Vapour-Phase Substitution of Chlorobenzene with Ammonia Catalyzed by Copper-Exchanged Zeolites

Article abstract of DOI:10.1006/jcat.1994.1186

The nucleophilic substitution of chlorobenzene with ammonia, leading to aniline, was investigated over various copper-exchanged catalysts using vapour-phase reactants.Benzene and diphenylamine were formed as side-products.The zeolites tested (Cu-L, Cu-modernite, Cu-Y, Cu-ZSM-5, and Cu-beta) gave better results than copper-containing silica-alumina, because of the high deactivation rate of the latter.On zeolites Cu-L, Cu-modernite, and Cu-ZSM-5, substitution prevailed: with Cu-modernite and Cu-ZSM-5, aniline selectivities of 90-94percent were obtained.In contrast, reduction towards benzene was pronounced on Cu-beta and especially on Cu-Y.In more detailed studies with Cu-modernite, two deactivation regimes were observed, related to the reaction temperature.With Cu-L, the dehalogenation towards benzene was investigated: it is ascribed to copper reduction, followed by the reduction of chlorobenzene with the copper(0) particles thus obtained.