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Re: The "numbering system" section I was a chemist at the DuPont R&D facility in NJ where the Freons were manufactured. The mathematical system used was to represent the formula as #C, #H, and #F as a three digit number and then subtract 90. So, CCl3F would be represented as 101 which would equate to F-11 after subtracting 90.
The system used in the article with the "plus 1" and "minus 1" results in the same designation, but it seems confusing and would certainly be harder to remember. Dcobranchi ( talk) 13:53, 7 May 2010 (UTC)
The introduction states that CFCs contain C, F and Cl. For me it means that they do not contain hydrogen. In this case, however, HCFCs are not a subclass of CFCs (as it is stated in the second sentence), but they are an entirely separate class (without an intersection with CFCs). I do not know which statement is correct, but it should be clarified and the text corrected accordingly. Szaszicska ( talk) 17:08, 1 August 2010 (UTC)
HFCs are super pollutants used in fridges, air conditioners and foam insulation. Thousands of times more potent than carbon dioxide, they could account for 19% of greenhouse gas emissions by 2050 if their manufacture continues unchecked.
— Megan Darby
71.82.112.140 ( talk) 15:25, 8 August 2014 (UTC)Unfortunately, in many cases CFCs were replaced by HFCs, which do not damage the ozone layer but are similarly effective at heating up the planet.
Although Hydrochlorofluorocarbons and HCFC both redirect to the top of the article, one needs to scroll down until Chlorofluorocarbon § Classes of compounds, nomenclature in order to know that it stands for Hydro-chlorofluorocarbons. The lead sentence, however, implicitly excludes Hydro-chlorofluorocarbons from the article. I came to this article from Pentafluoropropane where it says: "Unlike CFC and HCFC...". Because both links point to "Chlorofluorocarbon" it is rather confusing. I think the lead should mention HCFC, as it appears in the article. At least the first instance of HCFC should mention "Hydro-chlorofluorocarbons" (not the case). It would also be helpful to know whether it should be written with a hyphen "Hydro-chlorofluorocarbons" (as in the article) or without a hyphen (as in the redirect Hydrochlorofluorocarbons. Rfassbind – talk 14:45, 17 July 2016 (UTC)
Seems to me a side effect of the way chemists discuss organic compounds. In diagrams, hydrogens are assumed, and not drawn is. Also, all these compounds are halogenated hydrocarbons, that is, replacing hydrogen atoms with halogen atoms. inside the lab, there is not a big distinction on how many hydrogen atoms are left. But yes, the presence of H helps shorten the atmospheric lifetime, which is important outside the chemistry lab. Gah4 ( talk) 22:42, 29 September 2016 (UTC)
The opening says " A chlorofluorocarbon (CFC) is an organic compound that contains carbon, chlorine, and fluorine, produced as a volatile derivative of methane and ethane. A common subclass is the hydrochlorofluorocarbons (HCFCs), which contain hydrogen, as well. They are also commonly known by the DuPont trade name Freon." Does the bold 'they' mean that CFC's are also known as Freon, or that HCFC's are? Smash bros master ( talk) 01:46, 25 May 2011 (UTC)
The section with alternative replacements lists replacements for materials that are hazardous for the ozone layer. HFC 23 was listed as such a substitute for bad HCFC refrigerants. However, the article for HCFC 23 lists it as a substantial greenhouse gas contributor. The recommendation is not cited, so I presume the contributor listed it this way due to what I presume to be its negligible effect on the ozone layer. The section following this mentions the global warming hazard. Maybe what is needed in the alternatives section is emphasis on replacement from the POV of ozone dangers, not replacement in view of the totality of environmental risks. I have not researched it, so I don't know the answer. If you are reading this, the listing is still there and a reasonable amount of time has elapsed with no one defending this listing, I recommended modifying or clarifying the section or if an error was made, deleting the entry. J JMesserly ( talk) 13:20, 11 May 2012 (UTC)
The article claims that CFCs are being replaced by HFCs, hydrocarbons, and CO2, because CFCs contribute to ozone depletion in the upper atmosphere. This claim implies that HFCs are being used as a solution to the problem of ozone depletion caused by CFCs. However, this is not necessarily the case. It should be noted that:
if HFC growth continues on the current trajectory, the increase in HFC emissions is projected to offset much of the climate benefit achieved by phasing out ozone-depleting substances.
