Method of forming phenylene ether oligomer

1. A method of forming a phenylene ether oligomer, the method comprising:

reacting 2,6-dimethylphenol in the presence of toluene, oxygen, copper ion, bromide ion, and an alkylenediamine to form a first reaction mixture comprising 40 to 90 weight percent residual 2,6-dimethylphenol, and 10 to 60 weight percent 3,3′,5,5′-tetramethyl-4,4′-dihydroxybiphenyl, 3,3′,5,5′-tetramethyldiphenoquinone, or a combination thereof; wherein weight percent values are based on the weight of initial 2,6-dimethylphenol; and wherein the reaction of the 2,6-dimethylphenol is conducted

at a mole ratio of 2,6-dimethylphenol to copper ion of 300:1 to 1000:1,

at a mole ratio of alkylenediamine to copper ion of 2:1 to 8:1,

in the presence of 0 to 0.2 weight percent of tertiary monoamine, based on the weight of toluene, and

at a temperature of 50 to 110° C.;

reacting the residual 2,6-dimethylphenol in the presence of toluene, oxygen, copper ion, bromide ion, and alkylenediamine to form a second reaction mixture comprising 40 to 90 weight percent poly(2,6-dimethyl-1,4-phenylene ether); wherein the reacting residual 2,6-dimethylphenol is conducted at a temperature of 25 to 60° C.; and wherein any 3,3′,5,5′-tetramethyl-4,4′-dihydroxybiphenyl present in the first reaction mixture is substantially converted to 3,3′,5,5′-tetramethyldiphenoquinone in the second reaction mixture;

chelating the copper ion; and

reacting the poly(2,6-dimethyl-1,4-phenylene ether) and the 3,3′,5,5′-tetramethyldiphenoquinone to form a phenylene ether oligomer having the structure

wherein x and y are independently 0 to 20, provided that the sum of x and y is at least 1 and no greater than 30; wherein the reacting the poly(2,6-dimethyl-1,4-phenylene ether) and the 3,3′,5,5′-tetramethyldiphenoquinone is conducted at a temperature of 50 to 100° C.

2. The method of claim 1 , wherein the alkylenediamine is selected from the group consisting of N,N′-di-(C 1-12 -alkyl)ethylenediamines, N,N,N′-tri-(C 1-12 -alkyl)ethylenediamines, N,N,N′N′-tetra-(C 1-12 -alkyl)ethylenediamines, N,N′-di-(C 1-12 -alkyl)-1,2-propylenediamines, N,N,N′-tri-(C 1-12 -alkyl)-1,2-propylenediamines, N,N,N′N′-tetra-(C 1-12 -alkyl)-1,2-propylenediamines, N,N′-di-(C 1-12 -alkyl)-1,3-propylenediamines, N,N,N′-tri-(C 1-12 -alkyl)-1,3-propylenediamines, N,N,N′N′-tetra-(C 1-12 -alkyl)-1,3-propylenediamines, and combinations thereof.

3. The method of claim 1 , wherein the alkylenediamine is selected from the group consisting of N,N′-di-tert-butylethylenediamine, N,N,N′,N′-tetraethylethylenediamine, N,N,N′,N′-tetramethylethylenediamine, N,N ′-diethyl-N,N ′-dimethylethylenediamine, N,N′-diethylethylenediamine, N,N′-dimethylethylenediamine, N,N,N′,N′-tetramethyl-1,3-butylenediamine, and combinations thereof.

4. The method of claim 1 , wherein the reaction of the 2,6-dimethylphenol is conducted at a mole ratio of 2,6-dimethylphenol to copper ion of 400:1 to 900:1.

5. The method of claim 1 , wherein the reaction of the 2,6-dimethylphenol is conducted in the presence of 0 to 0.1 weight percent tertiary monoamine, based on the weight of toluene.

6. The method of claim 1 , wherein the reaction of the 2,6-dimethylphenol is conducted at a mole ratio of alkylenediamine to copper ion of 3:1 to 6:1.

7. The method of claim 1 , wherein the reaction of the 2,6-dimethylphenol is conducted at a temperature of 55 to 100° C.

8. The method of claim 1 , wherein the reaction of the 2,6-dimethylphenol is conducted in the presence of 0 to 1 weight percent secondary monoamine, based on the weight of 2,6-dimethylphenol.

9. The method of claim 1 , wherein the first reaction mixture comprises 40 to 80 weight percent residual 2,6-dimethylphenol, and 20 to 60weight percent 3,3′,5,5′-tetramethyl-4,4′-dihydroxybiphenyl, 3,3′,5,5′-tetramethyldiphenoquinone, or a combination thereof, wherein weight percent values are based on the weight of initial 2,6-dimethylphenol.

10. The method of claim 1 , wherein the reacting residual 2,6-dimethylphenol is conducted at a temperature of 30 to 45° C.

11. The method of claim 1 , wherein the reacting the poly(2,6-dimethyl-1,4-phenylene ether) and the 3,3′,5,5′-tetramethyldiphenoquinone is conducted at a temperature of 70 to 90° C.

12. The method of claim 1 , wherein the reacting the 2,6-dimethylphenol and the reacting the residual 2,6-dimethylphenol are conducted in the absence of any solvent other than toluene.

13. The method of claim 1 , wherein the reacting the poly(2,6-dimethyl-1,4-phenylene ether) and the 3,3′,5,5′-tetramethyldiphenoquinone is conducted in the presence of the chelated copper ion.

14. The method of claim 1 , wherein the sum of x and y is less than or equal to 20.

15. The method of claim 1 ,

wherein the alkylenediamine comprises N,N′-di-tent-butylethylenediamine;

wherein the reaction of the 2,6-dimethylphenol is conducted

at a mole ratio of 2,6-dimethylphenol to copper ion of 400:1 to 800:1,

at a mole ratio of N,N′-di-tert-butylethylenediamine to copper ion of 3:1 to 5:1,

in the presence of 0 to 0.1 weight percent secondary monoamine, based on the weight of 2,6-dimethylphenol, and

at a temperature of 70 to 90° C.;

wherein the first reaction mixture comprises 40 to 80 weight percent residual 2,6-dimethylphenol, and 20 to 60 weight percent 3,3′,5,5′-tetramethyl-4,4′-dihydroxybiphenyl, 3,3′,5,5′-tetramethyldiphenoquinone, or a combination thereof, based on the weight of initial 2,6-dimethylphenol;

wherein the reacting residual 2,6-dimethylphenol is conducted at a temperature of 30 to 45° C.;

wherein the reacting the poly(2,6-dimethyl-1,4-phenylene ether) and the 3,3′,5,5′-tetramethyldiphenoquinone is conducted at a temperature of 70 to 90° C.; and

wherein the sum of x and y is less than or equal to 20.