Patent ID: 8357769

Claim:
A method for producing a polyphenylene ether, comprising: preparing a polymerization solution comprising 100 parts by mass in total of 10 to 25 parts by mass of a phenolic compound (M) and 75 to 90 parts by mass of an aromatic solvent (A), and 0.1 to 10 parts by mass of a catalyst (C) comprising a metal salt as a component; passing an oxygen-containing gas through the polymerization solution to oxidatively polymerize the phenolic compound (M); mixing a chelating agent aqueous solution with the polymerization solution to terminate the polymerization; subjecting a diphenoquinone compound produced as a by-product to disposal by a quinone-coupling or to a reduction removal; and thereafter, subjecting the polymerization solution to a liquid-liquid separation to separate a water phase to obtain the polyphenylene ether, wherein 0.001 to 0.004 part by weight of an ion catalyst (D) is added to the polymerization solution before the liquid-liquid separation is carried out.