Chlorinated fluorocarbon

Chlorofluorocarbons (CFCs). Prior to 1978 most aerosol products contained chlorofluorocarbon propeUants. Since that time, the use of chlorinated fluorocarbons for aerosols has been seriously curtailed. These compounds have been impHcated in the depeletion of the ozone (qv) layer and are considered to be greenhouse gases (see Airpollution Atmospheric modeling). 

TSCA also addresses the problem of polychlorinated biphenyls (PCBs) and chlorinated fluorocarbons (CECs). EPA has developed regulations on the cleanup, handling, and disposal of PCBs. The manufacture and use of CECs has been banned for all but essential uses, in accordance with the Montreal Agreement, an international treaty on worldwide use of CECs. 

Plastics. Citric acid and bicarbonate are used as an effervescent blowing agent to foam polystyrene for insulated food and beverage containers replacing blowing agents such as chlorinated fluorocarbons (194—206). 

Chlorinated fluorocarbons (CFCs), 21 591 Chlorinated glycolurils, 73 109-110 Chlorinated hydantoins, 13 110 Chlorinated hydrocarbons (CHC) contamination by, 23 111—112 for PVC polymers, 25 674 Chlorinated isocyanurates end use of chlorine, 6 135t as pool sanitizers, 26 175-176 Chlorinated methanes... 

Formulated Commercial Products and Byproducts insecticides, pesticides. fungicides, herbicides, solvents, coatings, chlorinated fluorocarbons, petroleum and petrochemical products, plastics, fibers. 

The chloride is used to manufacture silicones, tetramethyl lead and triptane (2,2,3 trimethylbutane). Lesser uses include the manufacture of butyl rubber, higher halogenated methanes, methyl cellulose, quaternary ammonium compounds, methyl mercaptan, methionine, fungicides and pesticides (primarily the Me-arsenate herbicides). Recently the chlorinated fluorocarbons have replaced CH3CI as high volume refrigerants and propellants (ref. 32) Tables 12 and 13 list the chemical and physical properties and potential numbers of workers exposed to the monohalomethanes. 

Fluorocarbon greases (Krytox) originally required a chlorinated fluorocarbon for removal. In the last few years, it was found that an industrial solvent (such as BH-38 from Spartan Chemical Co. ) can remove Krytox. Tests that this author has conducted seem to show a film of some kind remains on the joint, so it is unknown exactly how safe it is to heat a joint or stopcock that has been cleaned with this technique. Do not use heat to remove Krytox because heating (> 260°C) will produce fumes (lethal fluorine compounds, such as HF) that are highly toxic. For more information on cleaning these greases, see Sec. 3.3.3. 

The modern pressurized metered dose inhaler (pMDI) was developed between 1955 and 1956. However, the pMDI had its roots in research carried out many years before.During the 1930s and 1940s, the discovery of liquefied propellants (chlorinated-fluorocarbons or freon propellants) such as CFC12, CFC114, CFCll, and CFC22 was a major step in the realization of a portable inhaler. However, the first pMDI was not invented until 1956, when the metering valve used in the device was developed and patented. ... 

How is the book arranged In the first few chapters we examine the properties of dmgs and excipients in the solid state and in solution. Gases also are treated because of their importance in the design and use of therapeutic pressurised aerosols, which until recently have been derived from chlorinated fluorocarbons (CFCs), but now are based on volatile fluorinated hydrocarbons (HFAs). 

The Clean Air Act of 1990 included a list of 189 toxic chemicals to be controlled and such emissions are to be reduced 90% by the year 2000. It also included the phasing out of chlorinated fluorocarbons (CFC s) and carbon tetrachloroflurocarbons (HCFC s) by 2030. 

Note the discussion in Chapter 2 about the phasing out of the availability of previously popular chlorinated fluorocarbons due to the negative effect these materials have on tiie earth s ozone layer. In the context of this recommendation, the alternatives described there should be used. 

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