluoric acid. It is the principal industrial source of fluori ...

when electric current is passed through. When CFC-11 is packaged with alcohol in a metal container, a free radical reaction can result in production of CFC-112.

Properties

Critical properties are critical temperature 278°C, critical pressure 4.83 MPa at a density of 0.754 g/cc. Tetrachloro-1,2-difluoroethane is not flammable. Tetrachloro-1,2-difluoroethane, like other chlorofluorocarbon compounds reacts violently with sodium, potassium or barium. Tetrachloro-1,2-difluoroethane is not very toxic, and the lethal dose is estimated at 25 g/kg. It is not carcinogenic.

Use

Tetrachlorodifluoroethane (mixture of isomers) has been used as a veterinary medicine to treat parasites such as liver fluke in sheep (''

Fasciola hepatica ''Fasciola hepatica'', also known as the common liver fluke or sheep liver fluke, is a parasitism, parasitic trematode (fluke (flatworm), fluke or flatworm, a type of helminth) of the class (biology), class Trematoda, phylum Platyhelminthes. It ...

''). MIL-C-8638 is a military specification for a cleaning solvent that contained tetrachlorodifluoroethane, trichlorotrifluoroethane, and

isopropyl alcohol Isopropyl alcohol (IUPAC name propan-2-ol and also called isopropanol or 2-propanol) is a colorless, flammable, organic compound with a pungent alcoholic odor. Isopropyl alcohol, an organic polar molecule, is miscible in water, ethanol, an ...

. It was used to clean aircraft oxygen systems. Tetrachlorodifluoroethane can be used as an intermediate in the manufacture of

tetrachloroethylene Tetrachloroethylene, also known as perchloroethylene or under the systematic name tetrachloroethene, and abbreviations such as perc (or PERC), and PCE, is a chlorocarbon with the formula . It is a non-flammable, stable, colorless and heavy liqu ...

Atmosphere

In the atmosphere of Earth, anthropogenic tetrachloro-1,2-difluoroethane has been found to occur. Between 2017 and 2020 levels, were about 0.52 parts per trillion (ppt). Levels rose from the 1970s until about 1995.

References

{{Reflist Chlorofluorocarbons Ozone-depleting chemical substances Chlorofluoroalkanes