Tetrachloroethylene manufacture

Chloroacetyl chloride is manufactured by reaction of chloroacetic acid with chlorinating agents such as phosphoms oxychloride, phosphoms trichloride, sulfuryl chloride, or phosgene (42—44). Various catalysts have been used to promote the reaction. Chloroacetyl chloride is also produced by chlorination of acetyl chloride (45—47), the oxidation of 1,1-dichloroethene (48,49), and the addition of chlorine to ketene (50,51). Dichloroacetyl and trichloroacetyl chloride are produced by oxidation of trichloroethylene or tetrachloroethylene, respectively. 

Vinyl chloride has gained worldwide importance because of its industrial use as the precursor to PVC. It is also used in a wide variety of copolymers. The inherent flame-retardant properties, wide range of plastici2ed compounds, and low cost of polymers from vinyl chloride have made it a major industrial chemical. About 95% of current vinyl chloride production worldwide ends up in polymer or copolymer appHcations (83). Vinyl chloride also serves as a starting material for the synthesis of a variety of industrial compounds, as suggested by the number of reactions in which it can participate, although none of these appHcations will likely ever come anywhere near PVC in terms of volume. The primary nonpolymeric uses of vinyl chloride are in the manufacture of vinyHdene chloride and tri- and tetrachloroethylene [127-18-4] (83). 

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. 

Inhibited grades of 1,1,1-trichloroethane are used in hundreds of different industrial cleaning appHcations. 1,1,1-Trichloroethane is preferred over trichloroethylene or tetrachloroethylene because of its lower toxicity. Additional advantages of 1,1,1-trichloroethane include optimum solvency, good evaporation rate, and no fire or flash point as determined by standard test methods. Common uses include cleaning of electrical equipment, motors, electronic components and instmments, missile hardware, paint masks, photographic film, printed ckcuit boards, and various metal and certain plastic components during manufacture (see Metal surface treatments). 

The only significant use of 1,1,2,2-tetrachloroethane is as a feedstock in the manufacture of trichloroethylene, tetrachloroethylene, and 1,2-dichloroethylene. Although it is an excellent solvent, its use should be discouraged in view of its high toxicity. 

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. 

Hexachlorobutadiene does not occur naturally in the environment. It is formed during the processing of other chemicals such as tetrachloroethylene, trichloroethylene, and carbon tetrachloride. Hexachlorobutadiene is an intermediate in the manufacture of rubber compounds and lubricants. It is used as a fluid for gyroscopes, a heat transfer liquid, or a hydraulic fluid. Outside of the United States it is used to kill soil pests. 

Hexachlorobutadiene was first prepared in 1877 by the chlorination of hexyl oxide (lARC 1979). Commercial quantities of hexachlorobutadiene have never been produced in the United States. The primary source of hexachlorobutadiene found in the United States is inadvertent production as a waste by-product of the manufacture of certain chlorinated hydrocarbons, such as tetrachloroethylene, trichloroethylene, and carbon tetrachloride (ERA 1980 Yang 1988). In 1982, ERA reported an annual volume of about 28 million pounds of hexachlorobutadiene inadvertently produced as a waste by- product from this source (ERA 1982b HSDB 1993). Table 4-1 summarizes information on U.S. companies that reported the production, import, or use of hexachlorobutadiene in 1990 based on the Toxics Release Inventory TRI90 (1992). The TRI data should be used with caution since only certain types of facilities are required to report. This is not an exhaustive list. 

Carbon tetrachloride is produced by exhaustive chlorination of a variety of low molecular weight hydrocarbons such as carbon disulfide, methanol, methane, propane, and ethylene dichloride (CEH 1985 lARC 1979). It is also produced by thermal chlorination in the production of tetrachloroethylene. Since the U.S. Food and Drug Administration banned the sale of carbon tetrachloride in any product used in the home, its production initially declined at approximately 8% a year from 1974 to 1981 (HSDB 1992). From 1981 to 1988 the United States consistently produced between 573-761 million pounds (260,000-350,000 metric tons) of carbon tetrachloride per year (C EN 1992 SRI 1988 USITC 1986). Carbon tetrachloride production dropped to 413 million pounds (187,000 metric tons) per year in 1990, and to 315 million pounds (143,000 metric tons) in 1991 (C EN 1992, 1993 USITC 1986, 1991). Carbon tetrachloride is currently manufactured at five facilities in the United States Akzo Chemical, Inc., New York, New York Dow Chemical Company, Midland, Michigan Vulcan Materials Company, Birmingham, Alabama Occidental Chemical Corporation, Dallas, Texas and LCP Chemicals, West Virginia Inc., Moundsville, West Virginia (USITC 1991 HSDB 1992). 

Manufacturing processes in which organic products are made are of special interest to green chemists for a variety of reasons, largely because so many of the raw materials used to make such products, the by-products formed in the reactions, and the final products themselves are likely to he toxic or hazardous in other ways. Historically, the problem with such manufacturing processes is that they have required the use of organic solvents, such as carbon tetrachloride, chloroform, tetrachloroethylene, trichloroethylene, 1,1,1-trichloro-ethane, benzene, toluene, and xylene. A major thrust, then, has been to find satisfactory substitutes for these organic solvents. 

