Disclosed are processes for an isomerization reaction between (E)1-chloro-3,3,3-trifluoropropene and (Z)1-chloro-3,3,3-trifluoropropene. Some of the disclosed processes include the step of contacting a feed stream with a heated surface, where the feed stream includes (E)1-chloro-3,3,3-trifluoropropene, (Z)1-chloro-3,3,3-trifluoropropene or mixtures thereof. The resulting product stream includes (E)1-chloro-3,3,3-trifluoropropene and (Z)1-chloro-3,3,3-trifluoropropene, where the ratio of (E) isomer to (Z) isomer in the product stream is different than the ratio feed stream. The (E) and (Z) isomers in the product stream may be separated from one another.