Process for the preparation of aromatic polyamines

Abstract

The instant invention is directed to a novel process for the production of aromatic polyamines. In one embodiment, the process comprises (A) condensing an aromatic amine with formaldehyde in the presence of a hydrophobic solvent and in the absence of an acid catalyst to produce a precondensate mixture containing the corresponding N,N'-disubstituted aminals, (B) removing substantially all the water from said precondensate mixture to produce a first organic phase, (C) mixing said first organic phase with an aqueous solution containing an acid catalyst thereby producing a first two-phase mixture, (D) subjecting said first two-phase mixture to a first rearrangement reaction wherein a mono-N-substituted aminal is formed and wherein a second two-phase mixture is produced, (E) separating said second two-phase mixture into a second organic phase and a first aqueous phase, (F) subjecting said first aqueous phase to at least one more rearrangement reaction thereby producing an aqueous condensation mixture containing said aromatic polyamines, (G) extracting said aqueous condensation mixture with a hydrophobic solvent to provide a solvent phase and a second aqueous phase comprising an aqueous solution containing the acid catalyst as an amine salt of said aromatic amine, and of said aromatic polyamines, (H) recovering aromatic polyamines from said solvent phase, and (I) returning said second aqueous phase to step (C).