Refrigerators, Freon

Many substances react in the gas phase rather than in solution. An important example is the process thought to deplete the ozone layer the reaction between gaseous ozone, O3, and chlorine radicals, high up in the stratosphere. Ultimately, the chlorine derives from volatile halocarbon compounds, such as die refrigerant Freon-12 or the methyl chloroform thinner in correction fluid. 

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. 

Owing to the extreme chemical activity of fluorine, the chief uses of this element arise in connection with the production of its compounds. Thus, sodium fluoride is commonly used as a flux, as an insecticide, and as a wood preservative. Ammonium fluoride is sometimes used as a disinfectant. The compound dichlorodifluoromethane (CC12F2) is used as an insecticide propellent and is an important commercial refrigerant (Freon), particularly well suited for use in domestic refrigeration units. 

The main uses of halogenatcd methanes are as refrigerants (Freons), propellants. dry cleaning solvents, in Teflon manufacture, narcotics, and fire extinguishing systems. 

Refrigeration uses non-aqueous refrigerant (Freon) Active... 

Halothane (No. 11) was introduced in 1956 and was soon among the most-used anesthetics it became a prototype. It is quite volatile (b. 50°) and nonflammable, which are both desirable attributes. It has a good safety record over several decades. This is somewhat surprising considering halothane s similarity of physical and anesthetic properties to chloroform. Even though no SARs can really be carried out, halothane s low toxicity must be attributed to the fluorine atoms. In addition, the various fluorinated refrigerants (Freons) developed earlier were also found to be nontoxic.5... 

A variety of halogen-containing compounds find uses as refrigerants (Freon), dry-cleaning fluids, and anesthetics, and as solvents in which to carry out organic reactions. 

Refrigerant Freon 12 0 Refrigerant Propane 0 Refrigerant Propylene 0 Steam 100PSI 0 Steam 165PSI 0 Steam 400PSI... 

Existing stockpiles of the refrigerant Freon-12, CF2CI2, must be destroyed under the auspices of the Montreal Protocol because of their potential for harming the ozone layer. One method for doing this involves reaction with sodium oxalate ... 

An automobile air conditioner has a condenser that removes 60,000 BTU/hr from a refrigerant (auto speed 40 mph ambient temperature of 95°F). Refrigerant temperature is 150°F. U for the finned tube exchanger is 35 BTU/hr ft with an air temperature rise of 10°F. If the U varies as a 0.7 power of velocity and air mass flow directly as velocity, find the percent performance redirection of the condenser a function of velocity (40 mph to 10 mph). Refrigerant (Freon 12) temperature is constant at 150°F. 

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