Abstract: Catalysts for the addition of hydrogen chloride to chloroprene for the preparation of 1,3-dichlorobutene-(2) in the liquid phase, constituting a complex of copper(I)chloride, aqueous hydrochloric acid, hydrogen chloride andA. a pyridine substituted with 1 to 3 alkyl groups on carbon atoms, which alkyl groups contain 1 or 2 carbon atoms, orB. an N,N-dialkyl substituted aniline, the N-substituted alkyl groups being straight chain groups containing 1 to 3 carbon atoms and the aromatic nucleus being optionally substituted with 1 or 2 methyl groups, the C/N atomic ratio in the molecule of the substituted aniline being <14, orC) diethylamine orD) triethylamine orE) the hydrochlorides of the above mentioned nitrogen compounds.