Activated carbon-catalyzed hydrogen transfer to α,ω- Diarylalkanes

Diphenylmethane (DPM), 9-benzylphenanthrene (BP), di(1-naphthyl)methane (DNM), 1,2-di-(1-naphthyl)ethane (DNE), and 9-(l-naphthyl)phenanthrylmethane (NPM) were used as substrates and hydrogen-transfer reactions from molecular hydrogen to the substrates were examined over an activated carbon (AC) under pressurized hydrogen at 300 °C. The results show that the AC catalyzes monatomic hydrogen transfer to the substrates and that the reactivities of the substrates toward hydrocracking decrease in the following order: NPM 〉 DNM 〉 BP ≫ DNE ≫ DPM. These results can be interpreted by the differences in the hydrogen-accepting abilities of the ipso-carbons and the resonance stabilities of the leaving radicals.