Process for the production of polyphenylene ethers having a desired polymerization degree

Claim 1

In a process for the production of polyphenylene ethers by oxidative polycondensation phenols, represented by a formula ##SPC6## wherein X represents a substituent selected from the class consisting of hydrogen, chlorine, bromine and iodine atoms, Q 1 represents a monovalent substituents selected from the class consisting of hydrogen, alkyl, haloalkyl having at least two carbon atoms between the halogen atom and the phenyl nucleus, alkoxy and haloalkoxy having at least two carbon atoms between the halogen atom and the phenyl nucleus, Q 2 , Q 3 and Q 4 are the same as Q 1 or halogen atom, provided that Q 1 , Q 2 , Q 3 and Q 4 are each free from a tertiary α-carbon atom, in the presence of a complex catalyst compound composed of a copper, manganese or cobalt salt as well as a primary, secondary or tertiary mono- or diamine as ligand, the method for producing polyphenylene ethers having any desired polymerization degree the improvement which comprises terminating the oxidative polycondensation-reaction by adding a reducing agent and simultaneously at least one member selected from the class consisting of dioxybenzenes and benzoquinones to the reaction medium at the stage of the desired polymerization degree, said dioxybenzenes being represented by the formula ##SPC7## and said benzoquinones being represented by the formula ##SPC8## or by the formula ##SPC9## wherein R and R' represents each a hydrogen atom or a substituent selected from the class consisting of alkyl and alkoxy having at most 4 carbon atoms.