The oxidation of 2, 6‐xylenol by oxygen, catalysed by a copper complex, leads to poly‐phenylene ether or quinones according to the amount of added pyridine. The first oxidation step is common in the two processes giving aryloxy radicals. The pH of the medium plays a fundamental role so that at low values a second electron is removed and the diradical rearranges into a cation in acidic medium. This cation may add to the monomer or to H2O thus explaining the production of several quinones. It has been shown that in methanol solvent, a nucleophilic reagent, addition to the cation takes place giving a new product which was characterised by thin layer chromatography (tlc).

Die aus den Amidoximen (I) mit Hydroxylamin zugänglichen N‐Hydroxyamidoxime (II) kondensieren mit den Aldehyden (III) zu den N‐Hydroxyoxadiazolinen (IV).

A structure of the solid catalyst used for oxidative coupling of phenols is proposed from an NMR study in various solvents. The stoichiometry of the solid prepared via oxidation of Cu2Clz by 0 2 in a pyridine/methanol mixture is discussed in view of the coordination of the ligands. The catalytic activity could be due to the /O\ -cu-cugroup and the exchangeability of the pyridine ligands. ZUSAMMENFASSUNG:Aus NMR-spektroskopischen Untersuchungen in verschiedenen Losungsmitteln wird eine Struktur des Katalysators fur die oxidative Kupplung von Phenolen vorgestellt. Die Stochiometrie des durch 02-Oxidation von CuzCl2 in einem Pyridin/Methanol-Gemisch dargesteuten Festkorpers und die Ligandenkoordination werden diskutiert. Die Ursache der katalytischen Aktivitiit scheint in der Gegenwart der Gruppe /O\ -cu-cuund in der Austauschfahigkeit der Liganden am Pyridin zu bestehen.

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