Method of preparing a poly (phenylene ether), poly(phenylene ether) made thereby, and article comprising the poly(phenylene ether)

1. A method for preparing a poly(phenylene ether), the method comprising:

feeding an oxygen-containing gas phase to a single continuous flow reactor that contains a reaction mixture comprising a phenol, a transition metal catalyst, and an organic solvent; and oxidatively polymerizing the reaction mixture at a temperature of 20 to 50° C., to form a poly(phenylene ether);

wherein the reaction mixture has a residence time of less than or equal to 30 minutes in the single continuous flow reactor; and

wherein the reaction mixture comprises less than 500 ppm of dissolved transition metal catalyst, based on the total weight of the reaction mixture;

wherein the continuous flow reactor is a millireactor or a microreactor characterized by a volumetric mass transfer coefficient of 0.1 to 5 sec −1 .

2. The method of claim 1 , wherein the continuous flow reactor is characterized by a heat transfer per unit volume of greater than 500 m −1 .

3. The method of claim 1 , wherein the phenol comprises 2,6-dimethylphenol.

4. The method of claim 1 , wherein the transition metal catalyst is a copper-amine catalyst.

5. The method of claim 1 , wherein the organic solvent comprises toluene, benzene, chlorobenzene, ortho-dichlorobenzene, nitrobenzene, trichloroethylene, ethylene dichloride, dichloromethane, chloroform, or a combination thereof.

6. The method of claim 1 , wherein the reaction mixture further comprises a dihydric phenol.

7. The method of claim 1 , wherein the reaction mixture further comprises one or more of

a secondary monoamine, a tertiary monoamine, or a combination thereof;

a bromide ion source; and

a phase transfer agent.

8. The method of claim 1 , wherein

feeding the oxygen-containing gas phase is at a flow rate effective to provide an oxygen:phenol molar ratio of 1:1 to 1:1.2; and

the reaction mixture has a residence time of less than or equal to 15 minutes.

9. The method of claim 1 , further comprising isolating the poly(phenylene ether) from the reaction mixture.

10. The method of claim 1 , wherein the poly(phenylene ether) has an intrinsic viscosity of greater than or equal to 0.04 to 2 deciliter per gram, a polydispersity index of 1.5 to 2.9.

11. The method of claim 1 , wherein the poly(phenylene ether) has an amine content of less than 1 weight percent.

12. The method of claim 1 , further comprising introducing at least a portion of the reaction mixture into an infrared spectroscopy system to produce first signal for quantifying the amount of phenol, the molecular weight of the poly(phenylene ether), or both, and comparing the first signal to a calibration curve generated from a plurality of signals from standards of known phenol concentration, poly(phenylene ether) molecular weight, or both, to determine the amount of phenol in the reaction mixture, the molecular weight of the poly(phenylene ether), or both.

13. A poly(phenylene ether) made by the method of claim 1 .

14. An article comprising the poly(phenylene ether) of claim 13 .

15. A method for the analysis of a poly(phenylene ether) reaction mixture, the method comprising:

introducing a sample of a reaction mixture comprising a phenol and a poly(phenylene ether) into an infrared spectroscopy system to produce first signal for quantifying the amount of phenol, the molecular weight of the poly(phenylene ether), or both, and

comparing the first signal to a calibration curve generated from a plurality of signals from standards of known phenol concentration, poly(phenylene ether) molecular weight, or both, to determine the amount of phenol in the reaction mixture, the molecular weight of the poly(phenylene ether), or both.

16. The method of claim 15 , wherein the reaction mixture obtained from a method for preparing a poly(phenylene ether) according to the method of claim 1 .