A continuous process for the preparation of monoethanolamine,
diethanolamine and triethanolamine by reacting ammonia and ethylene oxide
in liquid phase in the presence of water as catalyst in a pressure column
is proposed, where, as a result of the heat of the reaction, some of the
ammonia evaporates, condenses at the head of the column and is again
charged to the column, the reaction mixture at the bottom end of the
pressure column is drawn off and then separated, the pressure column is
constructed as a reactive distillation column (I) with evaporator at the
bottom (S) and where, by means of inputting energy via the evaporator at
the bottom (S), the weight ratio of monoethanolamine to diethanolamine to
triethanolamine is controlled and, via the ratio of ammonia to ethylene
oxide in the feed to the reactive distillation column (I), the ammonia
proportion in the bottom product from the reactive distillation column (I)
is controlled.
