Freons banning

I iL-un 12 (CCljFj) which is now banned by the ozone protection treaty. Also used is Dichloro-difluoromethane, Freon 22 (CHClFj), and chloro-difluoromethane. Several analogous compounds containing carbon, fluorine, chlorine, and sometimes hydrogen are available. 

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. 

CFCs CC12F2, CCI3F, CCIF3 chlorofluorocarbons (freons, Freon-12) colourless, odourless gas CFCs are now banned by the Montreal Protocol in the past, were used as refrigerants and aerosols... 

Because they pose environmental problems, Freons were banned years ago by the U.S. government for use in aerosol cans, atid they have recently been banned for use in air conditioners and refrigerators. 

A carbon atom can be bonded to as many as four halogen atoms, so an enormous number of organic halides can exist. Completely fluorinated compounds are known as fluorocarbons or sometimes perfluorocarbons. The fluorocarbons are even less reactive than hydrocarbons. Saturated compounds in which all H atoms have been replaced by some combination of Cl and F atoms are called chlorofluorocarbons or sometimes freons. These compounds were widely used as refrigerants and as propellants in aerosol cans. However, the release of chlorofluorocarbons into the atmosphere has been shown to be quite damaging to the earth s ozone layer. Since January 1978, the use of chlorofluorocarbons in aerosol cans in the United States has been banned, and efforts to develop both controls for existing chlorofluorocarbons and suitable replacements continue. The production and sale of freons have been banned in many countries. 

Freon a clear liquid with a sweet smell that is manufactured and does not occur naturally. Freon is most often found as a colorless gas. It s not flammable and doesn t dissolve in water very easily. It was once used in the production of refrigeration fluid and propellants for aerosol cans, as a pesticide, as a cleaning fluid and degreasing agent, in fire extinguishers, and in spot removers. These uses have been banned since the early 1990 s and it is now only used in some industrial applications. 

Although manufacture of CFCs was banned on December 31, 1995, the C—F and C—Cl bonds of CFCs are so strong that the molecules may remain in the atmosphere for 120 years. Within 5 years they diffuse into the upper stratosphere where ultraviolet photons can break the C—Cl bonds. This process releases chlorine atoms, as shovm here for Freon-12 ... 

Since the ban on CFC production has been adopted, manufacturers are replacing Freon products with two related groups of compounds, the hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). These hydrogen-containing compounds are less energy efficient than the CFCs, but they are considered safer (although not entirely safe) for the environment. 

Stratospheric Ozone Protection Program, Clean Air Act sections 601-618 40 CFR Prut 82. Contains a list of ozone-depleting substances. Bans certain freons, requires freon recycling. 

Method 413 has recently become controversial in the fact that the manufacture of the common extraction solvent used in the method, 1,1,2-trichlorotrifluoroethane (TCTFE), itself a fluorocarbon (Freon 113), is banned. The attributes of TCTFE are such that it enabled this method to move from a purely gravimetric approach, EPA Method 413.1 (Gravimetric, Separatory Funnel Extraction), to an instrumental approach whereby the carbon-to-hydrogen stretching frequency in the infrared spec-... 

In 1975 a study by the National Academy of Sciences supported the predictions of Rowland and Molina, and since January 1978 the use of freons in aerosol cans in the United States has been banned. 

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. 

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