Copper catalyzed disproportionation of benzylamine methyl derivatives

Abstract

The reactions of benzylamine methyl derivatives on an alumina supported copper catalyst have been studied in the temperature range of 500 to 530 K. Depending on the reactant amine (N,N-dimethylbenzylamine, N-methylbenzylamine, benzylamine) either disproportionation or hydrogenolysis was the dominant reaction. The disproportionation occured with methyl as well as with benzyl radical migration. The hydrogenolysis resulted in lower amines or in hydrocarbon formation. Using the copper catalyzed amination of benzyl alcohol with dimethylamine as an example, it is shown that under the conditions generally used for amination, these amine reactions are strongly inhibited by the reactant alcohol. A lowering of the benzyl alcohol concentration by dilution of the reactant mixture with nitrogen led to a significant decrease in selectivity to N,N-dimethylbenzylamine.