Extraction process for removal of impurities from mother liquor in the synthesis of carboxylic acid
View Patent ↗A method for removing impurities from a mother liquor comprising a carboxylic acid, a metal catalyst, impurities by (a) evaporating the mother liquor comprising a carboxylic acid, the metal catalyst, impurities, water and a solvent in a first evaporator zone to produce a vapor stream and a concentrated mother liquor stream; (b) evaporating the concentrated mother liquor stream in a second evaporator zone to form a solvent rich stream and a super concentrated mother liquor stream; (c) separating organic impurities with a water-solvent solution from the super concentrated mother liquor in a solid-liquid separation zone to form an aqueous stream and a second aqueous stream; (d) mixing in a mixing zone water and optionally and extraction solvent with the aqueous stream and second aqueous stream to form an aqueous mixture; and (e) adding an extraction solvent to the aqueous mixture in an extraction zone to form an extract stream and a raffinate stream.
1. A process comprising the following steps:
(a) evaporating a mother liquor comprising a carboxylic acid, a metal catalyst, impurities, water and a solvent in a first evaporator zone to produce a vapor stream and a concentrated mother liquor stream;
(b) evaporating said concentrated mother liquor stream in a second evaporator zone to form a solvent rich stream and a super concentrated mother liquor stream;
(c) separating organic impurities with a water-solvent solution from said super concentrated mother liquor stream in a solid-liquid separation zone to form an aqueous stream and a second aqueous stream;
(d) mixing in a mixing zone water and optionally an extraction solvent with said aqueous stream and said second aqueous stream to form an aqueous mixture;
(e) adding an extraction solvent to said aqueous mixture in an extraction zone to form an extract stream and a raffinate stream; and
(f) optionally separating said extract stream in a separation zone to form a high boiling point organic impurities stream and a recovered extraction solvent stream.
2. The process according to claim 1 wherein about 50 wt % to about 80 wt % of said solvent and water is removed from said mother liquor in step (a).
3. The process according to claim 2 wherein about 75 wt % to about 99 wt % of said solvent and water is removed from said mother liquor in step (a) and step (b) combined.
4. The process according to claim 1 wherein about 85 wt % to about 99 wt % of said solvent and water is removed from said mother liquor in step (a) and step (b) combined.
5. The process according to claim 1 wherein about 90 wt % to about 99 wt % of said solvent and water is removed from said mother liquor in step (a) and step (b) combined.
6. The process according to claim 1 wherein said water-solvent solution is added to said solid liquid separation zone at a temperature range of about 20° C. to about 70° C.
7. The process according to claim 1 wherein said water-solvent solution is added to said solid liquid separation zone at a temperature range of about 30° C. to about 50° C.
8. The process according to claim 1 wherein said extraction zone comprises a counter current extractor.
9. The process according to claim 1 wherein said extraction zone comprises a single stage extractor.
10. The process according to claim 1 wherein said solvent rich stream comprises a solvent selected from the group consisting of n-propyl acetate, isopropyl acetate, isobutyl acetate, sec-butyl acetate, ethyl acetate and n-butyl acetate.
11. The process according to claim 1 wherein said second evaporator zone comprises an evaporator operated at a temperature of about 20° C. to about 70° C.
12. A process comprising the following steps:
(a) evaporating a mother liquor comprising a carboxylic acid, a metal catalyst, impurities, water and a solvent in a first evaporator zone to produce a vapor stream and a concentrated mother liquor stream;
(b) evaporating said concentrated mother liquor stream in a second evaporator zone to form a solvent rich stream and a super concentrated mother liquor stream; wherein about 85 wt % to about 99 wt % of said solvent and water is removed from said mother liquor in step (a) and step (b) combined;
(c) separating organic impurities with a water-solvent solution from said super concentrated mother liquor stream in a solid-liquid separation zone to form an aqueous stream and a second aqueous stream; wherein said water-solvent solution is added to said solid liquid separation zone at a temperature range of about 20° C. to about 70° C.;
(d) mixing in a mixing zone water and optionally an extraction solvent with said aqueous stream and said second aqueous stream to form an aqueous mixture;
(e) adding an extraction solvent to said aqueous mixture in an extraction zone to form an extract stream and a raffinate stream; and
(f) optionally separating said extract stream in a separation zone to form a high boiling point organic impurities stream and a recovered extraction solvent stream.
13. The process according to claim 12 wherein about 50 wt % to about 80 wt % of said solvent and water is removed from said mother liquor in step (a).
14. The process according to claim 12 wherein said extraction zone comprises a counter current extractor.
15. The process according to claim 12 wherein said extraction zone comprises a single stage extractor.
16. The process according to claim 12 wherein said solvent rich stream comprises a solvent selected from the group consisting of n-propyl acetate, isopropyl acetate, isobutyl acetate, sec-butyl acetate, ethyl acetate and n-butyl acetate.