Polyphenylene oxide prodn - by oxidative phenol coupling prepd from cobalt salt, 1,10-phenanthroline or dipyridyl

摘要

Oxidative coupling of phenols of formula (I) (where R is Me, Et, -CHMe2, Ph, Cl; R' is Me, Et, Ph, Cl; R" and R"' are H, Me, Et, Ph, Cl), pref. 2,6-dimethyl-, 2-Cl-6-Me- or 2,6-dichlorophenol, with O2 or O2-contg. gases in a solvent, takes place in presence of catalyst which consists of (a) a Co salt and (b) 1,10-phenanthroline or 2,2'-dipyridyl in 1.5 : 1 to 3 : 1 (1.75 : 1 to 2.25 : 1) N2 : Co molar ratio and an (in)organic base (II), in 1 : 1 to 5 : 1 (1.5 : 1 to 2.5 : 1) g. equiv. base: g. atom C ratio, under 1-20 (1-3) atmos. press. and at 0 - 150 (30 - 60) degrees C. - (II) may be an alkali(ne earth) metal base, esp. NaOH, or NaOR"" (where R"" is H, Me, Et or). Optimum Co salt concn. is 0.5 - 30 (5 - 15) mol. % w.r.T. (I). Polymers are colourless to light-coloured and are useful as heat-resistant films and coatings and injection moulded articles.