Method for isolation of a dianhydride and dianhydrides prepared by the method

Patent metadata

Field	Value
Publication number	US-10407397-B2
Application number	US-201716096080-A
Country	US
Kind code	B2
Filing date	Apr 19, 2017
Priority date	Apr 27, 2016
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent for a first time period, at a first extraction temperature and subsequent to the first time period, extracting the aqueous reaction mixture with an organic solvent for a second time period, at a second extraction temperature. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

First claim

What is claimed is:

1. A method for producing an aromatic dianhydride, the method comprising
reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst under conditions effective to provide an aqueous reaction mixture comprising an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt, wherein the reacting is at a reaction temperature that is 140 to 250° C. and a reaction pressure of 150 to 300 psig;
removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent for a first time period, at a first extraction temperature that is 60 to 160° C., provided that the first extraction temperature is at least 10° C. lower than a maximum of the reaction temperature;
subsequent to the first time period, extracting the aqueous reaction mixture with an organic solvent for a second time period, at a second extraction temperature that is 140 to 250° C., provided that the second extraction temperature is at least 5° C. higher than the first extraction temperature; and
converting the aromatic tetraacid salt to the corresponding aromatic dianhydride.

2. The method of claim 1 , wherein the substituted or unsubstituted phthalic anhydride is phthalic anhydride, 3-halophthalic anhydride, 4-halophthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, or a combination of the foregoing.

3. The method of claim 1 , wherein the exchange catalyst is a (C 1-20 alkyl)-substituted amine.

4. The method of claim 1 , wherein the initial molar ratio of phthalic anhydride to aromatic diimide is 4:1 to 5.5:1.

5. The method of claim 1 , wherein the initial molar ratio of amine exchange catalyst to the phthalic anhydride is 1:1 to 2:1.

6. The method of claim 1 , wherein the aqueous reaction mixture further comprises at least one of the aromatic diimide and the substituted or unsubstituted phthalic anhydride.

7. The method of claim 1 wherein
the aromatic diimide is 4,4′-bisphenol A-bis-N-methylphthalimide, 3,4′-bisphenol A-bis-N-methylphthalimide, 3,3′-bisphenol A-bis-N-methylphthalimide, or a combination of the foregoing; and
the aromatic dianhydride is 4,4′-bisphenol A-bis-dianhydride, 3,4′-bisphenol A-bis-dianhydride, 3,3′-bisphenol A-bis-dianhydride, or a combination of the foregoing.

8. The method of claim 1 , wherein the organic solvent is toluene, xylene, chlorobenzene, ortho-dichlorobenzene, or a combination of the foregoing.

9. The method of claim 1 , wherein the volumetric ratio of the aqueous medium to the organic solvent is 0.3:1 to 3:1.

10. The method of claim 1 , wherein the extracting provides
an extracted aqueous stream comprising the aromatic tetraacid salt and optionally the aromatic triacid salt, the aromatic imide-diacid salt, a substituted or unsubstituted phthalic acid salt, or a combination comprising at least one of the foregoing; and
an organic stream comprising the organic solvent, N-substituted phthalimide, and optionally unreacted aromatic diimide.

11. The method of claim 1 , wherein at least 50% of the phthalimide in the aqueous reaction mixture at the beginning of the first time period is extracted into the organic solvent at the end of the first time period.

12. The method of claim 1 , wherein conversion of the aromatic diimide to the aromatic dianhydride is greater than 70% at the end of the second time period.

13. The method of claim 1 wherein the method further comprises repeating the extracting to provide conversion of the aromatic diimide to the aromatic dianhydride at the end of the second time period of greater than 70%.

14. The method of claim 1 , wherein the method is a batchwise method.

15. The method of claim 1 , wherein the method is a continuous method.

16. The method of claim 1 , wherein the extracting for the first time period and the second time period are in the same extractor.

17. The method of claim 1 , wherein the extracting for the first time period and the second time period are in different extractors.

18. The method of claim 1 , wherein
the reaction temperature is 160 to 200° C.;
the first extraction temperature is 60 to 150° C.; and
the second extraction temperature is 160 to 200° C.

19. The method of claim 1 , wherein
the reaction temperature is 160 to 200° C.;
the first extraction temperature is 60 to 150° C.;
the second extraction temperature is 160 to 200° C.;
the aromatic diimide is of the formula

the aromatic tetra acid salt is of the formula

the aromatic triacid salt is of the formula

the aromatic imide-diacid salt is of the formula

the aromatic dianhydride is of the formula

 and
an aromatic imide-anhydride is of the formula

wherein in the foregoing formulas
Z is an aromatic C 6-24 monocyclic or polycyclic moiety optionally substituted with 1 to 6 C 1-8 alkyl groups, 1 to 8 halogen atoms, or a combination comprising at least one of the foregoing;
R 1 is a monovalent C 1-4 organic group; and
Y is a tri(C 1-20 alkyl)ammonium group or a proton.

20. The method of claim 1 , wherein the aromatic dianhydride has an imide anhydride content of less than or equal to 3 wt %, based on the total weight of the aromatic dianhydride.

Assignees

• Sabic Global Technologies Bv

Inventors

• Royer Aaron
• Werling Robert J
• Jimenez Jorge
• Johnson Norman Enoch

Classifications

• C07D307/89 Primary

  with two oxygen atoms directly attached in positions 1 and 3 · CPC title