— EPA
71.82.112.140 ( talk) 15:03, 8 August 2014 (UTC)
What order are the entries in the table? I could expect alphabetically, or in increasing boiling point, but it doesn't seem one of those. Gah4 ( talk) 22:43, 29 September 2016 (UTC)
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I recall that approximately twenty years ago the concentration of chlorofuorocarbons in the 'ozone layer' was 3-4 parts per billion, that is 3 to 4 cubic millimetres per thousand cubic kilometres. What is the concentration now? — Preceding unsigned comment added by 1.129.96.19 ( talk) 20:22, 2 January 2017 (UTC)
Yeas, thanks for the correction. I have just viewed www.theozonehole.com/cfc.htm that indicates that the chlorofluorocarbon concentration peaked at 500 parts per trillion, that is 5 parts per 10,000,000,000. Hope my maths is good and that I have correctly converted the figure to 5cu.mm per 10,000 cu. Klms. — Preceding unsigned comment added by 1.129.96.19 ( talk) 20:49, 2 January 2017 (UTC)
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The article says: The most common representative is dichlorodifluoromethane (R-12 or Freon-12). I wonder if this is still true? I am not sure that it ever was, as R-11 and some others are more common in industrial settings. (That is, if weighted by actual weight.) But R134a has been common for many years now, such that, at least for consumer use, it should be more common. Gah4 ( talk) 04:59, 15 October 2018 (UTC)
It seems that HCFC redirects here. I suppose that isn't bad, but I might have thought they deserved their own article. I was about to revert the recent change, but with the redirect, they are needed. Gah4 ( talk) 23:06, 23 May 2019 (UTC)
How about unsaturated chlorofluorocarbons which most are derivatives of alkenes (e.g. ethylene), alkynes (e.g. acetylene), or dienes (e.g. butadiene)? If found, they are often highly toxic as hydrogen cyanide! 2405:9800:BA31:F6:1135:D0BB:5A4E:577 ( talk) 02:36, 10 September 2021 (UTC)
Why are CFC and HCFC molecules both described in the same article? 137.59.221.36 ( talk)\\~~\\\ 137.59.221.36 ( talk) 10:08, 30 December 2021 (UTC)
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Re: The "numbering system" section I was a chemist at the DuPont R&D facility in NJ where the Freons were manufactured. The mathematical system used was to represent the formula as #C, #H, and #F as a three digit number and then subtract 90. So, CCl3F would be represented as 101 which would equate to F-11 after subtracting 90.
The system used in the article with the "plus 1" and "minus 1" results in the same designation, but it seems confusing and would certainly be harder to remember. Dcobranchi ( talk) 13:53, 7 May 2010 (UTC)
The introduction states that CFCs contain C, F and Cl. For me it means that they do not contain hydrogen. In this case, however, HCFCs are not a subclass of CFCs (as it is stated in the second sentence), but they are an entirely separate class (without an intersection with CFCs). I do not know which statement is correct, but it should be clarified and the text corrected accordingly. Szaszicska ( talk) 17:08, 1 August 2010 (UTC)
HFCs are super pollutants used in fridges, air conditioners and foam insulation. Thousands of times more potent than carbon dioxide, they could account for 19% of greenhouse gas emissions by 2050 if their manufacture continues unchecked.
— Megan Darby
71.82.112.140 ( talk) 15:25, 8 August 2014 (UTC)Unfortunately, in many cases CFCs were replaced by HFCs, which do not damage the ozone layer but are similarly effective at heating up the planet.
