| Dichlorodifluoromethane | |
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Dichlorodifluoromethane |
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Other names
Carbon dichloride difluoride, Dichloro-difluoro-methane, Difluorodichloromethane, Freon 12, R-12, CFC-12, P-12, Propellant 12, Halon 122, Arcton 6, Arcton 12, E940 |
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| Identifiers | |
| CAS number | 75-71-8 |
| PubChem | 6391 |
| ChemSpider | 6151 |
| UNII | OFM06SG1KO |
| EC number | 200-893-9 |
| UN number | 1028 |
| KEGG | D03789 |
| RTECS number | PA8200000 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | CCl2F2 |
| Molar mass | 120.91 g mol−1 |
| Appearance | Colorless gas with ether-like odor |
| Density | 1.486 g/cm³ (−29.8 °C) |
| Melting point |
-157.7 °C, 115 K, -252 °F |
| Boiling point |
-29.8 °C, 243 K, -22 °F |
| Solubility in water | 0.286 g/l at 20 °C |
| log P | 2.16 |
| Vapor pressure | 568 kPa (20 °C) |
| kH | 0.0025 mol kg-1 bar-1 |
| Hazards | |
| MSDS | External MSDS |
| EU Index | Not listed |
| Main hazards | Damaging to Earth's protective ozone |
| Flash point | Non-flammable |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Dichlorodifluoromethane (R-12), is a colorless gas, and usually sold under the brand name Freon-12, is a chlorofluorocarbon halomethane (CFC), used as a refrigerant and aerosol spray propellant. Complying with the Montreal Protocol, its manufacture was banned in the United States along with many other countries in 1994 due to concerns about damage to the ozone layer.[1] It is soluble in many organic solvents.
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The use of chlorofluorocarbons as an aerosol in medicine, for example: USP-approved salbutamol, has been phased out by the U.S. Food and Drug Administration. The use of a different propellant known as hydrofluoroalkane, or HFA, which does not harm the environment has been chosen as the replacement.[2]
R-12 was used in most refrigeration and vehicle air conditioning applications prior to 1994 before being replaced by R-134a, which has a lower ozone depletion potential. 1992-1994 was the time period in which automobile manufacturers started using R134a instead of R-12. For example, a 1993 Mercedes-Benz W140 manufactured in late 1992 came from the factory with R134a. A 1994 Chevrolet S-10 Blazer manufactured in late 1993 came from the factory with R-12. When older units leak, retrofits to (1,1,1,2-tetrafluoroethane) are recommended. Retrofits to R-134a require complete flushing and filter/dryer replacement to remove the mineral oil. Mineral oil used for R12 is not compatible with R-134a. Some oils designed for conversion to R-134a are advertised as compatible with residual R-12. New rubber hoses which are R-134a compatible may be needed for the same reason.
In systems where R-134a is not practical, an R-409A blend (60% R-22; 25% R-124; 15% R-142b) may be directly added to an R-12 system without oil change although a filter change is always recommended. R-409A usually runs on the low-pressure side of the system at 12 pounds per square inch (psi), while R-12 usually runs on the low side at 10 psi. R-409A runs at higher pressures and is less efficient but works quite well. Manufacturer recommends that existing R-12 charge should be recovered. However, as the two refrigerants are soluble in the same mineral oil there are no complications associated with mixing them.
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