Poly(3-phenylquinoxaline): a new thermally stable polymer

A high-performance phenylquinoxaline polymer was prepared by a three-step synthetic route employing a reductive polycyclization process. This method involves in situ generation of the monomer 3,4-diaminobenzil by reducing the precursor 3-nitro-4-aminobenzil. A nearly quantitative yield of poly(3-phenylquinoxaline) was obtained, and its physical properties were similar to those of the known poly(2,2'-(1,4-phenylene)-6,7'-bis(3-phenylquinoxaline)) and isomers. 3,4-diaminobenzil prepared from dithionite reduction of 3-nitro-4-aminobenzil polycyclized at a rate slower than the classical two-component system. Spectra. 19 ref.--AA