Identification

• Freon is DuPont's trade name for dichlorodifluoromethane. Dichlorodifluoromethane is an inert gas that is used as a refrigerant. Dichlorodifluoromethane is also called chlorofluorocarbon, or CFC. Freon is a nonflammable and colorless liquid that does not occur naturally and must be produced. It contains carbon atoms, fluorine atoms, hydrogen atoms and chlorine in varying amounts.
  
  

Function

• Freon has been used as a refrigerant in freezers, refrigerators and air conditioners. Freon has also been used in fire suppressant systems, as a cold-cleaning solvent, a vapor degreasing solvent, a solvent for machinery manufacture and repair and in metal degreasing. Freon has also been used by mass spectroscopists to help locate mass spectrometer vacuum leaks.
  
  

Types

• There are various types of freon, in that the formulas may vary between compounds. A naming system was developed by DuPont to differentiate between the formulas. This is reflected in a number that is attached to the word freon. For example, freon 12 was the refrigerant in the first refrigerators. The numbers reflect the number of carbon atoms, hydrogen atoms, fluorine atoms and chlorine in that formula.
  
  

History

• Refrigerators began replacing iceboxes in the United States with the introduction of Kelvinator and Servel models in 1916. If leaked, the refrigerants used in the early refrigerators could be fatal. Three companies--Frigidaire, General Motors and DuPont--worked to develop a safer refrigerant. Thomas Midgley, Jr. and Charles Franklin Kettering invented freon in 1928. Midgley was also the inventor of ethyl gasoline. Kettering held over 300 patents and was the head of research for General Motors for 27 years.
  
  

Warning

• Freon, or dichlorodifluoromethane, negatively impacts the environment. It is a significant factor in depleting the ozone level. Production of dichlorodifluoromethane is banned in the United States, and use of the material is regulated. The Clean Air Act prohibits venting freon when servicing or disposing of refrigeration or air conditioning equipment. The freon must be removed from the appliances prior to disposing. Handling of freon requires a certified technician licensed with the EPA.