Abstract: An improved process for the production of chloroprene, which is the critical monomer constituent of neoprene rubbers, and of 2,3-dichlorobutadiene-1,3, which often is copolymerized with chloroprene to provide better low temperature properties of the resulting elastomer, involves dehydrochlorination of a chlorinated hydrocarbon such as 3,4-dichlorobutene-1, 2,3,4-trichlorobutene-1, or 1,2,3,4-tetrachlorobutane, with an aqueous mixture of sodium hydroxide and sodium chloride having the composition of chlor/alkali cell liquor; separation of the organic phase from which the desired product, chloroprene or 2,3-dichlorobutadiene-1,3, is recovered by distillation; and recirculation of the aqueous (brine) phase to the electrolysis apparatus, from which the sodium hydroxide-sodium chloride liquor is returned to the dehydrochlorination step.