Tetrachloroethanc is an intermediate in one proeess for the manufacture of trichloroethylene and tetrachloroethylene and has been reported to occur as an impurity in these widely used products. It has been detected at low levels in ambient air and in drinking-water. 

Solvent manufacturing is an important part of the economy. Annual productions of carbon disulfide and xylene range in the millions of tons (Arlien-Soborg 1992 Snyder and Andrews 1996). The annual production of 1,1,1-trichloroethane, found in 250 household chemicals, exceeds 700 million tons (Kurt and Buffler 1995). With this level of production, a significant number of workers are at risk for exposure. More than 450,000 workers have exposure risks to per-chloroethylene or tetrachloroethylene in the dry cleaning industry (White et al. 1990). Various sources indicate possible exposures of 3.5 million workers to trichloroethylene and 140,000 potentially... 

ORIGIN/INDUSTRY SOURCES/USES under anaerobic conditions, it is formed by the breakdown of trichloroethylene, tetrachloroethylene, and 1,1,2,2-tetrachloroethane solvent for waxes, resins, and acetylcellulose a refrigerant in extraction of rubber manufacture of pharmaceuticals artificial pearls in the extraction of oils and fats from fish and meat... 

OTHER COMMENTS used in cleaning and degreasing of metals used in the manufacture of paint removers, lacquers, varnishes, and varnish removers used as a solvent in preparation of adhesives useful as a chemical intermediate in manufacture of trichloroethylene and tetrachloroethylene use in refining of waxes and resins note use has been forbidden or restricted in certain countries. 

Releases to the Environment from Facilities That Manufacture or Process Tetrachloroethylene... 

These data show there has been an overall decline of about 50% between 1983 and 1993. The future production market for tetrachloroethylene has been projected at either zero growth or a long-term gradual decline (Chemical Products Synopsis 1985). The facilities that manufactured or processed tetrachloroethylene in 1993 are listed in Table 4-1 (TR193 1995). Toxics Release Inventory (TRI) data should be used with eaution since only certain types of facilities are required to report. This is not an exhaustive list. 

The 1995 Directory of Chemical Producers in the United States lists three major manufacturers of tetrachloroethylene with a total annual capacity of 490 million pounds (SRI 1995). 

According to the Toxics Release Inventory (TRl), an annual compilation of information on the release of toxic chemicals by manufacturing and processing facilities, an estimated total of at least 11.2 million pounds of tetrachloroethylene was released to the air in the United States in 1993 (TR193 1995). This accounts for about 99% of all tetrachloroethylene released to the environment and is a reduction from a level of 32.2 million pounds which was reported in 1988 (TR188 1990). The number... 

Environmental releases of tetrachloroethylene also occur at sites of its manufacture and at sites of production of other chlorohydrocarbons (such as ethylene dichloride and methylene chloride) in which tetrachloroethylene is formed as a by-product (Weant and McCormick 1984). Tetrachloroethylene emissions to the atmosphere may occur at sites used in disposing the chemical (EPA 1985d), including incineration facilities for municipal and hazardous waste (Oppelt 1987). Tetrachloroethylene can also be released to the atmosphere from the ocean where it is produced by some macroalgae (Abrahamsson et al. 1995). 

According to TRI, an estimated total of at least 23,000 pounds of tetrachloroethylene was released to water from manufacturing and processing facilities in the United States in 1988 (TRI88 1990). The level reported in 1993 was 10,152 poimds, about 0.09% of the total release to the environment (TRI93 1995). The number of reporting facilities in each state and the ranges within which individual facilities reported their releases are shown in Table 5-1. The TRI data listed in Table 5-1 should be used with caution since only certain types of facilities are required to report. This is not an exhaustive list. 

Chlorinated hydrocarbons, containing one or two carbon atoms, constitute a significant fraction of the hazardous substances from industrial, domestic, and agricultural sources. In part, this is due to their high levels of production. Over five million tonnes of 1,2-dichloroethylene (1,2-DCE) are produced annually for use as a solvent and chemical intermediate [1]. Vinyl diloride (VC) is also produced in large amoimts (over three million tonnes annually) for the manufacture of polyvinyl chloride [1]. The solvents tetrachloroethylene (PCE), trichloroethylene (TCE), 1,1,1-trichloroethane (TCA), 1,1-dichloroethylene (1,1-DCE), 1,2-dichloroethane (1,2-DCA), and carbon tetrachloride (CT) have a combined annual production of over 6 million tonnes [1]. Since 1970, annual U.S. production of dichloromethane (DCM) has ranged from 212 to 286 million kg, with the principal application being paint removal [2]. 

Chemical companies made HCB as a byproduct of manufacturing other chlorinated hydrocarbons such as carbon tetrachloride, tetrachloroethylene, and trichloroethylene. In the 1970s, for example, these processes accounted for 89% of the HCB manufactured in the United States [85]. HCB can also be produced directly by treating isomers of hexachlorocyclohexane with sul-furyl chloride or by reacting benzene or chlorobenzenes with chlorine [85]. 

Example 1 Tetrachloroethylene, C2CI4, used mainly as a dry cleaning fluid, also serves as a source of chlorine atoms (nuclei) for the detection of neutrinos (page 535). The manufacture of CjCU from acetylene, CjHj, is summarized as... 

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