Patent ID: 8215495

Claim:
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.