1,2-dichloroethane, manufacture

The process of dichloroethane manufacture was held on the industrial scale cell of filter-press type by electrolysis of waste hydrochloric acid with current up to 25 kA. 

As an example, consider again the manufacture of vinyl chloride. In the first step of this process, ethylene and chlorine are reacted to form dichloroethane ... 

BrCHi CHjBr. A colourless liquid with a sweet odour, m.p. 10°C, b.p. 132°C. Manufactured by passing ethene through bromine or bromine and water at about 20 C. Chemical properties similar to those of 1,2-dichloroethane when heated with alkali hydroxides, vinyl bromide is formed. Used extensively in petrols to combine with the lead formed by the decomposition of lead tetraethyl, as a fumigant for stored products and as a nematocide. 

Significant quantities of ethyl chloride are also produced as a by-product of the catalytic hydrochlorination over a copper chloride catalyst, of ethylene and hydrogen chloride to produce 1,2-dichloroethane, which is used as feedstock in the manufacture of vinyl choride (see Vinyl polymers). This ethyl chloride can be recovered for sale or it can be concentrated and catalyticaHy cracked back to ethylene and hydrogen chloride (25). As the market for ethyl chloride declines, recovery as an intermediate by-product of vinyl chloride manufacture may become a predominant method of manufacture of ethyl chloride. 

There are three general methods of interest for the preparation of vinyl chloride, one for laboratory synthesis and the other two for commercial production. Vinyl chloride (a gas boiling at -14°C) is most conveniently prepared in the laboratory by the addition of ethylene dichloride (1,2-dichloroethane) in drops on to a warm 10% solution of sodium hydroxide or potassium hydroxide in a 1 1 ethyl alcohol-water mixture Figure 12.1). At one time this method was of commercial interest. It does, however, suffer from the disadvantage that half the chlorine of the ethylene dichloride is consumed in the manufacture of common salt. 

In the manufacture of vinyl chloride (VC) by the pyrolysis of dichloroethane (DCE), the reactor conversion is limited to 55 per cent to reduce carbon formation, which fouls the reactor tubes. 

Vinyl chloride (VC) is manufactured by the pyrolysis of l,2,dichloroethane (DCE). The reaction is endothermic. The flow-rates to produce 5000 kg/h at 55 per cent conversion are shown in the diagram (see Example 2.13). 

BPR [By-Product Recycle] A process for recycling the chlorine-containing by products from the manufacture of vinyl chloride, 1,2-dichloroethane, and other chlorinated hydrocarbons. Combustion with oxygen converts 90 percent of the chlorine to anhydrous hydrogen chloride, and 10 percent to aqueous hydrochloric acid. Developed by BASF and licensed by European Vinyl Corp. 

Dichloroethane, 6 253 acrylamide solubility in, l 290t bioremediation substrate, 3 772 chlorocarbon/chlorohydrocarbon of industrial importance, 6 227t in integrated manufacturing process, 6 237t... 

Source Pentachlorobenzene may enter the environment from leaking dielectric fluids containing this compound. Pentachlorobenzene may be present as an undesirable by-product in the chemical manufacture of hexachlorobenzene, pentachloronitrobenzene, tetrachloroenzenes, tetrachloroeth-ylene, trichloroethylene, and 1,2-dichloroethane (U.S. EPA, 1980). 

Chlorinated ethanes and ethylenes comprise ethyl chloride, ethylene dichloride (1,2 dichloroethane), vinyl chloride, trichloroethylene (TCE), perchloroethylene (RCE), and several CFCs. Some of the major uses of these compounds are as degreasing agents, dry-cleaning solvents, building blocks for manufacturing of polymers (e.g., RVC, ethyl cellulose), and raw material for the production of tetraethyl lead and CECs. We discuss ethylene dichloride, trichloroethylene, and perchloroethylene as examples of this group. 

Current occupational exposure to 1,2-dichloroethane in North America occurs predominantly during the manufacture of other chemicals, such as vinyl chloride, where 1,2-dichloroethane is used as an intermediate. In a 1982 National Occupational Exposure Survey by the United States National Institute for Occupational Safety and Health (NIOSH), 28% of employees working with adhesives and solvents were exposed to 1,2-dichloroethane, while between 5 and 9% of workers were exposed to the substance in the medicinals and botanicals, biological products, petroleum refining and organic chemicals industries, and in museums and art galleries (United States Department of Labor, 1989). 

The history of polysulfides began over 150 years ago. In 1838 chemists in Switzedand reported that the reaction of chloraetherin (1,2-dichloroethane) with potassium polysulfide gaveambivalent a rubbery, intractable, high sulfur semisolid. Subsequently there were reports of similar products obtained by various methods, but the first useful products were developed from studies in the late 1920s. This led to the formation of Thiokol Corp. which began production of the ethylene tetrasulfide polymer Thiokol A in 1928, the first synthetic elastomer manufactured commercially in the United States. One of the first successful applications of Thiokol A [14807-96-6] was for seals where its resistance to solvents justified its relatively high price. 

Demonstration of the technical feasibility of producing mixtures of acetylene and ethylene by pyrolysis of hydrocarbons (Wulff process or Kureha process) has led to the manufacture of vinyl chloride from such mixtures. The acetylene component reacts selectively with hydrogen chloride to form vinyl chloride, the residual ethylene is converted to dichloroethane, and the latter is cracked to vinyl chloride, with the resulting hydrogen chloride being recycled. However, this type of process has not achieved the industrial importance of the all-ethylene type of process. 

Consider the conversion of dichloroethane to vinyl chloride, the starting material for manufacturing poly(vinyl chloride) (PVC) plastics ... 

Approximately 10 million tons of 1,2-dichloroethane are manufactured each year in the United States by the reaction of ethylene with chlorine. The process is the first step in making PVC [polyfvinyl chloride)] plastics. 

Ethylene dichloride (1,2-dichloroethane, CH2C1CH2C1), a colorless toxic liquid (boiling point 84°C, density 1.2560, flashpoint 13°C) is manufactured by two methods. 

Dichloroethane is produced commercially through the reaction of hydrogen chloride and vinyl chloride at 20°-55°C in the presence of an aluminum, ferric, or zinc chloride catalyst (Grayson 1978). Other production methods include the direct chlorination of ethane, the reaction of PCI s with acetaldehyde as a by-product during the manufacture of chloral (Browning 1965), and as intermediate in the production of vinyl chloride and 1,1,1-trichloroethane by photochlorination (Windholz 1983). 

Major companies producing 1,1-dichloroethane within the United States include PPG Industries, Inc., Continental Oil Company, and Vulcan Materials, all based in Louisiana, and Dow Chemical located in Texas. Each of these companies manufactures 1,1-dichloroethane primarily to be used as an intermediate in the manufacture of 1,1,1- trichloroethane. 

NIOSH (1978) noted that there was a large potential for exposure to 1,1-dichloroethane in the workplace during its use as a dewaxer of mineral oils, extractant for heat- sensitive substances, or fumigant, and in the manufacture of vinyl chloride and high-vacuum rubber and silicon grease. 

Zweidinger et al. (1982) and Wallace et al. (1982) conducted a study of the levels of 1,1 -dichloroethane in the inhaled and exhaled air and drinking water of college students in Texas and North Carolina. Low levels (<0.49 ppb) of 1,1-dichloroethane were found in the personal air quality monitors of the Texas students, whose campus bounded a petrochemical manufacturing area, but none was detected in the exhaled breath samples. 1,1-Dichloroethane was not detected in the breathing zone air of the North Carolina students. 

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