Chlorotrifluoromethane, R-13, CFC-13, or Freon 13, is a non-flammable, non-corrosive, nontoxic chlorofluorocarbon (CFC) and also a mixed halomethane. It is a man-made substance used primarily as a refrigerant. When released into the environment, CFC-13 has a high ozone depletion potential, and long atmospheric lifetime.[2] Only a few other greenhouse gases surpass CFC-13 in global warming potential (GWP).[3]: 2 The IPCC AR5 reported that CFC-13's atmospheric lifetime was 640 years.[4]
CFC-13—like all chlorofluorocarbon compounds—contains atoms of carbon (C), chlorine (Cl), and fluorine (F).[5][6]
It can be prepared by reacting carbon tetrachloride with hydrogen fluoride in the presence of a catalytic amount of antimony pentachloride:
This reaction can also produce trichlorofluoromethane (CCl3F), dichlorodifluoromethane (CCl2F2) and tetrafluoromethane (CF4).[7]
Following the unanimous ratification of the 1987 Montreal Protocol—in response to concerns about the role of concentrations of chlorofluorocarbons (CFCs) in ozone layer-depletion in the stratosphere—a process was put into place to gradually phase out and replace CFC-13 and all the other CFCs.[8] Research in the 1980s said that these man-made CFC compound compounds had opened a hole in ozone layer in the upper atmosphere or stratosphere that protects life on earth from UV radiation.[5]
CFC-13's ozone depletion potential (ODP) is high— 1[9] (CCl3F = 1)—it is categorized as a Class I in the IPCC's list of ozone-depleting substances.[9] CFC-13's radiative efficiency is high which results in a high global warming potential (GWPs) of 13 900 GWP-100 yr that is "surpassed by very few other greenhouse gases."[3] It is categorized as a Class I in the list of ozone-depleting Substances.[9]: 2
Starting in the 2010s, despite a global ban on the production of CFCs, five of these ozone-damaging emissions were on the rise.[5]
The atmospheric abundance of CFC-13 rose from 3.0 parts per trillion (ppt) in year 2010 to 3.3 ppt in year 2020 based on analysis of air samples gathered from sites around the world.[10] Contrary to the Montreal Protocol, the atmospheric emissions of CFC-13 and four other chlorofluorocarbons (CFCs), increased between 2010 and 2020.[11]
As of 2023, the drivers behind the increase in CFC-13 and CFC-112a emissions were not certain.[11]
The IPCC AR5 reported that CFC-13's Atmospheric lifetime was 640 years.[12]