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Topic: Chlorofluorocarbons

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In the News (Sun 16 Jun 19)

  Haloalkane - Wikipedia, the free encyclopedia
Chlorofluorocarbons (CFC) are haloalkanes with both chlorine and fluorine.
Chlorofluorocarbons (CFC) were developed by the American engineer Thomas Midgley in 1928 as a replacement for ammonia (NH chloromethane (CH Cl), and sulfur dioxide (SO), toxic but in common use at the time as refrigerants.
There is concern that halons are being broken down in the atmosphere to bromine, which reacts with ozone, leading to depletion of the ozone layer (this is similar to the case of chlorofluorocarbons such as freon).
en.wikipedia.org /wiki/Chlorofluorocarbon   (3244 words)

 Chlorofluorocarbons, fully halogenated (EHC 113, 1990)
Throughout this monograph, percentages of chlorofluorocarbons in air are expressed as the volume of chlorofluorocarbon divided by the volume of air.
Release of chlorofluorocarbons into the global environment during use, disposal of wastes, transport, and storage are an increasing concern because of the potential impact such uncontrolled releases may have on the future health of mankind, mainly through the depletion of stratospheric ozone.
Chlorofluorocarbons are usually characterized by high vapour pressure (low boiling point) and density and low viscosity, surface tension, refractive index, and solu- bility in water.
www.inchem.org /documents/ehc/ehc/ehc113.htm   (14152 words)

 Halocarbons and the Stratospheric Ozone Layer (Science Tracer Bullet - Science Reference Services, Library of Congress)
Chlorofluorocarbons are compounds, similar to hydrocarbons, in which most, or all, of the hydrogen atoms have been replaced by various combinations of fluorine and chlorine atoms.
Chlorofluorocarbon effects and regulations: hearing before the Subcommittee on the Upper Atmosphere of the Committee on Aeronautical and Space Sciences, United States Senate, Ninety-fourth Congress, second session, December 15, 1976.
----- Chlorofluorocarbons and the depletion of stratospheric ozone.
www.lcweb.loc.gov /rr/scitech/tracer-bullets/halocarbonstb.html   (1081 words)

 PRODUCT MATRIX - Chlorofluorocarbons   (Site not responding. Last check: 2007-10-07)
Chlorofluorocarbons are highly volatile compounds, contributing to air pollution.
Chlorofluorocarbons are implicated in two major threats to the global environment: the greenhouse effect and the reduction of the ozone layer.
As the chlorofluorocarbons break down, they release a chlorine atom which is capable of destroying tens of thousands of ozone molecules before being washed out of the atmosphere.
hutch.momsmakemore.com /house1/chlorofl.htm   (604 words)

 Production and Uses of CFC's   (Site not responding. Last check: 2007-10-07)
The invention of chlorofluorocarbons (CFCs) in the late 1920s and early 1930s stemmed from the call for safer alternatives to the sulfur dioxide and ammonia refrigerants used at the time.
Chlorofluorocarbons were chosen for their safety and for their advantageous chemical properties.
Of the 682 million kilograms of chlorofluorocarbons consumed globally during 1991, the DuPont Corporation estimates the use for various applications as follows: 32 percent for refrigerants, 28 percent for blowing agents, 20 percent for cleaning agents, and 18 percent for propellants.
www.ciesin.org /TG/OZ/prodcfcs.html   (469 words)

 EPA History - Statement at International Meeting on Chlorofluorocarbons   (Site not responding. Last check: 2007-10-07)
In combination with effects predicted to occur as a result of increased combustion of fossil fuels, continued release of chlorofluorocarbons at current levels could also contribute to a potentially dangerous warming of the earth's atmosphere, altering climate and possible even partially melting the polar icecaps.
Sweden and Norway have banned the use of chlorofluorocarbons as aerosol propellants.
Canada's ban on chlorofluorocarbon propellants will be effective this May. And at this conference, Canada welcomed the newest U.S. initiative and agreed to consider taking similar steps.
www.epa.gov /history1/topics/ozone/05.htm   (601 words)

 FDA Consumer: Chlorofluorocarbons and the incredible shrinking ozone
Chlorofluorocarbons, or CFCs, have been at the center of an intense debate for nearly 15 years over scientific uncertainties and the conflict between environmental protection and economic interests.
Chlorofluorocarbons are a group of chemicals discovered around 1930 that contain varying numbers of chlorine, fluorine, carbon and, sometimes, bromine atoms.
The original debate over chlorofluorocarbons was set off in the early 1970s by chemists F. Sherwood Rowland and Mario Molina, both then with the University of California at Irvine.
www.findarticles.com /p/articles/mi_m1370/is_n10_v21/ai_6245243   (1344 words)

