The present invention relates to a process for distillative separation of part or all of an imine (III) selected from the group consisting of aminohexylideneimine, tetrahydroazepine or adducts thereof, from a mixture (II) comprising an amine (I) selected from the group consisting of hexamethylenediamine and 6-aminocapronitrile, and said imine (III), which comprises adding to the distillation mixture a compound (IV) which is inert toward said amine (I) under distillation conditions and whose boiling point is above the boiling point of said amine (I) under said distillation conditions to obtain, after the distillation, a mixture (VI) comprising essentially said compound (IV).