2,6-dimethyphenol composition
A 2,6-dimethylphenol composition having an m-cresol content of from 15 to 700 ppm on a weight basis has effects of drastically improving polymerization activity and particularly, improving the color tone of polyphenylene ethers. Therefore, the composition makes it possible to provide a preparation process having improved productivity, and at the same time, provide polyphenylene ethers having good quality.
1. A process for preparing a polyphenylene ether, which comprises subjecting a 2,6-dimethylphenol composition having an m-cresol content of from 15 ppm to 700 ppm based on the weight of 2,6-dimethylphenol to oxidative polymerization using a catalyst and an oxygen-containing gas, wherein the catalyst comprises, as constituents thereof, a copper compound, a halogen compound and a diamine compound represented by the following formula (1):
wherein R 1 , R 2 , R 3 and R 4 each independently represents a hydrogen atom, a linear or branched C 1-6 alkyl group, with the proviso that they do not represent a hydrogen atom at the same time; and R 5 represents a linear or methyl-branched C 2-5 alkylene group.
2. The process for preparing a polyphenylene ether according to claim 1 , wherein the catalyst further comprises, as a constituent thereof, at least one of a tertiary monoamine compound and a secondary monoamine compound.
3. A polyphenylene ether obtained by the process as claimed in claim 1 .
4. The polyphenylene ether of claim 3 , which has an intrinsic viscosity [η], as measured at 30° C. in a chloroform solution, of 0.49 dl/g or less.
5. The process of claim 1 , wherein the m-cresol content is from 15 ppm to 300 ppm.
6. The process of claim 1 , wherein the m-cresol content is from 15 ppm to 200 ppm.
7. The process of claim 1 , wherein the m-cresol content is from 15 ppm to 100 ppm.
8. The process of claim 1 , wherein the oxidative polymerization is solution polymerization.