Comparative study of alumina- and carbon-supported catalysts for hydrogenolysis and hydrogenation of model compounds and coal-derived liquids

Carbon- and alumina-supported Fe, Mo, Fe-Mo, and Co-Mo sulfide catalysts were compared for their ability to catalyze hydrotreating reactions such as dibenzothiophene hydrodesulfurization, quinoline hydrodenitrogenation, dibenzofuran hydrodeoxygenation, and hydrogenation of butenes, naphthalene, biphenyl, and coal extract. The temperature and pressure varied from 653 to 703 K and from 1 to 300 bar of H2 respectively. Below 50 bar of H, the carbon-supported catalysts were more active for hydrogenolysis and hydrogenation than the aluminasupported ones. However, further H, pressure increase was most effective for the latter catalysts. The activity differences between carbon- and alumina-supported catalysts are ascribed to differences in active phase-support interaction. Generally, iron sulfide was found less active than molybdenum sulfide, and iron sulfide also appeared to be less effective than cobalt sulfide in promoting molybdenum sulfide. However, the Fe-Mo sulfide showed the higher selectivity for hydrogenation relative to hydrodesulfurization. Carboksupported iron sulfide (low-cost catalyst) had considerable activity for coal extract hydrogenation.