Process for the preparation of polyphenylene oxides with hydrolytically stable copper catalysts

Claim 1

A process for formation of a polyphenylene oxide having the formula ##STR5## where R and R' are lower primary alkyl and n is a number representing the average degree of polymerization and is at least 100 which comprises: oxidatively coupling the corresponding monohydric phenol with an oxygen-containing gas under polymer-forming reaction conditions in a liquid reaction mixture which is essentially free of ammonium ion and in which the phenol is soluble in the presence of a copper-amine complex soluble in the reaction mixture comprising a. copper ion b. bromide ion c. a diamine having the formula R.sub.b HN--R.sub.a --NHR.sub.c where R a is C 2-4 -alkylene or C 3-7 -cycloalkylene and R b and R c are isopropyl or C 4-8 -tertiary alkyl, including cycloalkyl, in which only the α-carbon atom has no hydrogens, there being at least two and no more than three carbon atoms separating the two nitrogen atoms d. a tertiary amine which is N-methylpyrrolidine, triethylenediamine or a trialkylamine wherein at least two of the alkyl groups are methyl and the third is C 1-8 primary or C 3-8 secondary alkyl, wherein, the molar ratio of (b) to (a) is at least 2, the molar ratio of (c) to (a) is at least 1 and the ratio of equivalents of (d) to moles of (a) is at least 6.