It was attempted to develop a process for the synthesis of trichloroethylene and perchloroethylene from 1, 1, 2-trichloroethane, a by-product produced in vinyl chloride manufacturing process. The investigation was concentrated on the gas phase chlorination in the temperature range of 200-350 ℃ and for the ratio of chlorine to 1, 1, 2-trichloroethane from 0.45 to 1.00. The reactor and other equipments were fabricated with nickel and nickel alloys which are highly resistant to high temperature chlorine and hydrogen chloride gas. Since gas phase chlorination is a free radical reaction, many related chlorohydrocarbones such as di-, tri-, per-chloroethylenes, tetra-, penta-, hexa-chloroethanes, and other heavies are produced together. Trichloroethylene was produced preferably at low temperature and low chlorine ratio whereas high temperature was preferred for the production of perchloroethylene. Dichloroethylenes were decreased with increasing chlorine ratio and heavies were decreased with reaction temperature. Since trichloroethylene and perchloroethylene were produced simultaneously much effort was focused on the investigation of the reaction conditions controlling the product ratio to meet the demand of both products.