Verfahren zur Herstellung polychlorierter AEthane

摘要

1,237,752. Chloroethylenes and chloroethanes. CENTRAL GLASS CO. Ltd. 30 Aug., 1968 [30 Aug., 1967; 16 Dec., 1967; 2 Feb., 1968; 3 Feb., 1968], No. 41621/68. Heading C2C. Polychlorinated ethanes having at least three chlorine atoms in their molecules are produced by the liquid phase chlorination of a mixture of CH 2 Cl-CH 2 Cl and at least one mono- or dichloroethylene, chlorine being passed through the mixture in excess of the amount required to add to the chloroethylene. The chloroethylene may be contacted with a gas containing molecular oxygen before being introduced to the chlorination reaction system. The polychlorinated ethanes may be pyrolysed to di- and polychloroethylenes, optionally after the removal of dichloroethane. The pyrolysis may be carried out in the presence of a catalyst, e.g. BaCl 2 on active carbon, and accelerators such as O 2 , Cl 2 , Br 2 , CCl 4 or C 2 Cl 6 may also be added. Cis- and trans-1,2-dichloroethylenes may be separated from the pyrolysis product and recycled to the chlorination step. If desired, some or all of the 1,1-dichloroethylene in the pyrolysis product may also be recycled to the chlorination step. Alternatively, the pyrolysis product is reacted with hydrogen chloride, which may include that evolved during the pyrolysis, in the liquid phase to convert selectively the 1,1-dichloroethylene to 1,1,1-trichloroethane. This reaction may be conducted in the presence of a Friedel-Crafts catalyst, e.g. FeCl 3 or AlCl 3 . Trichloroethylene and tetrachloroethylene may be obtained as products by separation from the pyrolysis product prior to the hydrochlorination reaction or from the hydrochlorination reaction product. Cis- and trans-1,2-dichloroethylenes may be separated from the hydrochlorination reaction product and recycled to the chlorination reaction. Specified products of the chlorination reaction are CH 2 Cl-CHCl 2 , CHCl 2 ,-CHCl 2 , CH 2 Cl- CCl 3 and CHCl 2 -CCl 3 . Specified products of the pyrolysis reaction are CHCl=CHCl, CH 2 = CCl 2 , CHCl=CCl 2 and CCl 2 = CCl 2 .