HIGH MOLECULAR WEIGHT POLY(2,6-DIMETHYL-1,4-PHENYLENE ETHER) AND PROCESS THEREFOR

• US 20090211967A1
• Filed: 10/22/2008
• Published: 08/27/2009
• Est. Priority Date: 02/21/2008
• Status: Active Grant

• Current Assignee: SHPP Global Technologies BV
• Original Assignee: Sabic Innovative Plastics IP BV (Government of Saudi Arabia)
• Inventors: Schoenmakers, Gert-Jan, Delsman, Erik Rene
• Granted Patent: US 8,025,158 B2
• Time in Patent Office: Days
• US Class Current: 210/500.230
• CPC Class Codes: C08G 65/4093 characterised by the process or apparatus used
• CPC Class Codes: C08G 65/44 by oxidation of phenols
• CPC Class Codes: C08G 65/485 Polyphenylene oxides
• CPC Class Codes: Y10T 428/2975 Tubular or cellular

Abstract

A poly(2,6-dimethyl-1,4-phenylene ether) having a high molecular weight and a reduced content of low molecular weight species can be prepared by a method that includes specific conditions for the oxidative polymerization, chelation, and isolation steps. The poly(2,6-dimethyl-1,4-phenylene ether) is particularly useful for the fabrication of fluid separation membranes.

Claims

1. A method of preparing a poly(2,6-dimethyl-1,4-phenylene ether), comprising:

oxidatively polymerizing 2,6-dimethylphenol in toluene solvent in the presence of a catalyst comprising copper ion and N,N′

-di-tert-butylethylenediamine to form a reaction mixture comprising a dissolved poly(2,6-dimethyl-1,4-phenylene ether), water, and the catalyst;

wherein the oxidative polymerizing comprises initiating oxidative polymerization in the presence of no more than 10 weight percent of the 2,6-dimethylphenol;

wherein at least 95 weight percent of the 2,6-dimethylphenol is added to the reaction mixture after the initiation of oxidative polymerization and over the course of at least 50 minutes;

wherein the oxidatively polymerizing comprises adding molecular oxygen and 2,6-dimethylphenol to the reaction mixture in a mole ratio of 0.3;

1 to 0.65;

1;

terminating the oxidative polymerization to form a post-termination reaction mixture;

combining a chelant comprising an alkali metal salt of nitrilotriacetic acid with the post-termination reaction mixture to form a chelation mixture comprising

an aqueous phase comprising chelated copper ion, and an organic phase comprising the dissolved poly(2,6-dimethyl-1,4-phenylene ether);

wherein the chelation mixture excludes dihydric phenols and aromatic amines;

maintaining the chelation mixture at a temperature of 40 to 55°

C. for 5 to 100 minutes;

separating the aqueous phase and the organic phase;

wherein the separation is conducted at a temperature of 40 to 55°

C.; and

isolating the poly(2,6-dimethyl-1,4-phenylene ether) from the separated organic phase;

wherein time elapsed between termination of the oxidative polymerization and isolating the poly(2,6-dimethyl-1,4-phenylene ether) is no more than 200 minutes; and

wherein the isolated poly(2,6-dimethyl-1,4-phenylene ether) has a number average molecular weight of at least 18,000 atomic mass units and less than 30 weight percent of molecules having a molecular weight less than 30,000 atomic mass units.

2. The method of claim 1, wherein the chelation mixture further excludes mild reducing agents selected from the group consisting of sulfur dioxide, sulfurous acid, sodium bisulfite, sodium thionite, tin (II) chloride, iron (II) sulfate, chromium (II) sulfate, titanium (III) chloride, hydroxylamines and salts thereof, phosphates, glucose, and mixtures thereof

3. The method of claim 1, wherein the oxidatively polymerizing 2,6-dimethylphenol comprises a first stage in which the reaction mixture is cooled to maintain a temperature of 10 to 35°

C.

