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 C
1-
C
2
chlorinated hydrocarbons. In one of the described methods, the liquid feed composition is introduced into a first distillation column
10
wherein the stereoisomers and chlorinated hydrocarbons more volatile than the stereoisomers are removed as overhead
12
and charged to a second distillation column
20
. In column
20
, the stereoisomers are separated from the more volatile chlorinated hydrocarbons, and a bottoms fraction
24
comprising the stereoisomers are charged to a reaction distillation column
30
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
32
from reaction distillation column
30.
描述了一种从液体进料中回收trans-
1,2-二氯乙烯的方法,该液体进料包括
1,2-二氯乙烯的顺反异构体和其他
氯化碳氢化合物的污染物,例如低碳烷基
氯化碳氢化合物,如C1-C2
氯化碳氢化合物。在其中一种描述的方法中,将液体进料引入第一蒸馏柱10中,其中立体异构体和比立体异构体更挥发的
氯化碳氢化合物作为顶部12去除并充入第二蒸馏柱20中。在柱20中,立体异构体与更挥发的
氯化碳氢化合物分离,底部馏分24包括立体异构体,被充入反应蒸馏柱30中,在液相和有机自由基
引发剂的存在下,例如偶氮腈
引发剂中,顺异构体异构为反异构体。从反应蒸馏柱30中以过头气体32的形式回收基本纯的trans-
1,2-二氯乙烯。