Method for the continuous separation of mixtures comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water by means of distillation

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 K; (ii) feeding a bottom fraction from the first distillation column to a second distillation column K, wherein water and an organic product are separated off at a top of the second distillation column at a top temperature of 45 to 198° C. and a pressure in the range from 0.1 to 15 bar; (iii) feeding a bottom fraction from the second distillation column to a third distillation column K, wherein morpholine and an organic product having a boiling point of 190° C. (1.013 bar) are separated off at a bottom of the third distillation column, and (iv) feeding the morpholine-comprising stream from the third distillation column to a fourth column K, wherein morpholine is separated off at a side offtake of the fourth column, an organic product having a boiling point of ≦128° C. (1.013 bar) is separated off at a top of the fourth distillation column and an organic product having a boiling point of ≧128° C. (1.013 bar) is separated off at a bottom of the fourth distillation column.