Chlorofluorocarbons, commonly abbreviated as CFCs, are completely halogenated paraffin hydrocarbons. CFCs contain fluorine, carbon and chlorine. These three elements are produced from propane, ethane and methane as a volatile derivative. Freon is the DuPont brand for CFCs. Dichlorodifluoromethane is the most common representative compound of CFCs. CFCs are mainly used as propellants, solvents and as refrigerants. The production of these compounds has been gradually eliminated since CFCs are the main factors contributing to the reduction of ozone in the atmosphere. The Montreal protocol is used to gradually eliminate these compounds. Products such as hydrofluorocarbons are those that are used to replace ozone-depleting compounds.
Chronology
CFCs are compounds developed in the 1930s. CFCs have been developed as a non-toxic and non-flammable alternative to toxic substances such as ammonia. Over the years, there has been an increase in the use of CFCs. Since there is very little naturally occurring chlorine in the atmosphere, CFCs can be used to introduce more chlorine into the ozone layer. Ultraviolet radiation from the sun breaks CFCs, freeing up the chlorine molecules. These increased amounts of chlorine greatly affect the composition of the ozone layer, resulting in an increase in ultraviolet radiation that scientists have shown to be harmful to both plants and animals. The main advantage of CFCs is that they can easily be converted into liquids and vice versa.
There was a series of fatal accidents that were caused by methyl chloride that escaped from refrigerators. The incidents were recorded in the 1920s and made professionals search for an alternative compound that was less toxic than sulfur dioxide, methyl chloride and ammonia which were refrigerants. Thomas Midgley of General Motors summarized the first CFCs in 1928. He demonstrated how CFCs were safer than previously used refrigerants and how they could be used commercially in large applications. It was released with the patent of the CFC formula on 31 stDecember 1928. Kinetic Chemical Company was the first company to produce CFCs under the trade name of Freon. Du Pont and General Motors had owned this company since they were the founders. Freon was the most preferred refrigerant in the air conditioning system because it was not toxic. The non-toxicity of this compound has made public health codes to be reviewed in American cities.
Composition and production
Scientists have classified CFCs as halocarbons. Halocarbons are compounds that contain halogen atoms and carbon atoms. Each CFC molecule uses a unique numbering system for labeling. For example, the number 11 indicates the number of chlorine, hydrogen, fluorine and carbon atoms in a CFC compound. The 90 rule is the most commonly used numbering system. In this type of numbering system, 90 is added to the CFC number. The first digit of the result is the number of carbon atoms, the number of hydrogen atoms is the second digit while the last digit is the number of fluorine atoms. The expression Cl = 2 (C + 1) – H – F is used to calculate the total number of chlorine atoms (CI).
