Patent ID: 8884015

Claim:
A process for the preparation of a mono-N-alkylpiperazine of the formula I in which R 1 is C 1 - to C 5 -alkyl or 2-(2-hydroxyethoxy)ethyl, comprising reacting diethanolamine of the formula II (DEOA) with a primary amine of the formula H 2 N—R 1 (III) in the presence of hydrogen and a supported, metal-containing catalyst, wherein a catalytically active mass of the catalyst, prior to its reduction with hydrogen, comprises oxygen-containing compounds of aluminum, copper, nickel and cobalt and, in the range from 0.2 to 5.0% by weight, one or more oxygen-containing compounds of tin, calculated as SnO, and wherein the reaction is carried out in the liquid phase at an absolute pressure in the range from 95 to 145 bar.