Chloroflurocarbons, also known as CFCs, are fully halogenated paraffin hydrocarbons that contain only Carbon, Chlorine, and Fluorine. They are manufactured as a volatile derivative of Methane, Ethane, and Propane. (Source from WikiPedia.) You may know CFC refrigerants by their most common name, Freon. For those of you who do not know Freon is a registered brand name from the DuPont corporation.
Popular CFC Refrigerants
- R-12, or Dichlorodifluromethane, is the most popular CFC refrigerant of them all.
- R-11, or Trichlorofluromethane, is a lesser known CFC refrigerant.
- R-502, or a blended mixture of R-22 and R-115. Ratio of 48.8% of R-22 and 51.20% of R-115.
Other CFC Refrigerants
More Information on CFCs
Most people think that General Motors and DuPont were the ones who invented CFC refrigerants but those people would be wrong. In fact it was a Belgian scientist known as Frédéric Swarts who led the way in synthesizing CFCs in the 1890’s. What General Motors and DuPont did was improve and innovate on Swarts’ process.
If we then fast forward nearly thirty year later we have Thomas Midgley, Jr. building off of Frédéric Swarts work. Thomas Midgley was part of a team assembled by Charles Kettering, the Vice President of General Motor’s Research Corporation at the time. This team was built to develop an alternative compound to the dangerous refrigerants that were on the market.
In the 1920’s air conditioning and refrigerated units were using refrigerants such as Ammonia, Chloromethane, Propane ,and Sulfur Dioxide. These refrigerants worked, more or less, but they were toxic. If a leak was sprung then tragedy could occur, and that was on the tame side. Other refrigerants used such as Propane, were flammable, or even explosive in the right circumstances. It was expensive owning a refrigerator back then and it was also a gamble for you and your family’s safety. There had to be a better way.
After some debate the GM team narrowed their focus on Alkyl Halides. These chemical agents were known to be highly volatile which is a primary requirement for a refrigerant compound. The more prone and easy to change an agent the more successful it will be as a refrigerant. Remember, refrigeration is all about changing states.
The team settled on a concept of incorporating the chemical Fluorine into a Hydrocarbon. Hydrocarbons are naturally occurring elements such as Propane, Methane, Isobutane, or Propylene. The team believed that this new refrigerant would be non-toxic due to the stability of the Carbon-Fluorine bond. This bond would prevent the release of the Hydrogen Fluoride combination and also prevent any other breakdowns from occurring. After some time the team was successful and they synthesized Dichlorodifluromethane, or R-12 Freon.
The synthesization of R-12 Freon was a revolution in the refrigeration world. There was finally a refrigerant that was safe, non-flammable, and non-toxic. On top of that it was efficient and operated at lower pressures then the other main refrigerant competitor, R-744. There were numerous CFC refrigerants used during this time including R-11, R-12, and in 1935 a new HCFC refrigerant known as R-22. With the introduction of all of these new refrigerants the use of refrigeration and air-conditioning really began to pick up over the next twenty to thirty years.
I like to think of CFC refrigerants as the grandfathers of the industry. Sure, there were other types out there like we discussed earlier but they never really caught on like CFCs and later HCFCs did. CFC’s changed everything and helped make air-conditioning and refrigeration affordable to the average man. Of course though, like all good things it had to come to an end.
By the 1960’s and 70’s CFCs and HCFCs were everywhere in the United States and across the globe. They were in your grocery stores, your homes, your factories, everywhere. It was in the 1980’s that a problem was discovered. Two American scientists, Mario Molina and Shepwood Rowland, from a California university were the first to notice Chlorine’s effect on the atmosphere. (Remember now folks, all of these CFCs and HCFCs contain Chlorine.)
These two scientists found that when a CFC refrigerant was exposed to ultra-violet irradiation that the Chlorine atom would detach itself from the CFC molecules. The remaining residue is oxidized resulting in the creation of a Chlorine oxidized molecule and a new residue. The Chlorine atom and Chlorine oxidized molecule move their way up to the stratosphere. Within the stratosphere there is a layer called the Ozone layer. This Ozone layer protects the Earth from ultra-violet rays and irradiation. What these scientists found out is that all of this Chlorine from CFC and HCFC refrigerants was working it’s way to the stratosphere. When it reached the stratosphere the Chlorine began to attack and weaken the Ozone layer.
Over decades of using CFCs and HCFC refrierants Chlorine began to accumulate in the stratosphere and overtime a hole began to form in the Ozone layer. Now, I say hole but this wasn’t a hole per-say. Instead, there was a weakening of strength in the layer. So, while there was not a hole the thickness of the Ozone was decreasing and decreasing rapidly thanks to the CFC and HCFC refrigerants.
The Ozone prevents harmful UVB wavelengths of ultra-violet light from passing through the Earth’s atmosphere. Without it, or with a weakened version of it, a variety of bad things could happen. Some of these include a much higher increased chance of Skin Cancer, more severe sunburns, more chances of cataracts, and a whole host of other problems.
After discovering the weakening of the Ozone layer nations banded together in what is seen as one of the greatest and most effective treaty’s every made. In 1986-1987 the Montreal Protocol was created and signed by over one-hundred nations across the world. This Protocol was an international treaty designed to protect the Ozone layer and to completely phase out the chemicals responsible for the weakening of the Ozone. The treaty went into effect in 1989.
Soon after that date marked the beginning of the end for CFC and HCFC refrigerants across the globe. The industrialized countries, like America, began to phase out the refrigerants first. R-12 was phased out in the early 1990’s along with all of the rest of the CFC refrigerants. The HCFC refrigerants such as R-22 or even R-502 were given a bit more time. Heck, R-22’s true phase out didn’t even begin until 2010.
Out with the old and in with the new, so they say. The refrigerants that were proposed to replace CFCs and HCFCs were known as HFCs, or Hydroflurocarbons. These refrigerants contained no Chlorine so there was no chance of them hurting the Ozone layer. Some of these refrigerants include popular refrigerants today known as R-134a, R-404A, and R-410A. But, now these refrigerants are under fire for their increase to Global Warming. No one knows for certain what the future of refrigerants will be. Will we ever find that perfect refrigerant that is efficient, safe, non-flammable, and that is safe for the environment? Time will only tell.