Inventors:
Clark Graybill - Lake Charles LA, US
Stephen Lester - Pittsburgh PA, US
International Classification:
C07C017/358
Abstract:
Describes a method for recovering trans-1,2-dichloroethene from a liquid feed composition comprising both the cis- and trans-isomers of 1,2-dichloroethene and contaminating amounts of other chlorinated hydrocarbons, e.g., lower alkyl chlorinated hydrocarbons, such as CCchlorinated hydrocarbons. In one of the described methods, the liquid feed composition is introduced into a first distillation column wherein the stereoisomers and chlorinated hydrocarbons more volatile than the stereoisomers are removed as overhead and charged to a second distillation column . In column , the stereoisomers are separated from the more volatile chlorinated hydrocarbons, and a bottoms fraction comprising the stereoisomers are charged to a reaction distillation column wherein the cis-isomer, is isomerized to the trans-isomer in the liquid phase and in the presence of an organic free-radical initiator, e.g., an azonitrile initiator. Substantially pure trans-1;2-dichloroethene is recovered as overhead from reaction distillation column