Propellants chlorinated-fluorocarbons

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. ... 

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. 

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

Composed of carbon, hydrogen, fluorine, and chlorine, chlorinated fluorocarbons (CFCs) are all l halides used in aerosol propellents and refrigerants. CFCs have been replaced by other compounds because they generate chlorine atoms in the upper atmosphere, which deplete the ozone layer (see Section 12.15). Many aerosols are now propelled by carbon dioxide. Different refrigerant molecules (called hydrofluorocarbons, HFCs) are being used in refrigerators and air conditioners. 

Used industrially in the manufacture of fluorocarbons as a chemical intermediate in the manufacture of sulfur hexafluoride, chlorine trifluoride, bromine trifluoride uranium hexafluoride, molybdenum hexafluoride, perchloryl fluoride, and oxygen difluoride and as a rocket propellant. 

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]. 

Chlorine trifluoride is used in rocket propellant incendiaries and in processing of nuclear reactor fuel. It also is used as a fluorinating agent and as an inhibitor of fluorocarbon polymer pyrolysis. 

Fluorocarbons (FCs) Organic compounds analogous to hydrocarbons in which one or more hydrogen atoms are replaced by fluorine. FCs were once used in the United States as a propellant for domestic aerosols and are now found mainly in coolants and some industrial processes. FCs containing chlorine are called chlorofluorocarbons (CFCs). These are believed to be modifying the ozone layer in the stratosphere and are responsible for allowing more harmful solar radiation to reach the Earth s surface. 

Aerothene [Dow]. TM for a group of chlorinated solvents used as vapor pressure depressants, or with compressed gases to replace fluorocarbon propellant systems. 

In 1974, Sherwood Rowland and Mario Molina published their conclusion of an extremely careful study of atmospheric chemistry chloro-fluorocarbons, chemicals used in a number of applications (e.g., as refrigeration fluids and propellants in spray cans), when bombarded by solar UV-rays in the upper atmosphere, released chlorine atoms, which in... 

The chemical names of these products conform to practice in the United States. Halogens are listed in alphabetical order as bromo, chloro, fluoro, and iodo. For mixtures, the higher pressure material is listed first. An exception to this rule is found in some aerosol propellant mixtures where products not containing fluorine (hydrocarbons, chlorinated compounds, etc.) are listed last. Higher boiling fluorocarbons are usually placed with other fluorocarbons in order of decreasing pressure. 

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