The Catalytic Performance of Metalloporphyrins during Hydrogenation of Anthracene

The potential catalytic performance of metalloporphyrins (MPs) for the hydrogenation of anthracene was investigated. The hydrogenation of anthracene with MPs, sulfur, or a combination of both was investigated. The MPs showed a small amount of catalytic activity for the hydrogenation reaction. Sulfur markedly improved the catalytic activity of the MPs. To probe demetalation of the MPs and the formation of catalytic species, conversions of the MPs were evaluated by UV/Vis spectroscopy. The solids formed in situ with alpha-Al2O3 as a carrier during the hydrogenation with nickel tetraphenylporphyrin and sulfur were characterized by Raman, X-ray photoelectron (XPS), and energy-dispersive X-ray spectroscopy (EDS). In the presence of sulfur, high conversions of the MPs were obtained. Raman spectroscopy, XPS, and EDS analyses suggested that the catalytic species were mixtures of different nickel sulfide phases with NiS as the main component. Thus, with the aid of sulfur, the MPs could be readily demetalated and then sulfided to catalytic species, and thus it is possible to activate inherent MPs to improve the hydroconversion of heavy oil.