| abstract |
Process for the preparation of a mono-N-alkylpiperazine of the formula I n n n n n n n n n n in which R 1 is C 1 - to C 5 -alkyl or 2-(2-hydroxyethoxy)ethyl,n nby reacting diethanolamine (DEOA) of the formula IIn n n n n n n n n n n with a primary amine of the formula H 2 N—R 1 (III) in the presence of hydrogen and a supported, metal-containing catalyst, where the 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, oxygen-containing compounds of tin, calculated as SnO, and the reaction is carried out in the liquid phase at an absolute pressure in the range from 95 to 145 bar. |