Benzene and four polycyclic arenes (PAs) were used as substrates and their hydrogenation reactions were conducted over activated carbon (AC) at 300 °C to examine the relationship between their molecular structures and reactivities. The results show that the AC catalyzed the hydrogenation of the PAs selectively and that the reactivities of the arenes toward hydrogenation were dependent on the hydrogen-accepting abilities of the arenes and on the adsorption strengths of the arenes on the catalyst surface. The related mechanisms for hydrogen transfer were also discussed.

Hydrogenation reactions of three polycyclic arenes (PCAs), that is, anthracene, 9-phenylanthracene (PA), and 9,10-diphenylanthracene (DPA) were carried out under an initial hydrogen pressure of 5 MPa at 300 °C. An activated carbon (AC, a metal-free catalyst), was employed to catalyze the PCA hydroconversions. The results show that the AC can split gaseous hydrogen into atomic form and catalyze monatomic hydrogen transfer to aromatic rings. Interestingly, the AC selectively catalyzed the hydrogenation of the anthracene ring, and prevented the benzene ring from hydrogenation and the C-C linkage from cleavage. The reactivity of the PCAs toward hydrogenation over the AC decreased in the order of anthracene > PA > DPA. The hydrogen-accepting ability and steric hindrance effect are demonstrated to be responsible for the difference in reactivity.

The tetrahydrofuran/carbon disulfide (THF/CS2) mixed solvent-insoluble portion of Upper Freeport coal was subject to noncatalytic and nickel-catalyzed hydrothermal treatments under pressurized hydrogen at 300 °C. The petroleum ether (PE)-soluble fractions from the reaction mixtures were analyzed using gas chromatography (GC) and gas chromatography/mass spectroscopy (GC/MS). Twenty-two organic sulfur compounds (OSCs) were detected in the PE-soluble fraction from the reaction mixture of noncatalytic hydrothermal treatment, whereas only very small amounts of two OSCs were detected in the PE-soluble fraction from the reaction mixture of nickel-catalyzed hydrothermal treatment, suggesting that the thermally released OSCs from the insoluble portion were effectively removed by the nickel catalyst. The related mechanisms were discussed.

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