CC12F2 Dichlorodifluoromethane

In a dump site, you find an old 3-liter pressure bottle with a pressure gauge that indicates a pressure of 2.7 bar. The temperature is 10°C. From the label you can see that the bottle contains Freon 12 (i.e., dichlorodifluoromethane, CC12F2). You wonder how much Freon 12 is still left in bottle. Try to answer this question. In the CRC Handbook of Chemistry and Physics (Lide, 1995) you find the following data on CC12F2 ... 

Estimate the molar volume Vt of dichlorodifluoromethane CC12F2 (also called freon-12 or CFC-12) (a) from its liquid density and (b) with the element contribution method by Fuller (Table 18.2). 

Dichlorodifluoromethane (CC12F2, CFC-12) enters a small lake (surface area =(/ /40 = 2 x 104 m2, maximum depth zm = 10 m) from the atmosphere by air-water... 

Halogenated Hydrocarbons. A few halogenated hydrocarbons were studied by the usual procedure, using mixtures in air over the platinum filament. Neither dichlorodifluoromethane (CC12F2) nor 1,1-dichloro-ethene yielded a measurable ion current at temperatures up to 900°C. 1,1,1-Trichloroethane yielded a modest ion current, but the results were erratic and not reproducible. There was some indication that the halogen compounds changed the behavior of the filament. Consequently, no further experiments with halogenated compounds were conducted. This erratic behavior was in contrast with the very reproducible results with hydrocarbons. 

Owing to the extreme chemical activity of fluorine, the chief uses of this element arise in connection with the production of its compounds. Thus, sodium fluoride is commonly used as a flux, as an insecticide, and as a wood preservative. Ammonium fluoride is sometimes used as a disinfectant. The compound dichlorodifluoromethane (CC12F2) is used as an insecticide propellent and is an important commercial refrigerant (Freon), particularly well suited for use in domestic refrigeration units. 

In 1928, Thomas Midgley invented the first CFC compound. Because they were useful but safe, they were referred to as miracle compounds. In particular, dichlorodifluoromethane, CC12F2, also known as Freon, was discovered to be an efficient refrigerant. 

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