C2Cl2F2

C2Cl2F2, commonly known as Dichlorodifluoromethane or Freon-12, is a colorless, odorless, and non-flammable chemical compound belonging to the class of chlorofluorocarbons (CFCs). Its molecular formula is C2Cl2F2, indicating it contains two carbon atoms, two chlorine atoms, and two fluorine atoms.

CFC-12 was widely used as a refrigerant, propellant in aerosol sprays, and in foam-blowing applications due to its stability and non-toxic nature. It was favored for its effective heat transfer properties and chemical stability, as well as its non-flammability, which contributed to its widespread adoption in various industrial and consumer products.

However, scientific research in the late 20th century revealed that CFCs significantly contribute to ozone layer depletion. When released into the atmosphere, CFC-12 undergoes photodissociation by ultraviolet radiation, releasing chlorine atoms. These chlorine atoms catalytically destroy ozone molecules, resulting in thinning of the ozone layer and increased ultraviolet radiation reaching the Earth's surface. The recognition of these environmental impacts led to international regulation under the Montreal Protocol of 1987, which phased out the production and use of many CFCs, including CFC-12.

Today, the use of CFC-12 has been largely replaced by more environmentally friendly substances such as hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs), although some stockpiles and residual applications persist. Proper disposal and recycling of CFCs are crucial to minimize their environmental and atmospheric impact. Their study remains important for understanding ozone chemistry and guiding sustainable practices in refrigeration and other industries.