Patent ID: 7575660

Claim:
A process for the distillative separation of aqueous amine solutions from the hydrogenation of nitroaromatic compounds, comprising: a) carrying out distillation in at least two distillation columns connected in series and operated at different pressures, in which at least one of the distillation columns is operated at higher absolute pressures at the column head of about 2 to about 20 bar and at least one of the distillation columns is operated at lower absolute pressures at the column head of about 0.1 to about 10 bar; b) at least partially condensing vapors leaving the distillation column or columns operating at higher pressure and heating the bottom of the distillation column or columns operating at lower pressure with the heat released therefrom; c) feeding the amine solution into a first of the at least two distillation columns connected in series, and at least partially removing bottom product from the first distillation column and feeding the bottom product into the second distillation column, and d) removing purified amine as bottom product from a last distillation column connected in series.