Patent DE-19613551-A1 (DE)
Title: Aromatic poly:amine mixture integrated production and fractionation
Inventor: KNOEFEL HELMUT DR
IPC: C07C209/86
Filed: 1996-04-04
Abstract: A process for the production of aromatic polyamine mixtures with integrated fractionation and/or purification comprises reacting aryl amines with carbonyl compounds, especially formaldehyde in the presence of acid catalysts and water (at least in the last stage of the rearrangement), and optionally in series with a separate "aminal stage" to form N,N'- disubstituted condensation products in the absence of catalyst and optionally in presence of hydrophobic solvents.    In this process,  (a) the reacted mixture (01) is (e) taken to multi-stage counter-current extraction (stage C-2) with an organic phase containing solvents, arylamine and possibly small amounts of polyamine, optionally  (b) after adding arylamine and/or water and/or strong acid (as salts of arylamine and possibly polyamine), preferably in the form of a recycled aqueous phase (04, 05 and/or 07), optionally  (c) after adding hydrophobic solvent which may contain arylamine and/or polyamine, and optionally  (d) after a stage (C-1) in which any organic phase is separated off; the aqueous phase obtained (04, which is free from polyamine) is  (h) at least partly returned to the reaction process and unrecycled aqueous phase as in (b) is used, optionally  (f) after removing water from (04) by distillation in stage (C-4) and optionally (g) after removing amine and increasing the level of protonation by extraction in stage (C-3); (i) the organic phase (09) from (C-2) and any organic phase (10) from (C-1) is taken to (D-2) for multi-stage counter-current extraction with an aqueous phase (12) containing water, strong acid (as ammonium salt), arylamine and possibly polyamine, the composition of this phase being adjusted to give the required controlled partition of polyamine between the resulting organic (14) and aqueous (13) phases and the required composition of the resulting polyamine fraction; the organic phase (14) from (D-2), optionally  (k) after removing some for recycling (preferably via an extraction stage D-1), is  (l) taken to a preferably multi-stage distillation stage (E-3)/(E-4) via a washing and/or neutralisation stage, and separated into first distillate fraction(s) (15) containing solvent and possibly arylamine, possibly a second fraction containing arylamine and possibly solvent, and a residue (17) mainly containing polyamine; the aqueous phase (13) from (D-2) is taken, optionally  (m) via an intermediate extraction stage (D-3),  (n) to a further stage (D-4) for counter-current extraction with an organic phase (18) containing solvent and arylamine, so that polyamine is transferred to the resulting organic phase (19); the polyamine-free aqueous phase is (r) returned to (D-2), optionally  (o) after distillation of some of the water, optionally  (p) after removing amine and increasing protonation and optionally  (q) after passing through extraction stage (D-1), and the organic phase (19) is taken via a washing and/or neutralisation stage to optionally multi-stage distillation (F-3) and separated into fraction(s) containing solvent and arylamine and a second polyamine fraction (20).