Catalytic activities of metal oxides containing iron for hydrocracking coal model compounds and Taiheiyo coal

Twenty-five catalysts of metal oxides principally containing iron were prepared and examined in hydrocracking of coal model compounds: diphenyl ether, diphenylmethane and benzyl phenyl ether. Highly active catalysts were Fe2O3-I and -II and Fe2O3-TiO2 for diphenyl ether, Fe2O3-I and -II and Fe2O3-SiO2 for diphenylmethane, and sulfated Fe2O3-I, -II and -III and Fe2O3-TiO2 together with WO3/ZrO2 for benzyl phenyl ether. The best method for preparation of iron oxide was precipitation of the hydroxide from the nitrate with ammonia followed by calcination. The catalysts were tested for the liquefaction of Taiheiyo coal using a high-pressure d.t.a. apparatus; sulfated Fe2O3-TiO2 was most effective, and the order of activity was similar to that for benzyl phenyl ether. From the results of hydrocracking of model compounds and liquefaction of Taiheiyo coal, both C-C and C-O bond cleavages are discussed on the basis of acid property and hydrogenation ability of the catalysts. (C) 1997 Elsevier Science Ltd.