Polymerization of aromatic nuclei. X. Polymerization of benzene to p‐polyphenyl oligomers by nitrogen dioxide—aluminum chloride

Abstract

SynopsisBenzene was polymerized to p-polyphenyl oligomers by nitrogen dioxidealuminum chloride. Polymer production was favored by AlClS:N02 ratios of at least 2, long reaction times, and higher temperatures. Evidence for the polymer structure was obtained from elemental analyses, oxidative degradation, solubility, molecular weight, functional group tests, low molecular weight products, and infrared and ultraviolet spectra. The chains contained small amounts of chloro, amino, hydroxyl, and carboxyl substituents. Molecular weight data on the benzene-soluble portion (40-71%) revealed an average of 4-6 phenylene units per chain. Under altered conditions nitrobenzene could be obtained as the major product, indicating the sensitivity of the system to changes in reaction variables.The theoretical aspects are discussed.With nitrobenzene as oxidant, a similar type of polymer resulted.

Dimensional Evolution of Polyphenylenes: Expanding in All Directions

“…This process is commonly known as the Scholl reaction (Figure , black scheme) and is still used for various aryl–aryl couplings . It was found that the resulting molecular weight was heavily dependent on the reaction temperature and concentrations, while the lack of solubility of the PPP made it impossible to fully characterize and process polymers of significant size (molecular weight greater than 2–3 kg/mol). − …”