High molecular weight poly(2,6-dimethyl-1,4-phenylene ether) and process therefor
First Claim
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1. A poly(2,6-dimethyl-1,4-phenylene ether) made by a method comprisingoxidatively polymerizing 2,6-dimethylphenol in toluene solvent in the presence of a catalyst comprising copper ion, N,N′
- -di-tert-butylethylenediamine, dimethyl-n-butylamine, and di-n-butylamine 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 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.;
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 comprisingan aqueous phase comprising chelated copper ion, andan 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 45 to 55°
C. for 40 to 70 minutes;
separating the aqueous phase and the organic phase;
wherein the separation is conducted at a temperature of 45 to 55°
C.;
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 30 to 60 minutes;
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 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.
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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.
22 Citations
3 Claims
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1. A poly(2,6-dimethyl-1,4-phenylene ether) made by a method comprising
oxidatively polymerizing 2,6-dimethylphenol in toluene solvent in the presence of a catalyst comprising copper ion, N,N′ - -di-tert-butylethylenediamine, dimethyl-n-butylamine, and di-n-butylamine 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 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.;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 45 to 55°
C. for 40 to 70 minutes;separating the aqueous phase and the organic phase;
wherein the separation is conducted at a temperature of 45 to 55°
C.;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 30 to 60 minutes; 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 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. - View Dependent Claims (2, 3)
- -di-tert-butylethylenediamine, dimethyl-n-butylamine, and di-n-butylamine to form a reaction mixture comprising a dissolved poly(2,6-dimethyl-1,4-phenylene ether), water, and the catalyst;
Specification