Patent ID: 8981093
Filing Date: 2015-03-17
Classification: C07C,C07D

Abstract:
1. A process for preparing piperazine of the formula I by reacting diethanolamine (DEOA) of the formula II with ammonia in the presence of hydrogen and a supported, metal-containing catalyst, wherein the catalytically active mass of the catalyst, prior to its reduction with hydrogen, comprises a) oxygen-containing compounds of cobalt, b) 0.2 to 5.0% by weight of oxygen-containing compounds of tin, calculated as SnO, c) 15 to 80% by weight of oxygen-containing compounds of aluminum, calculated as Al d) 1.0 to 20% by weight of oxygen-containing compounds of copper, calculated as CuO, and e) 5.0 to 35% by weight of oxygen-containing compounds of nickel, calculated as NiO; wherein the reaction is carried out in the liquid phase at an absolute pressure in the range from 160 to 220 bar, a temperature in the range from 180 to 220° C., wherein the molar ratio of ammonia to DEOA is from 5 to 25, and wherein hydrogen is present at from 0.2 to 9.0% by weight based on the total weight of DEOA and ammonia.