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Vinyl chloride is a colorless gas at normal temperature and pressure, with a boiling point of -13.4°C. Its molecule contains double bonds, and its chemical structural formula is CH2=CH-CL. Industrially, vinyl chloride is transported in liquid form and is not allowed to be in contact with the human body. Vinyl chloride is an OSHA controlled substance. V. Regnault first discovered vinyl chloride in 1835. In 1911, Klaett and Rollet Vinyl chloride was synthesized from acetylene and hydrogen chloride. In 1913, Griesim-Elektron used a mercury chloride catalyst to develop this synthesis. In 1931, the process of synthesizing vinyl chloride from acetylene and hydrogen chloride was first industrialized in Germany using mercury chloride as a catalyst. In 1933, the United States developed a process for producing vinyl chloride by ethylene. Ethylene was directly chlorinated to produce dichloroethane, and then dichloroethane molecules were dehydrochlorinated under the action of alkali to obtain vinyl chloride. In 1950, the cracking of dichloroethane was developed to obtain vinyl chloride, which was combined with carbide acetylene and vinyl chloride to form a combined vinyl chloride process. Nowadays, another common method for producing vinyl chloride in China is the oxychlorination of ethylene using petroleum ethylene as raw material to produce vinyl chloride. After more than 40 years of development, my country's vinyl chloride industry entered a period of rapid growth in 2004. There are 9 companies with a production capacity of more than 200,000 tons/year, and 23 companies with a production capacity of more than 100,000 tons/year. Currently, there is a huge gap in my country's market demand. The main use of vinyl chloride is to produce polymers. Polyvinyl chloride is an important thermoplastic resin. After processing and modification, it can be made into hard, soft, and foam plastic products. After special processing, it can be made into sanitary food packaging materials. The polymer of vinyl chloride can also be made into fiber, usually called chlorine fiber. In addition, vinyl chloride can also be made into organic raw materials, vegetation and other organic chlorides. 1.1 Physical Properties of Vinyl Chloride Vinyl chloride is a colorless, easily flammable gas with a special aroma in its normal state. It can be easily converted into a liquid under slightly pressurized conditions. Vinyl chloride is slightly soluble in water. At 25°C, 0.11g of vinyl chloride can be dissolved in 100g of water. ； The solubility of water in vinyl chloride: at -15°C, 100g of vinyl chloride can dissolve 0.03g of water. Vinyl chloride is soluble in hydrocarbons, propylene, ethanol, chlorine-containing solvents such as dichloroethane, and a variety of organic solvents. Typical physical parameters of vinyl chloride are shown in Table 1-1. Vinyl chloride is a gas at normal temperature, and is transported in a liquid state at 0.2-1.5MPa during the production of vinyl chloride. The polymerization process mostly uses kettle reactors and operates intermittently. Therefore, quite complex pipelines need to be installed in the production plant to transport them between several pressure vessels. There is a risk of vinyl chloride leaking from the pressurized equipment to the outside. In addition, the polymerization of vinyl chloride is not completely converted into polymer. After polymerization, approximately 10%-20% of the monomer of the original input needs to be removed. Before 1960, people recognized that vinyl chloride was an explosive gas that had certain * * sex. During the 1960s, a small number of people in polyvinyl chloride manufacturing plants were found to have an orthopedic condition called acroosteolytic disease (AOL). In the early 1970s, Maltoni studied the wide range of vinyl chloride that can induce tumors. In 1974, several cases of hepatic angiosarcoma were discovered in the vinyl chloride factory of BF Goodrich Company in the United States, which attracted world attention and made people realize that vinyl chloride appears to be a harmful substance that can cause cancer. Table 1-1 Physical properties of vinyl chloride Physical properties Numerical physical properties Numerical molecular weight 62.499 Standard free energy of formation KJ/mol 51.5 Melting point ℃ -153.8 Vapor pressure KPa Boiling point ℃ -13.4 -30 ℃ 50.7 Specific heat capacity -20 ℃ 78.0 20℃ Steam 858 -10 ℃ 115 20℃ Liquid 1352 0 ℃ 164 Critical temperature ℃ 156.6 Viscosity critical pressure MPa 5.60 -40 ℃ 0.3388 Critical volume㎝3/mol 169 -30 ℃ 0.3028 Compression factor 0.265 -20 ℃ 0.2730 Eccentricity factor 0.122 -10 ℃ 0.2481 Dipole moment C﹒ m 5.0 * 10 Explosion limit in air % 4~22 Heat of fusion, J/g 75.9 Natural temperature ℃ 472 Heat of vaporization, J/g 330 Flash point (open cup) ℃ -77.75 Standard heat of formation KJ/mol 35.18 Liquid density g/cm3 (-14.2℃) 0.969 1.2 Chemical properties of vinyl chloride Vinyl chloride is an unsaturated compound containing chlorine atoms in the molecule. Due to the existence of double bonds, vinyl chloride can undergo a series of chemical reactions. The most important chemical reactions in industrial applications are its homopolymerization and copolymerization. (1) Homopolymerization reaction: The double bonds in the vinyl chloride molecule are very active. In the presence of light, heat, organic peroxides and other initiators, the double bonds open and homopolymerization occurs, nCH2=CH2→ —(CH2—CH2)n—. Polymerization methods used in industry include suspension polymerization, emulsion polymerization, solution polymerization and bulk polymerization. These polymerization methods are all applicable to vinyl chloride. Suspension polymerization is the most commonly used polymerization of vinyl chloride. (2) Copolymerization In order to improve the performance of polyvinyl chloride resin, other monomers can be added during the polymerization process of vinyl chloride to form a copolymer product. Vinyl chloride can copolymerize with a variety of monomers. (3) Substitution reaction of carbon-chlorine bond. For nucleophilic substitution reactions. Vinyl chloride is very inert compared to alkyl halides. However, recent work has shown that chlorine exchange reactions can occur rapidly in the nucleophilic state in the presence of palladium and other transition metals. (4) Oxidation reaction. Ethylene chloride is oxidized in the gas phase to obtain 74% (vol) CLCHO and 25% (vol) CO, with a conversion rate of 30%-32%. (5) Addition reaction. Vinyl chloride can undergo chlorination (6) cleavage reactions along ionic or radical pathways. For thermal decomposition reactions, vinyl chloride is more stable than saturated chlorinated hydrocarbons. Therefore, one of the major reactions used in the production of vinyl chloride is the thermal dehydrochlorination of 1,2-dichloroethane. This post was last edited by flyyi61 on 2009-2-2 13:24 ]