Refrigerants for the 21st Century
6. Early Fluorinated Refrigerants

After successful introduction of CFC-12 for mechanical refrigeration, other fluorocarbons were prepared and found to have commercial utility. We list some of these below.  You can see how the availability of these chlorofluorocarbons led to a wide range of specialized refrigeration, aerosol and other commercial uses.  

Chemical Composition Designation Boiling Point
@760 torr
Applications
CF2Cl2 CFC-12 -29.8oC Refrigeration, auto
air conditioning, aerosols, polymer
foam blowing
CFCl3 CFC-11 23.8oC Air conditioning, water chillers,
aerosols, foam blowing, solvent
CHF2Cl HCFC-22 -40.8oC Low temperature refrigeration, central and window
air conditioners, "Teflon" raw material
CF2ClCFCl2 CFC-113 47.6oC Foam blowing, solvent
CF2ClCF2Cl CFC-114 3.8oC Refrigeration, aerosols
CF3CF2Cl CFC-115 -38.7oC Supermarket open-case refrigeration

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If we review these applications for the CFC's, it's not hard to see that many CFC's would be emitted to the atmosphere during use - aerosol, foam blowing, solvent. While mechanical refrigerators are designed not to leak refrigerant (though they are not hermetically sealed), eventually they will release their contents. Auto air conditioners have long been subject to leakage owing to vibration and the need to use rubber hoses for connections. The practice of "topping off" the auto refrigerant has become common, even by the car owners.

Therefore, it should not have come as a surprise when British philosopher and chemist Prof. James Lovelock  reported in 1973 that he detected a build-up of CFC-11 and CFC-12 in the atmosphere.  His results stemmed from his invention of extraordinarily sensitive electron capture devices (ECD) that enabled him to detect the presence of compounds like the chlorofluorocarbons at the parts per billion level in gases.  Prof. Lovelock's findings might at first raise only limited concern until we recall the chemical stability of the chlorofluorocarbons.

You can keep abreast of chlorofluorocarbon developments by searching one or more of the search engines.  From AltaVista you will find these references.


Concept Map for this ChemCase

Fluorocarbon Alternatives
Case Study: Ozone Layer Degradation

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Principal Investigator Laurence Peterson; Project Director Matthew Hermes;
Author of this module William Gumprecht.