Freon CFC

C05-0071. Freons (CFCs) are compounds that contain carbon, chlorine, and fluorine in various proportions. They are used as foaming agents, propellants, and refrigeration fluids. Freons are controversial because of the damage they do to the ozone layer in the stratosphere. A 2.55-g sample of a particular Freon in a 1.50-L bulb at 25.0 °C has a pressure of 262 torr. What is the molar mass and formula of the compound ... 

Lovley DR, JC Woodward (1992) Consumption of freons CFC-11 and CFC-12 by anaerobic sediments and soils. Environ Sci Technol 26 925-929. 

The environmental hazard posed by this series of reactions is that the level of ultraviolet radiation reaching the earth would be expected to increase as more and more ozone molecules are destroyed. Ultraviolet radiation has been implicated in a number of biological problems for plants, animals, and humans, including an increase in skin cancer and in eye problems. In response to this threat, most of the world s nations have agreed to reduce the amount of Freons, CFCs, and other ozone-depleting chemicals produced and sold each year. 

Loosli HH, Lehmaim BE, Thalmann C, Andrews JN, Florkowski T (1992) Argon-37 and argon-39 Measured concentrations in ground water compared with calculated concentrations in rock. In Isotope techniques in water resources development (IAEA-SM-319). IAEA, Vienna, p 189-201 Lovley DR, Woodward JC (1992) Consumption of freons CFC-11 and CFC-12 by anaerobic sediments and soils. Environ Sci Technol 26 925-929... 

All of these three capabilities were provided by single solvents whose manufacture is now banned (TCA, Freon (CFC-113), HCFC-141b), or are provided by single solvents whose use raises significant concern about SHE issues (TCE, PCE, n-PB). 

In many shops into and through the early 1990s, solvent cleaning was done using 1,1,1-trichloro-ethane (TCA) or "Freon" (CFC-113), with little control of emissions. It was then discovered that emitted solvents catalyzed deterioration of the stratospheric ozone layer above Earth, and their manufaaure was banned per the Montreal Protocol. 

Freons The trade name for the series of chlorofluorocarbons (CFCs),... 

The formed mixture is composed of trichlorofluoromethane (Freon-11) and dichlorodifluoromethane (Freon-12). These compounds are used as aerosols and as refrigerants. Due to the depleting effect of chlorofluorocarbons (CFCs) on the ozone layer, the production of these compounds may be reduced appreciably. 

Much research is being conducted to find alternatives to CFCs with little or no effect on the ozone layer. Among these are HCFC-123 (HCCI2CF3) to replace Freon-11 and HCFC-22 (CHCIF2) to replace Freon-12 in such uses as air conditioning, refrigeration, aerosol, and foam. These compounds have a much lower ozone depletion value compared to Freon-11, which was assigned a value of 1. Ozone depletion values for HCFC-123 and HCFC-22 relative to Freon-11 equals 0.02 and 0.055, respectively. ... 

The chlorine atoms that catalyze the decomposition of ozone come from chlorofluorocarbons (CFCs) used in many refrigerators and air conditioners. A major culprit is CF2CI2, Freon, which forms Cl atoms when exposed to ultraviolet radiation at 200 nm ... 

In 1987 an international treaty was signed in Montreal to cut back on the use of CFCs. Production of Freon in the United States ended in 1996. It has been replaced in automobile air conditioners by a related compound with no chlorine atoms, C2H2F4 ... 

The chlorine atoms in the upper atmosphere come from the breakdown of CF2 CI2 and other similar chlorofluorocarbons (CFCs), known commercially as Freons. Production of these compounds was more than one million tons in 1988, largely for use in relrigerators and air conditioners. Once released into the atmosphere, CFCs diffuse slowly upward in the atmosphere until they reach the ozone layer. There, ultraviolet light Irom the sun splits off chlorine atoms. These react with ozone, with dramatic results. Annual ozone decreases have exceeded 50% above Antarctica. The background photo shows the Antarctic hole (red-violet) on September 24, 2003. 

Soon, as Midgley put it, Everything looked right. Within a few hours, they had identified a whole new class of potential compounds the chloro-fluorocarbons, later nicknamed CFC s, and trademarked Freon by Du Pont. 

Industrial and Engineering Chemistry. 29 (Feb. 1937) 241-244. Kettering file 19-103. Source for high school science periodic table used in search for antiknock how CFCs discovered and how Freon discovered. 

Production of freons or chlorofluorocarbons (CFCs) (chlorofluoromethane and chlorofluoroethanes) began in 1930 and the world production reached 2 billion pounds annually by 1974. 

Synonyms HCFC-141b 1,1 -dichloro-1 -fluoroethane Freon 141 CFC 141, 141b Refrigerant 141b CHEMID 1998... 

This method (EPA 1664) is a liquid-liquid extraction gravimetric procedure that employs n-hexane as the extraction solvent, in place of 1,1,2-trichloroethane (CFC-113) and/or 1,2,2-trifluoroethane (Freon-113), for determination of the conventional pollutant oil and grease. Because the nature and amount of material determined are defined by the solvent and by the details of the method used for extraction, oil and grease method-defined analytes are used. The method may be modified to reduce interferences and take advantage of advances in instrumentation provided that all method equivalency and performance criteria are met. However, n-hexane is a poor solvent for high-molecular-weight petroleum constituents (Speight, 1999, 2001). Thus, the method will produce erroneous data for samples contaminated with heavy oils. 

At issue is a group of man-made chemicals called chlorofluorocarbons (CFCs), which are used as the refrigeration fluids (Freon) in the air-conditioning and refrigeration units of automobiles, homes, and industry and which, in the past, were used as the pressure gas in spray cans of paint, deodorants, and so forth. There are a number of compounds containing... 

Chlorofluorocarbons (CFCs) come in many forms, including those used as propellants for spray cans and for refrigeration (freon). They were banned as being potentially harmful to the ozone layer of the atmosphere. In 1987 an international agreement was signed by about 90 nations to reduce the use of CFCs by 50% by the year 2000. This did not seem adequate, so in 1990 a new treaty called for the elimination of the use of all CFCs by industrial nations. Some third world countries (e.g., China, India, Russia, and Mexico) still make and sell CFCs, some of which are smuggled into the United States. 

Freon is a commercial trademark for a series of fluorocarbon products used in refrigeration and air-conditioning equipment, as aerosol propellants, blowing agents, fire extinguishing agents, and cleaning fluids and solvents. Many types contain chlorine as well as fluorine, and should be called chlorofluorocarbons (CFCs) [85,86]. 

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