 Chlorofluorocarbons, partially halogenated (methane derivatives) (EHC 126, 1991)
Chlorofluorocarbons are very stable compounds, which remain intact in the air, releasing chlorine only when they reach the stratosphere.
Chlorofluorocarbons are numbered as follows: the first digit = number of C atoms minus 1 for methane derivatives it is therefore zero); second digit = number of H atoms plus 1; third digit = number of F atoms.
The ODP is defined as the calculated ozone depletion due to the emission of a unit mass of the chlorofluorocarbon divided by the ozone depletion calculated to be due to the emission of CFC 11; calculations are based on steady- state conditions (UNEP/WMO, 1989).
www.inchem.org /documents/ehc/ehc/ehc126.htm   (13854 words)

 Search: chlorofluorocarbons - FOX News   (Site not responding. Last check: 2007-10-07)
Chlorofluorocarbons (CFCs) are nontoxic, nonflammable chemicals containing atoms of carbon, chlorine, and...
Chlorofluorocarbons (CFCs) are a family of non-toxic, inert chemical compounds that contain chlorine, fluorine and carbon bound tightly to form inert molecules.
Chlorofluorocarbons (CFCs) are a class of man-made chemicals known by such tradenames as "Freon," "Genetron," and "Isotron."...
search.foxnews.com /info.foxnws/redirs_all.htm?pgtarg=wbsdogpile&qcat=web&qkw=chlorofluorocarbons   (457 words)

 Process for preparing chlorofluorocarbons via an in situ generated activated aluminum trihalide catalyst and products ...   (Site not responding. Last check: 2007-10-07)
A process for isomerizing a chlorofluorocarbon of the formula: CClFYCClFX wherein X and Y are independently selected from chlorine and fluorine provided that X is not --Cl when Y is --F to the compound of the formula: CCl.sub.2 YCF.sub.2 X The process comprises contacting the chlorofluorocarbon with an activated aluminum trihalide catalyst.
The process of claim 8 wherein said chlorofluorocarbon is contacted with said aluminum trichloride and said metal for a time sufficient for said chlorofluorocarbon to be less than 45,000 ppm.
The introduction of the chlorofluorocarbon of formula (I), anhydrous aluminum trichloride and metal to the reaction vessel generates in situ an aluminum trihalide catalyst to which the high yields of the desired isomer in the product mixture is attributed.
www.freepatentsonline.com /5017732.html   (3991 words)

 Chlorofluorocarbons - CFC's (CFC), any of several organic compounds composed of carbon, fluorine, chlorine, and ...   (Site not responding. Last check: 2007-10-07)
Chlorofluorocarbons - CFC's (CFC), any of several organic compounds composed of carbon, fluorine, chlorine, and hydrogen.
These halogenated hydrocarbons, notably trichlorofluoromethane (CFC-11, or F-11) and dichlorodifluoromethane (CFC-12, or F-12) Freon A (trademark), any of several chlorofluorocarbons (CFCs) that are used in commerce and industry.
A (trademark), any of several chlorofluorocarbons (CFCs) that are used in commerce and industry.
www.c-f-c.com /supportdocs/cfcs.htm   (479 words)

 CFCs and Ozone Depletion   (Site not responding. Last check: 2007-10-07)
Chlorofluorocarbons (CFCs), along with other chlorine- and bromine-containing compounds, have been implicated in the accelerated depletion of ozone in the Earth's stratosphere.
Production and Use of Chlorofluorocarbons experienced nearly uninterrupted growth as demand for products requiring their use continued to rise.
A primary objective for researchers in addressing this issue has been analysis of Measurements and Trends in Ozone and Chlorofluorocarbon Levels.
www.ciesin.org /TG/OZ/cfcozn.html   (459 words)

 VA Aquifer Susceptibility-Chlorofluorocarbons
Chlorofluorocarbons (CFCs) are stable synthetic organic compounds that were first manufactured in the 1930's and used as refrigerants, aerosol propellants, cleaning agents, solvents, and
The apparent age is simply the difference between the date of sample collection and the estimated date the tracer entered the ground-water system.
Plummer, L.N., and Busenberg, Eurybiades, 2000, Chlorofluorocarbons, in Cook, P.G., and Herczeg, Andrew, eds., Environmental tracers in subsurface hydrology: Kluwer Academic Publishers, p.
va.water.usgs.gov /va123/3age-A.html   (292 words)

