text: Worldwide production of R-22 in 2008 was about 800Gg per year, up from about 450Gg per year in 1998, with most production in developing countries.  R-22 use is being phased out in developing countries, where it is largely used for air conditioning applications. Air conditioning sales are growing 20% annually in India and China.
  R-22 is prepared from chloroform:
  :HCCl + 2 HF → HCFCl + 2 HCl
  An important application of R-22 is as a precursor to tetrafluoroethylene.  This conversion involves pyrolysis to give difluorocarbene, which dimerizes:
  :2 CHClF → CF + 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.