Chlorofluorocarbons manufacturers

Cj Derivatives. The clilorinated methanes, chloroform, methylene chloride, and carbon tetrachloride, consumed approximately 0.8 million tons of clilorine in 1987 and aggregate growth rates from this segment of the industry are expected to remain relatively flat through 1992. Because of its contribution to ozone depletion, carbon tetrachloride use in chlorofluorocarbon manufacture will be phased out in compliance with the recent Montreal Accord. In addition, environmental pressures are expected to continue to impact the use of methylene chloride in aerosol and paint remover applications. Some of the decreases in C1 derivatives should be offset by positive growth for chloroform in HCFC-22 manufacture, which has not been implicated in ozone depletion (see CHLOROCARBONS AND CHLOROHYDROCARBONS, METHYL CHLORIDE METHYLENE CHLORIDE CHLOROFORM CARBON TETRACHLORIDE). 

In the U.S.A., environmental pressures are causing a continuing fall in demand for the two major products, perchloroethylene (120 kt per annum), used for dry cleaning and chlorofluorocarbon manufacture, and 1,1,1-trichloroethane (200 kt per annum), for cold cleaning and vapour degreasing of metals. European production of 1,1,1-trichloroethane is believed to be on a similar scale. 

Production of hydrogen fluoride from reaction of Cap2 with sulfuric acid is the largest user of fluorspar and accounts for approximately 60—65% of total U.S. consumption. The principal uses of hydrogen fluoride are ia the manufacture of aluminum fluoride and synthetic cryoHte for the Hall aluminum process and fluoropolymers and chlorofluorocarbons that are used as refrigerants, solvents, aerosols (qv), and ia plastics. Because of the concern that chlorofluorocarbons cause upper atmosphere ozone depletion, these compounds are being replaced by hydrochlorofluorocarbons and hydrofluorocarbons. 

It appears that the ultimate replacements for the high volume chlorofluorocarbon products are to be more highly fluorinated organic chemicals, thus requiring significantly higher volumes of HF in thek manufacture. 

Ninety-six percent of the EDC produced in the United States is converted to vinyl chloride for the production of poly(vinyl chloride) (PVC) (1) (see Vinyl polymers). Chloroform and carbon tetrachloride are used as chemical intermediates in the manufacture of chlorofluorocarbons (CECs). Methjiene chloride, 1,1,1-trichloroethane, trichloroethylene, and tetrachloroethylene have wide and varied use as solvents. Methyl chloride is used almost exclusively for the manufacture of silicone. Vinylidene chloride is chiefly used to produce poly (vinylidene chloride) copolymers used in household food wraps (see Vinylidene chloride and poly(vinylidene chloride). Chloroben2enes are important chemical intermediates with end use appHcations including disinfectants, thermoplastics, and room deodorants. 

Recently several patents have been issued (16—18) describing the use of 1,2-dichloroethylene for use in blends of chlorofluorocarbons for solvent vapor cleaning. This art is primarily driven by the need to replace part of the chlorofluorocarbons because of the restriction on their production under the Montreal Protocol of 1987. Test data from the manufacturer show that the cleaning abiUty of these blends exceeds that of the pure chlorofluorocarbons or their azeotropic blends (19). 

World capacity and demand for tetrachloroethylene were approximately 1100 and 845 thousand metric tons ia 1974, respectively. Although demand iacreased iato the mid-1980s, siace then demand for tetrachloroethylene has decreased significantly as a result of the phaseout of chlorofluorocarbons, the use of more efficient dry-cleaning equipment, and iacreased reclamation of waste solvent. World capacity and demand as of 1988 are provided ia Table 2 Several United States manufacturers have shut down faciUties ia the last fifteen years. Current manufacturers and their capacities are Hsted ia Table 3. United States production and sales history is shown ia Table 4. 

A leader in the refrigerants industry, we manufacture and supply customers with economical chlorofluorocarbon (CFC) replacements and non-ozone depleting hydrofluorocarbon (HFC) refrigerants for automotive, home, commercial and transportation uses. In the Americas and Asia, you can find these products under the Genetron name and in Europe and the Middle East under Honeywell Refrigerants. 

The other global environmental problem, stratospheric ozone depletion, was less controversial and more imminent. The U.S. Senate Committee Report supporting the Clean Air Act Amendments of 1990 states, Destruction of the ozone layer is caused primarily by the release into the atmosphere of chlorofluorocarbons (CFCs) and similar manufactured substances—persistent chemicals that rise into the stratosphere where they catalyze the destruction of stratospheric ozone. A decrease in stratospheric ozone will allow more ultraviolet (UV) radiation to reach Earth, resulting in increased rates of disease in humans, including increased incidence of skin cancer, cataracts, and, potentially, suppression of the immune system. Increased UV radiation has also been shown to damage crops and marine resources."... 

The products are available as tablets, capsules, liquids (in the form of solutions, suspensions, emulsions, gels, or injectables), creams (usually oil-in-water emulsions), ointments (usually water-in-oil emulsions), and aerosols, which contain inhalable products or products suitable for external use. Propellants used in aerosols include chlorofluorocarbons (CFCs), which are being phased out. Recently, butane has been used as a propellant in externally applied products. The major manufactured groups include ... 