 Dáil Éireann - Volume 386 - 07 February, 1989 - Ceisteanna—Questions. Oral Answers. - Use of ...
The control of the production and consumption of chlorofluorocarbons in the interests of protecting the ozone layer can best be carried out by multilateral rather than unilateral action.
In recognition of this, Ireland in common with its EC partners is a party to the Montreal Protocol on substances that deplete the ozone layer which came into force on 1 January 1989.
As regards chlorofluorocarbons, the controls require the stabilisation of consumption at 1986 levels from 1 July 1989, a reduction of 20 per cent from 1 July 1993 and a reduction of 50 per cent from 1 July 1998.
historical-debates.oireachtas.ie /D/0386/D.0386.198902070003.html   (905 words)

 Purification of chlorofluorocarbons - Patent 4849558   (Site not responding. Last check: 2007-10-07)
Chlorofluorocarbon solvents, particularly R113, may be purified by removing SO.sub.2 or its equivalent to the level of below about 0.3 ppb by contact with alumina or zeolites.
Trace contamination of chlorofluorocarbon solvents such as R113 containing less than about 10 ppb, typically about 3 ppb (as sulfur), of sulfur compounds may be reduced below the 0.3 ppb level by contacting the solvent with an adsorbent for sulfur compounds at ambient temperature, say about 20.degree.
Chlorofluorocarbons, particularly R113 (trichlorotrifluoroethane), are widely used for cleaning electronic parts.
www.freepatentsonline.com /4849558.html   (2097 words)

 CHLOROFLUOROCARBONS IN THE WESTERN MEDITERRANEAN SEA   (Site not responding. Last check: 2007-10-07)
As other chemical tracers such as nutrients, CFC's are used to characterise the different water masses and their main interest resides in their transient tracer behaviour which can give estimates in the ventilation time of newly formed waters.
The depth of the chlorofluorocarbons minimum was well under the salinity maximum characteristics of the Intermediate Waters.
An alternate origin may be the existence of different values in the vertical diffusion coefficient for salinity and chlorofluorocarbons.
www.imbc.gr /imbc/biblio_serv/mast/X0031_141.html   (499 words)

 Chlorofluorocarbons CFCs | Doing my Homework   (Site not responding. Last check: 2007-10-07)
Chlorofluorocarbons were preferred because they are non-toxic, non-flammable, and non-reactive with other chemical compounds.
With these safety features, and other stable thermodynamic properties, chlorofluorocarbons were ideal to be used as coolants for commercial and home refrigeration units, aerosol propellants, electronic cleaning solvents, and blowing agents.
As stated earlier, chlorofluorocarbons are attributed to the rapid depletion of the ozone layer.
www.doingmyhomework.com /show_essay/2777.html   (165 words)

 Chlorofluorocarbons - NSC   (Site not responding. Last check: 2007-10-07)
Of those releases, 689,884 pounds were air emissions; 13,005 pounds were surface water discharges; 250 pounds were released by underground injection; 0 pounds were released to land; and, 107 pounds were transferred off-site for disposal.
In 1998, 1,343,600 pounds of chlorofluorocarbons waste were managed; 80,050 pounds were recycled on-site; 252,664 pounds were recycled off-site; 0 pounds were used for energy recovery on-site; 90 pounds were used for energy recovery off-site; 238,680 pounds were treated on-site; 66,583 pounds were treated off-site; and 705,623 pounds were released on-and off-site.
The 10 states releasing the largest amounts of chlorofluorocarbons in 1998 were: Louisianna (148,865 pounds); New Jersey (115,141 pounds); Texas (97,240 pounds); Illinois (85,964 pounds); Kansas (39,050 pounds); Massachusetts (38,900 pounds); Puerto Rico (35,518 pounds); Kentucky (32,433 pounds); North Carolina (29,517 pounds); and Washington (25,030 pounds).
www.nsc.org /library/chemical/chlorofl.htm   (1017 words)

Specialty definitions using "CHLOROFLUOROCARBONS": CFCs ♦ fluorocarbons, Freon ♦ greenhouse gas, greenhouse gases ♦ Hydrochlorofluorocarbons ♦ Ozone depleting substance, Ozone Depletion ♦ radiatively active gases.
Quantitative restrictions exist for certain textiles and garments to Canada, EU countries and the U.S. Items such as rubber, timber, granite, satellite dishes and receivers, and chlorofluorocarbons are subject to export control and licensing.
"CHLOROFLUOROCARBONS" is used about 93 times out of a sample of 100 million words spoken or written in English.
www.websters-online-dictionary.org /definition/english/Ch/Chlorofluorocarbons.html   (623 words)

