Patent DE-19613552-A1 (DE)
Title: Integrated production and fractionation of aromatic poly:amine mixtures
Inventor: KNOEFEL HELMUT DR
IPC: C07C209/86
Filed: 1996-04-04
Abstract: A process for the production of aromatic polyamine mixtures (I) with integrated fractionation and/or purification, by reacting aryl amines (II) with carbonyl compounds, especially formaldehyde (III) in presence of acid catalysts (IV) 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 (IV) and optionally in presence of hydrophobic solvents (V). 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 (V), (II) and possibly small amounts of (I), optionally (b) after adding (II) and/or water and/or strong acid (as salts of (II) and possibly (I)), preferably in the form of a recycled aqueous phase (04, 05 and/or 07), optionally (c) after adding hydrophobic solvent (V) which may contain (II) and/or (I), 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 I), 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), is (h) at least partly extracted in stage C-5 using a polyamine-containing organic phase (29) comprising part of the organic phase (11) and/or at least part of organic phase (14) taken through prior stage D-1, then the resulting polyamine- enriched aqueous phase (30) and any aqueous phase(s) not taken through (C-5) are returned to the reaction, while any of phase (04) and/or (07) not returned to the process is used as in (b); (i) the polyamine-reduced organic phase (31) from C-5 is returned to the reaction process and/or used as in (c) and/or used as in (e) as part extractant phase in C-2; (k) 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), (II) and possibly (I), the composition of this phase being adjusted to give the required controlled partition of (I) 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 (l) after removing some for recycling (preferably via an extraction stage D-1), is (m) 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 (V) and possibly (II), possibly a second fraction containing (II) and possibly (V), and a residue (17) comprising the first polyamine fraction (I); the aqueous phase (13) from (D-2) is taken, optionally (n) via an intermediate extraction stage (D-3), (o) to a further stage (D-4) for counter-current extraction with an organic phase (18) containing (V) and (II), so that polyamine (I) is transferred to the resulting organic phase (19); the polyamine-free aqueous phase is (s) returned to (D-2), optionally (p) after removing amine and increasing protonation in another extraction stage, optionally (q) after distillation of water and optionally (r) after passing through extraction stage (D-1), and the organic phase (19) from D-4 is taken via a washing and/or neutralisation stage to optionally multi-stage distillation (F-3) and separated into fraction(s) (21) containing (V) and (II) and a second polyamine fraction (residue 20).