POLY(ALKYL BENZOATE)S - PREPARATION, PROPERTIES AND CONVERSION TO POLYPHENYLENES

Poly(alkyl benzoate)s were prepared by the coupling of alkyl dichlorob enzoates with zerovalent nickel generated in situ from nickel(II) brom ide and characterized by H-1 NMR spectroscopy. While the spectra of th e substituted poly(p-phenylene)s were complicated by the irregular dis tribution of substituents and the flipping of the phenylene rings, the spectra of poly(m-phenylene) derivatives were simple. In the spectra of poly(dodecyl-p-phenylene), the relative positions of the two signal s due to the cu-methylene group, associated with head-to-tail and head -to-head bondings of the phenylene rings, were reversed upon the intro duction of the methoxycarbonyl group. The poly(alkyl benzoate)s melted under microscopic observation and thermally decomposed in two stages. The decomposition temperature ranged from 380 to 460 degrees C for th e first stage and from 550 to 590 degrees C for the second stage. Thes e findings indicated that these polymers were soluble, fusible and the rmally stable. The poly(alkyl benzoate)s were hydrolysed and decarboxy lated to the corresponding polyphenylenes. Although the substituted po ly(p-phenylene)s were easily converted to polyphenylenes, the poly(m-p henylene) homologues were resistant to hydrolysis.