Ppg Industries Ohio, Inc.

Clark S Graybill

Stephen Robert Lester

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 columnwherein the stereoisomers and chlorinated hydrocarbons more volatile than the stereoisomers are removed as overheadand charged to a second distillation column. In column, the stereoisomers are separated from the more volatile chlorinated hydrocarbons, and a bottoms fractioncomprising the stereoisomers is charged to a reactive distillation columnwherein 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 32 from reactive distillation column

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Lake Charles, LA, United States of America

Clark S Graybill