The following new compounds were isolated from the vapor phase chlorination of butyne-1, butyne-2, and pentyne-1: 1,1,2,2-tetrachlorobutane, 2,2,3,3-tetra chlorobutane, 1,1,2,2-tetrachloropentane,trans-1,2-dichloro-1-butene,trans-2,3-dichloro-2-butene, andtrans-1,2-dichloro-1-pentene. Dehydrochlorination of 1,1,2,2-tetrachlorobutane and 1,1,2,2-tetrachloropentane gave 1,1,2-trichloro-1-butene and 1,1,2-trichloro-1-pentene respectively. Partial dechlorination of 1,1,2,2-tetrachlorobutane and 1,1,2,2-tetrachloropentane gavecisandtransisomers of 1,2-dichloro-1-butene and 1,2-dichloro-1-pentene respectively. 2,2,3,3-Tetrachlorobutane gave chieflytrans-2,3-dichloro-2-butene. 1,1,1,2,2-Pentachlorobutane and 1,1,1,2,2-pentachloropentane were prepared by chlorination of 1-chloro-1-butyne and 1-chloro-1-pentyne respectively.