Carbon Tetrachloride

Carbon Tetrachloride

Carbon Tetrachloride (CCl4) Carbon tetrachloride (tetrachloromethane) has been widely used as a fire extinguisher in small units (Pyrene) and as a solvent.

In contact with hot iron and oxygen, it is converted to phosgene (OCl2), a highly toxic gas.

Chlorofluorocarbons

Chlorofluorocarbons (CFCs) Chlorofluorocarbon compounds are one- and two-carbon compounds containing chlorine and fluorine. They are sometimes called by their trade name, Freons.

For many years these compounds have been widely used as refrigerants, solvents, and aerosol propellants. They were used because of their stability and their nonflammable and nontoxic properties. The most commonly used CFCs are CCl3F (CFC-11), CCl2F2 (CFC-12), CCl2FCClF2 (CFC-113), CClF2CClF2 (CFC-114), and CClF2CF3 (CFC-115). Re-cently,

CFCs have been shown to be involved in the destruction of the stratospheric ozone layer, the “ozone hole” effect, via the following reactions with ul-traviolet radiation.

Chlorofluorocarbons are also known to be greenhouse gases. Because of their role in ozone destruction and the greenhouse effect, manufacture and use of chlorofluorocarbons is being eliminated worldwide.