SU910573A1 - Process for producing 1,1,2-trichloroethane - Google Patents

Description

 one . -,; The invention relates to the chemical industry. 1,1,2-Trichloroethane is used to obtain the valuable monomer, vinylidene chloride, on the basis of which films, plastics, fibers with valuable properties are obtained. A known method for producing 1,1,2-trichloroethane by the chlorination of dichloroethane by chloroforimetry when the process is rather cumbersome and difficult to implement. The closest to the proposed method is to obtain 1,1,2-trichloro ethane by liquid-phase chlorination of nilchloride in the medium of trichloroethane itself at 20-ZO C in the presence of a ferric chloride catalyst and the molar ratio chlorine: vinyl chloride 1; . with an excess of chlorine 02. With this method, the yield of 1,1,2-trichloroethane does not exceed also the by-products used in production — 1,1,2,2-tet |} chloroethane and 1,1-dichloroethane are obtained. The raw trichloroethane obtained by this method contains significant amounts of dissolved chlorine (up to 3.5 kg per ton of trichloroethane), which prevents further processing of the product into vinylidene chloride. To remove dissolved chlorine, the trichloromethane is washed with 2% NaOH solution. In this case, a large amount of polluted organochlorine impurities and inorganic salt of sewage water (up to 5 m per 1 ton of trichloroethane) is formed, which leads to the need to create expensive sewage treatment plants. The purpose of the invention is to increase the yield of trichloroethane and the disposal of wastewater. This goal is achieved by the described method for the preparation of 1,1,2-trichloroethane, which consists in the fact that the liquid-phase chlorination of vinyl chloride 3. 9 in 1,1,2-trichloroethane are conducted with chlorine in the presence of a ferric chloride catalyst at 20-30 ° C at a molar ratio of chlorine and vinyl chloride of 0.8-1.0: 1 with recycling of unreacted vinyl chloride to the beginning of the process. A distinctive feature of the process is to conduct the process at a molar ratio of chlorine and vinyl chloride of 0.8-1: 1 with recycling of unreacted vinyl chloride at the beginning of the process. When practicing the process, the unreacted vinyl chloride dissolved in the reaction mass is separated, for example, by simple distillation, and then the chlorination is returned. Due to an excess of vinyl chloride in the reaction zone, it is possible to significantly reduce the formation of by-products and increase the yield of the target product 1,1,2-trichloroethane jqo 99.999, 5% against 95-97%. There is no dissolved chlorine in the reaction mass after chlorination, which allows to process the resulting trichloroethane without preliminary washing it with aqueous alkali and, therefore, avoiding the formation of wastewater. The invention is illustrated by examples, the results of which are tabulated. The drawing shows a plant for producing 1,1,2-trichloroethane by the proposed method. 3 The installation consists of a dosing system for vinyl chloride and chlorine, a reactor 1 and a stripping column 2. Gaseous chlorine and vinyl chloride from the cylinders flow through the bubblers into a cylindrical glass reactor (volume 75 ml), pre-filled with 1,1, 2-trichloroethane. The required amount of ferric chloride catalyst is formed due to the corrosion of a steel plate (Art. -3 /) 22x8x2 mm in size, immersed in the reaction mass. In the reactor 1, the optimum temperature is maintained at +25 C. A small amount of hydrogen chloride is formed during the side reaction through a reflux condenser. And absorbed by water. 1,1,2-Trichloroethane raw from the reactor overflow enters the Stripping column 2, in a cube which maintain a temperature of 113 ° C. From the top of the column, a pair of vinyl chloride and partially 1,1, 2-trichloroethane is fed into a water cooler and returned to the chlorination reactor 1 after condensation. 1,1,2-trichloroethane with the content of the main substance 99j299, 5 is removed from the cube of the column. % The 1,1,2-trichloroethane obtained by this method of the specified purity does not need additional purification and can be directly used to obtain vinylidene chloride.

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The invention claims A method of producing 1,1,2-trichloroethane by liquid phase chlorine or vinyl chloride with chlorine at a temperature of 20-30 ° C in the presence of a catalyst of ferric chloride in a medium of 1,1,2-trichloroethane, characterized by and with the fact that, in order to increase the yield of the target product and eliminate hazardous wastewater, the process is carried out at a molar ratio of the scientific research institute of chlorine and vinyl chloride equal to

Chlorine

futfi / f chloride

Exhaust gases

absorption 8 0.8-1: 1, with recycling of unreacted vinyl chloride at the beginning of the process. Sources of information taken more attention in the examination 1. Methods of organoelement chemistry, ed. A.N. Nesme, M., Science, 1973, p. 268. 2. Industrial organochlorine products. Handbook ed. L. A. Oshina. M., Himi, 1978, p. 138 (prototype).

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Claims (3)

Claim The method of producing 1,1,2-trichloroethane by liquid-phase chlorination of vinyl chloride with chlorine at a temperature of 20-30 * C in the presence of a ferric chloride catalyst in 1,1., 2-trichloroethane medium, characterized in that, in order to increase the yield of the target product and elimination of harmful wastewater, the process is carried out with a molar ratio of chlorine and vinyl chloride equal to \ 910573 8 0.8-1: 1, with recirculation of unreacted vinyl chloride at the beginning of the process. 5 Sources of information taken into account during the examination 1. Methods of organoelement chemistry, ed. A.N. Nesmeyanova, M. Nauka, 1973, p. 268. 10 2. Industrial organochlorine products. Handbook Ed. L. A. Oshina. M., Chemistry, 1978, p.138 (prototype).