 EPA History - Statement at a Public Meeting on Chlorofluorocarbons   (Site not responding. Last check: 2007-10-07)
We will also examine by June 1978 the environmental risks, benefits and available alternatives to other chlorofluorocarbon uses such as refrigerants and foams which are used widely in padding and insulation.
On October 18, 1976, EPA notified the producers, formulators and registrants of pesticides that chlorofluorocarbons should be discontinued unless they can be shown to be essential to the safety and efficacy of the product.
The meeting is intended to produce information on alternative products and propellants for chlorofluorocarbon aerosols, the economic impact of phasing out nonessential chlorofluorocarbon aerosols, and the health and environmental effects.
www.epa.gov /history1/topics/ozone/04.htm   (763 words)

 Nat' Academies Press, Toxicity of Alternatives to Chlorofluorocarbons: HFC-134a and HCFC-123 (1996)
Toxicity of Alternatives to Chlorofluorocarbons: HFC-134a and HCFC-123 2 Evaluation of the Dog Cardiac Sensitization Test INTRODUCTION This chapter contains an evaluation of the suitability of the method used for detecting and quantifying the risk of cardiac sensitization from exposure to CFCs, their substitutes, and other hydrocarbons.
Toxicity of Alternatives to Chlorofluorocarbons: HFC-134a and HCFC-123 Deaths presumed to be due to cardiac arrest, as a result of the sensitization of the heart to epinephrine, have also been attributed to the intentional “sniffing” of aerosol propellants and from overexposure to VOCs in industrial settings.
Toxicity of Alternatives to Chlorofluorocarbons: HFC-134a and HCFC-123 dition, isolated ectopic beats are not uncommon, are not lifethreatening, and are therefore not indicative of cardiac sensitization.
books.nap.edu /books/NI000049/html/13.html   (2986 words)

 Find Free Essays on Chloroflourocarbon
CHLOROFLUOROCARBON Chlorofluorocarbons are any group of synthetic organic compounds containing chlorine, fluorine, and carbon.
Chlorofluorocarbons are non-poisonous, and non-flammable chemicals that cause air pollution.
Chlorofluorocarbons such as Dichlorodifluoromethane known as CFC-12 and Trichlorofluoromethane known as CFC-11 are useful propellants in aerosol spray products.
www.findfreeessays.com /show_essay/438.html   (147 words)

chlorofluorocarbons (CFCs), organic compounds that contain carbon, chlorine, and fluorine atoms.
CFCs are highly effective refrigerants that were developed in response to the pressing need to eliminate toxic and flammable substances, such as sulfur dioxide and ammonia, in refrigeration units and air conditioners.
Lung deposition of hydrofluoroalkane-134a beclomethasone is greater than that of chlorofluorocarbon fluticasone and chlorofluorocarbon beclomethasone *: a cross-over study in healthy volunteers.
www.infoplease.com /ce6/sci/A0812001.html   (672 words)

 Ozone/CFCs/Chlorofluorocarbons   (Site not responding. Last check: 2007-10-07)
I've always wondered how those nasty chlorofluorocarbon molecules that escape from my car air conditioner manage to avoid the amorous embraces of surface and low-level ozone molecules and head south.
Eventually, I gather, they mange to reach the polar regions, rise to the rarefied altitudes of the ozone layer, and find their true soul mates.
The largest sources of chlorine atoms in the stratosphere are chlorofluorocarbons (CFCs), chemical compounds of carbon, chlorine, and fluorine, in particular, CFC-11, (CCI3F) and CFC-12 (CCI2F2).
www.weatherwise.org /qr/qry.ozone.html   (570 words)

 The Journal of Coatings Technology: Du Pont company accelerates phaseout of chlorofluorocarbons and halons. (Government ...   (Site not responding. Last check: 2007-10-07)
The Journal of Coatings Technology: Du Pont company accelerates phaseout of chlorofluorocarbons and halons.
Du Pont company accelerates phaseout of chlorofluorocarbons and halons.
Du Pont Company, Wilmington DE, has announced that it is accelerating its phaseout of chlorofluorocarbons (CFCs) and Halons by three to five years in response to scientific data released by the United Nations Environment Programme (UNEP) and the World Meteorological Organization.
www.highbeam.com /library/doc0.asp?DOCID=1G1:11863398&refid=ip_encyclopedia_hf   (196 words)

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