Distillation of hydrocarbon chlorides containing predominantly trichloroethylene and perchloroethylene produced by oxychlorination reactions

1,104,580. Separation of trichloroethylene and perchloroethylene from chlorinated hydrocarbon mixtures by distillation. PITTSBURGH PLATE GLASS CO. 16 Nov., 1966 [13 Dec.. 1965], No. 51318/66. Heading B1B. Trichloroethylene and perchloroethylene are separated from chlorinated hydrocarbon mixtures, such as mixtures produced by the catalytic oxychlorination of ethane, ethylene or 1, 2-dichloroethane, 'by submitting the mixture, after dehydration, to fractional distillation in five columns connected together as shown and operated under such conditions of temperature and pressure that the feed stream is separated in column 2 into an overhead fraction which is rich in trichloroethylene and a bottoms fraction which is rich in perchloroethylene; the overhead fraction from column 2 is freed in column 7 from material boiling below trichloroethylene and is then freed from higher-boiling material in column 15 from which substantially pure trichloroethylene is obtained as overhead product; and the bottoms fraction from column 2 is freed in column 4 from material boiling above perchloroethylene, and is then fractionated in column 9 to obtain substantially pure perchloroethylene as bottoms product. The bottoms fraction from column 15 is recycled to the feed inlet of column 2. The overhead fractions from columns 7 and 9 are returned to the reactor in which the chlorinated hydrocarbon mixture is produced. In a modified process, column 15 is eliminated, and purified trichloroethylene is then obtained as bottoms product from column 7.