Preparation of hexamethyleneimine

A process for the preparation of hexamethyleneimine by hydrogenating .epsilon.-caprolactam over a copper/aluminum oxide hydrogenation catalyst which is fixed or forms a fluidized bed, said catalyst being formed by precipitating, at pH 8 to 9.5 and a temperature of from 60.degree. to 90.degree. C.

• a. an aqueous dilute solution of copper and aluminum salts capable of being precipitated by carbonate, the copper and aluminum being present in said solution in an atomic ratio of m:6, m being a number between 2 and 6, with
• b. an aqueous alkali metal carbonate or bicarbonate solution, the atomic concentration of alkali being about twice the concentration of copper and aluminum in said solution,
• whereby a composition is obtained of the formula
• Cu.sub.m Al.sub.6 (CO.sub.3).sub.0.5m O.sub.3 (OH).sub.m+12,
• having the above definition, and thereafter drying and annealing the precipitate at 350.degree. to 600.degree. C., wherein the reaction is carried out in the gas phase and the caprolactam is vaporized in the stream of hydrogen gas, in an amount such that at a hydrogenation reaction temperature of from 170.degree. to 250.degree. C. and under a working pressure of 10 bar or less the degree of saturation with caprolactam is less than 80%, the residence time being less than one minute.