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The kinetics of thermal dissociation of urethane, oxazolidone, and isocyanurate groups were measured on model compounds [5-(phenoxymethyl)-3-phenyl-2-oxazolidinone (I), 5-(phenoxymethyl)-3cyclohexyl-2-oxazolidinone (II), l,3,5-triphenyl-s-triazine-2,4,6-(líf,3íf,5H)-trione (III), 1,3,5-tricyclohexyls-triazine-2,4,6-(IH,3H,8H)-trione (IV), and butyl phenylcarbamate] by using and IR-sealed ampule method, developed for these measurements. The kinetics of the initial stage of the thermal decomposition of the model compounds followed first-order kinetics and the kinetic parameters E", A, and TD were determined. It was found that thermal stability of the above-mentioned groups increased in the following order: carbamate < oxazolidone < isocyanurate. The activation energies increased in the same order. Model oxazolidones with the cycloaliphatic substituent on the nitrogen had higher thermal stability than oxazolidones with the aromatic (phenyl) substituent. The cleavage of the oxazolidone rings proceeded through the formation of carbon dioxide and other intermediates which further decomposed, forming aniline, phenol, and various hydrocarbons.

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The preparation of poly[oxy-(2,6-dimethyl)-1,4-phenylene] (2) via polymerization of 2,6-dimethylphenol (1) by oxidative coupling with CuC12-amine complexes is described. The reaction mechanism was studied by means of ESR, NMR spectroscopy, and conductivity measurements. It was established that the C< coupling products (dipheno-quinones) are formed by recombination of phenoxyl radicals and that the very high selectivity of the CuC12-amine complex catalysts in the formation of 2 ( C 4 coupling) is due to the cationic mechanism based on the consecutive reaction of the phenoxyl radicals with Cu(I1) complexes. This consecutive reaction of the phenoxyl radicals with Cu(I1) complexes is responsible for the non-measurable level of polymeric radicals 5 by ESR, previously reported. ZUSAMMENFASSUNG:Die Darstellung von Poly[oxy-(2,6-dimethyl)-lP-phenylen] (2) via Polymerisation von 2,6-Dimethylphenol (1) durch oxidative Kupplung rnit CuC12-Amin-Komplexen wird beschrieben. Der Reaktionsmechanismus wurde rnit Hilfe von ESR, NMR-Spektroskopie und Leitfahigkeitsmessungen untersucht. Es wurde festgestellt, daR die C-C-Kupplungsprodukte (Diphenochinone) durch Rekombination von Phenoxyl-Radikalen gebildet werden, und daR die sehr hohe Selektivitat der CuCl,-Amin-Komplexe bei der Bildung von 2 (C-0-Kupplung) auf einem kationischen Mechanismus beruht, der auf eine aufeinanderfolgende Reaktion der Phenoxyl-Radikale mit den Cu(I1)-Komplexen zuriickgefuhrt wird. Diese aufeinanderfolgende Reaktion der Phenoxyl-Radikale rnit den Cu(I1)-Komplexen ist verantwortlich fur den, rnit Hilfe der ESR-Methode nicht meRbaren, geringen Gehalt an polymeren Radikalen 5, woriiber in einer vorhergehenden Arbeit berichtet wurde.

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