Perfluoroalkyl- and perfluoroalkylether-substituted quinoxalines

Article abstract of DOI:10.1016/0022-1139(96)03410-0

A series of perfluoroalkyl-and perfluoroalkylether-substituted quinoxalines was synthesized to determine the effect of the attachment of the perfluorinated unit to the heterocyclic ring (directly or via a phenyl group) and the effect of the nature of the perfluoroalkylether chain on the thermal and oxidative stability. Both model compounds and polymeric materials were investigated. Quinoxalines wherein the heterocyclic rings were bridged by polyperfluoroalkylethers with either two or three CF₂ groups separating the ether oxygen from the heterocyclic ring were thermally stable below 316 °C. A polyquinoxaline system linked by a p-C₆H₄(CF₂)₃O(CF₂)₄O(CF₂)₄O(CF₂)₃-p-C₆H₄ chain exhibited thermal and thermal oxidative stability above 330 °C. Having two CF₂ groups separating the aromatic ring from the ether oxygen led to a significantly lower stability and difficulties in the intermediate tetraketone synthesis.