Processes for the continuous fractional distillation of a mixture comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water from a reaction of diethylene glycol (DEG) with ammonia, the process comprising: (i) separating off ammonia from the mixture at a top of a first distillation column K10; (ii) feeding a bottom fraction from K10 to a second distillation column K20 in which water and organic products are separated off at the top at a temperature at the top in the range from 45 to 198° C. and a pressure in the range from 0.1 to 15 bar, (iii) feeding a bottom fraction from K20 to a third distillation column K30, wherein the column K30 is a dividing wall column (DWC) which preferably has a dividing wall (DW) in the longitudinal direction of the column to form an upper combined column region (1), a lower combined column region (6), an inflow part (2, 4) having an enrichment section (2) and a stripping section (4), and also an offtake part (3, 5) having an enrichment section (3) and a stripping section (5), with the bottoms from K20 being fed in in the upper or middle third of the inflow part (2, 4), based on the number of theoretical plates of the inflow part, ADG and organic products having a boiling point of >190° C. (1.013 bar) being discharged at the bottom, organic products having a boiling point of ≦128° C. (1.013 bar) being discharged at the top and MO being discharged from the middle or lower third of the offtake part (3, 5) (side offtake), based on the number of theoretical plates of the offtake part.