During the 1980s, it became recognized that chlorofluorocarbons (CFCs), widely used as aerosol propellants, are damaging the ozone layer, and aerosol manufacturers were asked to use other propellants. Some... 

Although many syntheses of chlorofluorocarbons and hydrochlorofluorocarbons have been published, those actually used in manufacturing processes are limited. By far the most important is the original Swarts reaction [5]. 

In this penod of mtense development cloaked in industrial secrecy, not all manufacturers have declared the routes they chose for their mitial production plants Preferred long-term processes are even less clear In some cases, the technologies that sufficed for the production of chlorofluorocarbons and hydrochlorofluorocar-bons would be pushed to theu limits as processes for the replacements For example... 

The primar> uses for hydrogen fluoride in the United States arc in the manufacture of chlorofluorocarbons, aluminum fluoride, sodium aluminum fluoride (ciyolitc). md uranium tetrafluoride, and in petroleum alkylation. 

All Group 14/IV elements form liquid molecular tetrachlorides. The least stable is PbCl4, which decomposes to solid PbCl2 when it is warmed to about 50°C. Carbon tetrachloride, CC14 (tetrachloromethane), was widely used as an industrial solvent however, now that it is known to be carcinogenic, it is used primarily as the starting point for the manufacture of chlorofluorocarbons. Carbon tetrachloride is formed by the action of chlorine on methane ... 

Some physicians recommend epinephrine metered-dose inhalers as an alternative to epinephrine autoinjectors. While a few inhalations might relieve mild or moderate respiratory symptoms, for relief of life-threatening airway obstruction or shock, adults need to inhale 20-30 puffs and children need to inhale 10-20 puffs, which is hard to do [35]. Epinephrine metered-dose inhalers contain chlorofluorocarbon propellants. For environmental reasons, they might not be manufactured in the future. 

Mathematical models are also used for estimating releases, but these are usually relatively simple. For example, if it is known that X kg of a chlorofluorocarbon is manufactured annually, and Y percent enters spray cans, and Z percent of a spray can is usually left unexhausted, then XY(100-Z)/10 kg of that CFC are released to the atmosphere per year. The average discharge rate (kg/sec) nationwide then can be computed easily. (For simplicity in this example, we ignore the contributions from leaking discarded cans and changes in production and use levels.)... 

Amorphous fluoropolymers have many applications in the areas of advanced materials where they are used in applications requiring thermal and chemical resistance. Their manufacture is hindered by their low solubility in many solvents. Many fluoropolymerizations cannot be carried out in hydrocarbon solvents because the radical abstraction of hydrogen atoms leads to detrimental side reactions. Chlorofluorocarbons (CFCs) were thus commonly used, but their use is now strictly controlled due to their ozone depleting and greenhouse gas properties. Supercritical carbon dioxide is a very attractive alternative to CFCs and it has been shown that amorphous fluoropolymers can be synthesized by... 

The chlorofluorocarbon compounds of methane and ethane are collectively known as freons. They are extremely stable, unreactlve, non-toxic, non-corrosive and easily liquefiable gases. Freon 12 (CCI2F2) Is one of the most common freons In Industrial use. It Is manufactured from tetrachloromethane by Swarts reaction. These are usually produced for aerosol propellants, refrigeration and air conditioning purposes. By 1974, total freon production In the world was about 2 billion pounds annually. Most freon, even that used In refrigeration, eventually makes Its way Into the atmosphere where It diffuses unchanged Into the stratosphere. In stratosphere, freon Is able to Initiate radical chain reactions that can upset the natural ozone balance (Unit 14, Class XI). 

Hexachlorobutadiene is used as a chemical intermediate in the manufacture of rubber compounds (ERA 1982d). Lesser quantities of hexachlorobutadiene are used as a solvent, a fluid for gyroscopes, a heat transfer liquid, hydraulic fluid, and as a chemical intermediate in the production of chlorofluorocarbons and lubricants (ERA 1980 lARC 1979 Verschueren 1983). Small quantities are also used as a laboratory reagent (ERA 1982d). In the international market, Russia is reported to be one of the major users of hexachlorobutadiene, where it is used as a fumigant on grape crops. 

The magnitude of the effect of this scheduled phaseout on total carbon tetrachloride production is uncertain, since the Halogenated Solvents Industry Alliance estimates that only about 3% of the chemical manufactured in the U.S. is used in nonfeedstock applications (EPA 1991). Nevertheless, since the major current use of carbon tetrachloride is in the production of chlorofluorocarbons (see Section 4.3), and production of these chemicals has dropped significantly in recent years (C EN 1993) and is also scheduled for phase-out by 1996, a significant reduction in carbon tetrachloride production is expected during this decade. 

Carbon tetrachloride is a stable chemical that is degraded very slowly, so there has been a gradual accumulation of carbon tetrachloride in the environment as a consequence of releases from human activities. Until 1986, the largest source of release was from the use of carbon tetrachloride as a grain fumigant, but this practice has now been stopped. Other releases of carbon tetrachloride may occur during carbon tetrachloride production or during the use of carbon tetrachloride in the manufacture of chlorofluorocarbons and other chemical products. 

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