4. The method of claim 3, wherein the oxidatively polymerizing 2,6-dimethylphenol comprises a second stage in which the reaction mixture is heated to maintain a temperature of 20 to 50°

C.

5. The method of claim 1, wherein the total weight of 2,6-dimethylphenol is 5 to 10 weight percent based on the total weight of 2,6-dimethylphenol and toluene solvent.

6. The method of claim 1, wherein the combining a chelant with the post-termination reaction mixture to form a chelation mixture comprises combining the post-termination reaction mixture with an aqueous solution of the chelant, adjusting the temperature of the resulting mixture to 40 to 55°

C., and combining the resulting temperature-adjusted mixture with water to form the chelation mixture.

7. The method of claim 1, excluding a solvent removal step between the terminating the oxidative polymerization and the isolating the poly(2,6-dimethyl-1,4-phenylene ether).

8. The method of claim 1, wherein the isolating the poly(2,6-dimethyl-1,4-phenylene ether) from the separated organic phase comprises mixing in a first stirred tank the separated organic phase and a first portion of antisolvent to produce a first poly(2,6-dimethyl-1,4-phenylene ether) slurry;

and mixing in a second stirred tank the first poly(2,6-dimethyl-1,4-phenylene ether) slurry and a second portion of antisolvent to produce a second poly(2,6-dimethyl-1,4-phenylene ether) slurry.

9. The method of claim 8, wherein the separated organic phase comprises 6 to 10 weight percent poly(2,6-dimethyl-1,4-phenylene ether).

10. The method of claim 8, wherein the first portion of antisolvent and the second portion of antisolvent each independently comprise 75 to 85 weight percent methanol and 15 to 25 weight percent toluene.

11. The method of claim 8, wherein the weight ratio of the separated organic phase to the first portion of antisolvent is 1.5:

1 to 2;

1; and

wherein the weight ratio of the first poly(2,6-dimethyl-1,4-phenylene ether) slurry to the second portion of antisolvent is 0.9;

1 to 1.2;

1.

12. The method of claim 8, wherein the mixing in a first stirred tank and the mixing in a second stirred tank are each independently conducted at a temperature of 45 to 55°

C.

13. The method of claim 8, wherein the mixing in a first stirred tank and the mixing in a second stirred tank are characterized by a total mixing energy of less than or equal to 4 kilojoules per kilogram.

14. The method of claim 1, wherein the isolated poly(2,6-dimethyl-1,4-phenylene ether) has a weight average molecular weight of at least 150,000 atomic mass units.

15. The method of claim 1, wherein the isolated poly(2,6-dimethyl-1,4-phenylene ether) has a weight average molecular weight of 150,000 to 230,000 atomic mass units.

16. The method of claim 1, wherein a difference in intrinsic viscosity less than or equal to 25 percent is observed between the dissolved poly(2,6-dimethyl-1,4-phenylene ether) and the isolated poly(2,6-dimethyl-1,4-phenylene ether).

17. The method of claim 1, wherein a difference in intrinsic viscosity of 10 to 25 percent is observed between the dissolved poly(2,6-dimethyl-1,4-phenylene ether) and the isolated poly(2,6-dimethyl-1,4-phenylene ether).

18. The method of claim 1, wherein a difference in intrinsic viscosity less than or equal to 0.30 deciliters per gram is observed between the dissolved poly(2,6-dimethyl-1,4-phenylene ether) and the isolated poly(2,6-dimethyl-1,4-phenylene ether).

19. The method of claim 1, wherein a difference in weight percent of molecules having a molecular weight less than 30,000 atomic mass units of less than or equal to 25 weight percent is observed between the dissolved poly(2,6-dimethyl-1,4-phenylene ether) and the isolated poly(2,6-dimethyl-1,4-phenylene ether).

20. The method of claim 1, wherein a difference in weight percent of molecules having a molecular weight less than 30,000 atomic mass units of 10 to 25 weight percent is observed between the dissolved poly(2,6-dimethyl-1,4-phenylene ether) and the isolated poly(2,6-dimethyl-1,4-phenylene ether).

