Patent ID: 8030531

Claim:
A process for production of a composition comprising 2,3-dichlorobutadiene-1,3, the process comprising the steps of: A. contacting a composition comprising 1,2,3,4-tetrachlorobutane with an aqueous mixture comprising a base having a K b of at least 10 −9 , at a temperature sufficient to dehydrochlorinate the 1,2,3,4-tetrachlorobutane, thereby forming a first reaction product having at least two phases, 1) a first phase comprising a mixture of a) 2,3-dichlorobutadiene-1,3 and b) a chlorinated byproduct comprising chlorinated butenes other than 2,3-dichlorobutadiene-1,3 and 2) a second phase comprising an aqueous phase; B. separating said first phase from said aqueous phase; C. contacting said first phase, after it has been separated from said aqueous phase, with chlorine having a purity of at least 96% in an amount sufficient to further chlorinate said chlorinated byproduct but insufficient to cause conversion of more than 20% of the 2,3-dichlorobutadiene-1,3 present in said first phase to more highly chlorinated species, thereby producing a second reaction product; and D. isolating from said second reaction product a composition comprising 2,3-dichlorobutadiene-1,3 wherein at least 90 weight percent of said composition is 2,3-dichlorobutadiene-1,3, based on the total weight of said composition.