Although Hydrochlorofluorocarbons and HCFC both redirect to the top of the article, one needs to scroll down until Chlorofluorocarbon § Classes of compounds, nomenclature in order to know that it stands for Hydro-chlorofluorocarbons. The lead sentence, however, implicitly excludes Hydro-chlorofluorocarbons from the article. I came to this article from Pentafluoropropane where it says: "Unlike CFC and HCFC...". Because both links point to "Chlorofluorocarbon" it is rather confusing. I think the lead should mention HCFC, as it appears in the article. At least the first instance of HCFC should mention "Hydro-chlorofluorocarbons" (not the case). It would also be helpful to know whether it should be written with a hyphen "Hydro-chlorofluorocarbons" (as in the article) or without a hyphen (as in the redirect Hydrochlorofluorocarbons. Rfassbind – talk 14:45, 17 July 2016 (UTC)
Seems to me a side effect of the way chemists discuss organic compounds. In diagrams, hydrogens are assumed, and not drawn is. Also, all these compounds are halogenated hydrocarbons, that is, replacing hydrogen atoms with halogen atoms. inside the lab, there is not a big distinction on how many hydrogen atoms are left. But yes, the presence of H helps shorten the atmospheric lifetime, which is important outside the chemistry lab. Gah4 ( talk) 22:42, 29 September 2016 (UTC)
The opening says " A chlorofluorocarbon (CFC) is an organic compound that contains carbon, chlorine, and fluorine, produced as a volatile derivative of methane and ethane. A common subclass is the hydrochlorofluorocarbons (HCFCs), which contain hydrogen, as well. They are also commonly known by the DuPont trade name Freon." Does the bold 'they' mean that CFC's are also known as Freon, or that HCFC's are? Smash bros master ( talk) 01:46, 25 May 2011 (UTC)
The section with alternative replacements lists replacements for materials that are hazardous for the ozone layer. HFC 23 was listed as such a substitute for bad HCFC refrigerants. However, the article for HCFC 23 lists it as a substantial greenhouse gas contributor. The recommendation is not cited, so I presume the contributor listed it this way due to what I presume to be its negligible effect on the ozone layer. The section following this mentions the global warming hazard. Maybe what is needed in the alternatives section is emphasis on replacement from the POV of ozone dangers, not replacement in view of the totality of environmental risks. I have not researched it, so I don't know the answer. If you are reading this, the listing is still there and a reasonable amount of time has elapsed with no one defending this listing, I recommended modifying or clarifying the section or if an error was made, deleting the entry. J JMesserly ( talk) 13:20, 11 May 2012 (UTC)
The article claims that CFCs are being replaced by HFCs, hydrocarbons, and CO2, because CFCs contribute to ozone depletion in the upper atmosphere. This claim implies that HFCs are being used as a solution to the problem of ozone depletion caused by CFCs. However, this is not necessarily the case. It should be noted that:
if HFC growth continues on the current trajectory, the increase in HFC emissions is projected to offset much of the climate benefit achieved by phasing out ozone-depleting substances.
— EPA
71.82.112.140 ( talk) 15:03, 8 August 2014 (UTC)
What order are the entries in the table? I could expect alphabetically, or in increasing boiling point, but it doesn't seem one of those. Gah4 ( talk) 22:43, 29 September 2016 (UTC)
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I recall that approximately twenty years ago the concentration of chlorofuorocarbons in the 'ozone layer' was 3-4 parts per billion, that is 3 to 4 cubic millimetres per thousand cubic kilometres. What is the concentration now? — Preceding unsigned comment added by 1.129.96.19 ( talk) 20:22, 2 January 2017 (UTC)
Yeas, thanks for the correction. I have just viewed www.theozonehole.com/cfc.htm that indicates that the chlorofluorocarbon concentration peaked at 500 parts per trillion, that is 5 parts per 10,000,000,000. Hope my maths is good and that I have correctly converted the figure to 5cu.mm per 10,000 cu. Klms. — Preceding unsigned comment added by 1.129.96.19 ( talk) 20:49, 2 January 2017 (UTC)
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The article says: The most common representative is dichlorodifluoromethane (R-12 or Freon-12). I wonder if this is still true? I am not sure that it ever was, as R-11 and some others are more common in industrial settings. (That is, if weighted by actual weight.) But R134a has been common for many years now, such that, at least for consumer use, it should be more common. Gah4 ( talk) 04:59, 15 October 2018 (UTC)
It seems that HCFC redirects here. I suppose that isn't bad, but I might have thought they deserved their own article. I was about to revert the recent change, but with the redirect, they are needed. Gah4 ( talk) 23:06, 23 May 2019 (UTC)
How about unsaturated chlorofluorocarbons which most are derivatives of alkenes (e.g. ethylene), alkynes (e.g. acetylene), or dienes (e.g. butadiene)? If found, they are often highly toxic as hydrogen cyanide! 2405:9800:BA31:F6:1135:D0BB:5A4E:577 ( talk) 02:36, 10 September 2021 (UTC)
Why are CFC and HCFC molecules both described in the same article? 137.59.221.36 ( talk)\\~~\\\ 137.59.221.36 ( talk) 10:08, 30 December 2021 (UTC)