21. The method of claim 1, wherein the isolated poly(2,6-dimethyl-1,4-phenylene ether) has a copper concentration less than or equal to 5 parts per million by weight.

22. The method of claim 1, wherein the isolated poly(2,6-dimethyl-1,4-phenylene ether) has a copper concentration of 0.5 to 5 parts per million by weight.

23. The method of claim 1, wherein the catalyst further comprises dimethyl-n-butylamine, di-n-butylamine, or a mixture thereof.

24. The method of claim 1, wherein the catalyst further comprises dimethyl-n-butylamine and di-n-butylamine.

25. The method of claim 1,

wherein the catalyst further comprises dimethyl-n-butylamine and di-n-butylamine;

wherein the oxidative polymerizing comprises initiating oxidative polymerization in the presence of 1 to 3 weight percent of the 2,6-dimethylphenol;

wherein at least 97 weight percent of the 2,6-dimethylphenol is added to the reaction mixture after the initiation of oxidative polymerization and over the course of 55 to 65 minutes;

wherein the oxidatively polymerizing comprises adding molecular oxygen and 2,6-dimethylphenol to the reaction mixture in a mole ratio of 0.3;

1 to 0.5;

1;

wherein the oxidatively polymerizing 2,6-dimethylphenol comprises a first stage in which the reaction mixture is cooled to maintain a temperature of 20 to 30°

C., and a second stage in which the reaction mixture is heated to maintain a temperature of 30 to 40°

C.;

wherein the method excludes a solvent removal step between the terminating the oxidative polymerization and the isolating the poly(2,6-dimethyl-1,4-phenylene ether);

wherein the chelation mixture is maintained at a temperature of 45 to 55°

C. for 40 to 70 minutes;

wherein the separating the aqueous phase and the organic phase is conducted at a temperature of 45 to 55°

C.;

wherein time elapsed between termination of the oxidative polymerization and isolating the poly(2,6-dimethyl-1,4-phenylene ether) is 30 to 60 minutes;

wherein the isolated poly(2,6-dimethyl-1,4-phenylene ether) has a number average molecular weight of 20,000 to 35,000 atomic mass units and 16 to 20 weight percent of molecules having a molecular weight less than 30,000 atomic mass units; and

wherein the isolated poly(2,6-dimethyl-1,4-phenylene ether) has a copper concentration of 0.5 to 5 parts per million by weight.

26. A poly(2,6-dimethyl-1,4-phenylene ether) made by the method of claim 25.

27. A fiber comprising the poly(2,6-dimethyl-1,4-phenylene ether) solid of claim 26.

28. An article comprising the poly(2,6-dimethyl-1,4-phenylene ether) solid of claim 26.

29. A poly(2,6-dimethyl-1,4-phenylene ether) solid having a number average molecular weight of at least 18,000 atomic mass units, and less than 30 weight percent of molecules having a molecular weight less than 30,000 atomic mass units.

30. The poly(2,6-dimethyl-1,4-phenylene ether) solid of claim 29, having a copper concentration less than or equal to 5 parts per million by weight.

31. The poly(2,6-dimethyl-1,4-phenylene ether) solid of claim 30, having

a number average molecular weight of 20,000 to 35,000 atomic mass units,

to 20 weight percent of molecules having a molecular weight less than 30,000 atomic mass units, and

a copper concentration of 0.5 to 5 parts per million by weight.

32. A fiber comprising the poly(2,6-dimethyl-1,4-phenylene ether) solid of claim 29.

33. An article comprising the poly(2,6-dimethyl-1,4-phenylene ether) solid of claim 29.

34. The article of claim 33, wherein the article is an asymmetric hollow fiber membrane.

35. A fluid separation apparatus comprising the asymmetric hollow fiber membrane of claim 34.