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|Section2= |Section3= |Section4= }} Chlorodifluoromethane or difluoromonochloromethane is a hydrochlorofluorocarbon (HCFC). This colorless gas is better known as HCFC-22, or R-22. It is commonly used as a propellant and refrigerant. These applications are being phased out in developed countries due to the compound's ozone depletion potential (ODP) and high global warming potential (GWP), although global use of R-22 continues to increase because of high demand in developing countries. R-22 is a versatile intermediate in industrial organofluorine chemistry, e.g. as a precursor to tetrafluoroethylene. R-22 cylinders are colored light green.〔()〕 ==Production and current applications== Worldwide production of R-22 in 2008 was about 800 Gg per year, up from about 450 Gg per year in 1998, with most production in developing countries.〔 R-22 use is increasing in developing countries, largely for air conditioning applications. Air conditioning sales are growing 20% annually in India and China. R-22 is prepared from chloroform: :HCCl3 + 2 HF → HCF2Cl + 2 HCl An important application of R-22 is as a precursor to tetrafluoroethylene. This conversion involves pyrolysis to give difluorocarbene, which dimerizes:〔Günter Siegemund, Werner Schwertfeger, Andrew Feiring, Bruce Sart, Fred Behr, Herward Vogel, Blaine McKusick "Fluorine Compounds, Organic" Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. 〕 :2 CHClF2 → C2F4 + 2 HCl The compound also yields difluorocarbene upon treatment with strong base and is used in the laboratory as a source of this reactive intermediate. The pyrolysis of R-22 in the presence of chlorofluoromethane gives hexafluorobenzene. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「chlorodifluoromethane」の詳細全文を読む スポンサード リンク
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