Abstract From 3, 4, 4-trichloro-3-butenoic acid 3, 3, 4, 4, 4-pentachlorobutanoic, 3, 4, 4, 4- tetrachloro-2-butenoic, and 2, 3, 4, 4-tetrachloro-3-butenoic acids were synthesized. By Friedel &-Krafts reaction from 3, 4, 4-trichloro-3-butenoyl and 3, 3, 4, 4, 4- pentachlorobutanoyl chlorides with aromatic hydrocarbons the corresponding aryl chloroalkyl ketones were prepared. It was established that dehydrochlorination of 2, 2, 3, 3 ...