Polymerization of aromatic nuclei. XVII. Catalytic hydrogenation of poly(p‐phenylene)

Abstract

Hydrogenation of poly(p‐phenylene) (I) in cyclohexane at high temperature and pressure with rhodium catalyst gave, in low yield, oligomers of 1,4‐cyclohexylene(II) in the range of 2–16 cyclohexyl units per chain. Apparently only the low molecular weight fraction in I is reduced because of extreme insolubility. II, which appears to be a novel class, was characterized by molecular weight, 1H‐NMR, 13C‐NMR, and infrared spectra, gas chromatography, and microanalyses. Dicyclohexyl and perhydro‐p‐sexiphenyl served as model compounds for comparison in characterization of II.