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US 5,684,180 AGranted
Fractionation and purification of aromatic polyamine mixtures and the use thereof
AssigneeBayer Aktiengesellschaft
InventorsHartmut Knofel, Michael Brockelt
Life of this patent
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Abstract
The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and to the use thereof.
Claims9
A process for the fractionation and purification of aromatic polyamine mixtures comprising:
- a) mixing the polyamine starting mixture in a first extraction stage with a two-phase system comprising
- (i) a hydrophobic solvent phase which consists essentially of hydrophobic solvent and optionally an aromatic auxiliary amine which is substantially insoluble in water and exhibits at normal pressure a boiling point which is at least 20.degree. C. below the boiling point of the lowest-boiling component of the starting mixture and at least 20.degree. C. above the boiling point of the solvent, and optionally polyamine, and
- (ii) an aqueous phase consisting essentially of water, a strong acid and auxiliary amine present at least in part in the salt form, and optionally polyamines present at least in part in the salt form,
- with said first extraction stage operating on the countercurrent principle, and wherein said polyamine starting mixture is introduced into said first extraction stage with said hydrophobic solvent phase, with a first aqueous phase and a first organic phase exiting said first extraction stage,
- b) distilling said first organic phase in a multi-stage distillation into
- i) a first fraction consisting essentially of hydrophobic solvent and optionally auxiliary amine,
- ii) a second fraction consisting essentially of auxiliary amine and optionally hydrophobic solvent, and
- iii) a distillation residue consisting essentially of a first polyamine fraction,
- c) extracting said first aqueous phase in a second extraction stage with a solvent phase consisting essentially of hydrophobic solvent and auxiliary amine, said second extraction stage operating on the countercurrent principle, with i) a second aqueous phase, said second aqueous phase being reduced in amine content and ii) a second organic phase exiting said second extraction stage,
- d) separating at least a portion of said second organic phase in a distillation stage into
- i) a first distillate consisting essentially of hydrophobic solvent and auxiliary amine, and
- ii) a distillation residue consisting essentially of a second polyamine fraction,
- e) recycling said second aqueous phase as at least a portion of said aqueous phase and
- h) combining said first distillate with at least a portion of said second fraction to form said solvent phase.
11 more elements
A process for the fractionation and purification of aromatic polyamine mixtures characterized in that
- a) the polyamine starting mixture (A) is distributed in a two-phase system comprising (i) a hydrophobic solvent phase (B) which is composed substantially of hydrophobic solvent and optionally an aromatic auxiliary amine that is virtually insoluble in water and under normal pressure has a boiling point at least 20.degree. C. below the boiling point of the lowest boiling component of the starting mixture and at least 20.degree. C. above the boiling point of the solvent, and optionally of polyamine, and (ii) an aqueous phase (C) comprising substantially water, a strong acid and auxiliary amine present at least partially in the salt form, and optionally polyamines present at least partially in the salt form, with the assistance of an extraction stage (3) operating on the countercurrent principle with mixing of the phases, by introducing the starting polyamine mixture via the organic phase (B), into extraction stage (3), and at least partially separating the organic phase (D) leaving extraction stage (3), optionally after passing through a wash stage (6.0), in a multistage distillation (6.1), (6.2) into a first fraction (E) reused in extraction stage (3) and substantially composed of hydrophobic solvent and optionally auxiliary amine, a second fraction (F), substantially composed of auxiliary amine and optionally hydrophobic solvent and a distillation residue (G), substantially composed of a first polyamine fraction and the aqueous phase (H) leaving the extraction stage is passed,
- b) optionally at least partially via an intermediate extraction stage (4),
- c) into an extraction stage (5), in which the aqueous phase is extracted according to the countercurrent principle with a solvent phase (J) composed of solvent and auxiliary amine, and the aqueous phase (K) depleted in polyarylamine results, which is passed
- d) optionally at least partially via an intermediate distillation stage (8) and then combined with the optionally remaining remainder of (K) and is reused
- e) as stream (C), in which the stated aqueous phase,
- f) optionally at least partially via an upstream extraction stage (2)
- g) is introduced into extraction stage (3), optionally after the addition of auxiliary amine and/or water, and
- h) the organic phase (L) obtained in extraction stage (5) is at least partially split by distillation (7.1) into a distillate (M) comprising auxiliary amine and solvent and a distillation residue (N) composed of a second polyamine fraction, whereupon the distillate (M) is combined with at least a proportion of the distillate (F) obtained in distillation stage (6.2) and is then returned to extraction stage (5) and there used again.
5 more elements
Dependencies are inferred from the claim text.