GB846517A - Preparation of tri- and tetrachlorethylene - Google Patents

Abstract

1,2-Dichloroethylene is chlorinated in a single stage to produce trichloroethylene and tetrachloroethylene in relative molar proportions of about 0-80% trichloroethylene by passing through a fluidised solid chlorination-dehydrochlorination catalytic mass maintained at 350-450 DEG C., a mixture containing chlorine and dichloroethylene in proportions necessary for the continuous total fixation of chlorine by formation of the desired relative quantities of trichloroethylene and tetrachloroethylene. Preferably the molar ratio of chlorine to 1,2-dichloroethylene is 1-2:1; to obtain 2 molecules of tetrachloroethylene to 1 molecule of trichloroethylene, the molar ratio of chlorine to 1,2-dichloroethylene is about 1,67:1; and to obtain 2 molecules of trichloroethylene to 1 molecule of tetrachloroethylene, this ratio is about 1,33:1; 1-10% of the catalytic mass is advantageously withdrawn periodically and replaced by fresh catalyst; suitable catalytic masses are active carbon, fuller's earth and cristalba, and may be impregnated with cupric chloride and/or barium chloride. The reacting mixture may contain more highly chlorinated products in quantity equal to that passing out of the reaction zone (such as tetrachloroethane and pentachloroethane). Specification 673,565 is referred to.